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ALT="Linux Gazette... making Linux just a little more fun!">
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<H5>Copyright &copy; 1996-98 Specialized Systems Consultants, Inc.</H5>
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<H1>Welcome to Linux Gazette!<img src="../gx/tm.gif" alt="(tm)"></H1>
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<H1>Published by:</H1>
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<H1>Sponsored by:</H1>
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Our sponsors make financial contributions toward the costs of
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of <I>LG</I>, e-mail us at <A
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<I>Linux Gazette</I> is a non-commercial, freely available publication and will
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<!--=================================================================-->
<H1 align="center">Table of Contents <BR>April 1998 Issue #27</H1>
<P> <HR> <P>
<table><tr>
<td rowspan=4>
<UL>
<LI><A HREF="../index.html">The Front Page</A>
<LI><A HREF="./lg_mail27.html">The MailBag</A>
<ul>
<li><a HREF="./lg_mail27.html#help">Help Wanted</a>
<li><a HREF="./lg_mail27.html#gen">General Mail</a>
</ul>
<LI><A HREF="./lg_tips27.html">More 2 Cent Tips</A>
<ul>
<li><a HREF="./lg_tips27.html#shane">Re: Help Wanted LaserJet 4L</a>
<li><a HREF="./lg_tips27.html#fraser">StarOffice 4/Ghostscript</a>
<li><a HREF="./lg_tips27.html#rc">Linux and VAX 3400 and 3300</a>
<li><a HREF="./lg_tips27.html#caolin">xdm with pictures</a>
<li><a HREF="./lg_tips27.html#caolin2">Re: Help-Installing Linux on a FAT32</A>
<li><a HREF="./lg_tips27.html#john">Regarding Easter Eggs in Netscape etc.</a>
<li><a HREF="./lg_tips27.html#craige">Re: Changing XDM windows</a>
<li><a HREF="./lg_tips27.html#serge">Nice xdm and Linux PPC</a>
<li><a HREF="./lg_tips27.html#roland">Re: Help with Sound Card</a>
<li><a HREF="./lg_tips27.html#tips">Lots More</a>
</ul>
<LI><A HREF="./lg_bytes27.html">News Bytes</A>
<ul>
<li><a HREF="./lg_bytes27.html#general">News in General</a>
<li><a HREF="./lg_bytes27.html#software">Software Announcements</a>
</ul>
<LI><A HREF="./lg_answer27.html">The Answer Guy</A>, by James T. Dennis
<ul>
<li><a HREF="./lg_answer27.html#mccluan">Regarding Compile Errors with
Tripwire 1.2</a>
<li><a HREF="./lg_answer27.html#karsh">Applix Spreadsheet ELF Macro
Language</a>
<li><a HREF="./lg_answer27.html#geene">Answer Guy Issue 18 -- Procmail Spam
Filter</a>
<li><a HREF="./lg_answer27.html#geene2">Great Procmail Article</a>
<li><a HREF="./lg_answer27.html#sindona">Linux Cluster Configuration</a>
<li><a HREF="./lg_answer27.html#holloway">IP Masquerading/Proxy?</a>
</ul>
<LI><A HREF="./kodis.html">Autologin with mingetty</a>, by John Kodis
<LI><A HREF="./little.html">Checking Out SPARC-Linux with SLXT</a>, by
John Little
<LI><A HREF="./marsden.html">EMACSulation</a>, by Eric Marsden
<LI><A HREF="./wagle.html">Evangelism: A Unix Bigot and Linux Advocate's
Spewings</a>, by David Wagle
<LI><A HREF="./jeffery.html">A Glimpse of Icon</a>, by Clinton Jeffery and
Shamim Mohamed
<LI><A HREF="./gm.html">Graphics Muse</A>, by Michael J. Hammel
<LI><A HREF="./dibona.html">Linus Speaks at SVLUG Meeting</a>, by Chris
DiBona
<LI><A HREF="./adelman.html">Markup Languages and lout2</a>, by Murray Adelman
<LI>New Release Reviews, by Larry Ayers
<ul>
<LI><A HREF="./ayers1.html">Using the Flame Plug-In for Backgrounds</A>, by Larry Ayers
<LI><A HREF="./ayers2.html">The Maxwell Word-Processor</A>, by Larry Ayers
<LI><A HREF="./ayers3.html">WordNet: A Fast and Flexible Word Database</A>, by Larry Ayers
<LI><A HREF="./ayers4.html">Words Within Words, New Phrases From Old</A>, by Larry Ayers
<LI><A HREF="./ayers5.html">Comparing WordPerfect and LyX</A>, by Larry Ayers
</ul>
<LI><A HREF="./mueller.html">Pattern Matching with Regular Expressions in
C++</a>, by Oliver M&uuml;ller
<LI><A HREF="./petersen.html">Book Review: Web Security Sourcebook</a>, by
Kirk Petersen
<LI><A HREF="./wkndmech.html">Weekend Mechanic</A>, by John
Fisk
<LI><A HREF="./kaszeta.html">X Window System Terminals</a>, by Rich Kaszeta
<LI><A HREF="./lg_backpage27.html">The Back Page</A>
<ul>
<li><a HREF="./lg_backpage27.html#authors">About This Month's Authors</a>
<li><a HREF="./lg_backpage27.html#notlinux">Not Linux</a>
</UL>
</UL>
</td>
</tr>
<tr>
<td align=center>
<A HREF="linuxexpo.html">
<img src="../gx/linuxexpo.gif" border=0 alt="">
</a>
</td>
</tr><tr>
<td align=center>
<A HREF="lg_answer27.html">
<img src="../gx/wizard2.gif" border=0 alt="">
</a><BR>
<A HREF="lg_answer27.html"><i>The Answer Guy</i></a>
</td>
</tr><tr>
<td align=center>
<A HREF="gm.html">
<IMG SRC="../gx/hammel/banner-3.gif" border=0 alt="">
</a>
</td>
</tr><tr>
<td align=center>
<A HREF="./wkndmech.html">
<img src="../gx/fisk/mechanic.gif" border=0 alt=""></A><BR>
<A HREF="./wkndmech.html"><I>The Weekend Mechanic</I></a>
</td>
</tr><tr>
</table>
<P> <HR><P>
<!--=============================================================-->
<A HREF="./issue27.txt">TWDT 1 (text)</A><BR>
<A HREF="./issue27.html">TWDT 2 (HTML)</A><BR>
are files containing the entire issue: one in text format, one in HTML.
They are provided
strictly as a way to save the contents as one file for later printing in
the format of your choice;
there is no guarantee of working links in the HTML version.
<!--=============================================================-->
<P> <HR><P>
Got any <I>great</I> ideas for improvements? Send your
<A HREF="mailto:gazette@ssc.com">comments, criticisms, suggestions
and ideas.</A>
<P><hr><p>
This page written and maintained by the Editor of <I>Linux Gazette</I>,
<A HREF="mailto: gazette@ssc.com"> gazette@ssc.com</A>
<P> <HR> <P>
<H4>"Linux Gazette...<I>making Linux just a little more fun!</I>"</H4>
<HR>
<center>
<table width="100%" cellpadding=7><tr><td>
<H2><a NAME="mail"><IMG SRC="../gx/mailbox.gif" ALIGN=MIDDLE ALT=" ">
The Mailbag!</a> </H2>
Write the Gazette at <A HREF="mailto:gazette@ssc.com"> gazette@ssc.com</A>
</td><td>
<H3>Contents:</H3>
<ul>
<li><a HREF="./lg_mail27.html#help">Help Wanted -- Article Ideas</a>
<li><a HREF="./lg_mail27.html#gen">General Mail</a>
</ul>
</td></tr></table>
</center>
<a name="help"></a>
<p><hr><p>
<!-- =================================================================== -->
<center><H3> Help Wanted -- Article Ideas </H3></center>
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Mon, 02 Mar 1998 08:48:14 +0100<BR>
From: Per Wigren, <A HREF="mailto:wigren@mail.org">
wigren@mail.org</A> <BR>
Subject: <B>Linux and CDE</B>
<P>
Hi! I want to know what makes XiG's and TriTeal's CDE
different, other than price!
Maybe a comparison could be something for <I>Linux Gazette</I>...
<P>
Regards, Per Wigren
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Mon, 2 Mar 1998 18:56:35 +0100 (MET)<BR>
From: Scud, <A HREF="mailto:scud@zeus.ho.tranas.se">
scud@zeus.ho.tranas.se</A> <BR>
Subject: <B>article idea</B>
<P>
I wonder if you can write some article about linux
on non x86 platforms and how long linux develelopment
has come on those platforms?
<P>
emir
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Sat, 28 Feb 1998 18:47:55 +0100<BR>
From: Grzegorz Leszczynski, <A HREF="mailto:rexus@polbox.com">
rexus@polbox.com</A> <BR>
Subject: <B>Hurricane</B>
<P>
I would be very grateful if you could help me with my problem.
I can't install Linux Red Hat Hurricane 5.0.
After choosing the partitions to Linux native and for swap Linux,
and after choosing applications to install program says
that there is an error:
<pre>mount failed: invalid argument</pre>
After than i must return to menu and I don't know what to do.
I look forward from hearings from you
<P>
Rafal Leszczynski, POLAND
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Sun, 1 Mar 1998 14:11:18 -0500 (EST)<BR>
From: N. Lucent, <A HREF="mailto:nlucent@mindspring.com">
nlucent@mindspring.com</A> <BR>
Subject: <B>Linux on a laptop</B>
<P>
I finally convinced my girlfriend to make the switch to Linux from windows
after she suffered numerous stability problems (big surprise) She
currently has an HP Omni-book 600CT, I fdisked her windows partition, and
when I ran the install boot disk (for both Red Hat and Slackware) it says
floppy 1.44m (I assume this is from the kernel) Then it says no floppy
controller found, and just keeps reading the boot disk. Is there anyway
that I can force the detection of the floppy? (external floppy drive)
I found a WWW page about installing Linux on that notebook, but What it
said to do didn't work. Does anyone have any suggestions?
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Thu, 5 Mar 1998 03:09:06 EST<BR>
From: Mktnc, <A HREF="mailto:Mktnc@aol.com">Mktnc@aol.com</A> <BR>
Subject: <B>Matrox Millenium II</B>
<P>
Anyone using the Matrox Millenium II graphics board with greater than 4 Meg
ram with Xfree86? The XFree86 home page is somewhat dated on this card.
<P>
Also, anyone running a Voodoo 2 accelerator graphix card with Linux?
<P>
Anyone using nasm (Netwide Assembler) for those hard to reach places, under
Linux?
<P>
Thanks - Nick
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Wed, 04 Mar 1998 09:05:00 -0500<BR>
From: Dr. Scott Searcy, <A HREF="mailto:searcys@baydenoc.cc.mi.us">
searcys@baydenoc.cc.mi.us</A> <BR>
Subject: <B>X-term for MS-Windows </B>
<P>
Does anyone make an X-windows terminal emulator that will run under
MS-Windows. I was hoping to find such a program so that I could use X
via a network connection from various MS-windows machines that I have to
use.
<P>
Dr. Scott Searcy
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Thu, 05 Mar 1998 23:38:29 -0700<BR>
From: Elvis Chow, <A HREF="mailto:elvis3@chowtech.cuug.ab.ca">
elvis3@chowtech.cuug.ab.ca</A> <BR>
Subject: <B>Hylafax printing filter?</B>
<P>
I finally got Hylafax running on a Slackware distribution. Works
great. What I need to do now is to get Applixware to print a doc
directly to it so it can automatically fax it to a predetermined
number. Is there a way of doing this?
<P>
Great work on the Gazette! Best source of practical tips I've run
across in a long time. Keep it up!!
<P>
Elvis Chow elvis@chowtech.cuug.ab.ca
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Fri, 06 Mar 1998 18:42:43 +0100<BR>
From: Stefano Stracuzzi, <A HREF="mailto:stracca@comune.modena.it">
stracca@comune.modena.it</A> <BR>
Subject: <B>PPP with Linux</B>
<P>
I'm a newbie in Linux and I'd like to know
how I can configure my connection to my
Internet service provider with my Red Hat 5.0!
<P>
My modem is internal and it is configured to on the
cua1
<P>
Thank You Very Much<BR>
Stefano Stracuzzi
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Mon, 9 Mar 1998 10:43:30 -0800<BR>
From: jean-francois helie, <A HREF="mailto:jfhelie@netrover.com">
jfhelie@netrover.com</A> <BR>
Subject: <B>Help Wanted!</B>
<P>
I am a student at CEGEP T.R. I have a year end project. My project
is to installed a Linux based router and a IP generator for 50 PC. I have
some informations about the router but i don't have any info about IP
generator.
<P>
Thank you for your support.<BR>
Jean-Francois Helie
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Wed, 11 Mar 1998 15:51:30 +1000<BR>
From: Ken Woodward, <A HREF="mailto:ken@rich.com.au">ken@rich.com.au</A>
<BR>
Subject: <B>Linux for Amiga</B>
<P>
Do you know if it is possible to get a CD distribution of Linux to suit
running on an Amiga 3000? It is currently running AmigaUnix, and the Red
Hat version 5 copy I purchased installed flawlessly on my PC.
<P>
Can I get the same for the old Amiga?
<P>
Thanks<BR>
Ken
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Wed, 11 Mar 1998 12:58:10 -0800<BR>
From: Kevin Long, <A HREF="mailto:kevjlong@ix.netcom.com">
kevjlong@ix.netcom.com</A> <BR>
Subject: <B>Samba Woes</B>
<P>
Here's my situation: I'm trying to set up my RH5 terrifically working
system to be a PDC equivalent in an NT workstation/95 network. Basically
we need to 'login' to the server, and then get access to 'shares'. I
tried using NFS as an alternative (with NFS maestro) but it doesn't
recognize Linux NFS. However...... I cannot get Samba to work AT ALL. In
fact, I have never seen it work. If you've got it working, please help
me - I can copy your installation configuration and tweak it, but I need
some success. I have plenty of NT, Novel, DOS/win hardware etc.
experience, and successfully use NFS exports between Linux machines, but
have got nowhere with Samba in a year of trying. Is it a hoax?
<P>
Kevin Long
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Thu, 12 Mar 1998 14:55:56 +0800<BR>
From: Jason Wong, <A HREF="mailto:jasonw@tntexpress.com.hk">
jasonw@tntexpress.com.hk</A> <BR>
Subject: <B>Red hat 5.0 with NT Server 4</B>
<P>
I am new to Linux, and wish to set it up at home. The problem I have
is:
<P>
I wish to run Windows NT + Windows 95 + DOS + Linux. How to do this?
I can set it up with Linux & Windows 95/DOS, but how to make Linux
co-exist with NT server4?? many thanks!!
<blockquote> <I>
(See the Samba page, http://samba.anu.edu.au/samba/. It should be just what
you need. --Editor)</I> </blockquote>
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Fri, 13 Mar 1998 10:18:33 +0100 (MET)<BR>
From: Fabio Gregoroni, <A HREF="mailto:gregoron@CsR.UniBo.IT">
gregoron@CsR.UniBo.IT</A> <BR>
Subject: <B>Driver For Scanner</B>
<P>
I have to write a driver for a plain scanner on the parallel port.
I have following scanners:
<ol>
<li>PRIMAX 4800 COLORADO DIRECT
<li>PLUSTEK 4830P
</ol>
I don't need the driver already made, but I need only the transfer
protocol documentation ( what I must send and receive ).
Can Someone help me ?
<P>
Thanks.
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Wed, 04 Mar 1998 04:53:01 +0800<BR>
From: ahyeop, <A HREF="mailto:ahyeop4@tm.net.my">ahyeop4@tm.net.my</A>
Subject: <B>X-Windows too Big!</B>
<P>
Lastly I successful install the X-windows for my Linux box using generic
chip set or
Oak's OTI067 (8 physical RAM is quite slow though..). But the windows
are too BIG.
I tried modified its XF86Config but it's not working (besides I really
doesn't know
how to modified it correctly)
<pre>
My box spec : processor: 486 DX2 60MHz.
RAM: 8 simm ram
Swap memory: 16 swap ram (I think so...)
memory: 256 Kbytes
RAMDAC: Generic 8-bit pseudo-color DAC (what it
mean ?)
Linux: Linux ver. 2.0.27 (Slackware 96)
monitor: SVGA monitor (SSVM's 220-240V-50MHz
500mA)
video card: Oak's OTI067
mouse: MS Mouse
Keyboard: 101-key
</pre>
Can anybody help me with problem ? Thank in advance :-)
<P>
Ahyeop, Perak, Malaysia
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Wed, 25 Mar 1998 11:25:32 -0100<BR>
From: BoD, <A HREF="mailto:M39998@lazaro.info-ab.uclm.es">
M39998@lazaro.info-ab.uclm.es</A> <BR>
Subject: <B>AGP card on Linux</B>
<P>
I like to buy a AGP card based in the nVIDIA RIVA 128 chipset.
Can i use it on my Linux RH 5.0 system with Xfree86 3.3.1?
<P>
Thanks
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Thu, 26 Mar 1998 11:41:11 -0800 (PST)<BR>
From: Lee, <A HREF="mailto:cit@itl.net">cit@itl.net</A> <BR>
Subject: <B>Re: Linux Gazette</B>
<P>
I've recently been hit by the superforker problem. Someone mentioned that the LG had a script to fix the problem (by removing the directories in /tmp)
Do you have such a script? I haven't been able to locate it, and I currently have a ton of directories in /tmp that rm won't remove because the filename is too long.
<P>
Please respond quickly while I still have some hair left,<BR>
Lee//Cit
<blockquote> <I>
(Sorry, I don't remember all the articles we've had, but superforker doesn't
sound familiar.
However, in issue 18 and 20, Guy Geens has articles about cleaning up the
/tmp directory. Perhaps these will be of help to you. --Editor) </I>
</blockquote>
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Fri, 27 Mar 1998 09:06:39 +0100 <BR>
From: javier ballesteros, <A HREF="mailto:uei0372195900@eurociber.es">
uei0372195900@eurociber.es</A> <BR>
Subject: <B>modem for Linux</B>
<P>
I'm a student of telecommunications in the University of Alcala de
Henares in Spain, my computer is a Pentium 233 MHz and I have installed
Red Hat Linux 5.0, all works properly , but I have a little problem with
my modem: Linux can't recognize my modem. My modem is a HSP 336 DELUXE
(I know that is very bad but is the only I have). So, is there any
possible to install properly my modem? , exist any driver for this
specific modem? .Please send me some information or any advice, if you
can I will be pleasant.
<P>
See you!....
<a name="gen"></a>
<P> <hr> <P>
<!-- =================================================================== -->
<center><H3> General Mail </H3></center>
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Fri, 13 Mar 1998 00:39:33 -0700 (MST)<BR>
From: Michael J. Hammel, <A HREF="mailto:mjhammel@csn.net">
mjhammel@csn.net</A> <BR>
Subject: <B>Late Night Radio Buzz</B>
<P>
I'm sitting here listening to C|Net radios
coverage of Internet World. Dan Shafer of Builder.com talked at length
about how he (and someone named Desmond) are going to do some
serious investigation into what alternative OS's there are - and
specifically they are looking into Linux. They mentioned Red Hat and
Caldera, that there were lots of applications available and how the Linux
community are very much the "just do it" community. All in all, very
positive exposure.
<P>
Go to http://www.news.com/Radio/Features/0,155,154,0.html and click on the
4:00 CNET Radio Late Update (where it says "Dan Shafer of Builder.com:
What's Hot?"). Its a RealAudio interview and you'll have to go about 1/2
way through before they start the Linux discussion.
<P>
Dan Shafer said they would be writing up the Linux results they came up
with in the BuilderBuzz section of Builder.com (http://builder.com). I
just checked and there is nothing there yet - I think he said it was going
to start next week. Anyway, I sent him email offering to assist in anyway
I could. If I get a response I'll try to get more details on where the
info will be located when it becomes available.
<P>
C|Net would be wonderful exposure for Linux.
<P>
Just thought I'd pass this along.
Michael J. Hammel |
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Mon, 02 Mar 1998 23:22:14 +0500<BR>
From: Larry Taranenko, <A HREF="mailto:larry@partners.chel.su">
larry@partners.chel.su</A> <BR>
Subject: <B> Re: Linux Gazette #26</B>
<p>
You know, we are here interesting in Linux too. But we have much troubles
with our unstable connection to the World - that is why I maintained LG
mirror in the heart (geographically we live in the center of RUSSIA) of
my country. And I have many many friends in my town (apr. 2,5 mln city
named Chelyabinsk) who are crazy about Linux as I am. Mostly we use
Debian. I like your publications - and think that a little note
somewhere there about Linuxoids in RUSSIA will be, maybe, interesting to
somebody. See in future.
<p>
I hope you understand me in right manner, against my silly English...<BR>
God bless you and Linus, <BR>
Have a nice day!<BR>
Ta-ta
<blockquote> <I>
(I think I understand you fine. Why don't you write up an article for us
about Linux in Russia? --Editor) </I> </blockquote>
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Fri, 27 Mar 1998 03:49:43 -0500 (EST)<BR>
From: <A HREF="mailto:zaeb@8b28m2.net">zaeb@8b28m2.net</A> <BR>
Subject: <B>about filedudes</B>
<p>
hey, found this real fast download site www.filedudes.com,
check it out!
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Sat, 07 Mar 1998 22:51:10 -0800<BR>
From: Ken Leyba, <A HREF="mailto:kleyba@pacbell.net">kleyba@pacbell.net</A>
<BR>
Subject: <B>$0.02 Tip</B>
<p>
In issue 26 of the Linux Gazette there is a two cent tip that refers to
the VAX 3400/3300's as MIPS 3000 boxes. These are indeed VAX
processors as Digital (DEC) named MIPS boxes as DECStations/DECServers
and VAX boxes as VAXStations/VAXServers. I worked for Digital for over
10 years in Multi-Vendor Customer Services and currently use a VAX 3300
running Ultrix, DEC's BSD based Unix for the VAX CPU.
<p>
Ken Leyba
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Mon, 9 Mar 1998 17:09:28 -0500<BR>
From: Tunney, Sue (IDS), <A
HREF="mailto:STunney@ahcpr.gov">STunney@ahcpr.gov</A><BR>
Subject: <B>Yes, Grammar does count</B>
<p>
I was so pleased to read that *someone* else out there is as aggravated
as I am by the continual misuse of the apostrophe in web pages and
e-mails by obvious native-born American English speakers. And for
anyone who says, "What's the big deal? Doesn't everyone know what I
mean?", let this old fogey respond:
<p>
Does your computer understand what you mean when you make an error
writing code? Doesn't it matter then? If you can't write proper English
grammar and spell correctly, what makes you so sure that your computer
code is correct? And if you want to spread the good news about Linux, it
seems obvious that we will get more attention, and the right kind, if we
take the time to write properly. I'm often impressed by how hard the
"foreign" letter writers work to make their point clear when they write
to LG, often apologizing for their poor English; yet they often do
better than us "natives."
<p>
Mike, you are absolutely right, and I thank you for saying it. I would
also like to eliminate the so-called word "alot" as *there is no such
word* (but note that the next letter after Mike's used it. Oh, well...)
. If you can't drag out a dictionary, check it out on line; there are
lots of fine dictionaries out there.
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Thu, 12 Mar 1998 13:24:03 -0800<BR>
From: Rich Drewes, <A HREF="mailto:drewes@interstice.com">
drewes@interstice.com</A> <BR>
Subject: <B>Linux market share (news tidbit)</B>
<p>
I run an ISP that hosts a variety of customer-owned domains, most not
even specifically computer related. I recently did an analysis of the
agent_log files to find out how popular Linux really is as a client OS
for ordinary users who access the ordinary web pages. The results are
at:
<p>
http://www.interstice.com/~drewes/linuxcount/main.html
<p>
One interesting factoid: Linux now appears to be the #2 most popular
Unix OS client!
<p>
I enjoy the LG. Thanks for the work.<BR>
Rich
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Thu, 12 Mar 1998 21:38:36 -0500 (EST)<BR>
From: Tim Gray, <A
HREF="mailto:timgray@lambdanet.com">timgray@lambdanet.com </A> <BR>
Subject: <B>Re: Getting Linux to the public...</B>
<p>
Milton, thank you for your response (see <A
HREF="./lg_tips27.html#milton">Tips</A>)... your's was the first that was genuinely
helpful, I have learned many things after posting that letter to the
Gazette, one of which is that the Linux user crowd is not free of the
type of person that enjoys flaming others, (I had secretly hoped that
Linux users were more helpful than resentful) But thank you! It helps
alot to fiddle with the settings and I was successful in getting 2 friends
converted to Linux, unfortunately there are several colleagues that alas
have monitors that are older than dirt itself and cannot go beyond
640X480 :-) But you have helped me migrate 2 windows users! thank you..
and thank you for your supportive letter.
<p>
Tim.
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Sun, 29 Mar 1998 16:09:41 -0500<BR>
From: NYACC AnyNix SIG comm mgr, <A HREF="mailto:sigunix@bzsys.dyn.ml.org">
sigunix@bzsys.dyn.ml.org</A>
Subject: <B>Re: Getting Linux to the public...</B>
<P>
Timothy D. Gray wrote regarding: Getting Linux to the public:
<blockquote> <I>
Has anyone noticed that when your friends see your neat-o Linux system
with the nice 17 inch monitor, high quality video card, and fast
computer that when they say, "Wow! that is nice, and you can do almost
anything on that!" you cringe with the fact that they are going to
want you to put it on their system?
</I> </blockquote>
I'm glad you have a 17inch monitor and "highquality" video card.
Myself, my 50-dollar video card and ten-year-old monitor let me run in
800x600 with 256 colors. I could get 1024x768 if the monitor allowed it.
I could get 64K colors (16-bit) if XFree86 allowed it. This is a
limitation not of the hardware, not exactly of Linux, but of the XFree86
people who don't wish to take the trouble to support the inexpensive
cards on the market.
<P>
My present (Oak) card seems to be limited to 8-bit color in any
event, my other (Cirrus Logic) card will support 16-bit and 24-bit
color, which if fully supported would allow me 64K colors at 800x600 or
16M colors at 640x480 (with a virtual 800x600 window).
<P>
The people at XFree86 (one of them a Cirrus employee) have, by their
own statement, chosen to spend their time on the latest and greatest
cards, with the older, cheaper cards going by the board.
<P>
I have tried and failed to get the necessary information from Cirrus
Logic to rewrite the XFree driver to better use the card.
<blockquote> <I>
Now mind you, I don't cringe on sharing the best O/S on the planet, In
fact I want everyone to use Linux.
It's just that almost all X windows software is written for 1024 X 768
or higher resolution video screens and that 99% of those wanting to
use Linux and X windows only have a 14" monitor that can barely get
past 640X480 at 256 colors.
</I> </blockquote>
See above. For a cost of no more than $50 they should be able to get a
1MB video card that will handle *much* better resolution.
<blockquote> <I>
I tried several times to get friends into Linux and X but to no avail
because the software developed for X is for those that have Gobs of
money for good video boards and humoungous monitors.
It's not a limitation of Linux or X, it that the software that is
developed for these platforms are by professionals or professional
users that can afford that new 21 inch monitor at the computer store.
</I> </blockquote>
You might try pushing different programs. My main problem (except with
viewers for Adobe file formats) is getting *multiple* windows on the
screen at once. Also, certain *types* of applications, by their very
nature, demand lots of screen real estate. An application of that sort
is going to be cramped on a small screen *regardless* of underlying OS
support. I simply avoid such applications until I can acquire a larger
screen (about $500, locally).
<blockquote> <I>
We as a group might want to see software scaled back to the 640X480
crowd.. then Linux would take the world by storm.. Until then It's
going to be limited to us pioneers and Scientists...
</I> </blockquote>
Actually, the *biggest* barrier to using Linux X Apps is that so many of
them are written using Motif! That's almost as bad as WinDoze.
<P>
--Buz Cory :)
<P> <hr> <P>
<!--================================================================-->
<center>Published in <i>Linux Gazette</i> Issue 27, April 1998</center>
<!--====================================================================-->
<P> <hr> <P>
<A HREF="./index.html"><IMG SRC="../gx/indexnew.gif" ALT="[ TABLE OF
CONTENTS ]"></A>
<A HREF="../index.html"><IMG SRC="../gx/homenew.gif" ALT="[ FRONT
PAGE ]"></A>
<A HREF="./lg_tips27.html"><IMG SRC="../gx/fwd.gif" ALT=" Next "></A>
<P>
<h5>This page written and maintained by the Editor of <I>Linux Gazette</I>,
<A HREF="mailto: gazette@ssc.com">gazette@ssc.com</A><BR>
Copyright &copy; 1998 Specialized Systems Consultants, Inc. </H5>
<P>
<H4>"Linux Gazette...<I>making Linux just a little more fun!</I>"
</H4>
<P> <hr> <P>
<!-- QUICK TIPS SECTION ================================================== -->
<center>
<H1><A NAME="tips"><IMG ALIGN=MIDDLE ALT="" SRC="../gx/twocent.gif">
More 2&#162; Tips!</A></H1> <BR>
Send Linux Tips and Tricks to <A HREF="mailto:gazette@ssc.com">
gazette@ssc.com
</A></center>
<p><hr><p>
<H3>Contents:</H3>
<ul>
<li><a HREF="./lg_tips27.html#shane">Re: Help Wanted LaserJet 4L</a>
<li><a HREF="./lg_tips27.html#fraser">StarOffice 4/Ghostscript</a>
<li><a HREF="./lg_tips27.html#rc">Linux and VAX 3400 and 3300</a>
<li><a HREF="./lg_tips27.html#caolin">xdm with Pictures</a>
<li><a HREF="./lg_tips27.html#caolin2">Re: Help-Installing Linux on a FAT32</a>
<li><a HREF="./lg_tips27.html#john">Regarding Easter Eggs in Netscape etc.</a>
<li><a HREF="./lg_tips27.html#craige">Re: Changing XDM windows</a>
<li><a HREF="./lg_tips27.html#serge">Nice xdm and Linux PPC</a>
<li><a HREF="./lg_tips27.html#roland">Re: Help with Sound Card</a>
<li><a HREF="./lg_tips27.html#friedhelm">Modline for TV</a>
<li><a HREF="./lg_tips27.html#ji">mpack 2 cent tip</a>
<li><a HREF="./lg_tips27.html#guido">shutdown and root</a>
<li><a HREF="./lg_tips27.html#allan">Perl Script 2 cent tip</a>
<li><a HREF="./lg_tips27.html#james">RE: my dual pentium</a>
<li><a HREF="./lg_tips27.html#james2">RE: Changing XDM windows</a>
<li><a HREF="./lg_tips27.html#james3">RE: HELP-Installing Linux on a FAT32
Drive</a>
<li><a HREF="./lg_tips27.html#gman">Re: Apache SSL extensions...</a>
<li><a HREF="./lg_tips27.html#brett">Reply to locate tip (LG 26)</a>
<li><a HREF="./lg_tips27.html#milton">Re: Getting Linux to the public...</a>
<li><a HREF="./lg_tips27.html#carl">My 2-cents on W95/Linux coexistence</a>
<li><a HREF="./lg_tips27.html#christoph">2-cent tips in LG 26: core dumps</a>
<li><a HREF="./lg_tips27.html#mark">Perl Script 2C Tip</a>
<li><a HREF="./lg_tips27.html#john2">rxvt 0.02$ tip</a>
<li><a HREF="./lg_tips27.html#john3">Tiny patch to ifconfig</a>
<li><a HREF="./lg_tips27.html#bill">Re: Wanting HELP!</a>
<li><a HREF="./lg_tips27.html#kragen">Re: Help Wanted (usershell on console
without logging in)</a>
<li><a HREF="./lg_tips27.html#vivek">2 cent tip followup -- X</a>
<li><a HREF="./lg_tips27.html#remco">locate patch</a>
<li><a HREF="./lg_tips27.html#padraig">locate subdirectories</a>
</ul>
<P> <hr> <P>
<!--================================================================-->
<a name="shane"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
RE: Help Wanted - LaserJet 4L
</H3>
<P>
Date: Mon, 2 Mar 1998 14:38:43 -0500<BR>
From: <A
HREF="mailto:Shane_McLaughlin@stream.com">Shane_McLaughlin@stream.com</A>
<P>
To: John.H.Gorman@MCI.Com<BR>
Re: font sizes + points, Linux Gazette #26
I had a similar problem with an old Deskjet under SunOS and was
supplied with the following info by HP support Europe. It applies to
DOS but should be applicable to any Un*x system as well
These are printer instruction generation wizards URLs
<ul>
<li>FOR PCL3 got to (DeskJets):
http://www.hp.com/cpso-support/deskjet/tools/pcl3.html
<li>FOR PCL5 got to (LaserJets):
http://www.hp.com/cpso-support/PrinterLanguage/pclwiz.html
<li>FOR PJL go to (printer job language - like a batch language):
http://www.hp.com/cpso-support/PrinterLanguage/pjlwiz.html
<li>Try checking entries on Horizontal Motion Index and Vertical Motion
Index (HMI + VMI) - that might be what you want.
</ul>
I saw a posting in C.O.L.A. a few months back that someone has
already done the tough work and has programmed some mostly-complete
PCL 3+ 5 drivers for Linux
If all else fails, HP DOS drivers exist that can customise point sizes
+ fonts and save them permanently to printer memory (5Si's do, i don't
know about 4Ls) If you don't have a DOS partition maybe DOSEMU?
Good Luck!<BR>
Shane McLaughlin
<P> <hr> <P>
<!--================================================================-->
<a name="fraser"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
2c tip (StarOffice 4 / Ghostscript)
</H3><P>
Date: Mon, 2 Mar 1998 18:48:51 -0500 (EST)<BR>
From: Fraser McCrossan, <A
HREF="mailto:fraserm@gtn.net">fraserm@gtn.net</A>
<P>
I've just started using the excellent Star Office 4.0 (free for personal
use - go get it now!), but have noticed that when using Ghostscript to
filter its print output on my non-Postscript printer, the results
were not quite as they appeared on the screen.
<P>
I reasoned that this might be because the fonts supplied with SO didn't
quite match those supplied with Ghostscript. However, the SO fonts are
Type 1 Postscript fonts... which Ghostscript can use. To make Ghostscript
use them, you need to link them to its home directory. For example, if
your SO is installed in /home/fraser/Office40, change to the Ghostscript
font (normally /usr/local/share/ghostscript/fonts) directory, and do the
following:
<PRE>
ln -s /home/fraser/Office40/fonts/type1/*.pf[ab] .
mv Fontmap Fontmap.hide
</PRE>
For some reason, when I tried to add the new fonts to Fontmap in the same
format as the existing fonts, GS would crash, hence hiding it. I'm not a
GS guru... perhaps someone else can explain why. However, GS works just
fine without Fontmap for me, although it probably takes longer to start
up - and everything I print looks just like the screen.
<P>
--Fraser
<P> <hr> <P>
<!--================================================================-->
<a name="rc"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
RE: Linux and VAX 3400 and 3300
</H3><P>
Date: Mon, 02 Mar 1998 20:34:55 -0500<BR>
From: RC Pavlicek, <A HREF="mailto:pavlicek@radc17.cop.dec.com">
pavlicek@radc17.cop.dec.com</A>
<P>
The March issue of the Gazette includes the following under 2 Cent Tips:
&lt;&lt;I have just purchased a MicroVAX 3400 and 3300. I would like to put
&lt;&lt;Linux on these two systems. Can you provide any help in this aspect.
<P>
&lt;I believe those are MIPS 3000 boxes, try the Linux VAX Port Homepage at >http://ucnet.canberra.edu.au/~mikal/vaxlinux/home.html
&lt;and the Linux/MIPS project at http://lena.fnet.fr/
<P>
Anything with "VAX" in its name is just that -- a VAX. Digital made
MIPS boxes once upon a time, but they never used the VAX/MicroVAX
name. Most of Digital's MIPS boxes were sold under the DECstation or
DECsystem name.
<P>
The pointer to the VAX/Linux effort is the best one I know about, but
the whole VAX/Linux project was not even close to producing usable code
last time I checked. NetBSD, if it works on these boxes, may be your
best bet.
<P>
-- Russell C. Pavlicek<BR>
[speaking for himself, not for Digital Equipment Corporation]
<P> <hr> <P>
<!--================================================================-->
<a name="caolin"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
xdm with pictures
</H3><P>
Date: Thu, 05 Mar 1998 10:34:43 -0000 (GMT)<BR>
From: Caolan McNamara, <A HREF="mailto:Caolan.McNamara@ul.ie">
Caolan.McNamara@ul.ie</A>
<P>
<blockquote>
Can I change the XDM login window/screen? I have a cool house logo so i want to
use it in my own Home Network.
And at my school they want to know to so. Is it possible. If yes, how? If no,
WHY NOT? -- Jeroen Bulters, The netherlands
</blockquote>
you could try xdm3d_xpm, which allows a picture in the xdm box, which is 3d
with shadows and stuff,one version is at
ftp://brain.sel.cam.ac.uk/users/mbm/xdm3d (probably the latest)
theres another (older) at
http://oak.ece.ul.ie/~griffini/software.html
<P> <hr> <P>
<!--================================================================-->
<a name="james3"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Re: HELP-Installing Linux on a FAT32 Drive
Date: Thu, 05 Mar 1998 11:35:42 -0000 (GMT)<BR>
</H3><P>
From: Caolan McNamara, <A HREF="mailto:Caolan.McNamara@ul.ie">
Caolan.McNamara@ul.ie</A>
<blockquote>
I'm interested in installing linux on a machine I built recently, but when I
installed Win95(b), I idiotically opted to
format the drive using FAT32, which in a 95-only environment is great, but
Linux can't read it for greek.
I've looked around for utilities to effectively un-FAT32 the drive, which I
will then partition with Partition Magic to
use the freespace as a native ext2 partition, etc., but am having little luck.
Reformating is a disheartening prospect
I would rather not face, but am fully prepared to do so if I don't find any
help here. --nate daiger</blockquote>
<P>
Well partition magic 3 can repartition fat32 without hassle, and there exists
a patch for linux kernel to understand fat32 at
http://bmrc.berkeley.edu/people/chaffee/fat32.html
which also lists a version of fips which also should understand fat32, to
resize your drive.
<P> <hr> <P>
<!--================================================================-->
<a name="john"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Regarding "Easter Eggs" in Netscape etc.
</H3><P>
Date: Thu, 5 Mar 1998 23:21:20 +0000 (GMT)<BR>
From: John Pelan, <A
HREF="mailto:johnp@am.qub.ac.uk">johnp@am.qub.ac.uk</A>
<P>
The on-going 2 cent tips about the hidden "Easter Eggs" in Netscape is
interesting. However rather than continually listing them it might be more
fruitful to learn how one can try to discover them for oneself.
<P>
One useful tool in particular, is the oft neglected 'strings' command.
This will locate printable strings in an arbitrary file and display them.
So one can do something like;
<PRE>
prompt% strings /usr/lib/netscape/netscape-navigator
</PRE>
which will reveal all the embedded strings in that binary. You might like
to redirect the output to a file for analysis. As many of the strings will
be rubbish (i.e. 'random' sequences of printable characters) one can
always use grep, awk, Perl etc. to help filter in/out particular patterns.
<P>
In the case of Netscape, only a tiny set of the strings will correspond to
"Easter Eggs" (not all of them will be immediately obvious either) and
locating them is left as an exercise to the reader...
<P> <hr> <P>
<!--================================================================-->
<a name="craige"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Re: Changing XDM windows
</H3><P>
Date: Fri, 06 Mar 1998 12:16:02 +1200<BR>
From: Craige McWhirter, <A HREF="mailto:craige@magna.com.au">
craige@magna.com.au</A>
<blockquote>
From: Jeroen Bulters, jbulters@scoutnet.nl <BR>
Can I change the XDM login window/screen? I have a cool house logo so i want
to use it in my own Home Network. And at my school they want to know to so.
Is it possible. If yes, how? If no, WHY NOT. </blockquote>
<P>
Try this web site below. It had everything I needed to
customise my XDM login.<BR>
<A HREF="http://torment.ntr.net/xdm/">http://torment.ntr.net/xdm/</A>
<P> <hr> <P>
<!--================================================================-->
<a name="serge"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Nice xdm and Linux PPC
Date: Fri, 06 Mar 1998 09:09:48 -0500<BR>
</H3><P>
From: Serge Droz, <A
HREF="mailto:droz@physics.uoguelph.ca">droz@physics.uoguelph.ca</A>
<P>
just a quick comment on two letters in the Linux Gazette #26
(http://www.linuxgazette.com/issue26/lg_mail26.html)
<ol>
<li>Changing XDM windows: Check out
http://jovian.physics.uoguelph.ca/~droz/uni/xdm3d.html for
a replacement (This version comes with pam support). This
version runs fine on our Redhat systems (Intel & PPC).
<P>
<li>New direction: Linux is beeing ported to the PPC chip. See
http://www.linuxppc.org for more info, downloads CD's T-shirts....
It actually runs quite stable on my PPC.
</ol>
Cheers, Serge
<P> <hr> <P>
<!--================================================================-->
<a name="roland"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Re: Help with Sound Card
</H3><P>
Date: Fri, 6 Mar 1998 20:32:13 +0100 (MET)<BR>
From: Roland Smith, <A HREF="mailto:rsmit06@ibm.net">
rsmit06@ibm.net</A>
<P>
According to the Sound-HOWTO:<BR>
"MV Jaz16 and ESS688/1688 based cards generally work with the
SoundBlaster driver"
<P>
To get a PnP card to work, you need to configure it first. There are two
ways of doing that:
<ol>
<li>boot into DOS, use the card's DOS-based initialization program, then do
a warm boot to Linux
<P>
<li>compile sound support as a module, and use isapnp from the isapnptools
package to initialize the card, after which you can insert the sound
module.
</ol>
The isapnptools package can be found at
ftp://ftp.demon.co.uk/pub/unix/linux/utils
<P>
Regards, Roland
<P> <hr> <P>
<!--================================================================-->
<a name="friedhelm"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Modline for TV
</H3><P>
Date: Sun, 8 Mar 1998 13:11:37 +0100 (MET)<BR>
From: <A HREF="mailto:friedhelm.mehnert@gmx.net">
friedhelm.mehnert@gmx.net</A>
<P>
I have shamelessly stolen this from USENET, because I feel this excellent
information should appear within the <I>Linux Gazette</I>.
<P>
I hope the original author don't mind. :-)
<blockquote>
From: Rob van der Putten<BR>
Date: Sun, 8 Mar 1998 00:14:15 +0100<BR>
Hopefully you won't need this, but if you ever want to display X on a big
screen and a TV is the only big screen around you might want to use this.
</blockquote> <P> <blockquote>
A TV with a RGB SCART input is nothing more than a fixed sync monitor with
a rather low picture quality. This means that you can make a TV compatible
signal with a plain vanilla cheapo VGA card.
</blockquote> <P> <blockquote>
For the european 625 line (575 visable lines) TV standard a modeline looks
like this:
Modeline "736x575i" 14.16 736 760 824 904 575 580 585 625 interlace -hsync -vsync
</blockquote> <P> <blockquote>
Officially the horizontal resolution is 767 (4 / 3 * 575) pixels with a
clock of 14.76 MHz. However, since the clock used is 14.16 MHz, I reduced
the horizontal values proportional to 14.16 / 14.76 (and rounded them to
the nearest multiple of 8).
</blockquote> <P> <blockquote>
If you want to make a 640x480 screen with a black border you can you use
this line:
Modeline "640x480i" 14.16 640 712 776 904 480 532 537 625 interlace -hsync -vsync
</blockquote> <P> <blockquote>
You can center it by altering the 2nd and 3rd horizontal and vertical
values (this example shifts the picture to the left):
Modeline "640x480i" 14.16 640 728 792 904 480 532 537 625 interlace -hsync -vsync
</blockquote> <P> <blockquote>
You can make a non interlaced signal with this modeline:
Modeline "736x288" 14.16 736 760 824 904 288 290 292 312 -hsync -vsync
</blockquote> <P> <blockquote>
The VGA RGB signals are compatible with the scart bus, the sync signals
are not. You have to create a composit sync signal of 0.3 ... 0.5 Vpp.
The cirquit below acts both as a AND gate and a level translator.
It doesn't need a power supply and can be mounted inside a VGA plug:
</blockquote> <PRE>
-VS ------------------------+
|
|
| /
+-----+ |/
-HS --+ 3k3 +-----*-----| BC 548 B
+-----+ | |\
| | \|
| -| +-----+
| *-----+ 68 +----- -CS 0.3 Vpp
| | +-----+
+++ +++
| | | |
| | | |
+++ +++
| |
GND --------------*---------*----------------- GND
1k2 820
</PRE> <blockquote>
You can use any general purpose low frequent low power NPN transistor
instead of the BC 548 B<BR>
Regards, Rob
</blockquote>
<P> <hr> <P>
<!--================================================================-->
<a name="ji"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
mpack 2 cent tip
</H3><P>
Date: Mon, 9 Mar 1998 11:17:47 +0100 (MET)<BR>
From: J.I.vanHemert, <A HREF="mailto:jvhemert@wi.leidenuniv.nl">
jvhemert@wi.leidenuniv.nl</A>
<P>
I response to the 2 cent tip of Ivan Griffin, I am sending a two cent tip of
my own.
<P>
Ivan send in a script that can be used to mail Micro$oft users. I would like
to mention the package 'mpack', this program is very handy if you want to send
out some mime-encoded mail. Furthermore the package also contains 'munpack'
which does the obvious thing.
<P>
Mpack can be found on ftp.andrew.cmu.edu in the directory pub/mpack, in the
archive mpack-1.5.tar.gz
<P>
Cheer, Jano
<P> <hr> <P>
<!--================================================================-->
<a name="guido"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
shutdown and root
</H3><P>
Date: Mon, 9 Mar 1998 13:10:55 +0100<BR>
From: Guido Socher, <A HREF="mailto:eedgus@eed.ericsson.se">
eedgus@eed.ericsson.se</A>
<P>
I noticed that many people still login as root before they power
down their system in order to run the command 'shutdown -h now'.
This is really not necessary and it may cause problems if everybody
working on a machine knows the root password.
<P>
Most Linux distributions are configured to reboot if ctrl-alt-delete
is pressed, but this can be changed to run 'shutdown -h now'.
Edit your /etc/inittab and change the line that starts with ca:
<PRE>
# Trap CTRL-ALT-DELETE
# original line would reboot:
#ca::ctrlaltdel:/sbin/shutdown -t3 -r now
# now halt the system after shutdown:
ca::ctrlaltdel:/sbin/shutdown -t3 -h now
#
</PRE>
Now you can just press crtl-alt-delete as normal user and your system
comes down clean and halts.
<P> <hr> <P>
<!--================================================================-->
<a name="allan"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Perl Script 2 cent tip (maybe even a nickel)
</H3><P>
Date: Mon, 09 Mar 1998 18:37:20 -0500<BR>
From: Allan Peda, <A
HREF="mailto:allan@interport.net">allan@interport.net</A>
<P>
When I was putting my network card in my Linux box, I wanted to keep the
soundblaster, but the addresses are not easy to read (for me) in hex.
Even if there were in decimal, I figured a plot of the areas that appear
open would be useful. So I hacked together a little perl script to do
just that, Usage: addreses.pl addr.txt > outputfile.txt
<P>
Of course it goes to stdout without a redirected file.
The input file is constructed with one line for each address:
<PRE>
base_address TAB upper_address TAB :Description
</PRE>
Here's a little perl script that I wrote to help me identify
conflicting addreses:
<PRE>
# address.pl v 0.1
# Allan Peda
# allan@interport.net
#
# How to use: Prepare a file based on the format of the sample at
# the end of this script.
# This script will plot a servicable chart of the addresses in use,
# with the gaps plainly apparant.
#
$debug = 1;
$min_addr=0;
$max_addr=0;
for ($i=1; &lt:&gt;; $i++) {
/^(\w+)\s/; $$memory[$i]{base_addr}=$1; # base address
/^\w+\s+(\w+)\s/; $$memory[$i]{upper_addr}=$1; # upper address
/\:(.+)$/; $$memory[$i]{addr_descrip} = $1; # description of address
$ttl_num_addresses = $i;
print "$i\t $$memory[$i]{base_addr} \t" if $debug;
print hex($$memory[$i]{base_addr}),"\t-->\t" if $debug;
print " $$memory[$i]{upper_addr}\t" if $debug;
print hex($$memory[$i]{upper_addr}),"\t" if $debug;
print "$$memory[$i]{addr_descrip}\n" if $debug;
if (( hex($$memory[$i]{base_addr}) < hex($min_addr) ) || $i<=1){
$min_addr = $$memory[$i]{base_addr};
}
if (( hex($$memory[$i]{upper_addr}) > hex($max_addr) ) || $i<=1){
$max_addr = $$memory[$i]{upper_addr};
}
}
print "\nTotal number of addreses used = $ttl_num_addresses" if $debug;
print "\nMinimimum address is: $min_addr" if $debug;
print "\nMaximimum address is: $max_addr\n" if $debug;
for ($addr = hex($min_addr); $addr <= hex($max_addr); $addr++) {
printf "\n%4x -> ", $addr;
for ($i=1; $i <= $ttl_num_addresses; $i++) {
if (( hex($$memory[$i]{base_addr}) <= $addr ) and
(( hex($$memory[$i]{upper_addr}) >= $addr))){
print "*** ";
if (( hex($$memory[$i]{base_addr}) == $addr )) {
print "$$memory[$i]{addr_descrip}";
}
}
}
}
# sample file address.txt follows:
__END__
0x1F0 0x1f8 :Hard disk drive
0x200 0x207 :Game I/O
0x278 0x27f :Parallel Port 2 (LPT2)
0x2e8 0x2ef :serial port, com4
0x300 0x31f :Prototype / Network PCB
0x360 0x363 :PC Network (Low address)
0x368 0x36B :PC Network (High address)
0x378 0x37f :Parallel Port 1 (LPT1)
0x380 0x38f :SDLC, Bisync
0x3a0 0x3bf :MDA / prn adapter (hercules)
0x3c0 0x3cf :EGA/VGA
0x3d0 0x3df :CGA/MDA/MCGA
0x3e8 0x3ef :Diskette controller
0x3fb 0x3ff :serial port 1 - com 1
</PRE>
The input file looks like this (typically):
<PRE>
0x1F0 0x1f8 :Hard disk drive
0x200 0x207 :Game I/O
0x278 0x27f :Parallel Port 2 (LPT2)
0x2e8 0x2ef :serial port, com4
0x300 0x31f :Prototype / Network PCB
0x360 0x363 :PC Network (Low address)
0x368 0x36B :PC Network (High address)
0x378 0x37f :Parallel Port 1 (LPT1)
0x380 0x38f :SDLC, Bisync
0x3a0 0x3bf :MDA / prn adapter (hercules)
0x3c0 0x3cf :EGA/VGA
0x3d0 0x3df :CGA/MDA/MCGA
0x3e8 0x3ef :Diskette controller
0x3fb 0x3ff :serial port 1 - com 1
</PRE>
<P> <hr> <P>
<!--================================================================-->
<a name="james"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
RE: my dual pentium
</H3><P>
Date: Mon, 09 Mar 1998 10:29:24 -0700 <BR>
From: James Gilb, <A HREF="mailto:p27451@email.sps.mot.com">
p27451@email.sps.mot.com</A>
<P>
My guess is that the default Caldera kernel does not have multiple
CPU's enabled. You will probably have to recompile your kernel to
enable SMP. Some kernel versions (even the 2.0.xx) are less stable for
SMP than others, unfortunately I can't give you any help on which
version to choose. However, you may want to join the Linux-SMP mailing
list, email majordomo@vger.rutgers.edu with the text 'subscribe
linux-smp' to join the list. An archive is maintained at Linux HQ
(http://www.linuxhq.com/lnxlists/linux-smp/), so you may want to look
there first before you ask on the mailing list. The May 1997 Caldera
newsletter has the following information (a little out of date):
<P>
Linux? When will
SMP be fully supported?
<P>
The Linux 2.x kernel with full SMP support is currently in beta,
and will most likely
be included in the next stable release of the kernel. The Linux
2.0.25 and 2.0.29
kernels which ship in OpenLinux 1.0 and 1.1 products can reside
and are tolerant of an
SMP environment, but will not perform load balancing.
<P>
To enable SMP, the OpenLinux 1.2 FAQ
(http://www.caldera.com/tech-ref/col-1.2/faq/faq-5.html) has the
following suggestions:
<P>
5.4 How to enable SMP (multiple processor) support: <BR>
To enable SMP (multiple processor) support in OpenLinux, you
must do three things:
<ol>
<li>Go to "/usr/src/linux" and uncomment the "SMP = 1"
line in the Makefile (to
uncomment this line, remove the preceeding "#").
<li>Follow the instructions in Rebuilding the Linux Kernel
for Caldera OpenLinux 1.2
(http://www.caldera.com/tech-ref/docs/COL12-Kernel-Rebuild.html)
and during the 'make config' step be sure to enable
"Real-time clock support". Then
recompile your kernel using the remainder of the
steps.
<li>Reboot your system.
</ol>
Currently there is no method for monitoring how much of each
processor is being used, but if you run the "top" utility you will most
likely see processes that are using more than 100% of a processor;
whatever is above the 100% mark is being done with the other processors.
Also, to determine if both processors have been detected and are in use,
you can cat the "/proc/cpuinfo" file for a report of what processors are
recognized by Linux; if there's more than one listed, you are running
with SMP support.
<P>
Some sources for information on SMP are:<BR>
<P>
http://www.caldera.com/LDP/HOWTO/Parallel-Processing-HOWTO-2.html<BR>
(or any other LDP site)<BR>
http://www.linux.org.uk/SMP/title.html <BR>
http://www.uruk.org/~erich/mps-linux-status.html <BR>
(These pages haven't been updated in a while)
<P>
If after reading the above information, you still have questions, you
might email Caldera's technical support (assuming you purchased your
distribution from them and registered it.) I have had good luck with
their technical support, but read the FAQ's first.
<P>
BTW: I found most of the above information by going to Caldera's web
page and typing SMP in the search box. Thanks Caldera for the web site.
<P>
James P. K. Gilb
<P> <hr> <P>
<!--================================================================-->
<a name="james2"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
RE: Changing XDM windows
</H3><P>
Date: Mon, 09 Mar 1998 11:20:33 -0700<BR>
From: James Gilb, <A HREF="mailto:p27451@email.sps.mot.com">
p27451@email.sps.mot.com</A>
<P>
Jeroen, there a three ways that I know for sure to customize your login
screen.
<ol>
<li>Get XDM-photo from
ftp://tsx-11.mit.edu/pub/linux/sources/usr.bin.X11/xdm-photo-1.1.tar.gz
<li>Use XBanner, which can do some really terrific things with you
login screen. If you want a login screen that is the envy of you
neighbors, you need XBanner. The URL for XBanner is:
http://chaos.fullerton.edu/XBanner
<li>Use Xdm3d/XPM - from
http://oak.ece.ul.ie/~griffini/software.html, get the sources and put
your own XPM in, although the default penguin is pretty cool.
</ol>
-- James Gilb
<P> <hr> <P>
<!--================================================================-->
<a name="james 3"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
RE: HELP-Installing Linux on a FAT32 Drive
</H3><P>
Date: Mon, 09 Mar 1998 11:24:56 -0700<BR>
From: James Gilb, <A HREF="mailto:p27451@email.sps.mot.com">
p27451@email.sps.mot.com</A>
<P>
Nate, there is a patch to allow FAT32 support in the Linux kernel so you
can mount the OSR2 drives and even run a umsdos type installation. The
web page for the patches is:<BR>
http://bmrc.berkeley.edu/people/chaffee/fat32.html
<P>
-- James Gilb
<P> <hr> <P>
<!--================================================================-->
<a name="gman"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Re: Apache SSL extensions...
</H3><P>
Date: Wed, 11 Mar 1998 02:45:06 -0800<BR>
From: G-man, <A HREF="mailto:gman@infinex.com">gman@infinex.com</A>
<P>
I've put up a web page on how to setup apache-ssl Check out
http://www.linuxrox.com/WebServer.html .. Also have examples of how the
httpd.conf should look like to run secure and non-secure web server
using apache-ssl..
<P>
Hope that helps..
<P> <hr> <P>
<!--================================================================-->
<a name="brett"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Reply to locate tip (LG 26)
</H3><P>
Date: Wed, 11 Mar 1998 19:37:47 -0500 (EST)<BR>
From: Brett Viren, <A HREF="mailto:bviren@ale.physics.sunysb.edu">
bviren@ale.physics.sunysb.edu</A>
<P>
About the problem of `locate' (2c tip #2 LG #26) showing files that
normal users can't access: If this happens, it is not a bug with
`locate' but rather with the Linux distribution (or the way locate and
friends have been installed by hand). `Locate' should be allowed to
print any and all matching file that are in the database it is pointed
to. However, in the case of the database for general system, it is a
security bug (IMO) if the database includes non-world-readable
files. Here is were the problem lies.
<P>
Debian Linux handles this by running `updatedb' (the program which
actually makes the `locate' data base) from /etc/cron.daily/find via:
<PRE>
cd / && updatedb --localuser=nobody 2>/dev/null
</PRE>
This is also a tad easier than patching/recompiling.
Anyways, there is my 2cents.
<P>
-Brett.
<P> <hr> <P>
<!--================================================================-->
<a name="milton"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Re: Getting Linux to the public...
</H3><P>
Date: Thu, 12 Mar 1998 17:19:59 -0500<BR>
From: Milton L. Hankins {64892}, <A HREF="mailto:mlh@swl.msd.ray.com">
mlh@swl.msd.ray.com</A>
<P>
(This is in response to the article posted in General Mail, Linux
Gazette, Issue 26, March 1998.)
<P>
Although I can't speak for developers "that have Gobs of money for good
video boards and [humongous] monitors," I can share a few things with
you about my experiences with XFree86. I have run it successfully with
on a 14 inch monitor, using the standard SVGA X server on a 486-75MHz
with a Cirrus video card. It took quite a bit of fiddling, but I
eventually figured out how to get it to run in 800x600 mode, and then in
1024x768 interlaced.
<P>
A lot of it was just meddling with the XFree86 configuration file
directly, hoping that I wouldn't blow my monitor up. There are tools
today (like Metro-X) that make this process a fair bit easier.
<P>
One thing you might not realize is that the XFree86 config (last I
remember) sometimes chooses 640x480 mode on startup, when it actually
supports more modes. Try pressing Ctrl-Alt-Keypad+ to change the
resolution while running X.
<P>
Monitor size is another matter. I recall one application that liked to
size itself bigger than my screen. There are a couple ways around this.
<P>
The first is the -geometry flag, available to most X applications. If
you want to try it, the xterm, xeyes, and xbiff programs all support it.
The most basic format is:
<PRE>
-geometry =&lt;width&gt;x&lt;height&gt;+&lt;x&gt;+&lt;y&gt:
</PRE>
Replace &lt;width&gt; and &lt;height&gt; with the desired width and height
of the
window, respectively. Sometimes width and height refer to characters,
and sometimes they refer to pixels. Your mileage may vary. &lt;x&gt; and
&lt;y&gt;
refer to the pixel coordinates of the new window's upper left corner.
If you want, you can leave out the first half (default size) or the
second half (default location). Sometimes you can leave off the equals
sign, too.
<P>
Some examples: "-geometry 800x600+0+0" will place an 800x600 window in
the upper left corner of the screen. "-geometry 400x300+200+150" will
place a 400x300 window in the center of an 800x600 display.
<P>
You can write shell aliases to run these programs with a default size.
A cleaner way is to put geometry specifications in your .Xresources
file. Usually this is of the form
&lt;programName&gt;*geometry:
&lt;width&gt;x&lt;height&gt;+&lt;x&gt;+&lt;y&gt;
<P>
Here are some examples:
<PRE>
XEyes*geometry: +1060+40
plan*geometry: +10+10
Netscape.Navigator.geometry: =336x425
Netscape.Mail.geometry: =300x400
Netscape.News.geometry: =300x400
Netscape.Composition.geometry: =350x350
</PRE>
You may also want to adjust the fonts for your program, especially if it
doesn't support the -geometry flag nor X resource.
<P>
I, too, feel that Linux is not ready for the public because of its
comparatively steeper learning curve. But it's gotten a lot better over
the years, thanks to the Linux community. Keep up the good work,
everyone!
<P>
Milton L. Hankins (no known relation to Greg)
<P> <hr> <P>
<!--================================================================-->
<a name="carl"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
My 2-cents on W95/Linux coexistence
</H3><P>
Date: Tue, 17 Mar 1998 17:56:16 -0500<BR>
From: Carl Helmers, <A HREF="mailto:carl@helmers.com">
carl@helmers.com</A>
<P>
Re W95 and Linux: With hard disks crashing in price (hopefully not the
heads), here is the strategy I used for this problem of getting W95 and
Linux on the same machine at the end of 1997: On one of my personal
desktop machines, I had excellent results using a product called "System
Commander" -- this product has a Linux-savvy manual which explains all
the details one needs. The machine in question is a generic Pentium-133
with 32mb memory, a 2GB EIDE drive and a S3 Virge based graphic card.
After I got the machine in 1997 I added a removable 2GB EIDE drive in a
DataPort drive frame/cartridge setup for testing various Linux versions,
keeping the original W95 that came with the machine in the first drive.
<P>
Once I installed System Commander I set up the default boot choice on
the P133 desktop machine to be (of course) Linux on the second hard
drive, where I currently have X installed. I use this machine (running
Emacs and a bunch of handy macros) to keep my update log while
installing new Linices on my other machines (a Dell Latitude LM Laptop
[P133 40mb] with an alternate 2GB hard drive for Linux, and a Cyrix
6X86-166 clone on the desktop next to the P133.
<P>
My first attempt at a W95/Linux combination was on that Cyrix clone --
whose W95 seems to have re-written the fundamental hard disk sector map
of the second (but different model number, same capacity) Western
Digital drive on which I installed Linux through getting a working X
display -- before closing down and rebooting with LILO. After that
disaster, I just said the heck with W95 and reformatted the 2GB hard
disk as the primary Linux disk, with the second disk in its DataPort
removable frame retained as an additional file storage region. In my 30
years of using computers since high school in 1966, I have developed
the habit of always keeping a detailed log when doing anything I might
want to reproduce -- such as installing a Linux release. That way, if
I make a mistake I can try again, changing some critical detail or
other. I started the habit with pencil and spiral paper notebooks.
These days, I use a second computer system sitting on the same desktop
running emacs under XFree86 with my custom macros to speed up entry --
but the principle is the same.
<P>
In the System Commander desktop machine, I set W95 as a second boot
option, and the third option for booting from floppy using the Linux
installation boot diskettes. I still useW95 [perish the thought] for
one or two commercial Wintel programs I like which do not have a Linux
work-alike, and to try out new software packages.
<P>
Carl Helmers
<P> <hr> <P>
<!--================================================================-->
<a name="christoph"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
2-cent tips in LG 26: core dumps (Marty Leisner)
</H3><P>
Date: Tue, 17 Mar 1998 19:45:48 +0100<BR>
From: Christoph L. Spiel, <A
HREF="mailto:Christoph_Spiel@physik.tu-muenchen.de">
Christoph_Spiel@physik.tu-muenchen.de</A>
<P>
I was annoyed by "file", too. Under several other unices
"file" can be used to identify a core dump. Marty's tip is
just fine. You don't have to write any script or other stuff.
<P>
I used "gdb" to find out where a "core"-file came from. As
a wrapper around it, I wrote "idcore". It has
the advantage of displaying only relevant information, i.e.,
the name of the binary causing the core-dump. This way it
can by used, e.g., in cron jobs to notify users.
The verbosity of idcore is controlled with the
<PRE>
--brief
</PRE>
and
<PRE>
--long
</PRE>
options.
<P>
I'd like to paste some sample output here, but neither can I
find a core dump on my machine, nor do I know a program that
generates one. (This is not a devine linux-box, I have
thrown out most instable binaries ;-)
<P>
Here comes "idcore":
<PRE>
#!/bin/sh
# name: idcore -- identify which binary caused a core dump
# author: c.l.s. (cspiel@physik.tu-muenchen.de)
# last rev.: 1998-01-22 11:14
# bash ver.: 1.14.7(1)
# $Id: issue27.html,v 1.3 2003/02/03 21:50:18 lg Exp $
# display help message
# char* disp_help(void)
function disp_help
{
echo "usage:"
echo " idcore [OPTION] [[COREDUMP] ...]"
echo
echo " If COREDUMP is omitted the core file in the current"
echo " directory is used."
echo
echo " -h, --help display this help message"
echo " -v, --version show version of idcore"
echo " -b, --brief brief format, i.e. filename only"
echo " -l, --long long format, with filename, signal, user,"
echo " date, and backtrace"
}
# retrieve name binary that caused core dump via gdb
# char* get_name(const char* mode, const char* name)
function get_name
{
case "$1" in
brief)
echo q | gdb --quiet --core="$2" 2>&1 | head -1 | \
sed -ne "s/^.*\`\(.*\)'\.$/\1/p"
;;
standard)
echo q | gdb --quiet --core="$2" 2>&1 | head -2
;;
long)
dump=$(echo -e "where\nq" | \
gdb --quiet --core="$2" 2>&1)
echo "$dump" | head -2 | sed -ne '2,2s/\.$//p'
ls -l "$2" | \
awk '{ print "on", $6, $7, $8, "caused by", $3 }'
echo
echo "backtrace:"
echo "$dump" | sed -ne '/^(gdb) /s/^(gdb) //p'
;;
esac
}
#
# start of main
#
myname=$(basename "$0") # name of shell-script
mode=standard # normal mode of operation
case "$1" in
-h | --help)
disp_help
exit 1
;;
-v | --version)
echo "version 0.1.0"
exit 0
;;
-b | --brief)
mode=brief
shift
;;
-l | --long)
mode=long
shift
;;
-* | --*)
echo "$myname: unknown option $1"
exit 2
;;
esac
if [ -z "$1" ]; then
# no argument -> look at core in the current directory
get_name "$mode" core
else
# process all arguments
for c; do
# echo file we are processing
if [ "$mode" != "brief" ]; then
echo "$c: "
fi
get_name "$mode" "$c"
done
fi
exit 0
</PRE>
<P> <hr> <P>
<!--================================================================-->
<a name="mark"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Perl Script 2C Tip
</H3><P>
Date: Mon, 16 Mar 1998 15:46:25 +0000<BR>
From: Mark Hood, <A HREF="mailto:mark.hood@deep-thought.ericsson.se">
mark.hood@deep-thought.ericsson.se</A>
<P>
After seeing the "Keeping Track of Tips" suggestion in your October
issue, I thought it might be worth contributing this perl script which I
use in a similar way.
I have a user called 'info' and he has a .forward file consisting of the
following line:
<PRE>
"| /home/info/mail2web"
</PRE>
In the user's public_html folder, I created a file called index.html:
<PRE>
&lt;HTML&gt;&lt;HEAD&gt;&lt;TITLE&gt;Information Archive&lt;/TITLE&gt;&lt;/HEAD&gt;
&lt;BODY&gt;
&lt;TABLE&gt;
&lt;TR&gt;&lt;TH&gt;Subject&lt;/TH&gt;&lt;TH&gt;Date&lt;/TH&gt;&lt;TH&gt;From&lt;/TH&gt;&lt;/TR&gt;
&lt;!-- Add after here --&gt;
&lt;/TABLE&gt;
&lt;/BODY&gt;
&lt;/HTML&gt;
</PRE>
This allows me to simply mail directly to this user, and the tip is
instantly stored on the web page - no need for cron jobs or external C
programs to split the mail up.
<P>
This file is provided for free use, feel free to distribute or alter it
in any way.
Note that there is no warranty - it works for me, but that's all I can
say. In particular, I can't promise there are no security holes in it
(it never calls 'exec', so it's unlikely a cracker can subvert it on
your machine - and it's certainly no more dangerous than a shell script
run by cron).
<P>
Enjoy! Mark Hood
<PRE>
----- Cut here and save as mail2web -----
#!/usr/local/bin/perl
#
# mail2web (C) 1998 Mark A. Hood (mark.hood@usa.net)
#
# Takes a file (piped through it, eg. from a .forward file)
# And bungs it in a Web page.
# We have two html files:
# $index is the index file
# $stem is the base name of the information files - the date & time
# are appended to make it unique.
#
# The index file must exist and look like this (without the leading #
signs)
# The important bit is the <!-- Add after here --> comment - this script
# uses that to know where to put the new data...
#
# &lt;HTML&gt;&lt;HEAD&gt;&lt;TITLE&gt;Information Archive&lt;/TITLE&gt;&lt;/HEAD&gt;
# &lt;BODY&gt;
# &lt;TABLE&gt;
# &lt;TR&gt;&lt;TH&gt;Subject&lt;/TH&gt;&lt;TH&gt;Date&lt;/TH&gt;&lt;TH&gt;From&lt;/TH&gt;&lt;/TR&gt;
# &lt;!-- Add after here --&gt;
# &lt;/TABLE&gt;
# &lt;/BODY&gt;
# &lt;/HTML&gt;
# Variables - change these to match your system
$index = "/home/info/public_html/index.html";
$stem = "/home/info/public_html/";
# Nothing below this line should need changing
# Define the time and date
($sec,$min,$hour,$mday,$mon,$syear,$wday,$yday,$isdst) = localtime;
$year = 1900 + $syear;
# Add the time and date to the end of the filestem
$stem = sprintf ("%s%02d%02d%02d%02d%02d%02d.html",
$stem, $year, $mon, $mday, $hour, $min, $sec);
# Open the new file
open ( OUTFILE, "&gt;$stem") ;
# Write the HTML header
print OUTFILE "&lt;HTML&gt;&lt;HEAD&gt;&lt;TITLE&gt;\n";
$printing = 0;
$from = "nobody";
$date = "never";
$title = "Untitled";
while ($line = &lt;&gt;) {
if ($line =~ s/^From: (.*)$/$1/g) { # Sender
$from = $line;
} elsif ($line =~ s/^Date: (.*)$/$1/g) { # Date
$date = $line;
} elsif ($line =~ s/^Subject: (.*)$/$1/g) { # Subject
$title = $line;
print OUTFILE $title;
print OUTFILE "&lt;/TITLE&gt;&lt;BODY&gt;&lt;PRE&gt;";
} elsif ($line =~ /^$/ && $printing == 0) { # End of headers
$printing = 1; # Show the info.
print OUTFILE "From: " . $from;
print OUTFILE "Date: " . $date;
print OUTFILE "Subject: " . $title . "\n";
}
$line =~ s/\&lt;/\&lt\;/g; # Mask out
specials
$line =~ s/\&gt;/\&gt\;/g;
if ($printing) {
print OUTFILE $line;
}
}
print OUTFILE "&lt;/PRE&gt;&lt;/BODY&gt;&lt;/HTML&gt;"; # Finish the
HTML
close OUTFILE; # Close the file
$newfile = sprintf("%s.new", $index); # Backups
$oldfile = sprintf("%s.old", $index);
open ( INFILE, "$index");
while ($line = &lt;INFILE&gt;) {
if ($line =~ /^\&lt;\!-- Add after here --\&gt;/ ) { # Our marker
print OUTFILE "&lt;TR&gt;&lt;TD&gt;";
print OUTFILE "&lt;A HREF=\"" . $stem . "\"&gt;";
print OUTFILE $title . "&lt;/A&gt;&lt;/TD&gt;";
print OUTFILE "&lt;TD&gt;" . $date . "&lt;/TD&gt;";
print OUTFILE "&lt;TD&gt;" . $from . "&lt;/TD&gt;&lt;/TR&gt;\n";
}
print OUTFILE $line;
}
rename ($index, $oldfile); # Backup the
current
rename ($newfile, $index); # Move the new
one
----- Cut here ----- Cut here ----- Cut here ----- Cut here -----
</PRE>
<P> <hr> <P>
<!--================================================================-->
<a name="john2"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
rxvt 0.02$ tip
</H3><P>
Date: Sun, 15 Mar 1998 17:21:26 -0500 (EST)<BR>
From: John Eikenberry [MSAI], <A HREF="mailto:jae@ai.uga.edu">
jae@ai.uga.edu</A>
<P>
Recently I hacked together a little shell script for some friends of mine
that I thought others might find of interest. It allows you to run rxvt
with a random pixmap put in the background. The random pixmap is taken
from a directory, thus no hard coding of pixmap names in the shell script.
<P>
Well, here it is... oh, this is using bash btw...
<PRE>
----start----
#!/bin/sh
run_rxvt ()
{
shift $((RANDOM%$#))
exec rxvt -pixmap ~/.pixmaps/$1
}
run_rxvt `ls ~/.pixmaps/`
</PRE>
<P> <hr> <P>
<!--================================================================-->
<a name="john3"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Tiny patch to ifconfig
</H3><P>
Date: Fri, 06 Feb 1998 23:12:02 -0600 <BR>
From: John Corey, <A HREF="mailto:kunglao@prairienet.org">
kunglao@prairienet.org</A>
<P>
I've often wondered just how much data I've transmitted through my
network. After a little research, I found that the ifconfig program
just simply does not display this bit of information in it's results.
So, I've fixed that problem.
<P>
To install, first get the sources from your favorite sunsite mirror.
The file to look for is net-tools-1.432.tar.gz. I found it at
ftp://ftp.cc.gatech.edu/pub/linux/distributions/slackware/source/n/tcpip/net-tools-1.432.tar.gz
<P>
Unpack those sources, apply the patch with patch < ifconfig.diff, and
compile. I only modify the ifconfig program, so just simply backup your
existing binary, then install the newly compiled one (assuming you
already have this version of net-tools installed). Here is an example
of the new output:
<PRE>
eth0 Link encap:Ethernet HWaddr 00:40:F6:A4:8E:73
inet addr:192.168.1.1 Bcast:192.168.1.255 Mask:255.255.255.0
UP BROADCAST RUNNING MULTICAST MTU:1500 Metric:1
RX packets:99773 errors:0 dropped:0 overruns:0 frame:0
TX packets:91834 errors:0 dropped:0 overruns:0 carrier:0
coll:6
RX bytes: 20752805 (19.7 Mb) TX bytes: 27982763 (26.6 Mb)
Interrupt:9 Base address:0x280
</PRE>
<PRE>
Content-Type: text/plain; charset=us-ascii; name="ifconfig.diff"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline; filename="ifconfig.diff"
diff -c -r net-tools/ifconfig.c net-tools-patched/ifconfig.c
*** net-tools/ifconfig.c Tue Sep 23 15:05:24 1997
--- net-tools-patched/ifconfig.c Fri Feb 6 15:54:51 1998
***************
*** 190,195 ****
--- 190,196 ----
static void
ife_print(struct interface *ptr)
{
+ unsigned long rx, tx, short_rx, short_tx; char Rext[5], Text[5];
struct aftype *ap;
struct hwtype *hw;
int hf;
***************
*** 352,357 ****
--- 353,372 ----
ptr->stats.tx_packets, ptr->stats.tx_errors,
ptr->stats.tx_dropped, dispname, ptr->stats.tx_fifo_errors,
ptr->stats.tx_carrier_errors, ptr->stats.collisions);
+
+ /* MyMod */
+ rx = ptr->stats.rx_bytes; tx = ptr->stats.tx_bytes;
+ strcpy(Rext, ""); short_rx = rx * 10; short_tx = tx * 10;
+ if (rx > 1048576) { short_rx /= 1048576; strcpy(Rext, "Mb"); }
+ else if (rx > 1024) { short_rx /= 1024; strcpy(Rext, "Kb"); }
+ if (tx > 1048576) { short_tx /= 1048576; strcpy(Text, "Mb"); }
+ else if (tx > 1024) { short_tx /= 1024; strcpy(Text, "Kb"); }
+
+ printf(" ");
+ printf(NLS_CATGETS(catfd, ifconfigSet, ifconfig_tx,
+ "RX bytes: %lu (%lu.%lu %s) TX bytes: %lu (%lu.%lu %s)\n"),
+ rx, short_rx / 10, short_rx % 10, Rext,
+ tx, short_tx / 10, short_tx % 10, Text);
if (hf<255 && (ptr->map.irq || ptr->map.mem_start || ptr->map.dma ||
ptr->map.base_addr)) {
</PRE>
<P> <hr> <P>
<!--================================================================-->
<a name="bill"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Re: Wanting HELP!
</H3><P>
Date: Wed, 04 Mar 98 13:35:24 -0500<BR>
From: Bill R. Williams, <A HREF="mailto:brw@BRW.ETSU.Edu">
brw@BRW.ETSU.Edu</A>
Status: RO
<P>
For anyone interested... IT'S FIXED! (*applause, cheering, etc.*)
On Fri, 27 Feb 98 14:16:13 -0500, I (Bill R. Williams) wrote:
<PRE>
...[snip]...<BR>
In the process of getting a System installed I upgraded from the
original CD-ROM install of (Intel) RedHat 4.2 to the new RedHat 5.0
CD-ROM. One of the significant items on this system is the mars-nwe
Netware emulator.
Under the RedHat 4.2 with mars-nwe 0.98pl8-1 the mars package ran fine,
but logged copious errors about there being "too many connections --
increase the number in config.h". But it ran, and I *liked* the way it
happily did Netware duties! (Especially the printer part.)
The *new* RedHat 5.0 with mars-nwe 0.99pl2-1 offered some very desirable
abilities, not the least of which is the move of some items (such as
number of connections) to the run-time config file (/etc/nwserv.conf
under RedHat, probably nw.ini on other distributions.) Now the bad
news...<BR>
...[snip]...<BR>
This new package spawns out nwconn processes with an empty parenthesis
as the last token instead of the USERID ('nwconn ... ()') until all
connection slots are eaten, and then, of course, will not recognize any
new attempts. Any users already logged into the nwserv(ice) are Ok.<BR>
...[snip]...<BR>
I have tried every combination of parameter twiddling in the run-time
config file that can think of, but to no avail.<BR>
...[snip]...<BR>
Anyone who has solved this problem, please share the secret.
</PRE>
BTW: I had regularly pulled in updates to everything from RedHat
errata. I was getting a bit gun shy about updating, because that's how
I got into the mess. :-) I had previously tried the "..pl2-3.rpm" when
it first appeared, but it died immediatly on startup so I went back to
the "..pl2-1.rpm" build which, at least, would run in spite of all the
problems I was having with it.
<P>
The breakthrough was inspired by a note I got when
On Mon, 02 Mar 1998 12:24:37 +0100, Trond Eivind Glomsrd wrote:
"Last: You have installed all items from the errata? The glibc updates
fixes a lot of bugs, at least."
<P>
So I made one more trip to the RH errata repository, and got the
absolute latest updates. There did happen to be a newer update of that
glibc which Tron had mentioned.
<P>
I applied the glibc updates and installed the mars-nwe 0.99pl2-3, and
this all seems to have fixed everything. Mars runs, and all the ugly
hangups and problems appear to be gone! It's a thing of beauty.
<P>
For those keeping score, here are the package levels which are
significant to running the mars-nwe on my RH 5.0 System:
<PRE>
kernel-2.0.32-2
mars-nwe-0.99pl2-3
glibc-2.0.6-9
</PRE>
It appears that the mixture of levels I had prior to this set just
did not synch up, and I suspect the the fix must have been in the new
glibc as Tron suggested it might be.
<P>
What a relief!
<P>
Bill R. Williams
<P> <hr> <P>
<!--================================================================-->
<a name="kragen"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Re: Help Wanted (usershell on console without logging in)
</H3><P>
Date: Mon, 23 Mar 1998 15:26:17 -0500 (EST)<BR>
From: Kragen, <A HREF="mailto:kragen@pobox.com">kragen@pobox.com</A>
<P>
Last month, there was a request by Todd Blake for some help:
<blockquote>
I like most people am the only person to use my linux system at home.
What I'd like to do is when my system is done booting to have me
automatically login as my main user account(not as root though) on one
virtual console(the first) and leave all other consoles and virtual
consoles alone,</blockquote>
<P>
I thought this was a good idea, so I tried to do it. Eventually, I
succeeded. The resulting software is at
http://www.pobox.com/~kragen/sw/usershell.html. Mr. Blake
reports that it is a good job.
<P>
Anyone else is welcome to it. I'll even help you if you have trouble
with it :)
<P>
Kragen
<P> <hr> <P>
<!--================================================================-->
<a name="vivek"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
2 cent tip followup -- X
</H3><P>
Date: Tue, 24 Mar 1998 14:26:43 -0500<BR>
From: Vivek Khera, <A HREF="mailto:vivek@khera.org">vivek@khera.org</A>
<P>
In the March issue, you have a tip on using X programs when you've run
su to root. By far the easiest method is to simply
<PRE>
setenv XAUTHORITY ~khera/.Xauthority
</PRE>
for your own user name, of course... No need to run any other programs
or cut and paste anything.
<P>
I have my machines configured so that when someone becomes root, if the
file ~/.rootrc exists in their home directory, it is sourced as part of
the root's .cshrc file. In there, I put the above setenv command. I've
never had to think about it again (in nearly 5 years).
<P>
Hope this helps someone.
<P>
Vivek Khera, Ph.D.
<P> <hr> <P>
<!--================================================================-->
<a name="remco"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
locate patch
</H3><P>
Date: 24 Mar 1998 11:57:20 -0000<BR>
From: Remco Wouts, <A HREF="mailto:remco@xray.bmc.uu.se">
remco@xray.bmc.uu.se</A>
<P>
In the Linux Gazette number 26 (march) there was mention of a patch
for locate. The idea of the patch was to make it impossible to find
out the names of files in directories that you do not have access to.
<P>
Unfortunately this patch does not solve the problem at all. So I would
advise people not to use this patch, they could be lured into a false
sense of privacy. What is the problem and what is wrong with the
patch?
<P>
Locate allows you to find a file quickly. It does this by consulting a
database of filenames. Of course this way of finding a file is much
quicker then hunting for it in the file system. However, somebody has
to make the database. This is done with the program updatdb, usually
from a crontab every day or week. Updatdb can find all files that the
user id, it is running as, has access to. So if updatedb is run with
an id that has more access rights then the user who invokes the locate
command, this user can find out the names of files that he/she
otherwise could not find. The author of the locate patch solved the
problem simply by changing the locate command. Just before sending the
name of a file, it checks whether it exists and if so whether the
invoking user has read access. However you don't need to use the
locate command at all to read the file database. To make sure every
user, who invokes locate, can read it it is stored world readable. The
patch does not help at all to solve the privacy problem.
<P>
For the moment, if you are concerned about these privacy issues, you
should not run 'updatedb' at all, and remove the existing database.
Since locate & Co. are very handy utilities it is probably best to
leave things as they are and make sure updatedb is run by user nobody
from a crontab.
<P>
The next easiest solution would be to make the database created by
updatedb readable by root only, and change locate to a setuid program
which consults the database as root and checks for permissions. I
will leave that as a challenge to the author of the patch.
<P>
Happy Linuxing.<BR>
-- Remco Wouts
<P> <hr> <P>
<!--================================================================-->
<a name="padraig"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
locate subdirectories
</H3><P>
Date: Thu, 26 Mar 1998 17:02:22 +0000 (GMT)<BR>
From: <A HREF="mailto:Padraig.Finnerty@acm.org">
Padraig.Finnerty@acm.org</A>
<P>
in a large directory of files it is sometimes hard to locate the
subdirectories. to do this you can tag the directories with a '/'
(using ls -F) and then grep these out...
<PRE>
ls -F |grep /$
</PRE>
or even better..
<PRE>
alias sub="ls -F |grep /$"
</PRE>
Padraig
<P> <hr> <P>
<!--================================================================-->
<center>Published in <I>Linux Gazette</I> Issue 27, April 1998</center>
<P> <hr> <P>
<!--================================================================-->
<A HREF="./index.html"><IMG SRC="../gx/indexnew.gif" ALT="[ TABLE OF
CONTENTS ]"></A> <A HREF="../index.html"><IMG SRC="../gx/homenew.gif"
ALT="[ FRONT PAGE ]"></A> <A HREF="./lg_mail27.html"><IMG SRC="../gx/back2.gif" ALT=" Back "></A>
<A HREF="./lg_bytes27.html"><IMG SRC="../gx/fwd.gif" ALT=" Next "></A>
<P> <hr> <P>
<h5>This page maintained by the Editor of <I>Linux Gazette</I>,
<A HREF="mailto: gazette@ssc.com">gazette@ssc.com</A><BR>
Copyright &copy; 1998 Specialized Systems Consultants, Inc. </H5>
<P>
<H4>"Linux Gazette...<I>making Linux just a little more fun!</I>"</H4>
<HR>
<center>
<table cellpadding=7><tr><td>
<IMG SRC="../gx/bytes.gif" border=1 ALT="News Bytes">
</td><td>
<H3>Contents:</H3>
<ul>
<li><a HREF="./lg_bytes27.html#general">News in General</a>
<li><a HREF="./lg_bytes27.html#software">Software Announcements</a>
</ul>
</td></tr></table>
</center>
<a name="general"></a>
<p><hr><p>
<!-- =================================================================== -->
<center><H3> News in General </H3></center>
<P> <hr> <P>
<!-- =================================================================== -->
<center><IMG ALT=" " SRC="./gx/cover49.gif"></center>
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
May <I>Linux Journal</I>
</H3>
<P>
The May issue of <A HREF="http://www.linuxjournal.com/"><I>Linux
Journal</I></A> will be hitting the newsstands April 10.
The focus of this issue is Cross Platform Development with
articles on building reusable Java Widgets, debugging your Perl programs,
Modula-3, doubly-linked lists, the Python DB-API and much more. Check out the
<A HREF="http://www.linuxjournal.com/issue49/index.html">Table of Contents</A>.
To subscribe to <I>Linux Journal</I>, click <A
HREF="http://www.linuxjournal.com/ljsubsorder.html">here</A>.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Linus Torvalds Receives VA Research Excellence Award
</H3>
<P>
February 26, 1998<BR>
VA Research granted its Excellence in Open Source Software Award to
Linus Torvalds, father of the Linux operating system and one of the most
important leaders in information technology. Linus received a
VArStation YMP, worth $4500, at
The Silicon Valley Linux Users Group meeting in March. (See <A
HREF="./dibona.html">article</A> in this issue by Chris Dibona.)
<P>
The VA Research Excellence in Open Source Software Award honors
exceptional individuals within the free software community. Torvalds led
this community to create Linux, a freely distributable multi-user,
multi-tasking Unix-like operating system. Linux is now used in a range of
applications from mission critical servers to desktop workstations.
<P>
VA Research is the oldest and largest Linux systems company. Founded in
1993 by electrical engineering doctoral students at Stanford University,
VA Research pioneered high performance workstations and servers based on
Linux. In 1997, VA Research became an affiliate of Umax.
<P>
For More Information:<BR>
VA Research, www.varesearch.com <BR>
Samuel Ockman, ockman@varesearch.com.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
New Linux and Open Source Business Usage Advocacy page
</H3>
<P>
Date: Thu, 12 Mar 1998 21:06:35 +1100 (EST)<BR>
There is a new advocacy page for Linux (and other
open source, free software). This site is primarily focused on solid
business reasons as to why companies should use Linux. The opening
blurb states:
<P>
...
We (and a growing number of other firms) are heavy users of software such
as Linux, GNU and FreeBSD which can be classified as 'freely redistributable' or 'co-operatively developed',
but feel that there is considerable lack of knowledge of these systems and applications in the
general business community. We (and some of the companies listed below) are therefore
building this web presence to help provide information, documentation, showcase projects, links to
related sites and other useful resources to to help redress this. This will include freely
redistributable systems software, and free and commercial applications which run on these systems which may
be of interest to helping you run your business.
...
<P>
<A
HREF="http://www.cyber.com.au/misc/frsbiz/">http://www.cyber.com.au/misc/frsbiz/</A>
<P>
For More Information:<BR>
Con Zymaris, Cybersource Pty. Ltd.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
FREENIX at USENIX Annual Conference
</H3>
<P>
Date: Mon, 16 Mar 1998 08:54:19 -0800<BR>
Here's more than you ever wanted to know:
<P>
<P>
Share ideas, and actual code, with developers and avid users of freely
redistributable software--Linux, FreeBSD, NetBSD, OpenBSD, and more--at the
23RD ANNUAL USENIX TECHNICAL CONFERENCE,
includes FREENIX, the Freely Redistributable Software Track,
June 15-19, 1998 in
New Orleans, Louisiana.
Sponsored by USENIX, the Advanced Computing Systems Association
<P>
FREENIX is co-sponsored by The FreeBSD Project, Linux International, The
NetBSD Foundation, Inc., and The OpenBSD Project
<P>
Full program and on-line registration:<BR>
<A
HREF="http://www.usenix.org/events/no98/">http://www.usenix.org/events/no98/</A>
<BR>
Email: <A HREF="mailto:conference@usenix.org">conference@usenix.org</A>
<P>
FREENIX, a Special Track within the conference, showcases the latest
developments and interesting applications in freely redistributable
software. FREENIX offers 28 talks, plus evening BoF sessions.
<P>
USENIX is the Advanced Computing Systems Association. Its
members are the computer technologists responsible for many of
the innovations in computing we enjoy today.
<P>
For More Information:<BR>
Cynthia Deno, USENIX ASSOCIATION,
<A HREF="mailto:cynthia@usenix.org">cynthia@usenix.org</A> <BR>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Samba: Integrating UNIX and Windows
</H3>
<P>
Date: Fri, 6 Mar 1998 08:36:32 GMT<BR>
Samba is the tool of choice for providing Windows file sharing and
printer services from UNIX and UNIX-like systems. Freely available
under the GNU Public License, Samba allows UNIX machines to be
seamlessly integrated into a Windows network without installing any
additional software on the Windows machines. Used in tandem with Linux
or FreeBSD, Samba provides a low-cost alternative to the Windows NT
Server.
<P>
This book, a combination of technical tutorial, reference guide, and
how-to manual, contains the depth of knowledge experienced network
administrators demand without skipping the information beginners need to
get fast results. UNIX administrators new to Windows networking will find
the information they need to become Windows networking experts. Those new
to UNIX will find the details they need to install and configure Samba
correctly and securely.
<P>
The book also contains a CD-ROM containing version 1.9.18 of the Samba
server, a library of useful tools and scripts, the Samba mailing list
archives, and all examples discussed in the book.
<ul>
<li>Title: Samba: Integrating UNIX and Windows
<li>Author: John D. Blair, Samba Team
<li>Publisher: Specialized Systems Consultants Inc. (SSC)
<li>Pub Date: 2/98
<li>Retail Price: $29.95
<li>ISBN: 1-57831-006-7
<li>URL: www.ssc.com/ssc/samba/
<li>Contact: <A HREF="mailto:samba@ssc.com">Clarica Grove</A>
</ul>
<P>
Currently available at fatbrain.com (Book shops + Online).
www.clbooks.com * 1-800-789-8590 * FAX 1-408-752-9919
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Netscape turns to Debian for Licensing Guidance!
</H3>
<P>
Date: Fri, 6 Mar 1998 09:23:38 GMT<BR>
When Netscape decided to make their client software free, they
used the Debian Free Software Guidelines for a guide on how to
write their license. You can find the draft Netscape license at
<A HREF="http://www.mozilla.org/NPL/">http://www.mozilla.org/NPL/</A>.
This is a historic day for us, since it
means that "Mozilla" (Netscape Communicator) will eventually be in the
"main" part of Debian and all Linux systems, instead of the "non-free" section
as it is now.
<P>
A link to a Netscape press release (containing a quote from Bruce Perens)
can be found at <A
HREF="http://www.netscape.com/newsref/pr/newsrelease579.html">
http://www.netscape.com/newsref/pr/newsrelease579.html</A>.
The Debian Social Contract and licensing guidelines are at
<A
HREF="http://www.debian.org/social_contract.html">http://www.debian.org/social_contract.html</A>.
A web page on the
Open Source promotional program for free software can be found at
<A HREF="http://www.opensource.org/">http://www.opensource.org/</A>.
<P>
There is work yet to be done - a few license bug-lets will be resolved
within the next few days, and once the source code is released there are
some parts that Netscape does not own that will most likely have to be
replaced with free software.
<P>
For More Information:<BR>
Bruce Perens, <A
HREF="mailto:bruce@debian.novare.net">bruce@debian.novare.net</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Linux Web Watcher News
</H3>
<P>
Date: Tue, 10 Mar 1998 13:18:11 GMT<BR>
<P>
Linux Web Watcher, <A
HREF="http://webwatcher.org/">http://webwatcher.org/</A>
<P>
The "Linux Web Watcher" now has its own domain, thanks to VA Research. LWW
isn't an ordinary
links page. It actually keeps track of when the pages were last updated,
so you don't have to waste hours checking to see if your favorite web
pages have been updated since your last visit to them.
<P>
The non-tables page of the Linux Web Watcher have been greatly
enhanced to make things easier
to read for Lynx users.
<P>
For More Information:<BR>
Robert E. Blue, <A HREF="mailto:reblue@emry.net">reblue@emry.net</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Linux questionnaire
</H3>
<P>
Date: Tue, 10 Mar 1998 13:19:49 GMT<BR>
Aachen Linux User Group (ALUG) proudly presents the
<A HREF="http://aachen.heimat.de/alug/fragebogen2">Linux Questionnaire</A>.
<P>
The questionnaire consists of 20 questions which
cover software, hardware, documentation and installation issues. The
questions are a mixture of multiple choice and text areas. The results
are updated hourly and can be seen at:<BR>
<A
HREF="http://aachen.heimat.de/alug/fragebogen2/fragebogen_results2.html">
http://aachen.heimat.de/alug/fragebogen2/fragebogen_results2.html</A>
<P>
The objective of the questionnaire is to provide a somewhat
standardized way to report your experience with Linux and the results
should give (in particular, to the newcomer) a coarse-grained view on
Linux and its users.
<P>
For More Information:<BR>
Aachener Linux User Group (Aachen/Germany),
<A HREF="http://aachen.heimat.de/alug">http://aachen.heimat.de/alug</A>
<BR>
Michael Eilers, <A HREF="mailto:eilers@rmi.de">eilers@rmi.de</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Perl Conference 2.0 - Call for Participation
</H3>
<P>
Date: Tue, 10 Mar 1998 14:43:42 GMT<BR>
The second annual <A HREF="http://conference.perl.com/">O'Reilly Perl
Conference</A> will be held August
17-20, 1998 at the Fairmont Hotel in San Jose, California. The
conference will feature two days of tutorials followed by a two
day conference. The conference will include sessions for
submitted papers on practical and experimental uses of Perl;
invited presentations; daily Q and A sessions with leading
Perl developers and trainers; a by-invitation Developers
Workshop; and nightly user-organized Birds-of-a-Feather sessions
for special interest groups.
<P>
In the practical spirit of Perl, we seek papers that describe
how you are using Perl right now for work or play, and how your
experience and your code can help others. This is not a
traditional solicitation for academic papers. While we look
forward to papers on new and useful extensions, applications,
and tools, we are most interested in receiving papers that show
Perl hard at work, saving time, money, and headaches for you and
your organization. We welcome submissions that work under both
Unix and non-Unix systems, such as Win32.
<P>
For More Information:<BR>
The Perl Institute, Chip Salzenberg<BR>
3665 E. Bay Drive, Suite 204-A <BR>
Largo, FL 33771-1990
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
UK Linux Conference
</H3>
<P>
Date: Mon, 23 Mar 1998 09:18:30 GMT<BR>
These are very preliminary details:<BR>
<P>
Venue:
UMIST Conference Centre, Manchester.
<P>
Date:
Saturday 27th June
<P>
Time:
A Jam-packed day from 10am (sharp) to around 5:30
<P>
Programme (provisional):
<ul>
<li>Richard Moore (University of Manchester): KDE Internals
<li>Stephen Tweedie (DEC): Journaling File Systems
<li>Gareth Bult (Frontier Technology): Linux Means Business
<li>Ian Jackson (Debian): Title TBDC
<li>Jeremy Chatfield (Xi Graphics): X
</ul>
<P>
For More Information:<BR>
UKUUG, <A HREF="http://www.ukuug.org/">http://www.ukuug.org/</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
French Translation of <I>LG</I> Issue 25
</H3>
<P>
A French translation of some parts of Issue 25 of the <I>Linux Gazette</I> is
available at the following URL's :<BR>
<a
href="http://www.linux-kheops.com/pub/lgazette/&gt">http://www.linux-kheops.com/pub/lgazette/</a>;<BR>
<B>and</B>
<a
href="http://www.linux-france.com/article/lgazette/&gt">http://www.linux-france.com/article/lgazette/</a>;<BR>
<P>
For more information: <BR>
Eric Jacoboni : jaco@mail.dotcom.fr
<a name="software"></a>
<P> <hr> <P>
<!-- =================================================================== -->
<center><H3> Software Announcements </H3></center>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Help ToolKit for Motif V0.9: Binary beta release now available
</H3>
<P>
Date: Sun, 1 Mar 1998 23:58:55 -0500<BR>
Columbia, MD -- The Help ToolKit for Motif V0.9 has been released and is
now available on the web.
The Help ToolKit for Motif allows developers to easily add and modify
various types of on-line context-sensitive help to Motif applications.
Using a small set of functions to install the library, every widget and
gadget in a Motif application seemingly inherits new resources allowing
help to be configured and changed via X resource files.
<P>
The ToolKit supports three core help types: Tips, Cues, and Hints. All of
these help types can be assigned to any widget and any Motif-based gadget.
<P>
The Help ToolKit distribution can be downloaded from
<A HREF="http://www.softwarecomp.com">http:www.softwarecomp.com</A>.
The complete Programmer's Manual can also be downloaded in PDF format from
the same site.
<P>
Although the Linux version of this product is freely available for
non-commercial purposes, it is copyrighted and is not in the public domain.
There is a license associated with the distribution; please read it if you
have an interest in the product.
<P>
For more information:<BR>
Robert S. Werner, <A HREF="mailto:rob.werner@softwarecomp.com">
rob.werner@softwarecomp.com </A> <BR>
<A HREF="mailto:info@softwarecomp.com">info@softwarecomp.com</A>,
<A HREF="http://www.softwarecomp.com/">http://www.softwarecomp.com/</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
RED HAT SOFTWARE NOW SHIPPING MOTIF 2.1
</H3>
<P>
Date: Tue, 03 Mar 1998 16:16:34 -0500<BR>
Research Triangle Park, NC--March 2, 1998--Red Hat Software, Inc.,
publisher of Red Hat Linux 5.0, the Operating System that was named
InfoWorld Magazine's Product of the Year, has announced the
availability of Red Hat Motif 2.1 for the Intel Computer. Red Hat
Motif 2.1 for the Intel computer is the full OSF/Motif development
system. As with the 2.0.1 version of Red Hat Motif, Red Hat Motif 2.1
can turn your Intel computer running Linux into a complete Motif
development workstation.
<P>
For more information:<BR>
Red Hat Software, Inc., <A
HREF="http://www.redhat.com">"http://www.redhat.com/</A>, <A
HREF="mailto:melissa@redhat.com">melissa@redhat.com</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
PostShop, ScanShop and OCR Shop
</H3>
<P>
Date: Fri, 6 Mar 1998 11:38:10 -0800 (PST)<BR>
Vividata, Inc. announced the release of Linux versions of its PostShop,
ScanShop and OCR Shop software products PostShop transforms inkjet and laser
printers to PostScript-enabled ones and makes PostScript printers up to 100
times faster. ScanShop scans, prints, compresses, stores, retrieves and
displays pictures and documents in full color, grayscale, and bi-level
(black & white), and OCR Shop converts paper documents and images into
editable text.
<P>
For more information:<BR>
Vividata, Inc., <A HREF="mailto:info@vividata.com">info@vividata.com</A>,
<A HREF="http://www.vividata.com/">http://www.vividata.com/</A>.
Cobalt Qube Ships
<P>
MOUNTAIN VIEW, Calif., March 17, 1998 - Cobalt Microserver Inc. today
announced that its Cobalt Qube(tm) microserver products, which were
introduced last month at the DEMO 98 conference, have begun shipping to
customers. Cobalt develops and markets simple, low-cost Internet and
Intranet servers.
<P>
The Cobalt Qube microservers are aimed at work groups and branch offices,
Internet service providers, Web developers and educational organizations.
They are simple, versatile, scalable, and offer excellent performance for
work groups at a fraction of the cost of traditional UNIX(R) and Windows(R)
NT servers.
<P>
For more information: <BR>
Nancy Teater, Hamilton Communications, <A HREF="mailto:nrt@hamilton.com">
nrt@hamilton.com</A>,
<A HREF="http://web.hamilton.com/">http://web.hamilton.com/</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
LinkScan 4.0
</H3>
<P>
Date: Fri, 13 Mar 1998 13:24:29 -8<BR>
San Jose, CA, March 10, 1998 - Electronic Software Publishing Corp.
(Elsop) introduces a number of new features to enhance the central
management of multiple Intranet/Internet web sites in organizations where
many different individuals may be responsible for the content. These
developments build upon earlier releases which laid down the foundations
for these exciting new features. LinkScan enables users to split-up very
large sites into smaller sub-sites, to produce different reports for
different departments and to configure LinkScan to handle multiple
domains hosted on a single server. LinkScan/Dispatch adds a new higher
level of capability to those features.
<P>
LinkScan/Dispatch is included with LinkScan Version 4.0. It is designed
for operators of large web sites where the responsibility for maintenance
and updates is distributed among many individuals.
<P>
LinkScan 4.0 is priced at $750 per server. Volume discounts are
available in single order quantities of five copies or more. Orders may
be placed online via a secure server.
<P>
For more information:<BR>
Kenneth R. Churilla,
<A HREF="mailto:ken@elsop.com">ken@elsop.com</A><BR>
Electronic Software Publishing Corporation,
<A HREF="http://www.elsop.com/">http://www.elsop.com/</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
WANPIPE FT1
</H3>
<P>
Date: Thu, 12 Mar 1998 14:25:12 +0000<BR>
Sangoma Technologies Inc.
(OFFER VALID UNTIL APRIL 15TH OR WHILE SUPPLIES LAST)
is making available our WANPIPE kit
that includes the T1 and Fractional T1 DSU/CSU for an END USER price
of $799.00! This represents a reduction of 30% from our already low
standard price of $1139.00.
<P>
WANPIPE provides all you need to turn your NT, Linux, or
NetWare server or Windows workstation into a powerful T1 or
Fractional T1 router for your LAN. Just plug your server into the
wall.
<P>
For more information:<BR>
David Mandelstam, <A HREF="mailto:dm@sangoma.com">dm@sangoma.com</A> <BR>
Sangoma Technologies Inc.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
XFree86 3.3.2 Released
</H3>
<P>
Date: Fri, 6 Mar 1998 09:59:39 GMT
XFree86 version 3.3.2 is now available. The XFree86 3.3 distribution is
available in both source and binary form. Binary distributions are
currently available for FreeBSD (2.2.2+ and 3.0-CURRENT), NetBSD (1.2
and 1.3), OpenBSD, Interactive Unix, Linux (ix86 and AXP), SVR4.0,
UnixWare, OS/2, Solaris 2.6 and LynxOS AT.
<P>
The XFree86 documentation is available on-line on our Web server. The
documentation for 3.3 can be accessed at http://WWW.XFree86.org/3.3/.
<P>
Source patches are available to upgrade X11R6.3 PL2 from the X Consortium (now
The Open Group) to XFree86 3.3.2. Binaries for many OSs are also available.
The distribution is available from:<BR>
<A
HREF="ftp://ftp.XFree86.org/pub/XFree86/">ftp://ftp.XFree86.org/pub/XFree86</A>
<P>
For more information: <BR>
The XFree86 Team, <A HREF="
mailto:robin@interlabs.com">robin@interlabs.com</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
scwm 0.6 - Scheme Configurable Window Manager
</H3>
<P>
Date: Tue, 10 Mar 1998 12:38:35 GMT<BR>
Scwm 0.6 is released.
Scwm is the Scheme Configurable Window Manager. This is a highly
dynamic and extensible window manager for the X Window System (based
originally on FVWM2, but now much enhanced) with Guile Scheme as the
configuration/extension language. Nearly all decorations can be
changed at run-time or per-window, and eventually many decoration
styles and additional features will be supported through dynamically
loaded code. A powerful protocol is provided for interacting with the
window manager while it is running.
<P>
You can download the latest scwm package from:<BR>
<A HREF="http://web.mit.edu/mstachow/www/scwm-0.6.tar.gz">
http://web.mit.edu/mstachow/www/scwm-0.6.tar.gz</A> <BR>
<A HREF="http://web.mit.edu/mstachow/www/scwm-icons-0.6.tar.gz">
http://web.mit.edu/mstachow/www/scwm-icons-0.6.tar.gz</A>
<P>
For more information: <BR>
Maciej Stachowiak, <A HREF="mailto:mstachow@mit.edu">mstachow@mit.edu</A>,
<BR>
Massachusetts Institute of Technology,
<A HREF="http://web.mit.edu/mstachow/www/scwm.html">
http://web.mit.edu/mstachow/www/scwm.html</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Yalsim, Yet Another Logic/Timing Simulator
</H3>
<P>
Date: Tue, 10 Mar 1998 12:44:50 GMT
This is the second Alpha version of a logic/timing simulator called Yalsim.
Yalsim is a hierarchical timing and logic simulator that has been in
development (on and off) for over fifteen years and the second pre-beta version
is now being sampled. Yalsim can now be obtained (with source code) by
individuals from:
<P>
<A HREF="ftp:/ftp.eecg.toronto.edu/pub/software/martin/yalsim.tar.gz">
ftp:/ftp.eecg.toronto.edu/pub/software/martin/yalsim.tar.gz</A>
<P>
The current cost for Yalsim is $1 CDN, when you have time to send it.
Sending four U.S. quarters is also acceptable. This may change in the future.
However, seriously, please do read the LICENSE file. Yalsim is not public domain
or being released under a GNU-like license, although individuals, at non-profit
institutions, will always be able to obtain at least binary versions of Yalsim
at no or minimal (overhead) cost.
<P>
For more information: <BR>
Ken Martin,
<A HREF="mailto:martin@isis.eecg.toronto.edu">martin@isis.eecg.toronto.edu</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
SQL RDBMS PostgreSQL v6.3 released for Linux
</H3>
<P>
Date: Tue, 10 Mar 1998 12:56:10 GMT<BR>
SQL RDBMS PostgreSQL v6.3 released for Linux.
PostgreSQL is a RDBMS SQL server which is the "default SQLserver"
shipped with most Linux distributions.
<P>
For more information: <BR>
<A HREF="http://www.postgresql.org/">http://www.postgresql.org/</A>,
<A HREF="mailto:gold_bag@yahoo.com">gold_bag@yahoo.com</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
nosql-0.9 - Unix RDBMS
</H3>
<P>
Date: Tue, 10 Mar 1998 12:57:56 GMT<BR>
A new release of NoSQL is available at :
<A HREF="ftp://ftp.linux.it/pub/database/nosql-0.9.tar.gz">
ftp://ftp.linux.it/pub/database/nosql-0.9.tar.gz</A>
<P>
NoSQL is a simple Relational Database Management System for Unix.
There have been several major changes from v0.8 to v0.9.
Please read file README-v0.9 distributed with the package.
<P>
For more information: <BR>
ILS - Italian Linux Society,
Carlo Strozzi, <A HREF="mailto:carlos@linux.it">carlos@linux.it</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
RITW: Very simple network monitoring tool
</H3>
<P>
Date: Tue, 10 Mar 1998 13:12:39 GMT<BR>
RITW is a small set of scripts that allow any user to monitor
network/host
status using a common WWW browser and a central monitoring site through
ICMP and HTTP.
Although it will probably run on any platform, it was only tested on
Linux.
<P>
Primary site is at <BR>
<A HREF="http://www.terravista.pt/Ancora/1883/ritw_e.html">
http://www.terravista.pt/Ancora/1883/ritw_e.html</A> <BR>
<A HREF="http://www.terravista.pt/Ancora/1883/ritw.html">
http://www.terravista.pt/Ancora/1883/ritw.html</A> (portuguese)
<P>
For more information: <BR>
Rui Pedro Bernardinoa, Parque Expo'98, Portugal,
<A HREF="mailto:rbernardino@expo98.pt">rbernardino@expo98.pt</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Socket Script v1.5
</H3>
<P>
Date: Tue, 10 Mar 1998 13:30:15 GMT
Socket Script has been made for people who wants to create
networking-oriented programs, but don't want to learn all the socket
stuff. It has multiple network commands that enable you to tell the
SScript interpreter where you want to connect, and all you have to
do is focus on the script itself, leaving the connection parts to
SScript. The best part is that most scripts will run on most Unix
workstations, and win32 platforms.
<P>
Available at:<BR>
<A HREF="http://devplanet.fastethernet.net/sscript.html">
http://devplanet.fastethernet.net/sscript.html</A>
<P>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
newsfetch-1.11 - pull news via NNTP to a mailbox
</H3>
<P>
Date: Tue, 10 Mar 1998 14:10:57 GMT<BR>
newsfetch: Most Compact and Powerful Utility to download the news from
an NNTP server and stores in the mailbox format.
New version of newsfetch (1.11) is uploaded to sunsite.unc.edu:
<P>
newsfetch-1.11.tar.gz
newsfetch-1.11-1.i386.rpm
newsfetch-1.11-1.src.rpm
<P>
available in ftp://sunsite.unc.edu/pub/Linux/Incoming/
and in proper place (/pub/Linux/system/news/reader) when they move the
files. New version is available in .tar.gz and .rpm format.
<P>
For more information: <BR>
Yusuf Motiwala, <A
HREF="mailto:ymotiwala@hss.hns.com">ymotiwala@hss.hns.com</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
nv-dc1000 digital camera image reader v0.1 beta
</H3>
<P>
Date: Tue, 10 Mar 1998 14:30:22 GMT<BR>
A small program to transfer images from the digital still camera known as
NV-DC1000 or PV-DC1000 from Panasonic. First beta version, but it works.
<P>
For more information: <BR>
Societas Datoriae Universitatis Lundensis et Instituti Technici
Lundensis<BR>
Fredrik Roubert, <A HREF="mailto:roubert@df.lth.se">roubert@df.lth.se</A>,
<A HREF="http://www.df.lth.se/~roubert/NV-DC1000.html">
http://www.df.lth.se/~roubert/NV-DC1000.html</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Cecilia2.0 - electroacoustic music software
</H3>
<P>
Date: Tue, 17 Mar 1998 08:45:31 GMT<BR>
<P>
We are happy to announce version 2 of CECILIA, the musician's software that
makes you funnier, smarter and more attractive to the opposite sex.
<P>
Cecilia was developed by composers of electroacoustic music for composers of
electroacoustic music. If you have to ask, don't bother.
Cecilia is probably the wackiest sound maker in the world at this time. In fact,
we believe nothing else even comes close.
Cecilia is for high-concept audio processing. It is not for sequencing your
rinky-dink samplers and synths.
<P>
Cecilia is freeware at present. The next version will not be. Count your blessings.
Cecilia runs on Macintoshes, Linux boxes and SGIs. It does not run on
Windows. When it does, we'll sell it and become obscenely wealthy.
<P>
Cecilia is strictly for people who have a sense of humour. We, on the other
hand, are very cranky people.
<P>
Cecilia is available for download at :<BR>
<A HREF="ftp://ftp.musique.umontreal.ca/pub/cecilia/">
ftp://ftp.musique.umontreal.ca/pub/cecilia/</A> <BR>
<P>
Cecilia's home page for manuals and info:<BR>
<A HREF="http://www.musique.umontreal.ca/CEC/">
http://www.musique.umontreal.ca/CEC/</A>
<P>
For more information: <BR>
Jean Piche, Universite de Montreal <BR>
<A HREF="http://mistral.ere.umontreal.ca/~pichej">
http://mistral.ere.umontreal.ca/~pichej</A>,
<A HREF="http://www.musique.umontreal.ca/electro/CEC/">
http://www.musique.umontreal.ca/electro/CEC/</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Free CORBA 2 ORB - omniORB 2.5.0 released.
</H3>
<P>
Date: Tue, 17 Mar 1998 09:12:28 GMT<BR>
The Olivetti and Oracle Research Laboratory has made available the second
public release of omniORB (version 2.5.0). We also refer to this version
as omniORB2.
The main change since the last public release (release 2.4.0) is the addition
of support for type Any and TypeCode. For further details of the changes, see
http://www.orl.co.uk/omniORB/omniORB_250/
<P>
omniORB2 is copyright Olivetti & Oracle Research Laboratory. It is free
software. The programs in omniORB2 are distributed under the GNU General
Public License as published by the Free Software Foundation. The libraries
in omniORB2 are distributed under the GNU Library General Public
License.
<P>
Source code and binary distributions are available from our Web pages:
<A HREF="http://www.orl.co.uk/omniORB/omniORB.html">
http://www.orl.co.uk/omniORB/omniORB.html</A>
<P>
omniORB2 is not yet a complete implementation of the CORBA core.
<P>
For more information:<BR>
Eoin Carroll, <A HREF="mailto:ewc@orl.co.uk">ewc@orl.co.uk</A> <BR>
Olivetti & Oracle Research Lab, Cambridge, UK
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Mtools 3.9 - Access MS-Dos/Win 95 disks from Unix without mounting
</H3>
<P>
Date: Tue, 17 Mar 1998 08:38:33 GMT<BR>
I would like to announce a new release of Mtools, a collection of
utilities to access MS-DOS disks from Unix without mounting them.
<P>
Mtools supports Win'95 style long file names, FAT32, OS/2 Xdf disks
and 2m disks (store up to 1992k on a high density 3 1/2 disk). Mtools
also includes mpartition, a simple partitioning programming to setup
Zip and Jaz media on non-PC machines (SunOs, Solaris and HP/UX).
<P>
Mtools can currently be found at the following places:<BR>
<A HREF="http://linux.wauug.org/pub/knaff/mtools/">
http://linux.wauug.org/pub/knaff/mtools</A> <BR>
<A HREF="http://www.poboxes.com/Alain.Knaff/mtools/">
http://www.poboxes.com/Alain.Knaff/mtools/</A>
<P>
For more information:<BR>
Alain Knaff, <A HREF="mailto:knaff@tux.org">knaff@tux.org</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
New XML.com site
</H3>
<P>
Date: Wed, 25 Mar 1998 20:08:29 -0800 (PST)
SEBASTOPOL, CA--XML, the industrial-strength mark-up language
used for Web development, is a
tool for electronic commerce and information management.
With the recent approval of the XML Specification by the World Wide Web
Consortium (W3C), interest in XML development has picked up
considerable steam.
<P>
To promote the development and commercial acceptance of XML, three
companies that have long been Web insiders--O'Reilly & Associates,
their affiliate Songline Studios, and Seybold Publications--have joined
together to create XML.com (http://www.xml.com), a new Web site that
serves as a key resource and nerve center for XML developers and users.
A preview site is now available, and the launch date for the full site
is May 1, 1998.
<P>
XML.com features a rich mix of information and services for the XML
community. The site is designed to serve both people who are already
working with XML and those HTML users who want to "graduate" to XML's
power and complexity.
<P>
For more information:<BR>
Sara Winge, <A HREF="mailto:sara@ora.com">sara@ora.com</A>
<P> <hr> <P>
<!--================================================================-->
<center>Published in <i>Linux Gazette</i> Issue 27, April 1998</center>
<P> <HR> <P>
<!-- =================================================================== -->
<A HREF="./index.html"><IMG SRC="../gx/indexnew.gif" ALT="[ TABLE OF
CONTENTS ]"></A>
<A HREF="../index.html"><IMG SRC="../gx/homenew.gif" ALT="[ FRONT
PAGE ]"></A>
<A HREF="./lg_tips27.html"><IMG SRC="../gx/back2.gif" ALT=" Back "></A>
<A HREF="./lg_answer27.html"><IMG SRC="../gx/fwd.gif" ALT=" Next "></A>
<P><HR><P>
<h5>This page written and maintained by the Editor of <I>Linux Gazette</I>,
<A HREF="mailto: gazette@ssc.com">gazette@ssc.com</A><BR>
Copyright &copy; 1998 Specialized Systems Consultants, Inc. </H5>
<P>
<H4>"Linux Gazette...<I>making Linux just a little more fun!</I>"
</H4>
<P> <hr> <P>
<!-- =============================================================== -->
<center>
<H1><A NAME="answer">
<img src="../gx/ans.gif" alt="" border=0 align=middle>
The Answer Guy
<img src="../gx/ans.gif" alt="" border=0 align=middle>
</A></H1> <BR>
<H4>By James T. Dennis,
<a href="mailto:linux-questions-only@ssc.com">linux-questions-only@ssc.com</a><BR>
Starshine Technical Services, <A HREF="http://www.starshine.org/">
http://www.starshine.org/</A> </H4>
</center>
<p><hr><p>
<H3>Contents:</H3>
<ul>
<li><a HREF="./lg_answer27.html#mccluan">Regarding Compile Errors with
Tripwire 1.2</a>
<li><a HREF="./lg_answer27.html#karsh">Applix Spreadsheet ELF Macro
Language</a>
<li><a HREF="./lg_answer27.html#geene">Answer Guy Issue 18 -- Procmail Spam
Filter</a>
<li><a HREF="./lg_answer27.html#geene2">Great Procmail Article</a>
<li><a HREF="./lg_answer27.html#sindona">Linux Cluster Configuration</a>
<li><a HREF="./lg_answer27.html#holloway">IP Masquerading/Proxy?</a>
</ul>
<p><hr><p>
<!--================================================================-->
<a name="mccluan"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Regarding Compile Errors with Tripwire 1.2
</h3>
<P> <B>
From: Tc McCluan, <A HREF="mailto:tc@4dcomm.com">tc@4dcomm.com</A>
</B> <P><B>
<img align=bottom alt=" " src="../gx/ans2.gif">
I was on http://www.starshine.org/linux/ and since I am unable to
compile Tripwire 1.2 on my system (redhat 4.2 with 2.0.33 kernel)
I am trying all avenues of help.
</B> <P><B>
I have tried the recommendation in the /contrib/README.linux but
I still get the same error message. I have tried many combinations,
but still no luck.
</B> <P><B>
Following are the list of errors I am getting, hopefully you can spot where
this compile is failing.
Thanks in advance,
</B> <P>
<img align=bottom alt=" " src="../gx/ans2.gif">
You could look for my Tripwire patch at
<P>
http://www.starshine.org/linux/
<P>
... or you could grab the RPM file from any Red Hat "contrib"
mirror like:
<P>
ftp://ftp.redhat.com/pub/contrib/i386/tripwire-1.2-1.i386.rpm
<P>
... for a precompiled binary or:
<P>
ftp://ftp.redhat.com/pub/contrib/SRPMS/tripwire-1.2-1.src.rpm
<P>
... for sources that you should be able to build cleanly.
<P>
So far I really haven't found a tripwire configuration that I really
like. I can never quite get the balance between what aspects to ignore
(permission and ownership changes on /dev/tty*, /dev/pty*, etc) and
which ones I need to watch.
<P>
So, if anyone out there as a really good tw.config file that really
minimizes the superfluous alerts and maximized the intrustion detection,
I'd like to hear about it.
<P>
Also if anyone has a YARD or other rescue disk builder that is customized
for creating write-protected tripwire boot/root diskette sets (for
periodic integrity auditing of Linux systems) I'd like to see a step-by-step
Mini-HOWTO or tutorial (maybe as a submission to Linux Gazette).
<P>
-- Jim
<p><hr><p>
<!--================================================================-->
<a name="karsh"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Applix Spreadsheet ELF Macro Language
</h3>
<P> <B>
From: Paul T. Karsh ITTC-237B 8-286-xxxx, <A
HREF="mailto:karchpte@acm.org">karchpte@acm.org</A>
</B> <P><B>
I happened on the Linux Gazette in the process of searching
for some information on "scripting" macros in the Applixware
spreadsheet. Although this is not strictly a Linux question,
I hope you can help me with some "pointers" (links ?) on how to learn
this language. The Applixware help is no help and the company
at which I consult does not have the on-line Applixware books nor
the hardcopy "macro" manual.
</B> <P>
<img align=bottom alt=" " src="../gx/ans2.gif">
I played with Applixware a little bit -- but was highly
discouraged to find that its file conversion package
couldn't handle more recent versions of MS Word and Excel.
That was my main interest in the product since I occasionally
get file attachments in these proprietary formats -- and
sometimes they are potential customers.
<P>
As for the issue of learning this Macro language without
having the appropriate documentation. I would ask your
client where their manuals and/or installation CD is --
if they can't produce it and are unwilling to order a
replacement then I would question their decision to use
the product.
<P>
Applixware is a commercial product. Assuming this is
on a Linux system you'd probably want to contact Red Hat
Corporation to order replacement manuals (I think RH is
the sole Linux distributor for Applixware -- just as
Caldera is the sole distributor for the Linux version
of WordPerfect).
<P>
If they have the installation CD -- borrow it and install
its online documentation on some system somewhere (long
enough to get the information your need). Be sure to remove
that installation unless the appropriate licensing arrangements
are made, of course.
<P> <B>
<img align=bottom alt=" " src="../gx/ques.gif">
Is there somewhere on the net (FTP or anything) where I can get an intro
to this? I tried the Applixware site; it just seems to be page after
page of PR.
</B> <P>
<img align=bottom alt=" " src="../gx/ans2.gif">
I would like to see far more technical content on their
web site as well. (The same desire applies to other hardware
and software company sites).
<P>
-- Jim
<p><hr><p>
<!--================================================================-->
<a name="geene"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Answer Guy Issue 18 -- Procmail Spam Filter
</h3>
<P> <B>
From: Anthony E. Geene, <A HREF="mailto:agreene@pobox.com">
agreene@pobox.com</A>
</B> <P><B>
I'm not a procmail user, but I've found that most spam is sent using
envelope addresses, the standard recipient headers are not addressed to
the actual recipient. So I set up filters to catch my mailing list mail
and any mail that is addressed to a list of my vailid addresses. Other
mail is put elsewhere for later review.
</B> <P><B>
Such a method is relatively simple and would catch all but the
more sophisticated spammers.
</B> <P>
<img align=bottom alt=" " src="../gx/ans2.gif">
It is a good suggestion. It doesn't work if you have
some people that prefer to Bcc: you (use "blind carbon
copies"). Naturally many people's mail user agents
(MUA's) like elm, pine, etc don't have obvious options for
Bcc:'s -- others do (and most Unix/Linux MUA's allow
some way to do it -- even if it isn't *obvious*).
<P>
There are probably a number of other "false positive"
situations. As you say most automated mailing lists
have headers that would trigger on your criteria. The
obvious response to these problems is to make a list of
all the exceptional cases (of which you are aware) and
add appropriate rules to precede your anti-spam filter.
<P>
In addition it is important to ensure that your disposition
of apparently bogus messages is a refile to a specific
mail folder. You don't want to file it to /dev/null!
<P>
As you check your "probably junk" folder you can manually
refile the exceptions -- and optionally add new rules to
"pre-approve" lists of your favorite correspondents.
<P>
Note: if you keep a list of correspondents and a list of
known spammers, and you write a recipe to check the list
you may be concerned about the amount of time spent in
'grep'. Here's a hint: keep the list sorted and use the
'look' command.
<P>
(The advantage of 'look' is that it does a "binary" search
(think about successive approximation to "zero in on" the
desired lines) on a sorted file -- and returns the lines
that match. While the overhead of 'grep' grows in a linear
fashion (the search doubles in time as the file doubles
in size) that of 'look' grows much more slowly (it's
proportional to the square root of number of records/lines
in the file). Similar results would be attained if one
used 'dbm' hashes (indexes) -- but there is greater overhead
in programming (Perl offers modules to support dbm, gdbm,
ndbm and other hashing libraries -- it also has much higher
load time overhead as a result of it's generality).
<P>
The point is that even on a small file (100 lines) I
can see about a 10% difference in overhead. After a
few thousand lines the difference is substantial
(grep takes twice as long to run).
<P>
None of this matters much on your personal workstation
which has only one active user and receives a couple
hundred e-mail items per day. However -- if you're
filtering on the company mailhub, or at your ISP's
location -- it's worth it to reduce your impact.
<P>
-- Jim
<p><hr><p>
<!--================================================================-->
<a name="geene2"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Great Procmail Article!
</h3>
<P> <B>
From: Anthony E. Geene, <A HREF="mailto:agreene@pobox.com">
agreene@pobox.com</A>
</B> <P><B>
I read your procmail article in issue 14 of the Linux Gazette. It was
the best explanation of how procmail works that I've seen yet.
</B> <P><B>
I just wanted to say Thanks,<BR>
Anthony,
</B> <P>
<img align=bottom alt=" " src="../gx/ans2.gif">
Thanks for the feedback. BTW there is a new article on
use TDG (The Dotfile Generator) as a GUI front end for
creating procmail scripts. I haven't finished reading
it yet -- but it looks pretty good to me.
<P>
In your earlier mail you mentioned that you aren't using
procmail yet. This article on TDG and my explanation of
what's going on "under the hood" may yet change that.
(Also, somewhere on that morass of half-baked pages that
I keep as a "website" are some links to other procmail
and mail filtering resources).
<P>
-- Jim
<p><hr><p>
<!--================================================================-->
<a name="sindona"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Linux Cluster configuration
</h3>
<P> <B>
From: Antonio Sindona, <A HREF="mailto:Antonio.Sindona@trinacria.it">
Antonio.Sindona@trinacria.it</A>
</B> <P><B>
I'd like to create a *Linux cluster configuration* to have some degree of
fault-tolerance (Linux normally works ... hardware not always ! ;-) ). Do
You know if somebody tried to develop something to solve this problem ?
</B> <P>
<img align=bottom alt=" " src="../gx/ans2.gif">
The first place I'd look for info on fault tolerance for
Linux would be:
Linux High Availability HOWTO<BR>
http://sunsite.unc.edu/pub/Linux/ALPHA/linux-ha/High-Availability-HOWTO.html
<P>
Then take a look at:
<P>
Linux Parallel Processing HOWTO<BR>
http://yara.ecn.purdue.edu/~pplinux/pphowto.html
<P>
... and:
<P>
MP and Clustering for Linux<BR>
http://linas.org/linux/mp.html
<P>
One of the most famous Linux parallel computing projects (which has
been written up in the _Linux_Journal_ among other places) is the
Beowulf Project:
<P>
http://sdcd.gsfc.nasa.gov/ESS/linux.html
<P>
After you've been overwhelmed by reading all of that you can
slog through all of the links at:
<P>
Linux Parallel Processing Using Clusters<BR>
http://yara.ecn.purdue.edu/~pplinux/ppcluster.html
<P>
.... which include links to some classic Unix projects like
"Condor," PVM, and MPI.
<P>
After reading all of those you'll undoubtedly decide that Linux
is years ahead of Microsoft in the field of clustering. (MS'
"wolfpack" project is still vaporware last I heard). However,
lest we grow complacent we should consider some features that Linux
needs to compete with mainframe and mini clustering technologies
(like those in VMS, and the ones that HP managed to eke out of
their aquisition of Apollo -- when they gutted DomainOS, from what
I hear).
<P>
The two features Linux needs in order to attain the next level
of clustering capacity are "transparent checkpointing" and
"process migration."
<P>
"Transparent checkpointing" allows the kernel to periodically
take a comprehensive snapshot of a process' state (to disk or
to some network filesystem) and allows the OS to restart a
process "where it left off" in the event of a system failure.
<P>
(System failures that damage the checkpoint files notwithstanding,
of course).
<P>
"Process Migration" allows a node's kernel to push a process
onto another (presumably less heavily loaded) system. The process
continues to run on the new system without any knowlege of the
transition.
<P>
At first it seems like "checkpointing" would cost way too much
in performance. However, it turns out that relatively little
of your system's RAM has been modified from the disk images
(binaries and libraries) in any given time frame. I've heard
reliable reports that this has almost trivial overhead on a
Unix/Linux like system.
<P>
It's easy to see how "checkpointing" is a necessary feature
to support process migration. However, it's not enough. You
also need mechanisms to allow the target kernel to give the
incoming process access to all of the resources that it had
allocated (open file descriptors, other interprocess channels,
etc). For Unix like systems you also have to account for
the process structure (the PID of the process can't change)
-- and there has to be some implicit inter-node communications
to maintain the process groups (to get a process' exit
status to its parent and to allow members of a process group
to get status and send signals to it.
<P>
There have been a number of operating systems that have implemented
checkpointing and process migration features. Chorus Mi/X, Berkeley
Sprite and Amoeba (a project that the father of Minix, Andrew S.
Tanenbaum, collaborated on) come to mind.
<blockquote>
(see http://www.am.cs.vu.nl/ for info on Amoeba,
http://HTTP.CS.Berkeley.EDU/projects/sprite/ for
Sprite, and http://www.chorus.com for Chorus Mi/X
info).
</blockquote>
One Unix package that is supposed to offer these features is Softway Ltd's
Hibernator II. Just SGI and a Fujitsu mainframe version are supported.
This is probably an expensive commercial package and we shouldn't
hold our breath for a Linux port.
<P>
* http://softway.com.au/softway/products/hibernator.html
<P>
The MOSIX project also supports transparent process migration (imagine
that copy of emacs being moved from one overloaded CPU to an idle
machine while you were using it). It is currently available on
BSD/OS. However we're in luck! As I was typing this and checking
my URL's and references I noticed the following statement on their
pages:
<P>
``MOSIX for Linux (RedHat) is now under development''
<P>
(Yay!).
<P>
You can read more about MOSIX (and see this note yourself) at:
<P>
http://www.cs.huji.ac.il/mosix/
(Hebrew University, Israel)<BR>
http://www.cnds.jhu.edu/mirrors/mosix/txt_main.html
<P>
One OS project that I've been keeping my eye on for awhile has been
EROS (http://www.cis.upenn.edu/~eros/). This isn't widely
available yet -- but I have high hopes for it. It will use a
"persistence" model that implicitly checkpoints the state of the
entire system (all processes and threads).
<P>
EROS is not "Unix" though it should eventually support a Unix/Linux
compatible subsystem (called Dionysix). The major difference is that
EROS is a pure "capabilities" system. ``Capabilities'' are the key to a
security model that is much different than the traditional identity/group
(Unix), process privileges (VMS and Posix.6), and ACL (NT, Netware,
etc) that are common in other operating systems. Read Mr. Shapiro's
web pages for more info on that.
<P>
I personally think we (in the Linux community) have quite a bit
to learn from other operating systems -- their strengths and
their weaknesses. To anyone of us who would say "But those are
just obscure systems. Nobody is running those!" I would point
out that millions of PC users still have that same reaction to
Linux.
<P>
So, to learn *far* more than you ever wanted to know about
operating systems *other* than DOS, MacOS, and Unix take a
look at the links on my short page about OS':
<P>
http://www.starshine.org/jim/os/
<P>
-- Jim
<p><hr><p>
<!--================================================================-->
<a name="holloway"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
IP Masquerading/Proxy?
</h3>
<P> <B>
From: Jack Holloway
</B> <P><B>
Ok... I'm alittle foggy on the terminology... if I have a machine on an
ethernet network that is hooked to the internet, and I want all of the other
machines on the network to connect to the internet THROUGH the machine
connected to the internet, I need to use IP masquerading or proxy server
stuff?
</B> <P>
<img align=bottom alt=" " src="../gx/ans2.gif">
You can use IP Masquerading and/or any sort of proxy systems.
<P>
IP Masquerading is a particular form of NAT (network
address translation).
<P>
The one machine (your Linux box) that is connected to
your LAN and to the Internet is the "router" or "gateway."
("routers" work at the "transport" layer, while "gateways"
work at the "applications" layer of the OSI reference model).
(More on that later).
<P>
One "real" (IANA issued) IP address is assigned to the
"outer" interface and attached to the Internet (through
your ISP). This will typically be a PPP link through your
router/gateway's modem -- though it might be any network
interface that you can get Linux to use.
<P>
One the other interface (typically an ethernet card) you
assign one out of any of the "private" or "reserved for
disconnected networks" IP address ranges as defined in
RFC1918 (previously in RFC1597 and 16??). These RFC1918
addresses are guaranteed to never be issued to any
Internet host (so those of use using them on our networks
will never create an ambiguity with *our* router by attempting
to access a machine *outside* our network that has an IP
address that duplicates one *inside* of our network).
<P>
The RFC1918 address blocks are:
<PRE>
10.*.*.* (one class A net)
172.16.*.* through 172.31.*.* (16 class B's)
192.168.0.* through 192.168.255.* (255 class C's)
</PRE>
You can pick any of those RFC1918 address blocks and
you can subnet them anyway that's convenient. I use
192.168.64.0 for my home LAN.
<P>
Within my LAN I use the .1 address (192.168.64.1) for my
Linux gateway/router's ethernet -- it gets its other (real)
IP address dynamically from my ISP when 'diald' establishes
a connection (diald is a daemon that automatically invokes my
ppp connection whenever traffic routing to the network is
required -- I actually have another RFC1918 address assigned
to the SLIP connection that diald uses for internal purposes).
I run a caching nameserver on this box (which we'll call "gw").
<P>
All systems on my LAN execute a line like the following:
<PRE>
route add -net 192.168.64.0 eth0
</PRE>
... in their rc scripts at some point. This configures
them to all agree where packets for this network go.
This is called a "static" route.
<P>
I then point the /etc/resolv.conf on all of the "client" machines
on my LAN to "gw" and add a default route to each of them that
looks like:
<PRE>
route add default gw 192.168.64.1
# other traffic goes to host named "gw"
</PRE>
(the "client" machines don't have to be Linux and don't
have to have any special support for IP Masquerading --
you just assign them IP addresses like 192.168.64.2, etc.
to each of them).
<P>
In the "gw" server I have the kernel compiled with masquerading
and "forwarding" support enabled (of course). I don't put in
the default static route -- that would be a loop. "gw" also
has a different /etc/resolv.conf file -- one that points to
a couple of my ISP nameservers.
<P>
Note: One trick I've learned about resolv.conf files --
You only get three nameserver entries (in most versions of
the bind libraries) -- so I repeat the first and the last
one. When a query times out (for a client) it moves to the
second nameserver. Meanwhile the first nameserver still
has a good chance of getting a response (DNS over today's
busy Internet times out more often than nameservers fail).
So, a timeout on the second nameserver leads to a repeat
request on the first one -- which has probably received
and cached a response by this time. I could explain that
in more detail -- but the real gist is: try it. It helps.
<P>
Now, back to masquerading:
<P>
All it takes for masquerading to work is to run the command
<PRE>
LAN="192.168.64.0/24"
ipfwadm -F -a accept -m -S $LAN -D 0.0.0.0/0
</PRE>
... which means:
<P>
use the "IP firewall administrative" program to
make the following change to the "forwarding" (-F)
table:
<blockquote>
add/append (-a) a rule to accept for
masquerading (-m) any packet from (-S
or "source address") my LAN (which is a
shell variable I defined in the preceding
line) that is going to (whose "destination"
-D) is anywhere (0.0.0.0/0).
</blockquote>
Here's how that works. When the kernel receives a packet
that's not destined for the localhost (the gateway itself)
it checks to see if forwarding is enabled, then it looks in
the routing table to see where the packet should go. My
gateway's default route is pointing to the sl0 interface
(the SLIP interface that diald maintains to detect outgoing
traffic) -- when diald detects traffic on sl0 -- it
runs my PPP connection script which changes the default
route to point to my ISP's routers (which is part of the
information that's negotiated via PPP along with my
dynamic IP address). Now the packet is "forwarded" from
interface to the other. Assuming that the packet came
from my LAN (via the ethernet card in "gw" the kernel's
packet filtering ("firewall") code takes over.
<P>
ipfw inspects the packet to see if it was part of an
existing TCP session (part of a connection that it has
already been working with). If it is than ipfw notes
the TCP "port" that this session is assigned to, otherwise
ipfw just picks another port. If it picks a new port it
adds an entry to it's masquerading table that records the
packet's original source address and source port. The
"client" machine on my LAN is expecting any reply packets to
come back to the appropriate source port (which is how it
knows which process' "socket" to write the reply packets to)
-- ipfw then re-writes the packet headers, changing the source
address to match the one on ppp0 (the "real IP address for
which my ISP knows a route), and changing the source port to
the one it selected.
<P>
When ipfw receives reply packets the kernel routes them to
sockets which ipfw owns (the source port on my outgoing
packets becomes the destination port on the reply packets).
ipfw then looks that socket up in its table, retrieves the
*original* source addr and port (for the outgoing packet that
generated this reply) rewrites the destination fields (on the
*reply* packet). Finally the (now re-written) packet is
routed to the LAN.
<P>
Effectively IP Masquerading makes a whole LAN full of machines
look like one really busy one to the rest of the Internet.
While a typical workstation might only have a few dozen
active network connections available, a masquerading gateway
might have hundreds or thousands. As a practical matter
the TCP/IP protocol provides a 16 bit field for "ports" and
Most Unix systems can't handle more than a few thousand
concurrent open connections (sockets) and file descriptors.
(This has to do with the tables that the kernel allocates
for the data structures that manage all this -- regardless
of whether masquerading is active or not). Luckily you're
unlikely to have enough bandwidth to approach Linux'
capacity.
<P>
I'm sorry for the length of that description. Note that
it is purely conceptual (I've never read the code, I've
just deduced what it must be doing from what I know of
how TCP works).
<P> <B>
<img align=bottom alt=" " src="../gx/ques.gif">
Ouch! That's a big question there! Ok, firstly, do own IPs for every
machine on your network? (That is, do you have an internet unique IP for
each machine) If so, all you want is routed. If you don't, then to
</B> <P>
<img align=bottom alt=" " src="../gx/ans2.gif">
'routed' is deprecated. In addition he doesn't need routed
or gated to talk to his ISP (and almost certainly can't
use it with them -- they won't listen to his routes unless
he goes out and gets an AS number and negotiates a contract
for "peering" with them which would absurd unless he were
becoming a multi-home ISP or something like that).
<P>
The case where routed or gated makes sense is with his
own internetwork of LAN's. If he has several ethernet
segments and is moving systems around them frequently
(or adding new IP devices to them) then it would be
be useful. For simpler and for more structured LANs
(each ether segment gets a subnet -- a global, static
routing table is distributed to all routers) you don't
need or want 'routed' or 'gated'.
<P>
If he had a block of ISP (or IANA) issued IP addresses,
his ISP would have to include routing to them (they
don't make sense otherwise). Usually this amounts to
some static routes that they maintain in their systems
-- specifically some entries that are invoked whenever
your system authenticates on one of their terminal servers
or routers.
<P>
You don't have to run any software on your end to make
use of this routing. (That's a confusing statement --
you have to run PPP or SLIP to connect to them -- but
once you're connected they will route packets to you
even if your routes back to them are completely missing).
<P>
As I've described above -- you just have to have your
own LAN routing set up properly. That means that each
system on your LAN has "-net" routes unto your ethernet
and a "default gw" route to your router/gateway (masquerading
host).
<P> <B>
<img align=bottom alt=" " src="../gx/ques.gif">
browse the web you can use a proxy server(which looks to the outside world
as if only the proxy is actually on the net.). If you want to telnet etc.
out, you will need IP-Masquerading, which isn't the most reliable way of
doing things. ask me further in email if you need more detail!
</B> <P>
<img align=bottom alt=" " src="../gx/ans2.gif">
I disagree with several points here. Both masquerading *and*
proxying look like "only the proxy is actually on the net."
-- because only the router/gateway has an IP address with
valid Internet routes. The rest of your LAN is "hidden"
(behind your "gw") because those IP addresses don't have
valid Internet routes. The are IP addresses but they are
not *Internet* addresses!
<P>
Proxying is an applications layer solution. Masquerading
and NAT are transport layer. The difference is what
data structures the software is dealing with.
<P>
At the network layer we're working with "data frames." This
is what an ethernet bridge or switch uses -- the MAC (BIA)
addresses. That's also the layer at which ARP (address
resolution protocol) works. It's how one host finds
finds the ethernet card address of another system that's
on the same LAN (how our client machines "find" our router/gw).
<P>
At the transport layer we deal with packets. These have IP
addresses (as opposed to the MAC -- media access control --
addresses in the ethernet "frame" header). This is where
the masquerading happens. As I've described masquerading
involves a relatively "dumb" (mechanical) bit of packet
patching with some table reference and maintenance.
Technically there are some details I left out -- like
recomputing the packet checksums.
<P>
The problem is that the transport layer conveys no information
about the applications protocol for which it is a carrier.
For "normal" TCP protocols (like HTTP and telnet) this is
no problem. However, FTP and a few other protocols do "bad"
things. In particular an FTP session consists of *two* TCP
sessions (a control session which is initiated from the client
to the server) and a data session which is initiated from the
server back to the client! The IP address and port to which
this "return connection" goes is passed to the server via
the control connection. This last detail has caused more
firewall designers and admins to rip out their hair than
all the cheap combs from China. In the context of masquerading
it means that the masquerading server must monitor the
*data* (the stuff in the payloads of the packets) and make
some selective patches therein. In the other cases we only
touched the headers of each packet -- never the contents of
their payloads.
<P>
So, this is the part of Masquerading that is unreliable.
Linux IP Masquerading is by no means the only flavor --
though it's probably the most widely used by now. Linux
as several modules for dealing with unruly protocols --
so the usually work.
<P>
However, I've found it more reliable to use the TIS FWTK
ftp-gw (Trusted Information Systems http://www.tis.com,
Firewall Toolkit). This is a proxy.
<P>
Proxy packages work at the applications layer. You have
to have support for each applications protocol (http, ftp,
telnet, rlogin, smtp, etc) that you want to allow "through"
your firewall. They come in two forms: SOCKS and FWTK
(There are many of them besides these -- but all of them
follow one *model* or the other).
<P>
In the FWTK model the user opens his or her initial
connection to the firewall (I 'ftp' to gw.starshine.org).
The firewall (gateway) is running the FWTK proxy *instead
of* (or *in addition to*) the normal server (ftpd). If
it is "in addition to" than one or the other must be on a
different port or using a different IP Alias on the machine
(more on that later). Now my FTP server (ftp-gw) prompts
me to "login"
<P>
For a normal FTP server I'd type my name (or "ftp" or "anonymous").
For ftp-gw I'm trying to go *though* this machine and unto
one that's on the other side (on the Internet). So I have to
provide more information. So I type:
<P>
ftp@sunsite.unc.edu
<P>
... or
<P>
webauthor@www.svlug.org
<P>
... or whatever. The gateway ftp server then opens a connection
to my target (everthing *after* the @ sign) and passes my
name (everything before the @ sign) to *its* login prompt.
<P>
The TIS FWTK comes with a number of other small proxies --
and most of them work in a similar fasion. (There are
also options to limit *who* can access *what* and *when*
(via administrator edited access control lists).
<P>
The key point here is that FWTK doesn't require any special
client software support. The users have to be trained how
to traverse the firewall and the have to remember how to do it.
<P>
FWTK is only appropriate for relative small groups of technically
savvy users (who are easy to train in this and won't make the
sysadmin's life a constant hell of walking everyone through this
extra connectivity step).
<P>
SOCKS has a model that works for larger groups of less savvy
users. However, it requires that you install SOCKS aware
versions of your client applications. So you have to replace
your normal telnet, ftp, rlogin, etc with a "socksified"
version. In many cases it is possible to effectively
"socksify" all of your client utilities by replacing a shared
library (Unix/Linux) or a DLL (Windows). Many commercial
TCP clients and utilities are built with SOCKS support
(Netscape Navigator and Communicator are prime examples).
I think the Trumpet shareware utilities for Windows are
another.
<P>
The hassle is installing and configuring this software on every
client system. However, the advantage is that none of the users
has to remember, or even know, about the firewall. The SOCKS
applications will automatically negotiate sessions through the
firewall.
<P>
There are some protocols that are inherently easy or even
unnecessary to proxy. For example DNS doesn't need to
be proxied. You run your caching copy of named and let
all of the client machines talk to and trust it. This
gives a great performance boost to most of the clients
and saves quite a bit of bandwidth on the critical link
to the ISP. There is no reason that I can think of not
to run a caching nameserver somewhere on your Internet
connected LAN.
<P>
HTTP is a protocol that benefits quite a bit from proxying.
It is trivial to add caching features a web proxy -- and
I think just about all of them do so.
<P>
SMTP is a protocol that doesn't need proxying (from the
standpoint of the clients on your LAN). You configure
an internally accessible system to accept mail and
it will relay it to your gateway via whatever means
you configure. A typical model would be that outgoing
mail is collected on an internal hub, which is configured
to relay it to the external gateway, which, in turn,
relays it to the ISP and on to the world. To see what
this looks like read the "Received" headers in some of your
mail.
<P>
The externally visible mail gateway can route mail
back to the internal hub -- which can run POP and/or
IMAP servers for the clients to use to actually get
their mail. (You could have the internal hub route
all of the mail directly to people's desktops via
SMTP too.
<P>
The reason you generally don't need proxying for
SMTP is that most sites use some form of masquerading
(mail appears to come from the "domain" rather than from
a particular host whithin the domain). FWTK includes
smapd -- and there is an independent and free smtpd
which act as proxies for sendmail. Here the intend is
to have a small simple program receive mail and
pass it along to the larger, vastly more complicated
'sendmail' itself. (I don't want to get into the
raging debates about sendmail vs. qmail etc -- suffice
it to say there are many alternatives).
<P>
Note that masquerading and proxying are not mutually
exclusive. I use masquerading and I have ftp-gw and
squid (caching web service) installed. I could
also install SOCKS on the same gateway.
<P>
Incidentally I mentioned that it's possible to run ftpd
and ftp-gw on the same machine without putting them on
different ports. Here's two ways of doing that:
<P>
IP Aliasing method:
<ol>
<li> You install ftpd and ftp-gw
<li> You create an IP Alias (you add an extra address
to your gateway system's internal interface with
a command like:
<PRE>
ifconfig eth0:1 192.168.64.129
</PRE>
<li> You configure your TCP Wrappers to virtual host
a service by adding a line like this to your
/etc/hosts.allow file:
<PRE>
in.ftpd@192.168.64.129: 192.168.64. : twist /usr/local/fwtk/ftp-gw
</PRE>
This will "twist" any ftp request *to that IP alias*
into an ftp-gw session. FTP requests to any other
interface address will be handled in the usual way
(tcpd will launch the ftp daemon that's listed in
inetd.conf).
</ol>
That's all there is to that method. Note that you can
to other interesting things with this sort of virtual
hosting, if you're clever.
<P>
Loopback Twist method:
<ol>
<li> Install ftpd and ftp-gw (as you would for
the other method).
<P>
<li> Configure tcp wrappers to allow normal ftp
access *from* the localhost address (127.0.0.1)
<P>
<li> Configure tcp wrappers to twist any other
ftp requests into ftp-gw
</ol>
That looks like this (in the /etc/hosts.allow file):
<PRE>
in.ftpd: 127.0.0.1 : ALLOW
in.ftpd : ALL : twist /usr/local/fwtk/ftp-gw
</PRE>
WARNING! This second line would allow *anyone*
(from inside or outside) of your LAN to access the
proxy. However, ftp-gw reads a file --
/usr/local/etc/netperm-table according to the way I
compiled mine -- to determine who is allowed to access
each of its proxy services.
<P>
So, this line is neither as dangerous as it looks
nor as safe as it should be. Changing it to:
<PRE>
in.ftpd : LOCAL : twist /usr/local/fwtk/ftp-gw
</PRE>
... is safer and more appropriate.
<P>
One key point here is that you can use proxies on
your masquerading route/gateway to allow access from
the "outside" back *into* services inside your LAN.
Usually you want to prevent this (the whole point of
a firewall). However you can use tcpd and netperm to
allow specific 'friendly' networks to get to servers
on one of your LAN's, despite the fact that there are
no routes directly to those machines.
<P>
This brings us back to other forms of NAT. I mentioned
at the get-go that masquerading is one form of NAT. It
specifically involves a "many to one" arrangement.
(The "many" clients on your LAN appearing as "one" connection
to the Internet).
<P>
Another form of NAT is "many to many" -- where you have a
table translations. Thus each of your systems might be
configured to use one address, and be translated to appear as
if it came from anoter. I personally don't see much use for
this arrangement. The one case I could see for it might be
if you had a net of devices that you couldn't renumber, which
had "illegal" or "invalid" addresses.
<P>
One other form of NAT involves a different "many to many"
translation -- its not currently available for Linux but
it's used in the Cisco Local Director product. This is a
trick for doing IP level load balancing. You have a
"reverse masquerade" host accept requests to "a" busy
server (one service on one IP address) and you have it
masquerade the session to any of multiple "inside" machines
that have the same service and content available.
<P>
For load balancing it's trivially easy to use DNS "round
robin records" -- so I don't see much application for this
form of NAT either.
<P>
Anyway -- that's all I have the energy to type for now.
<P>
I hope this explains the terms and concepts and gives you
enough examples to set up what you want. For the most part
you can just use the one magic ipfwadm command to "turn on"
masquerading. The rest is just the configuration of your
network and of your ISP connection -- which you've presumably
already done.
<P>
-- Jim
<!--================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, James T. Dennis <BR>
Published in <I>Linux Gazette</I> Issue 27 April 1998</H5></center>
<P> <hr> <P>
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<H4>
"Linux Gazette...<I>making Linux just a little more fun!</I>"
</H4>
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<!--===================================================================-->
<center>
<H2>Autologin with mingetty</H2>
<H4>By <a href="mailto:kodis@kodis.jagunet.com">John Kodis</a></H4>
</center>
<P> <HR> <P>
In Issue 26 of the Linux Gazette, Todd Blake,
tbb@enterprise.aacc.cc.md.us, wrote in to ask:
<blockquote> <I>
"I like most people am the only person to use my linux system at
home. What I'd like to do is when my system is done booting to
have me automatically login as my main user account (not as root
though) on one virtual console (the first) and leave all other
consoles and virtual consoles alone, so that someone telneting in
will get a login prompt like normal, just that I won't. I'd still
like the other VC's have logins for others to login and other
reasons. I've tried just putting /bin/sh in /etc/inittab and that
didn't work, and I'm stumped. Does anyone have any ideas on
this?"
</I> </blockquote>
I was in the same situation. I saw this question come up regularly in
various newsgroups, but never with a satisfactory solution being
proposed. Recently I came up with a solution that does just what
Mr. Blake requested. I did this by making a few changes to Florian
LaRoche's mingetty program, which is used issue the login prompt on
virtual consoles in most Linux distributions. These changes allow a
user to be automatically logged onto the console terminal as soon as
the system boots. I got the idea for this patch after reading about a
similar feature provided on SGI's Irix operating system.
<P>
Here's the description of the autologin feature that I've added to the
mingetty.8 man page:
<blockquote>
<B>--autologin username</B>
Log the specified user onto the console (normally
/dev/tty1) when the system is first booted without
prompting for a username or password.
</blockquote> <P> <blockquote>
When the autologin option is supplied, mingetty
will check that the controlling terminal is the
console (normally /dev/tty1), that a reasonable
username has been supplied, and that this is the
first autologin request since the system has
booted. If all of these conditions have been met,
a request for an unauthenticated login is passed to
the login program. Otherwise, a normal interactive
login is performed.
</blockquote> <P> <blockquote>
The login program may deny the request for an unau-
thenticated login. Typically this will happen when
the user is root, has a UID of 0, or whenever a
normal interactive login would be denied due to the
access restrictions specified in the nologin,
usertty, or securetty files.
</blockquote> <P> <blockquote>
Only a single autologin request will be issued
after a system boot. If the automated login
request is denied, or if the user logs out,
mingetty will revert to performing normal interac-
tive logins for all subsequent login requests.
</blockquote> <P>
I've placed unified diffs against the mingetty-0.9.4 version of
mingetty.c and mingetty.8 on my web page at
http://www5.jagunet.com/~kodis/. The patched version of mingetty logs
me in on the first virtual console when my computer first boots, while
leaving all the normal Unix security measures in effect for all but
this one specific console login.
<P>
To use this patch, you'll have to first obtain the sources for the
mingetty program, preferably with any patches used in your Linux
distribution. After applying the patch file from my web page, you
will have to rebuild the mingetty program, and install it and the
patched mingetty.8 man page in the appropriate directories after
saving the original versions.
<P>
The inittab entry for the first VC will then have to be modified to
put the autologin feature into effect. In my /etc/inittab file, this
line now reads:
<PRE>
1:12345:respawn:/sbin/mingetty --noclear --autologin kodis tty1
</PRE>
Rebooting after making these changes will insure that init has spawned
the new version of mingetty, and if all is well, will automatically
log you on to the console.
<P>
Since I normally use X whenever I'm logged in at the console, I've
added the following few lines of code to my .zlogin and .bash_profile
scripts. This code queries "Start X [Yn]? " when initially logged in
from the first virtual console, and waits 10 seconds for a response.
Entering Y or allowing the timeout to occur results in X being
started. On exiting X, a similar timed query asking "Log out [Yn]? "
is issued, giving the option of logging out or being dropped into a
text console.
<PRE>
case `tty` in
/dev/tty[1])
echo -n "Start X [Yn]? "
expect \
-c 'stty raw' \
-c 'set timeout 10' \
-c 'expect -nocase n {exit 1} -re . {exit 0}'
if [ $? = 0 ] ; then
startx
echo -n "Log out [Yn]? "
expect \
-c 'stty raw' \
-c 'set timeout 10' \
-c 'expect -nocase n {exit 1} -re . {exit 0}'
if [ $? = 0 ] ; then
logout
fi
fi
echo
;;
esac
</PRE>
These few changes combine to make getting logged on and running X on a
Linux box as easy as turning the power on. Here's hoping that this
proves useful for Mr. Blake and any of your other readers who find
themselves in this situation.
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, John Kodis <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
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<H4>
"Linux Gazette...<I>making Linux just a little more fun!</I>"
</H4>
<P> <HR> <P>
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<center>
<H1>Checking Out SPARC-Linux with SLXT</H1>
<H2>Grab a bargain SPARC</H2>
<H4>By <a href="mailto:gaijin@pobox.com">John Little</a></H4>
</center>
<P> <HR> <P>
There are lots of Sun SPARCstations coming onto the second-hand market, or
even being given away for free, nowadays. The attractions of a SPARC
are numerous. The graphics resolution of a typical SPARCstation is 1152x900
(either monochrome, 8-bit or 24-bit colour), all machines have built-in
ethernet controllers and all come with on-board SCSI.
<P>
Unfortunately, there are also a couple of drawbacks. It's not unusual for
these machines to come onto the market with only very small internal disks
(dual 100MB or a single 200MB is fairly common), or even minus disks
completely and, as anyone who has bought one recently will tell you, SCSI
disks are still more expensive, megabyte for megabyte, than their IDE
cousins.
<P>
There's also a SPARC-Linux specific problem, commonly referred to
as the "IPC slowdown bug" which, as the name suggests, plagues some
of the low-end Sun4c architecture machines, especially the IPC,
SPARCstation 1 and 1+ models. This doesn't affect all machines
(which is one of the reasons that a fix is proving difficult to
find), but on those which it does, even simple operations such as
an "ls /etc" can take several minutes. It's the computing equivalent
of that nightmare which everyone has had at one time or another
where you're trying to run away from something horrible, through
waist-deep, sticky treacle.
<P>
So, if your SPARCstation comes without a disk, or you load SPARC-Linux and
your machine proves to be one of the ones susceptible to treacle, what can
you do?
<P>
<H3>Don't panic!</H3>
All is not lost. SPARCstations make excellent Xterminals.
As already mentioned, they come equipped for the job with on-board ethernet
and high resolution graphics.
Even the most treacle-bound IPC will provide adequate performance
for most users when served by an i386 level machine and absolutely
stunning performance when served by a machine of Pentium-level
performance. The secret is, of course, that application processing
is offloaded onto the server, while the SPARCstation runs only a
cut-down kernel and the Xserver process. This is basically a
SPARC-Linux implementation of Seth Robertson's Xkernel package.
The principal of operation is the same, but the binaries,
libraries and code are 100% Linux (it is important to note here
that there's no Sun code included in the package, so you do
<STRONG>not</STRONG>
need a Sun "Right To Use" software licence to run the
SPARC-Linux Xterminal package).
<P>
<I>
NOTE - People are frequently confused by the Xterminal concept and the
fact that when they log-in to an Xterminal they find themselves in a shell
on the server. Perhaps the easiest way to understand it is to think
of the Xterminal as simply being a display attached to the server (which,
in effect, it is) and of the Xterminal hardware as being a remote video card.
</I>
<P>
The
<A HREF="http://www2.gol.com/gaijin/Linux">SLXT package</A>
contains a SPARC-Linux, network-bootable kernel for sun4c and sun4m
architectures, as well as scripts to automate the installation
process and the administration of Xterminal clients. The scripts are
Linux specific, but the package can be installed manually (on
virtually any system which provides tftpboot and X support) in about
ten to fifteen minutes by an experienced system administrator. The
author has run SPARC-Linux Xterminal clients from Solaris servers,
as well as from a variety of Linux machines.
<P>
Because the kernel is cut down, it will run quite happily on a
machine which has only 12MB of main memory (an 8MB machine will
boot, but will eventually crash with "out of memory" errors). In
fact, because the system only runs the kernel and Xserver processes,
any more than about 24MB of main memory is wasted, as it will never
be accessed. The kernel is small because it does not contain any disk
or floppy drivers. This also means that the SPARC-Linux Xterminal
package can be booted on an existing, diskfull machine with no fear
of accidentally overwriting the filesystems, thus making it possible
to have the same machine boot, say, Solaris from an internal disk, or
come up as an Xterminal when booted over the net. Of course, at around
2.5MB, the SLXT package is also much easier to download than the full
SPARC-Linux distribution if you just want to check whether your system
will run the Linux kernel.
<P>
<H3>Booting SLXT</H3>
Before you can boot your SPARC client machine, you'll need to make a
note of the ethernet address (the
<I>add_xterm</I>
administration script will ask for this information). This is visible,
along with information on the boot PROM revision and memory size,
immediately after the power on selftest has completed. Your machine will
probably be set up to boot directly from disk, so you may need to hold
down the
<I>"Stop"</I>
and the
<I>"a"</I>
keys simultaneously to prevent the ethernet address from scrolling off
the screen (this key sequence is commonly referred to as an
<I>"L1-A"</I>
in Sun circles because the "stop" key is also the first key on
the left-hand keypad of a Sun keyboard).
<P>
After entering the ethernet address and choosing a hostname and IP address
for your client,
<I>add_xterm</I>
will update the configuration files and the ARP and RARP caches on your
server. You can then boot your SPARC client using
<I>"boot net"</I>
(from the
<I>"ok"</I>
prompt), or
<I>"ble()"</I>
(from the
<I>"&gt;"</I>
prompt), depending upon which revision of boot PROM your machine has.
<P>
The most common question asked about the SLXT boot process is
<I>"Why does it take so long to boot?".</I>
<BR>
The answer is that the machine is downloading a complete kernel
image from the server and then executing it, unlike a normal SunOS
or Solaris boot, where the bootstrap reads in a second-stage loader, which
in turn downloads the kernel. Be patient! Once the kernel is downloaded, the
time taken to start the Xserver process and display a login prompt is very
much shorter than the rest of a typical SunOS/Solaris boot. You'll need to
be very quick to catch a glimpse of the SPARC-Linux, beer-swilling penguin.
<H3>More Information</H3>
The SLXT package includes a
<A HREF="http://www2.gol.com/gaijin/Linux/SLXT_FAQ">FAQ,</A>
a
<A HREF="http://www2.gol.com/gaijin/Linux/CHANGES">CHANGES</A>
file and a
<A HREF="http://www2.gol.com/gaijin/Linux/slxt.lsm">package info</A>
file. Unfortunately, at the time of writing the version on SunSite had
not been updated for some time (the last update, along with dozens
of other packages, is still languishing in the Linux/Incoming directory).
The latest revision, along with documentation, should always be available
from the author's home site at
<A HREF="http://www2.gol.com/gaijin/Linux">http://www2.gol.com/gaijin/Linux,</A>
though.
<P>
<HR SHADE SIZE=5>
<H4>What do you need to run your SPARC as an Xterminal client?</H4>
<UL>
<LI> You must have your SPARCstation connected to a network on
which there is at least one other machine. This second, "boot
server" machine must have a minimum of 7MB of free space available
for the SPARC-Linux Xterminal package, and should have a complete
X11 tree. It can be anything from a standalone i386 Linux system
upwards (although it obviously makes sense to use a server which
is more powerful than the clients, especially where multiple clients
will be operating simultaneously).
<P>
<LI> Your SPARCstation must have at least 12MB of main memory (it will
boot with 8MB, but will crash with "out of memory" errors as soon as
you start using applications). In the same vein, because the client
machine only runs a Linux kernel and the X-server process, any more
than about 24MB of memory is a complete waste.
<P>
<LI> Your SPARCstation does NOT need a disk. There are no disk drivers
included in the kernel, so even if the machine has a hard disk
installed, it can not be accessed (this also means that it is quite
safe to use a diskfull system for testing).
<P>
<LI> Your SPARCstation must have a frame-buffer, monitor and keyboard.
</UL>
<P>
<HR SHADE SIZE=5>
The gzipped-tar file, for the current version,
<A HREF="http://www2.gol.com/gaijin/Linux/SLXT_0.5c.tar.gz"> SLXT_0.5c.tar.gz </A> is approximately 2.5MB
and will take up slightly more than 6MB when installed.
<P>
<HR SHADE SIZE=5>
<I>Last updated: $Date: 2003/02/03 21:50:18 $.</I>
<ADDRESS>
gaijin@pobox.com
</ADDRESS>
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, John Little <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
<!--===================================================================-->
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<H4>
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</H4>
<P> <HR> <P>
<!--===================================================================-->
<center>
<h1>EMACSulation</h1>
<h4>by <a href="mailto:emarsden@mail.dotcom.fr">Eric Marsden</a>
</h4>
</center>
<p><HR> <P>
<blockquote><small>
This column is devoted to making the best use of Emacs, text editor
extraordinaire. Each issue I plan to present an Emacs extension
which can improve your productivity, make the sun shine more brightly
and the grass greener.
</small></blockquote>
<p>&nbsp;<p>
<h2>Ediff: an Emacs interface to diff and patch</h2>
<blockquote><font face="Helvetica">
Never read that diff output again! <br>
Apply patches interactively! <br>
Merge with ease! <br>
</font></blockquote>
<p> <strong>Ediff</strong> is a powerful package by <a
href="http://www.cs.sunysb.edu/~kifer/">Michael Kifer</a> which lets
you browse through the differences between files and directories, merge
files which have been revised by coworkers, and apply patches
interactively. Let's start with the simplest use&nbsp;: eyeballing the
differences between two versions of a text file. Either type <tt>M-x
ediff</tt>, or from the menubar go to Tools -> Compare -> Two files
(yes, it's something else on the XEmacs menubar). Ediff will prompt you
for two files to compare, open them and ponder a bit (while running <a
href="http://www.new.ox.ac.uk/jargon/jargon_19.html#TAG468">diff</a> as
a subprocess). Emacs will open a small control window, and show you
something like this
<p> <img src="./gx/marsden/ediff-compare-two.gif"
alt="Comparison of two files [21 kB]"
width="538" height="587">
<p> (for the curious, the window manager is a slighly modified version of
Chris Cannam's almost-minimal <a
href="http://www.netcomuk.co.uk/~cannam/wmx.html">wmx</a>). Differing
lines --or <em>hunks</em> in diff parlance-- in the two files are
highlighted in grey, and you can step through them by typing <tt>n</tt>
(next) or <tt>p</tt> (previous) into the control window. The active
hunk is highlighted in color, with the exact words which differ
displayed in a separate color (this process is called refining, and is
done by Emacs itself, not by diff). Naturally Ediff works best when run
under a windowing system, but it does work in degraded mode in the
console.
<p> You can use all your normal keybindings in the two buffers being
compared; ediff-specific commands must be typed into the control panel.
To obtain help, type <tt>?</tt> while focus is in the ediff control
panel; it should warp into a reassuring help window something like
<p> <img src="./gx/marsden/ediff-help.gif"
alt="Ediff help window [7 kB]"
width="512" height="239">
<h3>Merging files</h3>
<p> Ediff can help you merge two files into a third file, a little like the
command-line tools <em>sdiff</em> and <em>merge</em>. Type <tt>M-x
ediff-merge</tt> to enter merge mode and be prompted for two filenames.
The Emacs frame will then be split in three, with the two files to be
merged side by side in windows named respectively A and B, above a
buffer containing their merge. It should look a little like <a
href="./gx/marsden/ediff-merge.gif">this</a> <i>(23 kB)</i>. The normal width of
your Emacs frame may be a little limiting for two files side by side;
you can type <tt>m</tt> to widen the frame.
<p> For each hunk you will then be able to choose which files to make
authoritative (ie which version to include in the merge). Type
<tt>a</tt> to choose the version in the buffer labelled A, <tt>b</tt>
for the other buffer, or <tt>+</tt> to include both (you can then edit
the merge buffer to select bits of both). You can also merge files with
respect to an ancestor, if for example two people have made independent
changes to a common original.
<h3>Interactive Patching</h3>
<p> We come to one of the most amusing uses of Ediff: applying a <a
href="http://www.new.ox.ac.uk/jargon/jargon_31.html#TAG1335">patch</a>
interactively from the comfort of Emacs. No more reading diffs ``by
hand'', no more fiddling around with rejects. Type <tt>M-x
ediff-patch-file</tt> to start the fun and be prompted for a patch file
and a filename. The Emacs frame will be split vertically with the
original file above, and the patched file below. You step from hunk to
hunk like for a diff, and can selectively restore certain regions from
the original file (undo parts of the patch) by typing <tt>a</tt>.
<p> Ediff also has an excellent integration with Emacs' <a
href="http://www.cl.cam.ac.uk/texinfodoc/emacs_18.html#SEC114">version
control interfaces</a>, which lets you compare different revisions of a
file. Open a file under version control (Emacs detects this
automatically) and type <tt>M-x ediff-revision</tt>; you will be
prompted for the two version numbers to compare. Ediff will check out
the two revisions and run diff on them. This seamless integration is
extended to remote and compressed files&nbsp;: your patches can be
compressed or on a distant machine, and Ediff will work things out all
by itself. You can even (not tested!) apply a gzipped remote patch to
an old version of a compressed file on another machine, so there.
<p> I've only described the most common uses of Ediff&nbsp;: it can also
compare three files (<tt>ediff3</tt>), compare buffers, compare
directory contents, and apply multi-file patches. Many aspects of the
presentation can be customized. It has a registry of current ediff
sessions which may be useful if you're a heavy user. Read the <a
href="http://subzero.campus.luth.se/FreeDocs/emacs-19.34/ediff/ediff_toc.html">online
documentation</a> to know all about it.
<blockquote>
<font face="Helvetica">
For they have entertained cause enough
<br>
To draw their swords. But how the fear of us
<br>
May cement their divisions, and bind up
<br>
The petty difference we yet not know. <br>
Be't as our gods will have't! It only stands
<br>
Our lives upon to use our strongest hands.
<br>
</font>
<p> William Shakespeare,
<a
href="http://the-tech.mit.edu/Shakespeare/Tragedy/antonyandcleopatra/antonyandcleopatra.2.1.html"><i>Antony
and Cleopatra</i></a>
</blockquote>
<h2>Feedback</h2>
<p> A few people pointed out to me that <strong>ffap</strong> is not
included with both Emacsen as I claimed in last month's column, but
only with GNU Emacs. XEmacs users can obtain the latest version from
Michelangelo Grigni (the author)'s <a
href="ftp://ftp.mathcs.emory.edu/pub/mic/emacs/">ftp site</a>. I also
incorrectly attributed a message from Christopher B. Smith to another
Linux user, Christopher B. Browne; my apologies to both Christophers.
<h2>Next time ...</h2>
<p> In the next issue I'll review emacsclient/gnuserv, a mechanism for
sending messages to a running Emacs process. Don't hesitate to contact
me at <tt>&lt;emarsden@mail.dotcom.fr&gt;</tt> with comments,
corrections or suggestions (what's <em>your</em> favorite
couldn't-do-without Emacs extension package?). <code>C-u 1000 M-x
hail-emacs</code> !
<p> <b>PS</b> : Emacs isn't in any way limited to Linux, since
implementations exist for many other operating systems (and some
systems which only halfway operate). However, as one of the leading
bits of <a href="http://www.open-source.org/">open-source</a> software,
one of the most powerful, complex and customizable, I feel it has its
place in the <i>Linux Gazette</i>.
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, Eric Marsden <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
<!--===================================================================-->
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<H4>
"Linux Gazette...<I>making Linux just a little more fun!</I>"
</H4>
<P> <HR> <P>
<!--===================================================================-->
<H1 ALIGN="CENTER">Evangelism: A Unix Bigot and Linux Advocate's Spewings</H1>
<P ALIGN="CENTER"><STRONG>By <A HREF="mailto:davew@cloudnet.com">David A.
Wagle</A></STRONG></P>
<P ALIGN="LEFT"></P><HR> <P>
<BR>
<H2><A NAME="SECTION00010000000000000000">
Table of Contents</A>
</H2>
<!--Table of Contents-->
<UL>
<LI><A NAME="tex2html2"
HREF="./wagle.html#SECTION00020000000000000000">Introduction: What's the Point?</A>
<LI><A NAME="tex2html3"
HREF="./wagle.html#SECTION00030000000000000000">A Conversion Story?</A>
<LI><A NAME="tex2html4"
HREF="./wagle.html#SECTION00040000000000000000">Why Linux Didn't Work</A>
<UL>
<LI><A NAME="tex2html5"
HREF="./wagle.html#SECTION00041000000000000000">What Learning Curve?</A>
</UL>
<LI><A NAME="tex2html6"
HREF="./wagle.html#SECTION00050000000000000000">The Problem and Three Solutions:</A>
<UL>
<LI><A NAME="tex2html7"
HREF="./wagle.html#SECTION00051000000000000000">Big Blue, Round Two</A>
<LI><A NAME="tex2html8"
HREF="./wagle.html#SECTION00052000000000000000">OK, Take A Deep Breath!</A>
<LI><A NAME="tex2html9"
HREF="./wagle.html#SECTION00053000000000000000">Putting one foot in front of the other</A>
</UL>
<LI><A NAME="tex2html10"
HREF="wagle.html#SECTION00060000000000000000">Why it isn't happening?</A>
<LI><A NAME="tex2html11"
HREF="wagle.html#SECTION00070000000000000000">Conclusion</A>
</UL>
<!--End of Table of Contents-->
<P>
<H1><A NAME="SECTION00020000000000000000">
Introduction: What's the Point?</A>
</H1>
<P>
Linux users are a notorious bunch. We tend to be vociferous OS
bigots of the first order. This is a trait that has served
the software community well. After all, if we were not that
way we would never have put the time and effort into
developing, deploying, and supporting the thing. But it also
a trait that has drawbacks. Some of these drawbacks are
serious, and effect our ability to present Linux as a serious
alternative to other, more prominent OS's (using the term, in
many cases, very loosely).
<P>
I'm not going to try to present the Linux alternative in
anything but a fair and honest way. That means I'm not going
to be talking about the possibility of loosing your job for
choosing Linux -- after all, that is not a problem that is
unique or limited to any one OS. The fact is that when you
choose the wrong tool for mission critical applications, you
should be called to task for that choice. This is regardless
of the OS's involved. Likewise I will not clamor on that
Linux is the one, true solution to all problems. Such a
statement, however much I'd like it to be so, is just as
foolish.
<P>
But, I wish to be clear that I will not have many good things
to say about those other OS's. For the most part they are
deserving of their poor reputations and of the scorn of any
true Linux afficionado. Still, there are better and worse
ways of promoting the <EM>Nearly</EM> One True OS that is Linux.
In this paper I would like to discuss some of those options.
<P>
<H1><A NAME="SECTION00030000000000000000">
A Conversion Story?</A>
</H1>
<P>
A few weeks ago I helped a friend (we'll call him Mike, being
that that is his name and I could care less about his
anonymity) install Red Hat 5.0 on his system. I made certain
that all the configuration files were properly tweaked for his
particular computer. I installed KDE, and made KDM the
default login method. I set up his networking, making sure
that it handled everything seamlessly in the background. Then
I showed him where the docs, howto's, mini-howto's and the
like were located. I spent time with him making sure he knew
how to use info, find, grep, ps, which, apropos and the man
pages. After a few hours of work and teaching, I went my
happy way convinced that another conversion to the Linux way
(tm) had taken place. After all, Mike hated Windows and had
had nothing but problems with both 95 and NT.
<P>
But the next week when I stopped over, I found my friend was
back to running Windows 95, unhappy as ever about his daily
crashes and computer problems. It is important to understand
that Mike isn't some <EM>luser</EM>; rather, he is a
sophisticated computer professional with substantial computer
knowledge. He has been a consulting parter with me for major
corporations, and has worked on developing a number of expert
systems. He knows his stuff very well. So why, then, did
Mike fail to embrace the Linux alternative?
<P>
<H1><A NAME="SECTION00040000000000000000">
Why Linux Didn't Work</A>
</H1>
<P>
The answer, unfortunately, is one we advocates hear all the
time. The new user of the Linux system finds that the
learning curve is too steep to be manageable. Like many other
people, Mike has a real life - he has a job, a girlfriend,
various projects and hobbies, and he can not spend all his free
time learning a new way of being productive. Moreover, he
can't afford to devote the days or even weeks it might take
him to learn how to administer a system so that he can
accomplish even simple tasks. He needs to be productive
today, and tomorrow, at the same rate he was yesterday.
Because Mike is already familiar with the system and
applications on the windows box, and not with those on Linux,
he could not afford to switch. When the initial learning curve
is so steep getting to be equally productive when moving from
another OS to Linux can be daunting. This is even more true
if one is an expert user on the non-Linux machine.
<P>
<H2><A NAME="SECTION00041000000000000000">
What Learning Curve?</A>
</H2>
<P>
Many <EM>OS Bigots</EM> (myself included on my more polemical days)
will counter that it is simply untrue that it takes that long
to learn a new system. Or we'll simply deny that Linux is
really all that complicated. Instead of recognizing any
validity in the statements made by the complainants, we
attempt to invalidate the complaint by suggesting that the
person in question must be a <EM>luser</EM> instead of a <EM>user</EM>.
``I learned Unix in a couple of hours,'' or ``Heck, just pick
up <U>Unix Unleashed</U> and read it,'' are statements that carry
the implication that the person being addressed is somehow not
as competent as the speaker.
<P>
This approach does more damage to the Linux (and Unix)
community than many people realize. We have good solutions to
many problems, but if we aren't willing to take the people who
need those solutions seriously, we will not be heard.
<P>
<H1><A NAME="SECTION00050000000000000000">
The Problem and Three Solutions:</A>
</H1>
<P>
So, the question arises, ``How do we Linux users, developers,
and advocates help those with limited time for learning new
systems make the switch?'' There are several answers to this
question, but they almost all fall into three categories. I
call these categories the <EM>OS/2 revisited approach</EM>, the
<EM>suck it up approach</EM>, and the <EM>delayed skill
transfer approach</EM>. What are these methods? Glad you asked!
<P>
<H2><A NAME="SECTION00051000000000000000">
Big Blue, Round Two</A>
</H2>
<P>
The first, the <EM>OS/2 revisited approach</EM>, consists of
making windows available on or under the new OS. IBM had
moderate success in getting dissatisfied users to switch to
their products by providing a technically superior system that
managed to provide the user with their favorite windows
applications. Linux has a number of programs and libraries
available that help with this approach. DOSEMU, the TWIN
library, WINE, WABI, and others are all efforts to provide the
user with access to his favorite MS products.
<P>
This approach has some big dividends. The user is able to
transfer many of his or her skills immediately. There is
little trepidation in wondering how to do word processing on
the very same word-processor you've been using for the last 2
years. There is far less worry about being able to get your
work done when you don't have to worry about finding and
learning new applications in order to accomplish your normal
tasks.
<P>
However, this approach does have some problems. Today, the
most obvious is that windows95 apps are not nearly as portable
to Linux emulation as are the older 3.x apps. This means that
many users are not able to bring over their favorite
applications any more. Rather, the user needs to find and
obtain an outdated version of his or her favorite product. The
user then will need to worry about reformatting old data and
projects to use the older program, as well as concerning
themselves with being able to share their data seamlessly with
coworkers.
<P>
Another major drawback with this approach, as IBM found out,
is that the users are not encouraged to explore the power of
the underlying OS. ``A better memory manager for windows'' is
not what Linux is about. It is not what it does best. And,
like OS/2, eventually users who use it for that purpose will
realize that the increased complexity doesn't pay out any real
dividends. The reason OS/2 failed (regardless of what the
various OS/2 pundits say, it is dead) is the same reason these
various projects will never really be the answer to Linux
advocacy. They don't really solve the problem of getting
users up on the new OS. All they do is offer a false sense of
security at a cost of complexity and a lack of compatibility
with state-of-the-art Windows environments (if there is such a
thing.)
<P>
The trend to develop Windows95-like applications such as
StarOffice on Unix platforms seems to be an extension of this
methodology. Instead of embracing the tenants of ``small is
beautiful'' and ``make each program do one thing well,'' these
development efforts are aimed at reproducing the Suite on Unix.
The advantage of this, is, of course, that it is what managers
expect to find on their computers. The disadvantage is that
the ``Office Suite,'' in all it's ugly, bloated, glory is now
nestled into the Unix culture. Most true devotee's of Unix
will likely dismiss these suites as being against the Unix
grain. Still, they present a way to move reluctant Windows95
people into the Unix world.
<P>
<H2><A NAME="SECTION00052000000000000000">
OK, Take A Deep Breath!</A>
</H2>
<P>
The <EM>suck it up approach</EM>, also known as the <EM>sink
or swim</EM> method can and does work. I, for example, simply
reformatted my hard-drive one day, and never looked back.
However, for most people in real-life business environments,
this isn't possible. Unlike most people, I really did have
lots of time to explore my system, and being in graduate
school, I had few applications I really needed to run.
``Mission Critical'' doesn't apply to most people in master's
programs. Like the example of Mike, above, the real user
just doesn't have the time to waste on learning how to be
productive all over again. Still, for some users, it can
work. The key is having good teachers who are also good
system administrators on hand to help the user along. Had I
been willing to visit Mike on a daily basis to hand hold
while he got up to speed, he would probably be running on Red
Hat instead of Redmond.
<P>
The advantage to this method is that it doesn't rely on a
sense of security. Unlike <EM>OS/2 revisited</EM>, the
<EM>suck it up'ers</EM> have to dive into the system, they have
to tackle the learning curve, and with good teachers it can
happen fairly quickly. Most people can learn the basics of
Emacs, LaTeX, Unix shells and command lines, and the various
other Unix tools and tricks in a week or less. While there
may still be some touch and go moments when problems with
system administration raise their ugly head, for the most
part, after some intensive training and a few moments of
butterflies in the stomach, the person can manage to get
along.
<P>
The problem with this approach is, of course, that it takes a
leap of faith, that most people are very leery of making.
And, I might add, they are right to be leery of doing it this
way. Some people simply won't get the new way no matter how
patient you are, because they will be stressing out over some
project that they are working on. Others, because of various
concerns about being able to get the job done, simply won't
leave the tried and true - no matter how obvious it is that
it is really tried and found wanting. Let's face it, most
people are nervous about the unknown, and moving to Linux is
the unknown for someone whose only computer experience is MS
or Mac based. Here again, the aforementioned Office-ish
suites can come in very handy. While rarely the best tool for
any one job, they can be used to make the <EM>suck it up'er</EM>
more comfortable in his or her new environment.
<P>
It is important to realize that there is always the
occasional person whose task still can not be adequately
completed under Linux. There are specialty apps which require
MS or Mac products to run. For these people, leaping before
looking, long and hard, can be disastrous. And, we gurus
need to be aware that one story from such a person on
newsgroups and mailing lists goes as far as ten stories of
positive experiences. Trying to coerce most people into the
<EM>suck it up</EM> method is just asking for trouble. You risk
your credibility about OS matters on your ability to teach and
support someone in learning a new environment. This is a
gamble that most likely won't pay off often enough to be worth
the risk. Our most powerful weapon in the Linux community has
always been our honesty and integrity when it comes to the
products we advocate. To push someone to use a system they
are not ready for can have deleterious effects on that
reputation.
<P>
<H2><A NAME="SECTION00053000000000000000">
Putting one foot in front of the other</A>
</H2>
<P>
This brings us to the last method - the <EM>delayed skill
transfer approach</EM>. What is this? It's simple -- give
Windows, NT and Mac users Unix tools to use on their current
projects! Simple, huh? The problem is, in our zest to push
the Linux point of view on people, we often forget that we can
give some demonstration of the power of the Unix way which is
utterly non-threatening to new users. By replacing the
command windows prompt with bash, by changing dir to ls,
by adding ghostview, ghostscript, emacs, perl, LaTeX and other
tools to the Windows environment, we allow for users to
develop their skills and confidence in Unix methods without
compromising their ability to currently work.
<P>
While this method may take longer to get any particular user
up and running in a completely Linux-only environment, it also
offers the most benefits with the fewest drawbacks. The
benefits of the <EM>OS/2 revisited</EM> method, namely that of
having tools that you are comfortable with, is realized
without the deficit of having to rely on out-dated versions
or be worried about underlying complexities. The drawbacks of
the <EM>suck it up</EM> approach are avoided as the users are
given plenty of time to become familiar with the new tools in
an environment that doesn't endanger any current projects.
Thus the users are less stressed and more open to trying new
things, for the new things don't entail the need to be
concerned about not being able to accomplish critical tasks.
<P>
Further, after a few weeks or months, those ``mission critical''
tasks are now being accomplished on Unix tools that have been
ported to the user's (soon to be formerly) favorite
platform. Thus, when the switch over to Linux comes, the user
no longer has to learn two new things - how to be productive
and how to system manage. Instead, they are instantly
productive and can learn the underlying system at their
leisure. More often than not they will come to want the extra
functionality of things like named pipes, IPC, and other Unix
niceties that are unavailable in their scaled down ports.
<P>
<H1><A NAME="SECTION00060000000000000000">
Why it isn't happening?</A>
</H1>
<P>
While this seems to be a fairly obvious method of helping
users move to Unix environments it seems to be one of the
least attempted. There are a few reasons for this.
<P>
<UL>
<LI>Advocates tend to be very strong in their opinion that
windows=bad, Unix=good. They are not particularly willing to
compromise their ideals for what seems like limited gains.
<LI>Advocates tend towards seeing the computing market as a
battleground of sorts where Unix is pitted against the ``evil
empire.'' Anything that doesn't seem like a direct attack upon
Microsoft can be seen as an act of near treason.
<LI>Linux users tend to spend lots of time under Linux,
they are a bit out of touch with the windows world. As a
result, they may not be aware of that neat new port of Bash as
the command shell under 95, or that perl can run (and do some
neat registry tricks too!)
</UL>
<P>
<H1><A NAME="SECTION00070000000000000000">
Conclusion</A>
</H1>
<P>
The point of all this is that there is more than one way to
skin a cat (or in the case of Gates-ware, a weasel). Linux
advocacy can, and should, take forms that are appropriate to
the particular situation of a particular user. A student in
a computer science program with lots of free-time probably
should opt for the <EM>suck it up</EM> approach. A person with
plenty of support from a local administrator and plenty of
legacy apps might benefit greatly from the <EM>OS/2
revisited method</EM>. And, most importantly, we can't forget that
promoting Unix tools under other OS's is a form of advocacy.
More importantly, in an environment where mission critical
apps and projects abound, it may be the most effective form of
advocacy. Keep up with available ports of your favorite Unix
tools under other systems, and you can increase your
conversion success rate!
<P>
<H1><A NAME="SECTION00080000000000000000">
About this document ... </A>
</H1>
<STRONG>Evangelism: A Unix Bigot and Linux Advocate's Spewings</STRONG><P>
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<A HREF="http://www-dsed.llnl.gov/files/programs/unix/latex2html/manual/"><STRONG>LaTeX</STRONG>2<tt>HTML</tt></A> translator Version 98.1 release (February 19th, 1998)
<P>
Copyright &#169; 1993, 1994, 1995, 1996, 1997,
<A HREF="http://cbl.leeds.ac.uk/nikos/personal.html">Nikos Drakos</A>,
Computer Based Learning Unit, University of Leeds.
<P>
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<STRONG>latex2html</STRONG> <tt>-split 0 lj_advocacy.tex</tt>.
<P>
The translation was initiated by David Wagle on 1998-03-23
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<center><H5>Copyright &copy; 1998, David Wagle <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
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<center>
<H1>A Glimpse of Icon</H1>
<H4>By <a href="mailto:jeffery@cs.utsa.edu">Clinton Jeffery</a>
and <A HREF="mailto:spm@drones.com">Shamim Mohamed</A></H4>
</center>
<P> <HR> <P>
<h3> Motivation </h3>
<P> <HR> <P>
Many languages introduce special capabilities for specific kinds of
applications, but few present us with more powerful control structures or
programming paradigms. You may be comfortable sticking with a language
you already know, but if you are challenged to write complex programs and
are short on time, you need the best language for the job. Icon is a
high-level programming language that looks like many other programming
languages but offers many advanced features that add up to big gains
in productivity. Before we get to all that, let us write the canonical
first program:
<PRE>procedure main()
write(&quot;Hello, world!&quot;)
end</PRE>
If you've installed Linux Icon,
Save this in a file named <code>hello.icn</code> and run <I>icont</I>, the
Icon translator on it:
<PRE>icont hello -x</PRE>
<I> icont</I> performs some syntax checking on <code>hello.icn</code> and
transforms the code into
instructions for the Icon virtual machine, which will be saved in
<code>hello</code>. The <code>-x</code> option tells <code>icont</code> to
execute the program also.
<p>
We are introducing many concepts, so don't expect to understand
everything the first time through -- the only way to learn a language is to
write programs in it; so get Icon, and take it for a test drive.
<h4><u>Genealogy</u></h4>
Despite its name, Icon is not a visual programming language -- its
look-and-feel descends from Pascal and C. The important thing about
Icon is not that its syntax is easy to learn. Icon's semantics, which
generalize ideas from SNOBOL4, succeed in adding
considerable power to the familiar notation found in most
programming languages. This is noteworthy because most languages that add real
power (APL, Lisp, and SmallTalk are examples) do so with a syntax that
is so different that programmers must learn a new way of thinking to use
them. Icon adds power `under the hood' of a notation most programmers are
already comfortable with.<p>
Icon was developed over several years at the University of Arizona by a team
led by Ralph Griswold. Today, it runs on many platforms and is used by
researchers in algorithms, compilers, and linguistics as well as system
administrators and hobbyists. The implementation and source code are
in the public domain.
<P> <HR> <P>
<H3>Variables, Expressions, and Type</H3>
<P> <HR> <P>
Icon's expression syntax starts out much as do most languages.
For example, <code>i+j</code>
represents the arithmetic addition of the values stored in the variables
<code>i</code> and <code>j</code>, <code>f(x)</code> is a call
to <code>f</code> with argument <code>x</code>, variables may be global
or local to a procedure, and so on.
<p>
Variable declarations are not required, and variables can hold any type of
value. However, Icon is a strongly typed language; it knows the type of each
value and it does not allow you to mix invalid types in expressions. The
basic scalar types are integers, real numbers, strings, and sets of
characters (csets). Integers and strings can be arbitrarily large; and
strings can contain any characters. There are also structured types: lists,
associative arrays, sets and records. Icon performs automatic storage
management.
<h4><u>Goal-directed Expression Evaluation</u></h4>
Icon's major innovation is its expression evaluation mechanism. It avoids
certain problems widely found in conventional languages in which each
expression always computes one result. In such languages, if no valid
result is possible, a sentinel value such as -1, NULL, or EOF (end-of-file)
is returned instead. The program must check for such errors using boolean
logic and if-then tests, and the programmer must remember many different
sentinel values used in different circumstances. This is cumbersome.
Alternative ideas such as exceptions have been developed in
some languages, but they introduce complexity and problems of their own.
<h4><u>Success and Failure</u></h4>
In Icon, expressions are <em>goal-directed</em>. When it is evaluated, every
expression has a goal of producing results for the surrounding expression.
If an expression succeeds in producing a result, the surrounding expression
executes as intended, but if an expression cannot produce a result, it is
said to <em>fail</em> and the surrounding expression cannot be performed and
in turn fails. This powerful concept subsumes Boolean logic and the
use of sentinel values, and allows a host of further improvements.
As an example, consider the expression <code>i &gt; 3</code>
-- if the value <code>i</code> is greater than 3 the expression succeeds,
otherwise it fails.
<P>
Control structures such as <code>if</code> check for success, so
<PRE> if i &gt; 3 then ...</PRE> does the expected thing. Since the
expression semantics are not encumbered with the need to propagate
boolean (or 0 and 1) values, comparison operators can instead propagate
a useful value (their right operand), allowing expressions such as
<code>3 &gt; i &gt; 7</code>
which is standard in mathematics, but doesn't work in most languages.
<p>
Since functions that fail do not need to return an error code separately
from the results, detecting cases such as end-of-file is simpler, as in:
<PRE> if line := read() then write(process(line))</PRE>
On end-of-file, <code>read()</code> fails, causing the assignment expression
tested in the if-part to fail. When the test fails, the <i>then</i> branch
is not executed so the call to <code>write()</code> does not occur.
Since failure propagates through an expression, the above example is equivalent
to
<PRE> write(process(read())</PRE>
<h4><u>Generators</u></h4>
Some expressions can naturally produce more than one result. These
expressions are called <em>generators</em>.
Consider the task of searching for a substring within a string, and returning
the position at which the substring occurs, as in Icon's <code>find()</code>
function:
<PRE> find(&quot;or&quot;, &quot;horror&quot;)</PRE>
In conventional languages, this would return one of the possible return
values, usually the first or the last. In Icon, this expression is capable
of returning all the values, depending on the execution context.
If the surrounding expression only needs one value, as in the case of an
<i>if</i> test or an assignment, only the first value of a generator is
produced. If a generator is part of a more complex expression, then
the return values are produced in sequence until the whole expression
produces a value. In the expression
<PRE> find(&quot;or&quot;, &quot;horror&quot;) &gt; 3 </PRE>
the first value produced by <code>find()</code>, a 2, causes the
<code>&gt;</code> operation to fail. Icon <em>resumes</em> the call to find(),
which produces a 4, and the expression succeeds.
<p>
The most obvious generator is the alternation operator |. The expression
<pre> expr</PRE><sub>1</sub> <PRE>| expr</PRE><sub>2</sub>
is a generator that produces its lefthand side followed by its righthand
side, if needed by the surrounding expression. Consider
<code>f(1|2)</code> -- <code>f</code> is first invoked with the value 1;
if that does not produce a value, the generator is resumed for another
result and <code>f</code> will be called again with the value 2.
As another example of the same operator,
<pre> x = (3 | 5)</pre>
is equivalent to but more concise than C's (x == 3) || (x == 5).
When more than
one generator is present in an expression, they are resumed in a LIFO manner.
<pre> (x | y) = (3 | 5)</pre>
is the Icon equivalent of C's
<pre> (x == 3) || (x == 5) || (y == 3) || (y == 5)</pre>
<p>
In addition to <code> | </code>, Icon has a <i>generate</i> operator
<code> ! </code> that generates elements of data structures, and a
generator <code>to</code> that produces ranges of integers. For example,
<code>!L</code> generates the elements of list L, and <code>1 to 10</code>
generates the first ten positive integers.
Besides these operators that generate results, most generators in Icon
take the form of calls to built-in and user-defined procedures.
Procedures are discussed below.
<h4><u>Iteration</u></h4>
Icon has the ordinary <code>while</code> loop where the control expression is
evaluated before each iteration. For generators, an alternative loop is
available
where the loop body executes once per result produced by a single evaluation
of the control expression. The alternative loop uses the reserved word
<code>every</code> and can be used in conjunction with the <code>to</code>
operator to provide the equivalent of a <code>for</code>-loop:
<pre> every i := 1 to 10 do ...</pre>
The point of <code>every</code> and <code>to</code> is not that you can use
them to implement a for-loop; Icon's generator mechanism is quite a
bit more general. The <code>every</code> loop lets you
walk through all the results of a generator giving you iterators
for free. And <code>every</code> isn't limited to sequences of numbers or
traversals of specific data structures like iterators in some languages; it
works on any expression that contains generators.
<pre> every f(1 | 1 | 2 | 3 | 5 | 8)</pre>
executes the function <code>f</code> with the first few
fibonacci numbers, and
the example could be generalized to a user-defined generator procedure
that produced the entire fibonacci sequence.
Using generators requires a bit of practice, but then it is fun!
<P> <HR> <P>
<H3>Procedures</H3>
<P> <HR> <P>
Procedures are a basic building block in most languages, including Icon.
Like C, an Icon program is organized as a collection of procedures and
execution starts from a procedure named <code>main()</code>.
Here is an example of an ordinary procedure. This one generates and sums
the elements of a list <code>L</code>, whose elements had better be numbers
(or convertible to numbers).
<PRE>procedure sum(L)
total := 0
every total +:= !L
return total
end</PRE>
<P>
A user can write her own generator by including a
<pre> suspend <em>expr</em></pre>
in a procedure where a result should be produced. When a procedure
suspends, it transfers a result to the caller, but remains available to
continue where it left off and generate more results. If the expression
from which it is called needs more or different results in order to succeed,
the procedure will be resumed.
The following example generates the elements from parameter <code>L</code>,
but filters out the zeros.
<PRE>procedure nonzero(L)
every i := !L do
if i ~= 0 then suspend i
end</PRE>
The <code>fail</code> expression makes the procedure fail, i.e. causes control
to go back to the calling procedure without returning a value. A procedure
also fails implicitly
if control flows off the end of the procedure's body.
<P> <HR> <P>
<h3> String Processing </h3>
<P><HR> <P>
Besides expression evaluation, Icon offers compelling features to reduce the
effort required to write complex programs. From Icon's ancestor SNOBOL4, the
granddaddy of all string processing languages, Icon inherits some of the
most flexible and readable built-in data structures found in any language.
<h4><u>Strings</u></h4>
Parts of Icon strings are accessed using the subscript operator. Indexes
denote the positions <em>between</em> characters, and pairs of indexes
are used to pick out substrings. If <code>s</code> is the string
<code>&quot;hello, world&quot;</code> then the expressions
<pre> s[7] := &quot; linux &quot;
s[14:19] := &quot;journal&quot;</pre>
change <code>s</code> into <code>&quot;hello, linux journal&quot;</code>,
illustrating
the ease with which insertions and substitutions are made. A myriad of
built-in functions operate on strings; among them are the operators for
concatenation (<code>s1 || s2</code>) and size
(<code>*s</code>).
<H4><u>String Scanning</u></H4>
The string analysis facility of Icon is called <em>scanning</em>. A scanning
environment is set up by the <code>?</code> operator:
<PRE> s ? expr</PRE>
A scanning environment has a
string and a current position in it. <em>Matching functions</em> change this
position, and return the substring between the old and new positions. Here
is a simple example:
<PRE> text ? {
while move(1) do
write(move(1))
}</PRE>
<code>move</code> is a function that advances the position by its argument; so
this code writes out every alternate character of the string in
<code>text</code>. Another matching function is <code>tab</code>, which sets
the position to its argument.
<em>String analysis</em> functions examine a string and generate the
interesting positions in it. We have already seen
<code>find</code>, which looks
for substrings. These functions default their subject to the string being
scanned. Here is a procedure that produces the words from the input:
<PRE>procedure getword()
while line := read() do
line ? while tab(upto(wchar)) do {
word := tab(many(wchar))
suspend word
}
end</PRE>
<code>upto(c)</code> returns the next position of a character from the cset
<code>c</code>; and <code>many(c)</code>
returns the position after a sequence of characters from <code>c</code>.
The expression <code>tab(upto(wchar))</code>
advances the position to a character
from <code>wchar</code>, the set of characters that make up words; then
<code>tab(many(wchar))</code> moves the position to the end of the word and
returns the word that is found.
<P> <HR> <P>
<H3>Regular Expressions</H3>
<P> <HR> <P>
The Icon Program Library (included with the distribution) provides regular
expression matching functions. To use it, include the line
<code>link regexp</code> at the top of the program. Here is an example of
`search-and-replace':
<PRE>procedure re_sub(str, re, repl)
result := &quot;&quot;
str ? {
while j := ReFind(re) do {
result ||:= tab(j) || repl
tab(ReMatch(re))
}
result ||:= tab(0)
}
return result
end</PRE>
<P>
<P> <HR> <P>
<H3>Structures</H3>
<P> <HR> <P>
Icon has several structured (or non-scalar) types as well that help organize
and store collections of arbitrary (and possibly mixed) types of values. A
<em>table</em> is an associative array, where values are stored indexed by
keys which may be of arbitrary type; a list is a group of values accessed
by integer indices as well as stack and queue operations; a set is an
unordered group of values, etc.
<H4><u>Tables</u></H4>
A table is created with the <code>table</code> function. It takes one argument:
the default value, i.e. the value to return when lookup fails. Here is a
code fragment to print a word count of the input (assuming the
<code>getword</code>
function generates words of interest):
<PRE> wordcount := table(0)
every word := getword() do
wordcount[word] +:= 1
every word := key(wordcount) do
write(word, &quot;\t&quot;, wordcount[word])</PRE>
(The <code>key</code> function generates the keys with which values have been
stored.) Since the default value for the table is 0, when a new word is
inserted, the default value gets incremented and the new value (i.e. 1) is
stored with the new word. Tables grow automatically as new elements are
inserted.
<H4><u>Lists</u></H4>
A list can be created by enumerating its members:
<PRE> L := [&quot;linux&quot;, 2.0, &quot;unix&quot;]</PRE>
Lists are dynamic; they grow or shrink through calls to list manipulation
routines like <code>pop()</code> etc. Elements of the list can be obtained either
through list manipulation functions or by subscripting:
<PRE> write(L[3])</PRE>
There is no restriction on the kinds of values
that may be stored in a list.
<H4><u>Records and Sets</u></H4>
A record is like a struct in C, except that there is no restriction
on the types that can be stored in the fields. After a record is declared:
<PRE>record complex(re, im)</pre>
instances of that record are created using a constructor procedure with
the name of the record type, and on such instances, fields are accessed
by name:
<pre> i := complex(0, 0)
j := complex(1, -1)
if a.re = b.re then ...</PRE>
<P>
A set is an unordered collection of values with the uniqueness property
i.e. an element can only be present in a set once.
<PRE> S := set([&quot;rock lobster&quot;, 'B', 52])</PRE>
The functions <code>member</code>, <code>insert</code>, and
<code>delete</code> do what their
names suggest. Set intersection, union and difference are provided by
operators. A set can contain any value (including itself, thereby neatly
sidestepping Russell's paradox!).
<P> <HR> <P>
<H3>Graphs</H3>
<P> <HR> <P>
Since there is no restriction on the types of values in a list, they can be
other lists too. Here's an example
of a how a graph or tree may be implemented with lists:
<PRE>record node(label, links)
...
barney := node(&quot;Barney&quot;, list())
betty := node(&quot;Betty&quot;, list())
bambam := node(&quot;Bam-Bam&quot;, list())
put(bambam.links, barney, betty)</PRE>
<H4><u>An Example</u></H4>
Let us now do a little example to illustrate the above concepts. Here is
a program to read a file, and generate a concordance i.e. for every
word, print a list of the lines it occurs on. We want to skip short words
like `the' though, so we only count the words longer than 3 characters.
<PRE>global wchar
procedure main(args)
wchar := &amp;ucase ++ &amp;lcase
(*args = 1) | stop(&quot;Need a file!&quot;)
f := open(args[1]) | stop(&quot;Couldn't open &quot;, args[1])
wordlist := table()
lineno := 0
while line := read(f) do {
lineno +:= 1
every word := getword(line) do
if *word &gt; 3 then {
# if <em>word</em> isn't in the table, set entry to empty list
/wordlist[word] := list()
put(wordlist[word], lineno)
}
}
L := sort(wordlist)
every l := !L do {
writes(l[1], &quot;\t&quot;)
linelist := &quot;&quot;
# Collect line numbers into a string
every linelist ||:= (!l[2] || &quot;, &quot;)
write(linelist[1:-2])
}
end
procedure getword(s)
s ? while tab(upto(wchar)) do {
word := tab(many(wchar))
suspend word
}
end</PRE>
If we run this program on this input:
<PRE>Sing, Mother, sing.
Can Mother sing?
Mother can sing.
Sing, Mother, sing!</PRE>
the program writes this output:
<PRE>Mother 1, 2, 3, 4
Sing 1, 4
sing 1, 2, 3, 4</PRE>
While we may not have covered all the features used in this program, it
should give you a feeling for the flavour of the language.
<P> <HR> <P>
<H3>Co-expressions</H3>
<P> <HR> <P>
Another novel control facility in Icon is the co-expression, which is an
expression encapsulated in a thread-like execution context where its results
can be picked apart one at a time. Co-expressions are are more portable
and more fine-grained than comparable facilities found in most languages.
Co-expressions let you `capture' generators and then use their results
from multiple places in your code. Co-expressions are created by
<pre> create <i>expr</i></pre>
and each result of the co-expression is requested using the <code>@</code>
operator.
<p>
As a small example, suppose you have a procedure <code>prime()</code> that
generates an infinite sequence of prime numbers, and want to number each
prime as you print them out, one per line. Icon's <code>seq()</code>
function will generate the numbers to precede the primes, but there is no
way to generate elements from the two generators in tandem; no way except
using co-expressions, as in the following:
<pre> numbers := create seq()
primes := create prime()
every write(@numbers, ": ", @primes)
</pre>
More information about co-expressions
can be found at <code> <a href="http://www.drones.com/coexp/">
http://www.drones.com/coexp/</a></code>
and a complete description is in the Icon language book mentioned below.
<P> <HR> <P>
<h3> Graphics </h3>
<P><HR> <P>
Icon features high-level graphics facilities that are portable across
platforms. The most robust implementations are X Window and Microsoft
Windows; Presentation Manager, Macintosh, and Amiga ports are in various
stages of progress. The most important characteristics of
the graphics facilities are:
<ul>
<li> simplicity, ease of learning
<li> windows are integrated with Icon's existing I/O functions
<li> straightforward input event model
</ul>
As a short example, the following program opens a window and allows the user
to type text and draw freehand on it using the left mouse button, until an
ESC char is pressed. Clicking the right button moves the text cursor to a
new location. Mode <code>&quot;g&quot;</code> in the call to open stands
for &quot;graphics&quot;. <code>&amp;window</code> is a special global
variable that serves as a default window for graphics functions.
<code>&amp;lpress</code>, <code>&amp;ldrag</code>, and
<code>&amp;rpress</code> are special constants that denote left mouse button
press and drag, and right mouse button press, respectively.
<code>&amp;x</code> and <code>&amp;y</code> are special global variables
that hold the mouse position associated with the most recent user action
returned by Event(). <code>&quot;\e&quot;</code> is a one-letter Icon
string containing the escape character.
<pre>procedure main()
&amp;window := open(&quot;LJ example&quot;,&quot;g&quot;)
repeat case e := Event() of {
&amp;lpress | &amp;ldrag : DrawPoint(&amp;x,&amp;y)
&amp;rpress : GotoXY(&amp;x,&amp;y)
&quot;\e&quot; : break
default : if type(e)==&quot;string&quot; then writes(&amp;window, e)
}
end
</pre>
A complete description of the graphics facilities is available on the web at
<A href="http://www.cs.arizona.edu/icon/docs/ipd281.html">
<code>http://www.cs.arizona.edu/icon/docs/ipd281.html</code></A>
<P> <HR> <P>
<H3>POSIX Functions</H3>
<P> <HR> <P>
An Icon program that uses the POSIX functions should include the header file
<code>posixdef.icn</code>. On error, the POSIX functions fail and set the
keyword
<code>&amp;errno</code>; the corresponding printable error string is
obtained by
calling <code>sys_errstr()</code>.
<P>
Unix functions that return a C struct (or a list, in Perl) return records
in Icon. The
fields in the return values have names similar to the Unix counterparts:
<I>stat()</I> returns a record with fields <I>ino</I>, <I>
nlink</I>, <I>mode</I> etc.
<P>
A complete description of the POSIX interfaces is included in the
distribution; an HTML version is available on the web, at
<A HREF="http://www.drones.com/unicon/">http://www.drones.com/unicon/</A>.
We look at a few small examples here.
<P> <HR> <P>
<H3>An Implementation of <TT>ls</TT></H3>
<P> <HR> <P>
Let us look at how a simple version of the Unix <TT>ls</TT> command may be
written. What we need to do is to read the directory, and perform a
<TT>stat</TT> call on each name we find. In Icon, opening a directory is
exactly the same as opening a file for reading; every <I>read</I>
returns one filename.
<PRE> f := open(dir) | stop(name, &quot;:&quot;, sys_errstr(&amp;errno))
names := list()
while name := read(f) do
push(names, name)
every name := !sort(names) do
write(format(lstat(name), name, dir))</PRE>
The <I>lstat</I> function returns a record that has all the information
that <TT>lstat(2)</TT> returns. One difference between the Unix version and
the Icon version is
that the <TT>mode</TT> field is
converted to a human readable string -- not an integer on which you
have to do bitwise magic on. (And in Icon, string manipulation is
as natural as a bitwise operation.)
<P>
The function to format the information is simple; it also checks
to see if the name is a symbolic link, in which case it prints the value of
the link also.
<PRE>link printf
procedure format(p, name, dir)
s := sprintf(&quot;%7s %4s %s %3s %8s %8s %8s %s %s&quot;,
p.ino, p.blocks, p.mode, p.nlink,
p.uid, p.gid, p.size, ctime(p.mtime)[5:17], name)
if p.mode[1] == &quot;l&quot; then
s ||:= &quot; -&gt; &quot; || readlink(dir || &quot;/&quot; || name)
return s
end</PRE>
<P> <HR> <P>
<H3>Polymorphism and other pleasant things</H3>
<P> <HR> <P>
It's not just <I>stat</I> that uses human-readable values --
<I>chmod</I> can accept an integer that represents a bit pattern
to set the file mode to, but it also takes a string just like the shell
command:
<PRE> chmod(f, &quot;a+r&quot;)</PRE>
And the first argument: it can be either an opened file or a path to a file.
Since Icon values are typed, the function knows what kind of value it's
dealing with -- no more <TT>fchmod</TT> or <TT>fstat</TT>. The same applies to
other functions -- for example, the Unix functions <TT>getpwnam</TT>,
<TT>getpwuid</TT> and <TT>getpwent</TT> are all subsumed by the Icon function
<I>getpw</I> which does the appropriate thing depending on the type of
the argument:
<PRE> owner := getpw(&quot;ickenham&quot;)
root := getpw(0)
while u := getpw() do ...</PRE>
Similarly, <I>trap</I> and <I>kill</I> can accept a signal number
or name; <I>wait</I> returns human-readable status; <I>chown</I>
takes a username or uid; and <I>select</I> takes a list of files.
<P> <HR> <P>
<H3>Using <code>select</code></H3>
<P><HR> <P>
The <code>select()</code> function waits for input to become
available on a set of
files. Here is an example of the usage -- this program waits for typed
input or for a
window event, with a timeout of 1000 milliseconds:
<P>
<PRE> repeat {
while *(L := select([&amp;input, &amp;window], 1000)) = 0 do
... handle timeout
if &amp;errno ~= 0 then
stop(&quot;Select failed: &quot;, sys_errstr(&amp;errno))
every f := !L do
case f of {
&amp;input : handle_input()
&amp;window : handle_evt()
}
}</PRE>
If called with no timeout value, select will wait forever. A timeout of 0
performs a poll.
<P> <HR> <P>
<H3>Networking</H3>
<P><HR> <P>
Icon provides a much simpler interface to BSD-style sockets.
Instead of the four different system calls that are required to
start a TCP/IP server using Perl, only one is needed in Icon--the
<I>open</I> function opens network connections as well as files. The first
argument to <I>open</I>
is the network address to connect to -- <I>host:port</I> for Internet
domain connections, and a filename for Unix domain sockets.
The second argument specifies the type of connection.
<P>
Here is an Internet domain TCP server listening on port 1888:
<PRE>procedure main()
while f := open(&quot;:1888&quot;, &quot;na&quot;) do
if fork() = 0 then {
service_request(f)
exit()
} else
close(f)
stop(&quot;Open failed: &quot;, sys_errstr(&amp;errno))
end</PRE>
The <I>&quot;na&quot;</I> flags indicate that this is a <em>network
accept</em>. Each call to <code>open</code> waits for a network connection
and then returns a file for that connection.
To connect to this server, the <I>&quot;n&quot;</I> (network connect) flag is
used with <code>open</code>. Here's a function that connects to a
`finger' server:
<PRE>procedure finger(name, host)
static fserv
initial fserv := getserv(&quot;finger&quot;) |
stop(&quot;Couldn't get service: &quot;, sys_errstr(&amp;errno))
f := open(host || &quot;:&quot; || fserv.port, &quot;n&quot;) | fail
write(f, name) | fail
while line := read(f) do
write(line)
end</PRE>
Nice and simple, isn't it? One might even call it Art! On the other hand,
writing socket code in Perl is not much
different from writing it in C, except that you have to perform weird
machinations with <TT>pack</TT>. No more! Eschew obfuscation, do it in Icon.
<H4><u>UDP</u></H4>
UDP networking is similar; using <I>&quot;nu&quot;</I> as the second
argument to <I>open</I>
signifies a UDP connection. A datagram is sent either with <I>write</I>
or <I>send</I>, and is received with <I>receive</I>.
Here is a simple client for the UDP `daytime' service, something like
<TT>rdate(1)</TT>:
<PRE> s := getserv(&quot;daytime&quot;, &quot;udp&quot;)
f := open(host || &quot;:&quot; || s.port, &quot;nu&quot;) |
stop(&quot;Open failed: &quot;, sys_errstr(&amp;errno))
writes(f, &quot; &quot;)
if *select([f], 5000) = 0 then
stop(&quot;Connection timed out.&quot;)
r := receive(f)
write(&quot;Time on &quot;, host, &quot; is &quot;, r.msg)</PRE>
Since UDP is not reliable, the <I>receive</I>
is guarded with <I>select</I> (timeout of 5000 ms), or the program
might hang forever if the reply is lost.
<P>
<P> <HR> <P>
<h3> Icon and other languages </h3>
<P> <HR> <P>
The popular languages Perl and Java have been covered in LJ, and we think
it is worth discussing how Icon stacks up against these dreadnaughts.
<H4><u>Perl and Icon</u></H4>
Perl and Icon are both used for similar purposes. Both
languages offer high-level data structures like lists, associative arrays,
etc. Both make it easy to write short prototypes by not requiring
extensive declarations; and both were intended by their designers to be
`user friendly' i.e. intended to make programming easier for the user
rather than to prove some theoretical point.
<p>
But when it comes to language design, Perl and Icon are not at all
alike. Perl has been designed with very little structure -- or,
as Larry Wall puts it, it's more like a natural language than a programming
language.
Perl looks strange
but underneath the loose syntax its semantics are those of a conventional
imperative language. Icon,
on the other hand, looks more like a conventional imperative language but
has richer semantics.
<h4><u>Advantages of Perl</u></h4>
Perl's pattern matching, while not as general a mechanism as Icon's
string scanning, is more concise for recognizing those patterns that can
be expressed as regular expressions. Perl's syntax looks and feels natural
to long-time die-hard UNIX gurus and system administrators,
who have been using utilities such as <i>sh</i>, <i>sed</i>,
and <i>awk</i>. For
some people, Perl is especially appealing because mastering its idiosyncracies
places one in an elite group.
<H4><u>Some misfeatures of Perl</u></H4>
Let us look at some things that are (in our opinion) undesirable qualities
of Perl. These problems do not negate Perl's ingenious features, they
merely illustrate that Perl is no panacea.
<P>
Namespace confusion: it is a bad idea to allow scalar variables, vector
variables and functions to have the same name. This seems like a useful
thing to do, but it leads to write-only code. We think this is primarily
why it's hard to maintain Perl programs. A couple of things are
beyond belief -- <TT>$foo</TT> and <TT>%foo</TT> are different things, but
the expression <TT>$foo{bar}</TT> actually refers to an element of
<TT>%foo</TT>!
<P>
Parameter passing is a mess. Passing arrays by name is just too confusing!
Even after careful study and substantial practice, we still are not absolutely
certain about how to use <TT>*foo</TT> in Perl. As if to make up for the
difficulty of passing arrays by reference, <em>all</em> scalars are passed by
reference! That's very unaesthetic.
<P>
Why are there no formal parameters? Instead, one has to resort to something
that looks like a function call to declare local variables and assign
<TT>@_</TT> to it.
Allowing the parentheses to be left off subroutine calls is also unfortunate;
it is another `easy to write, hard to read' construct. And the distinction
between built-in functions and user-defined subroutines is ugly.
<P>
Variables like <TT>$`</TT> are a bad idea. We think of special
characters as punctuation, we don't expect them to be (borrowing
Wall's terminology) nouns. And the mnemonics that are required are evidence
that these variables place an additional burden of memorization upon
the programmer. (Quick, if you write Perl programs: What's `<TT>$(</TT>'?)
<P>
The distinction between array and scalar contexts also leads to obfuscated
code. Certainly after you've been writing Perl for a while, you get used to
it (and might even like it), but again, this is just confusing. All the
warnings in the Perl documentation about being certain you are evaluating in
the right context is evidence of this.
<P>
<h4><u>Java and Icon</u></h4>
Java takes the middle road in between C/C++ and the class of `very high level
languages' such as Icon and Perl. Java and Icon use a similar
virtual machine (VM) model. Java's VM is both lower-level and more
machine-independent than the Icon VM, but these are implementation artifacts
and it would be possible to implement Java on the Icon VM or Icon on the
Java VM. <p>
The important differences between Java and Icon are differences of philosophy.
The Java philosophy is that everything is an object, nothing is built-in to
the language, and programmers should learn class libraries for all non-trivial
structures and algorithms. Java's lack of operator overloading means that
its object-oriented notation allows no &quot;shorthand&quot; as does C++.
Java's
simplicity is a welcome relief after C++, but its expressive power is so
weak compared to Icon (and several other very high level languages) that
it is hard to argue that Java can supplant these languages. Most of Java's
market share is being carved out of the C and C++ industries.
<h4><u>How to Improve Java</u></h4>
Java has few bad mistakes. The Sumatra Project has itemized some of them in
The Java Hall of Shame at
<code>http://www.cs.arizona.edu/sumatra/hallofshame/</code>.
Most of Java's misfeatures are sins of omission, because the
language designers were trying to be elegant and minimal. We would
like to see a Java dialect with features such as Icon's goal-directed
evaluation, Perl's pattern matching, and APL's array-at-a-time numeric
operators; a description of such a dialect is at
<A HREF="http://segfault.cs.utsa.edu/godiva/">
http://segfault.cs.utsa.edu/godiva/</A>.
<P> <HR> <P>
<h3> Getting Icon </h3>
<P><HR> <P>
<p> Users who become serious
about the language will want a copy of `The Icon Programming Language', by
Ralph and Madge Griswold, Peer-to-Peer Communications 1997,
ISBN 1-57398-001-3.
<p>
Lots of documentation for Icon is available from the University of Arizona, at
<A HREF="http://www.cs.arizona.edu/icon/">http://www.cs.arizona.edu/icon/</A>
There is also a newsgroup on Usenet: comp.lang.icon.
<p>
The Icon source distribution is at:<br>
<A HREF="ftp://ftp.cs.arizona.edu/icon/packages/unix/unix.tgz">ftp://ftp.cs.arizona.edu/icon/packages/unix/unix.tgz</A><br>
The POSIX functions are in the following patch that you need to apply
if you wish to build from sources:
<br>
<A HREF="ftp://ftp.drones.com/unicon-patches.tar.gz">ftp://ftp.drones.com/unicon-patches.tar.gz</A>
<P>
Linux binaries (kernel 2.0 ELF, libgdbm 2.0.0, libX11 6.0, libdl 1.7.14,
libm 5.0.0 and libc 5.2.18)
for Icon (with X11 and POSIX support) are available at
<P>
<table>
<tr><td>
<A HREF="ftp://ftp.drones.com/icon-9.3-3.i386.rpm">ftp://ftp.drones.com/icon-9.3-3.i386.rpm</A> </td><td> Icon
</td></tr><tr><td>
<a HREF="ftp://ftp.drones.com/icon-ipl-9.3-3.i386.rpm">ftp://ftp.drones.com/icon-ipl-9.3-3.i386.rpm</A></td><td> Icon Program Library
</td></tr><tr><td>
<a HREF="ftp://ftp.drones.com/icon-idol-9.3-3.i386.rpm">ftp://ftp.drones.com/icon-idol-9.3-3.i386.rpm</A></td><td> Idol: Object-oriented Icon
</td></tr><tr><td>
<a HREF="ftp://ftp.drones.com/icon-vib-9.3-3.i386.rpm">ftp://ftp.drones.com/icon-vib-9.3-3.i386.rpm</A></td><td> VIB: The Visual Interface Builder
</td></tr><tr><td>
<a HREF="ftp://ftp.drones.com/icon-docs-9.3-3.i386.rpm">ftp://ftp.drones.com/icon-docs-9.3-3.i386.rpm</A></td><td> Documentation
</td></tr>
</table>
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, Clinton Jeffery and Shamim Mohamed<BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
<!--===================================================================-->
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<H4>
"Linux Gazette...<I>making Linux just a little more fun!</I>"
</H4>
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<TD VALIGN=TOP><B><FONT SIZE=+1>muse:</FONT></B>&nbsp;
<OL>
<LI>
<I>v;</I> to become absorbed in thought&nbsp;</LI>
<LI>
<I>n;</I> [ fr. Any of the nine sister goddesses of learning and the arts
in Greek Mythology ]: a source of inspiration&nbsp;</LI>
</OL>
&nbsp;<IMG SRC="../gx/hammel/w.gif" ALT="W" HEIGHT=28 WIDTH=36 ALIGN=BOTTOM>elcome
to the Graphics Muse! Why a "muse"? Well, except for the sisters aspect,
the above definitions are pretty much the way I'd describe my own interest
in computer graphics: it keeps me deep in thought and it is a daily source
of inspiration.&nbsp;
<CENTER><FONT SIZE=-1>[<A HREF="#mews">Graphics Mews</A>][<A HREF="#webwonderings">WebWonderings</A>][<A HREF="#musings">Musings</A>]
[<A HREF="#resources">Resources</A>]</FONT></CENTER>
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&nbsp;
<BR><IMG SRC="../gx/hammel/t.gif" ALT="T" HEIGHT=28 WIDTH=26 ALIGN=LEFT>his column
is dedicated to the use, creation, distribution, and discussion of computer
graphics tools for Linux systems.
<BR>&nbsp;
<BR>Last month's comment on GGI, made mostly as a passing remark, generated
quite a bit of email.&nbsp; A few were very nice letters explaining where
I was mistaken in my perception of GGI.&nbsp;&nbsp; I now have to admit
that I was wrong about what GGI is with respect to X.&nbsp; It does not
try to replace X and for that I'm grateful.&nbsp; But even after getting
numerous emails on the subject from GGI developers and supporters and reading
all the material at the GGI site (plus discussion on various forums including
<A HREF="http://slashdot.org">slashdot.org</A>), I'm still not convinced
GGI is the right thing to do.&nbsp; Call it a gut feeling.
<P>I also got not just a few letters that were a little less than friendly.&nbsp;
So to them, I'll put it plainly - convince the commercial X server vendors
GGI is a good idea and I'll believe it.&nbsp; I trust them.&nbsp; That
said, I should also point out that as a reader of this column you should
make your own decisions.&nbsp; Go to the <A HREF="http://www.ggi-project.org/">GGI
Web site</A> and read their material.&nbsp; Don't trust it simply because
you read it here.&nbsp; Writers make mistakes too.&nbsp; The web makes
it very easy to distribute information, but there are very few checks in
place to force writers to be accurate.&nbsp; The morale:&nbsp; verify your
information with more than one source.
<P>One other thing:&nbsp; one responder very politely suggested that I
should know more about what I write before distributing it in a place that
carries such "authority" - the Linux Gazette.&nbsp; He is correct:&nbsp;
I need to try to be as accurate as possible.&nbsp; But to those who were
not so polite, try to remember:&nbsp; this is just a hobby.&nbsp; I'm not
really a graphics expert and I do get things wrong.&nbsp; If you're going
to nudge me in the right direction, please do so politely.&nbsp; And please,
no more email on GGI.&nbsp; The kernel team is better qualified to decide
GGI's fate in Linux than I.&nbsp; I'm not even certain any of the kernel
developers read this column!
<BR>&nbsp;
<BR>Ok, on to the work at hand.&nbsp; This month I conclude the two part
status update on X servers with information on Metro Link.&nbsp; Last month,
if you recall, I covered XFree86/S.u.S.E and Xi Graphics.&nbsp; Also in
this months issue of the Muse is a little bit of information I gathered
while trying to find some decent offline storage media.&nbsp; I'll kill
the ending - I ended up with an Iomega Jaz drive.&nbsp; But you'll still
want to read about why I chose it and what it takes to install the beast.
<P>Finally, I do a little review of XFPovray.&nbsp; This is an XForms based
front end to POV-Ray, the 3D raytracing engine.&nbsp; I used it recently
in working on another cover for the Linux Journal.
<P>Enjoy!
<P><A NAME="mews"></A>
<BR>&nbsp;
<TABLE BORDER=0 COLS=1 WIDTH="100%" >
<TR>
<TD><IMG SRC="../gx/hammel/mews.gif" ALT="Graphics Mews" HEIGHT=53 WIDTH=242 ALIGN=LEFT></TD>
</TR>
</TABLE>
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Disclaimer: Before I get too far into this
I should note that any of the news items I post in this section are just
that - news. Either I happened to run across them via some mailing list
I was on, via some Usenet newsgroup, or via email from someone. I'm not
necessarily endorsing these products (some of which may be commercial),
I'm just letting you know I'd heard about them in the past month.
<BR>&nbsp;
<TABLE BORDER=0 COLS=3 WIDTH="100%" >
<TR>
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<TD></TD>
</TR>
<TR>
<TD WIDTH="50%">
<H2>
XFree86 3.3.2 is released</H2>
XFree86 version 3.3.2 is now available.&nbsp; The XFree86 3.3 distribution
is available in both source and binary form.&nbsp; Binary distributions
are currently available for FreeBSD (2.2.2+ and 3.0-CURRENT), NetBSD (1.2
and 1.3), OpenBSD, Interactive Unix, Linux (ix86 and AXP), SVR4.0, UnixWare,
OS/2, Solaris 2.6 and LynxOS AT.&nbsp;
<P>The XFree86 documentation is available on-line on their Web server.&nbsp;
The documentation for 3.3 can be accessed at <A HREF="http://WWW.XFree86.org/3.3/">http://WWW.XFree86.org/3.3/</A>.&nbsp;
<P>The XFree86 FAQ is at <A HREF="http://WWW.XFree86.org/FAQ/">http://WWW.XFree86.org/FAQ/</A>.&nbsp;
<P>The XFree86 Web site is at <A HREF="http://WWW.XFree86.org/'">http://WWW.XFree86.org</A></TD>
<TD ROWSPAN="3" WIDTH="2" BGCOLOR="#000000"><IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" HSPACE=1 HEIGHT=1 WIDTH=1></TD>
<TD WIDTH="49%">
<H2>
Moonlight Creator - 3D modeller</H2>
There's a relatively new GPL modeller available. It's call moonlight creator
and can be found at <A HREF="http://www.cybersociety.com/moonlight/">http://www.cybersociety.com/moonlight/</A>&nbsp;
<P>This modeller generated almost as much email as my comment on GGI -
and I didn't even say anything about it last month!&nbsp;
<P>
<HR WIDTH="100%">
<H2>
Pad++</H2>
The NYU Center for Advanced Technology has released a new drawing tool
with some object placement and scaling features possibly worthy of attention
as they continue to extend The Gimp.&nbsp;
<P>Precompiled binaries for several flavors of UNIX.&nbsp;
<BR><A HREF="http://www.mrl.nyu.edu/">http://www.mrl.nyu.edu/</A>&nbsp;
<P>Click on Pad++.&nbsp;
<BR>&nbsp;</TD>
</TR>
<TR>
<TD BGCOLOR="#000000"><IMG SRC="../gx/hammel/cleardot.gif" HSPACE=1 HEIGHT=1 WIDTH=1></TD>
<TD BGCOLOR="#000000"><IMG SRC="../gx/hammel/cleardot.gif" HSPACE=1 HEIGHT=1 WIDTH=1></TD>
</TR>
<TR>
<TD>
<H2>
LParser Source Code Released</H2>
Laurens Lapr&eacute; has released the source code for his popular LParser
tool.&nbsp; LParser creates 3D forms using a descriptive language called
an L-System.&nbsp; It can be used to produce 3D trees, plants and other
organic items.&nbsp; Output formats include VRML, POV-Ray, and DXF.&nbsp;
<P>On his web page Larens writes:&nbsp;
<UL>Source code of the lparser ZIP file (18Kb) can also be downloaded,
for those who want to port or just play with new options. The code is straight,
no frills ANSI-C with even less documentation but it should run on pretty
much anything with a C or C++ compiler. My current job will leave me with
neither the time nor the inclination to do serious code hacking so I'm
throwing the code into the wind, hoping that it will germinate and produce
lots of mutated offspring ! The Lparser source may be freely distributed.</UL>
The Web page for the LParser tool is at <A HREF="http://www.xs4all.nl/~ljlapre/">http://www.xs4all.nl/~ljlapre/.</A></TD>
<TD>
<H2>
SART - 3D Rendering Library for Guile</H2>
SART is a 3D rendering library for Guile. It supports zbuffering, raytracing
and radiosity, with advanced textures, and image processing and other features.
This is the first public release announcement, as the 0.5a2 version is
in the developers opinion sufficiently stable and simple enough to compile
to meet a wider circle of developers (and even users).&nbsp;
<P>SART is freely distributable under GPL. To read more, visit the webpage:&nbsp;
<P><A HREF="http://petra.zesoi.fer.hr/~silovic/sart">http://petra.zesoi.fer.hr/~silovic/sart</A>&nbsp;
<P>The develper asks:&nbsp;
<UL>Now would somebody help me interface this thing with script-fu and/or
guile-gtk?</UL>
</TD>
</TR>
<TR>
<TD COLSPAN="3" WIDTH="100%" BGCOLOR="#000000"><IMG SRC="../gx/hammel/cleardot.gif" HSPACE=1 HEIGHT=1 WIDTH=1></TD>
</TR>
</TABLE>
<H2>
BMRT 2.3.6 Announcment:</H2>
Larry Gritz sent out this announcement this past month:
<UL>Hello, and thanks to everybody for putting up with my extended Beta
period.&nbsp; They say each new group of users discovers a new class of
bugs.&nbsp; Indeed, with the BMRT port for Windows and the nice RIB support
of Rhino (www.rhino3d.com), lots of difficulties with trimmed NURBS came
to the surface and were subsequently fixed.&nbsp; Thanks to those who stuck
it out with me.
<P>BMRT 2.3.6 is finally officially shipping.&nbsp; Er, well, you know
what I mean -- it's on the <A HREF="http://www.seas.gwu.edu/student/gritz/bmrt.html">FTP
site</A>.
<P>Please get the latest and replace the beta, if you had it.&nbsp; I managed
to squash many bugs in the beta, and also reduced both time and memory
by about 15% for large scenes!
<P>Other News: Tony Apodaca and I are co-organizing a course for this summer's
Siggraph conference.&nbsp; The course is titled "Advanced RenderMan: Beyond
the Companion", and will taught by myself and Tony, Ronen Barzel (Pixar),
Clint Hanson (Sony Imageworks), Antoine Durr (Blue Sky|VIFX), and Scott
Johnston (Fleeting Image Animation).
<BR>Hope to see some of you there!
<P>Enjoy the software,
<P>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; -- lg
<BR>&nbsp;</UL>
<HR WIDTH="100%">
<P>&nbsp;<!--
-- Did You Know Section
-->
<H4>
Did You Know?</H4>
...that the Linux Focus online magazine has articles on OpenGL, GLUT, hardware
acceleration issues, and POV-Ray?&nbsp; Take a look at <A HREF="http://mercury.chem.pitt.edu/~angel/LinuxFocus/">http://mercury.chem.pitt.edu/~angel/LinuxFocus/</A>
in issues #2 and #3 (that latter is the current issue).
<BR>&nbsp;
<BR>...there is an article on the future of VRML on the C|Net News Web
site:
<UL><B>VRML spec to drive 3D on Net</B>
<BR>By Erich Luening
<BR>Staff Writer, CNET NEWS.COM
<P><A HREF="http://www.news.com/News/Item/0,4,19992,00.html">http://www.news.com/News/Item/0,4,19992,00.html</A></UL>
...there is a Java based modeller that works under Netscape's Java environment?&nbsp;
Take a look at <B><FONT COLOR="#CC6600">Mondfarilo: the Java Applet</FONT></B>
at <A HREF="http://userpages.itis.com/philip/applet.html">http://userpages.itis.com/philip/applet.html.</A>&nbsp;
The modeller includes support for blobs and lathe objects and can produce
the model information as POV-Ray 3.0 source (although it only does it to
a window - you have to use cut and paste to save it to a file).&nbsp; the
<P>...a description of the Kodak DC120 .KDC File Format can be found at
<A HREF="http://www.hamrick.com/dc120/">http://www.hamrick.com/dc120/</A>.&nbsp;
This format is the one used by the popular Kodak DC120 digital camera.&nbsp;
There is Windows command line source there for converting the files to
JPEG or BMP formats.&nbsp; Anyone looking for a project might look into
porting this to Linux for use with, for example, NetPBM, ImageMagick, or
the GIMP.
<P>...and speaking of digital cameras, did you know there is a small software
package called PhotoPC for Linux that supports a number of digital cameras,
including:&nbsp; Agfa, Epson PhotoPC models, Olympus Digital cameras line,
Sanyo, and Sierra Imaging.&nbsp; Take a look at the PhotoPC Web page at
<A HREF="http://www.average.org/digicam/">http://www.average.org/digicam/</A>.
<P>...there is a good <A HREF="http://triton.slashdot.org/slashdot.cgi?mode=article&artnum=721">editorial
on the future of games</A> on Linux at <A HREF="http://slashdot.org">Slashdot.org</A>.&nbsp;
The editorial was written by <A HREF="mailto:rhuffstedtler@InPhact.com">Rob
Huffstedtler</A>.&nbsp; Its a good piece, and I have to say I agree with
Rob's sentiments about commercial software - it isn't evil and shouldn't
be viewed that way.&nbsp; Any development on Linux - free or commercial
- helps spread the word.&nbsp; Linux isn't just about free software.&nbsp;
Its about having a choice, whether you are a developer or a user.
<P>...the address for the AMAPI modeller has changed (I don't know how
long ago this happened, but I was just notified by a reader):
<UL><A HREF="ftp://sunsite.unc.edu/pub/Linux/apps/graphics/modeling/amapi.linux-elf.us.tar.gz">ftp://sunsite.unc.edu/pub/Linux/apps/graphics/modeling/amapi.linux-elf.us.tar.gz</A>
<BR>or
<BR><A HREF="http://sunsite.unc.edu/pub/Linux/apps/graphics/modeling/amapi.linux-elf.us.tar.gz">http://sunsite.unc.edu/pub/Linux/apps/graphics/modeling/amapi.linux-elf.us.tar.gz</A></UL>
...there is a very good article on the future of 3D gaming on Linux, including
an interview with Dave Taylor, at <A HREF="http://www.planetquake.com/articles/linux.shtm">PlanetQuake</A>.
<BR><!--
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<H2>
Reader Mail</H2>
Nick Cali (<A HREF="mailto:Mktnc@aol.com">Mktnc@aol.com</A>) wrote:
<UL>Just want to drop a line thanking you for your effort at the Gazette
and with Linux.&nbsp; Really, thanks a lot.</UL>
<B><I><FONT COLOR="#993300">'Muse:</FONT></I></B>&nbsp; You're quite welcome.&nbsp;
I had gotten some rather harsh email from someone recently that had me
considering dropping out of the Linux world altogether.&nbsp; Getting little
notes like this, however, helps keep me going.&nbsp; Thanks!
<P>Tristan Savatier (<A HREF="mailto:tristan@mpegtv.com">tristan@mpegtv.com</A>)
wrote:
<UL>In Issue 26 of the Linux Gazette (<A HREF="http://www.ssc.com/lg/issue26/gm.html">http://www.ssc.com/lg/issue26/gm.html</A>)
the link:
<UL>Linux Multimedia Page&nbsp; -> <A HREF="http://www.digiserve.com/ar/linux-snd/">http://www.digiserve.com/ar/linux-snd/</A></UL>
should be renamed: Linux MIDI and Sound Page.</UL>
<B><I><FONT COLOR="#993300">'Muse:</FONT></I></B>&nbsp; Although it is
too late to change it in that issue, I'll make a note of it in the next
issue.&nbsp; Many thanks for the update
<P>Glenn McCarter &lt;<A HREF="mailto:gmccarter@hotmail.com">gmccarter@hotmail.com</A>>
wrote to the IRTC Discussion List:
<UL>I have uploaded a POV-Ray include file "stereo.inc" to my website.&nbsp;
It can produce a stereoscopic view of any POV-Ray scene.&nbsp; This was
the technique I used in my current IRTC entry, "Dawn Patrol".&nbsp; The
url is http://www.geocities.com/SoHo/Gallery/2006/include.htm.&nbsp; Feel
free to download and experiment.&nbsp; Non POV-Ray users: you can also
take a look at the text file to&nbsp; understand the approach involved.&nbsp;
Any raytracing program should be able to utilize this technique.&nbsp;
Feedback and comments welcomed.</UL>
<B><I><FONT COLOR="#993300">'Muse:</FONT></I></B>&nbsp; If anyone takes
a look at this and wants to offer some commets, feel free to drop me a
line.&nbsp; Keep in mind that Glenn may or may not be a Linux/Unix person.&nbsp;
You should keep that in mind if you contact him.
<P>David R. Heys originally asked the GIMP Discussion List (or possibly
the IRTC-L list, I think I may have logged this incorrectly):
<UL>It's been more years than I can count since I've been in school learning
the various formulae for calculating waves, points within objects, distances,
etc. As well, all those old school books are long gone.&nbsp; Can anyone
recommend a good, comprehensive book? I'm looking for something that will
summarize the theories and formulae and present it in layman's terms, or
as close to layman's terms as possible.</UL>
Jerry Anning &lt;<A HREF="mailto:clem@dhol.com">clem@dhol.com</A>> replied:
<UL>The <B><I><FONT COLOR="#006600">Schaum's Outline</FONT><FONT COLOR="#FFCC33">
</FONT></I></B>series of books, published by McGraw-Hill, are mostly good
no-nonsense material.&nbsp; Some of them move a little fast if you are
learning the material for the first time, but they are excellent for reference
and refresher.&nbsp; If you have a little "mathematical maturity" and take
the time to work the problems, you can learn the basics of new subjects
with them as well.&nbsp; The most info-rich ones from a ray tracing perspective
are probably <B><I><FONT COLOR="#006600">Analytic Plane and Solid Geometry</FONT></I></B>,
<B><I><FONT COLOR="#006600">Trigonometry</FONT></I></B>, <B><I><FONT COLOR="#006600">Matrices</FONT></I></B>,
and <B><I><FONT COLOR="#006600">Mathematical Handbook.&nbsp; Descriptive
Geometry</FONT></I></B> and <B><I><FONT COLOR="#006600">Projective Geometry</FONT></I></B>
have their uses, too.&nbsp; For rendering specific math, the standard book
is <B><I><FONT COLOR="#006600">Computer Graphics Principles and Practice</FONT></I></B>
by Foley, vanDam, et al.&nbsp; Here you can learn about splines, antialiasing
theory and many other useful things.&nbsp; I also suggest that you visit
the nearest vocational college bookstore and look for books on shop trigonometry,
particularly compound angles.&nbsp; Standard math books give this material
very short shrift at best.&nbsp; To design things like polyhedra and complex
csg's compound angles are very useful.&nbsp; If you find a used copy of
Bowditch, or some other navigation manual, you can learn a few useful things
about sections of spheres as well.&nbsp; Good luck.</UL>
'<B><I><FONT COLOR="#993300">Muse:</FONT></I></B>&nbsp; I thought this
information might be of general interest to my readers.&nbsp; I know this
is a question I've been asked a few times in the past, but didn't have
quite as complete an answer.&nbsp; By the way, for those that don't know,
CSG is constructive solid geometry - the joining of simple shapes to make
more complex ones.
<P>David Robertson &lt;saga@cs.otago.ac.nz> from the Computer Science Department
of the University of Otaga wrote:
<UL>I enjoyed your summary of X Windows hardware support (or lack thereof).&nbsp;
There is a very interesting web page at
<UL><A HREF="http://parallel.nas.nasa.gov/Parallel/Projects/FOGL/index.html">http://parallel.nas.nasa.gov/Parallel/Projects/FOGL/index.html</A></UL>
which gives NASA Ames position regarding Mesa hardware support.&nbsp; Sadly
the page has not been updated since last October, despite the date at the
bottom of the page.</UL>
<B><I><FONT COLOR="#993300">'Muse:</FONT></I></B>&nbsp; Thanks for the
info Dave.&nbsp; If any of my readers missed it, the first part of the
X Servers Update was in <A HREF="http://www.graphics-muse.org/muse/mar98/gm.html">last
month's issue of the Muse</A>.&nbsp; This month I conclude the report with
information on <A HREF="#xserver">Metro Link</A>.
<P>Alejandro &lt;Cmm.compu@lanet.losandes.com.ar> wrote:
<UL>I read your four article in Linux Journal, now I'm trying to update
my version of gimp. I download a file in rpm format, but it doesn't&nbsp;
work. Could you please tell me where to find the las versions of Gimp,
and what file I should download?</UL>
<B><I><FONT COLOR="#993300">'Muse:</FONT></I></B>&nbsp; www.gimp.org will
point you to the latest versions of both the GIMP and&nbsp; GTK.&nbsp;
If you have updated GTK recently, then you need to update GIMP.&nbsp; Also,
if you've updated the GIMP, you'll need updated GTK libraries.&nbsp; The
two are tied together pretty closely right now since both are getting ready
to go to their respective 1.0 releases.
<P>You're problem, assuming the file you downloaded was a newer version
of the GIMP than what you already had on your system, is probably that
the version of GIMP you downloaded doesn't work with the GTK libraries
you have.&nbsp; In that case, you need to get a compatible version of the
GTK libraries.
<P>Larry S. Marso (larry@marso.com) wrote to the GIMP User list:
<UL>The manual says that Wacom's Artpad is supported, but that patches
are required to take advantage of some features, including the pressure
sensitive pen.&nbsp; (The ArtzII is the 6x8 tablet version).
<P>Where are such patches?</UL>
Dmitry Yaitskov replied:
<UL>If you haven't found them yet, take a look at:&nbsp; http://www.msc.cornell.edu/~otaylor/gtk-gimp/step-by-step.html
<P>But I had some problems with pressure sensitivity, like random pointer
lockups and such, and generally did not like the feel of that much, so
although I still use the patched version of gimp -.99.18 - I turned pressure
sensitivity off.. I have ArtPad II.</UL>
And to this, Larry S. Marso added:
<UL>I should mention that I've found the patched 0.99.18 for Wacom ArtZII
absolutely flawless (including the pressure sensitivity feature).
<P>Well, I wish it was faster ... and had more options.&nbsp; But I've
never experienced "pointer lockups and such".&nbsp; The gsumi app available
on the same web site provides a bitmap drawing capability at extremely
high resolution (the default is 4000x4000) with pressure sensitive drawing
(including caligraphic tips).&nbsp; Great for creating postscript signatures,
and also for high resolution drawings suitable for subsequent manipulation
by Gimp.</UL>
&nbsp;
<P>
<HR WIDTH="100%">
<BR><A NAME="webwonderings"></A>
<BR><IMG SRC="../gx/hammel/webwonderings.jpg" HEIGHT=57 WIDTH=246>
<BR>No time for Web Wonderings this month.&nbsp; I'll try to come up with
something for next month.
<BR>
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<P><A NAME="musings"></A>
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<H2>
&nbsp;Offline storage using a Jaz Drive</H2>
&nbsp;In playing with all the graphics software I've talked about in this
column over the past year, I've managed to fill up the relatively modest
4Gig of disk space I have in the two systems currently running in my home.&nbsp;
When I finish with a project I generally don't need to keep all the work
files on my main hard disks.&nbsp; I also don't want to get rid of them
- they may have something I can use in a later project.&nbsp; So I need
some form of offline storage.
<P>Last year I attempted to address the problem by installing a 450Mb floppy
tape drive on my file server.&nbsp; Once installed, this worked fairly
well with the <A HREF="http://www-math.math.rwth-aachen.de/~LBFM/claus/ftape/">zftape
driver</A> and the <A HREF="http://www.multiline.com.au/~yusuf/">taper</A>
backup software, but initially I had quite a time getting the zftape driver
installed.&nbsp; From the point of view of cost the floppy tape drive is
a good solid solution.&nbsp; A floppy tape drive currently runs less than
$150US.&nbsp; From the point of view of convenience, well, it takes a long
time to backup 1G of data onto a tape drive running off of a floppy controller.&nbsp;
Taper does provide a fairly convenient curses based interface for selecting
the files to be backed up or retrieved, but my needs were less administrative.&nbsp;&nbsp;
I simply wanted to copy over a directory tree to some offline media and
then clean up that tree.&nbsp; Later, if I needed them, I wanted to be
able to copy them back in.&nbsp; I'm wasn't quite at the point where offline
media management was a real problem - I didn't need special tools for keeping
track of what I had on the offline media.&nbsp; What I needed was a removable
hard disk.
<P>Fast forward to this year.&nbsp; Technology once again has heard the
cry of the meek and a flurry of removable hard disk solutions are now hitting
the shelves.&nbsp; One of the first, and currently the most popular if
you believe the noise in the trade magazines, is the <B><FONT COLOR="#CC6600">Iomega
Zip drive</FONT></B>.&nbsp; This is a drive with a cartridge that looks
somewhat like a fat floppy disk.&nbsp; The cartridge holds 100Mb of data,
good enough for 3 or 4 of my smaller projects or one large project.&nbsp;
The drives are running under $130US (I've seen them as low as $119) and
the cartridges are about $20 each, cheaper if bought in bundles of 3 or
more.&nbsp; The drives are available as either parallel or SCSI connected
devices.
<P>The problem with this solution is simply size.&nbsp; 100Mb of data can
be generated fairly fast using the GIMP - I've had swap files from this
tool larger than that.&nbsp; I also had a hard time finding an external
drive.&nbsp; Most of the drives I could find locally were internal drives.&nbsp;
This was probably just a local distribution or supply problem, but then
I didn't look very hard for these drives once I'd decided they simply were
too small.
<P>The next step up from this for Iomega is the <B><FONT COLOR="#CC6600">Jaz</FONT></B>
drive.&nbsp; The first versions of these drives, which is what I purchased,
hold about 1G of data.&nbsp; The latest versions will support the old 1G
cartridges and the newer 2G cartridges.&nbsp; An external SCSI version
is available so I was able to connect the drive to my recently purchased
Adaptec 2940 (which is what I hooked my scanner to) without having to dig
into the innards of my hardware.&nbsp; Again, convenience is a key here
- I was willing to pay a little more for ease of use.
<P>There are a number of removable hard drive solutions on the market today,
however I wasn't able to find information on support for any of these devices
except the Iomega drives.&nbsp; This information is available at the <A HREF="http://www.cnct.com/~bwillmot/jaztool/">Jaztool
</A>page.&nbsp; Jaztool is a package for managing the drive, which I'll
discuss in a moment.&nbsp; Strangely, the Jaz Drive Mini-Howto does not
appear to be on the <A HREF="http://www.linuxresources.com/LDP/index.html">Linux
Documentation Project </A>pages, although a Mini-Howto for the Zip drive
can be found there.
<P>Since the drive is connected to a SCSI controller there aren't any Jaz-specific
drivers necessary.&nbsp; You just need to find a SCSI card with supported
drivers.&nbsp; I chose the Adaptec 2940 because the driver for it (aic7xxx)
was a loadable module that was precompiled in the Red Hat 4.2 distribution
that I currently use.&nbsp; In other words, I was able to simply plug the
card in, run <B><FONT SIZE=-1>insmod aic7xxx</FONT><FONT SIZE=-2>,</FONT></B>
and the card was running.&nbsp; The 2940 has a high density SCSI connector
which is the same sort of connector used by the Jaz drive.&nbsp; I had
previously purchased a high density to 25 pin cable converter to connect
my 2940 to the UMAX scanner (which has the 25pin connector), so I simply
stuck the Jaz driver between the scanner and the adapter.&nbsp; The Jaz
drive comes with a converter, if you need it (the UMAX scanner did not).&nbsp;
Total time for hardware install - about 20 minutes.
<BR>&nbsp;
<BR>As mentioned earlier, there is a tool for managing the Jaz drive called
Jaztool.&nbsp; This package provides a software means to eject, write protect
or read/write enable, and retrieve drive status.&nbsp; Password protection
is available but not officially supported. The man page gives information
on how to use this feature if you wish to give it a try.&nbsp; <I>Mode
5</I> (password protected write <I>and</I> read) is not supported by jaztool,
even though the Jaz drive supports it.&nbsp;&nbsp; You cannot access the
cartridge that comes with the drive in write mode, so you'll need to use
the jaztool program to allow you write access to that cartridge.&nbsp;
The Jaz Drive Mini-Howto explains how to do this quite clearly.&nbsp; The
disk can be mounted as delivered using the VFAT filesystem type, which
means that long file names can be used.&nbsp; This removes the need to
reformat disk with native Unix filesystem.&nbsp; However, the disk that
comes packaged with drive is nearly full.&nbsp; It contains a large number
of MS-related tools for DOS, Win3.1, Win95 and WinNT.&nbsp; Since I didn't
need these I simply mounted the drive and used <B><FONT SIZE=-1>rm -rf
*</FONT></B> on it to clean it up.&nbsp; Once I'd done that, I decided
to go ahead and just place an ext2 filesystem on the driver.&nbsp; This
is simple enough following the information provided in the Jaz Driver Mini-Howto
on the Jaztools page at <A HREF="http://www.cnct.com/~bwillmot/jaztool/">http://www.cnct.com/~bwillmot/jaztool/.</A>
<P>Speed on the drive is quite good - the Jaz drive has an average of 12ms
seek times, compared to the 29ms of the Zip drive.&nbsp; This provides
the sort of file management I was looking for by allowing me to simply
copy files to and from the drive and at a speed comparable to my regular
disk drives.&nbsp; Its certainly faster than the floppy tape solution.
<P>As I was writing this article I started to consider if I had gotten
my moneys worth.&nbsp; The Jaz drive runs about $299US for an external
SCSI drive, about $199US for internal drives.&nbsp; Compared to the floppy
tape I got about twice the storage space for about twice the price.&nbsp;
At least I thought I had, until I added in the cost of the SCSI card and
the media.&nbsp; The cost for the SCSI card I can significantly reduce
by making full use of the 7 devices I can connect to it, but it still ran
about $240US.&nbsp; The media, on the other hand is significantly higher.&nbsp;
Travan 3 tapes (which are what you use with the floppy tape drive) run
about $30US or so (I think - its been awhile since I purchased them).&nbsp;
The Jaz cartridges are $125US each!&nbsp; You can save a little by purchasing
them in packs of 3 for about $300US.&nbsp; The good news here is that recent
court rulings have allowed another company (whose name escapes me right
now) to sell Zip and Jaz compatible media here in the US.&nbsp; The result
should be a drop in the price of the media over the next 6 months to a
year.&nbsp; The one cartridge I have now will hold me for another couple
of months at least.&nbsp; By then, keeping my fingers crossed, I'll be
able to get a 3 pack for $250 or less.
<P>So, adding the Iomega Jaz drive was simple enough.&nbsp; The information
and software provided by Bob Willmot (the Jaztools author) made getting
the cartridge running almost a no-brainer.&nbsp; And I now have over a
Gigabyte of external storage that I can access nearly as fast as my regular
hard drives.&nbsp; All things considered, its been one of my better investments.
<BR>&nbsp;
<BR>&nbsp;
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<H2>
<A NAME="xserver"></A>X Server Update Part II - Metro Link</H2>
Last month I provided the first part of an update on 3D support available
in X Servers and from other places.&nbsp; I had gotten a number of emails
from readers asking where they could find drivers for various 3D video
cards.&nbsp; I also wanted to find out to what extent the X Input Extension
is supported.&nbsp; Since I hadn't done so in the past, I decided to contact
the various X server vendors and see what they had to say on the subject.&nbsp;
<P>I sent out a query to the 4 X server vendors I knew of:&nbsp; Xi Graphics,
Metro Link, XFree86 and S.u.S.E.&nbsp; The query read as follows:&nbsp;
<P><I>Do you have any information which I may use in my column related
to your current or planned support for 3D hardware acceleration (specifically
related to OpenGL/Mesa, but not necessarily so)?&nbsp; What about support
for alternative input devices via the X Input Extension.&nbsp; The GIMP,
and its X toolkit Gtk, both make use of X Input if available and I expect
many other tools will do so as well in the near future.</I>&nbsp;
<P>Last months article covered 3 vendors, Xi Graphics and XFree86/S.u.S.E,
plus the Mesa package.&nbsp; This month I'll cover <A HREF="http://www.metrolink.com/">Metro
Link</A>.&nbsp; Due to a bit of poor time managment on my part, I wasn't
able to cover Metro Link at the same time as the others.&nbsp; My apologies
to all parties for this.&nbsp;
<P>While reading this article please keep in mind that my intent was to
simply query for information about X Input and 3D hardware support.&nbsp;
It is not intended for this to be a comparison of the vendors products
nor do I offer any editorial on the quality of their products.&nbsp; I
have tried to remove some of the marketing information both from last months
article and this months, but I also want to be fair to the respondents
and provide as much of the information that they provided that is relevent
to the topic.&nbsp;
<P>My first contact with Metro Link was through the assistance of Dirk
Hohndel at S.u.S.E., who forwarded my request to Garry M. Paxinos.&nbsp;
Garry was quite helpful and offered information on his own and had Chris
Bare contact me with additional information.&nbsp;
<P>Garry first provided me with a few dates:&nbsp;
<UL>
<LI>
March 30 - Metro-X 4.3 server release.</LI>
<LI>
May - CDE 2.1.10</LI>
<LI>
July - Hardware Accelerated OpenGL</LI>
</UL>
This he followed up with a little more detail:&nbsp;
<UL>We have a Level II OpenGL source code license from SGI.&nbsp; This
makes it difficult for us to work with GPL'd source.&nbsp; We have been
shipping a software only version of OpenGL since October 8, 1995.&nbsp;
Due to both the competitive nature of this activity and that things might
change before release, it is rather difficult for us to have detailed comments
on:&nbsp;
<UL>
<LI>
Architectural issues.</LI>
<LI>
Chip/Board Support</LI>
<LI>
Relationships with Chip/Board Vendors (most are under NDA anyway)</LI>
<LI>
Relationships with OS vendors</LI>
<BR>&nbsp;</UL>
We plan on making our plans public when we get closer to our release.&nbsp;
Count on quite a few press releases.&nbsp;
<BR>&nbsp;</UL>
&nbsp;
<BR>&nbsp;
<CENTER><A HREF="#next-column">-Top of next column-</A></CENTER>
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<TD WIDTH="49%" NOSAVE><LH><A NAME="next-column"></A><B>More Musings...</B>&nbsp;</LH>&nbsp;
<UL>
<LI>
<A HREF="xfpovray.html">XFPovray</A></LI>
</UL>
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<UL>Current plans are for 3 to 4 specific chip types to be supported in
our initial OpenGL hardware release.&nbsp; We plan on supporting at least
two different CPUs in that release.&nbsp; We've had a policy since our
FCS (First Customer Shipment) back in 1995 that all customers will receive
a copy of the hardware version when it is released.</UL>
Garry noted that Metro Link supports 5 different CPUs:&nbsp; x86, PPC,
Alpha, 68k, and Sparc.&nbsp; He also mentioned that they support multiple
operating systems.&nbsp; Although I didn't mention it last month, both
XFree86 and Xi Graphics servers are also available for other operating
systems besides Linux.&nbsp;
<P>Not long after my first contact with Garry, Chris Bare provided a more
detailed description of what is in the works.&nbsp; Chris is the engineer
responsible for Metro Link's X Input Support.&nbsp;
<UL>Metro-X 4.3 (due out in the next month or so as I write this) will
include support for dynamically loadable X Input driver modules. The 4.3
release will include drivers for Elo Graphics, Carroll, Micro Touch and
Lucas/Deeco touch screens. We are also going to make available a skeleton
driver and documentation for anyone interested in supporting devices on
their own.&nbsp; This technology will also be donated to Xfree86 for inclusion
in one of their future releases.&nbsp;
<P>Our graphical configuration tool provides a fast and accurate on-screen
calibration procedure for any supported touch screen.&nbsp;
<P>Future plans include support for the Wacom tablet as a loadable X Input
module and support for 3D input devices like the Space Orb. We are interested
in supporting any device there is a reasonably demand for, so if there
are any devices your readers have asked about, please let me know.</UL>
As you can see, Metro Link did not list specific boards which they plan
to support.&nbsp; Neither XFree86 nor Xi specifically mentioned any boards
last month.&nbsp; There appears to be quite of bit of work in the pipe
line, however, and according the Garry we should see a flurry of announcements
in the relative near term.&nbsp; Chris does point out some specific input
devices that will be supported in the next release, however.&nbsp;
<P><B>Contact Information</B>&nbsp;
<UL>
<LI>
Announcement: <A HREF="news:comp.os.linux.announce">comp.os.linux.announce</A>&nbsp;</LI>
<LI>
Web Site: <A HREF="http://www.metrolink.com">http://www.metrolink.com</A>&nbsp;</LI>
<LI>
Business:&nbsp; <A HREF="mailto:sales@metrolink.com">sales@metrolink.com</A>,
which is an autoresponder&nbsp;</LI>
<LI>
Human sales contact:&nbsp; <A HREF="mailto:holly@metrolink.com">holly@metrolink.com</A>&nbsp;</LI>
</UL>
Garry added:&nbsp; We do make announcments to c.o.l.a.&nbsp; And we are
working on updating our web site including plans on keeping it up to date.
The sales@metrolink.com address is our standard public address.&nbsp;&nbsp;&nbsp;
However, that is an autoresponder.&nbsp;&nbsp; The address holly@metrolink.com
is referenced in the autoreply and is the 'human' that handles any sales
questions manualy.</TD>
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The following links are just starting points for finding more information
about computer graphics and multimedia in general for Linux systems. If
you have some application specific information for me, I'll add them to
my other pages or you can contact the maintainer of some other web site.
I'll consider adding other general references here, but application or
site specific information needs to go into one of the following general
references and not listed here.
<BR>&nbsp;
<TABLE BORDER=0 COLS=2 WIDTH="100%" NOSAVE >
<TR NOSAVE>
<TD NOSAVE>Online Magazines and News sources
<BR><A HREF="http://www.news.com/">C|Net Tech News</A>
<BR><A HREF="http://www.eklektix.com/lwn/">Linux Weekly News</A>
<BR><A HREF="http://slashdot.org/">Slashdot.org</A>
<P>General Web Sites
<BR><A HREF="http://www.graphics-muse.org/linux/lgh.html">Linux Graphics
mini-Howto</A>&nbsp;
<BR><A HREF="http://www.graphics-muse.org/ugu/ugu.html">Unix Graphics Utilities</A>&nbsp;
<BR><A HREF="http://www.digiserve.com/ar/linux-snd/">Linux Multimedia Page</A>&nbsp;
<P>Some of the Mailing Lists and Newsgroups I keep an eye on and where
I get much of the information in this column:&nbsp;
<BR><A HREF="http://www.gimp.org">The Gimp User and Gimp Developer Mailing
Lists</A>.&nbsp;
<BR><A HREF="http://www.irtc.org">The IRTC-L discussion list</A>&nbsp;
<BR><A HREF="news:comp.graphics.rendering.raytracing">comp.graphics.rendering.raytracing</A>&nbsp;
<BR><A HREF="news:comp.graphics.rendering.renderman">comp.graphics.rendering.renderman</A>&nbsp;
<BR><A HREF="news:comp.graphics.api.opengl">comp.graphics.api.opengl</A>&nbsp;
<BR><A HREF="news:comp.os.linux.announce">comp.os.linux.announce</A>&nbsp;</TD>
<TD><IMG SRC="../gx/hammel/gmuse.jpg" HSPACE=10 HEIGHT=270 WIDTH=190></TD>
</TR>
</TABLE>
<A NAME="future"></A>
<H2>
Future Directions</H2>
Next month:&nbsp; XFont3D/Font3D probably.&nbsp; Beyond that I'm not certain
yet.
<P><A HREF="mailto:mjhammel@graphics-muse.org">Let me know what you'd like
to hear about!</A>
<P>
<HR WIDTH="100%">
<DIV ALIGN=right><FONT SIZE=-1>&copy; 1998 <A HREF="mailto:mjhammel@graphics-muse.org">Michael
J. Hammel</A></FONT></DIV>
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, Michael J. Hammel <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
<!--===================================================================-->
<P> <hr> <P>
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<H4>
"Linux Gazette...<I>making Linux just a little more fun!</I>"
</H4>
<P> <HR> <P>
<!--===================================================================-->
<!-- =============================================================
This Page Designed by Michael J. Hammel.
Permission to use all graphics and other content for private,
non-commerical use is granted provided you give me (or the
original authors/artists) credit for the work.
CD-ROM distributors and commercial ventures interested in
providing the Graphics Muse for a fee must contact me,
Michael J. Hammel (mjhammel@csn.net), for permission.
============================================================= !--><A NAME="musings"></A>
<TABLE>
<TR>
<TD>
<H2>
More...</H2>
<IMG SRC="../gx/hammel/musings.gif" ALT="Musings" HEIGHT=52 WIDTH=247 ALIGN=LEFT>&nbsp;</TD>
</TR>
</TABLE>
&nbsp;
<TABLE>
<TR>
<TD></TD>
</TR>
</TABLE>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" VSPACE=5 HEIGHT=1 WIDTH=1 ALIGN=LEFT>
<TABLE WIDTH="100%" >
<TR>
<TD ALIGN=RIGHT WIDTH="100%"><FONT SIZE=-2>&copy; 1998 <A HREF="mailto:mjhammel@csn.net">Michael
J. Hammel</A>&nbsp;</FONT></TD>
</TR>
<TR>
<TD VALIGN=TOP BGCOLOR="#000000" cellpadding="0" cellspacing="0"><IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN=LEFT></TD>
</TR>
</TABLE>
<A NAME="1"></A>
<H2>
XFPovray 1.2.4/1.3.1</H2>
Recently I was commissioned to work on another cover for the Linux Journal.&nbsp;
The cover will be out in a few months and I don't want to say too much
about it right now, but part of what I needed to do for it was create some
3D text.&nbsp; I've been familiar with how to do this for some time, using
any of a number of tools: AC3D, POV-Ray, Font3D, and so forth.&nbsp; I
have found the quickest 3D text can be created using Font3D and POV-Ray.&nbsp;
The results are generally pretty good.&nbsp; I hope to give you some insight
into Font3D and its XForms front end, XFont3D, next month.
<P>After the fonts were created I needed to run POV-Ray.&nbsp; This is
a terrific command line tool for creating 3D images that uses its own language
for defining a 3D scene.&nbsp; The scene file is fed to the rendering engine
using any combination of the many command line options.&nbsp; The only
real problem with POV-Ray is that is has so many options it is easy to
forget which ones use which particular syntax.
<P>Fortunately, <A HREF="mailto:mallozzir@cspar.uah.edu">Robert S. Mallozzi
</A>has written a very useful XForms based front end to the POV-Ray renderer:&nbsp;
<A HREF="http://cspar.uah.edu/~mallozzir/html/xfpovray.html">XFPovray</A>.&nbsp;
The tool, like many for Linux, is available in source.&nbsp; It requires
the <A HREF="http://bragg.phys.uwm.edu/xforms">XForms</A> v0.88 or later
library and will work with <A HREF="http://www.povray.org">POV-Ray 3.0</A>.&nbsp;
I had been running the 1.2.4 version for the work on the cover art, but
while writing this article I found that Robert had released a newer version.&nbsp;
I downloaded that one and had no problems building it.&nbsp; Its just a
matter of editing 2 files (if necessary), and running <B>xmkf; make; make
install.</B>&nbsp; You'll need to be root to run the default install, since
the Imakefile is set up to install in /usr/local/bin.
<BR>&nbsp;
<CENTER><TABLE BORDER=0 COLS=2 WIDTH="450" NOSAVE >
<TR NOSAVE>
<TD ROWSPAN="2" NOSAVE>
<TABLE BORDER=0 COLS=1 WIDTH="100%" NOSAVE >
<TR>
<TD><IMG SRC="./gx/hammel/xfpovray-1.jpg" HSPACE=10 VSPACE=10 HEIGHT=162 WIDTH=311></TD>
</TR>
<TR NOSAVE>
<TD ALIGN=CENTER NOSAVE><B>Figure 1: XFPovray v1.3.1 interface</B></TD>
</TR>
<TR NOSAVE>
<TD NOSAVE>The interface to 1.3.1 is a little different from the 1.2.4
version, using a smaller footprint for the initial window.&nbsp; The Render
options are also now in a notebook widget.&nbsp; Overall the interface
is more compact.&nbsp;&nbsp;&nbsp; Unfortunately, I found that something
wasn't quite right with my configuration.&nbsp; At times the menus would
not cause window refreshes when the menu was close, leaving bits of the
menus covering other parts of the underlying windows.&nbsp; This may be
a bug in XForms 0.88, but the 1.2.4 version of XFPovray didn't seem to
have this problem.&nbsp; Because of this, I'm going to review the 1.2.4
version, with just a few comparisons made to the 1.3.1 version.&nbsp; The
features of both are very similar and both versions are available on the
XFPovray web site.&nbsp; If you have problems with the 1.3.1 version you
can grab the 1.2.4 version.&nbsp;</TD>
</TR>
</TABLE>
&nbsp;</TD>
<TD NOSAVE><IMG SRC="./gx/hammel/xfpovray-1b.jpg" HSPACE=10 VSPACE=10 HEIGHT=396 WIDTH=279></TD>
</TR>
<TR NOSAVE>
<TD ALIGN=CENTER NOSAVE><B>Figure 2:&nbsp; XFPovray 1.2.4 interface</B></TD>
</TR>
</TABLE></CENTER>
XFPovray provides the user the ability to run the POV-Ray renderer on existing
scene files and to edit those files.&nbsp; To edit a scene file you need
to first configure the editor of choice.&nbsp; Select the <I>Options->Configure
</I>menu item from the menu bar of the main window.&nbsp; A dialog will
open allowing you to configure the editor you wish to use, along with the
location of the POV-Ray executable, an image viewer and a number of other
general items.&nbsp; After you click on the Accept button you will need
to use the <I>Options->Save State </I>menu option to save the configuration
to XFPovray's configuration file directory.&nbsp; This wil be $HOME/.xfpovray
by default.
<P>Once you've selected an editor you are ready to edit a file.&nbsp; Click
on the Scene File button to open a dialog box.&nbsp; This button sets the
default scene file to be rendered.&nbsp; You should do this first before
trying to edit any of your include files.&nbsp; The dialog box that opens
is a file selection box.&nbsp; This dialog has changed in the 1.3.1 version
to a format that is a little more standard for such dialogs.&nbsp; Figures
3 and 4 show the two versions of the file selection dialog.
<BR>&nbsp;
<TABLE BORDER=0 COLS=2 WIDTH="100%" NOSAVE >
<TR NOSAVE>
<TD ALIGN=CENTER NOSAVE><IMG SRC="./gx/hammel/xfpovray-3.jpg" HSPACE=10 VSPACE=10 HEIGHT=355 WIDTH=313></TD>
<TD ALIGN=CENTER NOSAVE><IMG SRC="./gx/hammel/xfpovray-4.jpg" HSPACE=10 VSPACE=10 HEIGHT=335 WIDTH=362></TD>
</TR>
<TR NOSAVE>
<TD ALIGN=CENTER NOSAVE><B>Figure 3:&nbsp; File Selection box for XFPovray
1.2.4</B></TD>
<TD ALIGN=CENTER NOSAVE><B>Figure 4:&nbsp; File Selection box for XFPovray
1.3.1</B></TD>
</TR>
</TABLE>
<P>The Scene File button only establishes the file which will be passed
to the renderer.&nbsp; It does't open the editor on that file.&nbsp; To
open the editor you next choose the Edit Scene button.&nbsp; Again, the
File Selection window opens.&nbsp; In the 1.3.1 version the default file
in this dialog is the file you chose with the Scene File button.&nbsp;
In the 1.2.4 version you start in whatever directory you started XFPovray
in originally.&nbsp; You can edit a file by clicking on it or use the dialog
to choose another file.&nbsp; Once you've selected a file the editor will
open into that file and your ready to do your work.
<P>The View Image button will simply launch an image viewer on a particular
image file.&nbsp; The Config File button will display the configuration
file used for POV-Ray (not for XFPovray).&nbsp; The settings for many of
these can be changed from Render Options (buttons in 1.2.4, a notebook
with tabs in 1.3.1), although there doesn't appear to be a way to save
the changes from the interface.&nbsp; If the defaults are not to your liking,
you can always edit the configuration file (xfpovray.ini) by hand.
<P>The rendering options cover a large number of POV-Ray options, but a
few options are not yet supported (see the web page for details on what
isn't supported).&nbsp; Figures 5 and 6 show the Rendering Options windows
for the two versions of XFPovray.&nbsp; Figure 6 was cropped from the main
window to save a little space.&nbsp; The render options in version 1.2.4
are displayed in the space occcupied by the povray banner image.&nbsp;
Figure 7 shows the tabs in the Render Options window for version 1.3.1.&nbsp;
As you can see, there are quite a few options you can configure from these
windows.&nbsp; Keep in mind that version 1.2.4 has the most of the same
options as 1.3.1, except with 1.2.4 you access them from a set of Render
Options buttons in the main window.
<BR>&nbsp;
<BR>&nbsp;
<TABLE BORDER=0 COLS=1 WIDTH="100%" NOSAVE >
<TR NOSAVE>
<TD ALIGN=CENTER NOSAVE><IMG SRC="./gx/hammel/xfpovray-5.jpg" HSPACE=10 VSPACE=10 HEIGHT=313 WIDTH=414></TD>
</TR>
<TR NOSAVE>
<TD ALIGN=CENTER NOSAVE><B>Figure 5:&nbsp; Render Options, version 1.2.4</B></TD>
</TR>
<TR NOSAVE>
<TD ALIGN=CENTER NOSAVE><IMG SRC="./gx/hammel/xfpovray-6.jpg" HSPACE=10 VSPACE=10 HEIGHT=400 WIDTH=428></TD>
</TR>
<TR NOSAVE>
<TD ALIGN=CENTER NOSAVE><B>Figure 6:&nbsp; Render Options, version 1.3.1</B></TD>
</TR>
</TABLE>
&nbsp;
<P>Figures 7 and 8 show some of the possible templates you can use when
editing a scene file.&nbsp; Templates are examples of the various primitives
and command syntax you will use in a POV-Ray scene file.&nbsp; To use these
templates, you first select the template you want to add to your scene
file (we're assuming the scene file is already opened and currently being
edited).&nbsp; This copies the template to the primary X selection buffer.&nbsp;
This is the same buffer you use when you highlight some text in an xterm
window.&nbsp; To use the copy of the template you first enter insert mode
in your editor and then use the middle mouse button (or both buttons on
a 2 button mouse that is emulating a 3 button mouse) to paste the selection
into your file.&nbsp; Note that when you select the template from the menus
you won't see any sort of confirmation that the template has been placed
in the selection buffer.
<BR>&nbsp;
<BR>&nbsp;
<TABLE BORDER=0 COLS=1 WIDTH="100%" NOSAVE >
<TR NOSAVE>
<TD ALIGN=CENTER NOSAVE><IMG SRC="./gx/hammel/xfpovray-templates.jpg" HSPACE=10 VSPACE=10 HEIGHT=299 WIDTH=415></TD>
</TR>
<TR NOSAVE>
<TD ALIGN=CENTER NOSAVE><B>Figure 7:&nbsp; The solid primitive templates</B></TD>
</TR>
<TR NOSAVE>
<TD ALIGN=CENTER NOSAVE><IMG SRC="./gx/hammel/xfpovray-templates-2.jpg" HSPACE=10 VSPACE=10 HEIGHT=237 WIDTH=415></TD>
</TR>
<TR NOSAVE>
<TD ALIGN=CENTER NOSAVE><B>Figure 8:&nbsp; Camera primitve templates</B></TD>
</TR>
</TABLE>
&nbsp;
<P>Once you've finished editing the file you can render a preview of the
image.&nbsp; Use the <I>Render Options/Output </I>feature to specify the
size of the preview.&nbsp; You can even use the <I>Inc Preview</I> button
to sample the effects provided by the standard include files!&nbsp; The
preview uses the selected texture, color, or whatever on a sphere.&nbsp;
You can specify the direction of lights and the camera position for the
preview as well.&nbsp; This makes selecting the features to add to an objects
texture much simpler and less error prone.&nbsp; Although there is still
a bit of trial an error involved with creating the textures, you can at
least sample some of the effects quickly and easily.
<P>One last thing you should know before trying XFPovray.&nbsp; I&nbsp;mentioned
earlier that I&nbsp;tried both the 1.2.4 and 1.3.1 versions.&nbsp; If you
run the earlier version first, then upgrade to the 1.3.1 version the program
seems to recognize the differences in the configuration files.&nbsp; However,
if you have problems with 1.3.1 and want to fall back to 1.2.4 you will
need to first clean out the files in the $HOME/.xfpovray directory.&nbsp;
The earlier version will get confused by the changes to the config files
that 1.3.1 uses.&nbsp; Its not a real concern, of course, if you don't
try to back track to from the later to the earlier version.
<P>All in all, XFPovray is quite a useful tool.&nbsp; When I&nbsp;was working
on my 3D text I first generated the include files of the text using Font3D/XFont3D.&nbsp;
After that, I was able to work completely from within XFPovray to sample
the images and experiment with minor changes quickly.&nbsp; I never had
to run the POV-Ray executable by hand, which was a real bonus since I never
can remember the correct command line options.&nbsp; If you do much work
with POV-Ray, I think you'll enjoy using XFPovray as your editing/rendering
front end.
<BR>&nbsp;
<TABLE WIDTH="100%" >
<TR>
<TD VALIGN=TOP COLSPAN="4" BGCOLOR="#000000" cellpadding="0" cellspacing="0"><IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN=LEFT></TD>
</TR>
</TABLE>
&nbsp;
<TABLE WIDTH="100%" >
<TR>
<TD ALIGN=RIGHT><FONT SIZE=-2>&copy; 1998 by <A HREF="mailto:mjhammel@csn.net">Michael
J. Hammel</A>&nbsp;</FONT></TD>
</TR>
</TABLE>
&nbsp;
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, Michael J. Hammel <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
<!--===================================================================-->
<P> <hr> <P>
<A HREF="./gm.html"><IMG SRC="../gx/back2.gif"
ALT=" Back "></A>
<H4>
"Linux Gazette...<I>making Linux just a little more fun!</I>"
</H4>
<P> <HR> <P>
<!--===================================================================-->
<center>
<H2>Linus Speaks at SVLUG Meeting</H2>
<H4>By <a href="mailto:chris@dibona.com">Chris DiBona</a></H4>
</center>
<P> <HR> <P>
<A HREF="./svlug.html">SVLUG Photo Album</A>
<P> <HR> <P>
When we gave the job of arranging speakers to Sam Ockman, we never doubted
his ability to bring in terrific speakers. His first speaker for our
January meeting was his personal hero, H. Peter Anvin. For February, we had
two speakers: Eric Raymond of "The Cathedral and the Bazaar" fame and Bruce
Perens of Debian. Therefore, the question became "How do you top these
Linux luminaries?" Sam's answer was our March speaker, Linus Torvalds.
<P>
Until December, the Silicon Valley Linux Users Group (of which I am the
Vice President) had met in the back dining room of the local Carl's Jr.
(local burger chain). Carl's held around 40-50 people tightly. We had been
talking about moving the meeting from this spot for some time, and some of
our members who worked at Cisco pleaded to get a room for us
for the Eric Raymond meeting in February. As expected, this meeting was standing
room only, and we knew that with Linus coming we needed a much
larger space. Again, Cisco (with Ben Woodard pushing it through) came
through for us with a room rated for 350 people in their Gateway
Conference center.
<P>
About a half hour before the meeting began, the chairs were full and
people began to sit on the floor, against the walls and all
around the room.
Approximately 500 people had come to hear Linux speak.
We were
lucky--the air conditioning was in good shape, and
the fire marshal didn't show up.
<P>
The meeting began and after the user-group formalities were complete,
Linus was presented with the VA Research Excellence in Open Source
Software Award, co-sponsored by Red Hat and O'Reilly. The prize was a
loaded dual Pentium 333 from VA Research. In fact, Linus made out very
well, receiving not only the computer just mentioned, but also a Palm Pilot
professional
from Klaus Schulz of 3Com and a six-pack of real beer from local legend Rick
Moen. It should be noted that Linus didn't know about any of these awards
before coming to the meeting.
<P>
Accompanied by thunderous applause, Linus stood before the podium and expressed
his shock at the number of people who had showed up to hear him speak. He
had been under the impression that it would be a small, intimate meeting
like the first one he had attended last year at the burger joint.
<P>
He began his speech by telling the group what he wouldn't be talking about.
He said he wouldn't be talking about user issues or MIS issues--all
he would talk about was what he was doing with the kernel.
<P>
The hour-long speech (not counting the Q&A afterward)
was a technical discussion of how he is improving SMP (symmetric
multi-processing) support in the kernel.
He talked about the challenges of moving from a single
kernel resource lock for all CPUs as in the 2.0.x kernels to
individual resource locks for the new kernels. He discussed the ways these
changes affect things internally for the kernel, and how it affects the
handling of shared memory, interrupts and I/O. Linus also spent some time
talking about how the file system is being changed internally for better
performance. The speech will be available on-line by the time this article
goes to print (see Resources below), I'd recommend that you download it
and listen to the whole thing.
<P>
In addition to videotaping the speech and taking still photos,
the meeting in its entirety was broadcast over the MBone (Internet
protocol multicast backbone). After Linus had finished speaking, all of the
door prizes were given out, and everyone left the meeting happier and smarter
than they were the day before.
Special thanks are due to Linus Torvalds for speaking and to
everyone else involved in making this meeting a success.
<P>
<H4>Resources</H4>
<ul>
<li>SVLUG: <A HREF="http://www.svlug.org/">http://www.svlug.org/</A>
<li>REDHAT: <A HREF="http://www.redhat.com/">http://www.redhat.com/</A>
<li>VA Research: <A HREF="http://www.varesearch.com/">http://www.varesearch.com/</A>
<li>O'Reilly: <A HREF="http://www.ora.com/">http://www.ora.com/</A>
</ul>
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, Chris DiBona <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
<!--===================================================================-->
<P> <hr> <P>
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ALT="[ TABLE OF CONTENTS ]"></A>
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</H4>
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<!--===================================================================-->
<center>
<H2>Markup Languages and lout2</H2>
<H4>By <a href="mailto:murray@zeus.mpce.mq.edu.au">Murray Adelman</a></H4>
</center>
<P> <HR> <P>
<B>lout</B> is a markup processor written by Jeffrey Kingston which
produces Postscript output instead of a device independent file. It's
underlying design was developed by the author and it allows it to
offer essentially the capabilities of LaTeX with the simplicity of
maintenance and resource requirements of <B>troff</B>. At the same time
it is easier to make changes to its behaviour than it is with the
other two. The details of the design are beyond the scope of this
article. It is described in the documentation and I will discuss where
you can read about it in more detail at the end of the article when I
discuss documentation.
<p>
<B>Basser lout</B> is an implementation of lout for the
UNIX operating system and that is the one I will discuss. It is the
one that would be installed on Linux. From now on when I say
lout, I will mean Basser lout. The package provides special
languages for graphics, tables, equations, and graphs as well as macro
facilities. It is able to automatically handle cross references,
create indexes, tables of contents and bibliographies from a
database all in an integrated environment.
<p>
<H4>Installing Lout</H4>
<p>
<B>lout</B> can be obtained from ftp//:ftp.cs.su.oz.au/jeff/lout
This article is based upon version 3.08 which is in the file
lout.3.08.tar.gz.
<p>
There might be a newer version by the time you read this, but the
author of lout tells me these step-by-step instructions will
still apply.
<p>
I strongly suggest you also get lout.teq.2.0.tar.gz. You can
have a preview of the users' guide if you get
lout.3.08.user.ps.gz. This (after it is uncompressed) can be
viewed with a postscript previewer or (its two hundred pages) can be
printed out.
<p>
When you unpack lout.3.08.tar.gz (using <tt>tar -zxpf
lout.3.08.tar.gz</tt>), you will have a directory called
lout.3.08 which includes the source files, a makefile,
several directories, and a few other files. Binaries are not
provided. The makefile is very well written and the source compiles
cleanly under Linux. I tried it with a.out using version 1.2.3 and
with ELF using versions 1.3.35 and 1.2.20 of the kernel, and none of
them gave any trouble. The instructions for how to compile are at the
top of the makefile and you need make little changes to the original
one. (If you are paranoid like me you will <tt>cp makefile
makefile.dist</tt> before editing this file.) The mandatory changes
are to reset the directories BINDIR, LIBDIR, DOCDIR, and MANDIR. If
you have root privileges you can set them to whatever you like except
that the installation process assumes that BINDIR, and MANDIR already
exist. This is a good idea since BINDIR must be on every users' PATH
and MANDIR must be in their MANPATH. If you are indecisive, let me
suggest:
<pre>
BINDIR = /usr/local/bin
LIBDIR = /usr/local/lib/lout
DOCDIR = /usr/doc/lout
MANDIR = /usr/local/man/man1
</pre>
If you want to install it in an unconventional place, in directories
that don't exist then create the directories BINDIR and MANDIR. I will
refer to these directories generically as BINDIR, DOCDIR, etc. from
now on.
<p>
Most of the other macros should be left as is. Make sure OSUNIX is set
to 1 and the others, OSDOS and OSMAC are set to 0 (zero). (They
already were in my copy). That is:
<pre>
OSUNIX = 1
OSDOS = 0
OSMAC = 0
</PRE>
If you want French and/or German support read the instructions (in the
makefile) for the macros USELOC and LOC_XX. (Where XX is FR or
DE.) For just English support you should have:
<pre>
CHARIN = 1
CHAROUT = 0
USELOC = 0
#LOC_FR = fr
#LOC_DE = de
</PRE>
Uncomment the relevant commented ones for language support. Choosing
one of the languages will allow lout to speak to you in those
languages when it gives messages. There is also support for formatting
in many languages including language specific hyphenation rules. These
options can be chosen at run time.
<p>
Now just do <tt>make lout</tt> followed by <tt>make c2lout</tt> when
this is finished, followed by <tt>make install</tt>. This last
command does a lot, including customizing the installation to your
setup. You have to do some hand editing of some files if your site
doesn't use A4 paper. This is a matter of editing a text file with a
text editor and it is well documented in the makefile. If you prefer
your error messages in a language other than English. You will find
instructions in the makefile for this.
<p>
The next step is to do <tt>make clean</tt> to get rid of all the extra
files produced in the building of the binaries. This leaves the
original sources intact. It also leaves your modified makefile
intact. If you understand where the different files go, you might want
to try it out before cleaning up, because if the installation
procedure is at fault you can fix up your makefile and try again,
saving compiler time.
<p>
If you have some time on your hands, you can test the installation by
making the user's guide. The instructions are in a README in the
DOCDIR/user directory. It takes some time, especially on a
slow computer. If you follow the instructions the result will be a
Postscript file called op. I renamed mine to
users.ps and I keep it permanently in the
DOCDIR/user directory set to be world readable. This, of
course, requires a Postscript viewer. I strongly suggest that you have
<B>ghostview</B> installed if you want to use lout seriously.
The user's guide is a huge document of about two-hundred pages,
complete with a table of contents and an index. You will eventually
need it! If you don't want to make it yourself, you can uncompress
lout.3.08.user.ps.gz.
<p>
As a quicker and far less exhaustive test you can use the file
sample.lt that I use for illustrating the language below. It
is complete and self contained. <B>lout</B> writes a few files and
leaves them on the disc when it is finished, for future use with the
same document, so choose a directory where you have write privilege
and will be able to easily locate and remove these extra files when
you are through testing and experimenting with them. Here is
sample.lt:
<pre>
(1) @SysInclude{doc}
(2) @Doc @Text @Begin
(3) @LD @Heading{Hello World}
(4)
(5) Hello
(6) -90d @Rotate{World Hello World 1.5 @Scale Hello}
(7) World Hello
(8) +45d @Rotate{World}
(9) Hello World Hello World Hello World
(10) @ShadowBox{Hello World}
(11) .7 @Scale{Hello .7 @Scale{ World .7 @Scale{Hello}}}
(12) World
(13) red @Color Hello World! Hello World
(14) @Box paint{grey} white @Color{Hello World Hello World}
(15) green @Color 120p @Font .
(16) @End @Text
</PRE>
Then do:
<pre>
lout sample.lt>sample.ps
</PRE>
You should get the prompt back in a few seconds with no error messages
in-between. Now on disk you have the files: sample.lt (This
is the source file you wrote yourself), lout.li,
sample.ld, and sample.ps. You can now print or
preview the file sample.ps. I have added a number of
effects. These effects are all built into lout and should be
shown off. I am not claiming that the other formatters won't do the
same thing, but lout will do it better for reasons I will go
into later.
<p>
<H4>The Language</H4>
<p>
Like TeX, lout partitions characters into the categories:
letters, punctuation, space, quote, escape, and comment. Letters are
the upper and lower alphabetic and the character
@. Punctuation characters are the usual ones including the
various forms of braces and funnily enough, the numerals. Spaces are
the space, tab, and newline characters. The last three categories have
only one member each. Quote has ' , escape has \,
and comment has #. The comment character at any place on a
line in the source file causes lout to ignore the rest of the
line.
<p>
You will deduce from the file sample.lt that commands start
with @. That is a custom rather than a law. A command can be
named by any string of letters. If you wish to write filters later to
manipulate your source file using regular expressions, I suggest that
you keep to the custom. This naming freedom comes with
responsibility. Remember in sample.tex there were
concatenations of commands with no space between them. TeX will deduce
that a command has ended when it sees the sign of a new one
beginning. This is not the case with lout. If lout sees a
string starting with @ that it doesn't recognize as a command
it notify you of the fact on the screen for your information. Look at
last line of sample.lt. There are two commands <tt>@End</tt>
and <tt>@Text</tt>. If you were to forget the space between them and
write <tt>@End@Text</tt>, lout would see that the string is not
bound to a known command and would treat it like text. Seeing that it
starts with an @ it would politely warn you that the command
is unknown. On the other hand if line (13) were to start with
<tt>red@Color</tt>, the string would just be typeset literally with no
warning. There is no command <tt>\Color</tt> as part of standard TeX
but if there were and you wrote red\Color, TeX would still know that
<tt>\Color</tt> was a command.
<p>
Another unusual feature of the lout markup language is that its
commands take arguments on both the left and on the right. The command
<tt>Color</tt> takes the color as the left argument and the text to
bear this color as a right one. Our example at the beginning of line
(13) will print "Hello" in red. In general arguments that
control things go on the left and arguments representing things acted
upon go on the right, but again this is custom rather than law. The
name of a command is delimited on the left and on the right by either
a space or a punctuation symbol. So, as a matter of fact, line (15)
could have been written <tt>green @Color 120p @Font</tt>. (No space
between "Font" and ".".) The same would be true if the
period were replaced by the numeral 1, but if the period were replaced
by the letter "a" the space would be necessary.
<p>
<B>lout</B> works recursively by creating more complex <I>objects</I>
out of simpler objects. A character is an object. A catenation of
characters form an object. A command applied to a string of characters
forms an object, and so on. The whole document is an object. The
general rule for lout is that a space in the source file between
objects produces a space in the final document, but space needed to
delimit objects does not. This is consistent for any character in the
space category. That is "Hello" separated from "World" by
five space characters will be the same as if they were separated by
five newlines which is the same as if they were separated by five
tabs. All would result in there being five spaces in the final
document.
<p>
Let me go through sample.lt. Line (1) tells lout to
read the file doc in the directory LIBDIR/include. This is
called a <I>setup file</I>. It gives the general layout parameters such
as margins, spaces above and below headers, style of page number,
etc. It also calls in two other files called docf and
dl in the same directory. These provide the standard
commands. You can copy any of these to your working directory and
modify them. You would then call them by the command <tt>@Include</tt>
instead of <tt>@SysInclude</tt>[footnote 8. If you know something about
SGML you will see a similarity.. If they are in a different directory
from the working one, you must give an absolute pathname. There are no
environment variables to specify your private cache of setup files,
but a directory can be specified on the command line with the
<tt>-I</tt> flag. I suggest that you make a directory called something
like myinclude in your home directory and alias the
command <tt>lout</tt> to <tt>lout -I ~/myinclude</tt>. Then
invocations of <tt>lout</tt> will cause a search in <tt>myinclude</tt>
for any files specified by the <tt>@Include</tt> command. The next
line contains a standard invocation to begin the text part of a
file. These three commands or longer substitutes must be in each file.
<p>
Line (2) is the statutory declaration for the actual text to begin and
line (3)is the first line of the document. The string <tt>@LD</tt>
there is the command for a Left Display. This groups its argument into
an object and leaves suitable vertical space above and below it. The
default is one line above and one line below. It justifies its
argument with the left margin. If <tt>@LD </tt>were replaced by
<tt>@D</tt>, the display would be centered. The <tt>@Heading{Hello
World}</tt> makes a new object consisting of the string <tt>Hello
World</tt> with the font size and face for a heading. By default this
simply is bold face at the same size as the body. This illustrates
lout's behaviour with respect to arguments. A string up to a
white space is considered a single argument. Here is an analysis of
the formation of the header. <tt>{Hello World}</tt> is an
object. Thus <tt>@Heading</tt> acts upon the object <tt>{Hello
World}</tt> to make a new object which is the string "Hello
World" placed in bold face. Then <tt>@LD</tt> acts on this
object to place it vertically the way a display should be placed and
to align it with the left margin. The net result using the default
settings will be "Hello World" in bold face with a blank
line under it.
<p>
Line (4) is blank. Recall that this will produce a single space in the
document. Since the header ends the line, this won't be visible so the
blank line has no effect. In contrast, the other formatters treat two
newlines differently from one. I like this consistency, but I have the
same complaint about taking newlines literally as I do with
troff. <B>lout</B> offers the option of using either TeX's or
troff's treatment of white spaces instead of the default
one. The TeX rule consistently collapses multiple spaces into one
space. Unlike "real" TeX, a blank line will just produce a space
in the document and not a new paragraph. In my opinion this is the
best of all worlds. If you want to go this route then you have to
write a macro equivalent to TeX's <tt>\hspace</tt> which requests that
a specific amount of horizontal space be left. I will show you one
such later when I discuss macros.
<p>
Line (5) begins the body of the section. Line (6) uses a facility that
is unique to lout. The command <tt>@Rotate</tt> rotates the
object appearing as the right argument by the amount specified in the
left one. I haven't discussed the units of measure used by lout
but you can guess that <tt>d</tt> denotes degrees. Rotations are by
default counter-clockwise so <tt>-90d</tt> means rotate ninety degrees
clockwise. The object to rotate is the complicated one to the right in
curly brackets. I have put other geometric operations inside this
object. The last "Hello" in the rotated string is the
subject of the command <tt>@Scale</tt> which means to scale it. The
argument on the left says how much, in this case a factor of 1.5. A
scaling factor being a pure number needs no units. Note that the
victim of the scaling has no curly braces around it. This is because
it is automatically delimited by a white space.
<p>
Line (7) consists of simple text, because it is on a new line, it is
separated from the rotated object by a space and so is a new object
with a space before lt in the final document.
<p>
Line (8) is another rotation, this time forty-five degrees counter
clockwise. The brackets around its argument "World" are
not necessary, I just put them there to show that you can if you
want.
<p>
Line (9) is just plain text. So far everything I have described will
be set on the same line. It is indeed a high and very deep line
because of the rotated objects, but nonetheless a line. The horizontal
and vertical spacing needed for it has been taken care of
automatically.
<p>
Line (10) puts "Hello World" in a shadow box. One of those
things that have a shadow in the lower right corner to give a three
dimensional effect.
<p>
On line (11) "@Scale" has as its argument the object
<tt>{.7 @Scale{ World .7 @scale{Hello}}</tt> and <tt>.7</tt> as a
parameter. This, in turn has the object <tt>.7 @Scale {World .7
@Scale {Hello}}</tt> as its argument and <tt>.7</tt> as its parameter,
and so on. The net result is of the three words "Hello",
"World", and "Hello" each one smaller than the
one on its left. This illustrates the recursive nature of lout
in building new objects out of already created objects. (I chose those
particular ones to taper off because this is the end of the first line
using the default page setup.
<p>
You can guess that line (12) adds a bit of color to the document. The
only thing to remember is that only the "Hello" will be
red. The use of the colors offered by Postscript are built in to the
formatter. With a black and white printer the color just won't show
up, but there will be no error generated.
<p>
Line (14) looks complicated, but it follows the rules of lout
syntax and is hence was not hard to create with the documentation in
front of me. The first command is <tt>@Box</tt> which draws a
rectangular box around its argument. Some commands can take options
and <tt>@Box</tt> is one of them. The <tt>paint</tt> option specifies
what color to "paint" the inside of the box. The next part
is the object inside the box. The thing in the box is a white colored
string "Hello World Hello World". Note that there is no
need to put curly braces around the whole thing because white
is an argument to <tt>@Color </tt>and the whole shebang just makes a
white object.
<p>
This is further illustrated on line (15) where a huge period is
colored green. The new command is <tt>@Font</tt> which takes a left
and a right argument. The left one is the size and the right argument
is the subject of the font change. In this case we produce a period in
a one hundred-twenty point font and color it green. You might have
noticed that troff allows relative font changes to be
additive. That is you can ask that a font be made larger or smaller by
so many points. Although I didn't illustrate it, TeX on the other hand
favors multiplicative relative changes, that is you can change to a
multiple of the font size. <B>lout</B> offers both. You can specify an
additive change by <tt>+2p @Font</tt>, which will add two points to
the current font size, or you can specify a multiplicative change by
<tt>1.2f @Font</tt>. The unit <tt>f</tt> denotes the current font size
and <tt>1.2f</tt> means the current font size multiplied by a factor
of 1.2. Line (16) contains the compulsory command to end a
document. It must be put in all documents.
<p>
If you have ghostview installed, and if you have the file
sample.lt on disk, you can preview it by first doing <tt>lout
sample.lt > sample.ps</tt> and then <tt>ghostview sample.ps</tt> when
the prompt returns. If you have a color monitor and a color X server
you should see the color effects. You can, of course, print the
Postscript file.
<p>
There are packages provided as part of the distribution for tables,
equations, graphics, and graphs. These are more integrated than they
are in troff. The equation one is very similar to the <B>eqn</B>
of troff. The example I gave for troff will work with
lout almost verbatim. In the section on installation I strongly
suggested getting lout.teq.2.0.tar.gz. This is a modified
equation package using Computer Modern Fonts for the mathematical
symbols. I have made some tests and I think the results do look better
using it. There are instructions on how to use it in the
documentation. If you plan to do a lot of mathematical typesetting you
should install it. It is dead easy to do. Just edit the makefile that
comes with the package to tell it where the various files for lout
have been installed. and do <tt>make</tt>. No compiling or linking is
performed and the process is quick. According to the literature that
comes with the distribution, this packages has not been included in
the lout distribution for legal reasons. The creator of the
fonts requires conditions in the license that are not compatible with
the GNU license under which lout is distributed.
<p>
The tables package has a different syntax from that of troff,
but seems to operate with the same philosophy. The results are good
with the examples I played with but it doesn't offer the scope and
flexibility of <B>tbl</B> for making really complex non-standard
tables; but then again, what does?
<p>
As I said, graphics are built into lout. Nonetheless there is a
graphics package to provide you with advanced features. It provides
the basic objects usually found in drawing packages such as squares,
circles, ellipses, and Bezier curves. These are all parameterized to
allow relevant specification of size and shape. Many of the commands
and parameters are lout versions of Postscript command. The
important difference is that lout does the formatting whereas
Postscript requires you (with the help of its programming constructs)
to account for every point on the page. <B>troff's pic</B> package
offers two levels of drawing. One is a "user-friendly" level in
which you describe the drawing verbally and one that is more
complicated to use which serves as a basis for the other level, and
which allows automating some drawing operations which would otherwise
be tedious. <B>lout's</B> instruction set seems to lie somewhere in
between. On the other hand it is more manageable for the casual user
than TeX's <B>xypic</B> package.
<p>
There is also a package for producing graphs, and one for formatting
<B>C</B> and <B>Pascal</B> code from the sources. My line of work
doesn't involve using them and I haven't tried them as yet.
<p>
<B>lout</B> as it is distributed is not likely to require extra macro
packages. You can do just about any job you need by modifying the
existing ones. It, of course, also has facilities for writing your own
commands. Let me give you a simple one called <tt>@Hspace</tt>. If you
take my advice and use the TeX spacing option you will find it useful:
<pre>
def @Hspace
right x
{|x}
</PRE>
It is named after one that does the same job in TeX where it is called
<tt>\hspace</tt>. It takes one argument and leaves that much
horizontal space. For example <tt>@Hspace .5i</tt> will leave a
horizontal space of one-half inch. Because of the way lout puts
one object to the right of the previous one. There doesn't appear to
be a way to write an equivalent of TeX's <tt>\vskip</tt>. There is, of
course, a primitive for leaving vertical space.
<p>
The documentation that comes with lout instruct you to put
definitions (macros) in a file called mydefs which is
automatically read in when lout processes a document. I have
experimented with putting them in source file along with the text with
varying success. Ones that only use primitives, like <tt>@Hspace</tt>,
can be put at the very top of a document before the
<tt>SysInclude</tt> command. Others that use commands like
<tt>@Color</tt> seem not to work unless they are in mydefs.
<p>
A consequence of the liberality of naming commands is that if you
write the definition
<pre>
def teh
{the}
</PRE>
Whenever you make the common typing mistake of typing "the" as
"teh", lout will automatically change it to the right
word. Of course you have to make a separate one with a capital
"T" and you have to make sure the term "teh" doesn't
appear in your document. This only uses lout primitives and can
be put at the beginning of the document.
<p>
I have used the word recursive in an informal sense above, but
lout is recursive in the technical sense also. You can call a
command within itself. This is the underlying principle behind its
design. There are useful recursive examples given in the expert's
guide. Reading it will give you some idea of how lout is
implemented. I recommend chapter 1 of the expert's guide for general
reading. I will give a useless but fun example here that I hope will
illustrate the point. The lines
<pre>
def @Banner
{red @Colour Hello blue @Color World @Banner}
@Banner
</PRE>
will write a red "Hello" followed by a white space followed by a
blue "World" repeated until a line is filled. If you want to try
it, be sure to put this definition in the mydefs.lt file and
the invocation of it (third line) in a source file.
<p>
This recursive behaviour is used more seriously in the implementation
of lout. It is one of the "secret ingredients" that allows
lout to offer so many facilities in such little space. See the
"Expert's Guide" that comes with the distribution for more
details.
<p>
<B>lout</B> like LaTeX is a logical markup language. The author
indicates what textual elements he or she wants at a given point and
the formatter will take care of the details. With different kinds of
documents these details might be different. For example a section in a
book is numbered differently from one in a simple article. Like LaTeX,
lout takes care of these differences by providing different
style files for different document structures. The ones offered in the
distribution are the <B>doc</B>, <B>report</B>, <B>book</B>, and
<B>slides</B>. The doc style is for simple basic documents such
as a scholarly article. The report style is for technical
reports. The book style is obviously for books, and the
slides style is for making one or a series of overhead projector
slides. If you have a color printer, you can use the color facilities
in lout to great advantage with the slides style. There
are variants of each of these files for output other than Postscript.
<p>
It is difficult to change the defaults in LaTeX style files. I gave an
indication of such a change. It is easier in troff except for
the somewhat artificial devices of setting registers with strings of
numbers. Syntactically, lout is dead easy to change. The only
difficulty is in knowing where to put the changes. You are told this
in the documentation.
<p>
Let me give an example. Suppose you want to change the doc
style so that it more closely imitates the output of troff's mm
macros. (Not that I recommend doing this!) In particular you want to
set the default font size to ten points, you want to make block style
paragraphs the default style, and you want the headings to be in
italics. Assume that you wish to do this locally rather than
system-wide. Then you have to make yourself a new style file to change
the paragraph style. First copy LIBDIR/include/doc to the
working directory call it troffdoc. Now open up the file with
a text editor. You will see the following near the top of the file.
<pre>
@Use { @DocumentLayout
# @InitialFont { Times Base 12p } # initial font
# @InitialBreak { adjust 1.20fx hyphen } # initial break
# @InitialSpace { lout }# initial space style
# @InitialLanguage { English } # initial language
# @InitialColour { black } # initial colour
# @OptimizePages { No } # optimize page breaks?
# @HeadingFont { Bold } # font for @Heading
# @ParaGap { 1.30vx } # gap between paragraphs
# @ParaIndent { 2.00f } # first-line indent for @PP
# @DisplayGap { 1.00v } # gap above, below displays
# @DisplayIndent { 2.00f } # @IndentedDisplay indent
# @DefaultIndent { 0.5rt } # @Display indent
........
</PRE>
This is a list of the parameters that can be set (the list is
longer. I have included roughly what I need for this example.) Notice
that the settings are commented out. First uncomment the line with
<tt>@InitialFont</tt> and change the <tt>12p</tt> to <tt>10p</tt>. Now
you have your ten-point default. Now go down to the line
<tt>@ParaIndent</tt>. Uncomment it and change the <tt>2.00f</tt> to
<tt>0f</tt>. Now you have no indentation for paragraphs. The vertical
space between paragraphs is pretty good as it stands so leave
<tt>@ParaGap</tt> as it is. Now we want to take care of the font for
the headings. Right above the <tt>ParaGap</tt> line is one with
<tt>@HeadingFont</tt>. Uncomment this and change <tt>Bold</tt> to
<tt>Slope.</tt> Now you are there. Save the file. and change the top
line of your source from <tt>@SysInclude{doc}</tt> to
<tt>@Include{troffdoc}</tt>. Now you have it. If you want to make it
system wide, and you have root privileges you can put it in
LIBDIR/include or if you wish to be dictatorial, modify
doc itself.
<p>
All three formatters offer facilities for making cross references and
a table of contents. LaTeX and troff offer an interface with
programs that will automatically produce bibliographies from databases
and indexes. <B>lout</B> is unique in offering these two built
in. Given that you want these features, lout is the easiest of
the three formatters to install, maintain and use. My installation
takes up 4.3Mb and this includes the <B>teq</B> package that I
recommended and a package for producing bar codes. This makes it a
pretty modest formatter.
<p>
I spoke about the <I>ensemble</I> of the other two programs. There is
not much to say about that for lout. Everything is built in and
is accomplished by using flags on the command line or by requesting
that the relevant files be read in. Each setup file has a list of
parameters at its beginning. You can change them, or you can change
this parameter in your source file. For example, I made some changes
to how the section headers would look in both LaTeX and
troff. To change spacing above and below the header in
lout I would simply put <tt>@DisplayGap{.75v}</tt> at the beginning
of my file. This would change the default spacing of one space to
three-quarters of a space and make the document more compact. This is
considerably simpler than what must be done for LaTeX. It is easier to
remember than the somewhat artificial method in troff of setting
a string register.
<p>
One problem with TeX has always been that it takes an expert to
manage. Unfortunately most system administrators are not interested in
test formatting and so in many sites an "off-the-shelf" version
is installed and the users accept the defaults or learn to change them
themselves. On the other hand, a system administrator who knows
nothing about lout could change the relevant line in the
LIBDIR/include/doc file to read as above and the change will
be universal. Ordinary users can make their private default by writing
out the parameters to be changed in a file on the path specified by
the <tt>-I</tt> flag described earlier. In extreme cases they can even
copy the default setup file to such a place and modify any or all the
parameters. With a modified doc in a private directory
<tt>@Include{doc}</tt> is placed at the top of the document instead of
<tt>@SysInclude{doc}</tt>.
<p>
I mentioned earlier that lout produces a Postscript file where
the other two produce device independent ones. This means that the
lout language can offer equivalents of all of the Postscript
geometric and color commands. Since these commands are programmed into
the formatter, it puts the objects created by them in a first class
box. This is as opposed to Tex and troff which allow Postscript
commands to be sent to a suitable driver while ignoring them during
the creation of the device independent file. In this case it is up to
you to provide a second class box to make room for objects created
and/or transformed by the Postscript commands. The price you pay for
this is a loss of device independence. <B>ghostscript</B> fixes a lot
of this problem (see the section on Postscript) but if you have a high
quality non-postscript laser printer with resident fonts, you have to
abandon those fonts and get new ones. Your gain is the added
flexibility of Postscript though.
<p>
The new version of LaTeX, LaTeX2[epsilon], has a package called
<B>graphics</B> that extends the markup language to allow for
rotation and scaling. There is another package called <B>color</B>
that extends the language for employing color. Packages come out as
the need for them becomes clear. For example there is one called
<B>fancybox</B> that makes shadow boxes. However, graphics
and color will only work with certain Postscript drivers at
present. Thus you have to give up device independence when you use
them. (I can't give you the complete collection of packages needed to
match lout's capabilities. The documentation with some of them
is scant. Keep in mind, however, that LaTeX2[epsilon] is in an
experimental version. LaTeX3 when it comes out might have a complete
package for graphic which can then be documented in the "standard
literature".)
<p>
I have been assuming that documents consist mainly of text with
incidental graphics inserted. There are other kinds of documents, such
as advertising layouts, that should be looked at as graphics with
incidental text inserted. For the reasons given in the last paragraph,
lout has to be considered as the best tool for this. Closely
related to this is the option of producing <B>Encapsulated
Postscript</B> (EPS) which produces graphics files meant to be included
inside a larger document. This option is invoked with the
<tt>-EPS</tt> flag.
<p>
<B>lout</B> also offers the option of producing ASCII output. In order
to do this you use the <tt>-P</tt> flag on the command line
and change whichever setup file you are using to one with an "f"
attached to its name. (So you would have <tt>@SysInclude{docf}</tt> in
place of line (1) of sample.lt. This will not be necessary in the next
version, doc will work with both outputs. If one is to judge from the
text newsgroups, being able to produce both ASCII for on-line
documentation, and high quality hard copy with the same source file is
a very desirable feature. It is one shared by troff but not by
LaTeX.
<p>
There is a trend to use fonts other than the standard Adobe fonts
provided with Postscript printers. Traditional fonts like Garamond and
various exotic fonts for special purposes can be bought for a
reasonable price nowadays. <B>lout</B> is the easiest formatter in
which to install new fonts and I will close this lout specific
section by outlining how to do this.
<p>
First of all, with your new fonts you should have a set of outline
(glyph) files. They have the extension .pfa or .pfb
and they are of no concern to lout. They are installed in your
postscript printer or in ghostscript. See the earlier section on
Postscript for instructions on how to do the latter.
<p>
Secondly you should have a set of metric files. These are what
lout wants to work with. These files have the extension
.afm for "Adobe font metrics". <B>lout</B> uses these
without modifications.
<p>
I will continue to use LIBDIR to denote the directory in
which the lout library has been installed
(/usr/local/lib/lout by default.) There is a directory called
LIBDIR/font and that is where the font metric files are
placed. You can give them any name you like that doesn't coincide with
the ones already there. The default fonts have names in mostly in
capitals without an extension. They are abbreviations that describe the
font. For example Times Roman is denoted by <tt>TI-Rm</tt> and
Times Italic is denoted by <tt>TI-It</tt>. To make things more
concrete let me use the same Charter fonts that I installed in
<I>ghostscript</I> earlier as a running example.
<p>
There are four files for the Charter fonts (at least in my version):
bchr.afm, bchri.afm, bchb.afm,
bchbi.afm. (By the way, the initial "b" in the name is
for <B>Bitstream</B> the producers of the font.) These are the metrics
for Roman, Italics, Bold and Bold Italics respectively. I have decided
to call them CH-R, CH-I, CH-B, and
CH-BI in the lout installation. I copy the files into
LIBDIR/font with their new names. For example cp bchr.afm
LIBDIR/font/CH-R. If you are sure you won't need them for
something else, such as installing them in TeX or <B>groff</B> then you
can move them instead of copying them. They are now installed and the
next step is to tell lout about them.
<p>
Change to the directory LIBDIR/include and open the file
fontdefs with a text editor. This file has long lines that
should not be broken so make sure your editor is not set to
automatically break lines. The file will be hard to read with a
standard eighty column screen, but there is not much to it. If you are
using X you can elongate the window.
<p>
The general format of the file is all in one line:
<pre>
fontdef &lt;lout family&gt; &lt;lout face&gt; {&ltzPostscript&gt; &lt;font-metric file&gt; &lt;character map file&gt; &lt;Recode?&gt;}
</PRE>
<tt>fontdef</tt> is the command that tells lout that what
follows is a font definition. You will put that on each line of the as
the first entry. It is the only command you need know about to install
a font. <tt>&lt;lout family&gt;</tt> is the family name with which
you will refer to the general family. You can choose this. I choose
the name Charter. <tt>&lt;lout face&gt;</tt> is the style of
face. The default body face (often called Roman) is labeled
Base, Italics is labeled Slope, Boldface is labeled
Bold and Bold Italics is labeled BoldSlope. In
theory you can change these, but I don't recommend it as if you do
some of the built-in default font selections of lout won't work
properly. You will have to be prepared to give every font change
command in its full form. <tt>&lt;Postscript&gt;</tt> is the official
Postscript name. You obtain that from the .afm file as I
described in the Postscript section. However note that it is written
differently in this file than it is in the Fontmap file in
that it is missing a leading "/". That slash is part of
the ghostscript language and is not used by lout. The
Postscript name includes the family and the face.
<tt>&lt;font-metric file&gt;</tt> is the name of the file you put in
LIBDIR/font containing the font metrics.
<tt>&lt;character map file&gt;</tt> is the file that tells lout which place on
the font table each character is to be found. For any font consisting
of standard alphabetical characters (as opposed to special symbols)
you will use LtLatin1.LCM. The various mapping files are to
be found in LIBDIR/maps, but you needn't be bothered with
them unless you want to do something special, like install a new
symbol font. Most of the font families don't offer a separate symbol
font anyway but rely upon the standard Postscript one. This is what
lout assumes. The last entry <tt>&lt;Recode?&gt;</tt> consists of the
word <tt>Recode</tt> or the word <tt>NoRecode</tt>. This is to tell
lout whether to use the character mapping. Again, unless you are
planning to do something unusual, you should choose Recode.
<p>
Next, where to put the entries for your new font. The existing
fontdefs file starts out with all of the font definitions
that come with lout. Put you new ones right after them. So
scroll down the file until you see the last line starting with
fontdef and put yours right underneath. Comments are denoted
by # at the beginning of the line so you complete
entry can look like:
<pre>
### Added by me 1 December 1996
fontdef Charter Base {CharterBT-Roman CH-R LtLatin1.LCM Recode }
fontdef Charter Slope {CharterBT-Italic CH-I LtLatin1.LCM Recode }
fontdef Charter Bold {CharterBT-Bold CH-B LtLatin1.LCM Recode }
fontdef Charter BoldSlope {CharterBT-BoldItalic CH-BI LtLatin1.LCM Recode }
</PRE>
That is all there is to it. Your fonts are now installed. Now if you
begin your document with
<pre>
@SysInclude{doc}
@Document
@InitialFont{Charter Base 12p}
//
@Text @Begin
</PRE>
it will be typeset in the Charter font. The command <tt>@I</tt> will
call for Charter Italics, and so on. If you call for special symbols
they will come from the symbol font which is installed by default in
lout.
<p>
Note that you are free to assign lout font families to any set
of font files as with the virtual font construction in Tex. That is
you can take Base from the font foo with official
Postscript name foo-Roman and Slope from the font
bar with official Postscript name bar-Italic. If you
call this new font Newfoo, your entry in the fontdefs file
will begin like this
<pre>
fontdef Newfoo Base {foo-Roman ...
fontdef Newfoo Slope {bar-Italic ...
</PRE>
This is handy because some font families have a face missing. You just
have to find one that blends in with the existing faces. This is what
is done by typesetters and you can find books that tell you which ones
blend with which.
<p>
All that I have said about installing fonts assume that the fonts are
encoded with eight bits. This means that eight bit words are used to
describe each character in the font, allowing a font to contain 256
characters. If you use TeX you might be aware that the original
version only used seven bit words to name the characters in a
font. This was changed in later versions, but the Computer Modern
fonts weren't recoded for this change. The result is that each
standard TeX font can only have 128 characters. What gets left out are
the European special characters that are not used in English (various
accents, crossed out els, etc). Instead they are formed by
digraphs--the overstriking of two different characters. <B>lout</B>
assumes that these extra characters are available and it is not set up
to form digraphs[footnote 9. Of course macros can be written to form
them.]. Other symbols that are on the ordinary alphabetical fonts in
Postscript are to be found on the Computer Modern symbol font and code
has to be written to point lout in the right direction. Thus if
you want to install a Postscript version of the Computer Modern fonts
in lout, such as the free <B>BaKoMa</B> ones, you have to do a
lot more work. There is an eight bit encoding of the Computer Modern
font now, sometimes known as the "Cork encoding", and when a
Postscript version of these comes out, it will be easy to install
Computer Modern in lout.
<p>
<H4>Summary</H4>
<p>
In a nutshell, lout offers all of the capabilities of LaTeX
requiring considerably less resources. It doesn't do quite as good a
job putting together the fragments that make up large delimiters,
large square root signs, and the like, but it still does a good
job. The difference is small enough so that I wouldn't use it as a
criterion for choosing one above the other. All three of the
formatters I described do a good job with bread and butter
typesetting, that is line and paragraph breaking and and sane
hyphenation. I wouldn't make my choice on this basis either.
<p>
<B>lout</B> seems to run slower than LaTeX for an equivalent job and
requires more passes to resolve references that are written to an
extra file, such as cross-references. If you have a slow machine, or
do huge documents with a lot of cross-references, tables of contents,
and so on, and if time is a factor, then you might find lout to
slow for you. On the other hand, lout allocates memory
dynamically and so you won't run out of memory with a complex
document as you can with LaTeX.
<p>
Like LaTeX, lout offers logical markup and it is far easier to
customize the layout files than it is to customize LaTeX style
files. On the other hand, TeX offers a more convenient macro
interface. You can write them anywhere in the document or in a
separate file to be input at any point of the document, whereas with
lout you have to write some in a separate file which is kept in
the working directory. (There do seem to be comands that change the
scoping rules, but they are not well documented.) This is hardly a
disadvantage if you use one directory per document, or if you group
small documents that need the same macros in the same directory, but
if you keep several documents in the same directory, each needing
macros with the same name, but with different actions, then you will
have to do some editing of the layout file. It also makes it difficult
to send a document in a single file if it uses user-defined
macros. Many TeX-perts feel that it is a bad idea to put all of the
macros in one file anyway; for the same reason it is not a good idea
to have all of the source in one file for a large programming
project. In the case of TeX, there is enough difference in different
installations so that often a large document produced in one site has
to be mildly edited before it is processsed or printed at another. It
is far easier to find these problems if the document is logically
divided into modules. (I tend to <B>tar</B>, <B>gzip</B> and then
<B>uuencode</B> my documents before sending them by email. They pass
safely through the most primitive mailing routes this way. It does
depend upon the person on the other end having versions of
<B>uudecode</B>, <B>gunzip</B> and <B>tar</B>, but there are versions of
these for most operating systems.)
<p>
Of the three formatters that I described, "Barefoot" LaTeX is
the weakest for drawing facilities lout is the strongest. LaTeX
with suitable packages and lout as it is produce geometric
transformations of objects in first-class boxes, lout is the
more versatile. The gpic package that comes with groff
falls down in that department, but it is by far the most user-friendly
package for drawing. It can be used to produce pictures that can be
imported into LaTeX with the <tt>-t</tt> option which turns it into a
GNU version of tpic (as usual with more features than the
original.) Pictures made with gpic can be saved as Postscript
files and easily imported into lout.
<p>
You have to buy troff and LaTeX documentation. There are
standard books for LaTeX which I mentioned earlier. The other book
that should be on your shelf if you use LaTeX is "The TeXbook" by
Donald Knuth, also published by Addison Wesley. A new version of
LaTeX2[epsilon] is issued every six months so there is no chance that
any book can keep up-to-date. New packages usually come with
documentation, but sometimes it is pretty scant and requires
considerable knowledge of TeX to decipher. Problems and solutions are
usually posted in the comp.text.tex newsgroup. Good books on
troff, and especially the <B>mm</B> macros are getting hard to
find. My favorite, which is out of print at present, is "UNIX Text
Processing" by Dougherty and O'Reilly, published by Hayden. O'Reilly
and Associates also publish the Berkeley 4.4BSD User's Supplementary
Documents which contains documentation on troff but doesn't
discuss <B>pic</B> or the mm macros. There is no newsgroup for
troff specifically, but it problems and solutions are often
posted to the comp.text group.
<p>
<B>lout</B> comes with its own documentation. The user's guide is a
book and compares with the textbooks for the other processors. If you
want to go deeper into its internal workings there is the expert's
guide. There are examples in both of them. I have bound the user's
guide in two parts. The first comprises chapters 1-5 which contains
the document formatting information and the second comprises chapters
6-11 which contains information on the individual packages. You
won't see textbooks on lout on the shelves of bookstores and so
if don't like the documentation provided, you are stuck. There is
sometimes discussion on comp.text about lout and there
is a mailing list. To subscribe send an email to
lout-request@nlif.spb.su with subscribe in the
Subject field.
<p>
I haven't said much about recovery from error. All of the formatters
are pretty cryptic in this department. <B>lout</B> and troff are
both the strong silent type that only say something when they need
to. If lout runs into an error it will give you the line and the
relative place on the line where it is detected. Raw troff gives
nothing away except that there is an error. It does provide macro
writers with a mechanism for error reporting and the mm
package is pretty informative. TeX gives you a running commentary of
what pages are being output, and what files are being read in. When it
comes upon an error it gives tells you in what file and in what line
of the file the error was found. It also opens an interactive window
and offers several options for handling the error. I mentioned some of
the more interesting ones earlier. This constant activity on the
screen while TeX is running might make it appear to finish faster than
lout which leaves you staring at a blank screen until something
goes wrong. Just as you have to learn how to write markup, you must
learn how to interpret error messages. I know from experience that you
get better with experience.
<p>
There are what I would call external disadvantages to using
lout. By that I mean those that are caused by the fact that it
is relatively new and not used by a large number of people. This
means, first of all, that you won't find, for instance a "lout
mode" written for the emacs editor. Although the drawing facilities
that come with lout are pretty extensive, they need some
"sugar coating". For example, it is a nuisance to draw
commutative diagrams in the present language[footnote 9, I assume from
browsing the site ftp://ftp.cs.su.oz.au/jeff/lout that there
is a commutative diagrams package in the offing.]. I would like a more
user friendly way of putting named blocks of graphics together. (See
Chapter 9 of the User's guide for how it needs be done at the
present.)
<p>
The other external disadvantage is that publishers are most likely not
equipped to handle lout source code. For camera-ready documents
this is no problem, but if the camera-ready source is to be produced
by the publisher, then the entire document will have to be
re-keyed. Similarly if you want to email a source file to a colleague,
he or she will have to have lout installed to read it.
<p>
To some extent these are problems that can fix themselves with
time. For all we know somebody might be writing an <B>Emacs</B> mode for
lout at this very moment. As far as publishers are concerned;
over the years I have heard bitter complaints from fellow
mathematicians that so-and-so publisher won't accept TeX document with
such-and-such macro packages. The situation changes as the package
gets more popular and proves its usefulness.
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, Murray Adelman <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
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</H4>
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<!--===================================================================-->
<center><h1>Using the Flame Plug-In for Backgrounds</h1></center>
<center>
<h4>By <a href="mailto: layers@marktwain.net">Larry Ayers</a></h4>
</center>
<hr>
<center><h3>Introduction</h3></center>
<p>Lately I've happened upon a technique for making unobtrusive but pleasing
screen backgrounds using Scott Draves' <b>Flame</b> plug-in for the Gimp.
These backgrounds possess characteristics common to many fractal images,
especially those created with some variation of the Iterated Function Systems
(IFS) algorithms. They aren't symmetrical, but there is some mysterious
organizing principle which gives them a quasi-organic appearance, though they
don't really resemble any organic forms (on this planet, at least!). They
also can be reminiscent of microphotographs or scanning-electron-microscope
photographs.
<p>Before I outline the technique I've been using, here are some
examples of these tile-able images:<br>
<p>
<center><img alt="flame background #1" src="./gx/ayers/flame1.gif">
<img alt="flame background #2" src="./gx/ayers/flame2.gif">
</center>
<center><img alt="flame background #3" src="./gx/ayers/flame4.gif">
</center>
<hr>
<p>These images were originally 512x512 pixels but they have been reduced to
half size for faster loading. They are usable as backgrounds at this size but
are more detailed and interesting in the original size. I've also converted
them to GIF format (from JPEG) and reduced their color-usage. This has
degraded the images somewhat. Generate one from scratch to see the finely
detailed tracery which Flame can render.
<hr>
<center><h3>Procedure</h3></center>
<p>Before starting the Flame plug-in (in the <i>Filters-&gt;Render</i>
sub-menu) it's a good idea to first create a new blank image. It will appear
with the default white background; flood-filling it first with a background
color or pattern saves a lot of time later. After the Flame pattern has been
applied to the image it can be difficult to alter the background without
affecting the fractal portion of the image. Two layers could be used instead,
but this is intended to be a quick procedure. Any background image will
eventually become nearly unnoticeable after a while, so it's handy to have a
fast means of creating new and interesting ones.
<p>Once your background is satisfactory, select the Flame plug-in (a
screenshot of an earlier version of the interface is in one of my articles in
LG #24, <i>Updates and Correspondence </i>). The main window will display a
thumbnail image of a pattern rendered with random parameters and one of
several built-in color-maps. Controls in the window allow tweaking
several variables, such as position, zoom-level, and color-map. Click on the
<i>Shape Edit</i> button and a new window will appear with nine thumbnail
images, the center one being the original and the others variants of it.
Click on any of these (with the left mouse button) and it will become a parent
to eight new versions. There are several different types of mutations (such
as spherical, sinusoidal, or horseshoe) available from the <i>Variations</i>
menu. Though not immediately evident, clicking the right mouse button on any
of the nine selects it and it will take the place of the original image in the
main window when the "Ok" button is clicked, dismissing the Edit window.
<p>Make any adjustments in the main window, perhaps even returning to the Edit
window if necessary, before clicking the main window's "Ok" button; once this
is clicked there is no going back without starting all over. Though all of
Flame's thumbnails are displayed with a black background, the only part of the
rendering which is applied to the empty destination image is the foreground,
thus the need for the preparatory background filling described above.
<p>The <b>Make Seamless</b> plug-in (in the <i>Filters-&gt;Map</i> menu) isn't
suited for every sort of image, but these Flame-generated images usually tile
well. After saving the image in the format of your choice, try it out with
<kbd>xv -root -quit [filename]</kbd> on an empty desktop. Though there are
several utilities available which will load a random background image when X
starts up, my favorite set-up is to have a simple image or background color
load in my <kbd>.xinitrc</kbd>, then set up a window-manager sub-menu with a
few favorite tile-able images. Here is an example from my
<kbd>.fvwm2rc</kbd>:<br>
<pre><kbd>
AddToMenu Backgrounds "Backgrounds" Title
+ "Flame1" Exec exec xv -root -quit ~/.backgrounds/ft1.jpg
+ "Flame2" Exec exec xv -root -quit ~/.backgrounds/flt5.jpg
+ "Bluetile" Exec exec xv -root -quit ~/.backgrounds/bluetile.jpg
+ "Marble" Exec exec xv -root -quit ~/.backgrounds/marb2.jpg
</kbd></pre>
<p>Have fun!
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, Larry Ayers <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
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<center><h1>The Maxwell Word-Processor</h1></center>
<center>
<h4>By <a href="mailto: layers@marktwain.net">Larry Ayers</a></h4>
</center>
<hr>
<p>An interesting announcement was posted in late February to the
comp.os.linux.announce newsgroup concerning the free availability of a new
word-processor for Linux. It seems that the Maxwell word-processor had been
developed by a British software company, Tangent Data Limited, with the
intention of selling it as a commercial product, but for some reason the
project was scrapped and the company was wound up. The three programmers
involved (two of whom were partners in the firm) decided to release on the web
a statically-linked Motif binary package.
<p>I didn't really need a word-processor, but curiosity got the better of me,
especially since it was just a one-and-one-half megabyte download. It wasn't
hard to install (just unpack into /usr/local) but when I started it from an
rxvt window, many seconds went by, with no disk activity. Evidently the
license daemon is still automatically summoned, but since there isn't any
licensing to do it gets confused and hangs for a while before reluctantly
allowing the program to start. Finally a small control window appeared with a
button on it inviting me to "open a document window"; I tried, and the window
would appear for a fraction of a second before dying of terminal segmentation
fault. Oh, well...off to /dev/null with that one, but before consigning the
directory to oblivion, I noted the e-mail address to which comments and
bug-reports should be directed, and pasted the error-messages into an e-mail
message. Within a couple of hours I had a reply from Tom Newton, one of the
developers, in which he stated that they had received other, similar reports
from users with 16 bpp displays (which is what I use). That evening I
received another message, this one bcc-ed to what must have been quite a few
other Linux users who had written. It seems that so many people had tried to
download the Maxwell archive that the ISP was swamped, and requested that the
file be moved elsewhere. Before uploading it to Sunsite's incoming directory,
the developers fixed the 16-bpp bug. The message also hinted that the
application might end up GPL-ed, with full source available.
<p>So I tried it again, and this time it would successfully start up. The
document window is a typical Motif word-processor interface, with the usual
menu- and button- bars. Here's a screenshot:<br>
<p>
<center>
<img alt="Maxwell Document Window" src="./gx/ayers/max1.gif">
</center>
<hr>
<center><h3>Features and Limitations</h3></center>
<p>I use mostly free software, and one annoying trait I've noticed in many
commercial applications for Linux is the neglect of perfectly serviceable
utilities which are found on just about any Linux system. As an example, the
ispell program is an efficient and dependable spell-checker, easily
incorporated into other programs. Nonetheless many word-processors include
their own spell-checking dictionaries and routines, one reason for their bulk.
<p>Looking over the Maxwell files, I was interested to see that in the binary
directory there are only two real files, the main executable and the license
manager. The remainder of the files are symbolic links to <em>file</em>,
<em>grep</em>, <em>ghostscript</em>, <em>lpr</em>, and <em>ispell</em>.
Evidently the developers are familiar with Linux and saw no reason to
re-invent several wheels. I imagine the savings in work was a factor as well.
<p>The fonts are also represented by symlinks to a few of the fonts in the
/usr/X11R6/lib/X11/fonts/type1 directory, with each one accompanied by an .mfm
file, which stands for Maxwell Font Metrics. These files are automatically
generated by Maxwell when it starts up and finds new fonts or symlinks
installed. Adding new fonts isn't difficult (thanks to Tom Newton for this
information!); just symlink them from your usual font directory (often
<kbd>/usr/X11R6/lib/X11/fonts</kbd>) to
<kbd>/usr/local/maxwell/fonts/Type1</kbd> and add entries to the
<i>fonts.scale</i> and <i>fonts.dir</i> files in the same directory (these are
installed as symlinks, but don't have to be).
<p>Symlinks may have to be altered in order to enable the spellchecker. A
subdirectory, <kbd>/usr/local/maxwell/dict</kbd>, should be created if it
doesn't already exist, and the various <kbd>*.hash</kbd> files which <b>ispell
</b> uses should be symlinked there; these are often found in
<kbd>/usr/lib/ispell</kbd>. When this is correctly done a typical spell-check
window can be summoned.
<p>Maxwell saves files in its own binary format which is translated into
Postscript before being sent to the printer. I don't have a printer which
understands Postscript, but any print-filter which will call ghostscript with
the necessary switches should work; it does for me. A disadvantage to this
approach is that print quality will be dependent upon how well ghostscript
supports your printer. Rich Text Format (RTF) is also supported and these
files can be successfully loaded by WordPerfect. There seems to be quite a
clamor in the Linux newsgroups for a word-processor which can load and save
MS-Word format files, but Maxwell lacks this feature. The MS word-processors
do support RTF, so there is some potential for file interchange between MS
apps and Maxwell.
<p>At first I thought Maxwell used its own font-rendering routines rather than
the native X services, as scalable fonts are displayed on the screen free of
the jagginess X applications usually suffer from when non-bitmap fonts are
rendered. The rendering is better than this, but not quite as anti-aliased as
the Gimp's or Ghostscript's output. Tom Newton (in an e-mail message) stated
that Maxwell uses native X calls but small chunks of text are rendered
separately before the position of the next chunk is calculated.
<p>This is a worthwhile and notable feature; it has no effect on print quality
but makes for more readable text on-screen when using different font sizes.
<p>Some of the features, such as the table-creation facility and graphics
inclusion, need more work. Attempting to include a graphics file in a
document will cause Maxwell to crash if it is running on a 16 bpp
display. Tables can be included, but though the fields dynamically resize
themselves I didn't find any way to add padding or borders around fields.
<p>Basic page and character layout is handled much as in other
word-processors, with dialog-windows as well as menus and button-bars. In
short, most standard word-processor functions work well, something
which can't be said for the various free word-processor projects I've tried,
many of which have been seemingly abandoned. All but LyX, that is, but LyX is
<i>sui generis</i>.
<center><h3>Conclusion</h3></center>
<p>There has been a remarkable lack of public comment from the Linux community
concerning Maxwell, considering how often the plea for a free word-processor
is reiterated. I suspect that many people downloaded it, found that it
wouldn't (in the initial version) run on a 16 bpp display, and discarded it.
As I stated above, this has been remedied, and the current version is well
worth a try. If the source was released under the GPL I'm sure interest would
pick up and further enhancements would begin to appear.
<p>After much of this article was written a third release (version
0.5.2) was uploaded to
<a href="ftp://sunsite.unc.edu/pub/Linux/Incoming">Sunsite</a>. A few bugs
have been fixed, and the annoying and time-consuming license manager has been
removed, so the start-up is much quicker. According to Tom Newton, who has
been putting together these releases, this will be the final binary version;
if the source isn't released Maxwell will probably fade into obscurity.
<p>So what will Maxwell's eventual fate be? The two former partners in
Tangent Data own the rights and haven't decided what to do with it. A
possibility of GPL status has been mentioned which would be interesting and
useful to us all. One possibility would be to release source for the current
build and then sell plug-ins or modules which would add features such as
additional file-exchange filters. Support could be a fee-based service as
well. This approach is being developed for the Gimp by the new WilberWorks
company.
<p>Even if the source isn't made available Maxwell is usable in its current
state for basic word-processing, helping fill the gulf which currently exists
between text editors and the large and feature-laden applications such as
StarOffice, Applix, and WordPerfect.
<!--===================================================================-->
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<center><H5>Copyright &copy; 1998, Larry Ayers <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
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<center><img alt="WordNet logo" src="./gx/ayers/wn.gif"></center>
<hr>
<center><h1>WordNet: A Fast and Flexible Word Database</h1></center>
<center>
<h4>By <a href="mailto: layers@marktwain.net">Larry Ayers</a></h4>
</center>
<hr>
<center><h3>Introduction</h3></center>
<p>There have been times when I've wished I had dictionary program with a
Linux interface. One of my favorite print dictionaries is the American
Heritage Dictionary, which I've used and appreciated for many years.
<a href="http://www.dux.com/ahdictux.html">Dux Software</a>
has been offering a Linux version of their computer interface to the
dictionary (combined with a thesaurus) for some time now, but I was deterred
by the $49.95 price-tag, considering the existence of a perfectly usable print
copy of the book, sitting on a shelf not six feet from where I'm typing this.
But there are powers which the computer-based dictionary possesses which can
be quite useful. A computer excels at searching for information in a
database, and combined with the power of regular expressions a digital
dictionary has significant advantages.
<p>The only free digital dictionary I've come across was an old edition of
Webster's, available from Project Gutenberg in the form of two large text
files. These could be searched for a word with <em>grep</em>, but I was
looking for something with an X interface; <em>grep</em> would also find
instances of words used within a definition, which would clutter up the
output. Of course there are on-line WWW dictionaries, which are fine for
people who are on-line most of the time. Users accessing the net via a
dial-up connection with an ISP are unlikely to be online while writing text
for which a dictionary would be needful. I happened across a usenet posting
recently which led me to to this <a
href="http://www.cogsci.princeton.edu/~wn/">site</a>, and before long I was
downloading a 13 mb. archive containing a dictionary/thesaurus called WordNet.
<center><h3>WordNet Basics</h3></center>
<p>The usenet announcement of the most recent WordNet release contained a
good description of the package:<br>
<blockquote>
WordNet is a powerful lexical reference system that combines aspects of
dictionaries and thesauri with current psycholinguistic theories of human
lexical memory. It is produced by the Cognitive Science Laboratory at
Princeton University, under the direction of Professor George Miller. In
WordNet, words are defined and grouped into various related sets of
synonyms. Not only is the system valuable to the casual user as a powerful
thesaurus and dictionary, but also to the researcher as one of the few
freely available, lexical databases. WordNet is available via an on-line
interface and also as easy-to-compile C source code for Unix.
</blockquote>
<p>WordNet consists of interlinked databases of words, synonyms, antonyms,
and usage examples. In the best unix tradition, this data can be manually
accessed via the command-line. This makes it relatively easy to create
script-based interfaces which can simplify the usage of the tool and provide a
windowed, menu-driven front-end. The distribution contains the source code
for the basic utilities and a Tcl/Tk interface, as well as statically linked
binaries and the database files.
<p>One difference between WordNet and a traditional dictionary is the lack of
etymologies, a feature typically used much less often than the simple display
of meaning and syntax. The inclusion of thesaurus-like features more than
makes up for this lack.
<p>A full WordNet installation, consisting of the data-files and the
command-line and statically-linked executables, occupies more than thirty
megabytes of disk space. This is an ideal job for the
<a href="http://www.netspace.net.au/~reiter/e2compr">e2compr</a>
kernel-level transparent file-compression system; I compressed the database
directory and reduced it from thirty megabytes to eleven and one-half, with no
noticeable speed penalty. See LG #18 (June 1997) for an introduction to
<b>e2compr</b>.
<center><h3>Examples</h3></center>
<p>Here are a few examples of command-line use of WordNet:<br>
<p><kbd><pre>%->wn gazette -over
Overview of noun gazette
The noun gazette has 1 sense (no senses from tagged texts)
1. gazette -- (a newspaper)
Overview of verb gazette
The verb gazette has 1 sense (no senses from tagged texts)
1. gazette -- (publish in a gazette)</pre></kbd>
<p><b>wn</b> is the command-line search tool, and the switch <b>-over</b>
shows an overview of meaning and parts of speech the word can have.
<p><kbd><pre>%->wn gaz -grepn
Grep of noun gaz
gaza strip
gazania
gazania rigens
gaze
gazebo
gazella
gazella subgutturosa
gazella thomsoni
gazelle
gazelle hound
gazette
gazetteer
</pre></kbd>
<p>The switch <b>-grepn</b> searches the noun database for any noun containing
the string <i>gaz</i>; there are variants of this switch: <b>-grepv</b>,
<b>-grepa</b>, and <b>-grepr</b>, which respectively search for verbs,
adjectives, and adverbs. The various <b>grep</b> switches can be used to
determine the correct spelling of a word when you are certain of the spelling
of only a syllable or portion of the word.
<p><pre><kbd>
%->wn quell -framv
Sample Sentences of verb quell
2 senses of quell
Sense 1
squelch, quell
*> Somebody ----s something
Sense 2
quell, stay, appease
*> Something ----s
*> Something ----s somebody
</kbd></pre>
<p>The <b>-framv</b> switch used above shows how the word is used in
sentences.
<p><pre><kbd>
%->wn quell -simsv
Synonyms (Grouped by Similarity of Meaning) of verb quell
Sense 1
squelch, quell
=> suppress, stamp down, inhibit, subdue, conquer, curb
--------------
Sense 2
quell, stay, appease
=> meet, satisfy, fill, fulfill
--------------
</kbd></pre>
<p>The <b>-simsv</b> switch shows verb synonyms, and a variant <b>-simsn</b>
lists the noun synonyms of a word.There are a plethora of other <b>wn</b>
switches for finding antonyms, homonyms, and several other more obscure
lexical types, many of which have easier-to-use equivalents in the Tcl/Tk
windowed interface, <b>wnb</b>, which stands for WordNet Browser.
<center><h3>Using The Browser</h3></center>
<p>Here are screenshots of the browser window and a subsidiary sub-string
window, which takes the place of the <b>-grep[nvar]</b> switches used with
<b>wn</b>.<br>
<p><img alt="Main wnb window" src="./gx/ayers/wnb.gif">
<p><img alt="Substring (grep) window" src="./gx/ayers/grep.gif">
<p>This is a convenient and easy-to-use interface, with all functions
available from the menus. The output, though, isn't wrapped to fit the
screen, so to avoid having to scroll sideways to see it all the window should
be resized so that it is wider horizontally. You might be tempted (as I was)
to try compiling the source code, so that the <b>wnb</b> executable will use
your own Tcl/Tk libraries rather than the bulky statically-linked
libraries compiled into the supplied executable file. Unless you happen to
have the particular patch-level of Tcl-7.6 and Tk-4.2 which the source needs,
it probably won't compile (at least it wouldn't for me). If the <b>wnb</b>
interface was just a Tk script, it wouldn't be a big job to modify it so that
it uses a particular Tcl/Tk installation, but <b>wnb</b> has its own
specialized wish interpreter, which complicates updating the source for a
newer version of Tcl/Tk. Since the supplied Tcl/Tk interface is just a
convenient way of viewing the output from <b>wn</b>, perhaps a GTK, Qt, or
Emacs-LISP interface could be coded; this would make a welcome addition to the
KDE and GNOME projects. I've found that a handy way to run <b>wn</b> is in a
separate wide-and-short XEmacs shell-buffer frame.
<center><h3>Documentation and License Issues</h3></center>
<p>The documentation supplied with the distribution is complete and clearly
written; it's all an end-user should need. HTML, Postscript, and man-page
formats are included to cater to various reading preferences. If you are
curious about the psycholinguistic theoretical underpinnings of the project, a
Postscript file (5papers.ps) is available from the web-site.
<p>While writing this article I happened to be paging through the introductory
essays in the American Heritage dictionary. One of these essays was written
by one of the linguists responsible for the work which inspired the WordNet
project, Henry Kucera. It's called <cite>Computers in Language Analysis and
Lexicography</cite>, and it's a more general (though dated) overview of
psycholinguistics than the above mentioned collection of papers. If you're
wondering just what in the world the "Browne Corpus" is (mentioned on the
WordNet web-site), this essay explains it clearly.
<p>WordNet isn't licensed under the GPL, but the license isn't very
restrictive at all. The utilities and programs needed to create the word
databases are not distributed, but the supplied files are sufficient for most
needs.
<center><h3>FTP Sites</h3></center>
<p>WordNet can be obtained from its home
<a href="ftp://ftp.cogsci.princeton.edu/pub/wordnet">site</a>, but this is a
really slow site, and I had better luck obtaining the archive from this
<a href="ftp://ftp.ims.uni-stuttgart.de/pub/WordNet">mirror</a> site in
Germany. As useful as this package is, it really should be mirrored
elsewhere as well.
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, Larry Ayers <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
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<center><h1>Words Within Words, New Phrases From Old</h1></center>
<center>
<h4>By <a href="mailto: layers@marktwain.net">Larry Ayers</a></h4>
</center>
<hr>
<center><h3>Introduction</h3></center>
<p>Sometimes after a long stint of putting words together it can be amusing
and relaxing to play with them for a while. Recently I discovered an anagram
search program for Linux which has some interesting capabilities not found in
other anagram programs I've seen. I'll also discuss an XEmacs mode called
Conx which does much the same sort of transformation on sentences or blocks of
text.
<center><h3>agm and xagm</h3></center>
<p>Fraser McCrossan is the author of <b>agm</b> and its Tcl/Tk interface
<b>xagm</b>. Like WordNet's <b>wn</b> (reviewed elsewhere in this issue)
<b>agm</b> is a command-line program, with <b>xagm</b> displaying its output
in an X window. I appreciate programs with this sort of dual nature because
they tend to be more portable. If Tcl/Tk isn't available the output could be
formatted and displayed using another GUI toolkit, or simply used as a console
program.
<p>I found this release (1.3.1) of <b>agm</b> in Sunsite's incoming directory,
but the archive was truncated. The included sample dictionary file was
incomplete, but this file isn't needed to use the program (a corrected version
was later uploaded which contains the complete dictionary file). Agm has the
useful ability to make use of any text file as a source of words, and if you
have <b>ispell</b> installed the dictionary file (in /usr/dict or
/usr/lib/ispell) can be a good collection of words for <b>agm</b>. Just
symlink it to <kbd>/usr/local/lib/words</kbd>. Several files can be
concatenated on the command line and used simultaneously; the (incomplete)
included dictionary file was created by combining several Project Gutenberg
files, including a 1913 edition of Webster's Dictionary, a Shakespeare play, a
couple of Mark Twain's works, the Jargon File, and three thesauri. This can
be done temporarily, i.e. for a single search, or a new word file can be
created; the default location is shown above, but this can be changed in the
Makefile. The ability to select input files would be especially useful for
non-English-speaking users.
<p>Here are screenshots of two <b>xagm</b> windows:<br>
<p>
<img alt="Main agm window" src="./gx/ayers/agm.gif">
<p>
<img alt="agm's output window" src="./gx/ayers/agm_out.gif">
<hr>
<p>A simple anagram search just takes a couple of seconds, but the time needed
grows exponentially as the input words or phrases grow longer.
Luckily there is an abort button in the Tcl version, and of course a
command-line <b>agm</b> search can be aborted with <kbd>control-c</kbd>.
Restricting the number of words in the output anagrams speeds the process up
considerably, as there are so many combinations with multiple
two-and-three-letter words. These anagrams tend to be less interesting, so a
search with the switch <b>-c2</b> is a good choice to start with.
<p>The supplied man-page will tell you everything you need to know and more
about <b>agm</b>, but the Tcl/Tk <b>xagm</b> interface is easy enough to use
that the man-page shouldn't even be needed unless you want to compile a custom
word-list. You might want to take a look at the <b>xagm</b> script and make
sure the first line points to your preferred Tk <i>wish</i> interpreter.
<p>The only source I know of for the program is the Sunsite
<a href="ftp://sunsite.unc.edu/pub/Linux/Incoming">incoming</a> directory; the
filename is <b>agm-1.3.1.tar.gz</b>. It will be moved eventually but shouldn't
be too hard to find.
<hr>
<center><h3>Conx-ing Text</h3></center>
<p>Buried in one of the directories of LISP files in any XEmacs installation
is an odd and interesting word amusement called Conx. Based on an earlier
implementation by Skef Wholey, Conx was rewritten in Emacs Lisp by Jamie
Zawinski in 1991, and was last modified in 1994.
<p>Conx is similar to the older Emacs mode Dissociated Press (accessed with
the command <kbd>alt-x dissociated-press</kbd>). Dissociated Press acts on
the current buffer, scrambling words and sentences to produce odd and
sometimes humorous juxtapositions. Conx-mode takes this concept further,
allowing a series of either selected regions or entire files to be loaded into
a sort of word database, then releasing scrambled output into an ever-growing
buffer; the process is terminated with <kbd>Control-g</kbd>.
<p>There are just a few commands for controlling this mode:<br>
<ul>
<li><kbd>alt-x conx-region</kbd>&nbsp;&nbsp;reads a selected area into the
database
<li><kbd>alt-x conx-buffer</kbd>&nbsp;&nbsp;reads in an entire buffer (these
commands are cumulative when repeated)
<li><kbd>alt-x conx-init</kbd>&nbsp;&nbsp;clears the database for a fresh
start
<li><kbd>alt-x conx</kbd>&nbsp;&nbsp;begins the conx process, outputting
scrambled text
into a new temporary buffer
<li><kbd>alt-x conx-save</kbd>&nbsp;&nbsp;saves the current database to a
file
<li><kbd>alt-x conx-load</kbd>&nbsp;&nbsp;reads a saved database, which is
faster than starting from scratch with the same text.
</ul>
<p>Conx-mode reminds me of the novelist William Burroughs' "scissors and
paste" method of combining text from various sources; he used this technique
in some of his published works. Semi-random text generation can be useful as
well as amusing. Sometimes it can help lift you out of verbal ruts and
provide a new view of familiar text and usage.
<p>In conclusion, here is an example of conx-mode applied to several
paragraphs from two sources: Sir Thomas Browne's seventeenth-century work
<cite>Religio Medici</cite> and Mark Twain's <cite>Huckleberry Finn</cite>.
<blockquote>Place where a hair ball would belch a community. Schism,
lonesomeness. Men away all the bullfrogs councils, and riddles of Tertullian.
Hurry, sparks was the sandy bottom where truth, to t'other side of the
cottonwoods and an old man hove a mile of one single heresy it to confirm and
an article to know by trade. Tar and cool and things we paddled over again
meant morning about knee deep, and confirmed opinion of the rule of the
church, or another, time. Pagans first cast at a spelling book. </blockquote>
<!--===================================================================-->
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<center><H5>Copyright &copy; 1998, Larry Ayers <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
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<center><h1>Comparing WordPerfect and LyX</h1></center>
<center>
<h4><a href="mailto: layers@marktwain.net">by Larry Ayers</a></h4>
</center>
<hr>
<center><h3>Introduction</h3></center>
<p>Some months ago I bought a copy of SDCorp's Linux port of Corel's
WordPerfect 7, and have spent a fair amount of time learning to use it; during
the same time-period I have also been using various pre-beta releases of LyX
0.11, and more recently the new 0.12 release. In this article I will attempt
to compare the two pieces of software, both of which are intended to produce
high-quality printed documents, but which have such radically different
methods of accomplishing this task. It's not quite an apples-and-oranges
comparison, but approaches that state.
<center><h3>WordPerfect 7</h3></center>
<p>The WordPerfect Corporation is now owned by the Canadian firm Corel, but
a group of former WordPerfect programmers and other employees in Utah
(WordPerfect's former home) have formed a company called SDCorp. This company
has ported WordPerfect 7 to Linux and other unix variants, and have made the
port available as a downloadable demo (see their
<a href="http://www.sdcorp.com/wplinux">web-site</a>); the program is also
available on CDROM. The demo can be registered by purchasing an e-mailable
key-file.
<p>A few years ago WordPerfect was one of the most popular word-processors
available, first under DOS then later in Windows versions. It still possesses
a significant user-base, but it has been losing ground recently to the
ubiquitous Microsoft Word word-processors. Any text-processing system which
uses a proprietary document format is reliant upon either other users making
use of the same format or the availability of high-quality document filters
for translating documents into other formats. Microsoft has made this
situation more difficult by continually "upgrading" their Word format in a
more-or-less backwards-incompatible fashion, forcing other software firms to
rewrite their document filters.
<p>WP occupies an increasingly rare niche in the text-processing world, as
it's a full-featured word-processor but isn't one component of a massive
"suite" of related programs, such as MS-Word, Applix, and StarOffice (at least
in the Linux version; the Windows version is sold as a suite component). This
has advantages and disadvantages. On the plus side you don't have to bother
with making room for components which you might not need, and the tendency
towards bloat is lessened. On the other hand, some users like the
interoperability of a suite's components, and disk space is cheap these days.
If you want a word-processor which is quick to start up, can print well on
most printers (including inexpensive dot-matrix machines), and does a good job
with included graphics files, WordPerfect is a good choice. Of course, the
price is a sticking point for Linux users accustomed to high quality free
software. What you get for the money is a wide variety of good printer
drivers, many input and output filters for different document formats, easy
graphics inclusion, and a time-tested interface and document-processing
engine. This word-processor is also less memory-hungry than some competing
products, requiring roughly the same resources as does GNU Emacs.
<p>One reason for WordPerfect's popularity is the "reveal codes" feature,
which shows an editable view of the current file with the internal formatting
codes visible. This gives the user more control of the underlying
text-processing, comparable to but not as extensive as the flexibility LaTeX
tagging allows.
<p>WordPerfect has its own documentation browser, complete with a handy
topic-search utility. Unfortunately the help is nowhere near as complete and
detailed as the exhaustive hardcopy manuals which used to be included with the
DOS versions.
<p>Making new fonts available to WordPerfect isn't immediately intuitive;
there is a separate program called <b>xwpfi</b> in the <i>/shbin10</i>
directory which facilitates this process. Rod Smith has written an
informative series of web-pages which contain useful techniques for dealing
with WordPerfect and fonts; they are available at
<a href="http://www.users.fast.net/~rodsmith/wpfonts.html">this site</a>.
<p>The April 1998 issue of the Linux Journal has a quite favorable review of
WordPerfect written by Michael Shappe. Since that review was written the
retail price has been reduced, and there is a fifty dollar discount if you
have an old version of WordPerfect or a registered copy of any of several
competing products. Incidentally, I've never noticed the slight keyboard lag
Michael Shappe mentions in his review; my hardware is roughly equivalent to
his, but for me WordPerfect keeps up with typing as well any text editor under
X. He did mention that his test machine is a laptop, so the difference in
video drivers and screen type may have something to do with his slow response.
<p>SDCorp has recently announced student pricing as well, which brings
the price ($59.00) closer to those of some competing products.
<center><h3>LyX</h3></center>
<p>From the free (or open-source) software world comes a different sort of
program with similar purposes. Lyx makes no attempt to display the exact
appearance of the document, just a version which is readable and looks good on
the screen. Rather then WYSIWYG (what you see is what you get) the developers
describe it as WYSIWYM (what you see is what you mean). The major difference
is the reliance upon a configured LaTeX installation. A typical TeTex
installation (the flavor of LaTeX supplied with both Redhat and Debian)
occupies about thirty megabytes of disk-space (add another five to six mb. for
LyX), while a WordPerfect installation needs over seventy. So a LyX
installation is really more compact, but some people are put off by the
reliance upon LaTeX, as it has a reputation of being abstruse, suited to
academics rather than to ordinary people desiring to compose and print out
nicely-formatted documents. One of the design goals of LyX is to shield the
user from needing to know too much about LaTeX and how it works, though
provision is made for users who would like to include LaTeX commands directly.
<p>LaTeX users often edit their marked-up text in a text editor (Emacs with
AucTeX is popular), leaving either xdvi or a Postscript previewer such as gv
or ghostscript running so that an updated view of the formatted document can
be viewed at will. This also works well with LyX, though it will seem to be a
cumbersome approach to users accustomed to the single document view of a
standard word-processor. Using LyX I more often don't view the formatted
document until a late draft, as the LyX-formatted view, though not identical
to the printed output, is close enough for writing purposes.
<p>If you have previously tried the last beta release, 0.10.7, 0.12 will come
as a pleasant surprise. After dozens of developer's releases in the past year
many bugs have been dealt with (and new features added), but even more
significant from a new user's perspective is the greatly improved
documentation. Several levels of help and introductory document files are
included, ranging from very basic (intended for people who have no experience
with LaTeX) to an exhaustively complete reference manual. Midway is the very
well-done User's Guide, which helped me get up to speed quickly. All of the
documentation is available from the menu-bar. Naturally (since LyX is still
in beta) some of the documentation is still incomplete, but in its current
state it is superior to much of the commercial software documentation I'm
familiar with.
<p>An interesting site-specific document is generated during installation and
is subsequently available from the help-menu. It's called
<b>LatexConfig.lyx</b>; it consists of an inventory of LaTeX packages found on
your system along with pointers for obtaining useful packages which may be
lacking.
<p>LaTeX (and thus LyX) is unparalleled in its handling of documents with
complex structure, dynamically keeping track of section numbers, footnotes,
and references even in book-length documents. WordPerfect's abilities in this
area are sufficient for most needs, but lack some of the dynamic updating LyX
is capable of.
<p>Though most non-academic users have little use for accurate rendering of
mathematical equations, LyX provides an easy-to-use and convenient interface
to LaTeX's mathematical modes. WordPerfect includes an Equation Editor which
can do most of what LyX can, but it's much less intuitive. I was able to
enter equations into a LyX document without reading the manual, whereas
WordPerfect's interface is cryptic, and it seems some study of the
documentation would be necessary to get very far with it.
<p>Many LaTeX users are still a little irked that while LyX can convert its
internal format to usable LaTeX, converting an existing LaTeX document still
isn't supported. Included with the LyX source (though not with binary
distributions) is a Perl script which can do limited conversion from LaTeX to
LyX. It doesn't work with all documents, but might be worth a try. This sort
of conversion is planned for a future version of LyX, along with compile-time
user-interface toolkit configurability. In other words, LyX could be compiled
with either the current XForms toolkit, GTK, Qt, or perhaps Motif. There have
been numerous complaints about the appearance and usability of the XForms
widget-set, with which LyX has been developed; personally I don't think it all
that objectionable, but being able to choose would still be welcome.
<p>Recently Matthias Ettrich, who started the LyX project a couple of years
ago, impulsively (along with one of the main KDE developers) ported LyX to
KDE, using the Qt tool-kit. Strictly speaking, there was nothing wrong with
doing this, as the source for LyX is free. But some of the other LyX
developers were unhappy about this, as it raised the possibility of a fork in
the development, and they were informed about this port after the fact. The
source for the Qt LyX port is available from <a href="ftp://ftp.kde.org">the
main KDE site</a>; it wouldn't compile for me, but you may have better
luck (for some reason, I've never been able to compile the KDE stuff). After
a few more beta source releases binaries of KLyX will be made available.
<center><h3>Conclusion</h3></center>
<p>These are both high-quality packages, but if either of my two teen-age kids
needs to type something for school I'll steer them towards WordPerfect. It
can be immediately be used by someone familiar with MS word-processors. LyX
has a little more of a learning curve, and its dependence on a working TeX
installation is often seen as a drawback by those unfamiliar with TeX. Any
up-to-date Linux distribution includes configured TeX packages which are easy
to install. LyX has the advantage of using a more portable document format;
files saved as LaTeX source can be edited in any text editor. It's also free,
and under active development.
<p>Since the initial release of WP 7 for Linux there have been no bug-fixes,
either as revised binaries or patches (that I know of). I imagine the
resources devoted to working on the SDCorp port hinge on the quantity of
copies sold. I wonder just how many licenses have been sold; in the free
software world, program enhancements and bug-fixes tend to be proportional to
the number of users and user/developers. Commercial software doubtless is
affected in similar ways.
<p>In my case, I've been able to get higher-quality printed output with WP
than with LyX, but the reverse is probably true for users with different
printers. Luckily the demo of WordPerfect will let you determine just how
well the appropriate printer driver works with a specific system. Rod Smith's
above-mentioned web-pages are an invaluable reference for setting up printers
and fonts for WP, while the LyX documentation contains a good overview of
configuring Ghostscript and dvips for use with LyX. It's not necessarily an
either-or situation; I like having both programs available, as they each have
their strengths.
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, Larry Ayers <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
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<H4>
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<center>
<H2>Pattern Matching with Regular Expressions in C++</H2>
<H4>By <a href="mailto:ogmueller@t-online.de">Oliver M&uuml;ller</a></H4>
</center>
<P> <HR> <P>
Regular expressions are the most flexible way to search for text
patterns. Since over twenty years they were used in several Unix tools
and utilities such as grep, sed, or awk. This article guides you to
implement this Unix base search technique in C++.
<P>
Everybody who has worked with a Unix system knows the useful regular
expressions. You find them in grep, awk, or emacs for example and they
are the most flexible way to specify search patterns. Everybody who has
ever used a tool like grep wants never miss its flexibility--or is there
anybody who wants?
<P>
The great usability of search tools such as grep is a result of regular
expressions. Remove these pattern matching technique from grep, substitute
it by another search algorithm, e.g., Boyer-Moore, and the resulting tool
is a toy--a fast toy, but a toy! (Do you know a DOS tool called <B>find</B>
which is a result like this...)
<P>
But joking apart. Pattern matching with regular expressions is the basis
of many search algorithms in many tools under Unix and so under Linux,
too. The power of this search technique is undisputed.
<P>
The target of this article shall be the implementation of regular
expressions in a reusable C++ class. This article shall be your guide
and introduction to the fascinating world of "pattern matching".
<P>
<H4>Principles</H4>
<P>
First of all a few principles about pattern matching with regular
expressions.
<P>
To specify a pattern you have to use a computer processable notation. This
notation, or language, is in our case the regular expression syntax.
<P>
The regular expression language consists of symbols and operators. The
symbols are simply the characters of the pattern. To describe the
relations between this symbols the following operators are used (listed
in descending priority):
<ul>
<li>Closure: A string of equal symbols
with variable length or an optional symbol. (This is the true heart of
pattern matching.)
<li>Concatenation: If there are two symbols in the
pattern successive, the corresponding characters in the text will have
to be successive, too.
<li>Alternation: One of the alternative symbols
must occur in the text in which the pattern is searched.
</ul>
In addition to these left associative operators brackets can be used to
modify the operation priorities.
<P>
The closure operators in most regular expression implementations
are:
<ul>
<li>the asterisk (*) which means a repetition of zero or more
occurrences of a symbol
<li>the plus (+) which means a repetition of one or
more occurrences of a symbol the question mark
<li>(?) which means a optional occurrence of a symbol
</ul>
Examples: A* matches empty string, "A", "AA",
"AAA", etc. A+ matches "A",
"AA", "AAA", etc. A? matches empty string or
"A".
<P>
To specify a concatenation no special operator character must be used. A
string consisting of each other following symbols are a concatenation. ABC
matches "ABC" for example.
<P>
An alternation is described with a "|" between the alternative
regular expressions. A|B matches either "A" or "B".
<P>
In extended regular expression implementations a few other operators used
to describe complex patterns more efficient. But this article shall be
only a little introduction into the syntactical possibilities and not
a detailed reference.
<P>
<H4>The Automaton</H4>
<P>
To search for a pattern which is specified by a regular expression you
cannot compare each character of the pattern and the text. Caused by the
closure and the alternation there are so many possible ways in complex
patterns that they cannot all proved by a "conventional" algorithm.
A more efficient technique must be applied. The best way is to build
and simulate an automaton for the pattern. To describe a search pattern
specified by a regular expression you can use non-deterministic or
deterministic finite state automata.
<P>
An automaton can assume several states. It can pass from one state into
an other depending on a specific input event which is in our case the
next input symbol respectively character. And here is the difference
between deterministic and non-deterministic finite state automata. A
deterministic automaton has only <B>one</B> next state for a specific
input symbol. A non-deterministic automaton can have <B>several</B>
next states for the same input symbol.
<P>
Both kinds of automata can be used for every imaginable regular
expression. The two types of automata have there own advantages
and disadvantages. For everybody who wants to know more about these
automata types in context with regular expressions the book /1/ can
be recommended. In our implementation we will use non-deterministic
automata. It's the most used strategy to implement a pattern matching
algorithm and it's a bit easier to construct a non-deterministic than
a deterministic automaton basing on a regular expression.
<P>
Figure 1 shows a state transition diagram of a non-deterministic
finite state automaton for the pattern a*(cb|c*)d. It contains all
types of operations--an alternation, two closures and tree concatenated
symbols. Note that the bracket which contains the alternative symbols
is one symbol for the concatenation. The start state is the rectangle
at the left side. The finite state is shown at the right side--rectangle
with diagonal line.
<P>
<center>
<img src="./gx/mueller/2462f1.gif">
<P>
<H4>Figure 1. Non-deterministic finite state automaton for pattern a*(cd|c*)d.</H4>
</center>
<P>
This little pattern and its automaton demonstrates the problems of pattern
matching very well. At state No. 7 it is not sure which state will be
the next for a input character "c". The states 4 and 9 are possible
ways. The automaton has to find out--to guess--the right way.
<P>
If the text string "aaccd" shall be matched for example the automaton
will start at state No. 0--the start state. The next state, No. 2, is
a zero state. This means that there is no character which must match to
enter this state.
<P>
The first input symbol is a "a". The automaton goes to state
No. 1 which is the only way. After matching the "a" the next input
character will be read and the next state is No. 2 again. For the next input
character which is also a "a". the last two steps are repeated.
After this the only possible way is to go to state No. 3 and 7.
<P>
Here we are in the state which may cause problems. The next input is
a "c". Here we see the true power of the automaton. It can guess the
right way which will be state No. 9 and not No. 4. This is the soul of
a non-deterministic strategy: the possible solutions are found out. They
are not described by an algorithm which works "step by step".
<P>
In the real world of programming we have to prove all possible ways,
of course. But more about the practical side a bit later.
<P>
After the decision pro No. 9 the automaton goes over 9, 8 (1st c matches),
9, 8 (2nd c matches), 10 and 11 (d matches) to state No. 12. The end
state was reached and the result is that the text "aaccd" matches to
pattern "a*(cb|c*)d".
<P>
<H4>Design</H4>
<P>
A regular expression implementation can always be split into a compiler,
which generates a automaton from the given pattern, and an interpreter
or simulator, which simulates the automaton and searches for the pattern.
<P>
The heart of the compiler is the parser which bases on the following
context free grammar:
<pre>list ::= element | element "|" list
element ::= ( "(" list ")" | v ) ["*"] [element]
</PRE>
This EBNF diagram (=Extended Backus-Naur Form) describes the (reduced)
regular expression grammar. It is not possible to explain context free
grammars or the EBNF in this article. If you are not familiar with these
topics I can recommend /1/ and /3/ for example.
<P>
In our sample implementation we will only implement the basic operators
| and *. The other closure operators + and ? we will not implement. But
with the help of Figure 2 it will no problem for you to implement it, too.
<P>
The complete regular expression functionality will be encapsulated
in the object class RegExpr. It contains the compiler and the
interpreter/simulator. The user is only confronted with the two
constructors, one overloaded operator and four methods for compiling,
searching, and error handling.
<P>
The pattern can be specified by calling the constructor RegExpr(const
char *pattern), by using the assign operator = or the compile(const char
*pattern) method. If re is an object of RegExpr the following lines
will set the pattern "a*(cb|c*)d":
<pre>RegExpr re("a*(cb|c*)d");
<B>or</B> RegExpr re; re = "a*(cb|c*)d";
<B>or</B> RegExpr re; re.compile("a*(cb|c*)d");
</PRE>
To search in a text buffer or string you can use the methods search()
and searchLen(). The difference between these methods is that searchLen()
expects a reference to a unsigned integer variable as an additional
parameter. In this variable the length of the matching substring is
return. Note that the closures, but also the alternation, cause that
the length of the found substring can vary, e.g., a* matches
"", "a",
"aa", etc.
<P>
In tools, such as grep, you won't need this additional information. Here
you can use search instead of searchLen(). This method is a simple inline
which calls searchLen() with a "dummy" variable.
<P>
<center>
<img src="./gx/mueller/2462f2.gif">
<P>
<H4>Figure 2. These are the automata for the closure implementation.</H4>
</center>
<P>
The error handling is complete exception based. If the compiler indicates
a syntax error in the currently processed regular expression it will
throw an exception of type xsyntax. You can catch this exception in your
program and call the method getErrorPos() which returns the character
position at which the error occurred. This may look like this:
<pre>try {
re.compile("a*(cb|c*)d");
} catch(xsyntax &X) {
cout << "error near character position "
<<
X.getErrorPos() << endl;
}
</PRE>
Another error which can occur is "out of memory". This
error--caused by
the new operator--isn't uniform processed by current C++ compilers. gcc
for example handle such an error with a program termination. Some
compiles throw exceptions. The rest does absolutely nothing and waits
for other errors which will definitely occur. You solve this problem
in every ANSI C++ compiler by using the function set_new_errorhandler()
(declared in new.h) to set a routine to handle this error. In most cases
I write a little routine to throw an exception which indicates this error
type and set this routine as error handler for the new operator. This is
by the way an easy solution to program a portable error handling which
can be used by all ANSI C++ compilers and under every operating system.
<P>
A RegExpr object contains a method called clear_after_error() to clear
itself when a error occurred respectively a exception was thrown. A
call of this method is necessary because an error leaves the compiler or
simulator in a indefinable state which can cause fatal errors at other
method calls.
<P>
<H4>The Compiler</H4>
<P>
The grammar which was previously shown in an EBNF diagram is implemented
in the methods list, element and v. list and element represent the
productions of the EBNF. v is a method which implements the special
symbol v. This symbols means in the grammar a character which is not a
metacharacter (|, *, etc.). It can also be a backslash sequence like \c
where c is any character. By using the backslash the special significance
of a metacharacter can be removed.
<P>
This three methods operate on a array called automaton. The array
consists of struct variables which contain information of the states
of the automaton. Every state entry contains the indices of the next
state(s) and the character which have to match. If the state is a zero
state this information will be a zero byte ("\0").
<P>
<center>
<img src="./gx/mueller/2462f3.gif">
<P>
<H4>Figure 3. The parse tree of "a*|b".</H4>
</center>
<P>
Our implementation is a top down parser. It uses directly the recursive
strategy of the context free grammar--every production is coded as
a function. The parser splits the who pattern respectively regular
expression into lower parts until it reaches a terminate symbol. Figure
3 shows the parse tree for "a*|b". First list is entered which
branches into non-terminate element, terminal "|" and non-
terminate list. element detects v and "*" and goes down to
"a". The other list
part goes directly down to "b" by passing element and v. The parse
tree of our sample regular expression can be seen in Figure 4.
<P>
<center>
<img src="./gx/mueller/2462f4.gif">
<P>
<H4>Figure 4. The parse tree of "a*(cb|c*)d"</H4>
</center>
<P>
Every non-terminate symbol represents a function call in our parser. The
top down strategy is the easiest way to implement a parser from a context
free grammar respectively EBNF diagram. You see the most important thing
here is an error free grammar specification!
<P>
Inside this methods the states of the automaton are generated. For every
character of the regular expression a state will be created. The only
exception is the operator | which will be compiled to two states.
<P>
The methods return to its caller always the entry point (index of state)
to the generated part automaton. The end of the part automaton is always
the last current state which index is stored in the attribute state of
RegExpr. You see the several part automata in Figure 5.
<center>
<img src="./gx/mueller/2462f5.gif">
<P>
<H4>Figure 5. A Several Part Automata</H4>
</center>
<P>
The red numbers indicate the new generated states for the operation. The
succession of the numbers is defined by the parser which reads a string
from left to right. The returned entry point or state is marked, too. You
realize that it is very important to tell the calling function where
the entry point is because it isn't always the one with the lowest index!
<P>
The states--and so the whole automaton--are generated in this way step
by step by a top down parser. It isn't very helpful for you to write
more about this automaton creation. It's better you type in the sources,
compile it and watch the algorithm in action by using a debugger.
<P>
A little annotation to the automaton. It is implemented by the static
array automaton in RegExpr. This is definitely a poor rudimentary
implementation. In a practical and useful program you have to use a
better strategy, e.g. an aggregate object class in RegExpr which works
with a dynamic array.
<P>
Note that this implementation of the automaton can cause fatal errors
if the pattern is to large! It has no checking function which breaks
pattern compilation if there are no more states.
<P>
But it is not difficult to implement the automaton as class which
administrates it in a dynamic array or a linked list.
<P>
<H4>The Automaton Simulation</H4>
<P>
After the compilation of the pattern we can execute the generated code
respectively simulate the automaton. The complete intelligence of the
search algorithm is implemented in the method simulate().
<P>
It was previously hinted that the automaton guesses the right answer but
this a theoretical view. A computer simulation of a non-deterministic
finite state automaton must prove every possible matching way through
this automaton. Sedgewick (/3/) has implemented a interesting algorithm
to do this. Our algorithm shall base on this technique.
<P>
Sedgewick's system has some disadvantages for practical application. The
First disadvantage is that its grammar needs a character after a closure
otherwise it can't find it. But this is a problem which can be solved by
a patch very soon--and our implementation has already solved this. The
second problem is a bit more complex. Sedgewick's implementation quits
after the first match. This means that it doesn't find the longest
matching string. For example: If you search for "a*a" in
"xxaaaaaxx"
it will find only "a" instead of "aaaaa". Our
implementation will solve this problem.
<P>
The idea that a program can guess the right way might sound
ridiculous. But the heart of such a software is to prove all possible way
and accept the last matching as the right. Here is a parallel proceeding
the decisive key.
<P>
Every branch of the automaton will be tested and if not fitting
removed. It's a bit a "trial and error" method. Every possible way will
be tested parallel with the others and removed when not matching the
current processed character of the search through text.
<P>
The basic element of this algorithm is a deque. A deque is a double ended
queue. It's a hybrid between stack and buffer. You can push and pop data
(stack) but also put (buffer). In other words: You can add data to the
head and to the tail of this data structure.
<P>
This behavior is important for our algorithm. The deque is split into
two parts:
<ol>
<li>top part for the current processed character of the
search through text
<li>bottom part for the next character
</ol>
The next state values of zero states are stored on the top part because
they implement the structure which is necessary to detect a match
of the current character. The next state values of non-zero states
(<tt>the_char != '\0'</tt>) are put to the bottom part because they point to the
next character. Between these part is a special value stored--next_char
(-1). It indicates that the next character of the text shall be processed.
<P>
The main loop in simulate gets a state from this deque and tests the
conditions. If the character in the_char of this state matches the
current processed character in the searched through text the indexes of
the next states (next1 and next2) will be put at the end of the deque. If
the read state is a zero state the next state values will be put on the
start of the queue. If the state is next_char (-1) the next character
in the searched through text will be processed. In this case next_char
is put at the end of the deque.
<P>
The loop will be terminated if the end of the text is reached or the deque
is empty. The last case arises when no more matching parts are found.
<P>
As so far it sound like the version of Sedgewick but the difference is
that when state becomes zero the loop won't terminate. It is accepted
as a matching part and this information is stored but the loop will go
ahead! It will search for possible other matches.
<P>
After the termination of the loop I returns the last matching result
or--if the pattern wasn't found--the start position of the search
minus one.
<P>
<H4>A Little Sample Application</H4>
<P>
To download the listings and makefile, click
<A HREF="./mueller.tar.gz">here</A>.
<P>
<B>eg.cc</B> is a little egrep implementation. It shall demonstrate the usage
and the power of RegExpr. eg reads from standard input or from a optional
specified file and print every line which contains the pattern:
<pre>Usage: eg pattern [file]
</PRE>
RegExpr is in this (minimal) implementation not perfect of course but it
will be a good basis for experiments. A few things which can be changed
or implemented are:
<ul>
<li>The closures ? and +
<li>Implementation of automaton as object with dynamic array or
linked list as state administration
<li>Character classes [...]
<li>Metacharacter . for any character
<li>Other operators known from sed or ed {...}
<li>Start and end line metacharacters--^ and $
</ul>
Last but not least I hope that you will have a bit fun with this
implementation. If you have some suggestions, questions, or ideas please
let me know.
<H4>Resources</H4>
<ul>
<li>Aho, Alfred V. / Sethi, Ravi / Ullman, Jeffrey
D.: COMPILERS Principles, Techniques and Tools. Reading (Mass.): Addison
Wesley 1986
<li>M&uuml;ller, Oliver: Mustererkennung mit Delphi-Suchen
und Ersetzen von regulaeren Ausdruecken. mc extra (DOS International)
7/96
<li>Sedgewick, Robert: Algorithms. Reading (Mass.): Addison
Wesley 2nd Ed. 1992
</ul>
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, Oliver M&uuml;ller <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
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<center>
<H2>Book Review: Web Security Sourcebook</H2>
<H4>By <a href="mailto:kirk@muppetlabs.com">Kirk Petersen</a></H4>
</center>
<P> <HR> <P>
<img align="right" src="./gx/petersen/cover.gif">
<ul>
<li>Authors: Aviel D. Rubin, Daniel Geer and Marcus J. Ranum
<li>Publisher: John Wiley and Sons
<li>E-mail: <a href="mailto:info@qm.jwiley.com">info@qm.jwiley.com</a>
<li>URL: <a href="http://www.wiley.com/">http://www.wiley.com/</a>
<li>Price: $23.99 US
<li>ISBN: 047118148X
</ul><P>
<I>Web Security Sourcebook</I> claims to be "a serious security
source book for Web Professionals and users."
Each chapter
covers one aspect of security, ranging from basic browser security to
firewall design.
<P>
The material covered in <I>Web Security Sourcebook</I> is fairly
simple--I would expect that
any Linux user could easily understand everything
presented in the book.
The target audience for <I>Web Security Sourcebook</I>
is anyone with some computer experience but with little knowledge
of computer security. It is mostly a summary of beginning, and some
intermediate, topics.
<P>
<H4>Chapter Summary</H4>
<P>
The first chapter, "Caught in Our Own Web", is the introduction to
the book. The authors present a quick history of the Web split
into four stages: the beginning, HTTP, server-side scripts and
client-side scripts. Security features (authentication,
confidentiality, etc.) are quickly outlined.
<P>
Chapter two, "Basic Browser Security", outlines
the features of Netscape Navigator and Microsoft Internet Explorer. The
authors cover all of the preferences that deal with security and
comment on how they should be configured.
A section on Internet Explorer's Content
Advisor (basically a Web "ratings" system) is included.
<P>
The next chapter is mostly about user privacy. There is a
section that describes certificates, mostly describing their flaws,
a very brief section on passwords and a good description of cookies.
Then the authors turn to privacy and anonymity. Simple proxies, Chaum
mixes and anonymous remailers are also described.
<P>
Chapters four and five address the security concerns of client-
and server-side scripts. Security issues of Java, Javascript and
ActiveX are outlined. The section on server-side security covers system
security as well as web-server security. It is mostly aimed at
Unix users.
<P>
The next chapter, "Advanced Server-Side Security"
consists mainly of CGI scripts and server-side includes. Information about
code signing and auditing tools is also provided.
<P>
"Creating Secure CGI Scripts" is the name of chapter seven.
It informs the reader of a few common security holes in
CGI scripts. It also outlines Perl, Tcl and Python as three capable
CGI scripting languages.
<P>
Chapter eight is an introduction to firewalls. The authors
describe what firewalls can do and how they interact with various
protocols. The placement of the firewall is explained in the second
part of the chapter.
<P>
Chapters nine and ten outline transactions on the Web. IPSEC is
discussed in detail. Secure HTTP, SSL and PCT are explained. The
authors then explain several "digital money" standards. A good
comparison is done between six of the competing standards.
<P>
The final chapter outlines the future of security on the Web. It
explains the problem of building in security "after-the-fact". The authors
point out some issues that often affect security, although they aren't
always thought of in that sense (such as "deliberate
incompatibility").
The chapter ends with a section titled "What we need in the
future".
<P>
The book includes two appendices. The first one is a brief
description of encryption, hash functions, digital signatures and so on.
The second one is a list of all the books and URLs that the authors
mentioned in the book.
<P>
<H4>Conclusion</H4>
<P>
<I>Web Security Sourcebook</I>
is fairly light reading and can be finished quickly. The writing is
adequate, although there are places where I found the descriptions lacking
or imprecise.
<P>
One thing that I often find annoying about security-related writings
is the use of scare tactics.
<I>Web Security Sourcebook</I> does have its share of scare tactics, but
for the most part uses realistic stories that honestly try to
inform the reader.
<P>
The information that <I>Web Security Sourcebook</I> presents is useful although
a bit shallow. The book tries to cover a lot of ground and is only
350 pages. If the book had been devoted solely to practical security fixes,
it might have impressed me. However, it included only a few specifics and
then went on to describe firewalls and transaction standards (which would
also have been interesting in more detail).
<P>
If you want an introduction to Web security and you have very little
experience with any sort of computer security, you might be interested in
<I>Web Security Sourcebook</I>. If you know much about encryption, or have
studied firewalls, or know about quite a few Web client and/or server
security holes, you will probably be disappointed by this book.
<P>
If you want to learn everything that was covered
in this book and you have the money, I would suggest getting a specific
book on each of the three or four concepts that <I>Web Security
Sourcebook</I> covers.
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, Kirk Petersen<BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
<!--===================================================================-->
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<H4>
"Linux Gazette...<I>making Linux just a little more fun!</I>"
</H4>
<P> <HR> <P>
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<CENTER>
<IMG ALT="Linux Weekend Mechanic" SRC="../gx/fisk/wkndMech.gif" ALIGN=BOTTOM
WIDTH=397 HEIGHT=150>
<H1>Welcome to The Linux Weekend Mechanic!</H1>
<H2>Published in the April, 1998 Edition of the Linux Gazette</H2>
<FONT SIZE="2"><B>
Copyright &#169; 1997 John M. Fisk &lt;fiskjm@ctrvax.vanderbilt.edu&gt;<BR>
The Linux Gazette (tm) is Copyright &#169; 1997,1998 <A HREF="http://www.ssc.com/">
Specialized Systems Consultants Inc.</A>
</B></FONT>
</CENTER>
<P><HR><P>
<!-- CLOSE UP SHOP ================================================ -->
<A NAME="closeup">
<CENTER>
<IMG SRC="../gx/fisk/closing.gif" WIDTH=555 HEIGHT=95 ALIGN=BOTTOM
ALT="Closing Up Shop"></CENTER>
</A>
<CENTER>
<H2>I'm leaving y'all for another woman...!</H2>
<P>
<IMG SRC="./gx/fisk/faith-n-john.gif" WIDTH=200 HEIGHT=231 ALT="Faith and John">
<P>
My wonderful wife... :-)
</CENTER>
<P>
Yup, I'm afraid that it's time to permanently close up shop here at the 'ol
Weekend Mechanic. Time constrains and just the day to day necessities are
starting to catch up and I just simply need to spend more time taking care of
family matters. I sat down and figured out the time the other day: I've been
in some form of training -- undergraduate, graduate, or residency -- for the
past <I>13 1/2 years!</I> I'm about to take a sabbatical :-)
<P>
But before I go, I need to take a minute and say thanks to an awful lot of
folks: to Tim, at Tennessee Commerce Net, who graciously offered to host the
Linux Gazette way back in the summer of 1995; to Matt Welsh for his kind offer
to bring the LG under the wing of the LDP; to Marc Ewing, Donnie Barnes, &amp;
Erik Troan, the &quot;Boys at RedHat&quot; who sent their encouragement (as
well as CD's, a t-shirt, books, and the familiar Red Hat... thanks!) way back
when; to Phil Hughes for his interest in and willingness to take over the LG
when it simply became too much; to Marjorie Richardson, for actually <I>taking
over</I> the day to day care and feeding of this thing (as well as shouldering
the hassles and burdens that come with this job -- such as truant columnists
such as your's truly...); to the myriad of authors and contributors who have
much more faithfully than me contributed to the success of the LG by giving of
their time and talents...
<P>
And mostly, to my lovely wife, without whose unflagging love, support, and
encouragement (and willingness to be an all-too-frequent &quot;computer
widow&quot;) none of this could have happened. To all of you I want to humbly
say,
<P>
Thanks folks, it's been great.
<P>
So what are we now up to?
<P>
Well, as most of you know, I finished up at <A HREF="http://www.mtsu.edu/">
Middle Tennessee State University</A> this past December and immediately
started working for Dr. Ed Shultz in the Information Management Department
here at Vanderbilt. We've licensed a clinical database system from a Dr.
Prakash Nadkarni at the Yale University Medical Center. Dr. Nadkarni's
Advanced Clinical Trials Database System (ACT/DB) is a rather sophisticated
clinical trials data management system currently hosted in the Oncology arena.
My job has simply been to get the system working and integrated into the
larger clinical information system here at Vandy, which has so far proven to
be an interesting and often challenging endeavor. For those who might be
interested in such things, Dr. Nadkarni has an article in this month's (March,
1998) Journal of the American Medical Informatics (JAMIA) describing the
ACT/DB system. We've also submitted an abstract for a theater presentation of
the system at the upcoming AMIA meeting (again, for you medical informatics
type folks out there... :-)
<P>
I'm also working now on trying to set up a formal Medical Informatics
Fellowship through the National Library of Medicine here at Vanderbilt. A
good deal of my time is now spent trying to get ready for this, especially as
the August 1 submission deadline approaches.
<P>
Anyway, if you've made it this far, thanks for hanging in there. I really do
owe one last HUGE bit of thanks...
<BLOCKQUOTE>
<P>
Dear Linus,
<P>
Thanks so much for one <I>drop-dead kool</I> kinda OS!
<P>
Your fan,<BR>
John
</BLOCKQUOTE>
<P>
I'll see y'all around. Take care,
<P>
John
<!-- END CLOSE UP SHOP ================================================ -->
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<CENTER>
<IMG SRC="../gx/fisk/mailme2.gif" ALT="Mail Me a Note" ALIGN=BOTTOM WIDTH=398
HEIGHT=54><BR>
</CENTER>
<P>
Got any comments, suggestions, criticisms or ideas?<BR>
Feel free to drop me a note at:<BR>
<ADDRESS> John M. Fisk
<A HREF="mailto: fiskjm@ctrvax.vanderbilt.edu">
&lt;fiskjm@ctrvax.vanderbilt.edu&gt;</A>
</ADDRESS>
<P>
<FONT SIZE=-1>
Document Information:<BR><B>
$Id: issue27.html,v 1.3 2003/02/03 21:50:18 lg Exp $
</B>
</FONT>
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, John Fisk <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
<!--===================================================================-->
<P> <hr> <P>
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ALT="[ TABLE OF CONTENTS ]"></A>
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<H4>
"Linux Gazette...<I>making Linux just a little more fun!</I>"
</H4>
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<!--===================================================================-->
<DIV align="center">
<H1>
X Window System Terminals
</H1>
<img width=320 height=240 border=1 alt="486 X Terminal" src="./gx/kaszeta/xterminal.gif">
<h2> A New Use for Old and Outdated PCs</h2>
<h3> by <a href="mailto:bofh@me.umn.edu">Rich Kaszeta</A> </H3>
</div>
<hr>
<h2>Summary:</h2>
<p>This page describes how to convert low-end 386/486 PC's into standalone
X Window Systems terminals which can serve as graphical terminals to
your existing Linux/Unix workstations.
<h2>Background:</h2>
<p>Here at the <a href="http://www.me.umn.edu/">Mechanical Engineering
Dept.</a> at the University of Minnesota, we inherited a number of old
IBM PS/Valuepoint 486 machines (16 Meg memory, 200 Meg HD) with
keyboards and monitors, and were trying to find a way to get some good
use out of them.
<p>Originally, we discussed placing Linux on them (our department
already has dozens of Pentium-class Linux machines which are quite
popular), but decided that with their low disk space and memory they
wouldn't run fast enough to suit our current users' needs, and that it
wasn't economical to upgrade them.
<p>Our solution was to install a minimal Debian Linux system on them
(base install plus basic networking, X, and a few utilities), and
configure them to act as X terminals, allowing us to provide
extremely cheap fully-graphical terminals, which are used in graduate
student offices and as X interfaces to our headless Unix servers.
<h2>XDM: The basic concept:</h2>
<p><tt>xdm</tt> is a "display manager", providing X login windows to
users. The traditional use of xdm is to provide a graphical login on
the local display on an X11 workstation, so that the user does not
need to start up X "by hand".
<p>However, <tt>xdm</tt> can also provide graphical X11 logins to
remote machines, such as NCD Xterminals. The only requirement is that
the remote machine speak X.
<p>What we are describing here is configuring a cheap PC to act just
like one of these Xterminals.
<h2>Setting up the X Terminals</h2>
<p>Setting up the 486 PCs as graphical X terminals fairly
straightforward, consisting of just a few steps:
<OL>
<LI>Installing a minimal Debian Linux system on each PC
<LI>Configuring each PC to start up X and query an XDM server to get a
list of hosts to connect to.
<LI>Configuring one or more XDM servers to provide "chooser" services
to the X terminals.
<LI>Configuring XDM and the chooser to be more aesthetically pleasing
and useful.
</OL>
<P>I'll discuss each of these steps in turn.
<h3>Installing a minimal Linux system:</h3>
<p>Since our existing Linux systems run <a
href="http://www.debian.org">Debian Linux</a> we chose to use it for
these PCs as well.
<p>On each system, we installed just the basic Debian system from
floppy, which provides a very bare-bones Linux system with networking
support. No user accounts were created, since none are needed (since
no users actually log into the machine itself).
<p>Next, Debian packages of XFree86 3.3 were loaded on each system.
We loaded the base X11 libraries, the X extensions, the S3 X server
(since the PS/Valuepoints have 2-meg S3-based video card), and all the
X11R6 fonts.
<p>Finally, we installed a few additional packages for convenience,
including basic networking utilities (<t>netbase</t>), <tt>ssh</tt>
(to allow use to remotely log in through a secure channel), and
<tt>nvi</tt> since the systems staff here doesn't like the default
Debian text editor.
<h3>Configuring each PC to start up X:</h3>
<p>The first step was configuring X to run locally on each PC. An
<a href="XF86Config"><tt>XF86Config</tt></a> file was created for the machines using the standard
'<tt>xf86config</tt>' utility, with a couple of considerations:
<UL>
<LI>The "Emulate3Buttons" option was enabled, since the mice that came
with the machines are only 2-button mice.
<LI>While the 2-meg S3 card in the Valuepoints is capable of up to
1152x900x16bit resolution, we chose to run 1024x768x8bit, since it
runs at a more comfortable refresh rate, better viewability on the
15-inch IBM monitors, and provides better compatibility with local
applications than 16-bit color.
<LI>For added security, "DontZap" is specified so that users cannot
inadvertently kill the X server.
<LI>We added additional SGI-defined colors to
<tt>/usr/lib/X11/rgb.txt</tt> so that the X-stations could talk to our
SGIs without errors.
<LI>You may wish to set up a font server somewhere.
</UL>
<P>Once we were satisfied with the configuration of the X server, we
then tested if it could connect to a workstation running xdm ("rayleigh" in
this example):
<pre>
X -quiet -query weber
</pre>
which gives us the standard xdm login window for "weber":<p>
<div align="center">
<img border=1 width=629 height=402 alt="standard xdm login window"
src="./gx/kaszeta/xdm1.gif">
</div>
<P>So, we now know everything is basically working. If we just want the PC to
talk to a single workstation, then we are basically done. The only
remaining step is to make sure that X is started upon bootup. We can
do this with a script in <a href="xterm1"><tt>/etc/init.d/xterm</tt></a>.
<P>On a Debian system, we install it with '<tt>update-rc.d xterm defaults
99</tt>'. (The procedure for Redhat, Slackware, etc., is similar).
We then reboot the machine to make sure it starts X upon boot.
<h3>Configuring an XDM server to provide a "chooser":</h3>
<P>We've already set up a basic X Terminal. However, it can only talk to
a single machine. If we would like it to be able to connect to a
number of other machines, we'll have to have at least one machine in
our network configured to provide a host "chooser" to our X terminals.
In this discussion, the machine providing "chooser" xdm services is
called "weber" (note that in this example "weber" is a Linux box, but
it could be any xdm-enabled workstation).
<P>The first step is to configure weber to provide the chooser to
hosts that connect through an "indirect" XDM connection. This is
controlled by the <tt>Xaccess</tt> file (located in
<tt>/etc/X11/xdm</tt> on Debian machines, it may be located under
<tt>/usr/lib/X11</tt> or another location on other machines).
Typically, the default <tt>Xaccess</tt> file on most systems is fairly
well commented and includes a number of simple examples, so it's
pretty easy to figure out.
<P>Basically, you have to add a line to the file of the form
<pre>
hostname CHOOSER host-a host-b
</pre>
where <tt>hostname</tt> is the name of the host to provide the chooser
to (it can be a wildcard such as "<tt>*</tt>" or
"<tt>*.domain.name</tt>", the <tt>CHOOSER</tt> tells <tt>xdm</tt> to
provide a chooser to these hosts, and the remainder of the line is a
list of machine names to list in the chooser. If you use the special
hostname <tt>BROADCAST</tt>, it will list all xdm-enabled machines on
the local network.
<p>So, if we want all machines to be given a chooser that allows them
to select any machine on the local network, we'd make sure
<tt>Xaccess</tt> has the line
<pre>
* CHOOSER BROADCAST
</pre>
<p>However, in our system we have a number of machines in different
subnets, so we can't rely on a broadcast to find them all. So we use
<pre>
* CHOOSER machine list ...
</pre>
instead.
<p>Additionally, we can specify different lists for different
machines. As mentioned previously we wanted to use one of the PCs as
a graphical terminal for our headless SGI workstation (which runs
xdm). So we have this machine, "console", be given a list of only the
server machines:
<pre>
console.me.umn.edu CHOOSER server1 server2 ...
</pre>
<p>The next step is to modify the X terminal to connect to the XDM
server using an 'indirect' query. We first test it by logging into
the X terminal PC, and starting X with
<pre>
X -indirect weber
</pre>
and we should then see the chooser come up:<p>
<div align="center">
<img border=1 width=799 height=589 alt="standard chooser"
src="./gx/kaszeta/chooser.gif">
</div>
Functional, but a little ugly.
<p>So now that we know it works, we change our
<a href="xterm"><tt>/etc/init.d/xterm</tt></a> script, replacing the
"-query rayleigh" with "-indirect weber".
<h3>Configuring the chooser through X resources and scripts:</h3>
<p>Well, now that we've got everything basically working, all that we
have left is to clean up the configuration of the chooser so it is a
little more useable and visually pleasing.
<p>The chooser can be configured using X resources. By changing these
resources we can do things such as change the chooser fonts, the
layout of the list, and the colors. These resources are set in
<tt>/etc/X11/xdm/Xresources</tt> (or a similar location on non-Debian
machines).
<p>On our systems, we wanted to do the following:
<ul>
<li> Change the header to say "Available MEnet Systems"
<li> Change the fonts to be more legible
<li> Make the list two column, with a gap between the columns, and
sorted vertically.
<li> Move the scrollbar to the right.
<li> Enlarge the window slightly.
</ul>
To accomplish this, we edited <tt>/etc/X11/xdm/Xresources</tt> to
insert the following:
<pre>
Chooser*geometry: 810x500+300+225
Chooser*allowShellResize: false
Chooser*ShapeStyle: Oval
Chooser*viewport.forceBars: true
Chooser*label.font: *-new century schoolbook-bold-i-normal-*-240-*
Chooser*label.label: Available MEnet Hosts
!Chooser*list.font: -*-*-medium-r-normal-*-*-230-*-*-c-*-iso8859-1
!Chooser*Command.font: *-new century schoolbook-bold-r-normal-*-180-*
#ifdef COLOR
Chooser*label.foreground: white
Chooser*label.background: midnightblue
Chooser*Command.background: gray80
Chooser*list.columnSpacing: 25
Chooser*list.defaultColumns: 2
Chooser*list.forceColumns: true
Chooser*list.verticalList: true
Chooser*internalBorderColor: black
Chooser*Command.font: -adobe-helvetica-bold-r-*-*-12-*
Chooser*viewport.useRight: true
#endif
</pre>
<p>Finally, we wanted to get rid of the default X11 "thatch" pattern
on the root window, since it gives a horrid moire effect on small
monitors. To do this, we tell xdm to use a shell script, called
"chooser.script" instead of the normal "chooser". This script simply
sets the background to "skyblue4" and runs the normal chooser. We set
this in <tt>/etc/X11/xdm/xdm-config</tt>, adding the line
<pre>
DisplayManager*chooser: /usr/lib/X11/xdm/chooser.script
</pre>
where "chooser.script" is
<pre>
#!/bin/sh
xsetroot -solid skyblue4
/usr/lib/X11/xdm/chooser $*
</pre>
The final result looks like:<p>
<div align="center">
<img width=876 height=563 border=1 alt="customized chooser"
src="./gx/kaszeta/chooser2.gif">
</div>
Much nicer, no?
<p>A <strong>lot</strong> more customization is possible, through both
X resources and the XDM configuration scripts. Consult the
<tt>xdm</tt> man page for more details.
<h2>Conclusion:</h2>
<p>With relatively little work, and very little subsequent
administration (the X terminals seldom crash, and don't need software
updates), we converted a bunch of "junker" PCs into rather useful X
terminals (I've even done a 386 this way and it runs fine).
<p>As a final note, it's important to point out the while the
particular systems I've described here are PCs running Debian Linux,
the same technique applies equally well to resuscitation of any older
X11-capable machines, such as older Suns (Sparc ELCs), HPs, and
SGIs...
<P>
<a href="http://www.menet.umn.edu/~kaszeta">Rich Kaszeta</a>
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1998, Rich Kaszeta <BR>
Published in Issue 27 of <i>Linux Gazette</i>, April 1998</H5></center>
<!--===================================================================-->
<P> <hr> <P>
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<H5>Copyright &copy; 1998 Specialized Systems Consultants, Inc.<br>
For information regarding copying and distribution of this material see the
<A HREF="../copying.html">Copying License</A>.</H5>
</center>
<P> <hr> <P>
<H3>Contents:</H3>
<ul>
<li><a HREF="./lg_backpage27.html#authors">About This Month's Authors</a>
<li><a HREF="./lg_backpage27.html#notlinux">Not Linux</a>
</ul>
<a name="authors"></a>
<P> <HR> <P>
<!--======================================================================-->
<center><H3> About This Month's Authors </H3></center>
<P> <HR> <P>
<!--======================================================================-->
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Murray Adelman</H4>
Murray is an academic mathematician; trained at the University of
Pennsylvania and teaching at Macquarie University in Sydney Australia
for the last twenty odd years. At a time when UNIX was new to our
department he stumbled across the Berkely User Supplementary Documents
and got interested in troff. He also vowed to save up and get a UNIX
system of his own. Linux saved him from the saving up part.
In his professional
work he has used mostly TeX, but maintains an interest in markup
languages in general, including SGML.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Larry Ayers</H4>
Larry lives on a small farm
in northern Missouri, where he is currently engaged in building a
timber-frame house for his family. He operates a portable band-saw mill,
does general woodworking, plays the fiddle and searches for rare
prairie plants, as well as growing shiitake mushrooms. He is also
struggling with configuring a Usenet news server for his local ISP.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Jim Dennis</H4>
Jim
is the proprietor of <A href="http://www.starshine.org">
Starshine Technical Services</A>.
His professional experience includes work in the technical
support, quality assurance, and information services (MIS)
departments of software companies like
<A href="http://www.quarterdeck.com"> Quarterdeck</A>,
<A href="http://www.symantec.com"> Symantec/
Peter Norton Group</A>, and
<A href="http://www.mcafee.com"> McAfee Associates</A> -- as well as
positions (field service rep) with smaller VAR's.
He's been using Linux since version 0.99p10 and is an active
participant on an ever-changing list of mailing lists and
newsgroups. He's just started collaborating on the 2nd Edition
for a book on Unix systems administration.
Jim is an avid science fiction fan -- and was
married at the World Science Fiction Convention in Anaheim.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Chris DiBona</H4>
Chris is a computer security specialist for StrongCrypto Inc. He
can be reached at chris@dibona.com. His personal web site is located at
http://www.dibona.com/.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">John M. Fisk</H4>
John is most noteworthy as the former editor of the <I>Linux Gazette</I>.
After three years as a General Surgery resident and
Research Fellow at the Vanderbilt University Medical Center,
John decided to &quot:hang up the stethoscope&quot:, and pursue a
career in Medical Information Management. He's currently a full
time student at the Middle Tennessee State University and hopes
to complete a graduate degree in Computer Science before
entering a Medical Informatics Fellowship. In his dwindling
free time he and his wife Faith enjoy hiking and camping in
Tennessee's beautiful Great Smoky Mountains. He has been an avid Linux fan,
since his first Slackware 2.0.0 installation a year and a half
ago.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Michael J. Hammel</H4>
Michael
is a transient software engineer with a background in
everything from data communications to GUI development to Interactive Cable
systems--all based in Unix. His interests outside of computers
include 5K/10K races, skiing, Thai food and gardening. He suggests if you
have any serious interest in finding out more about him, you visit his home
pages at http://www.csn.net/~mjhammel. You'll find out more
there than you really wanted to know.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Clint Jeffery</H4>
Clint is an assistant professor in the Division of Computer Science
at the University of Texas at San Antonio. He writes and teaches about
program execution monitoring, visualization, programming languages, and
software engineering. Contact him at
<a href="mailto:jeffery@cs.utsa.edu">jeffery@cs.utsa.edu</a> or read about
his research at
<a href="http://www.cs.utsa.edu/faculty/jeffery.html">http://www.cs.utsa.edu/faculty/jeffery.html</a>
He received his Ph.D. degree from the University of Arizona.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Richard Kaszeta</H4>
Richard is currently both a Unix Systems Administrator and a
PhD Student in the Mechanical Engineering Department of the University
of Minnesota, and currently administers more than 25 Linux machines
running Debian Linux. In addition to Linux, his hobbies include scuba
diving, ultimate frisbee, and cooking. You can visit his home page at
http://www.menet.umn.edu/~kaszeta.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">John Kodis</H4>
John has been involved in a wide range of scientific and
real-time software development efforts. He is currently the software
development manager for a large satellite image ingest, archive,
processing, and distribution system. He enjoys tinkering with Linux,
writing Perl, playing with his two kids, and trying to keep pace with
the rapid growth of the Gnome project.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">John Little</H4>
John, who worked for Sun for nine years, is from the U.K., lives
in Japan and works in Tokyo for an American company. He wears a range
of increasingly bizarre hats in an (mostly futile) effort to hide his
incipient baldness. He can be reached by e-mail at gaijin@pobox.com.
<p>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Eric Marsden</H4>
<a href="http://www.chez.com/emarsden/">Eric</a> is studying computer
science in Toulouse, France, and is a member of the local Linux Users
Group. He enjoys programming, cycling and Led Zeppelin. He admits to
once having owned a Macintosh, but denies any connection with the the
<a href="http://locke.ccil.org/~esr/ecsl/">Eric Conspiracy Secret
Labs</a>.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Shamim Mohamed</H4>
Shamim met Unix in 1983 and was introduced to Linux
at version 0.99 pl12. He is the author of Icon's POSIX interface and
produced the linux distributions described in this article.
These days he is a Silicon Valley polymath and
factotum, and an instrument rated pilot flying taildraggers. He's at
<a href="mailto:spm@drones.com">spm@drones.com</a> |
<a href="http://www.drones.com/shamim/">http://www.drones.com/shamim/</a>.
He received his Ph.D. degree from the University of Arizona.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Oliver M&uuml;ller</H4>
Oliver works
as programmer and is principal of a software developing firm. He is also
author and writes for several computer magazines and book publishers. His
email address is ogmueller@t-online.de.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Kirk Petersen</H4>
Kirk is a recent graduate of The Evergreen State College
and is working at NOAA in Seattle. He spends his spare time working on
various Linux software projects. E-mail him at kirk@muppetlabs.com or
check out his web page at http://www.muppetlabs.com/~kirk/.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Dave Wagle</H4>
Dave's a slightly quarky theology graduate student who has made a living
for the last 10 years developing, deploying, supporting and otherwise
wrestling with Unix and relational databases. He's married, has 2
kids, and an odd fondness for Kierkegaard. Write him at: davew@cloudnet.com.
<a name="notlinux"></a>
<P> <hr> <P>
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<center><H3> Not Linux </H3></center>
<P> <HR> <P>
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<P>
Thanks to all our authors, not just the ones above, but also those who wrote
giving us their tips and tricks and making suggestions. Thanks also to our
new mirror sites.
<P>
This month we say good-bye to our "Weekend Mechanic", John Fisk. John began
<I>Linux Gazette</I> as a learning project for himself, never dreaming how
popular it would become with the Linux community. When he turned <I>LG</I>
over to SSC, I was very pleased he planned to continue writing for
<I>LG</I>. I appreciate all of
John's contributions and will miss having his column in our pages. I
know you will too.
<P>
Bye, John, keep having fun!
<P> <hr> <P>
<A HREF="http://www.ssc.com/ssc/Employees/Margie/margie.html">
Marjorie L. Richardson</A> <br>
Editor, <A HREF="http://www.linuxgazette.com/"><i>Linux Gazette</i></A>, <A
HREF="mailto:gazette@ssc.com">gazette@ssc.com</a>
<P> <HR> <P>
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<I>Linux Gazette</I> Issue 27, April 1998,
<A HREF="http://www.linuxgazette.com/">http://www.linuxgazette.com</A><BR>
This page written and maintained by the Editor of <I>Linux Gazette</I>,
<A HREF="mailto: gazette@ssc.com"> gazette@ssc.com</A>
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