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<H5>Copyright &copy; 1996-97 Specialized Systems Consultants, Inc.
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<H1>Welcome to Linux Gazette!<img src="../gx/tm.gif" alt="(tm)"></H1>
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<H5>Copyright &copy; 1997 Specialized Systems Consultants, Inc. <BR>
For information regarding copying and distribution of this material see the
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<P> <HR> <P>
<!--=================================================================-->
<center><H1>Table of Contents <BR> May 1997 Issue #17</H1></center>
<P> <HR> <P>
<table><tr>
<td rowspan=3>
<UL>
<LI><A HREF="../index.html">The Front Page</A>
<LI><A HREF="./lg_mail17.html">The MailBag</A>
<ul>
<li><a HREF="./lg_mail17.html#help">Help Wanted -- Article Ideas</a>
<li><a HREF="./lg_mail17.html#gen">General Mail</a>
</ul>
<LI><A HREF="./lg_tips17.html">More 2 Cent Tips</A>
<ul>
<li><a HREF="./lg_tips17.html#Xlimitation">X Limitation to 8 Bit Color</a>
<li><a HREF="./lg_tips17.html#blank">Screen Blanking Under X</a>
<li><a HREF="./lg_tips17.html#double">Doubleclick Internet User
Profiles</a>
<li><a HREF="./lg_tips17.html#mount">How to Mount/Unmount For Users</a>
<li><a HREF="./lg_tips17.html#zprotocol">File Transfer With the z Protocol
<li><a HREF="./lg_tips17.html#commands">Using ftp Commands in Shellscript</a>
<li><a HREF="./lg_tips17.html#asciiart">ASCII-Artwork Translator</a>
<li><a HREF="./lg_tips17.html#graphic">Including Graphics in Linuxdoc SGML</a>
<li><a HREF="./lg_tips17.html#xconfig">X Configuration Issues</a>
<li><a HREF="./lg_tips17.html#display">Multiple X Displays</a>
<li><a HREF="./lg_tips17.html#colordp">Color Depths with X</a>
<li><a HREF="./lg_tips17.html#boot">Figuring Out the Boot Process</a>
<li><a HREF="./lg_tips17.html#ftp">ftping Home</a>
</ul>
<LI><A HREF="./lg_bytes17.html">News Bytes</A>
<ul>
<li><a HREF="./lg_bytes17.html#general">News in General</a>
<li><a HREF="./lg_bytes17.html#software">Software Announcements</a>
</ul>
<LI><A HREF="./answer.html">The Answer Guy</A>, by James T. Dennis
<ul>
<li><a HREF="./answer.html#fs">fs's</a>
<li><a HREF="./answer.html#unix">Linux/Unix Emulator</a>
<li><a HREF="./answer.html#vidX">Using X With 2 Monitors and 2 Video
Cards</a>
<li><a HREF="./answer.html#host">Virtual Hosting</a>
<li><a HREF="./answer.html#response">Response from Weitse Venema</a>
<li><a HREF="./answer.html#file">Automatic File Transfer</a>
<li><a HREF="./answer.html#ftpd">Installing wu-ftpd on a Linux Box</a>
<li><a HREF="./answer.html#boot">Trying to Boot a Laptop</a>
<li><a HREF="./answer.html#zmode">zmodem Reply</a>
<li><a HREF="./answer.html#start">StartX</a>
<li><a HREF="./answer.html#imap">IMAP and Linux</a>
<li><a HREF="./answer.html#imap2">IMAP Again</a>
<li><a HREF="./answer.html#uucp">UUCP Questions</a>
<li><a HREF="./answer.html#flops">Using MS-DOS Floppies</a>
<li><a HREF="./answer.html#inetd">inetd Questions</a>
<li><a HREF="./answer.html#modem">Navas Modem FAQ</a>
<li><a HREF="./answer.html#modem2">Setting Up a Modem</a>
<li><a HREF="./answer.html#userid">User Identification</a>
<li><a HREF="./answer.html#duplic">Duplicating a Linux Installed HD</a>
</ul>
<LI><A HREF="./clueless.html">Clueless at the Prompt: A Column for
New Users</A>, by Mike List
<LI><A HREF="./dotfile.html">The Dotfile Generator</A>, by Jesper Pedersen
<LI><A HREF="./gm.html">Graphics Muse</A>, by Michael J. Hammel
<LI><A HREF="./kandinsky.html">Kandinsky</A>, by Jeff Hohensee
<LI><A HREF="./expo.html">Linux Expo 1997</A>, by Jon "maddog" Hall
<LI><A HREF="./raid.html">Linux Raid Functions</A>, by Jay Painter
<LI><A HREF="./enl.html">New Release Reviews</A>, by Larry Ayers
<ul>
<LI><A HREF="./enl.html">A Fresh Beginning: The Enlightment Window Manager</A>
<LI><A HREF="./cthugha.html">Visual Music: The Linux Port of Cthugha</A>
<LI><A HREF="./updates_17.html">Updates & Corrections</A>
</ul>
<LI><A HREF="./slackware.html">Slackware Linux Installation & Getting Started</A>, by
Sean Dreilinger
<LI><A HREF="./texas.html">Texas Linux Installation Project</A>, by
Kendall G. Clark
<LI><A HREF="./lg_backpage17.html">The Back Page</A>
<ul>
<li><a HREF="./lg_backpage17.html#authors">About This Month's Authors</a>
<li><a HREF="./lg_backpage17.html#notlinux">Not Linux</a>
</ul>
</UL>
</td>
<td align=center>
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</a>
</td>
</tr><tr>
<td align=center>
<A HREF="answer.html">
<img src="../gx/wizard2.gif" border=0 alt="">
</a>
<p>
<A HREF="answer.html"><i>The Answer Guy</i></a> <BR>
</td>
</tr><tr>
<td align=center>
<!--<A HREF="wkndmech.html"> -->
<img src="../gx/fisk/attndant.gif" border=0 alt="">
<!--</a> -->
<p>
<!--<A HREF="wkndmech.html"><i>Weekend Mechanic</i></a> <BR> -->
Weekend Mechanic will return next month.
</td>
</tr></table>
<P> <HR><P>
<!--=============================================================-->
<A HREF="./issue17.txt">TWDT 1 (text)</A><BR>
<A HREF="./issue17.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>&quot;Linux Gazette...<I>making Linux just a little more fun!</I>&quot;</H4>
<HR>
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<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_mail17.html#help">Help Wanted -- Article Ideas</a>
<li><a HREF="./lg_mail17.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>
<!--====================================================================-->
<center><IMG ALT=" " SRC="./gx/iwantyou.gif"></center>
<P>
The last couple of months have been rather light on articles. It's been
helpful to have the new chapters for <I>Linux Installation and Getting Starting</I>
to include. So all you budding authors and Linux users out there,
send me your stuff. Don't depend on our regular authors to fill the gap. We
want to hear about all the neat tips and tricks you've found, as well as
all the neat applications your are writing or working with. --Editor
<P> <P> <P> <P>
<P> <HR> <P>
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Sat Apr 19 07:29:14 1997<br>
Subject: <b>Searching for Information On Newsgroups</b><br>
From: Roman, <a href="mailto:Roman@pussycat.ping.de">Roman@pussycat.ping.de</a><br>
<p>Hi folks!
<p>I'm installing a very small news- and email system at my local
university (peolpe there are studying arts, so there's no one to help me
with this). I set up one computer with Linux 2.0.29 which is permanently
connected to the 'internet' via ethernet. Then I want to connect a
second PC which is installed in the hallway via nullmodem-cable for all
the students to write and receive eMail. But the problem now is, that
the provider (another part of the university) doesn't give us access to
the newsgroups, so I want to set up at least some local newsgroups on
this Linux-station.
<p>But I just can't seem to find any documentation explaining how to set up
local newsgroups. smtpd and nntpd are running, but the manpages won't
tell anything about how to set up ng's (forgive me if I'm just too blind
or stupid to find the obvious source of information).
<p>So I don't want to bother you explaining me how to accomplish this task,
but perhaps someone can at least tell me where to find the desired
information.
<p>Best regards,
Roman.
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Thu Apr 24 11:44:40 1997 <br>
Subject: <b>VGA_16 Server</b><br>
From: Javier Viscain
<p> Congratulations for the aim and contents of the Gazette.
Here is an issue I've never seen addressed: the VGA_16
server maintains two monitors (the second monochrome with an
Hercules card) but what only works is the mouse movement, which
moves out of left and right to the other monitor, and console
switching. No window on the monochrome gets focus. Things that
moreless appear on the monochrome but don't work:
<ul>
<li> Xeyes: both eyes are displayed, but the inner dots
appear as moving diagonal lines out of the eyes.
<li> Xterm: an useless box appears.
Xterm with exec: say "xterm -display xxx:0.1 -exec top &"
appears as an xterm box with the letters from "top" without any
order, in and out from the xterm box.
<li> Xload: the "load" and letters appear out of the box.
</ul>
<p> I think that the hardware absolute addressing is the
normal VGA one (0A0000 to 0AFFFF) and 64K for the Hercules
(0B0000 to 0BFFFF), which is correct.
In adition, this server and the mono server are very
buggy when with only the Hercules.
<p> Any easy solution, or is it that this configuration has not
been debugged?
<p>
TIA, Javier Vizcaino, Madrid, Spain.
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Sun 6 Apr 1997 11:54:42 -0400<br>
Subject: <b>Initilation Files</b><br>
From Karl Easterly <a
href="mailto:bigtexan@mindspring.com">bigtexan@mindspring.com</a><br>
As an article Idea, I think an overview of the major boot scripts would =
be helpful. The overview could include an objective view of the =
locations, functions, and nifty "tips and tricks" or such. Also, links =
to how-toos for each script would future simplify the learning curve for =
new users.
<p>Another idea would be to do a chronological installations and =
customization series of articles. Granted, hardware diversity might be =
a problem and could possibly be subverted by starting the series as =
though a working installation of Linux has already been installed. It =
would proceed as a rough idea like this.
<ol>
<li>Booting customization and kernel rebuilding.
<li>Xwin customization, to include the type of activities one =
would do in Win95 desktop setup.
<li>Getting dialup connectivity to work.
<li>Getting network connectivity to work.
</ol>
<p>These are just stabs at a scheme, the actual order would have to be =
hammered out before the series started, but in general, would be helpful =
to have a step by step issue oriented series of articles concerning the =
setup and customization of any linux installation.
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Sat, 1 Mar 1997 15:39:10 -0500<br>
Subject: <b>Ideas for Beginners</b><br>
From: stephen jarvis <a href="mailto:106363.2642@compuserve.com">106363.2642@compuserve.com</a>
<p>Hello
<p> I am 'the' absolute beginner.I have had a copy of Linux Slackware
and a copy of "Linux configuration and installation " by P Volkerding et al
for about two weeks.Prior to this I had dabbled at dos and wondered(?) at
windows.But when I heard about Linux in a magazine it occured to me that it
might be fun to have a go.And indeed it has been.
<p> The only problem I have had is with regard to the man pages. In
general they are technical to a degree that while appropriate for those who
can follow the argument from end to end,are pretty debilitating for the
newbie like me.Indeed I don't always get to the end.
<p> Perseverence will no doubt pay off and I have expanded my
collection of books already,to take advantage of the possibility of
learning something about programming on Linux.But then I have always had
the kind of curiousity that,while not enough to kill the cat,is enough to
keep me in the book shop.The point I think is that the man pages themselves
are a bit of a barrier to the wider useage of Linux.
<p> No doubt others would say the detail and technical clout of this
source of information is needed for those who want to make serious use of
Linux.But not everyone who wants to escape from the soporific influence of
Microsoft is that demanding or that knowledgeable.I think someone needs to
pitch things at the introductory level.In the realms of 'this will get it
going'and 'try this out'.Merely a more chatty approach would help remove
the shiney armour of incomprehensibilty some pages deploy.
<p> If this sounds a little unfair to the many people who have compiled
,man pages it is most definitley not meant to be.There is a need for
accurate and complete information especially as Linux is a cooperative
venture and everyone needs to have a common root of information.The
question is how can the benefits of Linux be made widely known to people
outside the existing network.What will grab their attention and take the
gleam off Windows 95?Something more open to a wider audience perhaps.
<p> This does not have to be completely bland and overly simple just in
the range of every day usage.An approach that does not assume that everyone
reading knows the meaning of every term on the page.People need an
introduction to the language of Linux in the way that you might learn
French or English.Start with very basic things and build up in stages.Don't
launch straight into 'How To Compile Your Kernal '.Ok thats important ,but
I am sure most people still think a kernal is what you find inside a nut.I
hope you are getting the general idea.
<p> What us new people need is probably a collection of basic texts
each about the length of a several page magazine article.Hopefully they
would cover the things that a hardend Linux user would be embarrassed to
ask about.'The kernal for beginners'.'Great now I can ask what it really
is'.If this undertaking was started then I am sure that the end product of
a few months could be published as a small book.Maybe you could publish
it.I think there is a potential market.Many magazines recently covered the
subject of Linux.That's how I got the bug.
<p> Now it's true there are books already that cover Linux but there
are not many on line man pages or magazine articles that give the beginner
the feeling that they can actually get their system up and running
easily.So if you really want to publish articles for absolute beginners
bear in mind the kind of language that is used.
<p> Regards
Steve Jarvis
<p>ps.. here's some ideas ' What is the kernal','The basic commands to get
around bash','What are disk partitions and why bother',' To Umsdos or not.
That's the question','Midnight Commander-an introduction','This is the
easiest editor anybody ever used(insert your choice)','A glossary of
general terms you'll find on a man page','These books are a good
read(assorted titles)'.'How to get around an info text with less than 20
pages of instructions','Why the idea of a free and open o/s matters','X is
not a horror film'.
<p>Maybe these are a bit daft but they'd get my attention.They are the sort of
things I'd like to know about.
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: 04 Apr 97 19:02:21 EST<br>
Subject: <b>Technical Support</b><br>
From: Dani Fricker <a href="mailto:101550.3160@CompuServe.COM">101550.3160@CompuServe.COM</a>
<p>first i wanna say thanx for the lj! great work and fun not even for linuxers!
i need your help. for some reasons i have to identify a user on my webserver by
his/her
ip-address. fact is that users logon comes from different physical machines.
that means
that i have to assign something like a virtual ip-address to a users log name.
something
like a reversal masquerading.
my ip-gateway connects my inner lan over two token ring network cards
(sorry, not my idea!) with the internet (lan <-> tr0 <-> tr1 <-> internet). the
masquerading forward roule of ipfwadm gives me the possibility to indicate a
source and
a destination address.
do you see a possibility for an 'address assignment' between the two interfaces?
if you
do please let me know.
<p>
dani fricker<br>
programmer<br>
zurich-switzerland
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Mon, 07 Apr 1997 03:01:17 -0500<br>
Subject:<b>HELP with Man Pages</b>
From: "Mauricio Naranjo N." <a href="mailto:davasgut@col2.telecom.com.co">davasgut@col2.telecom.com.co</a><br>
<p>Well, I have installed the linux toolkit / october 1996 and I have not
been able to install the man pages for commonly used commands like cat,
ls, and so on; instead I have installed the man pages for packages like,
fvwm, midnight commander, ....
<p> So, I installed man2.tgz, man3.tgz, manpgs.tgz, but I still have not
been able to get installed the whole support for man;
Can you tell me please, what's the matter????
Any kind of help would be great appreciated, and excuses for ignorance
but I am new at this OS (finally I found a true one)
<p>
Mao
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Mon, 7 Apr 1997 15:43:21 -0400 (EDT)<br>
Subject: <b>Port Mouse</b><br>
From: Jose, <a href="mailto:notDefined@novagate.com">notDefined@novagate.com</a><br>
<p>Hi,
Maybe you can help me with this. (I hope)
I switched motherboards, from a zeos pentium 90 that used a serial mouse to a
asus p/i-p55tvp4 motherboard that uses a port mouse.
And now I can't get x-windows to run.
Any ideas?
<p>
Jose
<a name="gen"></a>
<P> <hr> <P>
<!-- =================================================================== -->
<center><H3> General Mail </H3></center>
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Tue, 01 Apr 1997 04:26:04 -0600<br>
Subject: <b>Linux</b><br>
From: Tred Riggs <a href="mailto:tred@oak.sfasu.edu">tred@oak.sfasu.edu</a>
<p>I am a college student attending Stephen F. Austin State University. I
work in a Geographic Information Systems Laboratory (GIS) and we have
been just using AIX machines. Howerver we do have a full blown linux pc
and it is great. {Since then I stripped DOS off my PC and made me a
full blown linux box, which works wonderful. We were considering to
upgrade to all linux PC's in out lab because they were cheaper and
faster than the AIX boxes, but we ran into a problem. The Software we
need to run to make our GIS maps is not supported by ESRI, so we gave
them a call. This is what they told us:
<p>"Linux will not be a supported platform. They told me that product
ports are user driven and there is not enough users wanting this OS."
<p>I could not figure out how they could even say this when all you have to
do is get on the web and see millions of people using linux. So here is
what I want to happen. I need linux users to E-mail ESRI at
buspartners@esri.com and tell them that you use linux and that there are
many more people using linux too. ESRI needs to get there head out of
Microsofts world and see what is going on in the real world.
<p>Thanks for your time Linux Gazette,
<p>Tred Riggs
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Thu, 3 Apr 97 22:40:23 BST<br>
Subject:<b>http://www.ssc.com/lg/index.html</b><br>
From: Duncan Simpson <a href="mailto:dps@duncan.telstar.net">dps@duncan.telstar.net</a><br>
<p>Given Micro$oft's tag line of "Yet another Web server powered by NT" maybe we should
collect a list of people doing this sort of stuff on Linux. I can add 3 items myself
<a href="http://mail.telstar.net">http://mail.telstar.net</a> is powered by Linux
The telstar mail service described there is also powered by the same linux box
Astra has switch from NT to Linux for its radius server. (NT was just too expensive
and no better than Linux (Un*x)---the price diffrernece was *1000s* of pounds, each
about 1.5 $ US).
Both astra (and telstar.net) DNS servers are linux.
<p>If the stats show that Linux is more popular for comercial web servers than NT, this would
be something nice to be able to point out...
<p>Duncan (-:
<p>P.S. Any bets when Truetype fonts can be used for proper typesetiing. At present they
lack litagures (fl and various other items that are tradionally rendered as single
characters)?
<p>P.P.S. The use of the present tense (switch) is apt because the change is happening
now. (Despite a bug that is now not being exercised due to an attempt to eradicate it
mail.telstar.net is more reliable than any of various NT machines at handling mail).
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Fri, 04 Apr 1997 15:57:12 -0600<br>
Subject: <b>Re: How to ftp Back Home</b><br>
From: James Stansell <a href="mailto:james.stansell@wcom.com">james.stansell@wcom.com</a><br>
<p>The ifconfig command works, and may be the most authoritative on the
subject (except I believe the PPP log also contains your current IP),
but the ifconfig command returns a ton more information than I want.
<p>So I ask my machine at work who I am:
<pre>who am i
stansell ttyp6 Apr 4 15:51 (206.125.79.118)
</pre>
<p>I've inserted your example IP address where my actual address
showed up. If the DNS at work does happen to know a name for my
address, then it shows up instead of the IP.
<p>
--james
<P> <HR> <P>
<!--====================================================================-->
<IMG ALT=" " SRC="../gx/envelope.gif">
Date: Thu, 10 Apr 1997 17:08:38 -0500<br>
Subject: <b>Re:GV article</b><br>
From: Larry Ayers <a href="mailto:ayers@vax2.rainis.net">ayers@vax2.rainis.net</a><br>
To: Geoffrey Leach <a href="mailto:geoffrey@iname.com">geoffrey@iname.com</a><br>
Sorry the URL didn't work for you; I recently got an email
message from Helmut Geyer, the maintainer of the Debian GV
version and he included a URL for a new GV home-page:
<a href="http://wwwthep.physik.uni-mainz.de/~plass/gv/">http://wwwthep.physik.uni-mainz.de/~plass/gv/</a>
<p> The Debian version is in the /text section of the /i386 binary
directory of any Debian mirror. Shouldn't be too hard to find.
<p>Good luck!
<p> Larry Ayers
<P> <hr> <P>
<!--================================================================-->
<center>Published in Linux Gazette Issue 17, May 1997</center>
<!--====================================================================-->
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<h5>This page written and maintained by the Assistant Editor of <I>Linux Gazette</I>,
<A HREF="mailto: gazette@ssc.com">gazette@ssc.com</A><BR>
Copyright &copy; 1997 Specialized Systems Consultants, Inc. </H5>
<P>
<H4>&quot;Linux Gazette...<I>making Linux just a little more fun!</I>
&quot;</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_tips17.html#Xlimitation">X Limitation to 8 Bit Color</a>
<li><a HREF="./lg_tips17.html#blank">Screen Blanking Under X</a>
<li><a HREF="./lg_tips17.html#double">Doubleclick Internet User
Profiles</a>
<li><a HREF="./lg_tips17.html#mount">How to Mount/Unmount For Users</a>
<li><a HREF="./lg_tips17.html#zprotocol">File Transfer With the z Protocol
<li><a HREF="./lg_tips17.html#commands">Using ftp Commands in Shellscript</a>
<li><a HREF="./lg_tips17.html#asciiart">ASCII-Artwork Translator</a>
<li><a HREF="./lg_tips17.html#graphic">Including Graphics in Linuxdoc SGML</a>
<li><a HREF="./lg_tips17.html#xconfig">X Configuration Issues</a>
<li><a HREF="./lg_tips17.html#display">Multiple X Displays</a>
<li><a HREF="./lg_tips17.html#colordp">Color Depths with X</a>
<li><a HREF="./lg_tips17.html#boot">Figuring Out the Boot Process</a>
<li><a HREF="./lg_tips17.html#ftp">ftping Home</a>
</ul>
<P> <hr> <P>
<!--================================================================-->
<a name="Xlimitation"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
X Limitation to 8 Bit Color
</H3>
<P>
From: Gary Masters <a href="mailto:="mailto:gmasters@devcg.denver.co.us">gmasters@devcg.denver.co.us</a>
<p>I read your question in Linux Gazette regarding an X limitation to 8 bit
color when the system has more than 14 megs of RAM.
Where did you find that information? I ask because my system has 24 megs
of RAM, and I run 16 bit color all the time.
One difference between our systems is that I am using a Diamond Stealth 64
video card.
<p>The place I tell X to run in 16 bit mode is in the file
/usr/X11R6/bin/startx. There is a line in this file that begins with
<tt>serverargs</tt>. I get 16 bit mode by giving "-bpp 16" as an argument in
this line (e.g. serverargs="-bpp 16").
<p>One problem I did have was that the OpenLook Window Manager (olwm) did not
like 16 bpp mode. I solved this by switching to the OpenLook Virtual
Window Manager (olvwm)[1]. I also had success using the Tab and FV Window
Managers (twm & fvwm) in 16 bpp mode.
<p>Coming from a SunOS background, I'm used to OpenLook.
<p>Gary Masters
<P> <hr> <P>
<!--================================================================-->
<a name="blank"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Screen Blanking Under X
</H3>
<P>
From: Gary Masters <a
href="mailto:gmasters@devcg.denver.co.us">gmasters@devcg.denver.co.us</a>
<p>I read your question in the Linux Gazette regarding unwanted screen
blanking under X after upgrading to a newer distribution of Linux. I had
the same frustration. Apparently the X servers included in the Xfree86
version distributed with current Linux distributions has screen blanking
compiled as a default behavior.
<p>This behavior can be controlled with the -s option to the server. Look in
the startx script for a line that begins with serverargs and add "-s 0".
This will disable the X screen blank.
<P>
Gary Masters
<P> <hr> <P>
<!--================================================================-->
<a name="double"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Doubleclick Internet User Profiles
</H3>
<P>
From: Kragen Javier Sittler <a href="mailto:kragen@pobox.com">kragen@pobox.com</a>
<p>Check out the description of what doubleclick.net does at
<a href="http://www.doubleclick.net/frames/adinfo/dartset.htm">http://www.doubleclick.net/frames/adinfo/dartset.htm</a>
<p>Then decide whether you want to be added to their database of Internet
user profiles. If not, you can use the script below; I run it in my
<pre>/etc/rc.d/rc.inet1</pre>. It prevents any DoubleClick banners from being
displayed, prevents any cookies from being set, and prevents DoubleClick
from collecting any data on you.
<p>It also does the same thing with linkexchange.com, because I find their
constant banners and requests for cookies annoying. If you'd prefer,
you can take out the linkexchange lines.
<p>However, this will also keep you from receiving *any* information from
doubleclick or linkexchange directly... so you can't visit their web
sites either.
<p>On my machine, I put the script in <pre>/etc/rc.d/rc.doubleclick</pre> and run
it from <pre>/etc/rc.d/rc.inet1</pre> at boot time, so I'm always protected from
DoubleClick.
<pre>
# Script begins below:
#!/bin/sh
# By Kragen Sitaker, 21 April 1997.
# Prevent any packets from reaching doubleclick.net
/sbin/route add -net 199.95.207.0 netmask 255.255.255.0 lo
/sbin/route add -net 199.95.208.0 netmask 255.255.255.0 lo
# And ad.linkexchange.com too!
/sbin/route add -net 204.71.189.0 netmask 255.255.255.0 lo
</pre>
<P> <hr> <P>
<!--================================================================-->
<a name="mount"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
How to Mount/Unmount For Users
</H3>
<P>
From: Kidong Lee <a href="mailto:kidong@shinbiro.com">kidong@shinbiro.com</a>
<p>When I mount/umount file, I have to login as root.
It's not convenient for me & other users.
but, I found the solution that user who is not root can do mount/umount
in mount man page.
<p>Take a look at /etc/fstab.
<pre>
# <device> <mountpoint> <filesystemtype> <options> <dump>
<fsckorder>
/dev/hdb /cdrom iso9660 ro,user 0 0
</pre>
<p>Note "user" in options field.
In options field, if you add "user", users can do mount/umount.
<P> <hr> <P>
<!--================================================================-->
<a name="zprotocol"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
File Transfer With the z Protocol
</H3>
<P>
From: Gregor Gerstmann, <a href="mailto:gerstman@tfh-berlin.de">gerstman@tfh-berlin.de</a>
<p>Regarding Linux Gazette issue16, April 1997, I have some remarks
regarding the article on file transfer with the z protocol:
'I type sz <filename> things go along fine, until about 40K
then I get a couple of different error messages....'
We have an internal modem with a transfer rate of 2880 cps on
the telephone line. My son has an account at a Berlin university
with a limited capacity of 5MB. We found the same error but not
limited to a special file size! During the night hours, between 1
and 5h local time, when telephone costs are lowest, we sometimes
transfered files up to 100KB without errors!
To avoid any errors at all, I limited the packages to 20 * 1024
= 20480 bytes, if a CRC occurs, transfer begins once more but with-
out timeout error, because the parcels are small. I use two proce-
dures: the first, Chop, generates another procedure that chops the
file to be transfered with the help of dd into packages and regu-
lates the transfer and removing of transfered packages. At home we
concatenate the packages again with cat ... ... > ... and everything
is ok. The last step could be done by a procedure too.
Of course, it is rather simple software, but it works until we
will use ISDN.
<p>
<pre>
first parameter - number of bytes
second - begin of output names, e.g. p1
third - name of file to be chopped
#!/bin/bash
echo "* Begin of procedure Chop *"
date
# rm alte Datei
if test -e /usr/TFH/EXAMPLE
then rm /usr/TFH/EXAMPLE
fi
# Test auf Parameter
if test $# -lt 3
then echo "Incorrect number of parameters !
Please repeat procedure call !"
echo "* End of procedure Chop (error) *"
exit 1
else echo "Call was ok"
fi
#
BY=$1
ANZZ=$[(($BY / 20480) + 1)]
quantity=$ANZZ
i=1
recs=0
while test "$i" -lt "$quantity"
do
echo dd if=$3 of=$2_$i bs=1024 skip=$recs count=20 >> /usr/TFH/EXAMPLE
echo sz $2_$i >> /usr/TFH/EXAMPLE
echo rm $2_$i >> /usr/TFH/EXAMPLE
i="`expr $i + 1`"
recs="`expr $recs + 20`"
done
echo dd if=$3 of=$2_$i bs=1024 skip=$recs >> /usr/TFH/EXAMPLE
echo sz $2_$i >> /usr/TFH/EXAMPLE
echo rm $2_$i >> /usr/TFH/EXAMPLE
#
echo "* End of procedure Chop (ok) *"
#
</pre>
<P> <hr> <P>
<!--================================================================-->
<a name="commands"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Using ftp Commands in Shellscript
</H3>
<P>
From: Walter Harms, <a href="mailto:Walter.Harms@Informatik.Uni-Oldenburg.DE">Walter.Harms@Informatik.Uni-Oldenburg.DE</a><br>
Using FTP as a shell-command with ftplib<br>
<p>Working on several different networks means that you always
need to copy your data from net to net. Most ppl use rcp but like most SysOps
I found this to be a terrible security hole. So as I started this job my first
business was to rewrite several scripts that were using rsh,rcp etc.
I replaced them with an ftp based script ftp - &ltinput&gt out 2&gt out.err.
It's easy to
see that this was not a good idea because ftp was not intended as shell-commando
like cp,mv and the other guys. So I was happy to find the ftplib on a
linux-CD. It's a nice lib that I used to build cmds like ftpmv, ftpcp, ftprm..
This made my scripts much slimmer and simpler. I have some terrible
copy-scripts running but no problems copying on different systems
like Ultrix or AIX.
<p>Example using ftpget (from the ftplib Author Thomas Pfau)
<pre>ftpget sunsite.unc.edu -r /pub/Linux ls-lR.gz</pre>
This command reads the file <pre>/pub/Linux/ls-lR.gz from sunsite.unc.edu</pre>
Likewise there are other commands with the lib: ftpdir ,ftpsend, ftprm
<p>Who needs ftplib?<br>
Everybody tired of typing ftp... every evening to
get the latest patches or whatever. Everyone who is regularly copying
with ftp the same Datafiles.
<p>Why use ftplib?<br>
Of course you can add it to you own application but more experienced users don't
have to use these r-commands anymore. An ftpd is available for the
majority of systems so it is easier to access more of them.
<p>Any drawbacks?<br>
Of course, for any ftp session you need a user/paswdr. I copy into
public area using anonymous/email@ others will need to surly a
password at login, what is not very useful for regular jobs or
you have to use some kind of public login but still I think it's
easier and better to use than the r-cmds.
<p>
-- walter
<P> <hr> <P>
<!--================================================================-->
<a name="asciiart"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
ACSII-Artwork Translator
</H3>
<P>
Here is something interesting which you might consider for publication.
It is a short program written in LEX and C, which takes ASCII-Artwork
and translates it into HTML 3.0 compliant table data.
It is a pretty interesting idea, and as far as I know, I'm the first
person to try something like this, or automate the process.
The translator (a2t) has a few options:
<p>
<ul>
<li>-x : reverse the output
This is because some ASCII-Artwork is meant to be seen as
black on white and not white on black.
<li>-r value
<li>-g value
<li>-b value
Sets constant r,g, and or b, rgb values, so that the resulting
"grayscale" output can be altered to shades of a color.
<li>-w value
Sets the width of the resulting table.
</ul>
<p>The program was completed just today, so it is very new. I've
released it under the GNU license agreement.
<p>For some examples of the output generated by a2t, see:
<a href="http://wilkes.edu/~pkeane">http://wilkes.edu/~pkeane</a><br>
I think you'll find the results to be pretty amusing, and slightly
more interesting than the usual bag of HTML table-tricks.
<p>
Enjoy--
Patrick
<pre>
%{
/* Ascii-to-Table version 2.0
**
** A conversion utility to convert gifscii type ASCII-Artwork into
** grayscale HTML 3.0 compliant html documents using tables.
**
** Copyright(C) 1997 by Patrick J.M. Keane -- All rights reserved.
** (pkeane@wilkes.edu)
**
** This program is free software; you can redistribute it and/or modify
** it under the terms of the GNU General Public License as published by
** the Free Software Foundation; either version 2 of the License, or
** (at your option) any later version.
**
** This program is distributed in the hope that it will be useful,
** but WITHOUT ANY WARRANTY; without even the implied warranty of
** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
** GNU General Public License for more details.
**
** You should have received a copy of the GNU General Public License
** along with this program; if not, write to the Free Software
** Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
**
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
char shade1[4], shade2[4], shade3[4] ;
int reverse=0, widthset=0, width=0 ;
int shade1set=0, shade2set=0, shade3set=0 ;
void maketd(const char *value) {
printf("<td bgcolor=") ;
printf("#%s%s%s>",
((shade1set==0) ? value : shade1),
((shade2set==0) ? value : shade2),
((shade3set==0) ? value : shade3)) ;
printf("<font size=0>&nbsp;</font></td>") ;
}
main(int argc, char *argv[]) {
int c;
extern int optind;
extern char *optarg;
extern int opterr;
while ((c = getopt(argc, argv, "w:r:g:b:xh")) != EOF) {
switch (c) {
case 'x':
reverse = 1 ;
break;
case 'h':
fprintf(stderr, "Usage:\n\tcat asciifile | a2t [-h] [-x] [-[rgb] value] [-w width] > document.html\n\n") ;
fprintf(stderr, "\t-h : This help screen\n") ;
fprintf(stderr, "\t-x : Reverse output\n") ;
fprintf(stderr, "\t-r value : Constant R <R>GB value\n") ;
fprintf(stderr, "\t-g value : Constant G R<G>B value\n") ;
fprintf(stderr, "\t-b value : Constant B RG&lt;B&gt; value\n") ;
fprintf(stderr, "\t-w value : Set width of output table\n") ;
exit(0) ;
break;
case 'r':
shade1set = 1 ;
strcpy(shade1, optarg) ;
break ;
case 'g':
shade2set = 1 ;
strcpy(shade2, optarg) ;
break ;
case 'b':
shade3set = 1 ;
strcpy(shade3, optarg) ;
break ;
case 'w':
widthset = 1 ;
width = atoi(optarg) ;
break ;
default:
fprintf(stderr, "Bad option: %c\n", c);
exit(1) ;
break;
}
}
printf ("<title>Table Art!</title>\n") ;
printf ("<!---Generated by a2t version 2.0 by Patrick Keane--->\n") ;
printf ("<!---pkeane@wilkes.edu--->\n") ;
printf ("<body bgcolor=black text=white>\n") ;
printf ("<center>\n") ;
printf ("<table border=0 cellpadding=0 cellspacing=1") ;
if (widthset)
printf(" width=%d>", width) ;
else
printf(">") ;
printf ("<tr>\n") ;
yylex() ;
printf("</table></center>\n") ;
}
%}
%option yylineno
ws [ ]*
%%
"$"|"@" { (reverse) ? maketd("00") : maketd("ff") ; }
"W"|"M" { (reverse) ? maketd("20") : maketd("f7") ; }
"B"|"%"|"8"|"&" { (reverse) ? maketd("20") : maketd("f0") ; }
"#"|"*"|"9"|"6"|"H" { (reverse) ? maketd("20") : maketd("e7") ; }
"o"|"h"|"k" { (reverse) ? maketd("27") : maketd("e0") ; }
"4"|"5"|"S"|"K" { (reverse) ? maketd("30") : maketd("d7") ; }
"a"|"e"|"s" { (reverse) ? maketd("37") : maketd("d0") ; }
"b"|"d"|"p"|"q" { (reverse) ? maketd("40") : maketd("c7") ; }
"w"|"m"|"3" { (reverse) ? maketd("47") : maketd("b7") ; }
"z"|"O"|"0"|"Q" { (reverse) ? maketd("50") : maketd("b0") ; }
"L"|"G"|"D"|"C"|"2" { (reverse) ? maketd("57") : maketd("a7") ; }
"R"|"E"|"U"|"X" { (reverse) ? maketd("60") : maketd("a0") ; }
"N"|"A"|"Y"|"P" { (reverse) ? maketd("67") : maketd("97") ; }
"F"|"J"|"Z"|"z"|"c" { (reverse) ? maketd("70") : maketd("90") ; }
"g"|"y" { (reverse) ? maketd("77") : maketd("85") ; }
"x"|"v"|"u"|"n" { (reverse) ? maketd("80") : maketd("80") ; }
"="|"I"|"r"|"j"|"T" { (reverse) ? maketd("87") : maketd("77") ; }
"f"|"t" { (reverse) ? maketd("90") : maketd("70") ; }
"|"|"?"|"V"|"/"|"\\"|"7" { (reverse) ? maketd("97") : maketd("67") ; }
"["|"]"|"{"|"}" { (reverse) ? maketd("a0") : maketd("60") ; }
"<"|">"|"("|")" { (reverse) ? maketd("c5") : maketd("50") ; }
"i"|"l"|"1"|"|"|"!" { (reverse) ? maketd("d0") : maketd("40") ; }
":"|";"|"+"|"~" { (reverse) ? maketd("e0") : maketd("30") ; }
"^"|"\"" { (reverse) ? maketd("e7") : maketd("27") ; }
"-"|"_" { (reverse) ? maketd("ff") : maketd("20") ; }
"'"|"`" { (reverse) ? maketd("ff") : maketd("20") ; }
"."|"," { (reverse) ? maketd("ff") : maketd("20") ; }
{ws}"\n" { printf("<td bgcolor=black><font size=0>&nbsp;") ;
printf("</font></td></tr>\n") ; }
" " { maketd("00") ; }
. { fprintf(stderr, "Warning: Character %s is not recognized.\n",
yytext) ;
fprintf(stderr, "Choosing a medium color!\n") ;
maketd("97") ; }
%%
void yyerror(char *msg) {
fprintf(stderr, "^GError :\tLine %d: %s at '%s'\n", yylineno, msg, yytext) ;
}
int yywrap() {
return (1);
}
</pre>
<P> <hr> <P>
<!--================================================================-->
<a name="graphic"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Including Graphics in Linuxdoc SGML
</H3>
<P>
From: Martin Michlmayr<a href="mailto:tbm@cyrius.com">tbm@cyrius.com</a><br>
Date: Thu, Apr 17, 1997 at 07:48:19PM +0200<br>
You can already include PostScript images in Linuxdoc-SGML which
will get included in TeX output (and consequently in DVI and
PostScript). Linuxdoc-SGML doesn't support images for HTML,
however.
<p>
An example:
<pre>
<figure>
<eps file = "neuro">
<caption><label id = "decade">
Decade of the brain
</figure>
</pre>
<p>You can make references to the figure with <ref id="decade">
<p>PostScript is already supported and the developer version of SGML-Tools
(the successor of Linuxdoc-SGML) now supports HTML as well. You
can specify a PostScript and a GIF file and depending on the output
(TeX or HTML) the respective image will be included.
<P> <hr> <P>
<!--================================================================-->
<a name="xconfig"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
X Configuration Issues
</H3>
<P>
Date: Wed Apr 2 12:15:54 1997<BR>
From: Michael J. Hammel, <a href="mailto:mjhammel@emass.com">mjhammel@emass.com</a>
<p>If you get sufficiently tweaked by the X monitor config problems,
I
suggest X Inside's AcceleratedX package. Its much simpler to configure
than the XFree package for both cards and monitors. I used to work
for them, but haven't in over a year. I still use their package because
its the easiest to handle all the video card/monitor details.
<p>BTW, the monitor setup is menu based. If your monitor is not listed
you can just use one of the multisync if single frequency generic
configs. No dot clocks, but you do need to no your monitors frequency
capabilities. These should be listed in the monitors cdocumetntation.
<p>The package is a commercial distribution and runs about $100 (last time
I checked). They change their name to Xi Graphics recently and the domain
for xinside.com might not be working right now. Try <a
href="http://www.xig.com">http://www.xig.com</a>.
<p>--
Michael J. Hammel
<P> <hr> <P>
<!--================================================================-->
<a name="display"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Multiple X Displays
</H3>
<P>
Date: Wed Apr 2 13:38:08 1997<br>
From: Michael J. Hammel <a href="mailto:mjhammel@emass.com">mjhammel@emass.com</a><BR>
<p>Setting up the software is probably fairly straight forward. I've
never used MetroX (I use AcceleratedX instead), however. Basically
you'll have two choices:
<ol>
<li> Multiple displays (host:0.0 and host:1.0)
<li> Multiple screens of the same display (host:0.0 and host:0.1)
</ol>
<p>The second choice is the one you need if you want to move the mouse
between the two monitors - like when the mouse goes past the right edge
of the first monitor it shows up on the left edge of the second monitor.
You'll have to check with Metro to find out which of these options is
supported and how to configure for it.
<p>The hardware problem is tougher. The problem lies in the fact that PC's
were not originally designed with the idea that multiple display
adapters would be installed. The BIOS looks for an adapter at certain
locations (IRQ, I/O address) and, unless the second card is configurable
to some other address, the system will find multiple cards. What
happens next is in-determinant. Some systems won't boot. Some do but
don't display to either monitor correctly.
<p>The trick is to find video adapters that were designed to be used
in conjunction with other video adapters. Many are not. The easiest
way for you to find out is check with Metro about what combinations of
video adapters they know work together. Chances are good the ones you
have don't. I know X Inside had a list of cards they knew work
together. You could search their web site (http://www.xinside.com or
http://www.xig.com) and see if that info is still there.
<p>Hope this helps.
<p>--
Michael J. Hammel
<P> <hr> <P>
<!--================================================================-->
<a name="colordp"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Color Depths with X
</H3>
<P>
Date: Wed Apr 2 13:27:40 1997<br>
From: Michael J. Hammel <a href="mailto:mjhammel@emass.com">mjhammel@emass.com</a><BR>
After fiddling with the xf86config file in a concerted effort to coax X
into displaying 16 bit color, I was dismayed to learn that with my
current hardware (16 megs RAM and a Cirrus Logic GL-5426) 16 bit color
is *impossible*...not because of any hardware in-capability, but because
of a certain limitation of X Windows itself...a problem with linear
addressing. Seems that to have 16 bit color under X, one must have
linear addressing enabled, which only works if the system has *no more
than 14 megs RAM*.
<p>Horse hockeys. 16 bit color is a limitation of the video subsystem and
has nothing to do with the memory of your system. Linear addressing in
the XFree86 X servers might be tied to system memory amounts, but that
would be a limitation in the XFree86 server, not in X. X defines
"method without policy", so such limitations just aren't built into X.
<p>A couple of things you should note: The number of colors available
under 16bit displays is actually *less* than the number available to
8bit displays. Why this is true has to do with the way 16bit display
hardware works. The actual color palette for 8 bit displays can have
millions of colors - it can only display 256 colors at a time, however.
Frugal use of colormaps can allow you to have nearly exactly the right
colors for any given application. 16 bit displays only have a palette
of 65k (roughly) colors. Once those are used up, you're outta luck.
<p>I'm not completely clear on what makes this difference such a problem
but if you visit the Gimp User's mailing list (see the Linux Graphics
mini-howto: http://www.csn.net/~mjhammel/linux/lgh.html) and ask this
question you'll get similar replies. Its been discussed quite at length
on the developers list, and most of them read the User's list.
<p>BTW, if you want to see if Linear Addressing is the real problem, try
the X Inside AcceleratedX demo server and see if it works in 16 bit
color for you. Generally, your video card needs at least 1M of on board
RAM (not system memory - this is video memory on the video card) to
run in 16Bit mode, but then you'll probably only be able to run in
640x480 or (at most) 800x600 resolution. To run at higher resolutions
you'll need more video memory.
<p>Hope this helps.
<p>--
Michael J. Hammel
<P> <hr> <P>
<!--================================================================-->
<a name="boot"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
Figuring Out the Boot Process</BR>
</H3><P>
Date: Fri, 04 Apr 1997 13:20:40 -0600<br>
From: David Ishee <a href=mailto:dmi1@Ra.MsState.Edu">dmi1@ra.MsState.Edu</a><BR>
One of the things that is confusing about Linux at first is which files
Linux uses to load programs and get the system started at bootup. Once
you figure out which programs are run during the boot process, which
order are they run? Here is an easy solution.
<p>On my Red Hat 4.0 system, the /etc/rc.d directory tree is where
everything happens. There are a lot of shell scripts in this set of
directories that are run when the system boots. To give yourself a
little more info, add some echo statements to the files. For example:
<pre>
edit /etc/rc.d/rc.sysinit and add the following lines at the beginning
echo " "
echo "**** Running /etc/rc.d/rc.sysinit ****
echo " "
</pre>
<p>Now when the system is booting you can see exactly when rc.sysinit is
run, and what programs it launches. Repeat the above process for all the
scripts you find.
<p>Now if the system hangs or gives an error during bootup you have a
better idea of where to look. If you don't have any problems while
booting then at least you have more info about what Linux is doing.
<p>
David
<P> <hr> <P>
<!--================================================================-->
<a name="ftp"></a>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
ftping Home</BR>
</H3><P>
Date: Thu, 3 Apr 1997 20:38:02 +0300 (EET DST)<br>
From: Kaj J. Niemi, <a href="mailto:kajtzu@4u.net">kajtzu@4u.net</a><br>
I read your article about ftping home with dynamic IPs.. Here's
something you might need if you get tired of looking at the screen every
time you want to find out the IP.
<pre>
ADDRESS=`/sbin/ifconfig | awk 'BEGIN { pppok = 0}
/ppp.*/ { pppok = 1; next }
{if (pppok == 1 ) {pppok = 0; print} }'\
| awk -F: '{print $2 }'| awk '{print $1 }'`
</pre>
<p>Just replace the ppp.* with whatever you want (if you have multiple
ppps running). The easiest thing would to be write a script called ftphome
(or similar) and make it first assign the address and then doing ftp or
ncftp $ADDRESS. The snippet is originally from a local firewall, at the part
where it needs to know what its' own address is. :-)
A friend of mine at <a href=mailto:mstr@ntc.nokia.com">
mstr@ntc.nokia.com</a> wrote this for me.
<p>
--
Kaj J. Niemi
<P> <hr> <P>
<!--================================================================-->
<center>Published in Linux Gazette Issue 17, May 1997</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_mail17.html"><IMG SRC="../gx/back2.gif" ALT=" Back "></A>
<A HREF="./lg_bytes17.html"><IMG SRC="../gx/fwd.gif" ALT=" Next "></A>
<P> <hr> <P>
<h5>This page maintained by the Assistant Editor of <I>Linux Gazette</I>,
<A HREF="mailto: gazette@ssc.com">gazette@ssc.com</A><BR>
Copyright &copy; 1997 Specialized Systems Consultants, Inc. </H5>
<P>
<H4>&quot;Linux Gazette...<I>making Linux just a little more fun!</I>&quot;</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_bytes17.html#general">News in General</a>
<li><a HREF="./lg_bytes17.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>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
GLUE Announcement
</H3>
<p>
<h4>Every GLUE User Group To Receive Free Copy of BRU 2000 Backup And Restore
Utility</h4>
<P>
<i>Linux Expo, Research Triangle Park, NC (April 4, 1997)</i> -
Enhanced Software Technologies, Inc. announced today that Groups of Linux
Users Everywhere (GLUE) will provide a free copy of the new BRU 2000 backup
and restore utility to GLUE user groups.
<P>
Enhanced Software Technologies, Inc. has joined Linux International as a
corporate member and is also offering members of GLUE user groups a
10-percent discount on purchases of BRU 2000.
<P>
<A HREF="http://www.estinc.com/">
Enhanced Software Technologies, Inc.</A>, a privately held corporation based in
Tempe, Arizona, is a leading provider of high-reliability systems
<p>Additional information on <a href="./bru.html">BRU Giveaway</a>.
<p>
GLUE is a project of SSC
publishers of <i>Linux Journal</i>. GLUE was implemented
to provide a world-wide member group for Linux User Groups. GLUE member
groups receive a subscription, materials for promoting and developing
their group, a way of advertising their group in a global setting, list-serv
and Linux Group location services, and discounts and samples from SSC and
<i>Linux Journal</i>. Other vendors may also offer special services or
discounts to GLUE member groups.
<p>Additional information on <a href="http://www.ssc.com/glue/index.html">Glue</a>.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
SOLID desktop for Linux offered free of charge to developers
</H3>
<P>
Solid Information Technology Ltd today announced a campaign
targeted at the community of Linux developers. Between March
and September 1997 Linux enthusiasts will be presented with
a free personal version of the robust SQL database engine
SOLID Server.
<P>
SOLID Server is a unique product by Solid Information Technology
Ltd, a privately held innovator of database
technologies.
<P>
To download your own copy of SOLID Desktop for Linux, access
<A HREF="http://www.solidtech.com/linuxfre.htm">http://www.solidtech.com/linuxfre.htm</A> to find a site near you.
<P>
<A HREF="./solid.html">Additional Information:</A><BR>
Solid Information Technology Ltd, <A HREF="http://www.solidtech.com.">http://www.solidtech.com.</A>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
The Elsop Webmaster Resource Center
</H3>
<P>
The Elsop Webmaster Resource Center<br>
<a href="http://www.elsop.com/wrc/">http:www.elsop.com/wrc/</a><br>
<p>Contains links and comprehensive
coverage of computer industry trade publications,
website development, HTML, servers, validators,
link checkers, and software for webmasters.
<p>Major sections include:
<ul>
<li>Computer Industry Publications
<li>Electronic Commerce Solutions
<li>High Technology Trade Shows & Conferences
<li>History of the Technology
<li>Internet, Cyberspace and Computer Law
<li>Internet Trade Associations and Societies
<li>Link Validators & Site Mappers
<li>Reference Room of Outstanding Resources for Webmasters
<li>Systems and Software Sources on the Web
<li>Website Development Services
</ul>
<p>Produced and Sponsored by the
Electronic Software Publishing Corporation
<a href="http://www.elsop.com/linkscan">http://www.elsop.com/linkscan</a>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Linux Jokes Wanted
</H3>
<p>
Do you consider yourself witty? Do you want to show your fabulous sense of
humor to the world? NOW IS YOUR CHANCE!
<P>
For several years now <I>Linux Journal</I> has been considering adding a monthly cartoon to
our magazine. We know who we could have "draw" the cartoons, but we really
don't have any idea what the jokes should be.
<P>
Please contribute any ideas you have for "Linux related" cartoons. The type
of cartoon we are imagining are one panel cartoons akin to what they have in
magazines like the New Yorker.
<P>
So <A HREF="mailto:linux@ssc.com">send</A> us your
favorite Linux jokes (one liners are best), and we will turn them into
cartoons.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Too Good Not To Print
</H3>
<P>
For a good time, check out this website!
<a
href="http://www.lightlink.com/fors/press/net-history.txt">http://www.lightlink.com/fors/press/net-history.txt</a>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
New User's Group in Knoxville
</H3>
<P>
There is a new user's group for Linux in Knoxvill, TN
They are called the Knoxville's Linux Users Base. Check out the web page
at
<a href="http://klub.ml.org">http://klub.ml.org</a>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
AfterStep Themes Page
</H3>
<P>
Take a look at the AfterStep Themes
page! Trae Mc Combs has been devoting some time to creating themes for
<a href="http://www.mindspring.com/~xwindow/as.html">http://www.mindspring.com/~xwindow/as.html</a><br>
or
<a href="http://www.mindspring.com/~xwindow/">http://www.mindspring.com/~xwindow</a>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Version 7 of Corel's WordPerfect for Linux
</H3>
<P>
<p>Software Development Corporation <a href="http://www.sdcorp.com">http://www.sdcorp.com</a> is working on
releasing version 7 of Corel's WordPerfect for Linux. It's expected to
ship sometime in April, with beta testing currently taking place.
<p>Their webpages seem to warn that only beta testers have access to the
software, but following the links takes you to the download area where
they're freely available.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Computer Comparison
</H3>
<P>
Here is a URL that has some interesting data:
<a href="http://fampm201.tu-graz.ac.at/karl/timings30.html">http://fampm201.tu-graz.ac.at/karl/timings30.html</a><br>
This web site is maintained by Karl Unterkofler, and has comparisons of
various computers running the latest versions of Mathemetica. Karl and
others run a series of tests on the machines, that involve timing
mathematical problems.
<p>8 of the 10 fastest machines are running the Mac OS! the first windows
machine doesn't make a showing until 11th place( a pentium pro 200Mhz
running Windows NT 4.0) Incidently this ppro 200 is beat by a Mac 7500
150 Mhz!
<p>You might wonder how this can be when the SPECint95 for Pentium Pros and
for Power PC 604's are so close? Its the operating system dummy!
<p>What do I mean?
<p>The Intel machines and the Macs are pretty equal, its Windows that slows
things down. If you check out the URL you'll see that although 8 of the
top ten are Macs or Mac clones, 2 of them are Intel pentium Pro 200Mhz
machines. Sadly for the Mac, the number one spot is a Pentium Pro 200
with 64 Meg RAM and a 256kb L2 cache running LINUX 2.0.27.
<p>This barely beats the number 2 machine, a 225Mhz Power Tower Pro from
Power Computing with 256 Meg RAM and a 1Meg L2 cache.
The other Intel in the top 10 is a Pentium Pro 200Mhz with 128Meg Ram and
256Kb L2 cache, running NeXT STEP 3.3.
<p>I don't think that Mac owners should be ashamed of losing to a LINUX
machine. LINUX is the result of an amazing effort put forth by many
dedicated programmers to produce a state of the art 32bit operating
system that utilizes hardware to the fullest. Mac users should be happy
that they can go head to head with such an OS, and still maintain the
great human interface of the Mac!
<p>The only other contender is a NeXT machine! Wait'll your windows friends
see redbox!
Oh, BTW the first Win '95 machine doesn't make a showing until 15th
place. its a Pentium pro 200, 64 MB, 256kb, OS: Win95 and is just below a
PowerMac 7600/120, 48MB, 256kb, MacOS!
<p>So if a windows user tells you their machine is faster, tell them that
you know...if they switch to LINUX.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Word Processor for the Linux Environment
</H3>
<P>
The development of 'wp', a word processor for the Linux environment has
recently been started. Although it's primary goal is a Linux-based word
processor, wp will eventually be available for many other platforms.
<p>WP is an open system, object orientated, and object driven; written mainly
using C++, although little code has of yet been written. The current
objective is a full design specification/mission statement and determining
the current products that can be used to help the development of the
product further.
<p>Because of this openness, it is proposed to have the user interface
seperate from the main program; the reason for this meaning that the user
can choose whichever interface suits them best, from a ncurses driven text
interface to an X-Windows display using different widget sets.
<p>The web site for Wp is at <a href="http://sunsite.unc.edu/paulc/wp">http://sunsite.unc.edu/paulc/wp</a>
<p>If you wish to obtain the design specification notes for wp, they are also
available at the above site.
<p>A FAQ is currently being prepared, if you have any questions or
suggestions, please send them to <a href="mailto:wp@squiznet.demon.co.uk">wp@squiznet.demon.co.uk</a>
<p>If you wish to contribute to the project in any form, please contact
<a href="mailto:paulc@sunsite.unc.edu">paulc@sunsite.unc.edu</a> and introduce yourself, a copy of which will be sent
to the wp-developers mailing list unless you specifically state that you
do not wish for this to happen.
<a name="software"></a>
<P> <hr> <P>
<!-- =================================================================== -->
<center><H3> Software Announcements </H3></center>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Xcoral 3.0
</H3>
<P>
Xcoral-3.0 has been released and now available on the Net.
<ul>
<li> EUROPE: <a href="ftp://ftp.inria.fr">X/contrib-R5/clients</a>
<li> USA: <a href="ftp://ftp.x.org">contrib/editors</a>
</ul>
<p>Xcoral is a multiwindow mouse-based text editor for
the X Window System. It contains a built-in browser that enables you to
navigate through C functions, C++ classes, Java classes, methods and files.
It also contains a SMall Ansi C Interpreter (Smac) which is also built-in
to extend the editor's possibilities
(user functions, key bindings, modes etc).
Xcoral provides variable width fonts, menus, toolbar,
scrollbars, buttons, search, regions, kill-buffers, macros and
undo. An on-line manual box, with a table of contents
and an index, helps you to use and customize the editor.
Xcoral also offers facilities to write Latex documents
and Html pages.
Xcoral is a direct Xlib client and runs on color/bw
X Display.
<p>OS: SunOS 4.1.x, Solaris 2.[45], LINUX, AIX, HPUX,
IRIX and OSF-1.
<p>Changes from xcoral-2.5:
<ul>
<li> New browser for C/C++ and Java.
<li> Standard X selection mecanism.
<li> Toolbar
<li> Some bugs fixed...
</ul>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Beta Version of EM86
</H3>
<P>
The Linux/Alpha team at Digital Equipment Corporation
today is releasing a developers' beta version of EM86, a Linux/x86
emulator for Linux/Alpha. Using components of the
DIGITAL FX!32 technology, EM86 is a software emulator that enables
Linux/Alpha systems to run Linux/x86 software without modification.
<p>EM86 currently supports statically linked and dynamically linked x86
ELF32 binaries under Linux/Alpha. Future enhancements will include
support for iBCS-2 compliant executables, improved emulator performance,
and interoperation with native Alpha code. A release incorporating
these features is anticipated in July, 1997.
<p>They are releasing a beta version of EM86 at this time to provide
Linux developers early access to the software, to aid in the
verification of software packages, and to provide feedback and bug
reports to the Linux/Alpha team.
<p>The following Linux/x86 software packages run successfully on this
beta version of EM86, with some qualifications as described in the
README file included in the distribution:
<ul>
<li> Netscape Navigator Gold 3.01
<li> Adobe Acrobat Reader 3.0
<li> Red Baron web browser 3.00
<li> Applixware 4.2
</ul>
<p> EM86 may be obtained via anonymous ftp from:
<a href="ftp://ftp.digital.com/pub/DEC/Linux-Alpha/em86">ftp://ftp.digital.com/pub/DEC/Linux-Alpha/em86</a>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
XForms V0.86
</H3>
<P>
XForms V0.86 is now available from:
<ul>
<li><a href="http://bragg.phys.uwm.edu/xforms">http://brigg.phys.uwm.edu/xforms</a>
<li><a href="ftp://einstein.phys.uwm.edu/pub/xforms">ftp://einstein.phys.uwm.edu/pub/xforms</a>
</ul>
for Linux/i386, Linux/alpha, Linux/sparc, and Linux/m68k.
<p>XForms is a graphical user interface toolkit and builder based on Xlib
for X Window Systems. XForms is a portable and efficient C library
that can be used in both C and C++ programs.
The library works in all visuals and all depths (1-24) and comes
with a rich set of objects such as buttons (of many flavors, including color
XPMs as labels) , browsers, sliders, and menus integrated into an
elegant event/object callback execution model that allows fast and
easy construction of X-applications. It also has OpenGL (on SGI) and
Mesa support.
<p>XForms comes bundled with
<ul>
<li>Precompiled library (static and shared) and header files.
<li>Source code for 50+ demonstration programs;
<li>Precompiled fdesign, an interactive GUI builder that can
be used to design dialogues in a WYSIWYG way and to output the
corresponding UI code for you.
<li>250+ pages of indexed documentation (tutorial and reference) in both
PostScript and html
</ul>
<p>perl, ada95, python and fortran bindings to xforms are in alpha/beta.
Please visit the xforms' home page for more info.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Debian 1.3 Available for Beta Test
</H3>
<P>
Debian 1.3 is now in beta test. We are performing a month-long test
with an organized quality control team. If you'd like to be an official
beta tester, please contact Dale Scheetz <a href="mailto:dwarf@polaris.net">dwarf@polaris.net</a> .
<p>The Debian 1.3 files are under the "frozen" directory on most of the
Debian mirror sites. There are now 73 Debian mirrors worldwide! You can
find the mirror list at
<a href="ftp://ftp.debian.org/debian/README.mirrors">ftp://ftp.debian.org/debian/README.mirrors</a> or
<a href="ftp://debian.crosslink.net/pub/debian/README.mirrors">ftp://debian.crosslink.net/pub/debian/README.mirrors</a>. Please consider
that this is beta-quality software and there will be bugs. If you have
any problem, please see the information on our bug-tracking system
at <a href="http://www.debian.org/support.html">http://www.debian.org/support.html</a>, or write to Dale at the above
address.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
Freedom Desktop Lite Announced (1.01)
</H3>
<P>
Announcing the public availability of the Freedom
Desktop Lite. Freedom Desktop Lite is a
desktop environment/GUI integrated to the Unix
environment. It
helps users interact with Unix quickly and efficiently. Freedom
Desktop runs transparently in a variety of Unix environments,
from Desktop computers (i.e. Linux) to enterprise workstations.
<p>The Freedom Desktop Lite environment bundles the following
applications:
<ul>
<li>File Manager
<li>Program Manager
<li>Print Tool
<li>Find Tool
<li>Editor
<li>Terminal emulator
<li>Pixmap/Icon Editor
<li>Screen grabber
<li>Screen saver
<li>Rolodex
</ul>
For more information and the ftp site feel free to visit <a href="http://freedom.lm.com/desktop.html">http://freedom.lm.com/desktop.html</a>
<P> <hr> <P>
<!--================================================================-->
<center>Published in Linux Gazette Issue 17, May 1997</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_tips17.html"><IMG SRC="../gx/back2.gif" ALT=" Back "></A>
<A HREF="./answer.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; 1997 Specialized Systems Consultants, Inc. </H5>
<P>
<H4>&quot;Linux Gazette...<I>making Linux just a little more fun!</I>&quot;
</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:jimd@starshine.org">jimd@starshine.org</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="./answer.html#fs">fs's</a>
<li><a HREF="./answer.html#unix">Linux/Unix Emulator</a>
<li><a HREF="./answer.html#vidX">Using X With 2 Monitors and 2 Video
Cards</a>
<li><a HREF="./answer.html#host">Virtual Hosting</a>
<li><a HREF="./answer.html#response">Response from Weitse Venema</a>
<li><a HREF="./answer.html#file">Automatic File Transfer</a>
<li><a HREF="./answer.html#ftpd">Installing wu-ftpd on a Linux Box</a>
<li><a HREF="./answer.html#boot">Trying to Boot a Laptop</a>
<li><a HREF="./answer.html#zmode">zmodem Reply</a>
<li><a HREF="./answer.html#start">StartX</a>
<li><a HREF="./answer.html#imap">IMAP and Linux</a>
<li><a HREF="./answer.html#imap2">IMAP Again</a>
<li><a HREF="./answer.html#uucp">UUCP Questions</a>
<li><a HREF="./answer.html#flops">Using MS-DOS Floppies</a>
<li><a HREF="./answer.html#inetd">inetd Questions</a>
<li><a HREF="./answer.html#modem">Navas Modem FAQ</a>
<li><a HREF="./answer.html#modem2">Setting Up a Modem</a>
<li><a HREF="./answer.html#userid">User Identification</a>
<li><a HREF="./answer.html#duplic">Duplicating a Linux Installed HD</a>
</ul>
<p><hr><p>
<!--================================================================-->
<a name="fs"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
fs's
</h3>
<P><B>
From: Aaron M. Lee <a
href="mailto:aaron@shifty.adosea.com">aaron@shifty.adosea.com</a><br>
<p>Howdy Jim,
My name's Aaron and I am sysadmin Cybercom Corp., an ISP in
College Station, TX. We run nothing but Linux, and have been involved w/
a lot of hacking and development on a number of projects. I have an
unusual problem and have exhausted my resources for finding an answer- so
I thought you might be able to help me out, if you've got the time.
Anyway, here goes...
<p>I've got a scsi disk I was running under Sparclinux that has 3
partitions, 1 Sun wholedisk label, 2 ext2. That machine had a heart
attack, and we don't have any spare Hypersparcs around- but I _really_
need to be able to mount that drive to get some stuff off of it. I compiled
in UFS fs support w/ Sun disklabel support into the kernel of an i386 Linux
box, but the when I try to mount it, it complains that /dev/sd** isn't a
valid block device, w/ either the '-t ufs' or '-t ext2' options. Also,
fdisk thinks the fs is toast, and complains that the blocks don't end
in physical boundaries (which is probably the case for an fdisk that
doesn't know about Sun disklabels), and can't even tell that the
partitions are ext2 (it thinks one of them is AIX!). Any ideas?
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
Consider the nascent state of Sparc support for Linux
I'm not terribly surprised that you're having problems.
You seem to be asking:
"How do I get Linux/Intel to see the fs on
this disk?"
<p> However I'm going to step back from the that question
and ask the broader question:
"How do you recover the (important) data off of
that disk in a usable form?"
<p> Then I'll step back even further and ask:
"How important is that data? (what is its
recovery worth to you)?"
<p> ... and<br>
"What were the disaster plans, and why
are those plans inadequate for this
situation?"
<p> If you are like most ISP's out there -- you have not
disaster or recovery plans, and little or no backup
strategy. Your boss essentially asks you to running
back and forth on the high wire at top speed -- without
a net.
<p> As a professional sysadmin you must resist the pressure
to perform in this manner -- or at least you owe it to
yourself to carefully spell out the risks.
<p> In this case you had a piece of equipment that was
unique the Sparc system -- so that any failure of
any of its components would result in the lack of
access to all data on that system.
<p> Your question makes it clear that you didn't have
sufficiently recent backups of the data on that
system (otherwise the obvious solution would be
to restore the data to some other system and
reformat the drive in question).
<p> My advice would be to rent (or even borrow) a
SPARC system for a couple of days (a week is a
common minimum rental period) -- and install
the disk into that.
<p> Before going to the expense of renting a system
(or buying a used one) you might want to ensure
that the drive is readable at the lowest physical
level. Try the dd command on that device. Something
like:
<pre> dd if=/dev/sda | od | less
</pre>
<p> ... should let you know if the hardware is operational.
If that doesn't work -- double and triple-check all of the
cabling, SCSI ID settings, termination and other hardware
compatibility issues. (You may be having some weird problem
with a SCSI II differential drive connecting to an
incompatible controller -- if this is an Adaptec 1542B
-- be sure to break it in half before throwing it away
to save someone else the temptation (the 1542C series is
fine but the B series is *BAD*)).
<p> Once you are reasonably confident that the hardware
is talking to your system I'd suggest doing a direct,
bitwise, dump of the disk to a tape drive. Just use a
command like:
<pre> dd if=/dev/sda of=/dev/st0
</pre>
<p> ... if you don't have a sufficiently large tape drive
(or at least a sufficiently large spare hard disk) *and
can't get one* than consider looking for a better
employer.
<p> Once you have a tape backup you can always get back
to where you are now. This might not seem so great
(since you're clearly not where you'd like to be) but
it might be infinitely preferable to where you'll be
if you have a catastrophic failure on mounting/fsck'ing
that disk.
<p> For the broader problem (the organizational ones rather
than the technical ones) -- you need to review
the requirements and expectations of your employer --
and match those against the resources that are being
provided.
<p> If they require/expect reliable access to their data --
they must provide resources towards that end. The most
often overlooked resource (in this case) is sysadmin
time and training. You need the time to develop
disaster/recovery plans -- and the resources to test
them. (You'd be truly horrified at the number of sites
that religiously "do backups" but have an entire staff that
has never restored a single file from those).
<p> Many organizations can't (or won't) afford a full spare
system -- particularly of their expensive Sparc stations.
They consider any system that's sitting on a shelf to be a
"waste." -- This is a perfectly valid point of view.
However -- if the production servers and systems are
contributing anything to the companies bottom line --
there should be a calculable cost for down time. If that's
the case then there is a basis for comparison to the costs of
rentals, and the costs of "spare" systems.
<p> Organizations that have been informed of this risks and
costs (by there IS staff) and continue to be unwilling or
unable to provide the necessary resources will probably
fail.
<P><B><img align=bottom alt=" " src="../gx/ques.gif">
Thanks in advance for any possible help,
--Aaron
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
It's often the case that I respond with things that
I suspect my customer don't want to hear.
The loss of this data (or the time lost to recovering
it) is an opportunity to learn and plan -- you may
prevent the loss of much more important information
down the road if you now start planning for the
inevitable hardware and system failures.
<p><hr><p>
<!--================================================================-->
<a name="unix"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Linux/Unix Emulator
</h3>
<P><B>
From:Steven W., <a href="mailto:steven@gator.net">steven@gator.net</a><br>
<p> Can you help me? Do you know of a Unix (preferably Linux) emulator
that runs under Windows95?
<p> -- Steven.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
Short Answer:
I don't know of one.
<p> Longer Answer:
<p> This is a tough question because it really doesn't
*mean* anything. An emulator is a piece of software
that provide equivalent functionality to other software
or hardware. Hopefully this software is indistinguishable
from the "real" thing in all ways that count.
<p> (Usually this isn't the case -- most VT100
terminal emulation packages have bugs in them
-- and that is one of the least complicated
and most widespread cases of emulation in the
world).
<p> A Unix "emulator" that ran under Win '95 would probably not be
of much use. However I have to ask what set of features
you want emulated?
<p> Do you want a Unix-like command shell (like
Korn or Bash)? This would give you some of the
"feel" of Unix.
<p> Do you want a program that emulates one of the
GUI's that's common on Unix? There are X Windows
"display servers" (sort of like "emulators") that
run under NT and '95. Quarterdeck's eXpertise
would be the first I would try.
<p> Do you want a program that allows you to run
some Unix programs under Win '95? There are
DOS, OS/2, and Windows (16 and 32 bit) ports of
many popular Unix programs -- including most of
the GNU utilities. Thus bash, perl, awk, sed,
vi, emacs, tar, and hundreds of other utilities
can be had -- most of them for free.
<p> Do you want to run pre-compiled Unix binaries
under Win '95? This would be a very odd request
since there are dozens of implementations of
Unix for the PC platform and hundreds for other
architectures (ranging from Unicos on Cray super-
computers to Minix and Coherent on XT's and 286's).
Binary compatibility has playing only a tiny role
in the overall Unix picture. I suspect that
supporting iBCS (a standard for Unix binaries on
intel processors -- PC's) under Win '95 would be a
major technical challenge (and probably never
provide truly satisfying results).
<p> *note*: One of the papers presented at Usenix in
Anaheim a couple of months ago discussed the
feasibility of implementing an improved Unix
subsystem under NT -- whose claim of POSIX support
as proven to be almost completely useless in the
real world. Please feel free to get a copy of
the Usenix proceeding if you want the gory details
on that. It might be construed as a "Unix emulation"
for Windows NT -- and it might even be applicable to
Win '95 -- with enough work.
<p> If you're willing to run your Windows programs
under Unix there's hope. WABI currently supports
a variety of 16-bit Windows programs under Linux
(and a different version support them under Solaris).
Also work is continuing on the WINE project -- and
some people have reported some success in running
Windows 3.1 in "standard mode" under dosemu (the
Linux PC BIOS emulator). The next version of WABI
is expect to support (at least some) 32-bit Windows
programs.
<p> My suggestion -- if this is of any real importance to you --
is that you either boot between Unix and DOS/Windows or that
you configure a separate machine as a Unix host -- put it in
a corner -- and using your Win '95 system as a terminal,
telnet/k95 client and/or an X Windows "terminal" (display
server).
<p> By running any combination of these programs on your Windows
box and connecting to your Linux/Unix system you won't have
to settle for "emulation." You'll have the real thing --
from both sides. In fact one Linux system can serve as the
"Unix emulation adapter" for about as many DOS and Windows
systems as you care to connect to it.
<p> (I have one system at a client site that has about 32Mb
of RAM and 3Gb -- it's shared by about 300 shell and
POP mail users. Granted only about 20 or 30 of them are
ever shelled at any given time but it's no where near it's
capacity).
<p> I hope this gives you some idea why your question is
a little non-sensical. Operating systems can be viewed
from three sides -- user interface (UI), applications
programming interface (API), and supported hardware
(architecture).
<p> Emulating one OS under another might refer to emulating
the UI, or the API or both. Usually emulation of the
hardware support is not feasible (i.e. we can't run DOS
device drivers to provide Linux hardware support).
<p> If one implemented the full set of Unix system calls
in a Win '95 program that provided a set of "drivers"
to translate a set of Unix like hardware abstractions
into calls to the Windows device drivers -- and one
ported a reasonable selection of software to run under
this "WinUnix kernel" -- one could call that "Unix emulation."
<p> However it would be more accurate to say that you had
implemented a new version of Unix on a virtual machine
which you hosted under Windows.
<p> Oddly enough this is quite similar to what the Lucent
(Formerly Bell Labs?) Inferno package does. Inferno
seems to have evolved out of the Plan 9 research project
-- which apparently was Dennis Ritchie's pet project for
a number of years. I really don't know enough about
the background of this package -- but I have a CD
(distributed to attendees of the aforementioned Usenix
conference) which has demo copies of Inferno for several
"virtual machine" platforms (including Windows and Linux).
<p> Inferno is also available as a "native" OS for a couple
of platforms (where it includes it's own device drivers
and is compiled as direct machine code for a machine's
platform).
<p> One reason I mention Inferno is that I've heard that
it offers features and semantics that are very similar
to those that are common in Unix. I've heard it described
as a logical outgrowth of Unix that eschews some of the
accumulation of idiosyncrasies that has plagued Unix.
<p> One of these days I'll have to learn more about that.
<P><B>
<img align=bottom alt=" " src="../gx/ques.gif">
I have Windows95 and Linux on my system, on separate partitions, I
can't afford special equipment for having them on separate machines.
I really like Linux, and Xwindows, mostly because of their great
security features. (I could let anybody use my computer without
worrying about them getting into my personal files). Windows95's
pseudo-multi-user system sucks really bad. So, mainly, this is why I
like Linux. I also like the way it looks. Anyways, I would just run
Linux but my problem is that Xwindows doesn't have advanced support
for my video card, so the best I can get is 640x480x16colors and I
just can't deal with that. Maybe I'm spoiled. The guy I wrote on
the Xwin development team told me that they were working on better
support for my card, though. (Aliance Pro-Motion). But, meanwhile,
I can't deal with that LOW resolution. The big top-it-off problem is
that I don't know of anyway to have Linux running _while_ Win95 is
running, if there even is a way. If there was, it would be great,
but as it is I have to constantly reboot and I don't' like it. So
this is how I came to the point of asking for an emulator. Maybe
that's not what I need after all. So what can I do? Or does the
means for what I want not exist yet?
<p>-- Steven.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
If you prefer the existing Linux/X applications and
user interface -- and the crux of the problem is support
for your video hardware -- focus on that. It's a simpler
problem -- and probably offers a simpler solution.
<p> There are basically three ways to deal with a lack of
XFree86 support for your video card:
<ul>
<li> Help write an XFree86 driver
(I'm not a coder either -- but I do occasionally
beat the bushes and offer bribes to coder
friends)
<li> Look for Metro-X or other (probably commercial)
support. (A copy of Metro-X comes with Red Hat
4.1 for about $50 -- so this is not outrageously
expensive).
<li> Replace the video card. There are plenty of
really good video cards that are supported by
XFree86. Number 9, and Matrox have good track
records. Some of the 2Mb PCI cards are only
about $100 (US).
</ul>
<p> Be sure to contact the manufacturer to ask for a
driver. Point out that they may be able to make
small changes to an existing XFree86 driver. You
can even offer to help them find a volunteer
(where you post to the comp.os.linux.dev...sys.
newsgroup and one or two of the developer's mailing
lists -- and offer some support). Just offering to
do some of the "legwork" maybe be a significant
contribution.
<p> This is an opportunity to be a "Linux-Activist."
<p>--
Jim
<p><hr><p>
<!--================================================================-->
<a name="vidX"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Using X with 2 Monitors and 2 Video Cards
</h3>
<P><B>
From:Charles A. Barrasso<a
href="mailto:charles@blitz.com">charles@blitz.com</a><br>
I was wondering how I would go about using X with 2 monitors and 2
video cards? I am currently using XFree86 window manager. I know you
can do this with the MetroX window manager but that costs money :(.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
I'm sure I gave a lengthy answer to this fairly recently.
Maybe it will appear in this month's issue (or maybe
I answered it on a newsgroup somewhere).
<p> In any event, the short answer is: You don't.
<p> The PC architecture doesn't support using multiple
VGA/EGA cards concurrently. I don't think XFree86 can
work with CGA cards (and who'd want to!). You might
be able to get a Hercules compatible Monochrome Graphics
Adapter (MGA) to work concurrently with a VGA card (since
they don't use overlapping address spaces). I don't know
if this is the method that Metro-X supports.
<p> There are specialized video adapters (typically very expensive
-- formerly in the $3000+ range) that can co-exist with
VGA cards. Two sets of initials that I vaguely recall are
TIGA and DGIS. Considering that you seem unwilling to
pay $100 (tops) for a copy of Metro-X I think these --
even if you can still find any of them -- are way out of
your price league.
<p> Another, reasonable, alternative is to connect a whole
Xterminal or another whole system and run X on that. You
can then remotely display your windows on that about as
easily as you could set them to display on the local
server.
<p> (I know -- you might not get some cool window manager
to let you drag windows from one display server to another
-- a trick which I've seen done with Macs under MacOS and
with Suns and SGI's. But I've never set one of those up
anyway -- so I couldn't begin to help you there).
<p> You might double check with the Metro-X people to see
what specific hardware is required/supported by their
multiple display feature and then check with the XFree86.org
to see if anyone has any drivers for one of those supported
configurations.
<p> As a snide note I find your phrase "that costs money :("
to be mildly offensive. First the cost of an additional
monitor has got to be at least 3 times the price of
a copy of Metro-X. Second "free" software is not about
"not having to pay money."
<p> I'm not trying to sell you a copy of Metro-X here. I
don't use it -- and I specifically choose videos cards
that are supported by XFree86 when I buy my equipments.
<p> Likewise I don't recommend Linux to my customers because
it "doesn't cost them anything." In fact it does cost
them the time it takes me to install, configure and maintain
it -- which goes for about $95/hr currently. I recommend
Linux because it is a better tool for many jobs -- and because
the benefits of it's being "free" -- in the GNU sense of the
term -- are an assurance that no one can "have them over a
barrel" for upgrades or additional "licensing" fees. They are
always *free* to deploy Linux on as many systems as they want,
have as many users and/or processes as they want on any system,
make their own modifications to the vast majority of tools
on the system or hire any consultants they want to make the
customizations they need.
<p> I'm sorry to be so "political" here -- but complaining
that Metro-X "costs money" and asking me for a way to
get around that just cost me about $50 worth of my time.
Heck -- I'll go double or nothing -- send my your postal
address and I'll buy you a copy of RedHat 4.1. That comes
with a license for one installation of Metro-X and only
costs about $50. I'll even cover the shipping and handling.
<p> (Please call them first to make sure that it really does
support your intended hardware configuration).
<P><B><img align=bottom alt=" " src="../gx/ques.gif">
Thanks for the time,
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
No problem. (I did say "mildly" didn't I).
<p>
--
Jim
<p><hr><p>
<!--================================================================-->
<a name="host"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Virtual Hosting
</h3>
<P><B>
From: Wietse Venema <a
href="mailto:wietse@wzv.win.tue.nl">wietse@szv.sin.tue.nl</a><br>
tcpd has supported virtual hosting for more than two years. Below
is a fragment from the hosts_access(5) manual page.
</B>
<p><B> Wietse
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
Thanks for the quick response. I'll have to play with
that. I suppose a custom "virtual finderd" would
be a good experiment.
<p> Do you know where there are any working examples of this
and the twist option posted to the 'net? I fight with
some of these and don't seem to get the right results.
<p> What I'd like is an example that drops someone into a
chroot'd jail as "nobody" or "guest" and running a
copy of lynx if they are from one address -- but
lets them log in a a normal user if they are from an
internal address. (We'll assume a good anti-spoofing
packet-filter on the router(s)).
<p> Did you ever add the chrootuid functionality to tcpd?
<p> How would you feel about an option to combine the
hosts.allow and hosts.deny into just tcpd.conf?
<p> (I know I can already put all the ALLOW and DENY
directives in a single file -- and I'm not much of a
programmer but even *I* could patch my own copy to
change the filename -- I'm just talking about the
general case).
<p> SERVER ENDPOINT PATTERNS<br>
In order to distinguish clients by the network address
that they connect to, use patterns of the form:
<pre>
process_name@host_pattern : client_list ...
</pre>
<p> (which is what he said one to me when I suggested merging
his chrootuid code with tcpd).
<p> I've blind copied Wietse on this (Hi!). I doubt he has
time to read the Linux Gazette.
--
Jim
<p><hr><p>
<!--================================================================-->
<a name="response"</a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Response from Weitse Venema
</h3>
<P><B>
From:Wietse Venema, <a href="mailto:wietse@wzv.win.tue.nl">wietse@wzv.win.tue.nl</a><br>
Do you know where there are any working examples of this
and the twist option posted to the 'net? I fight with
some of these and don't seem to get the right results.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
Use "twist" to run a service that depends on destination address:
fingerd@host1: ALL: twist /some/where/fingerd-for-host1
<P><B>
<img align=bottom alt=" " src="../gx/ques.gif">
What I'd like is an example that drops someone into a
chroot'd jail as "nobody" or "guest" and running a
copy of lynx if they are from one address -- but
lets them log in a a normal user if they are from an
internal address. (We'll assume a good anti-spoofing
packet-filter on the router(s)).
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
I have a little program called chrootuid that you could use.
<P><B>
<img align=bottom alt=" " src="../gx/ques.gif">
Did you ever add the chrootuid functionality to tcpd?
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
I would do that if there was a performance problem. Two small
programs really is more secure than a bigger one.
<P><B>
<img align=bottom alt=" " src="../gx/ques.gif">
How would you feel about an option to combine the
hosts.allow and hosts.deny into just tcpd.conf?
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
What about compatibility with 1 million installations world-wide?
<P><B>
<img align=bottom alt=" " src="../gx/ques.gif">
(I know I can already put all the ALLOW and DENY
directives in a single file -- and I'm not much of a
programmer but even *I* could patch my own copy to
change the filename -- I'm just talking about the
general case).
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
This is because the language evolved over time. Compatibility can
become a pain in the rear.
<p>--
Weitse
<p><hr><p>
<!--================================================================-->
<a name="file"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Automatic File Transfer
</h3>
<P><B>
From:Kenneth Ng, <a href="mailto:kenng@kpmg.com">kenng@kpmg.com</a><br>
In Linux Gazette, there is a mention of how to transfer files
automatically using ftp.
Here is how:
<pre>
#!/bin/csh
ftp -n remote.site << !
user joe blow
binary
put newfile
quit
!
</pre>
</B>
<p><B>And that's it. Granted ssh is better. But sometimes you have to go
somewhere that
only supports ftp.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
That's one of several ways. Another is to use ncftp
-- which supports things like a "redial" option to keep
trying a busy server until it gets through. ncftp also has
a more advanced macro facility than the standard .netrc (FTP).
<p> You can also use various Perl and Python libraries (or classes)
to open ftp sessions and control them. You could use 'expect'
to spawn and control the ftp program.
<p> All of these methods are more flexible and much more robust
than using the standard ftp client with redirection ("here"
document or otherwise).
<p>
--
Jim
<p><hr><p>
<!--================================================================-->
<a name="ftpd"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Installing wu-ftpd on a Linux Box
</h3>
<P><B>
From: Stephen P. Smith, <a href="mailto:ischis@evergreen.com">ischis@evergreen.com</a><br>
I just installed wu-ftpd on my linux box. I have version 2.4.
I can login under one of my accounts on the system and everything
works just fine.
</B>
<p><B>If I try an anonymous ftp session, the email password is rejected.
what are the possible sources of failure?
where should i be going for more help? :-)
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
Do you have a user named 'ftp' in the /etc/passwd file?
<P><B><img align=bottom alt=" " src="../gx/ques.gif">
done.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
wu-ftpd takes that as a hint to allow *anonymous* FTP.
If you do have one -- or need to create one -- be sure that
the password for it is "starred out." wu-ftpd will not
authenticate against the system password that's defined for a
a user named "ftp."
<P><B><img align=bottom alt=" " src="../gx/ques.gif">
done.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
You should also set the shell to something like /bin/false or
/bin/sync (make sure that /bin/false is really a binary and
*not* a shell script -- there are security problems -- involve
IFS (inter-field separators) if you use a shell script in the
/etc/passwd shell field).
<P><B><img align=bottom alt=" " src="../gx/ques.gif">
done.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
There is an FAQ for anonymous FTP (that's not Linux specific).
There is also a How-To for FTP -- that is more Linux oriented.
If you search Yahoo! on "wu-ftp" you'll find the web pages
at Washington University (where it was created) and at
academ.com -- a consulting service that's taken over development
of the current beta's.
<P>
<img align=bottom alt=" " src="../gx/ques.gif">
<B>Guess I will just have to do it the hard
way. Will tell you what I find (just in
case you want to know.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
What does your /etc/ftpaccess file look like?
<p> Did you compile a different path for the ftpaccess file
(like /usr/local/etc/)?
<p> What authentication libraries are you using (old
fashioned DES hashes in the /etc/passwd, shadow,
shadow with MD5 hashes -- like FreeBSD's default,
or the new PAM stuff)?
<p> Is this invoked through inetd.conf with tcpd
(the TCP Wrappers)? If so, what does your /var/log/messages
say after a login failure? (Hint: use the command:
'tail -f /var/log/messages > /dev/tty7 &' to leave a continuously
updated copy of the messages file sitting on one of your
-- normally unused -- virtual consoles).
<p>
One trick I've used to debug inetd launched programs (like
ftpd and telnetd) is to wedge a copy of strace into the
loop. Change the reference to wu.ftpd to trace.ftpd --
create a shell or perl script named trace.ftpd that consists
of something like:
<pre>
#! /bin/sh
exec strace -o /tmp/ftpd.strace /usr/sbin/wu.ftpd
</pre>
<p> ... and then inspect the strace file for clues about
what failed. (This is handy for finding out that the
program couldn't find a particular library or configuration
file -- or some weird permissions problems, etc).
<p>
--
Jim
<p><hr><p>
<!--================================================================-->
<a name="boot"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Trying to Boot a Laptop
</h3>
<P><B>
From: Yash Khemani, <a href="mailto:khemani@plexstar.com">khemani@plexstar.com</a><br>
I've got a Toshiba satellite pro 415cs notebook computer on which I've
installed RedHat 4.1. RedHat 4.1 was installed on a jaz disk connected
via an Adaptec slimscsi pcmcia adapter. the installation went
successfully, i believe, up until the lilo boot disk creation. i
specified that i wanted lilo on a floppy - so that nothing would be
written to the internal ide drive and also so that i could take the
installation and run it at another such laptop. after rebooting, i
tried booting from the lilo floppy that was created, but i get nothing
but continuous streams of 0 1 0 1 0 1...
</B>
<p><B>i am guessing that the lilo floppy does not have on it the pcmcia
drivers. what is the solution at this point to run RedHat on this
machine?
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
You've got the right idea.
The 1010101010101... from LILO is a dead giveaway that
your kernel is located on some device that cannot be
accessed via the BIOS.
<p> There are a couple of ways to solve the problem.
I'd suggest LOADLIN.EXE.
<p> LOADLIN.EXE is a DOS program (which you might have
guessed by the name) -- which can load a Linux kernel
(stored as a DOS file) and pass it parameters (like
LILO does). Basically LOADLIN loads a kernel (Linux or
FreeBSD -- possibly others) which then "kicks" DOS
"out from under it." In other words -- it's a one-way
trip. The only way back to DOS is to reboot (or
run dosemu ;-) .
<p> LOADLIN is VCPI compatible -- meaning that it can run
from a DOS command prompt even when you have a memory
manager (like QEMM) loaded. You can also set LOADLIN
as your "shell" in the CONFIG.SYS. That's particularly
handy if you're using any of the later versions of DOS
that support a multi-boot CONFIG.SYS (or you're using the
MBOOT.SYS driver that provided multi-boot features in
older versions of DOS).
<p> To use LOADLIN you may have to create a REALBIOS.INT
file (a map of the interrupt vectors that are set by
your hardware -- before any drivers are loaded).
To do this you use a program (REALBIOS.EXE) to create
a special boot floppy, then you boot off that floppy
(which records the interrupt vector table in a file)
-- reboot back off your DOS system and run the second
stage of the REALBIOS.EXE.
<p> This little song and dance may be necessary for each
hardware configuration. (However you can save and
copy each of the REALBIOS.INT files if you have a
couple of configurations that you switch between --
say, with a docking station and without).
<p> With LOADLIN you could create a DOS bootable floppy,
with a copy of LOADLIN.EXE and a kernel (and the
REALBIOS.INT -- if it exists). All of that will
just barely fit on a 1.44M floppy.
<p> Another way to do this would be to create a
normal DOS directory on your laptop's IDE drive --
let's call it C:\LINUX (just to be creative).
<p> Then you'd put your LOADLIN.EXE and as many different
kernels as you liked in that directory -- and maybe
a batch file (maybe it could be called LINUX.BAT) to
call LOADLIN with your preferred parameters. Here's a
typical LINUX.BAT:
<pre>
@ECHO OFF
ECHO "About to load Linux -- this is a one-way trip!"
PAUSE
LOADLIN lnx2029.krn root=/dev/sda1 ro
</pre>
<p> (where LNX2029.KRN might be a copy of the Linux-2.0.29
kernel -- with a suitable DOS name).
<p> I'd also recommend another batch file (SINGLE.BAT) that
loads Linux in single-user mode (for fixing things when
they are broken). That would replace the LOADLIN line
in the LINUX.BAT with a line like:
<pre> LOADLIN lnx2029.krn single root=/dev/sda ro
</pre>
<p> Another way to do all of this is to simply dd a
properly configured kernel to a floppy. You use the
rdev command to patch the root device flags in the
kernel and dump it to a floppy. This works because
a Linux kernel is designed to work as a boot image.
The only problem with this approach is that it doesn't
allow you to pass any parameters to your kernel (to
force single user mode, to select an alternate root
device/filesystem, or whatever).
<p> For other people who have a DOS system and want to
try Linux -- but don't want to "commit" to it with
a "whole" hard drive -- I recommend DOSLINUX.
<p> A while back there was a small distribution called
MiniLinux (and another called XDenu) which could
install entirely within a normal DOS partition --
using the UMSDOS filesystem. Unfortunately MiniLinux
has not been maintained -- so it's stuck with a 1.2
kernel and libraries.
<p> There were several iterations of a distribution called
DILINUX (DI= "Drop In") -- which appears to have eventually
evolved into DOSLINUX. The most recent DOSLINUX seems was
uploaded to the Incoming at Sunsite within the last two
weeks -- it includes a 2.0.29 kernel.
<p> The point MiniLinux and DOSLINUX is to allow one to install
a copy of Linux on a DOS system as though it were a DOS
program. DOSLINUX comes as about 10Mb of compressed
files -- and installs in about 20-30Mb of DOS file space.
It includes Lynx, Minicom, and a suite of other utilities
and applications.
<p> All in all this is a quick and painless way to try Linux.
So, if you have a DOS using friend who's sitting on the fence,
give them a copy of DOSLINUX and show them how easy it is.
<p><img align=bottom alt=" " src="../gx/ques.gif">
<P><B>
thanks!<br>
yash
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
You're welcome.
(Oh -- you might want to get those shift keys fixed --
e.e. cummings might sue for "look and feel")
<p>
--
Jim
<p><hr><p>
<!--================================================================-->
<a name="zmode"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
zmodem Reply
</h3>
From: Donald Harter Jr., <a href="mailto:harter@mufn.org">harter@mufn.org</a><br>
I saw your post about zmodem in the Linux Gazette. I can't answer the
readers question, but maybe this will help. My access to the internet is a
dial in account(no slip, no ppp). I access the freenets. I can't use
zmodem to transfer files from the internet and freeenets to my pc. I can
use kermit though. It seems that there are some control characters involved
in zmodem that prevent it from being used with my type of connection. I saw
a some information about this on one of the freenets. They suggested using
telix and another related protocol. I tried that, but it didn't work
either. Kermit is set up to run slow. You can get kermit to go faster in
certain circumstances by executing its "FAST" macro. I can download data at
about 700cps with the "FAST" macro of kermit. Unfortunately kermit hangs up
the line for me so I have to "kill -9 kermitpid" to exit it. That problem
can probably be eliminated with the right compile options. In certain cases
I can't use the "FAST" macro when uploading.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
I'm familiar with C-Kermit. In fact I may have an
article in the June issue of SysAdmin magazine on that very
topic.
<p> The main points of my article are that C-Kermit is a
telnet and rlogin client as well as a serial communications
program -- and that it is a scripting language that's
available on just about every platform around.
<p> I know about Telix' support for the kermit transfer protocol.
It sucks. On my main system I get about 1900 cps for
ZMODEM transfers -- about 2200 for kermit FAST (between
a copy of C-Kermit 5A(188) and 6.0.192 and about 70 cps
(yes -- seventy!) between a copy of C-Kermit and Telix'
internal kermit.
<p> Other than that I've always liked Telix. Minicom has
nice ncurses and color -- but is not nearly as featureful
or stable as either Telix for DOS or any version of C-Kermit.
<p> Your line hangups probably have to do with your settings for
carrier-watch. Try SET CARRIER-WATCH OFF or ON and see if
it still "hangs" your line. I suspect that its actually just
doing read() or write() calls in "blocking" mode. You might
have to SET FLOW-CONTROL NONE, too. There are lots of
C-Kermit settings. If you continue to have trouble -- post
a message to the comp.protocols.kermit.misc newsgroup
(preferred) or send a message to kermit-support@columbia.edu.
<p> When I first started using C-Kermit (all of about two months
ago) my initial questions where answered by Frank da Cruz
himself (he's the creator of the Kermit protocol and the
technical lead of the Kermit project at Columbia University).
(That was before he knew that I'm a "journalist" -- O.K.
quit laughing!). Frank is also quite active in the newsgroup.
I think he provides about 70 or 80 per cent of the technical
support for the project.
<p> Oh yeah! If you're using C-Kermit you should get the
_Using_C-Kermit_ book. It was written by Frank da Cruz and
Christine Gianone -- and is the principal source of funding
for the Kermit project. From what I gather a copy of the
book is your license to use the software.
<p>
--
Jim
<p><hr><p>
<!--================================================================-->
<a name="start"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
StartX
</h3>
<P> <B>
From: Robert Rambo, <a href="mailto:robert.rambo@yale.edu">robert.rambo@yale.edu</a><br>
Hi, I was wondering if you can help me out. When I use the command
'startx -- -bpp16' to change the color depth, the windows in X are much
bigger than the monitor display. So, nothing fits properly and
everything has become larger. But the color depth has changed
correctly. I use FVWM as my display manager. Is there some way to fix
this problem?
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
If using the 16 bit plan (16bpp) mode to increase
your color depth -- that suggests that selecting this
mode is causing the server to use a lower resolution.
<p> That is completely reasonable. If you have a 2Mb video
card and you run it in 1024x768x256 or 1024x768x16 --
then you try to run it with twice as many colors --
the video RAM has to come from somewhere. So it
bumps you down to 800x600 or 640x480. These are just
examples. I don't deal with graphics much so I'd have
to play with a calculator to figure the actual maximum
modes that various amounts of video RAM could support.
<p> There are alot of settings in the XConfig file. You
may be able to tweak them to do much more with your
existing video card. As I've said before -- XConfig
files are still magic to me. They shifted from blackest
night to a sort of charcoal gray -- but I can't do them
justice in a little article hear. Pretty much I'd have
to lay hands on it -- and mess with it for a couple of
hours (and I'm definitely not the best one for that job).
<p> If you haven't upgraded to a newer XFree86 (3.2?) then
this would be a good time to try that. The newer one
is much easier to configure and supports a better selection
of hardware -- to a better degree than the older versions.
I haven't heard of any serious bugs or problems with
the upgrades.
<p> You may also want to consider one of the commercial servers.
Definitely check with them in advance to be absolutely certain
that your hardware is supported before you buy. Ask around in
the newsgroups for opinions about your combination of hardware.
It may be that the XFree86 supports you particular card better
than Metro-X or whatever.
<p> You may also want to look at beefing up your video hardware.
As I've said -- I don't know the exact figures -- but I'd
say that you probably need a 4Mb card for anything like
16bpp at 1024x768. You should be able to look up the
supported modes in your card's documentation or on the
manufacturer's web site or BBS.
<B><P><img align=bottom alt=" " src="../gx/ques.gif">
Also, is there some way to change the color depth
setting to start X with a depth of 16 every time. I do not use the XDM
manager to initiate an X session.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
Yes -- it's somewhere in that XConfig file. I don't
remember the exact line. I really wish a bona fide GUI
X wiz would sign up for some of this "Answer Guy" service.
<p> It doesn't matter whether you use xdm or not. If you
put the desired mode in the XConfig file. However --
since you don't you could just write your own wrapper
script, alias or shell function to call 'startx' with
the -- -bpp16 options. You could even re-write 'startx'
(it is just a shell script). That may seem like cheating --
but it may be easier than fighting your way through the
XConfig file (do you get the impression that I just don't
like that thing -- it is better than a WIN.INI or a
SYSTEM.INI -- but not be much).
<p>
--
Jim Dennis,
<p><hr><p>
<!--================================================================-->
<a name="imap"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
IMAP and Linux
</h3>
<P> <B>
From: Brian Moore, <a
href="mailto:bem@thorin.cmc.net">bem@thorin.cmc.net</a><br>
Being a big IMAP fan (and glad to see it finally getting recognition:
Netscrape 4 and IE4 will both support it), your answer left a lot out.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
Will these support the real features (storing and
organizing folders on the server side)?
<p> I heard that NS "Communicator" (the next release
Netscape's Navigator series is apparently going to
come with a name change) supports IMAP -- but it's
possible to implement this support as just a variant
of POP -- get all the message and immediately
expunge all of them from the server.
<p> It seems that this is how Eric S. Raymond's 'fetchmail'
treating IMAP mail boxes -- as of about 2.5 (it seems
that he's up to 3.x now)
<P><img align=bottom alt=" " src="../gx/ques.gif">
<B>The easiest IMAP server to install is certainly the University of
Washington server. It works, handles nearly every mailbox format around
and is very stable. It's also written by the guy in charge of the IMAP
spec itself, Mark Crispin.
As for clients, there is always Pine, which knows how to do IMAP quite
well. This is part of most Linux distributions as well.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
I did mention pine. However it's not my personal favorite.
Do you know of a way to integrate IMAP with emacs mh-e/Gnus
(or any mh compatible folder management system)?
<P>
<img align=bottom alt=" " src="../gx/ques.gif">
<B>For GUI clients there is ML, which is a nice client, but requires Motif
and can be slow as sin over a modem when you have a large mailbox.
That's available in source at
http://www-CAMIS.Stanford.EDU/projects/imap/ml
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
I thought I mentioned that one as well -- but it's
a blur to me.
<p> I personally avoid GUI's like the plague. I'm
typing this from my laptop, through a null modem link
to my machine in the other room.
<p> I run emacs under screen -- so I can use mh-e for most
mail, Gnus for netnews and for some of my mailing lists
(it can show news folders as though they were threaded
news groups). screen allows me to detach my session from
my terminal so I can log out, take off with the laptop,
and re-attach to the same session later (via modem or when
I get back home).
<P>
<img align=bottom alt=" " src="../gx/ques.gif">
<B>Asking on the mailing list about static linked linux versions will get
you one (and enough nagging may get them to actually put one of the
current version up).
ML is really the nicest mail client I have ever used.
As for pop daemons with UIDL support, go for qpopper from qualcomm.
ftp.qualcomm.com somewhere. Has UIDL and works fine.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
O.K. I'll at that to my list.
<p> Does that one also support APOP's authentication
mechanism (which I gather prevents disclosing your
password over an untrusted network by using something
like an MD5 hash of your password concatenated with
a date and time string -- or something like that)?
<p> Does qpopper allow you to maintain a POP user account
file that's separate from your /etc/passwd file?
<p> Do you know of an IMAP server that supports these
sorts of features (secure authentication and separate
user base)?
<p> (I know this probably seems like a switch -- the
so called "Answer Guy" asking all the questions --
but hey -- I've got to get my answers from *somewhere*)
<p>
--
Jim
<p><hr><p>
<!--================================================================-->
<a name="imap2"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
More IMAP
</H3><P> <B>
From: Graham Todd, <a href="mailto:gtodd@yorku.ca">gtodd@yorku.ca</a>
<br>
PINE - one of the easiest to use mail clients around - does IMAP just
fine. You can read mail from multiple servers and mailboxes and save
it locally or in remote folders on the servers - which is what IMAP is
all about: Internet Message Access Protocol = flexible and
configurable *access* to mail servers without having to pop and fetch
messages all over the place (but still having the ability save locally
if you want).
</B>
<p><B>The Netscape's Communicator 4.0b2 thing does too but there are so many
other ugly bits that I'm not gonna bite.
</B>
<p><B>Jeez pretty soon with this fancy new IMAP stuff you'll be able to do
almost as much as you can right now with emacs and ange-ftp (which I
use regularly to access remote mail folders and boxes with out having
to login - it's all set up in .netrc).
Of course the answer is almost always "emacs" .... BTW Linux
makes a GREAT program loader for emacs ;-)
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
Seems kind of kludgey. Besides -- does that
give you the main feature that's driving the creation
of the IMAP/ACAP standards? Does it let you
store your mail on a server and replicate that to
a couple of different machines (say your desktop and
your laptop) so you can read and respond to mail "offline"
and from *either* system?
<P><B><img align=bottom alt=" " src="../gx/ques.gif">
Yeah, more or less. If you save the mail on your server to local
folders or make a local folder be /me@other.mail.host:/usr/spool/me.
Using ange-ftp to me seem exactly like IMAP in Pine or Netscape
communicator 4.0b2. Though apparently IMAP will update folders across
hosts so that only that mail deleted locally (while offline) will get
deleted on the remote host on the next login etc. etc. I don't know
much about IMAP's technical standard either but find I get equal mail
management capability from ange-ftp/VM. (equal to Pine and
Communicator so far).
</B>
<p><B>WARNING: In a week or so when I get time I'm gonna ask you a tricky
question about emacs and xemacs.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
Feel free. Of course I do know a bit more about emacs
than I do about X -- so you may not like my answer much.
<P><B><img align=bottom alt=" " src="../gx/ques.gif">
Heh heh OK...
(comp.emacs.xemacs is silent on this). Emacs running as emacs -nw in
a tty (i.e console or an xterm) runs fine and lets me use all the job
control commands (suspend/fg etc) but with Xemacs job control won't
work unless I'm running as root. That is if I'm running "xemacs" or
"xemacs -nw" in an xterm or at the console and do C-z and then once
I'm done in the shell I do "fg", xemacs comes back but the keyboard
seems to be bound to the tty/console settings (Ctrl-z Ctrl-s Ctrl-q
etc all respond as if I were in a dumb terminal). The only recourse
is to Ctrl-z back out and kill xemacs. This does not happen if I run
xemacs setuid root (impractical/scary) or as root (scary). Something
somewhere that requires root permission or suid to reset the tty
characteristics doesn't have it in xemacs - but does in emacs...
My only response so far has been that "you'll have to
rebuild/recompile your xemacs" - but surely this wrong. Does anything
more obvious occur to you? I feel it must be something simple in my
set up (RH Linux 2.0.29). Of course if I could get this fixed I'd
start feeling more comfortable not having GNU-Emacs on my machine ;-)
which may not be an outcome you would favour.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
I once had a problem similar to this one -- suspending
minicom would suspend the task and lock me out of it.
It seemed that the ownership of the tty was being
changed.
<p> So -- the question comes up -- what permissions are set on
your /dev/tty* nodes. It seems that most Linux distributions
are set up to have the login process chown the these to to the
current user (and something seems to restore them during or after
logout).
<p> I don't know enough about the internals of this process.
I did do a couple of experiments with the 'script' command
and 'strace' using commands like:
<pre> strace -o /tmp/strace.script /usr/bin/script</pre>
<p> ... and eyeballing the trace file. This shows how the
script command (which uses a psuedo tty -- or pty) searches
for an available device.
<p> I then did a simple 'chown 600 /dev/ttyp*' as root
(this leaves a bunch of /dev/ttyq* and /dev/ttyr nodes
available). The 'script' command then reports that
the system is "out of pty's."
<p> Obviously the script command on my system don't
do a very thorough search for pty's. It effectively
only looks at the first page of them.
<p> The next test I ran was to add a new line to my
/etc/services file (which I called stracetel) -- and
a new line to me /etc/inetd.conf that referred to it.
<p> This line looks like this:
<pre>
stracetel stream tcp nowait root /usr/sbin/tcpd \
/usr/bin/strace -o /root/tmp/t.strace /usr/sbin/in.telnetd
</pre>
<p> ... all on one line, of course.
<p> Then I connected to that with the command:
<pre> telnet localhost stracetel</pre>
<p> This gives me an strace of how telnetd handles the
allocation and preparation of a pty. Here, as I suspected,
I saw chown() and chmod() calls after telnetd did it's
search through to list of pty's to find the first one.
<p> Basically both programs (and probably most other
pty clients) attempt to open each pty until one returns
a valid file descriptor or handle. (It might be nice
if there was a system call or a daemon that would allow
programs to just say "give me a pty" -- rather than forcing
a flurry of failed open attempts -- but that's probably too
much to ask for.
<p> There result of these experiments suggests that there
are many ways of handling pty's -- and some of them may
have to be set as compile time options for your system.
<p> It may be that you just need to make all the pty's
mode 666 (which they are on my system) or you might
chgrp them to a group like tty or pty, make them mode
660 and make all the pty using programs on your system
SGID.
<p> I've noticed that all of my pty's are 666 root.root
(my tty's root.tty and ttyS*'s are root.uucp all are
mode 660 and all programs that need to open them are
either root run (getty) or SGID as appropriate).
<p> Some of the policies for ownership and permissions are
set my your distribution. Red Hat 2.x is *old* and
some of these policies may have changed in the 3.03 and
4.1 releases. Mine is a 3.03 with *lots* of patches,
updated RPM's and manually installed tarballs.
<p> Frankly I don't know *all* of the security implications
of having your /dev/tty* set to mode 666. Obviously
normal attempt to open any of these while they're in
use return errors (due to the kernel locking mechanisms).
Other attempts to access them (through shell redirection,
for example) seem to block on I/O. I suspect that a
program that improperly opened it's tty (failed to
set the "exclusive" flag on the open call) would be
vulnerable.
<p> Since you're an emacs fan -- maybe you can tell me --
is there an mh-e/Gnus IMAP client?
<P><B><img align=bottom alt=" " src="../gx/ques.gif">
No Kyle Jones (VM maintainer/author) has said maybe IMAP4 for VM
version 7. I think his idea is to make VM do it what it does well and
rely on outside packages to get the mail to it ...
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
Also -- isn't there a new release of ange-ftp --
I forget the name -- but I'm sure it changed named too.
<img align=bottom alt=" " src="../gx/ques.gif">
<P><B>
Yes it's called EFS - it preserves all the functionality but is more
tightly meshed with dired - supposedly it will be easier to use EFS in
other elisp packages (I don't know why or how this would be so).
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
I'll have to play with those a bit.
Can VM handle mh style folders?
<p>
--
Jim
<p><hr><p>
<!--================================================================-->
<a name="uucp"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
UUCP Questions
</h3>
<P> <B>
From: David J. Weis, <a
href="mailto:weisd3458@uni.edu">weisd3458@uni.edu</a><br>
I had a couple minor questions on UUCP. If you have a few minutes, I'd
appreciate the help immensely. I'll tell you a little bit about what we're
doing.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
Glancing ahead -- I'd guess that this would take quite a bit
more than a few minutes.
<P>
<img align=bottom alt=" " src="../gx/ques.gif">
<B>My company has a domain name registered (plconline.com) and two offices.
One is the branch office which is located in the city with the ISP. The
head office is kind of in the sticks in western Iowa. I've been
commissioned to find out how difficult it would be to set up the uucp so
the machine in Des Moines (the big city ;-) would grab all the domain mail
and then possibly make a subdomain like logan.plconline.com for all the
people in the main office to use email.
</B>
<p><B>This would all be running on RedHat 4 over dialup uucp. The system in Des
Moines uses uucp over tcp because it has to share the line with
masquerading, etc.
</B>
<p><B>Thanks for any advice or pointers you have.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif"><br>
Unfortunately I this question is too broad to answer
via e-mail. O'Reilly has a whole book on uucp and
there are several HOW-TO's for Taylor UUCP and
sendmail under Linux.
<p> My uucp mostly works but I haven't configured it to
run over TCP yet. I also haven't configured my
system to route to any uucp hosts within my domain.
<p> You can address mail to a uucp host through a
DNS by using the '%' operator. For example I can
get my main mail system (antares.starshine.org) to
forward mail to my laptop using an address like:
<pre> jim%mercury@starshine.org</pre>
<p> ... the DNS MX record for starshine.org routes
mail to my ISP. My ISP then spools it up in UUCP
until my machine (antares) picks it up. The
name antares is basically transparent to most of
this process.
<p> When antares gets the mail it converts the
percent sign into a "bang" (!) and spools it
for mercury (which happens to be my laptop).
<p> Obviously requiring all of your customers and
correspondents to use percent signs in their addressing
to your users is not going to work very well. It will
probably result in alot of lost mail, alot of complaints
and a constant barrage of support calls.
<p> There are two ways to make your internal mail routing
transparent to the rest of world. You can create a
master aliases list on your mail hub (the easy way) or
you can create DNS and MX entries for each of the hosts.
<p> If you'd like more help we could arrange to talk on
the phone. UUCP is difficult to set up for the first
time (nearly vertical initial learning curve). Once it's
set up it seems to be pretty low maintenance. However
my meta-carpus can't handle explaining the whole process
via e-mail (and I don't understand enough of it well to
be brief).
<p>
--
Jim
<p><hr><p>
<!--================================================================-->
<a name="flops"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Using MS-DOS Floppies
</h3>
<P> <B>
From: Barry, <a
href="mailto:remenyi@hotmail.com">remenyi@hotmailcom</a><br>
Hi, I have a problem that I can't find the solution to:
</B>
<p><B>I run Redhat 4.1 with mtools already installed, with it, I can copy a
file to or from a dos disk in A: with mcopy etc..
But if I change the disk & do mdir, it tells gives me the listing of
what was in the last disk. The only solution is to wait hours for the
cache to expire before I can look at another disk.
</B>
<p><B>The problem occurs no matter how I access the floppy, I also tried using
dosemu, and mount, but I have the same problem. I can read and write
from the first disk that I put in with no problems, but if I change the
disk, the computer acts as if the first disk is still in the drive. It
also doesn't matter who I am loged in as eg. root has the same problem.
I also upgraded mtools to 3.3 but no change.
</B>
<p><B>Is there some way to disable the disk cache (I assume thats the problem)
for the floppy drive?
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
You probably have a problem with the "change disk" detection
circuitry on your floppy.
<p> There's a pretty good chance that you'd see the same thing
under DOS too.
<p> Unfortunately I don't know of an easy way to solve this
problem. You could try replacing the floppy ($30 or so)
the controller ($20 -- to ???) and/or the cable.
<p> If that's not feasible in your case you could try something
like a mount/sync/umount (on a temporary mount point).
This might force the system to detect the new floppy. It's
very important not to try to write anything to a floppy when the
system is confused about which floppy is in there.
<p> DOS systems that I have used -- while they were afflicted
with this problem -- sometimes severely trash the directories
on a diskette in that situation.
<p> It probably doesn't even matter if the mount, sync, umount
that I describe fails -- just so the system is forced to
"rethink" what's there. I'd consider writing a short script
to do this -- put a temporary mount point that's "user" accessible
to avoid having to be root to do this (and especially to avoid
having to create any SUID root perl scripts or write a C wrapper
or any of that jazz).
<p> Here's a sample line for your /etc/fstab:
<pre># /etc/fstab
/dev/fd0 /mnt/tmp umsdos noauto,rw,user 0 0</pre>
<p> (according to my man pages the "user" options should
imply the nosuid, nodev etc. options -- which prevent
certain other security problems).
<p> So your chdisk script might look something like:
<pre> #! /bin/sh
/bin/mount /mnt/tmp
/bin/sync
/bin/umount /mnt/tmp</pre>
<p> ... you could also just do a 'mount /mnt/tmp' or a
'mount /mnt/a' or whatever you like for your system --
and just use normal Linux commands to work with those
files. The mtools are handy sometimes -- but far from
indispensable on a Linux system with a good fstab
file.
<p> As a security note: mount must be SUID in order to
allow non-root users to mount filesystems. Since
there have been security exploits posted on mount
specifically and various other SUID files chronically,
I suggest configuring mount and umount such that they
can only be executed by members of a specific group
(like a group called "disk" or "floppy"). Then you
can add yourself and any other users who have a valid
reason to work at your console to that group. Finally
change the permissions on mount and umount to something
like:
<pre> -r-sr-x--- 1 root disk .... /bin/mount</pre>
<p> .... i.e. don't allow "other" to execute it.
<p> This also applies to all your SVGALib programs (which
should not be executed except from the console) and
as many of your other SUID programs as you can.
<p> (... it would be nice to do that to sendmail -- and
I've heard it's possible. However it's a bit trickier
than I've had time to mess with on this system).
<p> As PAM (pluggable authentication module) technology
matures you'll be able to configure your system to
dynamically assign group membership's based on
time of day and source of login (value of `tty`).
<p> This will be nice -- but it doesn't appear to be
quit ready yet.
<p>
--
Jim
<P><B>
<img align=bottom alt=" " src="../gx/ques.gif">
I just wanted to write to thank you for you response to my mail.
I did as you suggested and the problem is solved!
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
Actually, you were also right about the problem occurring in DOS as
I used to have a lot of floppies go bad before I went all the way
to linux, but I didn't make the connection.
<P><B>
<img align=bottom alt=" " src="../gx/ques.gif">
Anyway, thanks again, you've made my day!
</B>
<p><B>Barry
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
You're welcome. I'm glad it wasn't something complicated.
BTW: which suggestion worked for you? Replacing one or
another componenent? Or did you just use the "mount, sync,
umount" trick?
<p> Under DOS I used to use Ctrl-C, from the COMMAND.COM A:
prompt to force disk change detection. You can use that
if you still boot this machine under DOS for some work.
<p>
--
Jim
<p><hr><p>
<!--================================================================-->
<a name="inetd"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
inetd Questions
</h3>
<P> <B>
From: Benjamin Peikes, <a href="mailto:benp@npsa.com">benp@npsa.com</a><br>
Answer guy,<br>
I have two questions for you.
</B>
<p><B> 1) I'm using one machine with IPAliasing and was wondering if
there is a version of inetd built so that you can have different
servers spawned depending on the ip number connected to.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
That's an excellent question.
There is apparently no such feature or enhanced version of
inetd or xinetd.
<p> It also doesn't appear to be possibly to use TCP Wrapper
rules (tcpd, and the /etc/hosts.allow and /etc/hosts.deny)
to implement this sort of virtual hosting.
<p> So far it appears that all of the support for virtual hosting
is being done by specific applications. Apache and some other
web servers have support for it. The wu-ftpd's most recent
versions support it.
<p> I suspect that you could create a special version of
inetd.conf to open sockets on specific local IP addresses
and listen on those. I would implement that as a command
line option -- passing it a regex and/or list of ip addresses
to listen on after the existing command line option to
specify which configuration file to use. Then you'd load
different copies of this indetd with commands like:
<pre> /usr/sbin/inetd /etc/inetd.fred 192.168.14.0 17.18.0.0
/usr/sbin/inetd /etc/inetd.barney barneyweb
/usr/sbin/inetd /etc/inetd.wilma 192.168.2.3
</pre>
<p> (This would be something like -- all of the 192.168.14.*
address and all of the 17.18.*.* addresses are handled by
the first inetd -- all of the access to a host named
barneyweb (presumably looked up through the /etc/hosts file)
would be handled by the next inetd. and all of the accesses
to the ipalias 192.168.2.3 would be handled by the last one)
<p> This would allow one to retain the exact format of the
existing inetd files.
<p> However I don't know enough about sockets programming to
know how much code this would entail. The output of
'netstat -a' on my machine here shows the system listening
on *:smtp and *:telnet (among others). I suspect that those
stars would show up different if I had a socket open to
a specific service on a specific service.
<p> This scheme might use up to many file descriptors. Another
approach would be to have a modified tcpd. This would have
to have some option where by the destination *as well as*
the source was matched in the /etc/tcpd.conf file(s).
<p> (Personally I think that tcpd should be compiled
with a change -- so that the single tcpd.conf
file is used in preference to the /etc/hosts.allow
and /etc/hosts.deny files. Current versions do
support the single conf file -- but the naming is
still screwy).
<p> I'm not sure quite how Wietse would respond to this --
possibly by repeating the question:
<p> "If you want me to add that -- what should I
take OUT?"
<p> (which is what he said one to me when I suggested merging
his chrootuid code with tcpd).
<p> I've blind copied Wietse on this (Hi!). I doubt he has
time to read the Linux Gazette.
<P>
<img align=bottom alt=" " src="../gx/ques.gif">
<B>2) A related problem: I have one machine running as a mail server
for several domains where the users are using pop to get their
mail. The problem is that the From: line always has the name
of the server on it. Is there a way to use IPaliasing to fix
this? Or do I have to muck around with the sendmail.conf file?
</B><P>
<p> This is becoming a common question.
<p> Here's a couple of pointers to web sites and FAQ or HOWTO
documents that deal specifically with "Virtual Mail Hosting"
<ul>
<li><a href="http://www.sinbad.wantabe.com/virtualmail">How to Set up Sendmail for Virtual Domains</a>
<li><a href="http://www.qmail.org">qmail: A Replacement for Sendmail</a>
</ul>
<p> (look for references to "virtualdomains")
<p> ... and here's one guide to Virtual Web Hosting:
<ul>
<li><a href="http://inorganic5.fdt.net/ldp/HOWTO/mini/Virtual-Web">
Virtual Web Mini-HOWTO</a>
</ul>
<P>
<img align=bottom alt=" " src="../gx/ques.gif">
<B>I guess the best way to do this would be to change inetd to figure
out on which interface the connection has been made on and then
pick the correct inetd.conf to reference, like
<pre>
inetd.conf.207.122.3.8
inetd.conf.207.122.3.90</pre>
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
I would recommend that as a default behavior.
I suggested adding additional parameters to the
command line specifically because it could be done
without breaking any backward compatibility. The
default would be to simply work as it does now.
<p> I still suspect that this has some scalability problems
-- it might not be able to handle several hundred or several
thousand aliased addresses.
<p> I might still be useful to implement it as a variation of --
or enhancement to -- tcpd (TCP_Wrappers).
<P>
<img align=bottom alt=" " src="../gx/ques.gif">
<B>I think that inetd reads in the configuration file when it
starts because it needs a SIGHUP to force it to reread the conf
file. All you would have to do is make it reference the right table.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
This is also documented in the inetd man page.
<P>
<img align=bottom alt=" " src="../gx/ques.gif">
<B>Do you know where I could find the code? I would be interested
in looking at it?
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
The source code from inetd should be in the bundle
of sources that comes with the "NetKit"
<p> Look to:
<p><a href="ftp://ftp.inka.de/pub/comp/Linux/networking/NetTools/">ftp:..ftp.inka.de/pub/comp/Linux/networking/NetTools/</a>
<p> and mirrored at:
<p><a href="ftp://ftp.uk.linux.org/pub/linux/Networking/PROGRAMS/NetTools/>ftp://ftp.uk.linux.org/pub/linux/Networking/PROGRAMS/NetToos/</a>
<p> More information about Linux network code can be
found at:
<p><a href="ftp://sunsite.unc.edu/pub/Linux/system/network/NET-3-HOWTO">ftp://sunsite.unc.edu/pub/Linux/system/network/NET-3-HOWTO/</a>
<p> ... this includes the history of it's development and the
names of people who were active in it at various stages.
<p> If you're going to try to hack this together -- I'd suggest
a friendly posting to the comp.linux.development.system
newsgroup -- and possibly some e-mail to a couple of
carefully chosen people in the NET-3-HOWTO.
<p>
--
Jim
<p><hr><p>
<!--================================================================-->
<a name="modem"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Navas Modem FAQ
</h3>
<P> <B>
From: John Doe
<br>
The next time you answer a modem question, you'd do well
to recommend reading of the very good Navas Modem FAQ at
<a href="http://www.aimnet.com/~jnavas/modem/faq.html">http://www.aimnet.com/~jnavas/modem/faq.html/</a>
</B><P><img align=bottom alt=" " src="../gx/ans2.gif">
Well, here's someone who wants to make a anonymous
tip to "The Answer Guy."
<p>At "John Doe's" request I looked over this site. It
does have extensive information about modems -- including
lots of press releases about which companies are acquiring
each other (3Com over US Robotics, Quarterdeck gets DataStorm).
<p>However there didn't appear to be any references to Linux,
Unix or FreeBSD.
<p>So -- if one needs information about modems in general this
looks like an excellent site to visit. However it the question
pertains specifically to using your modem with Linux -- I'd
suggest:
<a href="http://sunsite.unc.edu/LDP/HOWTO/Serial-HOWTO.html">http://sunsite.unc.edu/LDP/HOWTO/Serial-HOWTO.html</a>
<p>
--
Jim
<p><hr><p>
<!--================================================================-->
<a name="modem2"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Setting Up a Modem
</h3>
<P> <B>
From: Yang, <a href="mailto:lftian@ms.fudan.edu.cn">lftian@ms.fudan..edu.cn</a>
</br>
I have an AT 3300 card( from Aztech) which integrates the function of
sound card and 28.8K modem. It seems that it need a special driver for its
modem function to be work. In MSDOS, there is a aztpnp.exe for that
purpose. Do you know is there any way I can get the card work (at least its
modem function) in Linux?
</B><p>
<B>Tianming Yang
</B><P><img align=bottom alt=" " src="../gx/ans2.gif">
I'm not familiar with that device. The
name of the driver suggests that this is a
Plug 'n Play (pnp) device (sometimes we use the
phrase "plug and *pray*" -- as it can be a toss
of the dice to see if they'll work as intended.
<p> My guess would be that this is a PCMCIA card
for a laptop system (which I personally pronounce
"piecemeal").
<p> Did you look in the "Hardware HOWTO" (start at
www.ssc.com, online mirror of FAQ's and HOWTO's)?
<p> Did you go to Yahoo! and do a keyword search on
the string:
<pre> linux +aztech</pre>
<p> ... (the plus sign is important there)?
<p> Since all of the real details about the configuration
of the card are determined by the manufacturer
(Aztech in this case) I would start by contacting
them.
<p> If they've never heard of Linux -- or express no
interest in supporting it -- please consider letting
them know that Linux support affects your purchasing
decisions. Also let them know that getting support
for Linux is likely to cost them very little.
<p> How to get a Linux driver for your hardware:
<p> If you are a hardware company that would like
to provide support for Linux and FreeBSD and other
operating systems -- but you don't have the
development budget -- just ask.
<p> That's right. Go to the comp.os.linux.development.system
newsgroups and explain that you'd like to provide
full documentation and a couple of units of your hardware
to a team of Linux programmers in exchange for a freely
distributable driver. Be sure to make the sources for
one of your other drivers (preferably any UNIX, DOS, or
OS/2 driver) available to them.
<p> If you don't like that approach, consider publishing the
sources to your existing drivers. If you are really in
the hardware business than the benefits of diverse OS
support should far outweigh any marginal "edge" you might
get from not letting anyone see "how you do it."
<p> (Just a suggestion for all those hardware vendors out there).
<p>
--
Jim
<p><hr><p>
<!--================================================================-->
<a name="userid"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
User Identification
</h3><P> <B>
From: Dani Fricker, <a
href="mailto:101550.3160@CompuServe.COM">101550.3160@CompuServe.COM</a>
<br>
i need your help. for some reasons i have to identify a user on my
webserver by his/her ip-address. fact is that users logon comes from
different physical machines. that means that i have to assign something
like a virtual ip-address to a users log name. something like a reversal
masquerading.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
The IP Address of any connecting client is provided
to any CGI scripts you run, and is stored in the
server's access log (or a reverse DNS lookup of it
is stored therein -- depending on your httpd and
configuration).
<p> * Note: I suggest disabling reverse DNS
lookup on webserver wherever possible.
it generates alot of unnecessary traffic
and you can isolate, sort, and look up the
IP addresses in batches when you want to
generate statistics involving domain names.
<p> (I also tend to think that most of the
reports done on web traffic logs have about
as much rigor and resemblance to statistical
analysis as reading chicken entrails).
<P>
<img align=bottom alt=" " src="../gx/ques.gif">
<B>my ip-gateway connects my inner lan over two token ring network cards
(sorry, not my idea!) with the internet (lan <-> tr0 <-> tr1 <->
internet). the masquerading forward roule of ipfwadm gives me the
possibility to indicate a source and a destination address.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
Oh. So all of the clients that you're interested in
are on a private LAN and going through a masquerading/NAT
server (network address translation).
<p> I would try using ident for starters. Run identd on your
Masquerade Host and make calls to the ident service from
your CGI scripts. I don't think it will work -- but it
should be worth a little info.
<p> From there you might be able to configure all the clients
on the inner LAN to use an *applications* level proxy
(squid -- formerly cached, CERN httpd, or the apache cache/
proxy server). Masquerading can be thought of as a
"network layer proxying services" while SOCKS, and similar
services -- which work with the co-operation of the client
software -- are applications layer proxies.
<p> I don't know if the private net IP address or other info
will propagate through any of these HTTP proxies.
<p> If this is *really* important to you, you could consider
writing your own "NAT Ident" service and client. I don't
know how difficult that would be -- but it seems like the
code for the identd (and the RFC 931? spec) might give you
a starting point for defining a protocol (you might want
to secure that service under TCP_Wrappers). You might want
to consider making this a TCP "Multiplexed" service --
look for info on tcpmux for details about that.
<p> The gist of tcpmux is that it allows your custom client
to talk to a daemon on TCP port 1 of the server host and
ask for a service by name (rather than relying on
"Well-Known Port Addresses"). So, if you're going to create
a new service -- it makes sense to put it under tcpmux
so you don't pick your own port number for it -- and then
have the IANA assign that port to something else that you
might want later.
<P><img align=bottom alt=" " src="../gx/ques.gif">
<B>do you see a possibility for an 'address assignment' between the two
interfaces? if you do please let me know.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
I don't know of any existing way to determine the IP
address of a client on the other side of any NAT/masquerading
host -- I'm not even sure if there's any existing way to do it
for a client behind a SOCKS or TIS FWTK or other applications
level proxy.
<p> I'll be honest. With most "Answer Guy" questions I
do some Yahoo!, Alta-vista and SavvySearch queries -- and
ask around a bit (unless I already know the answer pretty
well -- which doesn't happen all that often these days).
I skipped that this time -- since I'm pretty sure that
there's nothing out there that does this.
<p> I welcome any corrections on this point. I'll be happy
to forward any refutations and corrections to Dani.
<p> All of this begs the greater question:
<p> What are you really trying to do?
<p> If you are trying to provide some form of transparent
access control to your webserver (so local users can
see special stuff without using a "name and password")
-- there are better ways available.
<p> Netscape and Internet Explorer both support a form
of client-certificate SSL -- which is supported at
the server side by the Stronghold (commercial Apache)
server.
<p> As an alternative -- I'd look at the possibility of
finding or writing a Kerberos "auth" module for
Apache (and deploying Kerberos to the clients).
This might be more involved than you're management
is willing to go for -- but writing new variations of
the indentd service might also fall into that category.
<p> IP addresses are a notoriously bad form of access
control. If you have a properly configured set of
anti-spoofing rules in the packet filters on your
router -- and you can show that no other routes exist
into your LAN -- then you can base access controls to
services (TCP/Wrappers) to about the granularity of
"from here" and "not from here." Attempting to read
more into them than that is foolhardy.
<p> Ethernet and Token Ring MAC (media access control) addresses
(sometimes erroneously called "BIA's" -- burned in addresses)
are just about as bad (most cards these days have options to
over-ride the BIA with another MAC -- usually a feature of
operating the card in "promiscuous" mode).
<p> Yet another approach to the problem might be to simply
put a web server on the internal LAN (no routing through
the NAT/masquerading host) -- and use something like
rdist to replication/mirror the content between the
appropriate document trees on the internal and exterior
web servers.
<p> Basically we'd need to know much more about your
requirements in order to give relevant recommendations.
<p>
--
Jim
<p><hr><p>
<!--================================================================-->
<a name="duplic"></a>
<h3><img align=bottom alt=" " src="../gx/ques.gif">
Duplicating a Linux Installed HD
</h3><P> <B>
From: Mohammad A. Rezaei, <a href="mailto:rezaei@tristan.TN.CORNELL.EDU">rezaei@tristan.TN.CORNELL.EDU</a><br>
I just read your response to duplicating a hard drive using dd.
I think using dd limits the uses of this technique too much.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
I absolutely agree. I wonder where I suggested 'dd'
without expressing my misgivings.
<p> Please consider quoting little portions of my posting
when making references to them -- I write alot and
can't remember past postings without some context.
<P>
<img align=bottom alt=" " src="../gx/ques.gif">
<B>I have more than once installed/transfered entire hard drives using
tar. simply put both drives in the same machine, mount the new drive
in /mnt and do something like
<pre>
tar -c -X /tmp/excludes -f / | (cd /mnt; tar xvf -)
The file....
/tmp/excludes should contain:
/mnt
/proc
and any other non-local, mounted drives, such as nfs mount points.
</pre>
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
There are better ways to do this.
One way is to use a command like:
<pre>
find ... -xdev -type f | tar cTf - - | \
(cd ... && tar xpf - )
Another is to use:
find ... | cpio pvum /new/directory
... which I only learned after years of using
the tar | (cd ... && tar) construct.
</pre>
<p> In both of these cases you can use find parameters
to include just the files that you want. (Note:
with tar you *must* prevent find from printing any
directory names by using the -type f (or more
precisely a \! -type d clause) -- since tar will
default to tar'ing any directories named in a
recursive fashion).
<p> The -T (capital "tee") option to GNU tar means to
"Take" a list of files as an "include" list. It
is the complement to the -X option that you list.
<p> You can also pipe the output of your find through
grep -v (or egrep -v) to filter out a list of
files that you want to exclude.
<P><B><img align=bottom alt=" " src="../gx/ques.gif">
finally, one has to install the drive onto the new machine,
boot from floppy and run lilo.
The disks don't have to be identical. the only disadvantage is having
to run lilo, but that's takes just a few minutes.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
The only message I can remember posting about 'dd'
had an extensive discussion of using tar and cpio for
copying trees.
Am I forgetting one -- or did you only get part of
my message?
<P><B><img align=bottom alt=" " src="../gx/ques.gif">
Hope this helps.
</B><P>
<img align=bottom alt=" " src="../gx/ans2.gif">
Hopefully it will help some readers. The issues of
copying file trees and doing differential and
incremental backups is one that is not well covered in
current books on system administration.
<p> When I do a full backup I like to verify that it
was successful by extracting a table of contents or
file listing from the backup media. I then keep a
compressed copy of this. Here I use tar:
<pre>
tar tf /dev/st0 | gzip > /root/tapes.contents/.....
</pre>
<p> .... where the contents list is named something like:
<pre>
antares-X.19970408
</pre>
<p> .... which is a hostname, a volume (tape) number and a
date in YYYYMMDD format (for proper collation -- sorting).
<p> To do a differential I use something like:
<pre> find / -newer /root/tape.contents/.... \
| egrep -v "^(/tmp|/proc|/var/spool/news)" \
| tar czTf - /mnt/mo/diff.`date +%Y%m%d`.tar
</pre>
<p> ... (actually it's more complicated than that since
I build the list and compute the size -- and do some
stuff to make sure that the right volume is on the
Magneto Optical drive -- and mail nastygrams to myself
if the differential won't fit on that volume -- if the
volume is the most recent one (I don't overwrite the
most recent -- I rotate through about three generations)
-- etc).
<p> However this is the core of a differential backup.
If you wanted an incremental -- you'd supply a different
file to the -newer switch on your find command.
<p> The difference between differential and incremental is
difficult to explain briefly (I spent about a year
explaining it to customers of the Norton Backup). Think of
it this way:
<p> If you have a full -- you can just restore that.
<p> If you have a full, and a series of differentials,
you can restore the most recent full, and the
most recent differential (any older fulls or differentials
are unneeded)
<p> If you have a full and a series of incrementals you
need to restore the most recent full, and each
subsequent incremental -- in order until the most
recent.
<p> It's possible (even sensible in some cases) to use a
hybrid of all three methods. Let's say you have a large
server that takes all day and a rack full of tapes to do a
full backup. You might be able to do differentials for
a week or two on a single tape per night. When that fills
up you might do an incremental, and then go back to
differentials. Doing this to a maximum of three incrementals
might keep your all day backup marathons down to once a month.
The restore must go through the "hierarchy" of media in the
correct order -- most recent full, each subsequent incremental
in order, and finally the most recent differential that was
done after that.
<p> (Personally, I avoid such complicated arrangements like the
plague. However they are necessary in some sites.)
<P>
-- Jim
<!--================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1997, James T. Dennis <BR>
Published in Issue 17 of the Linux Gazette May 1997</H5></center>
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&quot;Linux Gazette...<I>making Linux just a little more fun!</I>&quot;
</H4>
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<center>
<H2>CLUELESS at the Prompt: A Column for New Users<\H2>
<H4>By Mike List,
<a href="mailto:troll@net-link.net">troll@net-link.net</a>
</center>
<P> <HR> <P>
<center><IMG ALIGN=MIDDLE SRC = "../gx/list/gnub.jpg" ></center>
<p>
<h4>Welcome to installment 4 of Clueless at the Prompt:
a new column for new users.</h4>
<hr>
<p><h4> Connecting to a Second ISP...or Third, or</h4>
I recently got e-mail from a guy who wanted to know how to connect to a
second ISP.His e-mail address apparently wasn't valid, and it got bounced
back several times. Just as well, since I didn't have the answer at that
point. Well, I got this idea, and I tried it and it works.Here's the deal:
First,
<pre> cp /usr/sbin/ppp-on to /usr/sbin/ppp-on.anysuffix
</pre><p>
Then open the file you just created with a text editor, and change any
information that applies to the secondary ISP, eg. dialup, the IP number
of the ISP, username and password. write the file(save it) and try your
new executable, ppp-on.anysuffix. Just a quick pointer, you could call
your new script any name you want as long as there's no other file with
the same name in your path,preferably no other file with the same name at
all
<hr>
<h4> Dealing With a Dynamic IP</h4>
<p>
These days most Internet Service Providers assign you a Dynamic IP when
you logon to their network, due to the cost of assigning every customer
a static IP. At present there are only so many IP addresses available
and, apparently each one costs to register. Consequently ISPs buy a pool
of IP addresses within a range and assign an available one at login. For
most uses, such an arrangement is no problem, assuming that most
internet usage consists of interaction between the ISP's computer and
the local one. For some purposes, however such as allowing telnet or ftp
to your computer the dynamic scheme is less than ideal. Here's
a relatively painless way to get your current IP, so you can run with
the big dogs. Open an xterm, or rxvt and type:
<pre> ifconfig</pre><p>
which will bring up some info in two blocks. You'll want to note the
bottom block, which will have a line that specifies your inet address
expressed numerically. It will be in a xxx.xxx.xxx.xxx format, which
corresponds to the standard IP address, in fact that's what it is.
you ca write this number down or just highlight this IP address(to paste
it)and type:
<pre>nslookup the.num.ber.</pre><p>
the number being your inet address from the last step.
It may take a couple of minutes, but you will get a two line messagethat
looks like:<pre>Name: your Fully Qualified Domain Name
Address: IPa.ddr.ess.!!! </pre><p>
we may talk about FQDN some more another time, but for the purpose at
hand, just type:
<pre>hostname Name</pre><p>
where Name is the first line from the above step. That's it, except that
you must repeat this procedure every time you connect to your ISP. You
might be able to write a script to automate this procedure, but in the
meantime which as my friend Al used to say "is a groovy time", you can
use this knowledge to run remote X apps(just a minute,I'm coming to that)
allow your friends or inet associates to telnet to your computer, or ftp
files from a telnetted site(this too, momentarily).What you need to know
is that the next time youreboot, you may get a message saying that your
computer name is "bad". This isn't a comment on your lack of originality
or taste, and you should basically ignore it.
<hr>
<h4>Using your Domain Name</h4>
If you have a shell account at a computer located at a university or
school near you, this will amaze you. Oh yeah not, by way of a plug, but
there is a semi commercial telnet box called linuxware.com(you will have
to look up the URL yourself semi- plug, you might say, I'm a subscriber)
What am I talking about? Using X to run apps from the remote computer on
your screen. You can actually run a program that isn't installed on your
computer, in X with the remote computer supplying the program. I think
it embodies the essence of networking, with permissions set right, you
can co-author a document, play a multi-user game (MUD)use a
talkprogram, like ytalk, or do office or school work from your home
computer.Here's what you need to do. First, you need to know and have
your FQDN listed by typing:
<pre>hostname</pre><p>
as detailed above. If you have a static IP address, you can skip this
step.What needs to be done next is to type:
<pre>xhost + the.telnet.box</pre><p>
When you hit enter you will see a message like, "the.telnet.box has been
added to the control list". You will probably have to restart your window
manager, your mileage may, as they say, vary. Now when you start a
telnet session, you can enter the name of an X application and in a
moment, the application window will apear on your screen, even if you
don't have it installed on your computer. Do your work, play your game,
and marvel at the ramifications of this capability.
<p> You can also invite friends and coworkers over to your computer to
do some work, socialize or learn something, in the following manner.
Obtain your FQDN, or IP address, as detailed above. E-mail it to them or
call them on the phone to let them know where you are today(Not where
you want to go today, that's another "OS"). they can then:
<pre> telnet FQDN or ftp IPa.ddr.ess.!!!</pre><p>
and all of a sudden they're in your den, or office or wherever you keep
your computer. For more sophisticated methods of getting your address,
read the "Dynamic IP hacks-HOWTO.
<h4>Just a Reminder: Read the whole Linux Gazette</h4>
<p>This esteemed tabloid is just full of novice- to intermediate level
tips and tricks.The Answer Guy, Two Cent Tips, and The Weekend Mechanic
in particular, are good sources of the kinds of things that will make you
a demi-guru in no time at all.
<hr>
<h4>Formatting Floppy Disks in Linux</h4>
<p>In DOS and Windows,formatting a floppy disk is a one shot affair
which formats, erases data, and creates a file system on the floppy.
In linux however, you have to format and create the filesystem in
separate steps. At first glance, this seems backward, after all, isn't
linux a more sophisticated OS? Why do things in two steps that the others
do in one? The reason is that linux can read several filesystems so that
data can be moved from one OS to the other. By mounting the floppy drive
as MSDOS, VFAT, or other filesystem type the data can be read from the
mount point in a manner that linux can make use of.
<hr>
<h4>Other Stuff I've Collected/Found out Since Last Time</h4>
<p>have trouble with the
<pre> find </pre><p>command?Try leaving your computer on overnight, and
the next day use the <pre>locate /filename |less</pre><p>command instead.
Locate is a database that is gathered during idle times on your computer
Actually locate reads a database that is updated by a command in your
system files, but if you give it time to breathe, usually overnight, it
can locate any file on your hard drive(s). You can also try
<pre> whereis filename </pre><p>
and you will get a location for the named file.
<hr>
Next Time- Let me know what you would like to see in here and I'll
try to
oblige just e-mail <a href="mailto:troll@net-link.net">troll@net-link.net</a>
me and ask, otherwise I'll just write about what gave me trouble and
how I got past it.</p>
<p> TTYL, Mike List </p>
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1997, Mike List <BR>
Published in Issue 17 of the Linux Gazette, May 1997</H5></center>
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<H4>By Jesper Pedersen,
<a href="mailto:blackie@imada.ou.dk">blackie@imada.ou.dk</a></H4>
</center>
<P> <HR> <P>
<P> In this article I will describe a configuration tool called The Dotfile
Generator (TDG for short). TDG is a configuration tool, which configures
programs, using X11 widgets like check boxes, entries, pull-down menus etc.<p>
For TDG to configure a given program a module must be made for it. At the
moment modules exist for the following programs: Bash, Fvwm1, Fvwm2, Emacs,
Tcsh, Rtin and Elm.<p>
The article will describe common use of TDG, so if you do not have it yet,
it might be a good idea to <a
href="ftp://ftp.imada.ou.dk/pub/dotfile/dotfile.tar.gz">download
it</a> (It's free!) You may also go to <a
href="http://www.imada.ou.dk/~blackie/dotfile/">the home page of the
Dotfile Generator</a> for further information.
<p><hr><center><h1>Intro</h1></center>
The UNIX system, was developed many years ago, long before
graphical user interfaces became commonplace. This means that most of the applications
today work fine without a graphical user interface. Examples of this are
editors and shells.<p>
A basic concept in UNIX is that the programs are very configurable. Here is
an example from Emacs, which shows this:<p>
<blockquote>
<i>What should be done if the user asks to go to the next line at the of</i>
a file?<br>
There are two logical
possibilities: <ol>
<li> Insert a blank line, and move to it.
<li> Beep, to tell the user that there is no next line.
</ol>
Instead of implementing only one of the solution the people behind Emacs,
have chosen to implement both, and let you decide which one you prefer.
</blockquote>
Since the program works without a GUI, the standard method for
configuring such options is to use a <i>dot-file</i>. In this file, you
may <i>program</i>, which method you will use.<p>
This solution, however, requires that the user has to learn the programming
language used in the dot-file, and has to read lots of documentation to
find out which configurations can be made. This task may be difficult and
tedious, and for that reason many users often choose to use the default
configuration of the program.<p>
If you take a look at some dot-files, you may find
that most of the configurations can be described by the following items:
<ul>
<li> Configurations with two possibilities (like above)
<li> Configuration, where the program wishes to know a number or text.
Examples of this could be questions like: <i>how many times should
one press CTRL-d to quit</i>, and <i>email address to use in
reply-to field</i>.
<li> Configuration, where the user may choose an option from a list, eg:<br>
<i>which editor would you like to use: emacs, jed, vi or vim</i>
</ul>
The configurations above may easily be done with a GUI, with the following
widgets in order: A check box, an entry and a pull down menu.
This is exactly what is done in TDG.
<p><hr><center><h1>The basic concept of TDG</h1></center>
TDG is a tool, which configures other programs (eg. emacs,bash and fvwm)
with widgets as those described above, and many more. The widgets are
placed in groups, which makes it easy to find the correct configuration
without having seen it before. And most important of all, help is located
at the configuration of each option, instead of in a manual far away. To get
help, you just press the right mouse button on the widget, which contains
the configuration you want to know more about!<p>
When you start TDG, you will be offered a list of standard configurations,
where you may pick one to start out with. This may be convenient, if you do
not have a dot-file for the given program, or if you would like to try a
new configuration. If on the other hand, you already have a dot-file, which
you would like to put the finishing touches to, you may read this file into
TDG. Note, however, that it is not all modules, which have the capability
to read the dot-file (the fvwm2, rtin and elm modules have, the other
modules do not, since it would be to complicated to create such a
parser.)<p>
When you have selected a start-up configuration, the menu-window will be
displayed (see figure 1). In this window, you can travel through the
configuration pages, just like a directory structure. If you select a
page, a new window will be displayed, with the configuration for this page
(see figure 2). This window will be reused for all the configuration pages,
ie. only one configuration page is visible at a time, so you do not have
to destroy the window yourself.<p>
<table CELLSPACING=1 CELLPADDING=4 cols=2 width=100%>
<tr>
<td align=top>
<center><img width=294 height=196 src="./gx/pedersen/menu_window.jpg"><p>Figure 1</center>
<td align=top>
<center><img width=399 height=203 src="./gx/pedersen/config_page.jpg"><p>Figure 2</center>
</table>
In region 1, the actual configuration is located. Region 2 is the help
region. In this region help for the whole page is shown, when the window is
displayed. It's also here, help for the individual configuration is
shown, when you press the right mouse button on one of the widgets.<p>
In region 3, information is shown on what will be generated. You have
three possibilities:
<ol>
<li> You may generate all pages. This is the most natural thing to do,
when you just want a configuration for a given program.
<li> You may generate just the page shown. This is useful if you are
plying around with TDG to see what will be generated for the
different configurations.
<li> Finally you may tell TDG, to just generate some of the pages, which
is done with radio buttons in this region.
</ol>
In the <tt>Setup</tt>-><tt>Options</tt> menu, you may select which of the
three methods above will be used.<p>
When you have done all the configurations, you have to tell TDG which file
you wish to generate. This is done from the Options menu
(<tt>Setup</tt>-><tt>Options</tt>). And now it's time to create the actual
dot-file, which is done by selecting <tt>Generate</tt> in the <tt>File</tt>
menu.<p>
Once you have generated the dot-file, you may find that you would like some
of the configuration to be different. You could now go to the configuration
page in question, change your configuration, and then generate once again. If,
however, you are testing several different options for a single
configuration (ie. several items from a pull-down menu) you may find it
cumbersome to generate the whole module over and over again. In this
situation, you may chose <tt>Regenerate this page</tt> in the <tt>File</tt>
menu. Note, however, that if some part of the configurations on the page effects
other pages, these will not be generated, so in these situation
you have to generate the whole module.<p>
To see how to use the generated dot-file, please go to the <tt>Help</tt>
menu, and select the <tt>How to use the output</tt> item.
<p><hr><center><h1>The configuration widgets</h1></center>
TDG uses a lot of widgets to let you configure the different options. Some
of them are well known from other applications and include: check boxes,
radio buttons, pull-down menus, entries, text boxes (for multi-line text),
directory and file browsers. Others, however, are specifically designed for use
in TDG, and they will be described in the following.
<p><center><h2>The ExtEntry widget</h2></center>
The ExtEntry is a container, which repeats its elements, just like a
list-box repeat labels. A number of the elements in the ExtEntry may be
visible on the screen at a time. The elements in the ExtEntry may be any of
the widgets from TDG (ie. check boxes, pull-down menus and even other
ExtEntries.) One element in an ExtEntry is called a tuple.
In Figure 3, you can see an ExtEntry from the Tcsh module.<p>
<center>
<img width=600 height=105 src="./gx/pedersen/extentry1.jpg"><br>
Figure 3
</center><p>
This ExtEntry has three visible tuples, though only two of them contain
values (you can see, that the third one is grayed out). To add a new tuple
to the ExtEntry, you have to press the button in the lower right corner,
just below the scroll bar. If the ExtEntry contains more tuples than can be
shown in it, you may scroll to the other tuples with the scroll bar.<p>
If you press the left mouse button on one of the scissors, a menu
with four elements will be displayed. These elements are used to cut, copy
and paste tuples within the ExtEntry.<p>
If the tuples get very large, only one of them may be shown on the screen
at a time. An example of that is seen in figure 4.<p>
When the tuples contain many widgets, scrolling the ExtEntry becomes
slow. In these cases, the ExtEntry may have a quick index. In figure 4, you
can see the quick index at the top of the ExtEntry (it's the button labeled
Idx.) When this quick index is invoked, a pull-down menu is display with
the values of the element associated with the quick index. This makes it much
easier to scroll the ExtEntries.<p>
<table CELLSPACING=1 CELLPADDING=4 cols=2 width=100%>
<tr>
<td align=top>
<center><img width=310 height=272 src="./gx/pedersen/extentry2.jpg"><p>Figure 4</center>
<td align=top>
<center><img width=360 height=274 src="./gx/pedersen/prompt.jpg"><p>Figure 5</center>
</table>
<p><center><h2>The FillOut widget</h2></center>
Every shell has a configuration option called <tt>Prompt</tt>. This option
is some text, which will be printed, when the shell is ready to execute a
new command. In this text special tokens may be inserted, and when the
prompt is printed, these tokens will be replaced, with some information from
the shell. Eg. in Bash <tt>\w</tt> will be expanded to the current working
directory.<p>
In TDG, a special widget has been created called a <tt>FillOut</tt>, which
does configurations like the above. In Figure 5, you can see a FillOut
widget from the Bash module. At the top of the widget there is an entry,
where you can type ordinary text. Below it, the tokens are placed. If you
select one of the tokens, it is inserted in the entry at the point of the
cursor. Some of the tokens may even have some additional
configurations. Eg. the token <tt>Current working directory</tt> has two
possible options: <tt>Full directory</tt>, and <tt>only the last part</tt>. When tokens with
additional configurations are selected, a window will be displayed, where
these configurations can be done. If you wish to change such a configuration,
press the left mouse button on the token in the entry.
<p><center><h2>The Command widgets</h2></center>
TDG can be extended by the module programmer through the Command
widget. This makes it possible to configure specific options with widgets
they have developed themseves. At the moment three such widgets exist: The
directory/file browser, the color widget and the font widget.<p>
The widgets will appear as a button within TDG, and when the button is
pressed a new window will be displayed, where the actual configuration is done.
<p><hr><center><h1>Save, Export and Reload</h1></center>
When you have configured the different options in TDG, you may wish to
leave it, and come back later, and change some of the configurations. When
you leave TDG, you may save your changes, which you do from the
<tt>File</tt> menu.<p>
Next time you enter TDG, your saved file will be one of the the files you
will be offered as a start-up configuration.<p>
One important point you have to note is that this <tt>save file</tt> is an
internal dump of the state of TDG. This means that this file dependson
the version of TDG and the module. This means that if you wish to send a
given configuration to another person, this format is not appropriate. A
version independent format exists, which is called the <i>export
format</i>. To create such a file, you have to select <tt>Export</tt>
instead of <tt>Save</tt> in the <tt>File</tt> menu.<p>
Sometimes you may wish to restore the configuration on a single page, to its
value as it was before you started playing around with it, or you may wish
to merge another person's configuration with your own. This is done by selecting
<tt>Reload</tt> in the <tt>File</tt> menu. To tell TDG that you only want
to reload some of the pages, you have to select the <tt>Detail</tt> button
in the load window. This will bring up a window, where you can select which
configuration pages, you wish to reload. Here you can also tell it how you
want the pages to be reloaded. You have two possibilities:
<dl>
<dt> Overwrite
<dd> The pages you are loading, will totally overwrite the
contents of the file
<dt> Merge
<dd> Tuples in the ExtEntries will be appended to those which already
exist in the module. Other configurations will be ignored in the file.
</dl>
Here's another difference between the save-files and the export-files: You
cannot merge with save-files. This means that if you have a save-file,
which you wish to merge with, you first have to load it, export it, and
then you can merge with it.
<p><hr><center><h1>The End</h1></center>
Additional information
can be found on <a href="http://www.imada.ou.dk/~blackie/dotfile/">the home page
</a> for TDG.<p>
It's always a good idea to have a bookmark on this page, as work is
currently in progress on new modules.
<dl>
<dt> procmail
<dd> I have finished a module on procmail, a mail
filter, which can sort your incoming mail.<p>
<dt> firewall configuration (ipfwadm)
<dd> John D. Hardin (<a
href="mailto:jhardin@wolfenet.com">jhardin@wolfenet.com</a>) is
working on a module for configuring the fire walling and IP
Masquerading setup for standalone systems connected to the Internet via
dialup. He may, however, expand it to more general fire walling.
</dl>
If you have some spare time, I would very much like to encourage you to
develop a module for your favorite program. On the home page of TDG, there
is a link to a document, which describe how to create a module for TDG. <a
href="mailto:blackie@imada.ou.dk">Send me a letter</a>, and I will be happy
to help you get started with it.
<hr>
<address><a href="http://www.imada.ou.dk/~blackie/">Jesper Kj&aelig;r
Pedersen</a> &lt;blackie@imada.ou.dk&gt;</address>
<!-- hhmts start -->
Last modified: Wed Feb 5 15:59:35 1997
<!-- hhmts end -->
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1997, Jesper Pedersen <BR>
Published in Issue 17 of the Linux Gazette, May 1997</H5></center>
<!--===================================================================-->
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<!-- What is a Graphics Muse? -->
<FONT size=4><B>muse:</B></FONT>
<OL>
<LI><I>v;</I> to become absorbed in thought
<LI><I>n;</I> [ fr. Any of the nine sister goddesses of learning and the
arts in Greek Mythology ]: a source of inspiration
</OL>
<IMG SRC="../gx/hammel/w.gif" ALT="W" ALIGN="left"
HSPACE="0" VSPACE="0" WIDTH="36" HEIGHT="28">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.
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<FONT size=2>
[<A HREF="#mews">Graphics Mews</A>]
[<A HREF="#musings">Musings</A>]
[<A HREF="#resources">Resources</A>]
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<td>
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<IMG SRC="../gx/hammel/t.gif" ALT="T" ALIGN="left"
HSPACE="0" VSPACE="0" WIDTH="26" HEIGHT="28">his
column is dedicated to the use, creation, distribution, and dissussion of
computer graphics tools for Linux systems.
<BR clear=both>
&nbsp; &nbsp; &nbsp;
What a month. Actually, two months. Last month I was busily working
on putting together an entry for the IRTC using BMRT. At the same time
I was trying to teach myself enough about the RenderMan Interface
Specification to put together the second of three articles on BMRT.
I didn't succeed in the latter and ended up postponing the article
by one month. Because I did this
I was able to focus more on learning the interface and worry less
about writing. I think this strategy worked. The scene I rendered for this
months IRTC is the best I've ever done and I managed to gain enough
experience to write a meaningful article on the RenderMan Shading Langauge.
<BR clear=both>
&nbsp; &nbsp; &nbsp;
One of the reasons I enjoy doing this column is because it exposes me to
all sorts of people and software. The world of computer graphics for
Linux is constantly growing and the software constantly improves. I
hear about new products just about once or twice a week now and I hear
about updates to existing packages all the time. Its very difficult to
keep track of all the changes (and the fact that I haven't made any updates
to the Linux Graphics mini-Howto in some time reflects this) but I enjoy
the work.
<BR clear=both>
&nbsp; &nbsp; &nbsp;
Since things change so often I have found its never clear how many
announcements I'll have for any one month. Its gone from famine to
feast - with this month being the feast. Most of the announcements in
this months column are from April alone. I don't know what happened -
maybe all the bad weather around the globe kept people inside and busily
working and now that the suns out they're starting to let loose what
they've done. I only wish I had the time to examine everything, to play
with them all. But my employer would rather I finish my current project
first. Has something to do with keeping my salary, so they say.
<BR clear=both>
&nbsp; &nbsp; &nbsp;
In this months column I'll only be covering two related items. The
first is a case study on learning to use BMRT. When you submit an image in
the IRTC you are required to submit an ASCII text file describing your
image and, to some extent, how you created it. Some people don't put much
work into this. I just about wrote a book. Since the information I
provided covered more than just BMRT I thought it would be relavent to this
column.
<BR clear=both>
&nbsp; &nbsp; &nbsp;
The second item is the long awaited (well, I waited a long time to
finish it anyway) 2nd article on BMRT that covers the RenderMan Shading
Language. I think this article came out quite good. I've included quite a
few samples and some general explanations on what they do. I want to
say right up front that I couldn't have done this without lots of help from
BMRT's author, Larry Gritz at Pixar. He was a very willing teacher and
critic who offered many tips and ideas for my IRTC entry. Most of that
also ended up in this article. Many thanks, Larry.
<BR clear=both>
&nbsp; &nbsp; &nbsp;
I know I said I'd do an HF-Lab article this month too, but that IRTC
entry took more time than I expected. It was quite addicting, trying
to get things just right. I have started to review HF-Lab once again
and will make it my first priority for next months column. I've already
figured out how to use the output from HF-Lab to produce height fields with
BMRT. Its quite simple really. Anyway, I hope you enjoy this months
articles.
<BR clear=both>
&nbsp; &nbsp; &nbsp;
Note: I've been asked by a couple of readers about support for 3D
hardware support in the various X servers. I'm going to contact the
X Server vendors (Xi Graphics, MetroLink, The XFree Project)
as well as Brian Paul (the MesaGL author)
and see what they have to say. If you are connected with these folks
and have some insight I'd love to hear what you have to say. Please
<A HREF="mailto:mjhammel@csn.net">email me</A> if you know if such
support is forthcoming and I'll include it in an upcoming Graphics
Muse column.
<P>
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<BR clear=both>
&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.
<P>
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<H4>
Frame grabber device driver for the ImageNation Cortex I video
capture card - Version 1.1
</H4>
&nbsp;&nbsp;&nbsp;
This adapter is an 512 by 486 resolution 8bit gray
scale video capture card. The device can provide data in
pgm file format or raw image data.
<BR>FTP site:<BR>
<A HREF="ftp://sunsite.unc.edu/pub/Linux/apps/video/cortex.drv.1.1.tgz">
ftp://sunsite.unc.edu/pub/Linux/
<BR>&nbsp;&nbsp;&nbsp;
apps/video/cortex.drv.1.1.tgz</A>
<BR>Web Site:<BR>
<A HREF="http://www.cs.ubc.ca/spider/jennings/cortex.drv.1.1.tgz">
http://www.cs.ubc.ca/spider/
<BR>&nbsp;&nbsp;&nbsp;
jennings/cortex.drv.1.1.tgz</A>
</td>
<td bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
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<td bgcolor="#ffffff" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
WIDTH="0" HEIGHT="0"></td>
<td width="49%" valign=top>
<H4>
3DOM - a new 3D modeller project using OpenGL for Linux
</H4>
&nbsp; &nbsp; &nbsp;
3DOM is a 3D Modeler for Unix (using HP StarBase or OpenGL/Mesa)
that is free for
non-commercial use. Source code is available. Binaries for
Linux/Intel, SGI, Sparc Solaris and HP-UX are also availalbe.
<P>
It's not quite 'ready for prime-time', meaning there is
almost no documentation
and there is still a lot of work to do on the user interface.
<A HREF="http://www.cs.kuleuven.ac.be/cwis/research/graphics/3DOM/">
http://www.cs.kuleuven.ac.be/
<BR>&nbsp;&nbsp;&nbsp;cwis/research/graphics/3DOM/</A>
</td>
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<td colspan=4 bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
<tr>
<td colspan=4>
<H4>
Pixcon/Anitroll R1.04
</H4>
I found this in my /tmp directory while getting ready for this months
column. I couldn't find a reference to it in any other Muse columns so I
guess I must have just misplaced it while preparing for an earlier issue.
Hopefully, this isn't too out of date.
<BR clear=both>
&nbsp;&nbsp;&nbsp;
Pixcon & Anitroll is a freely available 3D
rendering and animation package, complete with source.
Pixcon is a 3D renderer that creates high quality images by using a
combination of 11 rendering primitives. Anitroll is a forward kinematic
heirarchical based animation system that has some support for some
non-kinematic based animation (such as flock of birds, and autonomous
cameras). These tools are based upon the Graph library which is full
of those neat rendering and animation algorithms that those 3D faqs
keep mentioning. It also implements
some rendering techniques that were presented at Siggraph 96 by Ken
Musgrave and was used to generate an animation for Siggraph '95.
<BR clear=both>
&nbsp;&nbsp;&nbsp;
New features since version 1.03:
<UL>
<LI>elimination of a memory leak w/ the polygon class
<LI>implemented a vector system for fast preview of frames
<LI>reorganize rendering process to support future parallel processing
<LI>30-60 % reduction in rendering time and memory usage
</UL>
The Pixcon & Anitroll home page is at:
<BR clear=both>
&nbsp;&nbsp;&nbsp;
<A HREF="http://www.radix.net/~dunbar/index.html">
http://www.radix.net/~dunbar/index.html</A>
<BR clear=both>
Comments can be emailed to
<A HREF="mailto:dunbar@saltmine.radix.net">dunbar@saltmine.radix.net</A>
Pixcon is available either through the above web site or at Sunsite.
It is currently under:
<A HREF="ftp://sunsite.unc.edu/pub/Linux/Incoming/pixcon104.tgz">
/pub/Linux/Incoming/pixcon104.tgz</A>
and will be moved to:
<A HREF="ftp://sunsite.unc.edu/pub/Linux/apps/graphics/pixcon104.tgz">
/pub/Linux/apps/graphics/pixcon104.tgz</A>
NOTE: there is a file pixcon1.04.tgz in those directories,
but it's corrupted. Be sure to get the correct files.
</td>
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<td colspan=4 bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
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<tr>
<td colspan=4>
<H4>
ELECTROGIG 3DGO
</H4>
&nbsp;&nbsp;&nbsp
ELECTROGIG
is a software company specialiced in
3D solid modeling, visualization and animation software.
The latest version of 3DGO (version 3.2), a modeling
animation and raytracing package, is now available for
the Intel Linux platform. A beta version is also available for the
MkLinux platform.
Take a look at the benchmarks for Linux
on the intel platform:
<A HREF="http://www.gig.nl/products/prodbench.html">
http://www.gig.nl/products/prodbench.html</A>.
<BR clear=both>
&nbsp;&nbsp;&nbsp
3DGO was originally developed for the SGI platform and
is available for the SGI, SUN and HP platforms.
<BR clear=both>
&nbsp;&nbsp;&nbsp
For more comprehensive information about 3DGO, check out the
WWW-site:
<A HREF="http://www.gig.nl/products/prodinfo.html">
http://www.gig.nl/products/prodinfo.html</A>.
<BR clear=both>
&nbsp;&nbsp;&nbsp
You can download a demo-version of 3DGO for linux, this version
has all functionality, except the save functions. Go to our
download area:
<A HREF="ftp://ftp.gig.nl/demo/">
ftp://ftp.gig.nl/demo/</A>.
Please Read the .txt files before downloading.
<P clear=both>
ELECTROGIG Technology
<BR clear=both>
<A HREF="mailto:info@gig.nl">
INFO: info@gig.nl</A>
</td>
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HSPACE="0" WIDTH="0" HEIGHT="0"></td>
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<td width="50%">
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<tr>
<td>
<H4>
EZWGL v1.2, the EZ widget and graphics library.
</H4>
&nbsp; &nbsp; &nbsp;
EZWGL is a C library written on top of Xlib. It has been developed on
a Linux system and has been tested on the following platforms:
SunOS 4.1.4, OSF1 V3.2 Alpha, IRIX 5.3 Linux 1.2 and Linux 2.0.23.
It should work on all Unices with X11R6.
This release is the first one that comes with a complete postscript
manual.
<P>
For more information, check out
<A HREF="http://www.ma.utexas.edu/~mzou/EZWGL">
http://www.ma.utexas.edu/~mzou/EZWGL</A>.
</td>
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<td colspan=4 bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
<tr>
<td>
<H4>
xfpovray v1.2b
</H4>
&nbsp;&nbsp;&nbsp;
A new release of xfpovray, the graphical interface to
POV-Ray, has been released by
<A HREF="mailto:mallozzir@cspar.uah.edu"> Robert S. Mallozzi</A>.
xfpovray v1.2b requires the XForms library
and supports most of the numerous options of POV-Ray. You can view
an image of the interface and get the source code from
<BR clear=both>&nbsp;&nbsp;&nbsp;
<A HREF="http://cspar.uah.edu/~mallozzir/">http://cspar.uah.edu/~mallozzir/</A>
<BR clear=both>
There is a link there to the XForms home page if you don't yet have this
library installed.
</td>
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<td bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
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<td bgcolor="#ffffff" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
WIDTH="0" HEIGHT="0"></td>
<td width="49%">
<H4>
libgr V2.0.12
</H4>
&nbsp; &nbsp; &nbsp;
A new version of libgr, version 2.0.12, is now available from
<A HREF="ftp://ftp.ctd.comsat.com:/pub/linux/ELF/libgr-2.0.12.tar.gz">
ftp.ctd.comsat.com:/
<BR>&nbsp;&nbsp;&nbsp;
pub/linux/ELF/libgr-2.0.12.tar.gz</A>.
<UL>
<LH>Changes to this release:
<LI> updated pbm, pgm, ppm, pnm from netpbm-94.
<LI> All the netpbm-94 apps are now included. They are NOT built or
installed by default, however. You must say make everything, make
install_everything.
<LI> Minor mods to compile with bash-2.0.
<LI> Minor mods to compile with glibc-2.
</UL>
<I>libgr</I> is a collection of graphics
libraries, which includes fbm, jpeg,
pbm, pgm, ppm, pnm, png, tiff, rle.
<P>
<I>libgr</I> will build shared libs on Linux-ELF and on HP/UX.
</td>
<tr>
<td colspan=4 bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
<tr>
<td colspan=4>
<H4>
EPSCAN - scanner driver for EPSON ES-1200C/GT-9000 scanners
</H4>
&nbsp; &nbsp; &nbsp;
EPSCAN is a scanner driver for EPSON ES-1200C/GT-9000 scanners. It
includes a driver and a nice Qt-based X frontend.
It allows previewing, and
selecting a region of an image to be scanned, as well as changing
scanner settings. It only supports scanners attached to a SCSI port,
not to the parallel port.
<P>
EPSCAN can be found at
<BR>
<A HREF="ftp://sunsite.unc.edu/pub/Linux/Incoming/epscan-0.1.tar.gz">
ftp://sunsite.unc.edu/pub/Linux/Incoming/epscan-0.1.tar.gz</A>.
<BR>RPM versions of the binary and source are available from
<A HREF="ftp://ftp.redhat.com/pub/Incoming/epscan-0.1-1.src.rpm">
ftp://ftp.redhat.com/pub/Incoming/epscan-0.1-1.src.rpm</A>
<A HREF="ftp://ftp.redhat.com/pub/Incoming/epscan-0.1-1.i386.rpm">
ftp://ftp.redhat.com/pub/Incoming/epscan-0.1-1.i386.rpm</A>.
<BR>They're intended destinations are
<A HREF="ftp://ftp.redhat.com/pub/contrib/epscan-0.1-1.src.rpm">
ftp://ftp.redhat.com/pub/contrib/epscan-0.1-1.src.rpm</A>
<A HREF="ftp://ftp.redhat.com/pub/contrib/epscan-0.1-1.i386.rpm">
ftp://ftp.redhat.com/pub/contrib/epscan-0.1-1.i386.rpm</A>.
and
<A HREF="ftp://sunsite.unc.edu/pub/Linux/apps/graphics/scanners/epscan-0.1.tar.gz">
ftp://sunsite.unc.edu/pub/Linux/apps/graphics/scanners/epscan-0.1.tar.gz</A>
<P>
The driver should work for any of the
ES-{300-800}C / GT-{1000-6500} models as well, but has not been
tested on these.
<UL>
<LH>Requirements:</LH>
<LI>Linux 2.x
<LI>XFree3.x
<LI>Qt library version >= 1.1
<LI>libtiff version >= 3.4
<LI>g++ version >= 2.7.2
</UL>
Author: Adam P. Jenkins
&lt<A HREF="mailto:ajenkins@cs.umass.edu">ajenkins@cs.umass.edu</A>&gt
</td>
<tr>
<td colspan=4 bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
<tr>
<td width="50%">
<H4>
Inlab-Scheme Release 4
</H4>
&nbsp; &nbsp; &nbsp;
Inlab-Scheme Release 4 is now available for Linux/386 (2.X kernel,
ELF binary) and FreeBSD.
<BR clear=b0th>
&nbsp; &nbsp; &nbsp;
Inlab-Scheme is an independent implementation of the algorithmic
language Scheme as defined by the R4RS and the IEEE Standard
1178. In addition to the language core Inlab-Scheme has support
for bitmap/greymap processing of several kinds. Inlab-Scheme can
be used as a general tool for image processing, OCR or specialized
optical object recognition.
<BR clear=b0th>
&nbsp; &nbsp; &nbsp;
Inlab-Scheme Release 4 reads and writes multipage tiff/G4, XBM and
PNG graphic file formats. Inlab-Scheme Release 4 has built in
converters for various patent image file formats (USAPat,
PATENTIMAGES and ESPACE).
<BR clear=b0th>
&nbsp; &nbsp; &nbsp;
Inlab-Scheme is distributed at
<A HREF="http://www.munich.net/inlab/scheme">
http://www.munich.net/inlab/scheme</A>,
where additional information about the current state of the project,
supported platforms, current license fees and more is available.
</td>
<td bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
<td bgcolor="#ffffff" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
WIDTH="0" HEIGHT="0"></td>
<td width="49%">
<H4>
The Linux Game SDK Project
</H4>
The new WWW page for the Linux Game SDK is at
<BR clear=b0th>
&nbsp; &nbsp;
<A HREF="http://www.ultranet.com/~bjhall/GSDK/">
http://www.ultranet.com/~bjhall/GSDK/</A>.
<BR clear=b0th>
&nbsp; &nbsp; &nbsp;
The Linux GSDK Project is a new project which aims to make
a consistent and easy to use set of libraries to ease game
developers (professional or not) to make first class games
under the Linux OS. The GSDK will provide libraries for 2D and
3D graphics, advanced sound, networked games and input devices.
It should also improve the development of multimedia applications for
Linux. See the Web site for more informations.
<BR clear=b0th>
&nbsp; &nbsp; &nbsp;
The GSDK mailing list has moved from linux-gsdk@endirect.qc.ca to
<A HREF="mailto:linux-gsdk@mail.wustl.edu">linux-gsdk@mail.wustl.edu</A>.
Additionnal lists have been created for the various teams.
</td>
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<td colspan=4 bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
<tr>
<td colspan=4>
<H4>
WebMagick Image Web Generator
</H4>
&nbsp;&nbsp;&nbsp
WebMagick is a package which supports making image collections available
on the Web. It recurses through directory trees, building HTML pages,
imagemap files, and client-side/server-side maps to allow the user to
navigate through collections of thumbnail images (somewhat similar to
xv's Visual Schnauzer) and select the image to view with a mouse click.
<BR clear=both>
&nbsp;&nbsp;&nbsp
WebMagick is based on the "PerlMagick" ImageMagick PERL extension rather
than external ImageMagick utilities (as its predecessor "Gifmap" is). This
alone is good for at least a 40% performance increase on small images.
WebMagick supports smart caching of thumbnails to speed montage generation
on average size images. After a first pass at "normal" speed, successive
passes (upon adding or deleting images) are 5X to 10X faster due to the
caching.
<BR clear=both>
&nbsp;&nbsp;&nbsp
WebMagick supports a very important new feature in its caching subsystem:
it can create and share a thumbnail cache with John Bradley's 'xv' program.
This means that if you tell 'xv' to do an update, WebMagick montages will
benefit and you can run WebMagick as a batch job to update xv's thumbnails
without having to wait for 'xv' to do its thumbnail reduction (and get a
browsable web besides!).
<BR clear=both>
&nbsp;&nbsp;&nbsp
WebMagick requires the ImageMagick (3.8.4 or later) and PerlMagick (1.0 or
later) packages as well as a recent version of PERL 5.
<table>
<tr>
<td> Primary-site:
<td>
<A HREF="http://www.cyberramp.net/~bfriesen/webmagick/dist/webmagick-1.17.tar.gz">
http://www.cyberramp.net/~bfriesen/webmagick/dist/webmagick-1.17.tar.gz</A>
<tr>
<td> Alternate-site:
<td>
<A HREF="ftp://ftp.wizards.dupont.com/pub/ImageMagick/perl/webmagick-1.17.tar.gz">
ftp.wizards.dupont.com/pub/ImageMagick/perl/webmagick-1.17.tar.gz</A>
<tr>
<td> Perl Language Home Page:
<td> <A HREF="http://www.perl.com/perl/index.html">
http://www.perl.com/perl/index.html</A>
<tr>
<td> ImageMagick:
<td> <A HREF="http://www.wizards.dupont.com/cristy/ImageMagick.html">
http://www.wizards.dupont.com/cristy/ImageMagick.html</A>
<tr>
<td> PerlMagick:
<td> <A HREF="http://www.wizards.dupont.com/cristy/www/perl.html">
http://www.wizards.dupont.com/cristy/www/perl.html</A>
<tr>
<td> Author:
<td> <A HREF="mailto:bfriesen@simple.dallas.tx.us">
Bob Friesenhahn (bfriesen@simple.dallas.tx.us)</A>
</table>
</td>
<tr>
<td colspan=4 bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
<tr>
<td width="50%">
<H4>
SIMLIB IG - Commercial library
</H4>
&nbsp;&nbsp;&nbsp
SIMLIB IG a C library which enables communication with Evans &
Sutherland graphics Supercomputers (so called image generators).
It enables the user to communicate with Evans & Sutherland image
generators (Liberty and ESIG Systems) using a very efficient raw
Ethernet protocol. There is no need for using opcodes, since
SIMLIB IG provides an API to the functionality of the image
generators.
<BR clear=both>
&nbsp;&nbsp;&nbsp
Documentation comes printed in English, and source code
examples are provided on the distribution media.
The software is also available for SGI and NT systems.
<P clear=both>
SIMLIB IG for Linux is $2500 (US)
<BR clear=both>
SIMLIB IG for all other OS is $5000 (US)
<P clear=both>
<A HREF="mailto:office@knienieder.co.at">
KNIENIEDER Simulationstechnik KG
(office@knienieder.co.at)</a>
<BR clear=both>
Technologiezentrum Innsbruck
<BR clear=both>
AUSTRIA/EUROPE
</td>
<td bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
<td bgcolor="#ffffff" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
WIDTH="0" HEIGHT="0"></td>
<td width="49%">
<H4>
mtekscan - Linux driver for MicroTek ScanMaker SCSI scanners
</H4>
mtekscan is a Linux driver for MicroTek
ScanMaker (and compatible) SCSI scanners. Originally developed for the
ScanMaker E6, it is (so far) known to also work with the ScanMaker
II/IIXE/IIHR/III/E3/35t models, as well as with the Adara ImageStar I,
Genius ColorPage-SP2 and Primax Deskscan Color.
<BR clear=both>
&nbsp;&nbsp;&nbsp;
The new version of mtekscan is v0.2. It's still in beta testing,
but all major options should work without problems. Besides some
small bugfixes and minor improvements, the new version contains a
couple of new features, most notably:
<UL>
<LI>3-pass scanning support
<LI>gamma correction
<LI>loadable gamma correction tables
<LI>better documentation
</UL>
mtekscan v0.2 is available as mtekscan-0.2.tar.gz from the
Fast Forward ftp-server:
<BR clear=both>&nbsp;&nbsp;&nbsp;
<A HREF="ftp://fb4-1112.uni-muenster.de/pub/ffwd/">
ftp://fb4-1112.uni-muenster.de/pub/ffwd/</A>
<BR clear=both>
or from sunsite:
<BR clear=both>&nbsp;&nbsp;&nbsp;
<A HREF="ftp://sunsite.unc.edu/pub/Linux/apps/graphics/scanners/">
ftp://sunsite.unc.edu/
<BR clear=both>&nbsp;&nbsp;
pub/Linux/apps/graphics/scanners/</A>
</td>
<tr>
<td colspan=4 bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
<tr>
<td colspan=4>
<H4>
PNG binaries for Netpbm tools now available
</H4>
Linux binaries for pnmtopng, pngtopnm, and gif2png are available at:
<A HREF="http://www.universe.digex.net/~dave/files/pngstuff.tgz">
http://www.universe.digex.net/~dave/files/pngstuff.tgz</A>
If you have trouble dowloading that, see
<A HREF="http://www.universe.digex.net/~dave/files/index.html">
http://www.universe.digex.net/~dave/files/index.html</A>
for helpful instructions.
<BR clear=both>
&nbsp;&nbsp;&nbsp
PNG is the image format that renders GIF obsolete.
For details on that, you can visit the PNG home page at:
<A HREF="http://www.wco.com/~png/">
http://www.wco.com/~png/</A>.
<BR clear=both>
&nbsp;&nbsp;&nbsp
The only shared libraries you need are libc and libm; all of the
others are linked statically.
The versions of libraries used to build the programs are those
that were publicly available as of 1997-04-06:
<UL>
<LI>pnmtopng-2.34
<LI>gif2png 0.6 (beta)
<LI>zlib-1.0.4 (statically linked)
<LI>libpng-0.90 (statically linked)
<LI>netpbm-1mar1994 (statically linked)
</UL>
</td>
<tr>
<td colspan=4 bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
<tr>
<td colspan=4>
<H4>
TN-Image Version 2.5.0
</H4>
TN-Image is:
<UL TYPE=square>
<LI> Scientific image analysis program for the X Window System.
<LI> Mouse & menu-based image editing and scientific analysis with
user-friendly user interface.
<LI>Freely distributable.
</UL>
It includes a 123-page manual, tutorials, and on-line help.
The Unix version is highly customizable with regard to fonts,
colors, etc.
<UL TYPE=square>
<LH> System requirements</LH>
<LI> Unix version requires X11R5 or higher and Motif 1.2 or higher.
Statically-linked version does not require Motif.
<LI> Binaries are provided for the Linux (x86), Solaris, Irix,
ConvexOS, and MS-DOS.
<LI> DOS version requires SVGA card and 4 MB of RAM; handles all
VESA screen modes including 1600x1200, as well as XGA and XGA-2
video cards.
</UL>
<UL TYPE=square>
<LH>Some features of TN-Image</LH>
<LI> Scanner interface for H/P SCSI scanners with preview scan and
interactive image scanning at 8, 10, 12, 24, 30, and 36 bits/pixel
(Not available in ConvexOS and MS-DOS versions).
<LI> Create, cut/paste, and add text labels in multiple fonts and graphic
elements such as circles, Bezier curves, freehand drawing, etc.
<LI> Handles up to 512 images of any depth simultaneously. Each image can
be in a separate window or in a single large window to facilitate
creation of composite images. Cut/paste works even if images are
of different depths or in different windows.
<LI> Prints to PCL or PostScript printer. CMY, CMYK, or RGB formats.
<LI> Import/export formats: PCX, IMG, TIF (both Macintosh and PC),
JPEG, BMP, GIF, TGA, IMG, Lumisys Xray scanner, and ASCII images, of
any depth from 1-32 bits per pixel, color or monochrome, raw binary
images, 3D images (such as PET scan and confocal images), and
user-definable image formats. Handles unusual image depths such
as 12- and 17-bit grayscale.
<LI> Interconversion of image formats.
<LI> Solid and gradient flood fill.
<LI> R, G, and B image planes can be manipulated separately.
<LI> Adjust color, intensity, contrast, and grayscale mapping. Grayscale
images deeper than 8 bits/pixel, such as medical grayscale images,
can be viewed with a sliding scale to enhance any particular intensity
region.
<LI> Rotate, resize, warp, flip, invert or remap colors; crop, paint,
spray paint, etc.
<LI> Convolution filters: sharpen, blur, edge enhancement, shadow
sharpening, background subtract, background flatten, and noise
filter.
<LI> Interactively create arbitrary colormaps or select from 10,000
pre-defined colormaps.
<LI> Macro language and macro editor. Macro programming guide is included.
<LI> Image algebra function allows multiple images to be subtracted or
otherwise transformed according to arbitrary user-defined equations.
<LI> RGB & intensity histograms.
<LI> 3D images can be viewed interactively as a movie, or each frame can
be manipulated separately.
<LI> Many advanced features
</UL>
Contact and archive information:
<table>
<tr>
<td>Contact:
</td>
<td>tjnelson@las1.ninds.nih.gov
</td>
<tr>
<td>Archive locations
</td>
<td>
<A HREF="ftp://sunsite.unc.edu:/apps/graphics/tnimage250.linux.tar.gz">
sunsite.unc.edu:/apps/graphics/tnimage250.linux.tar.gz</A>
<br>
<A HREF="ftp://sunsite.unc.edu:/apps/graphics/tnimage250.linux-static.tar.gz">
sunsite.unc.edu:/apps/graphics/tnimage250.linux-static.tar.gz</A>
<br> <A HREF="ftp://las1.ninds.nih.gov:/pub/unix/tnimage250.linux.tar.gz">
las1.ninds.nih.gov:/pub/unix/tnimage250.linux.tar.gz</A>
<br><A HREF="ftp://las1.ninds.nih.gov:/pub/unix/tnimage250.linux-static.tar.gz">
las1.ninds.nih.gov:/pub/unix/tnimage250.linux-static.tar.gz</A>
<BR><A HREF="ftp://las1.ninds.nih.gov:/pub/unix/tnimage250.solaris.tar.gz">
las1.ninds.nih.gov:/pub/unix/tnimage250.solaris.tar.gz</A>
<BR><A HREF="ftp://las1.ninds.nih.gov:/pub/unix/tnimage250.irix.tar.gz">
las1.ninds.nih.gov:/pub/unix/tnimage250.irix.tar.gz</A>
<br><A HREF="ftp://las1.ninds.nih.gov:/pub/unix/tnimage250.solaris.tar.gz">
las1.ninds.nih.gov:/pub/unix/tnimage250.solaris.tar.gz</A>
<br><A HREF="ftp://las1.ninds.nih.gov:/pub/dos/tnimg216.zip">
las1.ninds.nih.gov:/pub/dos/tnimg216.zip</A>
</td>
</table>
</td>
<tr>
<td colspan=4 bgcolor="#ffffff" cellpadding=1 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
VSPACE="5" HSPACE="10" WIDTH="1" HEIGHT="1"></td>
<tr>
<td colspan=4 bgcolor="#000000" cellpadding=1 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
<tr>
<td colspan=4 bgcolor="#ffffff" cellpadding=1 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
VSPACE="5" HSPACE="10" WIDTH="1" HEIGHT="1"></td>
<tr>
<td colspan=4>
<!--
-- Did You Know Section
-->
<H4>Did You Know?</H4>
&nbsp; &nbsp; &nbsp;
...that there is a converter available to turn POV-Ray heightfields
into RenderMan compliant RIB files for use with BMRT? Florian
Hars writes:
<BLOCKQUOTE>
I've worked on my code, now it uses libpgm and has all the necessary
vector routines included, it is on my page (with some comparisions of
rendering time and memory consumption):
<A HREF="http://www.math.uni-hamburg.de/home/hars/rman/height.html">
http://www.math.uni-hamburg.de/home/hars/rman/height.html</A>
</BLOCKQUOTE>
Florian also has some pages of general POV vs. RenderMan comparisons:
<A HREF="http://www.math.uni-hamburg.de/home/hars/rman/rm_vs_pov.html">
http://www.math.uni-hamburg.de/home/hars/rman/rm_vs_pov.html</A>
<P>
&nbsp; &nbsp; &nbsp;
...that there is a freely available RenderMan shader library from
Guido Quaroni? The library contains shaders from the <B>RenderMan
Companion</B>, Pixar, Larry Gritz and a number of other places.
You can find a link to it from the BMRT Web pages at
<A HREF="http://www.seas.gwu.edu/student/gritz/bmrt.html">
http://www.seas.gwu.edu/student/gritz/bmrt.html</A>.
<P>
&nbsp; &nbsp; &nbsp;
...that there is an FTP site at CalTech that contains a large
number of RenderMan shaders? The collection is similar to Guido
Quaroni's archive, except the FTP site includes sample RIB files
that use the shaders plus the rendered RIBs in both GIF and TIFF
formats. The site is located at
<A HREF="ftp://pete.cs.caltech.edu/pub/RMR/Shaders/">
ftp://pete.cs.caltech.edu/pub/RMR/Shaders/</A>.
<!--
-- Q and A Section
-->
<P><FONT size=3><B>Q and A</B></FONT>
<P>
<I>Q: Where can I get a copy of the netscape color cube for
use with Netpbm? How should it be used?
</I>
<P>A: The color cube can be found at the web site for
the text <B>Creating Killer Websites</B> at
<A HREF="http://www.killersites.com/images/color_cube_colors.gif">
http://www.killersites.com/images/color_cube_colors.gif</A>.
The cube can be used in the following manner:
<CENTER>
<FONT size=2>
<table>
<tr>
<td>% giftopnm color_cube_colors.gif" > color_cube.ppm
</td>
<tr>
<td>% tgatoppm image.tga | ppmquant -m color_cube.ppm -fs | \
<br>&nbsp;&nbsp;&nbsp;
ppmtogif -interlace -transparent rgb:ff/ff/ff > image.gif
</td>
</table>
</FONT>
</CENTER>
where ff/ff/ff is any set of Red, Green, and Blue values
to make transparent.
<P>
<I>Q: Where can I get models of the human figure?
</I>
<P>A:
Here are two addresses for human figure models. The first is 3DCafe's
official disclaimer and the second takes you straight to the human
figures. Please read the disclaimer first (although you may need
an asp capable browser, such as Netscape 3.x to do so):
<A HREF="http://www.3dcafe.com/meshes.htm">
http://www.3dcafe.com/meshes.htm</A>
<BR><A HREF="http://www.3dcafe.com/anatomy.htm">
http://www.3dcafe.com/anatomy.htm</A>
<P><FONT size=2>From the <I>IRTC-L</I> mailing list</FONT>
<P>
<I>Q: Is there a VRML 2.0 compliant browser available for Linux?
</I>
<P>A: Yes. Dimension X's Liquid Reality is a fully compliant
VRML 2.0 browser. The download web page says that there will
be support as a plug-in for Netscape 3.x soon. This is a
commercial product with a free trial version available for
download. See
<A HREF="http://www.dimensionx.com/products/lr/download/">
http://www.dimensionx.com/products/lr/download/</A> for more
details.
<P><FONT size=2>From a friendly reader, whose name I
absent mindedly discarded before recording it. My
apologies.</FONT>
<P>
<I>Q: Can anyone tell me how I would go about defining a height field
according to a specific set of data points?
My goal is to be able to take a topographic map, overlay it with a
rough grid, and use the latitude, longitude, and elevation markings
as points in a definable 3-D space to create a height field roughly
equal to real topography.
</I>
<P>A: The easiest way is probably to write a PGM file.
I wouldn't use longitude and latidude because the length of one degree
isn't fixed and it will give reasonable results only near the equator.
Use UTM coordinates or superimpose any arbitrary grid on your map
which represents approximate squares.
<PRE>
P2
# kilimajaro.pgm
15 10
59
10 15 18 20 21 22 23 23 21 20 19 18 17 16 15
11 15 19 22 27 30 30 30 29 28 25 20 19 18 17
13 15 19 21 28 38 36 40 40 35 30 24 20 19 18
15 16 18 20 29 39 37 44 59 44 38 30 22 19 18
15 16 18 20 28 30 30 40 50 46 51 48 28 20 19
15 15 16 17 18 19 20 24 30 35 37 37 30 20 19
15 15 14 15 16 17 18 19 22 29 30 29 27 20 19
15 15 14 13 15 16 15 17 18 20 22 20 20 20 18
15 14 13 11 12 12 12 13 14 15 17 15 15 15 14
14 11 10 9 9 10 10 10 9 10 13 12 11 11 11
</PRE>
Use it with scale <15,1.18,10> to get an to-scale image and with a
larger y-scale if you want to see something. The earth is incredibly
flat.
<P><FONT size=2>From Florian Hars via the
<I>IRTC-L</I> mailing list</FONT>
<P>
<A NAME="rib-csg"></A>
<I>Q: I've been fiddling with some simple CSG using BMRT and have run
into a problem. I'm trying to cut a square out of a plane that
was created from a simple bilinear patch. Whatever I use to define the
square (a box actually) comes out white instead of the background color
(black in this case). I dont know what I'm doing wrong and was
wondering if someone might take a peek at this for me.
</I>
<P>A:
There are several problems with your RIB file, as well as your use
of CSG. The two biggies are:
<P>You just can't do this:
<PRE>
ObjectBegin 2
SolidBegin "primitive"
TransformBegin
Translate -1 0 0
Rotate -90 0 1 0
Patch "bilinear" "P"
[ -1 -1 0 1 -1 0
-1 1 0 1 1 0 ]
TransformEnd
... etc.
ObjectEnd
</PRE>
&nbsp;&nbsp;&nbsp
Transformations just aren't allowed inside object definitions.
Remember that object instances inherit the entire graphics state
that's active when they are instanced -- including transformations.
So all primitives within the instanced object get the very same
transformation. If they're all bilinears like you have them, that
means that they will all end up on top of one another.
<BR clear=both>
&nbsp;&nbsp;&nbsp
For this reason and others, I urge everybody to <I>not use instanced
objects at all</I> for any RenderMan compliant renderer. They're quite
useless as described in the RenderMan 3.1 spec.
Yes, I know that <B>RenderMan Companion</B> has an example that does
exactly what I said is illegal. The example is wrong, and will not
work with either PRMan or BMRT.
<BR clear=both>
&nbsp;&nbsp;&nbsp
Solid (CSG) operations are meant only to operate on <I>solids</I>.
A solid is a boundary representation which divides space into three
distinct loci: (a) the boundary itself, which has finite surface area,
(b) a (possibly disconnected) region of finite volume (the "inside"),
and (c) a connected region of infinite volume (the "outside").
You can't subtract a box from a bilinear patch, since a bilinear patch
isn't a solid to begin with.
<BR clear=both>
&nbsp;&nbsp;&nbsp
If you want a flat surface with a square hole, there are two methods
that I'd recommend: (a) simply use several bilinears (4 to be exact)
for the surface, like this:
<PRE>
+-----------------------+
| #1 |
| |
+======+---------+======+
| | | |
| #2 | (hole) | #3 |
| | | |
+======+---------+======+
| #4 |
| |
+-----------------------+
</PRE>
Or, (B) if you really want to be fancy, use a single flat order 2
NURBS patch with an order 2 trim curve to cut out a hole.
<P><FONT size=2>
From Larry Gritz &lt;<A HREF="mailto:lg@pixar.com">lg@pixar.com</A>&gt;
</FONT>
</td>
<tr>
<td colspan=4 bgcolor="#ffffff" cellpadding=1 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
VSPACE="5" HSPACE="10" WIDTH="1" HEIGHT="1"></td>
<tr>
<td colspan=4 bgcolor="#000000" cellpadding=1 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
<tr>
<td colspan=4 bgcolor="#ffffff" cellpadding=1 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
VSPACE="5" HSPACE="10" WIDTH="1" HEIGHT="1"></td>
</table>
<P>
<A NAME="musings">
<table>
<tr>
<td>
<IMG SRC="../gx/hammel/musings.gif" ALT="Musings" ALIGN="left"
HSPACE="0" VSPACE="0" WIDTH="247" HEIGHT="52">
</td>
</table>
</A>
<BR clear=both>
<TABLE width=560>
<tr>
<td colspan=5 valign=top>
<H4>
Correcting for display gamma
</H4>
<IMG SRC="./gx/hammel/gamma-scale.jpg"
ALT="Gamma Correction Scale" ALIGN="right"
HSPACE="8" WIDTH="300" HEIGHT="832">
&nbsp;&nbsp;&nbsp;
This past 2 months I've been hard at work on an entry for this
round of the IRTC, the Internet Ray Tracing Competition. In
previous rounds I had submitted entries using POV-Ray, but for
this round I switched to BMRT, mostly so I could learn the RenderMan
API and how to write shaders using the RenderMan shading language.
This months main article is the second of a three part series on
BMRT. The BMRT package is written by Larry Gritz, and Larry was
gracious enough to offer some wonderful critiques and tips on
my image.
<BR>
&nbsp;&nbsp;&nbsp;
During out email correspondence, Larry noticed I had overlit my
scenes quite badly. While we tried to figure out what was causing
this (it turned out to be a misuse of some parameters to some
spotlights I was using) he asked if I had gamma corrected for my
display. Gamma correction is a big issue in computer graphics, one
that is often overlooked by novices. I'd heard and read quite a
bit about gamma correction but had never really attempted to determine
how to adjust the gamma for my display. Larry offered an explanation,
a quick way to test the gamma on my system, and a tip for
adjusting for gamma correction directly in the BMRT renderer, rendrib.
I thought this would be a great thing to share with my readers, so
here it is.
<BR>
&nbsp;&nbsp;&nbsp;
Rendrib produces linear pixels for its output -- i.e. a pixel with
value 200 represents twice as much light as a pixel of value 100.
Thus, it's expected that your display will be twice as bright
(photometrically, not necessarily perceptually) on a pixel of 200
than one of 100.
<BR>
&nbsp;&nbsp;&nbsp;
This sort of display only really happens if you correct for gamma,
the nonlinearity of your monitor. In order to check this,
take a look at the following chart. Display the chart as you'd
view any image. You'll notice that if you squint, the apparent
brightness of the left side will match some particular number on
the right. This is your gamma correction factor that must be
applied to the image to get linear response on your particular
monitor.
</td>
<tr>
<td valign=top width="54%">
<BR>
&nbsp;&nbsp;&nbsp;
If your display program uses Mesa (as rendrib's framebuffer display
does), you can set an environment variable, MESA_GAMMA, to this value
and it will transparently do the correction as it writes pixels to the
screen. Most display programs let you correct gamma when you view
an image, though I've had trouble getting xv to do it without messing
up the colors in a weird way.
<BR>
&nbsp;&nbsp;&nbsp;
Another alternative is to put the following line in your RIB file:
<PRE>
Exposure 1 &ltgamma&gt
</PRE>
</td>
<td bgcolor="#ffffff" cellpadding=1 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
WIDTH="0" HEIGHT="0"></td>
<td bgcolor="#000000" cellpadding=1 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
<td bgcolor="#ffffff" cellpadding=1 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
WIDTH="0" HEIGHT="0"></td>
<td valign=top width="40%" cellpadding=0 cellspacing=0>
<table>
<tr>
<td valign=top cellpadding=0 cellspacing=0>
<A NAME="next-column">
<U><B>More Musings...</B></U>
</A>
<BR clear=both>
<A HREF="more-musings.html#1">
My Entry in the March/April IRTC
</A> - a case study in learning to
use RenderMan and BMRT
<P clear=both>
<A HREF="bmrt-part2.html">
BMRT Part 2 - The RenderMan Shading Language
</A>
</td>
<tr>
<td bgcolor="#000000" cellpadding=1 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
WIDTH="1" HEIGHT="1"></td>
</table>
</td>
<tr>
<td colspan=5>
where gamma was what you measured with the chart.
This will cause rendrib to pre-correct the output pixels for the
gamma of your display.
I think it's important to gamma correct so that at least you're
viewing the images the way that rendrib "expects" them to appear.
It can't know about the nonlinearities of your CRT without you
telling it.
<BR>
&nbsp;&nbsp;&nbsp;
Larry has more on the gamma issue on his own pages. You can find
it at
<A HREF="http://www.seas.gwu.edu/student/gritz/gamma.html">
http://www.seas.gwu.edu/student/gritz/gamma.html</A>.
He also asked me to mention that he got this chart from
Greg Ward, but we didn't have any contact information for him.
Hopefully he doesn't mind our using it.
&nbsp;&nbsp;&nbsp;
Readers should note that the image displayed in this article may
not provide accurate information for adjusting gamma since your
browser may dither the colors in a way which changes what the
actual value should be. Also, this image is a JPEG version of
the original TIFF image Larry supplied. Its possible the conversion
also changed the image. If you're interested in trying this out you
should grab
<A HREF="./gx/hammel/gamma-scale.tif">the original TIFF image</A>
(300x832).
</td>
</table>
<P>
<A NAME="resources">
<table>
<tr>
<td>
<IMG SRC="../gx/hammel/resources.gif" ALT="Resources" ALIGN="left"
HSPACE="0" VSPACE="0" WIDTH="246" HEIGHT="57">
</td>
</table>
</A>
<BR clear=both>
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 clear=both>
<P>
<A HREF="http://www.csn.net/~mjhammel/linux-graphics-howto.html">
Linux Graphics mini-Howto
</A>
<BR>
<A HREF="http://www.csn.net/~mjhammel/povray/povray.html">
Unix Graphics Utilities
</A>
<BR>
<A HREF="http://www.digiserve.com/ar/linux-snd/">
Linux Multimedia Page
</A>
<P>
Some of the Mailing Lists and Newsgroups I keep an eye on and where I get alot
of the information in this column:
<P> <A HREF="http://www.XCF.Berkeley.EDU/~gimp/">
The Gimp User and Gimp Developer Mailing Lists</A>.
<BR> <A HREF="http://www.povvray.org/irtc">
The IRTC-L discussion list</A>
<BR> <A HREF="news:comp.graphics.rendering.raytracing">
comp.graphics.rendering.raytracing</A>
<BR> <A HREF="news:comp.graphics.rendering.renderman">
comp.graphics.rendering.renderman</A>
<BR> <A HREF="news:comp.os.linux.announce">
comp.os.linux.announce</A>
<br>
<P>
<A NAME="future">
<H2>Future Directions</H2>
</A>
Next month:
<UL>
<LI>HF-Lab - no really, I mean it this time.
<LI>Possibly a review of Image Alchemy
<LI>A preview of Gimp 1.0 (unless its already released, in which
case it won't be a preview)
<LI>If I can find the info, I'll report on the future of 3D hardware
support from Xi Graphics, Metro and The XFree Project.
<LI>and who knows what else.
</UL>
<BR>
<A HREF="mailto:mjhammel@csn.net">
Let me know what you'd like to hear about!</A>
<P>
<HR>
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1997, Michael J. Hammel<BR>
Published in Issue 17 of the Linux Gazette, May 1997</H5></center>
<!--===================================================================-->
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<BR clear=both>
<table>
<tr><td>
<UL>
<LI><A HREF="#1">My Entry in the March/April IRTC</A>
- a case study in learning to use RenderMan and BMRT
</UL></td>
</table>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
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<table width=100%>
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<FONT size=1>
&copy 1997 <A HREF="mailto:mjhammel@csn.net">Michael J. Hammel</A>
</FONT></td>
<tr>
<td bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
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</table>
<P>
<A NAME="1">
<H4>
My Entry in the March/April IRTC - a case study in learning to
use RenderMan and BMRT
</H4>
</A>
&nbsp; &nbsp; &nbsp;
One reason I took so long to get down to writing the Muse column this month
was that I was hard at work on an entry in the IRTC, the Internet Relay
Tracing Competition, which I help administer. I've been an active
participant in the IRTC since its restart back in May 1996 but have only
actually entered one competition. So this round had a special meaning for
me. I don't often have the time to work on entries unless something else
suffers. In this case, it was last months Muse column. To be honest,
however, I was also using this entry to learn more about RenderMan, BMRT
and in particular, the RenderMan Shading Language. Nothing is quite such a
a teacher as experience. And my entry in the IRTC was a wonderful teacher.
<BR>
&nbsp; &nbsp; &nbsp;
Below I've included the text file which accompanies my entry in the
IRTC. All entries must have this file. It describes the who/what/how and
so forth relating to an entry. I'll let the text file describe what I did,
who helped me do it, and some of the issues I encountered. I hope you find
this useful information.
<table>
<tr>
<td valign=top>
<table>
<tr>
<td valign=top> <FONT size=2> <B>EMAIL:</B></td> </FONT>
<td valign=top> <FONT size=2> mjhammel@csn.net </FONT></td>
<tr>
<td valign=top> <FONT size=2> <B>NAME:</B> </FONT></td>
<td valign=top> <FONT size=2> Michael J. Hammel </FONT></td>
<tr>
<td valign=top> <FONT size=2> <B>TOPIC:</B> </FONT></td>
<td valign=top> <FONT size=2> school </FONT></td>
<tr>
<td valign=top> <FONT size=2> <B>TITLE:</B> </FONT></td>
<td valign=top> <FONT size=2> Post Detention </FONT></td>
<tr>
<td valign=top> <FONT size=2> <B>RENDERER USED:</B> </FONT></td>
<td valign=top> <FONT size=2> BMRT </FONT></td>
<tr>
<td valign=top> <FONT size=2> <B>TOOLS USED:</B></FONT></td>
<td valign=top> <FONT size=2> Linux, AC3D, BMRT, Gimp 0.99.8,
wc2pov, xcalc, xv</FONT></td>
<tr>
<td valign=top> <FONT size=2> <B>RENDER TIME:</B></FONT></td>
<td valign=top> <FONT size=2> about 4 hours</FONT></td>
<tr>
<td valign=top> <FONT size=2> <B>HARDWARE USED: </B></FONT></td>
<td valign=top> <FONT size=2> Cyrix P166 (133Mhz)
based Linux system, 64M memory</FONT></td>
</table>
<td valign=top width=311>
<A HREF="./gx/hammel/mjhpd.jpg">
<IMG SRC="./gx/hammel/mjhpd.jpg" ALT="Post Detention - thumbnail" ALIGN="right"
HSPACE="10" WIDTH="291" HEIGHT="218" border=0>
<BR clear=both>
<CENTER>
Post Detention - Full size image is 800x600 / 102k
</CENTER>
</A>
</table>
<B>IMAGE DESCRIPTION:</B>
<BR>
&nbsp; &nbsp; &nbsp;
Pretty simplistic, really. Its a school room, just after detention has let
out. You can tell that detention has let out by the writing on the chalk
board and the time displayed by the clock on the wall. The sun is starting
to get low outside, which causes the types of shadows you can see on the
bookshelf. All the students who were in detention are required to read the
latest New York Times bestseller titled "Post Detention". Its written by
some author who is rumored to do 3D graphics on the side. You can see the
book on the desk in the lower right corner of the image.
<P>
<B>DESCRIPTION OF HOW THIS IMAGE WAS CREATED:</B>
<BR>
&nbsp; &nbsp; &nbsp;
I used this image to learn to use RenderMan and BMRT. I find I like these
tools a bit better than POV-Ray, mostly because I can write C code to
create models if I want (although I didn't for this particular scene) and
the shader language allows a bit more control than POV's. I still have
much to learn to make real use of these features, however.
<BR>
&nbsp; &nbsp; &nbsp;
I started with some canned models from 3DCafe: a chair, a couple of
bookcases, and some books. I had to convert the chair from 3DS to DXF so I
could then import it into AC3D. Once I had it in the modeler, I broke the
chair into two pieces - the arm and the rest of the chair. I did this so I
could texture them seperately (note that in the 3DS format these pieces may
have already been seperate, but after the conversion to DXF they were a
single entity). I also sized the chair to be a common unit size and
centered it on the origin. This unit size was used on all models so that
the real sizing and positioning could be done in the RIB file.
<BR>
&nbsp; &nbsp; &nbsp;
The book case only needed resizing but the books had to be broken into a
cover and "text pages". The latter are a single entity that were textured
with a matte finish. The covers were textured individually. All the books
are basically the same book sized differently and placed in the bookcase
from within AC3D. This provided relative positioning for the books in the
bookcase, after which any other translations would maintain that relative
positioning. Books on the chairs or floor were done similarly.
<BR>
&nbsp; &nbsp; &nbsp;
The walls are simple polygons or bilinear patches. The windowed wall
turned out to show problems in the way AC3D does polygons for RIB output.
I had to convert this wall from polygons to a set of bilinear patches (see
the May issue of the Graphics Muse for
<A HREF="gm.html#rib-csg">how to make a hole in a wall using bilinear
patches</A>)
in order for the texture to be applied evenly over all of
the patches. This problem also showed up when trying to apply texture maps
to the chalk board. It apparently has to do with vertex ordering. I had
to change the chalkboard to a bilinear patch too. I may have to write my
own models for anything that uses texture maps in the future instead of
using AC3D. To his credit, I haven't told Andy (AC3D's author) about this
yet and he's been very good about addressing any problems I've found in the
past.
<BR>
&nbsp; &nbsp; &nbsp;
An important aspect of this image is the tremendous help I got from Larry
Gritz, the author of BMRT. He offered some special shaders, although I
only used one of them (the one for the ceiling tiles). The biggest help
was very constructive criticism and tips for things too look for in my
code. For example, he pointed out that I was probably using the parameters
to spotlights incorrectly. I was, and it was causing my scene to be
<I>very</I>
overlit (spotlights use coneangle in radians, and I had specified them in
degrees). This one change made a dramatic improvement in the overall
image.
<BR>
&nbsp; &nbsp; &nbsp;
All the shaders used, except for the ceiling tiles and the papers on the
desks, are from the archive of shaders from Guido Quaroni. This archive
includes shaders from the RenderMan Companion by Steve Upstill, from
Texturing and Modeling by Ebert, Musgrave, et al, Larry Gritz, and various
other places. Its quite a useful resource for novices just getting started
with shaders and RenderMan. The papers on the desks are textured with a
shader I wrote that creates the horizonatl and vertical lines. It also
puts in 3 hole punches, but thats not obvious from the image. This shader
is the only one I included in the source [Ed. The IRTC allows the source
code for scenes to be uploaded along with the JPEG images and text file].
The chairs are textured with a
rusty metallic shader and a displacement shader for the dents.
Displacement shaders are cool because they actually move points on the
surface (unlike bump maps which just change the normals for those points).
The arm surfaces are textured with a wood shader that I made a minor change
to (to allow better control of the direction of the wood grain) and a
displacement shader that caused the bumpiness, scratches, and chips in the
wood. This latter item could have been better, but I was running out of
time.
<BR>
&nbsp; &nbsp; &nbsp;
The chalkboard is an image map created in the 0.99.8 developers release of
the Gimp. This is a <I>very</I> cool tool for Linux and Unix platforms, very
similar to Photoshop (but apparently better, according to people who've
used both - I've never used Photoshop myself).
<BR>
&nbsp; &nbsp; &nbsp;
The image out the window is an image map on a simple plane angled away from
the window. The window panes are dented using a displacement map. We had
windows with bumps in them in High School and thats the effect I was going
for here. Its pretty close and as an added benefit it prevents the image
outside the window from being too washed out.
<BR>
&nbsp; &nbsp; &nbsp;
The globe on the book shelf is one of those ones that is suspended by
magnets. The globe has a displacement map on it as well, which is why,
if you look real close, the lighting on it is not smooth where it moves
into shadow. The globe and its base were completely modeled in AC3D. It
was quick and very easy to do. All the items on the booksshelf by the
window are in a single model file, but exported as individual objects so
they could be shaded properly. The same is true for the bookcase under the
clock.
<BR>
&nbsp; &nbsp; &nbsp;
It was fun. This is certainly the best 3D image I've done to date. Its
also the first one of something recognizable (as opposed to space ships and
planets no one has ever really seen).
<BR>
&nbsp; &nbsp; &nbsp;
<B>NOTE:</B>
One thing I forgot to mention in my original text file for my entry is that
I had to edit all the exported RIB files that I created with AC3D to remove
the bits of RIB that made each file an independently renderable file. By
default AC3D generates a complete scene, one that can be passed to rendrib
(the BMRT renderer) directly to render a scene. But what I needed was for
the files generated to be only partially complete scenes, without the
camera or lighting and so forth. In this way I could use these files in
RIB ReadArchive statements, similar to #include files for POV. Considering
the number of objects I exported with AC3D, that turned out to be quite a
bit of hand editing. I sent email to Andy Colebourne, the author of AC3D,
and he's looking into making it possible to output partial RIBs for use as
ReadArchive include files.
<P>
<table width=100%>
<tr>
<td colspan=4 bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
</table>
<table width=100%>
<tr>
<td align=right>
<FONT size=1>
&copy 1997 by <A HREF="mailto:mjhammel@csn.net">Michael J. Hammel</A>
</FONT>
</table>
<TITLE>
Graphics Muse
</TITLE>
</HEAD>
<BODY text="#000000" bgcolor="#ffffff"
vlink="#fa3333" alink="#33CC33" link="#0000FA">
<!-- =============================================================
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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">
<table>
<tr>
<td>
<H2>More...</H2>
<BR clear=both>
<IMG SRC="../gx/hammel/musings.gif" ALT="Musings" ALIGN="left"
HSPACE="0" VSPACE="0" WIDTH="247" HEIGHT="52">
</td>
</table>
</A>
<BR clear=both>
<table>
<tr><td>
<H3>BMRT</H3>
<td rowspan=2 bgcolor=#000000>
<IMG SRC="./gx/hammel/plank.jpg" ALT="Gritz Sample 1" ALIGN="middle"
HSPACE="0" VSPACE="0" WIDTH="305" HEIGHT="227">
<BR clear=both>
<CENTER>
<FONT color=#ffffff size=1>Image courtesy of Larry Gritz</FONT>
</CENTER>
<tr><td>
<OL>
<LH><B> Part II:
Renderman Shaders
<B></LH>
<LI><A HREF="#review">A quick review</A>
<LI><A HREF="#what">What is a shader?</A>
<LI><A HREF="#compiling">Compiling shaders</A>
<LI><A HREF="#types">Types of shaders</A>
<LI><A HREF="#syntax">Shader language syntax</A>
<OL TYPE=a>
<LI><A HREF="#names">Shader names</A>
<LI><A HREF="#variables">Variables and scope</A>
<LI><A HREF="#data-types">Data types and expressions</A>
<LI><A HREF="#functions">Functions</A>
<LI><A HREF="#statements">Statements</A>
<LI><A HREF="#coordinates">Coordinate systems</A>
</OL>
<LI><A HREF="#format">Format of a shader file</A>
<LI><A HREF="#texture-maps">A word about texture maps</A>
<LI><A HREF="#examples">Working examples</A>
<OL TYPE=a>
<LI><A HREF="#examples-1">Colored Mesh pattern</A>
<LI><A HREF="#examples-2">Adding opacity - a wireframe shader</A>
<LI><A HREF="#examples-3">A simple paper shader</A>
<LI><A HREF="#examples-4">A texture mapped chalk board</A>
<LI><A HREF="#examples-5">Displacement map example</A>
</OL>
</OL></td>
</table>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
VSPACE="5" WIDTH="1" HEIGHT="1">
<BR clear=both>
<table width=100%>
<tr>
<td width="100%" align=right>
<FONT size=1>
&copy 1996 <A HREF="mailto:mjhammel@csn.net">Michael J. Hammel</A>
</FONT></td>
<tr>
<td bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
</table>
<P>
<A NAME="review"></A>
<H2>1. A quick review</H2>
&nbsp; &nbsp; &nbsp;
Before we get started on shaders, lets take a quick look back at RIB files.
RIB files are ASCII text files which describe a 3D scene to a RenderMan
compliant renderer such as BMRT. A RIB file contains descriptions of
objects - their size, position in 3D space, the lights that illuminate them
and so forth. Objects have surfaces that can be colored and textured,
allowing for reflectivity, opacity (or conversely, transparency),
bumpiness, and various other aspects.
<BR>
&nbsp; &nbsp; &nbsp;
An object is instanced inside AttributeBegin/AttributeEnd requests (or
procedures in the C binding). This instancing causes the current graphics
state to be saved so that any changes made to the graphics state (via the
coloring and texturing of the object instance) inside the
AttributeBegin/AttributeEnd request will not affect future objects. The
current graphics state can be modified, and objects colored and textured,
with special procedures called <I>shaders</I>.
<BR>
&nbsp; &nbsp; &nbsp;
<B>Note:</B>
Keep in mind that this is not a full fledged tutorial and I won't be
covering every aspect of shaders use and design. Detailed information can
be found in the texts listed in the bibliography at the end of this
article.
<P>
<A NAME="what"></A>
<H2>2. What is a shader?</H2>
&nbsp; &nbsp; &nbsp;
In the past, I've often used the terms <I>shading</I> and <I>texturing</I>
interchangeably. Darwyn Peachy, in his
<FONT COLOR="#335533">
<U><I>Building Procedural Textures</I></U>
</FONT>
chapter in the text <B>Texturing and Modeling: A Procedural Approach</B>,
says that these two concepts are actually separate processes:
<BLOCKQUOTE>
Shading is the process of calculating the color of a pixel
from user-specified surface properties and the shading model.
Texturing is a method of varying the surface properties from
point to point in order to give the appearance of surface
detail that is not actually present in the geometry of the
surface.
[<A HREF="#ref1">1</A>]
</BLOCKQUOTE>
A shader is a procedure called by the renderer to apply colors and textures
to an object. This can include the surface of objects like block or spheres,
the internal space of a solid object, or even the space between objects
(the atmosphere). Although based on Peachy's description would imply that
shaders only affect the coloring of surfaces (or atmosphere, etc), shaders
handle both shading and texturing in the RenderMan environment.
<P>
<A NAME="compiling"></A>
<H2>3. Compiling shaders</H2>
&nbsp; &nbsp; &nbsp;
RIB files use filenames with a suffix of ".rib". Similarly, shader files
use the suffix ".sl" for the shader source code. Unlike RIB files, however,
shader files cannot be used by the renderer directly in their source
format. They must be compiled by a shader compiler. In the BMRT package
the shader compiler is called <I>slc</I>.
<BR>
&nbsp; &nbsp; &nbsp;
Compiling shaders is fairly straightforward - simply use the slc program
and provide the name of the shader source file. For example, if you have a
shader source file named myshader.sl you would compile it with the
following command:
&nbsp;&nbsp;&nbsp;
<CODE>
slc myshader.sl
</CODE>
<BR>
You must provide the ".sl" suffix - the shader source file cannot be
specified using the base portion of the filename alone.
When the compiler has finished it will have created the compiled shader in
a file named myshader.so
in the current directory. A quick examination of
this file shows it to be an ASCII text file as well, but the format is
specific for the renderer in order for it to implement its graphics state
stack.
Note: the filename extension of ".so" used by BMRT (which is different
than the one used by PRMan) does not signify a binary object file, like
shared library object files. The file is an ASCII text file. Larry says
he's considering changing to a different extension in the future to avoid
confusion with shared object files.
<BR>
&nbsp; &nbsp; &nbsp;
Note that in the RIB file (or similarly when using the C binding)
the call to the shader procedure is done in the following manner:
<BR>
<PRE>
AttributeBegin
Color [0.9 0.6 0.6]
Surface "myshader"
ReadArchive "object.rib"
AttributeEnd
</PRE>
This example uses a <I>surface</I> shader (we'll talk about shader types in a
moment). The name in double quotes is the name of the shader procedure
which is not necessarily the name of the shader source file.
Since shaders are procedures they
have procedure names. In the above example the procedure name is
<I>myshader</I>. This happens to the be same as the base portion (without
the suffix) of the shader source filename. The shader compiler doesn't
concern itself with the name of the source file, however, other than to
know which file to compile. The output filename used for the .so file is
the name of the procedure. So if you name your procedure differently than
the source file you'll get a differently named compiled .so file. Although
this isn't necessarily bad, it does make it a little hard to keep track of
your shaders. In any case, the name of the procedure is the name used in
the RIB (or C binding) when calling the shader. In the above example,
"myshader" is the name of the procedure, not the name of the source file.
<P>
<A NAME="types"></A>
<H2>4. Types of shaders</H2>
&nbsp; &nbsp; &nbsp;
According to the <B>RenderMan Companion</B> [<A HREF="#ref2">2</A>]
<BLOCKQUOTE>
The RenderMan Interface specifies six types of shaders, distinguished
by the inputs they use and the kinds of output they produce.
</BLOCKQUOTE>
The text then goes on to describe the following shader types:
<OL>
<LI>Light source shaders
<LI>Surface shaders
<LI>Volume shaders
<LI>Displacement shaders
<LI>Transformation shaders
<LI>Imager shaders
</OL>
Most of these can only have one instance of the shader type in the graphics
state at any one time. For example, there can only be one surface shader
in use for any object or objects at a time. The exception to this are
light shaders, which may have many instances at any one time, some of which
may not be actually turned on for some objects.
<P>
<B><FONT COLOR="#335533">
Light Source Shaders
</FONT></B>
<BR>
&nbsp; &nbsp; &nbsp;
Light sources in the RenderMan Shading Language are provided a position and
direction and return the color of the light originating from that light and
striking the current surface point. The RenderMan specification provides
for a set of default light shaders that are very useful and probably cover
the most common lighting configurations an average user might encounter.
These default shaders include ambient light (the same amount of light
thrown in all directions), distant lights (such as the Sun), point lights,
spot lights, and area lights. All light sources have an intensity that
defines how bright the light shines. Lights can be made to cast shadows or not
cast shadows. The more lights that cast shadows you have in a scene the
longer it is likely to take to render the final image. During scene design
and testing its often advantagous to keep shadows turned off for most lights.
When the scene is ready for its final rendering turn the shadows back on.
<BR>
&nbsp; &nbsp; &nbsp;
Ambient light can be used to brighten up a generally dark image but the
effect is "fake" and can cause an image to be washed out, losing its
realism. Ambient light should be kept small for any scene, say with an
intensity of no more than 0.03. Distant lights provide a light that shines
in one direction with all rays being parallel. The Sun is the most common
example of a distant light source. Stars are also considered distant
lights. If a scene is to be lit by sunlight it is often considered a good
idea to have distant lights be the only lights to cast shadows. Distant
lights do not have position, only direction.
<BR>
&nbsp; &nbsp; &nbsp;
Spot lights are the familiar lights which sit at a particular location in
space and shine in one generalized direction covering an area specified by
a cone whose tip is the spot light. A spot lights intensity falls off
exponentially with the angle from the centerline of the cone. The angle is
specified in <I>radians</I>, not degress as with POV-Ray. Specifying the
angle in degrees can have the effect of severly over lighting the area
covered by the spot light. Point lights also fall off in intensity, but do
so with distance from the lights location. A point light shines in all
directions at once so does not contain direction but does have position.
<BR>
&nbsp; &nbsp; &nbsp;
Area lights are series of point lights that take on the shape of an object
to which they are attached. In this way a the harshness of the shadows
cast by a point light can be lessened by creating a larger surface of
emitted light. I was not able to learn much about area lights so can't
really go into detail on how to use them here.
<BR>
&nbsp; &nbsp; &nbsp;
Most light source shaders use one of
two illumination functions: illuminate() and solar(). Both provides ways
of integrating light sources on a surface over a finite cone. illuminate()
allows for the specification of position for the light source, while
solar() is used for light sources that are considered very distant, like
the Sun or stars. I consider the writing of light source shaders to be a
bit of an advanced topic since the use of the default light source shaders
should be sufficient for the novice user to which this article is aimed.
Readers should consult <B>The RenderMan Companion</B> and <B>The RenderMan
Specification</B> for details on the use of the default shaders.
<P>
<B><FONT COLOR="#335533">
Surface Shaders
</FONT></B>
<BR>
&nbsp; &nbsp; &nbsp;
Surface shaders are one of the two types of shaders novice users will make
use of most often (the other is displacement shaders). Surface shaders are
used to determine the color of light reflected by a given surface point
in a particular direction. Surface shaders are used to create wood
grains or the colors of an eyeball. They also define the opacity of a
surface, ie the amount of light that can pass through a point (the points
transparency). A point that is totally opaque allows no light to pass
through it, while a point that is completely transparent reflects no light.
<BR>
&nbsp; &nbsp; &nbsp;
The majority of the examples which follow will cover surface shaders. One
will be a displacement shader.
<P>
<B><FONT COLOR="#335533">
Volume Shaders
</FONT></B>
<BR>
&nbsp; &nbsp; &nbsp;
A volume shader affects light traveling to towards the camera as it passes
though and around objects in a scene. Interior volume shaders determine
the effect on the light as it passes through an object. Exterior volume
shaders affect the light in the "empty space" around an object.
Atmospheric shaders handle the space between objects. Exterior
and interior volume
shaders differ from atmospheric shaders in that the latter operate on all
rays originating from the camera (remember that ray tracing traces the
lights ray in reverse from nature - from camera to light source).
Exterior and interior shaders work only on secondary rays, those rays
spawned by the <I>trace()</I> function in shaders.
Atmospheric shaders are used
for things like fog and mist. Volume shaders are a slightly more advanced
topic which I'll try to cover in a future article.
<P>
<B><FONT COLOR="#335533">
Displacement Shaders
</FONT></B>
<BR>
&nbsp; &nbsp; &nbsp;
The texture of an object can vary in many ways, from very smooth to very
bumpy, from smooth bumps to jagged edges. With ordinary surface shaders a
texture can be simulated with the use of a <I>bump map</I>. Bump maps
perturb the normal of a point on the surface of an object so that the point
appears to be raised, lowered, or otherwised moved from its real location.
A bump map describes the variations in a surfaces orientation.
Unfortunately, this is only a trick and the surface point is not really
moved. For some surfaces this trick works well when viewed from the proper
angle. But when seen edge on the surface variations disapper - the edge is
smooth. A common example is an orange. With a bump map applied the orange
appears to be pitted over its surface. The edge of the sphere, however, is
smooth and the pitting effect is lost. This is where displacement shaders
come in.
<BR>
&nbsp; &nbsp; &nbsp;
In <B>The RenderMan Interface Specification</B>[<A HREF="#ref3">3</A>]
it says
<BLOCKQUOTE>
The displacement shader environment is very similar to a surface shader,
except that it only has access to the geometric surface parameters.
[A displacement shader] computes a new P [point] and/or a new N
[normal for that point].
</BLOCKQUOTE>
A displacement shader operates across a surface, modifying the physical
location of each point. These modifications are generally minor and of a
type that would be much more difficult (and computationally expensive) to
specify individually. It might be difficult to appreciate this feature
until you've seen what it can do.
Plate 9 in [<A HREF="#ref4">4</A>] shows an ordinary cylinder modified with
the <I>threads()</I> displacement shader to create the threads on the base
of a lightbulb. <B>Figures 1-3</B> shows a similar (but less sophisticated)
example.
Without the use of the displacement shader, each thread
would have to be made with one ore more individual objects. Even if the
computational expense for the added objects were small, the effort required
to model these objects correctly would still be significant. Displacement
shaders offer procedural control over the shape of an object.
<P>
<table>
<tr>
<td bgcolor=#000000 align=center valign=top width=33%>
<IMG SRC="./gx/hammel/cylinder.jpg" ALT="Ordinary cylinder" ALIGN="middle"
HSPACE="0" WIDTH="148" HEIGHT="209">
<td bgcolor=#000000 align=center valign=top width=33%>
<IMG SRC="./gx/hammel/cylnorms.jpg"
ALT="Ordinary cylinder with Normals modified" ALIGN="middle"
HSPACE="0" WIDTH="148" HEIGHT="209">
<td bgcolor=#000000 align=center valign=top width=33%>
<IMG SRC="./gx/hammel/cyldisp.jpg"
ALT="Cylinder with true displacments" ALIGN="middle"
HSPACE="0" WIDTH="151" HEIGHT="209">
<tr>
<td align=center bgcolor=#AAAAAA>
<FONT color=#ffffff>
<A HREF="./source/cylinder.rib">An ordinary cylinder</A>
</FONT>
<td align=center bgcolor=#AAAAAA>
<FONT color=#ffffff>
<CENTER>
<A HREF="./source/cylnorms.rib">Same cylinder with modified normals</A>
</CENTER>
<BR>
Note that in this case the renderer attributes have not been
turned on. The edges of the cylinder are flat, despite the
apparent non-flat surface.
</FONT>
<td align=center bgcolor=#AAAAAA>
<FONT color=#ffffff>
<A HREF="./source/cyldisp.rib">Same cylinder with true displacements</A>
<BR>
In this image the renderer attributes have been turned on. The
edges of the cylinder reflect the new shape of the cylinder.
</FONT>
<tr>
<td align=center >
<B>Figure 1</B>
<td align=center >
<B>Figure 2</B>
<td align=center >
<B>Figure 3</B>
</table>
<BR>
&nbsp; &nbsp; &nbsp;
An important point to remember when using displacement shaders with
BMRT is that, by default, displacements are not turned on. Even if
a displacement shader is called the points on the surface only have
their normals modified by the shader. In order to do the "true
displacement", two renderer attribute options must be set:
<PRE>
Attribute "render" "truedisplacement" 1
Attribute "displacementbound" "coordinatesystem"
"object" "sphere" 2
</PRE>
The first of these turns on the true displacement attribute so that
displacement shaders actually modify the position of a point on the
surface. The second specifies how much the bounding box around the
object should grow in order to enclose the modified points.
How this works is that the attribute tells the renderer how much the
bounding box is likely to grow <I>in object space</I>. The renderer can't
no before hand how much a shader might modify a surface, so this statement
provides a maximum to help the renderer with bounding boxes around
displacement mapped objects. Remember that bounding boxes are used help
speed up ray-object hit tests by the renderer. Note that you can compute
the possible change caused by the displacement in some other space, such as
world or camera. Use whatever is convenient. The "sphere" tag lets the
renderer know that the bounding box will grow in all directions evenly.
Currently BMRT only supports growth in this manner, so no other values
should be used here.
<P>
<B><FONT COLOR="#335533">
Transformation and Imager Shaders
</FONT></B>
<BR>
&nbsp; &nbsp; &nbsp;
BMRT doesn't support Transformation Shaders (neither does Pixar's PRMan
apparently). Apparently transformation shaders are supposed to operate on
geometric coordinates to apply "non-linear geometric transformations".
According to [<A HREF="#ref5">5</A>]
<BLOCKQUOTE>
The purpose of a transformation shader is to modify a coordinate system.
</BLOCKQUOTE>
It is used to deform the geometry of a scene without respect to any
particular surface. This differs from a displacement shader because the
displacement shader operates on a point-by-point basis for a given surface.
Transformation shaders modify the current transform, which means they
can affect all the objects in a scene.
<BR>
&nbsp; &nbsp; &nbsp;
Imager shaders appear to operate on the colors of output pixels which to me
means the shader allows for color correction or other manipulation after a
pixels color has been computed but prior to the final pixel output to file
or display. This seems simple enough to understand, but why you'd use them
I'm not quite sure. Larry says that BMRT supports Imager shaders but PRMan
does not. However, he suggests the functionality provided is probably
better suited to post-processing tools, such as XV, ImageMagick or the Gimp.
<P>
<A NAME="syntax"></A>
<H2>5. Shader language syntax</H2>
&nbsp; &nbsp; &nbsp;
So what does a shader file look like? They are very similar in format to a
C procedure, with a few important differences. The following is a very
simplistic surface shader:
<PRE>
surface matte (
float Ka = 1;
float Kd = 1;
)
{
point Nf;
/*
* Calculate the normal which is facing the
* direction that points towards the camera.
*/
Nf = faceforward (normalize(N),I);
Oi = Os;
Ci = Os * Cs * (Ka * ambient() + Kd * diffuse(Nf));
}
</PRE>
This is the matte surface shader provided in the BMRT distribution. The
matte surface shader happens to be one of a number of required shaders that
<B>The RenderMan Interface Specification</B> says a RenderMan compliant
renderer must provide.
<P>
<A NAME="names"></A>
<B><FONT COLOR="#335533">
Shader procedure names
</FONT></B>
<BR>
&nbsp; &nbsp; &nbsp;
The first thing to notice is the procedure type and name. In this case the
shader is a surface shader and its name is "matte". When this code is
compiled by slc it will produce a shader called "matte" in a file called
"matte.so". Procedure names can be any name that is not a reserved RIB
statement. Procedure names may contain letters, numbers and underscores.
They may not contain spaces.
<P>
<A NAME="variables"></A>
<B><FONT COLOR="#335533">
Variables and scope
</FONT></B>
<BR>
&nbsp; &nbsp; &nbsp;
There are a number of different kinds of variables that are used with
shaders: Instance variables, global variables, and local variables.
Instance variables are the variables used as parameters to the shader.
When calling a shader these variables are declared (if they have not
already been declared) and assigned a value to be used for that instance of
the shader. For example, the matte shader provides two parameters that can
have appropriate values specified when the shader is instanced within the
RIB file. Lets say we have a sphere for which we will shade using the
matte shader. We would specify the instance variables like so:
<PRE>
AttributeBegin
Declare "Kd" "float"
Declare "Ka" "float"
Surface "matte" "Kd" 0.5 "Ka" 0.5
Sphere 1 -.5 .5 360
AttributeEnd
</PRE>
The values specified for Kd and Ks are the instance variables and the
renderer will use these values for this instance of the shader. Instance
variables are generally known only to the shader upon the initial call for
the current instance.
<BR>
&nbsp; &nbsp; &nbsp;
Local variables are defined within the shader itself and as such are only
known within the shader. In the example matte shader, the variable Nf is a
point variable as has meaning and value only within the scope of the shader
itself. Other shaders will not have access to the values Nf holds.
Local variables are used to hold temporary values required to compute the
values passed back to the renderer. These return values are passed back as
global variables.
<BR>
&nbsp; &nbsp; &nbsp;
Global variables have a special place in the RenderMan environment. The
only way a shader can pass values back to the renderer is through global
variables. Some of the global variables that a shader can manipulate are
the surface color (Cs), surface opacity (Os), the normal vector for the
current point (N) and the incident ray opacity
(Oi). Setting these values within the shader affects how the renderer
colors surface points for the object which is being shaded. The complete
list of global variables that a particular shader type can read or modify
is listed in tables in the <B>RenderMan Interface Specification</B>
[<A HREF="#ref6">6</A>].
Global variables are global in the sense that they pass values between the
shader and the renderer for the current surface point, but they cannot be
used to pass values from one objects shader to another.
<P>
<A NAME="data-types"></A>
<B><FONT COLOR="#335533">
Data types and expressions
</FONT></B>
<BR>
&nbsp; &nbsp; &nbsp;
Shaders have access to only 4 data types: one scalar type, two vector
types, and a string type. A string can be defined and used by a shader, but
it cannot be modified. So an instance variable that passes in a string
value cannot be modified by the shader, nor can a local string variable be
modified once it has been defined.
<BR>
&nbsp; &nbsp; &nbsp;
The scaler type used by shaders is called a <I>float</I> type. Shaders must use
float variables even for integer calculations. The </I>point</I> type is a
a 3 element array of float values which describe a point in some space.
By default the point is in <I>world space</I> in BMRT (PRMan uses camera
space by default), but it is possible to
convert the point to object, world, texture or some other space within the
shader. On point can be transformed to a different space using the
<I>transform</I> statement. For example:
<PRE>
float y = ycomp(transform("object",P));
</PRE>
will convert the current point to object space and return the Y component
of the new point into the float variable y. The other vector type is also
a 3 element array of float values that specify a color. A <I>color</I>
type variable can be defined as follows:
<PRE>
color Cp = color (0.5, 0.5, 0.5);
</PRE>
<BR>
&nbsp; &nbsp; &nbsp;
Expressions in the shading language follow the same rules of precedence
that are used in the C language. The only two expressions that are new to
shaders are the Dot Product and the Cross Product. The Dot Product is
used to measure the angle between two vectors and is denoted by a period
(.). Dot Products work on point variables.
The Cross Product is often used to find the normal vector
at a point given two nonparallel vectors tangent to the surface at a given
point. The Cross Product only works on points, is denoted by a caret (^)
and returns a point value.
<P>
<A NAME="functions"></A>
<B><FONT COLOR="#335533">
Functions
</FONT></B>
<BR>
&nbsp; &nbsp; &nbsp;
A shader need not be a completely self contained entity. It can call
external routines, known as functions. The RenderMan Interface
Specificatoin predefines a large number of functions that
are available to shader authors using BMRT. The following list is just
a sample of these predefined functions:
<UL>
<LI>Math functions such as sin(), cos(), pow(), exp(), sqrt() and log().
<LI>Math functions such as min(), max() and clamp().
<LI>Derivative functions Du(), Dv(), and Deriv() which have versions
which work on float, color, and point values.
<LI>A noise() function for random value.
<LI>Geometric functions like area(), length() and distance().
<LI>Color functions like mix() which mixes two of its arguments based on
a third argument.
<LI>Shading and Lighting functions such as specular() and phong()
<LI>Texture map functions for using texture maps within shaders
</UL>
This is not a comprehensive list, but it provides a sample of the
functions available to the shader author. Many functions operate on more
than one data type (such as points or colors). Each can be used to
calculate a new color, point, or float value which can then be applied to
the current surface point.
<BR>
&nbsp; &nbsp; &nbsp;
Shaders can use their own set of functions defined locally. In fact, its
often helpful to put functions into a function library that can be included
in a shader using the #include directive. For example, the
<A HREF="http://www.cgrg.ohio-state.edu/~smay/RManNotes/index.html">
RManNotes Web site</A>
provides a function library called "rmannotes.sl" which contains a
<I>pulse()</I> function that can be used to create lines on a surface. If
we were to use this function in the matte shader example, it might look
something like this:
<PRE>
#include "rmannotes.sl"
surface matte (
float Ka = 1;
float Kd = 1;
)
{
point Nf;
float fuzz = 0.05
color Ol;
/*
* Calculate the normal which is facing the
* direction that points towards the camera.
*/
Nf = faceforward (normalize(N),I);
Ol = pulse(0.35, 0.65, fuzz, s);
Oi = Os*Ol;
Ci = Os * Cs * (Ka * ambient() + Kd * diffuse(Nf));
}
</PRE>
The actual function is defined in the rmmannotes.sl file as
<PRE>
#define pulse(a,b,fuzz,x) (smoothstep((a)-(fuzz),(a),(x)) - \
smoothstep((b)-(fuzz),(b),(x)))
</PRE>
A shader could just as easily contain the #defined value directly without
including another file, but if the function is useful shader authors may
wish to keep them in a separate library similar to rmmannotes.sl. In this
example, the variable s is the left-to-right component of the current
texture coordinate. "s" is a component of the <I>texture space</I>, which
we'll cover in the section on coordinate systems. "s" is a global variable
which is why it is not defined within the sample code.
<P>
Note: This particular example might not be very useful. It is just meant to
show how to include functions from a function library.
<P>
&nbsp; &nbsp; &nbsp;
Functions are only callable by the shader, not directly by the renderer.
This means a function cannot be used directly in a RIB file or referenced
using the C binding to the RenderMan Interface. Functions cannot be
recursive - they cannot call themselves. Also, all variables passed to
functions are passed by reference, not by value. It is important to
remember this last item so that your function doesn't inadvertantly make
changes to variables you were not expecting.
<P>
<A NAME="statements"></A>
<B><FONT COLOR="#335533">
Statements
</FONT></B>
<BR>
&nbsp; &nbsp; &nbsp;
The shading language provides the following statements for flow control:
<UL>
<LI><B>if-then-else</B>
<LI><B>while (</B>boolean expression<B>)</B> <I>statement</I>
<LI><B>for (</B>expr; boolean expr; expr<B>)</B> <I>statement</I>
<LI><B>break [</B>n<B>]</B> - "n" is the number of nested levels to exit from
<LI><B>continue [</B>n<B>]</B> -
"n" is the number of nested levels to exit from
<LI><B>return </B> expression
</UL>
All of these act just like their C counterparts.
<P>
<A NAME="coordinates"></A>
<B><FONT COLOR="#335533">
Coordinate Systems
</FONT></B>
<BR>
&nbsp; &nbsp; &nbsp;
There are number of coordinate systems used by RenderMan. Some of these I
find easy to understand by themselves, others are more difficult -
especially when used within shaders. In a shader, the surface of an object
is mapped to a 2 dimensional rectangular grid. This grid runs from
coordinates (0,0) in the upper left corner to (1,1) in the lower right
corner. The grid is overlayed on the surface, so on a rectangular patch
the mapping is obvious. On a sphere the upper corners of the grid map to
the same point on the top of the sphere. This grid is known as
<I>parameter space</I> and any point in this space is referred to by the
global variables <I>u</I> and <I>v</I>. For example, a point on the
surface which is in the exact center of the grid would have (u,v)
coordinates (.5, .5).
<BR>
&nbsp; &nbsp; &nbsp;
Similar to parameter space is <I>texture space</I>. Texture space is a
mapping of a texture map that also runs from 0 to 1, but the variables used
for texture space are <I>s</I> and <I>t</I>. By default, texture space is
equivalent to parameter space unless either vertex variables (variables
applied to vertices of primitive objects like patches or polygons) or the
TextureCoordinates statement have modified the texture space of the primitive
being shaded. Using the default then, a texture map image would have its upper
left corner mapped to the upper left corner of the parameter space grid
overlying the objects surface, and the lower right corner of the image
would be mapped to the lower right corner of the grid. The image would
therefore cover the entire object. Since the texture space does not have
to be equivalent to parameter space it would be possible to map an image to
only a portion of an object. Unfortunately, I didn't get far enough this
month to provide an example of how to do this. Maybe next month.
<BR>
&nbsp; &nbsp; &nbsp;
There are other spaces as well: world space, object space, and shader space.
How each of these affects the shading and texturing characteristics is not
completely clear to me yet. Shader space is the default space in which
shaders operate, but points in shader space can be transformed to world or
object space before being operated on. I don't know exactly what this
means or why you'd want to do it just yet
<P>
<A NAME="format"></A>
<H2>6. Format of a shader file</H2>
&nbsp; &nbsp; &nbsp;
Shader files are fairly free form, but there are
methodologies that can be used to make writing shaders easier and the code
more understandable. In his
RManNotes [<A HREF="#ref7">7</A>], Stephen F. May writes
<BLOCKQUOTE>
One of the most fundamental problem solving techniques is "divide and
conquer." That is, break down a complex problem into simpler parts;
solve the simpler parts; then combine those parts to
solve the original complex problem.
<P>
In shaders, [we] break down complicated surface patterns and textures into
layers. Each layer should be fairly easy to write (if not, then we can
break the layer into sub-layers). Then, [we] combine the layers by
compositing.
</BLOCKQUOTE>
The basic structure of a shader is similar to a procedure in C - the shader
is declared to be a particular type (surface, displacement, and so forth)
and a set of typed parameters are given. Unlike C, however, shader
parameters are required to have default values provided. In this way a
shader may be instanced without the use of any instance variables. If any
of the parameters are specified with instance variables then the value in
the instance variable overrides the parameters default value. An
minimalist shader might look like the following:
<PRE>
surface null ()
{
}
</PRE>
In fact, this is exactly the definition of the null shader. Don't ask me
why such a shader exists. I'm sure the authors of the specification had a
reason. I just don't know what it is. Adding a few parameters, we start
to see the matte shader forming:
<PRE>
surface matte (
float Ka = 1;
float Kd = 1;
)
{
}
</PRE>
The parameters Ka and Kd have their default values provided. Note that Ka
is commonly used in the shaders in Guido Quaroni's archive of shaders to
represent a scaling factor for ambient light. Similarly, Kd is used to
scale diffuse light. These are not global variables, but they are well
known variables, much like "i", "j", and "k" are often used as counters in
C source code (a throwback to the heady days of Fortran programming).
<BR>
&nbsp; &nbsp; &nbsp;
After the declaration of the shader and its parameters comes the set of
local variables and the shader code that does the "real work". Again, we
look at the matte shader:
<PRE>
#include "rmannotes.sl"
surface matte (
float Ka = 1;
float Kd = 1;
)
{
point Nf;
float fuzz = 0.05
color Ol;
/*
* Calculate the normal which is facing the
* direction that points towards the camera.
*/
Nf = faceforward (normalize(N),I);
Ol = pulse(0.35, 0.65, fuzz, s);
Oi = Os*Ol;
Ci = Os * Cs * (Ka * ambient() + Kd * diffuse(Nf));
}
</PRE>
Nothing special here. It looks very much like your average C procedure.
Now we get into methodologies. May [<A HREF="#ref8">8</A>] shows us how a
layered shader's psuedo-code might look:
<PRE>
surface banana(...)
{
/* background (layer 0) */
surface_color = yellow-green variations;
/* layer 1 */
layer = fibers;
surface_color = composite layer on surface_color;
/* layer 2 */
layer = bruises;
surface_color = composite layer on surface_color;
/* layer 3 */
layer = bites;
surface_color = composite layer on surface_color;
/* illumination */
surface_color = illumination based on surface_color
and illum params;
/* output */
Ci = surface_color;
}
</PRE>
What is happening here is that the lowest level applies yellow-and green
colors to the surface, after which a second layer has fiber colors
composited (blended or overlayed) in. This continues for each of 4 defined
layers (0 through 3) plus an illumination calculation to determine the
relative brightness of the current point. Finally, the newly computed
surface color is ouput via a global variable.
Using this sort of methodology makes writing a shader much easier as well
as allowing other shader authors to debug and/or extend the shader in the
future. A shader file is therefore sort of bottom-up design, where the
bottom layers of the surface are calculated first and the topmost layers
are computed last.
<P>
<A NAME="texture-maps"></A>
<H2>7. A word about texture maps</H2>
&nbsp; &nbsp; &nbsp;
As discussed earlier, texture maps are images mapped from 0 to 1 from left
to right and top to bottom upon a surface. Every sample in the image is
interpolated between 0 and 1. The mapping does not have to apply to the
entire surface of an object, however, and when used in conjunction with the
parameter space of the surface (the u,v coordinates) it should be possible
to map an image to a section of a surface.
<BR>
&nbsp; &nbsp; &nbsp;
Unfortunately, I wasn't able to determine exactly how to use this knowledge
for the image I submitted to the IRTC this month. Had I figured it out
in time, I could have provided text labels on the bindings of the books in
the bookcases for that scene. Hopefully, I'll figure this out in time for
the next article on BMRT and can provide an example on how to apply texture
maps to portions of surfaces.
<P>
<A NAME="examples"></A>
<H2>8. Working examples</H2>
<BR>
&nbsp; &nbsp; &nbsp;
The best way to actually learn how to write a shader is to get down and
dirty in the bowels of a few examples. All the references listed in the
bibliography have much better explanations for the exaples I'm about to
describe, but these should be easy enough to follow for novices.
<P>
<A NAME="examples-1"></A>
<FONT size=3>
<A HREF="./source/crosstile.sl">
<B>A colored cross pattern</B></A>
</FONT>
<BR>
&nbsp; &nbsp; &nbsp;
This example is taken verbatim from RManNotes by Stephen F. May.
The shader creates a two color cross pattern. In this example the pattern
is applied to a simple plane (a bilinear patch). Take a look at the
<A HREF="./source/crosstile.sl">source code</A>.
<PRE>
color surface_color, layer_color;
color surface_opac, layer_opac;
</PRE>
<table>
<tr>
<td valign=top>
The first thing you notice is that this shader defines two local
color variables: surface_color and layer_color.
The layer_color variable is used to compute the current layers color.
The surface_color variable is used to composite the various layers
of the shader. Two other variables, surface_opacity and
layer_opacity, work similarly for the opacity of the current layer.
<BR>
&nbsp; &nbsp; &nbsp;
The first layer is a verticle stripe. The shader defines the color
for this layer and then determines the opacity for the current point
by using a function called <I>pulse()</I>. This is a function
provided by May in his "rmannotes.sl" function library. The pulse()
function allows the edges of the stripes in this shader to flow
smoothly from one color to another (take a look at the edges of
the stripes in the
sample image). pulse() uses the fuzz variable to determine how
fuzzy the edges will be.
Finaly, for each layer the layers color and opacity
are blended together to get the new surface color. The <I>blend()</I>
function is also part of rmannotes.sl and is an extension of the
RenderMan Interface's mix() function, which mixes color and opacity
values.
<td valign=top>
<table>
<tr>
<td align=center bgcolor=#000000>
<IMG SRC="./gx/hammel/crosstile.jpg"
ALT="Tiled cross pattern" ALIGN="middle"
HSPACE="0" WIDTH="121" HEIGHT="151">
<BR clear=both>
<FONT color=#ffffff>Figure 4</FONT>
</td>
<tr>
<td bgcolor=#AAAAAA align=center>
<A HREF="./source/crosstile.rib">
RIB Source code for this example</A>
</td>
</table>
</table>
&nbsp; &nbsp; &nbsp;
Finally, the incident rays opacity global variable is set along
with its color.
<PRE>
Oi = surface_opac;
Ci = surface_opac * surface_color;
</PRE>
These two values are used by the renderer to compute
pixel values in the output image.
<P>
<A NAME="examples-2"></A>
<A HREF="./source/RCScreen.sl">
<FONT size=3><B>Adding opacity - a wireframe shader</B></FONT>
</A>
<BR>
<table>
<tr>
<td valign=top>
&nbsp; &nbsp; &nbsp;
This example is taken from the RenderMan Companion. It shows how a shader
can be used to cut out portions of a solid surface. We use the first
example as a backdrop for a sphere that is shaded with the screen() shader
from the RenderMan Companion text (the name of the shader as used here is
slightly different because it is taken from the collection of shaders from
Guido Quaroni, who changed the names of some shaders to reflect their
origins). First lets look at the sceen using the "plastic" shader
(which comes as a default shader in the BRMT distribution). Figure 5 shows
how this scene renders. The sphere is solid in this example. The
RIB code for this contains the following lines:
<PRE>
AttributeBegin
Color [ 1.0 0.5 0.5 ]
Surface "plastic"
Sphere 1 -1 1 360
AttributeEnd
</PRE>
In Figure 6 the sphere has been changed to a wireframe surface. The
only difference between this scene and Figure 5 is the surface shader used.
For Figure 6 the rib code looks like this:
<PRE>
AttributeBegin
Color [ 1.0 0.5 0.5 ]
Surface "RCScreen"
Sphere 1 -1 1 360
AttributeEnd
</PRE>
The rest of the RIBs are exactly the same. Now lets look at the
<A HREF="./source/RCScreen.sl">screen() shader code</A>.
<PRE>
surface
RCScreen(
float Ks = .5,
Kd = .5,
Ka = .1,
roughness = .1,
density = .25,
frequency = 20;
color specularcolor = color (1,1,1) )
{
varying point Nf =
faceforward( normalize(N), I );
point V = normalize(-I);
</PRE>
<td valign=top>
<table>
<tr>
<td align=center bgcolor=#000000>
<IMG SRC="./gx/hammel/wireframe1.jpg"
ALT="A Wireframed sphere - without wireframe" ALIGN="middle"
HSPACE="0" WIDTH="139" HEIGHT="152">
<BR clear=both>
<FONT color=#ffffff>Figure 5</FONT>
</td>
<tr>
<td bgcolor=#AAAAAA align=center>
<A HREF="./source/wireframe1.rib">
RIB Source code for this example</A>
</td>
<tr>
<td align=center bgcolor=#000000>
<IMG SRC="./gx/hammel/wireframe2.jpg"
ALT="A Wireframed sphere - with wireframe" ALIGN="middle"
HSPACE="0" WIDTH="138" HEIGHT="152">
<BR clear=both>
<FONT color=#ffffff>Figure 6</FONT>
</td>
<tr>
<td bgcolor=#AAAAAA align=center>
<A HREF="./source/wireframe2.rib">
RIB Source code for this example</A>
</td>
<tr>
<td align=center bgcolor=#000000>
<IMG SRC="./gx/hammel/wireframe3.jpg"
ALT="A Wireframed sphere - thinner grid lines" ALIGN="middle"
HSPACE="0" WIDTH="138" HEIGHT="152">
<BR clear=both>
<FONT color=#ffffff>Figure 7</FONT>
</td>
<tr>
<td bgcolor=#AAAAAA align=center>
<A HREF="./source/wireframe3.rib">
RIB Source code for this example</A>
</td>
</table>
</table>
<PRE>
if( mod(s*frequency,1) < density ||
mod(t*frequency,1) < density )
Oi = 1.0;
else
Oi = 0.0;
Ci = Oi * ( Cs * ( Ka*ambient() + Kd*diffuse(Nf) ) +
specularcolor*Ks* specular(Nf,V,roughness));
}
</PRE>
<BR>
&nbsp; &nbsp; &nbsp;
The local variable V is defined to be the normalized vector for the
incident light rays direction. The incident light ray direction is the
direction from which the camera views the current surface coordinate.
This value is used later to compute the specular highlight to be used on
the portion of the surface which will not be cut out of the sphere.
<BR>
&nbsp; &nbsp; &nbsp;
The next thing the shader does is to compute the modulo of the s component
of the texture space times the frequency of the grid lines of the
wireframe. This value is always less than 1 (the modulo of s*frequency is
the remainder left for n*1 < s*frequency for some value n). If this value
is also less then the density then the current coordinate on the surface is
part of the visible wireframe that traverses the surface horizontally.
Likewise, the same modulo is computed for t*frequency and if this value is
also less than the density then the current coordinate point is on one of
the visible verticle grid lines of the wireframe. Any point for which the
module of either of these is greater than the density is rendered
completely transparent. The last line computes the grid lines based on the
current surface color and a slightly metallic lighting model.
<BR>
&nbsp; &nbsp; &nbsp;
The default value for the density is .25, which means that approximately
1/4 of the surface will be visible wireframe. Changing the value with an
instance variable to .1 would cause the the wireframe grid lines to become
thinner. Figure 7 shows an example of this. Changing the frequency to a
smaller number would cause fewer grid lines to be rendered.
<P>
<A NAME="examples-3"></A>
<A HREF="./source/MJH3HolePaper.sl">
<FONT size=3><B>A simple paper shader</B></FONT>
</A>
<BR>
&nbsp; &nbsp; &nbsp;
While working on my entry for the March/April 1997 round of the IRTC I
wrote my first shader - a shader to simulate 3 holed notebook paper. This
simplistic shader offers some of the characteristics of the previous
examples in producing regularly spaced horizontal and verticle lines plus
the added feature of fully transparent circular regions that are positioned
by instance variables.
&nbsp; &nbsp; &nbsp;
We start by defining the parameters needed by the shader. There are quite
a few more parameters than the other shaders. The reason for this is that
this shader works on features which are not quite so symmetrical. You can
also probably chalk it up to my inexperience.
<PRE>
color hcolor = color "rgb" (0, 0, 1);
color vcolor = color "rgb" (1, 0, 0);
float hfreq = 34;
float vfreq = 6;
float skip = 4;
float paper_height = 11;
float paper_width = 8.5;
float density = .03125;
float holeoffset = .09325;
float holeradius = .01975;
float hole1 = 2.6;
float hole2 = 18;
float hole3 = 31.25;
</PRE>
The colors of the horizontal and vertical lines come first. There are, by
default, 34 lines on the paper with the first 4 "skipped" to give the small
header space at the top of the paper. The vertical frequency is used to
divide the paper in n equal vertical blocks across the page. This is used
to determine the location of the single verticle stripe. We'll look at
this again in a moment.
<BR>
&nbsp; &nbsp; &nbsp;
The paper height and width are used to map the parameter space into the
correct dimensions for ordinary notebook paper. The density parameter is
the width of each of the visible lines (horizontal and vertical) on the
paper. The hole offset defines the distance from the left edge of the
paper to the center point of the 3 holes to be punched out. The holeradius is
the radius of the holes and the hole1-hole3 parameters give the horizontal
line over which the center of that hole will live. For example, for hole1
the center of the hole is 2.6 horizontal stripes down. Actually, the
horizontal stripes are created at the top of equally sized horizontal
blocks, and the hole1-hole3 values are number of horizontal blocks to
traverse down the paper for the holes center.
Now lets look at how the lines are created.
<table>
<td valign=top width=60%>
<PRE>
surface_color = Cs;
</PRE>
This line simply initializes a local variable to the current color of
the surface. We'll use this value in computing a new surface color
based on whether the point is on a horizontal or vertical line.
<PRE>
/*
* Layer 1 - horizontal stripes.
* There is one stripe for every
* horizontal block. The stripe is
* "density" thick and starts at the top of
* each block, except for the first "skip"
* blocks.
*/
tt = t*paper_height;
for ( horiz=skip; horiz&lthfreq; horiz=horiz+1 )
{
min = horiz*hblock;
max = min+density;
val = smoothstep(min, max, tt);
if ( val != 0 && val != 1 )
surface_color = mix(hcolor, Cs, val);
}
</PRE>
This loop runs through all the horizontal blocks on the paper
(defined by the hfreq parameter) and determines if the point
lies between the top of the block and the top of the block plus
the width of a horizontal line (specified with the density parameter).
<td align=center valign=top width=39%>
<table>
<tr>
<td align=center bgcolor=#000000>
<IMG SRC="./gx/hammel/paper1.jpg"
ALT="3 Holed paper" ALIGN="middle"
HSPACE="0" WIDTH="122" HEIGHT="174">
<BR clear=both>
<FONT color=#ffffff>Figure 8</FONT>
</td>
<tr>
<td bgcolor=#AAAAAA align=center>
<A HREF="./source/paper.rib">
RIB Source code for this example</A>
</td>
<tr>
<td align=center bgcolor=#000000>
<IMG SRC="./gx/hammel/paper2.jpg"
ALT="3 Holed paper - thicker lines" ALIGN="middle"
HSPACE="0" WIDTH="122" HEIGHT="174">
<BR clear=both>
<FONT color=#ffffff>Figure 8</FONT>
</td>
</table>
</table>
The smoothstep() function is part of the standard RenderMan functions
and returns a value that is between 0 and 1, inclusive, that shows where
"tt" sits between the min and max values. If this value is not at
either end then the current surface point lies in the bounds of a
horizontal line. The point is given the "hcolor" value mixed with the
current surface color We mix the colors in order to allow
the edges of the lines to flow smoothly between the horizontal lines
color and the color of the paper. In other words, this allows for
antialiasing the horizontal lines. The problem with this is - it doesn't
work. It only aliases one side of the line, I think. In any case, you can
see from Figure 8 that the result does not quite give a smooth,
solid set of lines.
<BR>
&nbsp; &nbsp; &nbsp;
An alternative approach would be to change the mix() function call (which
is part of the RenderMan shading lanague standard functions) to a more
simple mixture of the line color with the value returned by smoothstep().
This code would look like this:
<PRE>
min = horiz*hblock;
max = min+density;
val = smoothstep(min, max, tt);
if ( val != 0 && val != 1 )
surface_color = val*hcolor;
</PRE>
Alternatively, the line color could be used on its own, without combining
it with the value returned from the smooth step. This gives a very jagged
line, but the line is much darker even when used with smaller line
densities. The result from using the line color alone (with a smaller line
density) can be seen in Figure 9.
<PRE>
/* Layer 2 - vertical stripe */
ss = s*paper_width;
min = vblock;
max = min+density;
val = smoothstep(min, max, ss);
if ( val != 0 && val != 1 )
surface_color = mix(vcolor, Cs, val);
</PRE>
This next bit of code does exactly the same as the previous code
except it operates on the vertical line. Since there is only one
verticle line there is no need to check every vertical block, only
the one which will contain the visible stripe (which is specified
with the vblock parameter).
<BR>
&nbsp; &nbsp; &nbsp;
Finally we look at the hole punches. The center of the holes are computed
relative to the left edge of the paper:
<PRE>
shole = holeoffset*paper_width;
ss = s*paper_height;
tt = t*paper_height;
pos = (ss,tt,0);
</PRE>
Note that we use the papers height for converting the ss,tt variables into
the scale of the paper width and height. Why? Because if we used the
width for ss we would end up with eliptical holes. There is probably a
better way to deal with this problem (of making the holes circular) but
this method worked for me.
<BR>
&nbsp; &nbsp; &nbsp;
For each hole, the current s,t coordinates distance from the hole
centers is computed. If the distance is less than the holes radius then
the opacity for the incident ray is set to completely transparent.
<PRE>
/* First Hole */
thole = hole1*hblock;
hpos = (shole, thole, 0);
Oi = filterstep (holeradius*paper_width,
distance(pos,hpos));
/* Second Hole */
thole = hole2*hblock;
hpos = (shole, thole, 0);
Oi *= filterstep (holeradius*paper_width,
distance(pos,hpos));
/* Third Hole */
thole = hole3*hblock;
hpos = (shole, thole, 0);
Oi *= filterstep (holeradius*paper_width,
distance(pos,hpos));
</PRE>
Filterstep is, again, a standard function in the RenderMan specification.
However, this function was not documented by either the RenderMan Interface
Specification or the RenderMan Companion. According to Larry Gritz
<BLOCKQUOTE>
The filterstep() function is identical to step, except that it is
analytically antialiased. Similar to the texture() function,
filterstep actually takes the derivative of its second argument, and
"fades in" at a rate dependent on how fast that variable is changing.
In technical terms, it returns the convolution of the step function
with a filter whose width is about the size of a pixel. So, no
jaggies.
</BLOCKQUOTE>
Thus, using filterstep() helped to antialias the edges of the holes
(although its not that obvious from such a small image given in Figures 8
and 9). I didn't try it, but I bet filterstep() could probably be used to
fix the problems with the horizontal and vertical lines.
<P>
<A NAME="examples-4"></A>
<A HREF="./source/PXDecal.sl">
<FONT size=3><B>A textured mapped chalkboard</B></FONT>
</A>
<BR>
&nbsp; &nbsp; &nbsp;
This simple texture map example is used in my <I>Post Detention</I> image
which I entered in the March/April 1997 IRTC. The actual shader is taken
from the archive collection by Guido Quaroni, and the shader originally
comes from Larry Knott (who I presume works at Pixar). I didn't add an
image of this since all you would see would be the original image mapped on a
flat plane, which really doesn't show anything useful. If you want to take
a look at the chalkboard in a complete scene, take a look at the
<A HREF="more-musings.html#1">companion article</A>
in this months Graphics Muse column.
<BR>
&nbsp; &nbsp; &nbsp;
Like the other shader examples, this one is fairly straightforward. An
image filename is passed in the <I>texturename</I> parameter. Note that
image files must be TIFF files for use with BMRT. The texture coordinates
are used to grab a value from the image file which is then combined with
the ambient and diffuse lighting for the incident ray. If a specular
highlight has been specified (which it is by default in the Ks parameter)
then a specular highlight is added to the incident ray. Finally, the
output value, Ci, is combined with the surfaces opacity for the final color
to be used by the current surface point.
<P>
<A NAME="examples-5"></A>
<A HREF="./source/RCThreads.sl">
<FONT size=3><B>Displacement map example</B></FONT>
</A>
<BR>
&nbsp; &nbsp; &nbsp;
We've already seen an example of displacement maps using the threads()
shader. Lets take a quick look at the shader code:
<PRE>
magnitude = (sin( PI*2*(t*frequency +
s + phase))+offset) * Km;
</PRE>
Here, the displacement of the surface point is determined by using a
phased sinusoidal. The t variable determines the position lengthwise
across the surface and s is used to cause the spiraling effect. The next
bit of code
<PRE>
if( t > (1-dampzone))
magnitude *= (1.0-t) / dampzone;
else if( t < dampzone )
magnitude *= t / dampzone;
</PRE>
causes the ends of the surface, in our case a cylinder, to revert to the
original shape. For our example that means this forces the shader to leave
the ends circular. This helps to keep the object that has been threaded in
a shape that is easily joined to other objects. In the RenderMan
Companion, the threaded cylinder is joined to a glass bulb to form a
light bulb. Finally, the last two lines
<PRE>
P += normalize(N) * magnitude;
N = calculatenormal(P);
</PRE>
cause the point to be moved and the normal for the new point to be
calculated. In this way the point visually appears to have moved, which
indeed it has.
<P>
Next month I planned on doing the 3rd part of this 3 part BMRT series. I
think taking 2 months between articles worked well for me this time since
it allowed me a little more time to dig deeper. Plan on the final article
on BMRT in this series in the July issue of the Graphics Muse. Till then,
happy rendering.
<table width=100%>
<tr>
<td bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
</table>
<OL>
<LH><B>Bibliography</B></LH>
<LI>
<A NAME="ref1"></A>
Ebert, Musgrave, Peachy, Perlin, Worley.
<I>Texturing and Modeling: A Procedural Approach</I>,
5-6; AP Professional (Academic Press), 1994
<LI>
<A NAME="ref2"></A>
Upstill, Steve.
<I>The RenderMan Companion - A Programmer's Guide to
Realistic Computer Graphics</I>,
277-278; Addison Wesley, 1989
<LI>
<A NAME="ref3"></A>
<I>The RenderMan Interface Specification, Version 3.1</I>
112-113; Pixar, Septermber 1989
<LI>
<A NAME="ref4"></A>
Upstill, Steve.
<I>The RenderMan Companion - A Programmer's Guide to
Realistic Computer Graphics</I>,
color plates section; Addison Wesley, 1989
<LI>
<A NAME="ref5"></A>
Upstill, Steve.
<I>The RenderMan Companion - A Programmer's Guide to
Realistic Computer Graphics</I>,
279; Addison Wesley, 1989
<LI>
<A NAME="ref6"></A>
<I>The RenderMan Interface Specification, Version 3.1</I>
110-114; Pixar, Septermber 1989
<LI>
<A NAME="ref7"></A>
<A HREF="http://www.cgrg.ohio-state.edu/~smay/RManNotes/WritingShaders/intro.html#method">
<I>RManNotes</I></A>
"Writing RenderMan Shaders - Why follow a methodolgy?";
Stephen F. May, Copyright &copy 1995, 1996
<LI>
<A NAME="ref8"></A>
<A HREF="http://www.cgrg.ohio-state.edu/~smay/RManNotes/WritingShaders/intro.html#approach">
<I>RManNotes</I></A>
"Writing RenderMan Shaders - The Layered Approach";
Stephen F. May, Copyright &copy 1995, 1996
</OL>
<table width=100%>
<tr>
<td bgcolor="#000000" cellpadding=0 cellspacing=0 valign=top>
<IMG SRC="../gx/hammel/cleardot.gif" ALT="indent" ALIGN="left"
HSPACE="0" WIDTH="0" HEIGHT="0"></td>
<tr>
<td align=right>
<FONT size=1>
&copy 1996 by <A HREF="mailto:mjhammel@csn.net">Michael J. Hammel</A>
</FONT>
</table>
<H4>
&quot;Linux Gazette...<I>making Linux just a little more fun!</I>&quot;
</H4>
<P> <HR> <P>
<!--===================================================================-->
<center>
<H2>Kandinski</H2>
<H4>By Jeff Hohensee,
<a href="mailto:"oot@casper.com">ott@casper.com</a></H4>
</center>
<P> <HR>
<p>Kandinski is my new pre-pre-pre-beta program which generates a picture
file from a MIDI file. It does so based on my cycluphonic method of
correlating colors to musical pitches. The few careful observers who have
seen previous implementations of cycluphonics agree that it gives visual
events which seem to sympathize with the generating music, in terms of
implied feeling, better than previous "color organ" methods.
Kandinski was written with pfe under Linux on a 486. It should be easy to
port to another ANSI Forth system, as I am rusty at Forth, and the task at
hand didn't call for any trickery, and I avoided the Linux-specific stuff
in pfe, mostly because I couldn't find much documentation on it.
The code presented here creates a .ppm image file on a selectable track by
track basis. The piano envelope option is not implemented yet, just organ.
.ppm files can be converted to just about any image format with the unix
pbmplus tools, and are viewable in Linux with zgv.
The crucial cycluphonic element in Kandinski is the "cycle" construct,
a lookup table which Kandinski uses to map a 12 hue color wheel to the
Cycle of Fifths. That's the crux of cycluphonics. If you use this code, or
cycluphonics, give credit where due.
<h3>How Kandinski operates ( I hope )</h3>
Copy a MIDI file with some tonal music to filename in.mid .
Run your ANSI Forth in the same directory. Include the Kandinski code into
your dictionary. Type main at the ok prompt. Kandinski will check in.mid
for a MIDI header. If in.mid is a midi file, Kandinski will traverse
tracks until it finds a noteon message. It will then tell you a bit about
the track and ask you if you want to make a picture of it. Hit y and it
will ask you if you want to use a piano or an organ type volume envelope.
The piano option is curently just a stub. Kandinski will then ask you to
hit a key to seed the filename randomizer. Kandinski will then create a
picture file with a filename of the form kanrrrrr.ppm, where r is a random
letter. The track portion of the program repeats if there are more tracks
with notes. The pictures created by Kandinski are 640 by 80 pixels, 24
bits color depth. I will soon be putting some Kandinski output up at
<a href="http://cqi.com/~humbubba">http://cqi.com/~humbubba</a><br>
<pre>
( kandinski )
( ANSI Forth sourcecode Rick Hohensee begun 199703 )
( A MIDIfile-to-still-picture implementation of my Cycluphonic method
of correlating colors and musical pitches. )
( used i486 Slackware Linux from the InfoMagic LDR sept 96, pfe,
Jeff Glatt's MIDI docs, dpans7 )
( redistribution permission contingent on authorship credit )
( default number base of file is.... ) decimal
( app notes, pfe file-postition is a DOUBLE!
MIDI sizes are SINGLEs
YEESH! "f0" is a variable! AAAAARRRRGGG!!!
hex f0 decimal . doesn't work as wished. )
( my prefered tools, jigs and cheats )
: binary decimal 2 base ! ;
: .base base @ dup decimal . base ! ;
: walk ." " key drop ;
: 0s ( wipe data stack )
depth dup if 0 do drop loop else drop then ;
: paddump ( [ count --- ] counted dump from pad )
pad swap dump ;
( app related ....)
0 value deltasum
2variable trkend 0 0 trkend 2!
0 value dpp ( deltas per pixel )
create rgbs 640 3 * allot
0 value trk#
variable midifile
0 value pbmfile
create organstate 128 allot
organstate 128 0 fill ( pfe allot leaves an "allot" string in the alloted
space )
create 12state 12 allot
12state 12 0 fill
0 value redac
0 value greenac
0 value blueac
0 value backfoot
create cycle 0 , 7 , 2 , 9 , 4 , 11 , 6 , 1 , 8 , 3 , 10 , 5 ,
create wheelred 12 allot
255 c, 255 c, 255 c, 127 c, 0 c, 0 c, 0 c, 0 c, 0 c, 127 c, 255 c, 255 c,
create wheelgreen 12 allot
0 c, 127 c, 255 c, 255 c, 255 c, 255 c, 255 c, 127 c, 0 c, 0 c, 0 c, 0 c,
create wheelblue 12 allot
0 c, 0 c, 0 c, 0 c, 0 c, 127 c, 255 c, 255 c, 255 c, 255 c, 255 c, 127 c,
0 value fid
create ppm
ascii P c, ascii 6 c, 10 c, ascii 6 c, ascii 4 c, ascii 0 c,
bl c, ascii 8 c, ascii 0 c,
bl c, ascii 2 c, ascii 5 c, ascii 5 c,
: msboff 127 and ;
: openin ( opens a file called in.mid in current dir
which can then be referenced via midifile @ )
S" in.mid" r/w bin open-file drop midifile ! ;
: in.mid ( --- fid_of_in.mid ) ( poorly factored, ) midifile @ ;
: inpos ( --- 2inpos ) ( get file position in in.mid )
midifile @ file-position drop ( ior) ;
: inpeek ( [ count --- ] counted read from in.mid to pad )
pad swap
midifile @ read-file drop ;
: trksize ( --- trksize ) ( DOES move inpos )
( build a 32 bit track size cell from the WRONGendian value
, from body0 to body0 )
4 inpeek drop ( endianism translation )
pad c@ 24 lshift
pad 1 + c@ 16 lshift +
pad 2 + c@ 8 lshift +
pad 3 + c@ + ;
2variable prevpos
2variable starttrk 0 0 starttrk 2!
: filebound ( fid --- 0 if inside file )
dup >r file-position drop r> file-size drop 2swap d< ;
: hoptrk ( [ --- inbounds_flag ] body0 to next trk body0 )
trksize 8 + 0 inpos d+ in.mid reposition-file drop
in.mid filebound ;
0 value envelope
0 value noteons 0 value noteoffs
: hinybble 240 and ; ( f0 is a &$^%##%$ variable name! )
hex
0f constant lonybble
binary
: bit7 10000000 and ;
decimal
0 value delta
: bytein pad 1 in.mid read-file drop
1 <> if ( error) cr
." end of in.mid "
quit else pad c@ then ;
: bignum 0
begin bytein dup bit7
while
msboff swap 7 lshift +
repeat
swap 7 lshift + ;
: ignore ( n --- ) ( add n to inpos )
0 inpos d+ in.mid reposition-file drop ;
: ignoreto ( delimiter --- ) ( ignore filebytes to delimiter )
begin dup bytein = until drop ;
0 value moment
: mthd ( --- da position of MThD or fail )
77 ignoreto 84 ignoreto 104 ignoreto 100 ignoreto inpos ;
: mtrk 77 ignoreto 84 ignoreto 114 ignoreto 107 ignoreto inpos ;
: seed
." hit a key please " key
time&date 2drop drop + + + in.mid + ;
: 128to12 ( organstate to 12state, i.e. midinote#s to notename#s )
12state 12 0 fill
128 0 do
organstate i + c@ if
1 i 12 mod 12state + c!
then ( simple for now )
loop
;
: 12torgb 0 to redac 0 to greenac 0 to blueac
12 0 do
12state i + c@ if
i cells cycle + @
cells dup wheelred + @ redac + 2 / to redac
dup wheelgreen + @ greenac + 2 / to greenac
wheelblue + @ blueac + 2 / to blueac
then
loop ;
: orgtorgb ( pixel# --- )
128to12
12torgb
dup redac swap 3 * rgbs + c!
dup greenac swap 3 * 1 + rgbs + c!
blueac swap 3 * 2 + rgbs + c!
;
: reset ( --- ) ( actions on an FF status byte )
bytein case
0 of bignum ignore ." ff 00 ignored " endof
1 of ." text " bignum ignore endof
2 of ." copyright " bignum ignore endof
3 of ." trackname " bignum ignore endof
4 of ." inst name " bignum ignore endof
5 of ." lyric " bignum ignore endof
6 of ." flow marker " bignum ignore endof
7 of ." cue point, sample " bignum ignore endof
33 of 2 ignore ( port # ) endof
47 of ( ." last event of track " ) 1 ignore endof
81 of 4 ignore endof
84 of 6 ignore ." smte o/s ignored " endof
88 of 5 ignore ( time sig ) endof
( ." unknown reset ff thang " )
endcase ;
: sysex ( sysexbyte --- ) ( i.e. message with status hinyb of f )
dup case
240 of 247 ignoreto ." ignoring f0 to f7 " drop endof
241 of ." miditimecode, unsupported " drop endof
242 of ." song position pointer " drop endof
243 of ." song select " drop endof
244 of ." unimplemented f4 sysex " drop endof
245 of ." unimplemented f5 sysex " drop endof
246 of ." tune calibrate " drop endof
249 of ." unimplemented f9 sysex " drop endof
247 of ." discontinue f0/240 stream " drop endof
248 of ." midi clock " drop endof
250 of ." restart song " drop endof
251 of ." midi continue, flow " drop endof
252 of ." stop " drop endof
254 of ." active sense message " drop endof
253 of ." unimplemented fd sysex " drop endof
255 of reset endof
." impossible sysex "
endcase ;
: envelope? cr ." piano envelope or organ? (p=piano/other=organ) " key
ascii p = if -1 to envelope else 0 to envelope then ;
: message ( survey pass )
bytein dup hinybble case
128 of 2 ignore noteoffs 1 + to noteoffs drop endof
144 of noteons 1+ to noteons 2 ignore drop endof
160 of 2 ignore drop endof
176 of 2 ignore drop endof
192 of 2 ignore drop endof
208 of 2 ignore drop endof
224 of 2 ignore drop endof
240 of cr sysex endof
endcase ;
: pianooff ." pianooff " 2 ignore ;
: pianoon 2 ignore ;
: organoff 0 organstate bytein + c! 1 ignore ;
: organon -1 organstate bytein + c! 1 ignore ;
: messageagain ( processing pass )
bytein dup hinybble case
128 of envelope if pianooff else organoff then drop endof
144 of envelope if pianoon else organon then drop endof
160 of 2 ignore drop endof
176 of 2 ignore drop endof
192 of 2 ignore drop endof
208 of 2 ignore drop endof
224 of 2 ignore drop endof
240 of cr sysex endof
endcase ;
: random.kan ( create file[name] kan[random].ppm )
seed srand
ascii k pad c! ascii a pad 1 + c! ascii n pad 2 + c!
8 3 do 26 random 97 + i pad + c! loop
ascii . pad 8 + c! ascii p pad 9 + c! ascii p pad 10 + c!
ascii m pad 11 + c! ;
: makepic
random.kan
pad 12 r/w create-file drop to pbmfile ( new filename exists )
ppm 16 pbmfile write-file drop
80 0 do
rgbs 640 3 * pbmfile write-file drop
loop
;
: process
0 to deltasum 0 to noteons 0 to noteoffs
640 0 do ( i=pixel )
begin
( bignum backfoot )
bignum deltasum + to deltasum
messageagain
i dpp * deltasum >
while
repeat
( paint pixel )
i orgtorgb
loop
makepic
;
: survey ( a track )
inpos starttrk 2!
trksize 0 inpos d+ trkend 2!
0 to deltasum 0 to noteons 0 to noteoffs
begin
bignum deltasum + to deltasum
message
inpos trkend 2@ d<
while
repeat
;
: track survey
noteons if ." This track has notes.... "
cr ." noteons " noteons . ." noteoffs " noteoffs .
." MIDI clocks per pixel " deltasum 640 / dup to dpp .
cr ." wanna do a pic of this track? (y/other) " key ascii y = if
envelope?
starttrk 2@ in.mid reposition-file drop inpos d. walk
noteons . dpp if
process else ." less than one clock per pixel, no can do " walk then
then then
;
: typecheck
mthd
inpos 2dup 4 0 d= if ." apparent std MIDI seq file. Yay. "
else 16 0 d= if ." apparent RMID MIDI file. OK. " else
cr ." in.mid is apparently not a MIDI file " cr
." Copy MIDI file to be processed to in.mid " bye then then ;
: main 0 to trk#
openin typecheck
begin
trk# 1 + dup to trk#
mtrk
track
( bytein does a QUIT on end-of-file )
again
;
</pre>
<p>Separate documentation file for the Kandinski program
Rick Hohensee <a href="http://cqi.com/~humbubba">http://cqi.com/~humbubba</a>
or <a href="mailto:rickh@capaccess.org">rickh@capaccess.org</a>
please cc to <a href="mailto:humbubba@cqi.com">humbubba@cqi.com</a>
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1997, Jeff Hohensee <BR>
Published in Issue 17 of the Linux Gazette, May 1997</H5></center>
<!--===================================================================-->
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<!--===================================================================-->
<center>
<H2>1997 Linux Expo</H2>
<H4>By Jon "maddog" Hall
<a href="mailto:"maddog@zk3.dec.com">maddog@zk3.dec.com</a></H4>
</center>
<HR> <P>
<p>"Well, should we get one pitcher or two?" That was the question
that began the first unofficial event of the Linux Expo Thursday
night. A group of people, including Red Hat employees, some of the
speakers and a tired maddog were at the Carolina Brewery in
Chapel Hill, North Carolina. It was late, and I was the
last person to arrive."Two pitchers," I cried,"Now what
will you be drinking?"
<p>The next day, Friday April 4th started early, as I had to set up
the Linux International booth, as well as absorb all that was
happening. The event was held in the North Carolina
Biotechnology Center at Research Triangle Park. As I
approached the Biotech Center, I was met with a friendly
parking coordinator that reinforced the information that
"parking was scarce", and that most people had to park at
outlying lots. Fortunately Red Hat had arranged for shuttle
busses from those lots and from several of the hotels. Since our
car had an exhibitor's pass, we were able to park close to the
Biotech Center and unload our banners, handouts and stuffed
penguins.
<p>There was a large tent to the left outside of the building
containing the "Linux Expo Super Store" stocked with
Linux books, Linux bumper stickers, T-shirts (including
an excellently designed Expo shirt that said "Expose yourself to
Linux" with a front and rear view of a penguin holding open an
overcoat) and other interesting souvenir items. Further
to the left was an outdoor viewing area for the conference talks
that (due to the excellent weather) was a favorite spot for
people to view the technical talks for free, especially while
playing Frisbee. A raffle was held in the registration area,
and prizes were given away on an hourly basis.
Having registered, attendees were given a copy of the talks as
well as an event schedule.
<p>The event was held on two floors with the exhibits spread out on both. There
was another conference viewing area inside the building with TV
monitors, as well as the conference auditorium itself. There was
an Install Fest area (sponsored by the Washington D.C. Linux
User's Group, Linux Hardware Solutions and Red Hat Software),
where people brought their systems, received help with installing
Red Hat's latest release, and Olaf Kirch's kernel-based NFS
server was "stress tested" at the same time. Finally, there was a food
court area, where people could buy sandwiches, chips, soda and
other "software development food".
<p>There were fifteen vendors at the Expo, each with "table-top"
booths to display their wares. I prefer the "pipe-and-drape"
approach to trade shows rather than expensive booths, since I
would rather the vendors put more money into development of the
product and less into elaborate displays or floor shows with
unicycle riders who juggle things. While not all Linux vendors
were at Linux Expo, a wide spectrum of companies, including Linux
International, Cyclades, Numerical Algorithms Group, Linux
Hardware Solutions, Enhanced Software Technologies, Caldera,
Applix, Xess, WorkGroup Solutions, Stay Online, VA Research, Apex
Systems Integration, PromoX Systems and (of course) Red Hat
Software were present. One item being demonstrated at the Linux
Hardware Solutions booth was a free piece of software called [cw]em86[ecw]
that allowed an Intel/Linux binary to run without change on an
Alpha/Linux system. Being shown for the first time, it allowed
Applixware, Netscape and various other applications to execute as
if they had been ported to the system.
<p>Penguins abounded in various T-shirts, giveaways and objects
d'art. In fact, there were so many people there (I estimated 900
over the two-day event) with penguin "stuff", that I thought
I'd
had enough of penguins; but afterwards while wandering around Chapel Hill, Alan Cox found some
candy in the shape of penguins, so penguin "lust" started all
over again.
<p>The technical conference started off with a presentation by
Gilbert Coville of Apple Computer with a talk about the MkLinux
kernel. For people who were afraid that this would turn into a
"Red Hat Only" event, it was interesting that Gilbert's talk
opened the Expo and that a talk about the Debian Linux
Distribution (given by Bruce Perens) followed shortly after.
Bruce also discussed the graphics used in the making of Toy Story in
a separate presentation.
<p>Various presentations about hardware-specific ports were given.
Dave Miller talked about the "Next Generation SPARCLinux" as well
as the Free Software Development Model, and David Mosberger-Tang
talked about the Alpha Port, as well as methods, applicable to both Intel
and Alpha, for
speeding up your programs by paying attention to memory and
cache accesses.
<p>Other talks were more general across the Linux OS, such as Jeff
Uphoff's "Network File Locking", Alan Cox's "Tour of the Linux
Networking Stack", Peter Braam's "Coda Filesystem", Alexander
Yuriev's talk on the IPv4 family of protocols and infrastructure
and his talk on security, Michael Callahan's "Linux and Legacy
LANs", Eric Youngdale's "Beyond ELF", Olaf Kirch's "Linux Network
File System", Theodore Ts's "Ext2 File System: Design,
Implementation and the Future", Miguel de Icaza's talk on the new
RAID code and Daniel Quinlan's talk on the File System Hierarchy
Standard.
<p>To round out the list of talks and events was Dr. Greg
Wettstein's talk on "Working and Playing with others: Linux Grows
Up" and the Linux Bowl.
<p>The Linux Bowl was the final event. Two teams
of six developers were pitted against each other to answer
thirty questions about Linux and the Linux community. Questions
ranged from "What liquid should one drink between rounds of a
Finnish sauna?" (correct answer: beer) to "What version library
fixed a particular security hole?" to which Alan Cox gave a
(seemingly) ten minute answer. While some of the questions were
very obscure (even the moderator was unsure of the answer), most
of the time either the right answer (or a good facsimile) was
given.
<p>The show sponsors (after tallying up the attendence) reported that
958 people showed up, which could be the largest Linux-specific event
ever, of which 40% were from within North Carolina. Attendees came from
over 25 states, 4 Canadian provinces, and 10 countries, including Australia,
Korea and European countries.
<p>Finally, I would like to thank the members of the Atlanta Linux
Enthusiasts <a href="http://www.ale.org/">http://www.ale.org/</a> group who helped to staff the Linux
International booth. They were great and helped give me the freedom
to get out from behind the booth every once in a while, because
most importantly, Linux Expo was a chance to talk with the
vendors, the developers and other old and new friends on a
one-to-one, quality basis. Perhaps some things could be improved
for next year: A larger auditorium for the talks, more and
closer parking and less expensive food in the food court. But
certainly the southern hospitality and warmth of Red Hat Software
came through. I want to thank the sponsors for arranging a great event,
and I hope that next year's will be even larger and better.
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1997, Jon "maddog" Hall<BR>
Published in Issue 17 of the Linux Gazette, May 1997</H5></center>
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<center>
<h1>A Fresh Beginning: The Enlightenment Window Manager</h1>
<H4>By Larry Ayers,
<a href="mailto:layers@vax2.rainis.net">layers@vax2.rainis.net</a></H4>
</center>
<P> <HR> <P>
<center><h3>Introduction</h3></center>
<p>Most of the window-managers available for Linux these days can trace their
ancestry back to the original twm program, which may have been the first
widely used manager on unix systems. There is a good reason for this, as twm
pioneered many of the features taken for granted by users, such as movable,
resizable windows and a root-window applications menu. It's good, time-tested
code; why reinvent the wheel?
<p>Two programmers have recently done just that, from two perspectives as far
removed from each other as their respective geographical locations. Chris
Cannam, a British programmer, has taken the minimalist approach with his wm2
manager (which I wrote about in LG #14) and the new wm2 variant wmx, which I
discuss elsewhere in this issue.
<p>At the other extreme is the work of a young Australian programmer who likes
to be known as the Rasterman. Imagine asking the programmers responsible for
the games Quake or Duke Nukem 3D to write a window-manager; the result might
bear some resemblance to the fanciful program known as Enlightenment.
<p>I first encountered Enlightenment (what a name! it seems to carry the
implication that we users of fvwm et al are still crawling blindly through the
primordial ooze...) earlier this year, when a binary was available on the web.
I tried it briefly, but at the time I had a 486 machine; it ran slowly for me
and seemed to consume great gobs of memory. Recently the Rasterman
(his real name is Carsten Haitzler) has rewritten the application from scratch,
tightening it up and introducing a new shared lib which handles image loading
and rescaling. The memory consumption has been greatly reduced since the
initial release. At this point (beta release 4) there are no virtual desktops
or root-window menus, but the project looks promising and what there is of it
runs well for me.
<center><h3>Features and Appearance</h3></center>
<p>Enlightenment uses the <b>ppm</b> image format for both window details and
icons. An elaborate configuration file (called <i>windowstyles</i>) specifies
which image goes where. Each segment of the window border and detailing is a
separate <b>ppm</b> file. I haven't made any attempt to modify the default
configuration. It looks like it would take many hours to write a new one. Carsten
plans on eventually offering configurations which would emulate any of the
other window-managers.
<p>I get the impression from the Enlightenment web-page that the <b>ppm</b>
format is more efficient than others, especially on 16-32 bit displays. I
don't know how valid this is, but the window-manager <i>does</i> seem to do
quite a bit of image handling without consuming great amounts of memory.
<p>This window-manager automatically will load any sort of image format as a
root background image. At startup the appropriate netpbm utility is summoned
to transform the image to the <b>ppm</b> format. Naturally, you need
to have the netpbm graphics utility package installed for this to work.
<p>Here is a screenshot of a window under Enlightenment:<br>
<p>
<img alt="Enlightenment Window" src="./gx/ayers/enl.gif"><br>
<p> XV (with which I made the screenshot) couldn't figure out where the actual
window border was; can you blame it? I set the root-window background to be
the same color as this HTML-file background as a quick work-around.
<center><h3>Availability</h3></center>
<p>The Enlightenment web-site is at <a href=
"http://www.cse.unsw.edu.au/~s2154962/enlightenment/index.html">
http://www.cse.unsw.edu.au/~s2154962/enlightenment/index.html</a>.
The source for the latest version can be downloaded from the site; the latest
news about the application will also be there.
<center><h3>Closing Thoughts</h3></center>
<p>It will be interesting to see what eventually happens with Enlightenment,
though personally I'm satisfied with the window-managers I currently use. I
just like to see diversity in software for Linux. Fancy new window-borders
might seem to be a trivial matter but it is user-interface features such as
these which can attract new users, especially younger ones. I showed
Enlightenment to my sixteen-year-old son (an avid computer- game player) and
he was impressed. His comment was "It looks like a game interface!".
<p>Another factor is the simple human desire for novelty. Sometimes the same
old interface becomes boring -- you realize you aren't really even seeing it
anymore. A change in background and window-style can be refreshing. People
routinely change room interiors for these same reasons and, come to think of
it, I look at my computer screen quite a bit more than I do the walls!
<p>Keep in mind that the science-fiction Bladerunneresque appearance is just
the default. Enlightenment is a framework and could be configured in a
variety of ways, depending upon taste (and how much time you're willing to
spend!). Luckily (if you have patience), someone will eventually come up with
a configuration which will suit you. or at least be close. Interest seems to
be growing in this window-manager lately (judging by the volume of messages in
the mailing list) and it may yet evolve into a community-supported
window-manager, such as Fvwm2 or Afterstep. It's been released under the Gnu
license, but so far Carsten Haitzler is the sole developer.
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1997, Larry Ayers <BR>
Published in Issue 17 of the Linux Gazette, May 1997</H5></center>
<!--===================================================================-->
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<!--===================================================================-->
<center>
<H1>Visual Music: The Linux Port of Cthugha</h1>
<H4>By Larry Ayers,
<a href="mailto:layers@vax2.rainis.net">layers@vax2.rainis.net</a></H4>
</center>
<P> <hr> <P>
<center><h3>Introduction</h3></center>
<p>Around 1993 Kevin Burfitt, an Australian computer science student, began
developing a computer program which would transform recorded music into moving
colored patterns. Programs such as this had been in use for some time,
typically as an adjunct to a rock concert, i.e. part of the "light show".
This program was originally written for DOS, though before long it began to
acquire a trait common to software in the unix world: a multitude of options
and parameters.
<p>Kevin must be a fan of the early 20th-century horror writer
H.P. Lovecraft. How else to account for the distinctive appellation "Cthugha"
which he gave his program? In the Lovecraft stories Cthugha is the name given
to a horrific "elder god" which manifested itself to humans in the form of
shifting colored lights. (This doesn't sound too horrific, but Lovecraft
could make a loaf of bread seem sinister!)
<p>Cthugha has from the early days been available under the aegis of
the Gnu General Public License, making the source freely available. This
opened the door for many other programmers scattered throughout the world who
became involved with the project. Sound familiar? Ports of the
program are now available for the PowerMac, Win95 (in development), and of
course Linux. <a href="mailto: k3096e5@c210.edvz.uni-linz.ac.at">Harald
Deischinger</a> is responsible for the Linux port. He recently released a new
version (0.9) which is available from the following sites:<br>
<ul>
<li> <a href="ftp://sunsite.unc.edu/pub/Linux/apps/sound">Sunsite (may still
be in /pub/Linux/Incoming)</a>
<li><a href="ftp://ftp.afn.org/cthugha/linux">The main Cthugha site</a>
</ul>
<center><h3>What Cthugha Does</h3></center>
<p>The input to the program can be any audio source, such as a microphone, a
CDROM drive (though you must have the drive connected to your soundcard), or
even a sound file. Cthugha takes the digital audio information and, after
passing the data stream through any combination of filters, displays it to the
screen in real time. The keyboard is used to change the various parameters
either specifically or randomly. The simplest displays resemble the screen of
an oscilloscope being fed audio data (Cthugha has been called "an
oscilloscope on acid") but as more optional filters are added the display
becomes baroquely intricate. If too many filters are active the
resulting images can be chaotic, with little discernible relation to the sound
being processed.
<center><h3>Running Cthugha</h3></center>
<p>The Linux version of Cthugha is compiled into two executables: cthugha,
which is a console application (using Svgalib), and xcthugha, which runs
either in an X-window or as a full-screen X application using the new DGA
extensions. This last requires XFree86 3.2 or later. Xcthugha can also be
run as a screensaver; in former releases this was a separate executable.
<p>In this release the X11 version runs faster and smoother than in earlier
releases, but I still prefer the console version. It's the quickest and most
responsive of the three interfaces and (in my experience) the only usable
version on a machine less powerful than a mid-range Pentium.
<p>Running Cthugha reminds me of playing a musical instrument. The first
attempts aren't consistently pleasant, but with practice a measure of control
is gained. Orchestral or loud rock music can benefit from
low gain settings, which help to produce a non-chaotic display. The good sort of
recording to start with is music with few voices or tracks. A vocalist with
minimal accompaniment or solo instrumental music give good results
while you gain a feel for the program.
<p>Cthugha comes with several "translation tables"; these are
filters which map the display to various moving patterns, such as spirals or
the appearance of traveling through a starfield. I don't use them much, as it
seems to me they obscure the relationship between the music and the display.
The tables also tend to increase CPU usage. Try them and see what you think,
as they seem to be popular with other Cthugha users.
<p>The other filter categories are more useful. The "wave" filters control the
general shape of the sound waves. These run the gamut from basic oscilloscope
sine and square waves to angular lightning-like patterns or floating clusters
of fire-flies. The "flame" filters add to the waves trailing clouds of glory
(I've always wanted to use that phrase in a non-ironic sense!).
<p>Using a microphone as input is fun, especially if there are kids around.
Seeing your voice represented as billowing clouds of iridescent plasma is
novel, to say the least. Various musical instruments are interesting to try
as well; if one person plays the instrument while the other keys in parameters,
a combination which seems to reflect the character of the melody can often
be found. If you should happen upon a combination of settings which results
in a particularly pleasing screen just press the <b>a</b> key and those
settings are entered into your Cthugha initialization file.
<p>Another option is the Fast Fourier Transform, an algorithm which gives an
entirely different look to the sound; it's hard to describe, but FFT seems
more three-dimensional and subtle. The sampling rate should be reduced to
22000 hz. (from the default of 44000 hz.) since FFT adds one more level of
computation to the sound-translation process.
<p>Kevin Burfitt's decision to use the Fractint 256-color palette file as the
Cthugha palette file format was fortuitous. Over the years Fractint users
have come up with a multitude of palette files among which can be found
palettes to please anyone's taste. The Fractint fractal generator includes a
handy palette-file editor which can be used to create or modify palettes for
Cthugha. I'm not sure if the palette editor is included with Xfractint -- I
mostly use the DOS Fractint in a Dosemu console session.
<p>Here are a couple of screen-shots of xcthugha running in a 320x200
window:<br>
<hr>
<img src="./gx/ayers/cthugha3.gif" alt="Cthugha image #1">
<img src="./gx/ayers/cthugha4.gif" alt="Cthugha image #2">
<hr>
<p>These are snapshots, of course, and show little of the dynamic quality of
Cthugha reacting to the music. The above images, by the way,
are of an old recording of Sarah Vaughan singing with piano accompaniment.
<p><hr><p>
<!-- hhmts start -->
Last modified: Sun 27 Apr 1997
<!-- hhmts end -->
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1997, Larry Ayers<BR>
Published in Issue 17 of the Linux Gazette, May 1997</H5></center>
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<!--===================================================================-->
<center>
<H2>Updates and Corrections</H2>
<H4>By Larry Ayers,
<a href="mailto:layers@vax2.rainis.net">layers@vax2.rainis.net</a></H4>
</center>
<P> <HR>
<p>After I finish these Gazette articles and get them uploaded to SSC,
I can usually count on a URL changing or a newer version of a program being
released. Sometimes that very day! The Gazette readers are also quick to let
me know of any factual errors I've made. I've accumulated
several of these corrections and updates and shall present them here.
<hr>
<center><h3>GV</h3></center>
<p>Last month I wrote a short piece about GV, a new Postscript file viewer.
I received a letter from the maintainer of the Debian GV package:<br><pre>
Hello Larry!
I enjoyed reading your article, but there are two remarks I want to
make:
- Your screen capture is one of the one modified gv that works with
all Athena Widgets, including the standard one. These modifications
were made by me (although it wasn't very hard once I realized how
well Johannes separated the Xaw3d stuff from the rest).
It would have been better to have a screen capture using libXaw3d, as
that is the standard look and feel. The last statement about having
to have Xaw3d is not very convincing this way.
- There is a gv homepage now:
<a href="http://wwwthep.physik.uni-mainz.de/~plass/gv/">
http://wwwthep.physik.uni-mainz.de/~plass/gv/</a>
This page currently features gv version 3, which can no longer be
used without libXaw3d. The last version of gv supporting standard
Xaw was 2.9.4 which will soon be available on a debian archive site.
Version 3 is even better than version 2 with respect to look and feel
(one of the first really convincing applications using Xaw3d, IMO)
and an improved postscript scanner.
While I'm sure that it isn't possible to change/add to the article,
there could be a short notice in the next gazette.
Helmut
--
Helmut Geyer Helmut.Geyer@iwr.uni-heidelberg.de
public PGP key available : finger geyer@saturn.iwr.uni-heidelberg.de
</pre>
<hr>
<center><h3>FileRunner</h3></center>
<p>FileRunner has been updated several times since I reviewed it several
months ago. The latest version, 2.3, has improved FTP capabilities (including
the option of downloading files with a separate background process). I must
confess I'm addicted to this file-manager. Once you get the hang of it file
manipulation and directory traversals become so speedy that using it as
<b>root</b> can be risky! Check the <a
href="http://www.cd.chalmers.se/~hch/filerunner.html"> FileRunner WWW
site</a> for latest releases and news.
<p>Here's an example of a user-configured action-button for FileRunner, which
will mostly interest XEmacs users (though it could probably be adapted easily
for use with GNU Emacs). Create a file in the <b>~/.fr</b> directory named
<b>cmds</b>, then enter this text into it:<pre><code>
# This is an example of user-defined commands. This file should be named
# cmds and placed in your ~/.fr directory. It will then be read by
# FileRunner at startup. Versions of FileRunner prior to 2.3 need to have
#the file named .fr_cmds and placed directly in the home directory.
# This list should contain all user-defined commands formatted as:
# { { &lt;button-title&gt; &lt;procedure-name&gt; } {..} {..} }
set config(usercommands) {
{ XEmacs xemacs }
}
#
proc xemacs { filelist srcdir destdir } {
cd $srcdir
# set l {}
foreach f $filelist {
exec gnuclient -q $f
}
}
</code></pre>
<p>For this to work, you must have <i>gnuserv</i> running; this can be started
from your <i>~/.xemacs-options</i> file by including the line<br>
<code>(gnuserv-start)</code><br> in the file. What this button does is send
the files you've selected to an already-running XEmacs process (I usually have
one running in a different virtual desktop than the one FileRunner is using).
XEmacs will then open up a new frame in your current desktop with the file(s)
displayed in it. This is handy for browsing source code.
<center><h3>wm2 and wmx </h3></center>
<p>In LG #14 I wrote about the minimalist window-manager wm2, written by
British programmer Chris Cannam. Since then wm2 has spawned a variant, known
as wmx. Evidently Mr. Cannam felt that spartan wm2 was becoming decadently
featureful. Wm2 was stripped down to the bare minimum; no more
frame-background pixmaps,etc. Wmx is just wm2 with the afore-mentioned
pixmaps and a basic virtual-desktop utility. It has one more feature which I
thought was very cleverly designed: if you click the middle mouse button on
the desktop an application menu appears. Unlike most window-managers, the
entries on the menu are a snap to set up. Simply create a subdirectory
stemming from your home directory called <i>.wmx</i> and symlink executables
to it. This can be even done while wmx is running. Whatever appears in
<i>~/.wmx</i> will appear in the menu. The menu can be configured with a
transparent background so that it has a very stylish and spare appearance. As
with wm2 the configuration can only be changed by recompiling, but this can be
done very quickly as the source is not large or complex. Source for either
wm2 or wmx can be obtained from
<a href="http://www.netcomuk.co.uk/~cannam/wm2.html">
the wm2 web-site.</a>
<center><h3>Afterstep</h3></center>
<p>A reader pointed out an error in my description of the Afterstep
window-manager in LG #14. Rather than being based on Fvwm2 code, Afterstep is
based on Fvwm version 1 code. Incidentally, pre-release 6 has been released
and is well worth a trial. Several bugs have been fixed but the improved
documentation alone makes it worth the download.
<center><h3>Xvile</h3></center>
<p>Lately it seems that a fad is sweeping the insular world of vi-like
editors. First the X versions of Elvis and Vim appeared with
pull-down menus; now it appears that Xvile will soon have a menubar as well.
If <b>a:</b> you like vile/xvile and <b>b:</b> you have the Motif libs
installed, you may want to take a look at the patches for vile 7.00 available
from the <a href="ftp://ftp.clark.net/pub/dickey/vile/patches">Vile ftp site.</a>
The patches A through G need to be applied to the vile 7.0 source. It looks
like the menu items will be fairly easy to set up, as they make use of the
standard vile functions. An implementation for non-Motif X setups is
planned.
<p>I have mixed feelings about GUI conveniences such as menus in a vi editor.
One of the appealing traits of these editors is the lack of such visible
features combined with a wide array of invisible and powerful commands.
Little overhead but great power and speed. If you have to reach for the mouse
and select a menu-item, why not use Nedit (for example) which is designed as a
mouse-oriented editor? On the other hand, how many users have had an
unpleasant first-time experience with vi and rejected it forever? At
least the menubar will have a "quit-ZZ" item, allowing a novice to end a
first session without having to desperately flee to another virtual console
and kill the vi process from afar!
<center><h3>TkDesk</h3></center>
<p>The latest version of this versatile desktop/file manager can be found at
<a href="http://sun1.rrzn-user.uni-hannover.de/~zzhibol/tkdesk">the TkDesk home site.</a> Version 1.0b4 has been released and many
minor bugs have been fixed. There are three patches available on the web-site
which should be applied by users of the program. Two of them are changes to
<i>*.tcl</i> files, whereas the third is a c-source-level change which
requires recompilation. Debian users can instead install a patched TkDesk
package which is available from the <i>/bo/binary-i386/x11</i> directory of
ftp.debian.org and its mirrors.
<center><h3>The Midnight Commander</h3></center>
<p>For the past several months a beta development cycle has been underway in
preparation for the release of mc-3.1.5. The recent releases (the latest as
of this writing is patchlevel 25) have been very stable and usable. If you
use the Midnight Commander frequently it might be worth your while to try the
new version, as many improvements have been made.
<p>An internal editor has been incorporated into mc, though you still can
change the settings and use any console-mode external editor. The FTP
capabilities of mc have been augmented and the Tk version has made great
strides and needs just a few more features to be the equal of the
classic console version. mc now has the ability to dive into <i>*.rpm</i> and
<i>*.deb</i> files in the same manner it has been able to do with <i>*.tgz</i>
and <i>*.zip</i> files, allowing you to inspect their contents without
unpacking the archives.
<p>It's only available in source form, but it comes with a good configure script
and compiles easily here. The source is available from
<a href="ftp://ftp.nuclecu.unam.mx/Midnight/devel">the mc home site</a>.
<center><h3>XEmacs Update</h3></center>
<p>Last month I wrote about the release of XEmacs 19.15. The XEmacs team
didn't stop and rest on their laurels (probably because some unexpected
problems showed up after the release!); beta releases of XEmacs 20.1 began
showing up about twice a week at <b>ftp.xemacs.org</b>. It looked as if
version 20.1 was about to be released, but for some reason the release was
cancelled and they moved on to betas of 20.2. I'm running beta 2 now,
and have found that several small problems with 19.15 have been fixed. The
Customization utility works quite a bit better now, for one. When 20.2 is
released I would recommend obtaining it, as it looks like it will be an
improvement over 19.15. Another approach if you've already installed 19.15 is
to visit <a href="http://www.xemacs.org/xemacs-19.15-patches/patch-page.html">
the XEmacs patches page</a>, which offers patches to upgrade 19.15 to
patchlevel 2. The problems dealt with are described on the page; if the
patches concern modes or utilities you never use, there's no point in applying them.
<p><hr><p>
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1997, Larry Ayers <BR>
Published in Issue 17 of the Linux Gazette, May 1997</H5></center>
<!--===================================================================-->
<P> <hr> <P>
<A HREF="./index.html"><IMG ALIGN=BOTTOM SRC="../gx/indexnew.gif"
ALT="[ TABLE OF CONTENTS ]"></A>
<A HREF="../index.html"><IMG ALIGN=BOTTOM SRC="../gx/homenew.gif"
ALT="[ FRONT PAGE ]"></A>
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<P> <hr> <P>
<H4>
&quot;Linux Gazette...<I>making Linux just a little more fun!</I>&quot;
</H4>
<P> <HR> <P>
<!--===================================================================-->
<center>
<H2>Slackware</H2>
<H4>By Sean Dreilinger,
<a href="mailto:sean@kensho.com">sean@kensho.com</a></H4>
</center>
<HR>
<p><hr><p>
<H3>Contents:</H3>
<ul>
<li><a href="./slackware.html#slackware">Slackware Is Not For You (Or Maybe
It Is)</a>
<li><a href="./slackware.html#history">A Quick History</a>
<li><a href="./slackware.html#why">Why, Then?</a>
<li><a href="./slackware.html#planning">Planning</a>
<li><a href="./slackware.html#thinking">Thinking Through Storage and File
Systems</a>
<li><a href="./slackware.html#upgrade">Upgrade? Think Twice!</a>
<li><a href="./slackware.html#boot">Boot Disks: Always A Good Thing</a>
<li><a href="./slackware.html#slack1">Slackware Setup Worksheet</a>
<li><a href="./slackware.html#slack2">Slackware Setup Program</a>
<li><a href="./slackware.html#trouble">Troubleshooting</a>
<li><a href="./slackware.html#basking">Basking In The Afterglow</a>
<li><a href="./slackware.html#install">Install and Test</a>
<li><a href="./slackware.html#secure">Secure the System</a>
<li><a href="./slackware.html#backup">Back Up</a>
</ul>
<a name="slackware"></a>
<h3>Slackware Is Not For You (Or Maybe It Is)</h3>
<p>Welcome to the Slackware distribution of Linux! This chapter aims
to help the new Linux user or administrator evaluate Slackware,
plan a Slackware system, and install Slackware Linux. In it you'll
find an emphasis on careful planning rather than rushing into
an impetuous installation. A special worksheet is included to
help you "get it right the first time", which I hope will be especially
useful to overworked Unix administrators in busy environments.
<p>Whether or not to choose Slackware as the flavor of Linux you
will use is a serious consideration. It may seem like a trivial
decision now, but Linux boxes have a way of taking on more and
more responsibility in organizational computing environments.
Plenty of Linux <I>experiments</I> have evolved in their first
year to become mission-critical machines serving many more users
and purposes than originally intended. Slackware is one of the
most widely used distributions of Linux. When it comes to finding
the newest, easiest, or most carefully planned distribution of
Linux, Slackware may be "none of the above". Some background on
the life and times of Slackware put things into perspective.
<a name="history"></a>
<h3>A Quick History</h3>
<p>In 1993, SLS created one of the first organized distributions
of Linux. Although it was a great start, the SLS distribution
had many shortcomings (it didn't exactly work, for starters).
Slackware, a godsend from Patrick Volkerding, solved most of these
issues, was mirrored via FTP and pressed onto CD-ROMs the worldwide,
and quickly became the most widely used flavor of Linux. For a
while, Slackware was the only full-featured Linux solution.
Other Linux distribution maintainers, both commercial and nonprofit,
have gradually developed distributions that are also well worth
your consideration.
<p>According to statistics maintained by the Linux Counter Project,
Slackware inhabits about 69% of all machines that run Linux. Slackware
is typically obtained via FTP or CD-ROM and installed on a 486-class
computer running at 66Mhz with about 16 MB of memory and 1050
MB of storage. More information about Linux use and the Linux
Counter Project is available on the World Wide Web.
<a href="http://domen.uninett.no/\~hta/linux/counter.html">http://domen.uninett.no/\~hta/linux/counter.html</a><br>
<p>By January 1994, Slackware had achieved such widespread use that
it earned a popular notoriety normally reserved for rock stars
and cult leaders. Gossip spread through the Usenet suggesting
that the entire Slackware project was the work of witches and
devil-worshippers!
"Linux, the free OS....except for your SOUL! MOUHAHAHAHA!"
<p>
From: <a href="mailto:cajho@uno.edu">cajho@uno.edu</a><br>
Date: 7 Jan 1994 15:48:07 GMT<br>
<p>Jokes alluding to RFC 666, demonic daemons, and speculation that
Pat Volkerding was actually L. Ron Hubbard in disguise were rampant
in the threads that followed. The whole amusing incident probably
helped Slackware gain some market share:
<p>I LOVE THIS!!
<p>I was browsing here to figure which version of Linux to install,
but after this, I think that I hve no choice but to install Slackware
now.
<p>
From: <a href="mailto:dsith@phantom.com">David Devejian</a><br>
Date: 10 Jan 1994 04:57:41 GMT<br>
<p>All folklore and kidding aside, Slackware is a wise and powerful
choice for your adventures in Linux, whether you are a hobbyist,
student, hacker, or system administrator in the making.
<a name="why"></a>
<h3>Why, Then?</h3>
<p>If you are a system administrator, you may already be dealing
with one or more key servers running Slackware. Unless you have
time to experiment at work, sticking to the tried-and-true distribution
may be the easiest way to go. If you expect to get help from Unix
literate friends and colleagues, better make sure they're running
something compatible-odds are they're running Slackware. Its shortcomings
are widely acknowledged, for the most part discovered, documented
and patched whenever possible. You can put together a Slackware
box, close the known security holes, and install some complementary
tools from the other Linux distributions to create an excellent
Unix server or desktop workstation, all in about half a day.
<h3>Slackware Pros and Cons</h3>
<p>
<table cellpadding=10>
<tr>
<td valign=top>Slackware is old</td> <td>It's mature, widely available,
and the most widely installed
Linux distribution <br></td>
</tr>
<tr>
<td valign=top>Slackware lacks sexy administrative tools a la RedHat</td>
<td valign=top>You're free to add
other distributions such as
the RedHat package manager <br></td>
</tr>
<tr>
<td valign=top>Slackware includes bundled security holes</td>
<td valign=top>We know what some of the
vulnerabilities are and
volunteers have posted fixes <br></td>
</tr>
<tr>
<td valign=top>
Donald Knuth complained about the fonts</td>
<td valign=top>Patrick Volkerding fixed the
fonts <br></td></tr>
<tr>
<td valign=top>Linus Torvalds uses another distribution</td> <td>Oh well <br></td>
</tr>
<tr>
<td valign=top>Slackware is assembled by Devil Worshippers</td>
<td valign=top>Satanist crackers (not SATAN
itself) will avoid your box <br></td>
</tr>
<tr>
<td valign=top>Slackware is no longer</td>
<td valign=top>This is a myth, Slackware is
developed actively maintained, sans
marketing hype <br></td>
</tr>
<tr>
<td valign=top>Slackware is not supported by a commercial vendor or sanctionaed user
group</td>
<td valign=top>Linux support is available
along with consultants, explained further
in the section on Commercial
Support <br></td>
</tr>
<tr>
<td valign=top>Slackware is not created by a committee or development team</td>
<td valign=top>Good. A system designed by one
accountable individual is
cohesive<br></td>
</tr>
</table>
<p>If you are still undecided whether Slackware is the tastiest flavor
of Linux for you, have a look at the "Buyer's Guide"
published in the <I>Linux Journal</I>, which gives a thorough
comparison and evaluation of each major distribution. For a straightforward
listing of Linux flavors, have a look at the Linux Distribution HOWTO
on the Internet:<br>
<a href="http://sunsite.unc.edu/LDP/HOWTO/Distribution-HOWTO.html">http://sunsite.unc.edu/LDP/HOWTO/Distribution-HOWTO.html</a><br>
<a name="planning"></a>
<h3>Planning</h3>
<p>Nine tenths of wisdom is timing. The right time to set up Slackware
is <I> after</I>you've carefully planned the installation <I>and
</I>alternatives in the unfortunate event of a problem. A well-planned
installation of Slackware will repay itself many times over in
the future, when the natural process of Linux evolution leads
you to add disk space, install a newer Slackware release, or jettison
any old, inferior operating systems that may linger on your drives.
<p>Like Unix, Slackware Linux tends to grow like a virus. If you
succeed in getting one Slackware box up and running, you're likely
to start infecting other computers that belong to your friends,
family, and coworkers. When this happens, you'll be grateful that
you at least took the time to think through this first setup-and
so will they!
<p>This section will help you decide...
<ul>
<li>if you've got what it takes (of course you do!)
<li>whether your computer hardware is ready to run Slackware Linux
<li>where and how to get Slackware Linux
<li>how to best arrange disks and file systems to protect your
work
<li>not to upgrade an older version of Slackware
<li>which packages of the distribution you want and need
<li>how you will handle installation problems (however unlikely)
</ul>
<h3>Literacy Required</h3>
<p>Linux is a powerful operating system, and with power comes responsibility.
Like Linux, the Slackware release treats you with the respect
you deserve as an intelligent human being. If you elect to wipe
out a few hard drives with a misplaced punctuation mark, so be
it. There are graceful and intelligent front-ends to Linux that
allow the average end-user to get lots of productive work done
without ever delving into the cryptic subtleties of Unix setup
and administration. But there's no such luck for you, the appointed
installation guru. If you're going to install Slackware, be forewarned
that you should know your IRQs from your RS232s and your SCSIs
from your IDEs.
<h3>Hardware Compatibility</h3>
<p>This is an essential element for planning any Linux installation. The only
Slackware-specific hardware issue is this: you must confirm that
the particular version (vintage, release) distribution of Slackware
you'll be installing from provides a <I>kernel and drivers to
support your hardware</I>. You're in great shape with just about
any IBM-compatible personal computer with an Intel CPU older than
the date on your Slackware distribution but younger than 1992
(built after 1992). If you have a bleeding-edge machine, you may
need to download a newer boot disk that includes an updated kernel
and drivers.
<p>For the latest information on <I>it general</I> Linux hardware compatibility,
check the Linux Hardware Compatibility HOWTO document on the World
Wide Web:<br>
<a href="http://sunsite.unc.edu/LDP/HOWTO/Hardware-HOWTO.html">http://sunsite.unc.edu/LDP/HOWTO/Hardware-HOWTO.html</a><br>
<p>To check for up-to-the minute Slackware news, such as which boot
kernels are available, you can look in this directory of the Slackware
home ftp site, ftp.cdrom.com:<br>
<a href="ftp://ftp.cdrom.com/pub/linux/slackware/patches/">ftp://ftp.cdrom.com/pub/linux/slackware/patches/</a><br>
<a name="thinking"></a>
<h3>Thinking Through Storage And File Systems</h3>
<p>Careful planning of file systems and the storage media upon which
they reside can spare you hours of painful juggling at a later
date. In particular, putting all of your custom administration
files, user homes, and local software onto dedicated partitions
or disks will allow you to upgrade Slackware on the root partition
with minimal disruption to your improvements to the system.
<h3>Multiple Operating Systems On One Hard Drive</h3>
<p>A typical personal computer has one fixed disk drive. If you're
a hobbyist or power user, you may already have installed more
than one Operating System on that drive. For example, your computer
may have shipped running MS-DOS or Windows 95 as a pre-loaded
operating system, after which you added another operating system
such as OS/2, NeXTstep, Geoworks, or Linux. To run multiple operating
systems from one drive, the disk is divided into separate areas
known as partitions. Each partition may contain a different operating
system. Once you've installed a second OS, you also need to install
a small program called a boot manager or OS loader that runs at
system startup time and offers you a choice of all the installed
operating systems.
<p>If you're adding Linux to a computer running a lesser OS, you
may elect to keep the old operating system around for kicks. Take
a look at the Linux Loader (LILO), a high-powered boot manager
that comes free with Slackware. The latest distribution of LILO
and its documentation are available via FTP from this URL:<br>
<a href="ftp://lrcftp.epfl.ch/pub/linux/local/lilo/">ftp://lrcftp.epfl.ch/pub/linus/local/lilo/</a><br>
An overview of LILO and how you can use it are easily gleaned
from the LILO Mini-HOWTO:<br>
<a href="http://sunsite.unc.edu/LDP/HOWTO/mini/LILO">http://sunsite.unc.edu/LDP/HOWTO/mini/LILO/</a><br>
<h3>Designing a File System To Use Multiple Partitions</h3>
<p>In a simple world, you can set up Linux to run on a single disk
partition (or maybe two-one for swap). In a real-world, multi-user
Unix system, a single-drive file system setup creates unnecessary
risks and hassles you can avoid by distributing the file system
across multiple partitions. It's all the same to Unix, which views
the file system as a continuum of available space comprised of
all the disks and partitions "mounted" into various locations
on the file tree.
<p>If you create a Slackware setup on only one drive partition, you
effectively put all of your eggs in one basket-one user may receive
an abundance of e-mail and overload the <tt>/var/mail</tt>
file system, another might store enormous files in their home area,
etc. As with many Unix quandaries, you have a choice of solutions
to control file system use, including quotas and user limits. Distributing
your Unix file system across multiple partitions and disks has
an extra benefit for Slackware users-it allows you to upgrade
the Slackware installation with a minimum of pain.
<p>The Linux file system standard puts the personal space of each
user into a subdirectory of <tt>/home</tt>. The user Linus
would typically have a home under <tt>/home/linus</tt>, the
user Patricia under <tt>/home/patricia</tt>, and so on. An
easy way to protect this file system during future upgrades is
to mount <tt>/home</tt> on a separate disk or partition. Same goes for
custom programs and resources you add to the off-the-shelf version
of Slackware-plan to put these on a separate disk mounted to <tt>/usr/local</tt>
and you'll have much less grief when it comes time to upgrade.
"Where things go"---or where they try to go unless you dictate otherwise---
in a Slackware box is determined by a standard file system layout,
called the <I>Linux File system Hierarchy Standard</I>. Read all
about it URL:<br>
<a href="http://www.pathname.com/fhs/">http://www.pathname.com/fhs/</a><br>
<h3>Designing a File System To Use Multiple Hard Drives</h3>
<p>In some settings, Linux boxes are assembled from leftover parts-"worthless"
386 and 486 motherboards, old grayscale monitors, and discarded
hard drives. You may need to link together several ancient 40MB
hard drives to come up with enough space to install Slackware.
In other environments using Linux, there are so many users and
such large development projects that several of the biggest, state-of-the-art
drives or drive arrays must be integrated to provide enough space.
<p>You can install Slackware onto more than one disk at once by
designating individual disks to hold specific parts of the Slackware
installation (just like using multiple partitions), creating a
logically continuous and unified file system.
<p>For an informed second opinion on partitioning, swap space setup,
fragmentation and inode size consult Kristian Koehntopp's <I>Partitions</I>
Mini-HOWTO via Internet URL:<br>
<a href="http://sunsite.unc.edu/mdw/HOWTO/mini/Partition/">http://sunsite.unc.edu/mdw/HOWTO/mini/Partition/</a><br>
<a name="upgrade"></a>
<h3>Upgrade? Think Twice!</h3>
<p>24-Aug-95 NOTE: Trying to upgrade to ELF Slackware from a.out
Slackware will undoubtedly cause you all kinds of
problems. Don't do it.
<p><b>Patrick Volkerding</b>
<p>One thing we don't hear too often with Slackware is the U-word.
Slackware's setup program is designed to put a fresh operating
system onto empty hard disks or empty disk partitions. Installing
on top of a previous Slackware installation can erase your custom
applications and cause compatibility problems between updated
applications and older files on the same system. When Slackware
was first put together, everyone was a first-time Linux user,
and the system was always experimental-reinstalling the entire
operating system and applications was the norm in a developmental
system. Today, many institutions and businesses now run mission-critical
applications on Slackware Linux. In such environment, a simple
reboot is a planned activity and taking down the system and overwriting
all the user files or custom applications is absolutely unacceptable.
<p>So, if you cracked open these pages to plot an upgrade, better
think twice. If you're planning a first-time Slackware installation,
there are a few decisions you can make now that will ease upgrading
in the future:
<ul>
<li>assign <tt>/usr/local</tt> to be mounted from its own
separate drive or partition
<li>build and install all of your organization's custom applications
under the <tt>/usr/local</tt> area of the file system
<li>assign <tt>/home</tt> to be mounted from its own separate
drive or partition
<li>make sure all user "homes" are added under the <tt>/home</tt>
area of the file system
</ul>
<p>Teaching you how to finagle a Slackware upgrade is beyond the
scope of this chapter, but it is workable if you are an experienced
Unix administrator and you've taken the precautions above. There
is an Internet resource that claims to analyze your distribution
and bring it up to date across the Internet, you might want to
have a look at this URL if you're facing an upgrade situation:<br>
<a href="ftp://ftp.wsc.com/pub/freeware/linux/update.linux/">ftp://ftp.wsc.com/pub/freeware/linux/update.linux/</a><br>
<p>Or read, weep, and learn from the upgrade expertise of Greg Louis
in his mini HOWTO document: <I>Upgrading Your Linux Distribution</I>,
available where finer LDP publications are mirrored:<br>
<a href="http://sunsite.unc.edu/LDP/">http://sunsite.unc.edu/LDP/</a>
<h3>Select An Installation Method</h3>
<p>Slackware can be installed from a variety of media and network
sources to fit your needs and budget. Every installation method
will require you to have at least three floppy diskettes available
to get started.
<h3>CD-ROM</h3>
<p>Installation from CD-ROM is fast, popular, and convenient. Although
someone has to break down and pay for the initial purchase of
a CD-ROM, sharing CD's is <I>encouraged</I>. Because Linux and
the Slackware distribution are copylefted, you may make as many
copies as you like. CD-ROM installation is also a bit better practice
in terms of netiquette, since you're not hogging bandwidth for
an all-day FTP transfer. Finally, you may be grateful for the
extra utilities and documentation that accompany the CD-ROM, especially
if you run into installation hassles or need to add components
in the future.
<h3>Party!</h3>
<p>If you're a hobbyist (or want to watch a few dozen Slackware installs
before taking on the task at work), see if there is a LUG (Linux
User Group) in your area that sponsors install parties. Imagine
a roomful of generous and knowledgeable hackers uniting to share
CD-ROMs and expertise with other enthusiasts.
<p><b>FTP</b>
<p>According to the Linux Counter Project, FTP is still the most
popular way to obtain Linux by a narrow margin. Once you transfer
Slackware from the closest possible FTP mirror, you'll still need
to put the Slackware 'disk sets' onto installation media such
as a hard drive partition or laboriously copy them onto 50-odd
floppy diskettes.
<p><b>NFS</b>
<p>In a networked environment, it is possible to install Slackware
on a shared file system and allow everyone on the Local net to
attach to this shared location and install. If you have the technical
know-how or a geeked out system administrator who is Linux-literate,
this is a great way to go. The initial distribution of Slackware
can be added to the network via CD-ROM, FTP, Loading floppies,
tape, or even via a remote NFS share across the Internet! For
details on such a remote share, see these URLs:
<ul>
<li><a href="http://sunsite.doc.ic.ac.uk/sunsite/access/nfs.html">http://sunsite.doc.ic.ac.uk/sunsite/access/nfs.html</a>
<li><a href="ftp://ftp.cdrom.com/pub/linux/slackware/MIRRORS.TXT">ftp://ftp.cdrom.com/pub/linux/slackware/MIRRORS.TXT</a>
<li><a href="http://www.cs.us.es/archive/nfs.html">http://www.cs.us.es/archive/nfs.html</a>
</ul>
<p><b>Floppy</b>
<p>It's time consuming, but it works-you can buy or create the pile
of floppies needed to install Slackware and then feed them into
your box one-by-one when prompted. Slackware 'disk sets' are actually
designed and arranged to fit floppy diskettes. If you happen to
have a huge stack of recycled high-density floppy diskettes at
your disposal, this can be the most economical way to go.
<p><b>Hard Disk</b>
<p>This is the way to do it if you've transferred the Slackware distribution
across the Internet via FTP-you'll escape the floppy trap by merely
creating boot, root, and rescue diskettes. It requires you to
have an extra disk or disk partition with extra space to hold
the Slackware files during installation (you can erase them afterwards).
Installation from the hard drive is also a workaround if you bought
the CD but your CD-ROM drive is not supported by any of the Linux
kernels that come with the Slackware CD. You can use your present
operating system to transfer the Slackware files onto spare hard
disk space, then boot into the Slackware installation.
<p><b>Tape</b>
<p>Still experimental as of this writing, tape offers a great compromise
of speed and economy when installing Slackware-worth considering
if a friend with compatible tape drive can dupe a CD or FTP archive
for you. Get the latest details from the TAPE section of the INSTALL.TXT
file that accompanies your Slackware distribution.
<a name="boot"></a>
<h3>Boot Disks: Always a Good Thing</h3>
<p>Even if you're gifted with a direct T-3 Internet connection that
allows you to suck up a new distribution of Slackware right off
the 'net, you'll be wise to start by building the two Slackware
setup disks (boot and root) before proceeding. In the event of
an unfortunate accident (power outage, feline friends traversing
the keyboard, or even human error), these two little disks, in
the hands of an experienced Unix hacker, may be able to revive
your system or at least rescue your personal files.
<h3>Prepare To Be Questioned (There Will Be a Quiz...)</h3>
<p>During the installation, must choose which disk sets (Slackware
lingo for collections of software) and individual programs to
install. You can usually just accept the default recommendation
of whether or not a package is worth having. A few setup decisions
are <I>crucial</I>. Mid-installation is no time to decide you
want to boot back into OS/2 and look up what kind of graphics
chip your video card uses, which network card you've got in there,
or whether you'll be needing a SCSI or an IDE kernel to get started.
<h3>Contingency Plan: Food For Thought</h3>
<p>I've often blurted out to a supervisor, "Oh sure, I can have
it up and running in a few hours." Famous last words.
If anyone else has a stake in the Slackware computer's health,
you owe it to them and yourself to think through a less-than-perfect
installation attempt:
<ol>
<li>What's your plan in the unfortunate event that Slackware Linux
doesn't run perfectly on your system?
<li>Do you have the necessary tools and know-how to revert to
your previous operating system?
<li>Do you have a backup of your old system on-hand, and do you
have experience restoring entire systems?
<li>Is this a shared computer? Will people be coming into work
on Monday expecting to log in to the system you just hosed?
<li>Where is the closest Unix expert with Slackware Linux expertise?
Can you call on them to help you in the event of a problem setting
up or upgrading a critical Slackware system?
</ol>
<a name="slack1"></a>
<h3>Slackware Setup Worksheet</h3>
<p>After the files are all copied, Slackware can go on to do most
of the system and network configuration, if you're ready. To help
you plan your decisions, Section 3 consists of a worksheet derived
from the text-based Slackware setup program. You can use this
worksheet to record answers in advance (while your computer is
still working!), so you'll be ready with the necessary details-partitions,
IP addresses, modem and mouse IRQs, host and domain names, and
others that you're required to provide during setup.
<ol>
<li><B>Keyboard:</B> Slackware setup will
want to know if you need to
remap your keyboard to something other
than a standard USA 101 key layout? <I>Yes or No</I>.
<li><B>Swap Configuration:</B>Do you have one or more
partitions prepared as type 82 (Linux Swap)? <I>Yes or No</I>.
<li>Do you want setup to use mkswap on your swap
partitions? Most likely "yes",
unless you have less than 4MB of RAM and have already done this
to help setup work better. <I>Yes or No</I>.
<li><B>Prepare Main Linux Partition:</B> Setup will list any
partitions marked as type 83 (Linux Native) and ask
which one to use for the root (/) of the Linux
file system. Use a format like
<tt>/dev/hda3</tt> or whatever the device name is. <I>Yes or No</I>.
<p>Last chance to back out! When using the install from
scratch option,
you must install to a blank partition. If you have not
already formatted it manually, then you must format it
when prompted. Enter <tt>I</tt> to install from scratch, or
<tt>a</tt> to add software to your existing system.
<li>(Re)format the main Linux partition. Would you like
to format this partition? <I>Yes or No</I>.
<p>Ext2fs defaults to one inode per 4096 bytes of drive
space. If you're going to have many small files on
your drive, you may need more inodes (one is used
for each file entry). You can change the density to
one inode per 2048 bytes, or even per 1024 bytes.
Enter <tt>2048</tt> or <tt>1024</tt>, or just hit <tt>Enter</tt> to accept
the default of 4096. 4096, 2048, or 1024.
<li><B>Prepare Additional Linux Partitions:</B> You can mount
some other partitions for <tt>/usr</tt> or <tt>/usr/X11</tt> or
whatever (<tt>/tmp</tt>---you name it). Would you like to use
some of the other Linux partitions to mount some of
your directories? <I>Yes or No</I>.
<p>These are your Linux partitions (<I>partition list displayed</I>).
These partitions are already in use
(<I>partition list displayed</I>). Enter the
partition you would like to use, or type <tt>q</tt> to quit
adding new partitions. Use a format such as:
<tt>/dev/hda3</tt> or whatever the device name is.
<I>Partition name or <tt>quit</tt></I>
<li>Would you like to format this
partition? Yes, No, or Check Sections, too</I>
<li>Now this new partition must be mounted somewhere in
your new directory tree. For example, if you want to
put it under <tt>/usr/X11R6</tt>, then respond: <tt>/usr/X11R6</tt>
Where would you like to mount this new partition?
<I>Mount point</I>
<li>Would you like to mount some more additional
partitions? <I>Yes or No</I>.
<p><B>DOS and OS/2 Partition Setup:</B> The following DOS FAT
or OS/2 HPFS partitions were found: (<I>partition list displayed</I>).
<li>Would you like to set up some of these
partitions to be visible from Linux? <I>Yes or No</I>.
<li>Please enter the partition you would like to access
from Linux, or type <tt>q</tt> to quit adding new
partitions. Use a format such as: <tt>/dev/hda3</tt> or
whatever the device name is.
<I>Partition name or Quit</I>
<li>Now this new partition must be mounted somewhere in
your directory tree. Please enter the directory
under which you would like to put it. for instance,
you might want to reply <tt>/dosc</tt>, <tt>/dosd</tt>, or something
like that. Where would you like to mount this partition?
<I>Mount point</I>
<li><B>Source Media Selection:</B>
<ol>
<li>Install from a hard drive partition.
<li>Install from floppy disks.
<li>Install via NFS.
<li>Install from a pre-mounted directory.
<li>Install from CD-ROM.
</ol>
<I>1, 2, 3, 4, or 5</I>
<li><B>Install from a hard drive partition:</B> To install
directly from the hard disk you must have a
partition with a directory containing the Slackware
distribution such that each disk other than the boot
disk is contained in a subdirectory. For example, if
the distribution is in <tt>/stuff/slack</tt>, then you need to have
directories named <tt>/stuff/slack/a1</tt>,
<tt>/stuff/slack/a2</tt>, and so on, each containing the
files that would be on that disk. You may install
from DOS, HPFS, or Linux partitions. Enter the
partition where the Slackware sources can be found,
or <tt>p</tt> to see a partition list.
<I>Partition name or Partition list</I>
<li>What directory on this partition can the Slackware
sources be found. In the example above, this would
be: <tt>/stuff/slack</tt>. What directory are the Slackware
sources in?
<I>Directory name</I>
<li>What type of file system does your Slackware source
partition contain?
<ol>
<li>FAT (MS-DOS, DR-DOS, OS/2)
<li>Linux Second Extended File System
<li>Linux Xiafs
<li>Linux MINIX
<li>OS/2 HPFS
</ol>
<I>1, 2, 3, 4, or 5</I>
<li><B>Install from a pre-mounted directory:</B> OK, we will
install from a directory that is currently mounted.
This can be mounted normally or through NFS. You
need to specify the name of the directory that
contains the subdirectories for each source disk.
Which directory would you like to install from?
<I>Directory name</I>
<li><B>Install from floppy disks:</B> The base Slackware series
(A) can be installed from 1.2M or 1.44M media. Most
of the other disks will not fit on 1.2M media, but
can be downloaded to your hard drive and installed
from there later. Which drive would you like to
install from (1/2/3/4)?
<ol>
<li><tt>/dev/fd0u1440</tt> (1.44M drive a:)
<li><tt>/dev/fd1u1440</tt> (1.44M drive b:)
<li><tt>/dev/fd0h1200</tt> (1.2M drive a:)
<li><tt>/dev/fd1h1200</tt> (1.2M drive b:)
</ol>
<I>1, 2, 3, or 4</I>
<li><B>Install via NFS:</B> You're running off the hard drive
file system. Is this machine currently running on the
network you plan to install from? If so, we won't
try to reconfigure your ethernet card. Are you
up-and-running on the network? Yes or No.
<li>You will need to enter the IP address you wish to
assign to this machine. Example: 111.112.113.114.
What is your IP address? <I>IP address</I>
<li>Now we need to know your netmask. Typically this
will be 255.255.255.0. What is your netmask?
<I>IP address</I>
<li>Do you have a gateway? <I>Yes or No</I>.
<li>What is your gateway address?
<I>IP address</I>
<p>Good! We're all set on the local end, but now we
need to know where to find the software packages to
install. First, we need the IP address of the
machine where the Slackware sources are stored.
Since you're already running on the network, you
should be able to use the hostname instead of an IP
address if you wish.
<li>What is the IP address of your
NFS server?
<I>IP address</I>
<p>There must be a directory on the server with the
Slackware sources for each disk in subdirectories
beneath it. Setup needs to know the name of the
directory on your server that contains the disk
subdirectories. For example, if your A3 disk is
found at <tt>/slackware/a3</tt>, then you would respond:
<tt>/slackware</tt>.
<li>What is the Slackware source directory?
<I>Directory name</I>
<li><B>Install from CD-ROM:</B> What type of CD-ROM drive do you have?
<ol>
<li>Works with most ATAPI/IDE CD drives <tt>/dev/hd*</tt>
<li>SCSI <tt>/dev/scd0</tt> or <tt>/dev/scd1</tt>
<li>Sony CDU31A/CDU33A <tt>/dev/sonycd</tt>
<li>Sony 531/535 <tt>/dev/cdu535</tt>
<li>Mitsumi, proprietary interface---not IDE <tt>/dev/mcd</tt>
<li>New Mitsumi, also not IDE <tt> /dev/mcdx0</tt>
<li>Sound Blaster Pro/Panasonic <tt>/dev/sbpcd</tt>
<li>Aztech/Orchid/Okano/Wearnes <tt>/dev/aztcd</tt>
<li>Phillips and some ProAudioSpectrum16 <tt>/dev/cm206cd</tt>
<li>Goldstar R420 <tt> /dev/gscd</tt>
<li>Optics Storage 8000 <tt> /dev/optcd</tt>
<li>Sanyo CDR-H94 + ISP16 soundcard <tt> /dev/sjcd</tt>
<li>Try to scan for your CD drive
</ol>
<I>1, 2, 3, 4, 5, 6, 7 8, 9, 10, 11, 12, or 13</I>
<B>IDE CD-ROM:</B> Enter the device name that represents
your IDE CD-ROM drive. This will probably be one of
these (in the order of most to least likely):
<tt>/dev/hdb /dev/hdc /dev/hdd /dev/hde /dev/hdf
/dev/hdg /dev/hdh /dev/hda</tt>
<I>Device name</I>
<li><B>SCSI CD-ROM:</B> Which SCSI CD-ROM are you using?
If you're not sure, select <tt>/dev/scd0</tt>.
<tt>1. /dev/scd0<br>
2. /dev/scd1</br></tt>
<li><B>Installation method:</B> With the Slackware CD, you can
run most of the system from the CD if you're short
of drive space or if you just want to test Linux
without going through a complete installation. Which
type of installation do you want (slakware or
slaktest)?
<ul>
<li>[slakware] Normal installation to hard drive
<li>[slaktest] Link <tt>family /usr-$>$/cdrom/live/usr</tt> to run mostly from CD-ROM
</ul>
<I>slakware or slaktext</I>
<li><B>Series Selection:</B> Identify which Packages you plan
to install. You may specify any combination of disk
sets at the prompt which follows. For example, to
install the base system, the base X Window System,
and the Tcl toolkit, you would enter: a x tcl Which
disk sets do you want to install?
<ul>
<li>[A] Base Linux system
<li>[AP] Various applications that do not need X
<li>[D] Program Development (C, C++, Kernel source, Lisp, Perl, etc.)
<li>[E] GNU Emacs
<li>[F] FAQ lists
<li>[K] Linux kernel source
<li>[N] Networking (TCP/IP, UUCP, Mail)
<li>[Q] Extra kernels with special drivers (needed for non-SCSI CD)
<li>[T] TeX
<li>[TCL] Tcl/Tk/TclX, Tcl language, and Tk toolkit for developing X apps
<li>[X] Xfree86 Base X Window System
<li>[XAP] X Window Applications
<li>[XD] Xfree86 X11 server development system
<li>[XV] Xview (OpenLook virtual Window Manager, apps)
<li>[Y] Games (that do not require X)
</ul>
<I>Any combination of a ap d e f k n q t tcl x xap xd xv y and other disk sets offered, separated by spaces</I>
<li><B>Software Installation:</B> Next, software packages are
going to be transferred on to your hard drive. If
this is your first time installing Linux, you should
probably use PROMPT mode. This will follow a
defaults file on the first disk of each series you
install that will ensure that required packages are
installed automatically. You will be prompted for
the installation of other packages. If you don't
use PROMPT mode, the install program will just go
ahead and install everything from the disk sets you
have selected. Do you want to use PROMPT mode
(y/n)?
<p>These defaults are user definable---you may set any
package to be added or skipped automatically by
editing your choices into a file called TAGFILE that
will be found on the first disk of each series.
There will also be a copy of the original tagfile
called TAGFILE.ORG available in case you want to
restore the default settings. The tagfile contains
all the instructions needed to completely automate
your installation.
<li>Would you like to use a special
tagfile extension?
<p>You can specify an extension
consisting of a "." followed by any combination of 3
characters other than <tt>tgz</tt>. For instance, I specify
'.pat', and then whenever any tagfiles called
'tagfile.pat' are found during the installation they
are used instead of the default "tagfile" files. If
the install program does not find tagfiles with the
custom extension, it will use the default tagfiles.
Enter your custom tagfile extension (including the
leading ("."), or just press <tt>Enter</tt> to continue
without a custom extension.
<I>Tagfile extension <tt>Enter</tt></I>
<li><B>Extra Configuration:</B> If you wish, you may now go
through the options to reconfigure your hardware,
make a bootdisk, and install LILO. If you've
installed a new kernel image, you should go through
these steps again. Otherwise, it's up to you.
<li><B>Boot Disk Creation:</B> It is recommended that you make
a boot disk. Would you like to do this? <I>Yes or No</I>.
<p>Now put a formatted floppy in your boot drive. This
will be made into your Linux boot disk. Use this to
boot Linux until LILO has been configured to boot
from the hard drive. Any data on the target disk
will be destroyed. Insert the disk and press
<tt>Return</tt>, or <tt>s</tt> if you want to skip this step.
<li><B>Modem Setup:</B> A link in <tt>/dev</tt> will be created from
your callout device (cua0, cua1, cua2, cua3) to
<tt>/dev/modem</tt>. You can change this link later if you
put your modem on a different port. Would you like
to set up your modem? <I>Yes or No</I>.
<li>These are the standard serial I/O devices,
Which
device is your modem attached to (0, 1, 2, 3)?
<ol>
<li><tt>/dev/ttyS0</tt> (or COM1: under DOS)
<li><tt>/dev/ttyS1</tt> (or COM2: under DOS)
<li><tt>/dev/ttyS2</tt> (or COM3: under DOS)
<li><tt>/dev/ttyS3</tt> (or COM4: under DOS)
</ol>
<li><B>Mouse Setup:</B> A link will be created in <tt>/dev</tt> from
your mouse device to <tt>/dev/mouse</tt>. You can change this
link later if you switch to a different type of
mouse. Would you like to set up your mouse? <I>Yes or No</I>.
<li>These types are supported. Which type of mouse do
you have (1, 2, 3, 4, 5, 6, 7)?
<ol>
<li>Microsoft compatible serial mouse
<li>QuickPort or PS/2 style mouse (Auxiliary port)
<li>Logitech Bus Mouse
<li>ATI XL Bus Mouse
<li>Microsoft Bus Mouse
<li>Mouse Systems serial mouse
<li>Logitech (MouseMan) serial mouse
</ol>
<I>1, 2, 3, 4, 5, 6, or 7</I>
<li>These are the standard serial I/O devices. Which
device is your mouse attached to (0, 1, 2, 3)?
<ol>
<li><tt>/dev/ttyS0</tt> (or COM1: under DOS)
<li><tt>/dev/ttyS1</tt> (or COM2: under DOS)
<li><tt>/dev/ttyS2</tt> (or COM3: under DOS)
<li><tt>/dev/ttyS3</tt> (or COM4: under DOS)
</ol>
<I>0, 1, 2, or 3</I>
<li><B>Network Configuration:</B> Now we will attempt to
configure your mail and TCP/IP. This process
probably won't work on all possible network
configurations, but should give you a good start.
You will be able to reconfigure your system at any
time by typing netconfig. First, we'll need the name
you'd like to give your host. Only the base hostname
is needed right now (not the domain). Enter the
hostname.
<I>Hostname</I>
<p>Now, we need the domain name. Do not supply a
leading "." Enter the domain name.
<I>Domain name</I>
<p>If you only plan to use TCP/IP through loopback,
then your IP address will be 127.0.0.1 and we can
skip a lot of the following questions. Do you plan
to ONLY use loopback? Yes or No.
<p>Enter your IP address for the local machine.
Example: 111.112.113.114. Enter the IP address for this
machine (aaa.bbb.ccc.ddd).
<I>IP address</I>
<li>Enter your gateway address, such as 111.112.113.1.
If you don't have a gateway, you can edit
/etc/rc.d/rc.inet1 later,or you can probably get
away with entering your own IP address here. Enter the
gateway address (aaa.bbb.ccc.ddd).
<I>IP address</I>
<li>Enter your netmask. This will generally look
something like this: 255.255.255.0. Enter the netmask
(aaa.bbb.ccc.ddd).
<I>IP address</I>
<li>Will you be accessing a nameserver? <I>Yes or No</I>.
<li>Please give the IP address of the name server to
use. You can add more Domain Name Servers by editing
<tt>/etc/resolv.conf</tt>. Name Server for your domain
(aaa.bbb.ccc.ddd)?
<I>HIP address</I>
</ul>
<p>You may now reboot your computer by pressing <tt>Ctrl+Alt+Delete</tt>.
If you installed LILO, remove the boot disk from your computer
before rebooting. Don't forget to create you <tt>{/etc/fsta</tt>
if you don't have one!
<h3>Making Slackware Happen</h3>
<p>If you've taken the time to plot and plan as recommended in the
preceding sections, then the actual installation will be a piece
of cake. There isn't much writing needed to explain the actual
process of loading Slackware onto your computer(s). You just follow
the steps to build boot and root diskettes, then answer a long
series of questions asked by the menu-driven Slackware installation
program. If you've completed the Slackware Installation Worksheet,
these questions will be familiar and everything will run smoothly.
<h3>Build Some Boot Disks</h3>
<p>Choose Your Kernel
<p>When installing Slackware Linux, you must create a boot diskette
with a Linux kernel that is specially prepared to recognize your
system hardware. For example, to install Slackware from an IDE
CD-ROM drive onto a SCSI hard drive, the kernel that you put onto
the boot diskette will need to have drivers for your SCSI card
and your IDE CD-ROM drive.
<p>The kernels are stored as compressed <I>binary image</I> files
that you can access from most any operating system to create a
Slackware Boot diskette. On the Slackware FTP site, CD-ROM, or
NFS mount, you'll find a subdirectory called bootdsks.144-containing
1.44 MB kernel images for creating boot disks on 1.44MB high density
3.5'' floppy diskettes. If you're working from a 5.25'' floppy
diskette drive, look in a directory called bootdsks.12 for
kernel images that will fit the smaller diskette format.
<p>Table 2 provides a quick reference of the kernel images available
as we went to press. Information and up-to-date boot disk image
information is available from this URL:
<a href="ftp://ftp.cdrom.com/pub/linux/slackware/bootdsks.144/README.TXT">ftp://ftp.cdrom.com/pub/linux/slackware/bootdsks.144/README.TXT</a><br>
<center><h3>Slackware Boot Kernel Image Descriptions</h3></center>
<P><B>Table 1</b>
<p>
<table cellpadding 10>
<tr>
<td valighn=top>aztech.i</td> <td>CD-ROM drives: Aztech CDA268-01A,
Orchid CD-3110, Okano/Wearnes,
CDD110, Conrad TXC, CyCDROM CR520,
CR540<br></td>
</tr>
<tr>
<td valign=top>bare.i</td> <td>(none, just IDE support)<br></td>
</tr>
<tr>
<td valign=top>cdu31a.i</td> <td>Sony CDU31/33a CD-ROM<br></td>
</tr>
<tr>
<td>cdu535.i</td> <td>Sony CDU531/535 CD-ROM<br></td>
</tr>
<tr>
<td>cm206.i</td> <td>Philips/LMS cm206 CD-ROM with cm260
adapter card<br></td>
</tr>
<tr>
<td>goldstar.i</td> <td>Goldstar R420 CD-ROM (sometimes sold
in a Reveal "Multimedia Kit")<br></td>
</tr>
<tr>
<td>mcd.i</td> <td>NON-IDE Mitsumi CD-ROM support<br></td>
</tr>
<tr>
<td>mcdx.i</td> <td>Improved NON-IDE Mitsumi CD-ROM
support<br></td>
</tr>
<tr>
<td>net.i</td> <td>Ethernet support<br></td>
</tr>
<tr>
<td>optics.i</td> <td>Optics Storage 8000 AT CD-ROM (the
"DOLPHIN" drive)<br></td>
</tr>
<tr>
<td>sanyo.i</td> <td>Sanyo CDR-H94A CD-ROM support<br></td>
</tr>
<tr>
<td>sbpcd.i</td> <td>Matsushita, Kotobuki, Panasonic,
CreativeLabs (Sound Blaster),
Longshine and Teac NON-IDE CD-ROM
support<br></td>
</tr>
<tr>
<td>xt.i</td> <td>MFM hard drive support<br></td>
</tr>
</table>
<p><b>Table 2</b>
<p>
<table cellpadding 10>
<tr>
<td>7000fast.s</td> <td>Western Digital 7000FASST SCSI support<br></td>
</tr>
<tr>
<td>Advansys.s</td> <td>AdvanSys SCSI support<br></td>
</tr>
<tr>
<td>Aha152x.s</td> <td>Adaptec 152x SCSI support<br></td>
</tr>
<tr>
<td.Aha1542.s</td> <td>Adaptec 1542 SCSI support<br></td>
</tr>
<tr>
<td>Aha1740.s</td> <td>Adaptec 1740 SCSI support<br></td>
</tr>
<tr>
<td>Aha2x4x.s</td> <td>Adaptec AIC7xxx SCSI support (For these cards: AHA-274x, AHA-2842,
& AHA-2940, AHA-2940W, AHA-2940U, AHA-2940UW, AHA-2944D, AHA-2944WD,
& AHA-3940, AHA-3940W, AHA-3985, AHA-3985W)<br></td>
</tr>
<tr>
<td>Am53c974.s</td> <td>AMD AM53/79C974 SCSI support<br></td>
</tr>
<tr>
<td>Aztech.s</td> <td>All supported SCSI controllers, plus CD-ROM support for Aztech CDA268-01A,
Orchid CD-3110, Okano/Wearnes CDD110, Conrad TXC, CyCDROM CR520, CR540<br></td>
</tr>
<tr>
<td>Buslogic.s</td> <td>Buslogic MultiMaster SCSI support<br></td>
</tr>
<tr>
<td>Cdu31a.s</td> <td>All supported SCSI controllers, plus CD-ROM support for Sony CDU31/33a<br></td>
</tr>
<tr>
<td>Cdu535.s</td> <td>All supported SCSI controllers, plus CD-ROM support for Sony CDU531/535<br></td>
</tr>
<tr>
<td>Cm206.s</td> <td>All supported SCSI controllers, plus Philips/LMS cm206 CD-ROM with cm260 adapter card<br></td>
</tr>
<tr>
<td>Dtc3280.s</td> <td>DTC (Data Technology Corp) 3180/3280 SCSI support<br></td>
</tr>
<tr>
<td>Eata\_dma.s</td> <td>DPT EATA-DMA SCSI support (Boards such as PM2011, PM2021, PM2041,
& PM3021, PM2012B, PM2022, PM2122, PM2322, PM2042, PM3122, PM3222,
& PM3332, PM2024, PM2124, PM2044, PM2144, PM3224, PM3334.)<br></td>
</tr>
<tr>
<td>Eata\_isa.s</td> <td>DPT EATA-ISA/EISA SCSI support (Boards such as PM2011B/9X,
& PM2021A/9X, PM2012A, PM2012B, PM2022A/9X, PM2122A/9X, PM2322A/9X)<br></td>
</tr>
<tr>
<td>Eata\_pio.s</td> <td>DPT EATA-PIO SCSI support (PM2001 and PM2012A)<br></td>
</tr>
<tr>
<td>Fdomain.s</td> <td>Future Domain TMC-16x0 SCSI support<br></td>
</tr>
<tr>
<td>Goldstar.s</td> <td>All supported SCSI controllers, plus Goldstar R420 CD-ROM (sometimes sold
in a Reveal "Multimedia Kit")<br></td>
</tr>
<tr>
<td>In2000.s</td> <td>Always IN2000 SCSI support<br></td>
</tr>
</table>
<p><b>Table 3</b>
<table cellpadding 10>
<tr>
<td>Iomega.s</td> <td>IOMEGA PPA3 parallel port SCSI support (also supports the parallel
port version of the ZIP drive)<br></td>
</tr>
<tr>
<td>Mcd.s</td> <td>All supported SCSI controllers, plusstandard non-IDE Mitsumi CD-ROM support<br></td>
</tr>
<tr>
<td>Mcdx.s</td> <td>All supported SCSI controllers, plus enhanced non-IDE Mitsumi CD-ROM support<br></td>
</tr>
<tr>
<td>N53c406a.s</td> <td>NCR 53c406a SCSI support<br></td>
</tr>
<tr>
<td>N\_5380.s</td> <td>NCR 5380 and 53c400 SCSI support<br></td>
</tr>
<tr>
<td>N\_53c7xx.s</td> <td>NCR 53c7xx, 53c8xx SCSI support (Most NCR PCI SCSI controllers use this driver)<br></td>
</tr>
<tr>
<td>Optics.s</td> <td>All supported SCSI controllers, plus support for the Optics Storage 8000
AT CDROM (the "DOLPHIN" drive)<br></td>
</tr>
<tr>
<td>Pas16.s</td> <td>Pro Audio Spectrum/Studio 16 SCSI support<br></td>
</tr>
<tr>
<td>Qlog\_fas.s</td> <td>ISA/VLB/PCMCIA Qlogic FastSCSI! support (also supports the Control
Concepts SCSI cards based on the Qlogic FASXXX chip)<br></td>
</tr>
<tr>
<td>Qlog\_isp.s</td> <td>Supports all Qlogic PCI SCSI controllers, except the PCI-basic,
which the AMD SCSI driver supports <br><td>
</tr>
<tr>
<td>Sanyo.s</td> <td>All supported SCSI controllers, plus Sanyo CDR-H94A CD-ROM support<br></td>
</tr>
<tr>
<td>Sbpcd.s</td> <td>All supported SCSI controllers, plus Matsushita, Kotobuki, Panasonic,
CreativeLabs (Sound Blaster), Longshine and Teac NON-IDE CDROM support<br></td>
</tr>
<tr>
<td>Scsinet.s</td> <td>All supported SCSI controllers, plus full ethernet support<br></td>
</tr>
<tr>
<td>Seagate.s</td> <td>Seagate ST01/ST02, Future Domain TMC-885/950 SCSI support<br></td>
</tr>
<tr>
<td>Trantor.s</td> <td>Trantor T128/T128F/T228 SCSI support<br></td>
</tr>
<tr>
<td>Ultrastr.s</td> <td>UltraStor 14F, 24F, and 34F SCSI support<br></td>
</tr>
<tr>
<td>Ustor14f.s</td> <td>UltraStor 14F and 34F SCSI support<br></td>
</tr>
</table>
<p><b>Unix Operating Systems</b>
<p>If you have the Slackware kernel images on a Unix host that has
a floppy drive, you can quickly create the necessary boot and
root diskettes using Unix commands. You can use the dd
command. The example below which puts the scsi.s
boot kernel image onto the floppy device rfd0:
<tt>dd if=scsi.s of=/dev/rfd0 obs=18k</tt>
<p>You'll need to repeat this process with one of the root disk images
onto a second floppy diskette.
<p>DOS, OS/2, MS-Windows 95 \& NT
<p>Slackware bundles a utility called rawrite.exe that
will generate boot and root diskettes under DOS-literate operating
systems. To write the scsi.s kernel image onto the
formatted, high-density diskette in your A:$\backslash$ diskette
drive, issue the following command:
<tt>RAWRITE SCSI.S A:</tt>
<p>You'll need to repeat this process with one of the root disk images
onto a second floppy diskette.
<h3>Boot Into Action</h3>
<p>Here's the big anticlimax. After all this planning, preparation,
and partitioning, you're in the home stretch. Make sure the boot
floppy is in the diskette drive, and restart your computer. Now
is a good time to go get some coffee (or whatever you like to
keep you company) and return to the machine ready to play the
part of a button-pushing drone, answering yes-no questions for
an hour or so.
<p>Log in as root (no password) and type setup
or setup.tty
<a name="slack2"></a>
<h3>Slackware Setup Program</h3>
<p>Slackware comes with two versions of an excellent setup program.
One is a colorful, dialog-based, menu-driven version. An alternative
setup, setup.tty, is a text-only version of the installation
that you may actually prefer, because detailed diagnostics and
error messages will stay on the screen and not be erased by the
next dialog box, which happens in the color version. If you're
attempting a Slackware setup on sketchy hardware, I strongly recommend
the less colorful setup.tty routine. If you don't
know much about Unix and would feel more comfortable with an attractive.
``clean'' interface to the same setup process, then by all means
go for the beautiful setup.
<h3><center>Slackware96 Linux Setup (version HD-3.1.0)</center></center></h3>
<h3>Welcome to Slackware Linux Setup</h3>
<p>Hint: If you have trouble using the arrow keys on your keyboard,
you can use '+', '-', and TAB instead. Which option would you like?
<ul>
<li> HELP: Read the Slackware Setup HELP file
<li> KEYMAP: Remap your keyboard
<li> MAKE TAGS: Tagfile customization program
<li> TARGET: Select target directory [now: / ]
<li> SOURCE: Select source media
<li> DISK SETS: Decide which disk sets you wish to install
<li> INSTALL: Install selected disk sets
<li> CONFIGURE: Reconfigure your Linux system
<li> PKGTOOL: Install or remove packages with Pkgtool
<li> EXIT: Exit Slackware Linux Setup
OK Cancel
</ul>
<p>To transfer Slackware onto your system from here should involve
little more than selecting what you want off the menus. By filling
out the Section 3 worksheet in advance, you should be able progress
quickly through each menu in order, until you reach the INSTALL
option, at which point things may s l o w down: you are advised
to select the PROMPT feature and <I>read</I> about each software
package, deciding whether or not you'd like it to end up on your
Slackware system. The last part of a regular setup is the CONFIGURE
section on the setup menu, and the questions you must answer bear
a striking resemblance to the second half of the Section 3 worksheet.
<h3>Is That All?</h3>
<p>Definitely not! At this point, you've either got some annoying
obstacle that is preventing the setup from completing, or more
likely, you're looking at the root prompt
<tt>darkstar\~\#</tt><br>
and wondering "What Next?"
<p>Well, if you're plagued by problems, you'll want to proceed directly
to the next section on troubleshooting. If things appear to be
in working order, you've still got some details to attend to.
Sort of like purchasing a new automobile-after you've selected
an paid for a new car, there are still some things you need before
you can drive it with confidence-insurance, a steering wheel club,
and perhaps some luxuries that make the driving experience closer
to Fahrvergn\&uuml;gen than FAQ!
<a name="trouble"></a>
<h3>Troubleshooting Difficult Deliveries</h3>
<p>Not every Slackware installation is born on cue to expecting system
administrators. I've pulled a few all nighters, sitting down after
work one evening to upgrade a Slackware box and still there struggling
to get the damn thing back online at dawn, before people start
bitching about their missing mail and news. This section will
look at a few common Slackware setup problems, solutions, and
where to look for additional assistance.
<h3>Slackware Installation FAQs</h3>
<p>Patrick Volkerding, the father of Slackware, has dealt with the
many questions of new users by listening, answering, and anticipating
repeat queries. To catch the new Slackware users before they ask
the same question for the 5,000th time, Patrick has kindly created
documentation and included it with the Slackware distribution.
Three files that you may find very helpful in answering your initial
questions are FAQ.TXT, INSTALL.TXT, and BOOTING.TXT.
<p>Web Support For Slackware
<p>At this time, the Slackware-specific help you'll find on the Internet
tends to be highly customized---such as how to NFS-mount the distribution
on computers within a certain university or how to wire your dorm
room into a particular residential WAN using Slackware.
<p>Usenet Groups For Slackware
<p>The comp.os.linux.* hierarchy of the Usenet is a
treasure-trove of Linux information, not necessarily Slackware-specific.
At present, 11 separate Linux forums handle a high volume of discussion
in this hierarchy. Dozens of other general-Unix newsgroups are
also available. Some discussions relevant to getting Slackware
up and running are:
<ul>
<li>comp.os.linux.setup
<p>A group established for figuring out Linux installation and system
administration. The best place to look for clever setup strategies
and to network with others who may have recently installed Slackware.
<li>comp.os.linux.announce
<p>A must-read for Linux administrators and enthusiasts, C.o.l.a
is a sort of daily Linux digest for the Internet community. The
group is moderated, so only the relevant material makes it into
circulation. The newsgroup is designed as a low-traffic alert
service for announcing Linux-specific software, documentation,
and security warnings.
<li>comp.os.linux.answers
<p>Here's where to find (or post) the latest Linux FAQs, How-Tos,
READMEs and other documents that answer questions about Linux.
</ul>
<p>Mail Lists For Slackware
<p>At this time, there are no electronic mail discussions devoted
to Slackware per-se. You can participate in some excellent Linux-related
talk via e-mail, try www.linux.org and asking in the newsgroups
for a few good subscription lists.
<h3>You Get What You Pay For (Commercial Support)</h3>
<p>Commercial support for Linux is available from some of the CD-ROM
vendors and a long list of Linux Consultants, who can be contacted
through the Linux Commercial and Consultants HOWTO documents:
<a href="http://sunsite.unc.edu/LDP/HOWTO/Consultants-HOWTO.html">http://sunsite.unc.edu/LDP/HOWTO/Consultatns-HOWTO.html</a><br>
<a href="http://sunsite.unc.edu/LDP/HOWTO/Commercial-HOWTO.html">http://sunsite.unc.edu/LDP/HOWTO/Commercial-HOWTO.html</a><br>
<a name="basking"></a>
<h3>Basking In the Afterglow</h3>
<p>Don't rest on your laurels quite yet. Especially if your Slackware
machine is a shared computer or lives in a networked environment.
Grooming a computer for community and network use is a bit more
demanding than just running the setup program and
forgetting about it. We'll leave you with a few pointers to securing
and sharing your new Slackware system.
<h3>Consider Reinstalling!</h3>
<p>I know you just sat through what may have been a long and perplexing
installation session. But before you move into the house you just
built, consider tearing it down and starting over again. Friedrich
Nietzsche had a quote:
"A man learns what he needs to know about building his house only
after he's finished."
<p>If, in the process of installing the system, you had some thoughts
about how you might do it differently, now is the time. If your
Slackware Linux box will be a multi user machine or a network
server, there may never be such a convenient opportunity to reinstall
or reconfigure the system in radical ways.
<a name="install"></a>
<h3>Install And Test Key Applications</h3>
<p>Before you put away the CDROM or return the 50 floppy disks you
borrowed to run the Slackware installation, sit down and test
each application that your users may expect to find in working
order. If professor Bien absolutely has to have emacs humming
under X-Windows, you'd better test it out now, while you've still
got the workstation 'in the shop.'
<p>Did you set up this Linux box to serve a specific purpose in your
organization, such as...
<ul>
<li><b>File and Print Server for Macintoshes or Windows PCs:</b>
Better make sure netatalk, CAP and samba are configured and tested
<li><b>World Wide Web Server:</b>
Time to choose a www daemon and get it up and running
<li><b>Mail Server:</b>
Have you configured sendmail? How alternative
mail applications that offer improved performance, features, or
security over their Slackware-default counterparts? Most mail
servers would benefit from cucipop, procmail,
and Smarlist, to name a few.
<li><b>Remote Access Server:</b>
Got those serial ports or add-in boards working?
<li><b>Firewall:</b>
You might like to look at the second firewall toolkit from
TIS, as well as front-ends to ease firewall and network administration,
such as linuxconf.
</ul>
<a name="secure"></a>
<h3>Secure the System</h3>
<p><b>Get Off The LAN At Once</b>
<p>Out of the box, Slackware is an insecure system. Although Patrick
does his best to create a secure distribution, a few inevitable
holes become known, and patches or workarounds are made available
in the system administration (and cracker) communities. If you
installed Slackware from a network source such as an NFS-mounted
drive, you should temporarily disconnect your box from the LAN
after a successful installation, while you plug a few holes.
<p><b>Give Root a Password</b>
<p>By default, a new Slackware box will not require a password for
the root user. When you're comfortable that your
new Slackware system is stable (after a few hours, not days or
weeks), add a password to protect the root account.
Login as root and type:
<tt>passwd root</tt>
<p><b>Give Yourself An Account</b>
<p>On large shared systems, the super-user root account is not used as a
working login account by any individual. If you're interested in
system administration or are running a networked machine, this is a
good precedent to follow. Use the \texttt{/sbin/adduser} program to
make yourself a login account, rather than working out of the root
login. I always smile when I see students and hobbyists posting
proudly to the Usenet as root@mymachine.mydomain. Be humble and safe,
create another login account for your daily work and use su (rather
than login) to enter the root account sparingly.
<p><b>Deny Root Logins</b>
<p>Not only is it uncommon to <I>work</I> as the root user,
it is <I>not considered secure to login as root across the network</I>.
Administrative users usually connect to a Unix box as their regular
username login, and then use the su utility to become
the root user as needed. To prevent crackers, hackers, and ignorant
users from logging in directly as root, edit the file <tt>/etc/securetty</tt>
and comment out (prepend a pound \# sign before) all but the local
terminals:
<tt>console
tty1
tty2
\# ttyS0
\# ttyS1
</tt>
<p>After this fix, users who attempt to login in as root across
the network will be denied:
<tt>Linux 2.0.29 (durak.interactivate.com)<br>
durak login: root<br>
root login refused on this terminal.<br>
durak login:</tt>
<p><b>Apply the Simple Fixes</b>
<p>Slackware installs itself with some very real security problems.
Rather than master Unix security and sleuth out these vulnerabilities
yourself, you can jump start the hole-patching process by visiting
a web resource maintained for just this purpose, called <I>Slackware
SimpleFixes</I>:
<a href="http://cesdis.gsfc.nasa.gov/linux-web/simplefixes/simplefixes.html">http://cesdis.gsfc.nasa.gov/linux-web/simplefixes/simplefixes.html</a><br>
<p><b>Check For Patches On ftp.cdrom.com</b>
<p>As an actively maintained Linux distribution Slackware updates
and patches are available from:
<a href="ftp://ftp.cdrom.com/pub/linux/slackware/patches/">ftp://ftp.cdrom.com/pub/linux/slackware/patches/</a><br>
<p><b>Stay Current</b>
<p>You might like to subscribe to one or more electronic mail lists
that alert users to issues in Linux administration, such as:
<ul>
<li>linux-alert-request@tarsier.cv.nrao.edu
<li>linux-security-request@redhat.com
</ul>
<a name="backup"></a>
<h3>Back Up</h3>
<p>Like how things are running? Save it for a rainy day by backing
up. Amanda (The Advanced Maryland Automatic Network Disk Archiver)
is one of several backup options for Linux installations. You
can learn more about Amanda from:
<a href="http://www.cs.umd.edu/projects/amanda/index.html">http://www.cs.umd.edu/projects/amanda/index.html/</a><br>
<!--===================================================================-->
<P> <hr> <P>
<center><H5>Copyright &copy; 1997, Sean Dreilinger<BR>
Published in Issue 17 of the Linux Gazette, May 1997</H5></center>
<!--===================================================================-->
<P> <hr> <P>
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<H4>
&quot;Linux Gazette...<I>making Linux just a little more fun!</I>&quot;
</H4>
<P> <HR> <P>
<!--===================================================================-->
<center>
<H2>Linux Installation Project</H2>
<H4>By Kendall G. Clark,
<a href="mailto:kclark@dal284.computek.net">kclark@dal284.computek.net</a></H4>
</center>
<P> <HR> <P>
<h1>Linux Installation Project</h1>
<p>
It all started with a simple question: `Why don't we install
Linux at all our meetings instead of at only some of them?'
The <a href="http://www.ntlug.org/">North Texas Linux Users
Group</a> had been in existence for only about five months,
and we wanted to make sure to spread the word in North Texas
about Linux. We wanted to educate the computing public in our
area about Linux, but we also wanted to let experienced
computer users know that Linux could handle anything they
threw at it.
<p>
After meeting at Texas Christian University for our first few
meetings, we signed a contract with the <a
href="http://www.dfwxchange.com/dfwx.nsf/?Open">DFWXchange</a> that enabled NTLUG
to meet at the <a href="http://www.infomartusa.com">Dallas
Infomart</a>. The DFWXchange is an umbrella organization that
allows Dallas-Fort Worth users groups to meet at the Infomart
for free, with all costs being absorbed by the many commercial
vendors who also meet at the Infomart during the Super Satuday
Sale. So every month between 3,000 and 5,000 computer users
from the Dallas-Fort Worth Metroplex converge on the
Infomart---the premier meeting facility in the Southwest
devoted exclusively to computer and technology events and
organziations---to participate in users groups meetings and to
take advantage of some really good prices on computer-related
hardware. It's a big party.
<p>
It didn't take long for the NTLUG leadership to realize that
we had stumbled upon a great opportunity: we wanted to let
computer users in our area know about Linux, and we were now
meeting every month in a facility filled with thousands of
potential Linux converts. Our solution was to start the
<b>Linux Installation Project</b>, which we call the
<b>LIP</b>.
<p>
The goal of <b>LIP</b> is simply to install Linux on as many
computers as possible. Those of us who participate in this
project month-to-month have discovered that the very best way
to advocate the use of Linux is to make it easy and painless
for the unconverted to do just that: namely, run Linux on
their computer of choice. In other words, Linux is its own
best advocate. After a few weeks without a crash, most people
say goodbye to Windows 95 with zealous enthusiasm. We like to
think of <b>LIP</b> as an ongoing Linux Installation Festival
that allows us to convert computer users to Linux one at a
time.
<p>
The first step in establishing <b>LIP</b> as a well-run,
consistent endeavor was to find someone to lead the
effort. NTLUG is fortunate to have a technologically advanced
membership, and it was fairly easy to find someone to lead the
<b>LIP</b>; in fact, we found two such people: Mike Dunn and
Bill Petersen, both of whom are experienced Unix and Linux
Sysadmins. Under their guidance, and due to the generosity of
NTLUG members, NTLUG's <b>LIP</b> has solicited and organized
enough computer hardware to perform up to many simultaneous
installations of Linux by all the usual methods, although
we've found that cdrom installations are usually the most
trouble free.
<p>
The word has now spread in and around the Dallas-Fort Worth
Metroplex---from schools and universities to computer vendors
and other users groups---that NTLUG's <b>LIP</b> is the place
to go for a painless installation of Linux onto PCs, laptops,
servers, and even Alpha platforms. We have expanded our
efforts at the <b>LIP</b> booth to include Linux advocacy,
advertisement for Linux vendors who supply us with materials,
the sale of Linux CDs (thanks to Bradley Glonka at <a
href="http://www.lsl.com/">Linux Systems Labs</a>), and even
basic Linux system administration and maintenance. We also
spend a lot of time explaining to the uninitiated masses what
makes Linux <b><i>free</i></b> and what makes it so much fun.
<p>
While we have been happy with the results so far, the
<b>LIP</b> has more work to do. We want to expand our sales
efforts to include other kinds of Linux merchandise (the sales
of which go to support NTLUG and <b>LIP</b>), and we'd also
like to expand our hardware assets to enable more simultaneous
installations. Finally, we also want to develop our users
group assets to such an extent that we can go to other
DFW-area computer events and setup Linux installation and
advocacy booths. NTLUG's approach to the Linux Installation
Project can be summed up in the phrase: "Linux is free. Life
is good."
<p>
If you want to learn more about the North Texas Linux Users
Group or our Linux Installation Project, or if you're a Linux
Users Group and would like to talk about setting up your own
local version of <b>LIP</b>, please visit the <a
href="http://www.ntlug.org/">NTLUG</a> website or contact me
at <i><a
href="mailto:kclark@computek.net">kclark@computek.net</a></i>.
<p>
Finally, I would be guilty of ingratitude if I did not thank
the following people and organizations that have made the
<b>LIP</b> possible. Please forgive me if I've forgotten
anyone. It's just about impossible not to meet great people
when you work with Linux.
<ul>
<ul>
<b>NTLUG Members</b>
<li>Mike Dunn</li>
<li>Bill Petersen</li>
<li>Thomas Griffing</li>
<li>Bill Richards</li>
<li>Steve Brennan</li>
<li>Allen Prince</li>
<li>Pete Koren</li>
<li>Eric Chang</li>
<li>everyone else who made financial and hardware donations</li>
</ul>
<ul>
<b>Organizations</b>
<li><a href="http://www.lsl.com/">Linux Systems Labs</a>, especially Bradley Glonka</li>
<li><a href="http://www.redhat.com/">Red Hat Software</a></li>
<li><a href="http://www.swt.com/">SouthWest Technology</a></li>
<li><a href="http://www.dfwxchange.com/">DFWXchange</a>, especially Stuart Yarus, President.</li>
</ul>
</ul>
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<P> <hr> <P>
<center><H5>Copyright &copy; 1997, Kendall G. Clark <BR>
Published in Issue 17 of the Linux Gazette, May 1997</H5></center>
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<H5>Copyright &copy; 1997 Specialized Systems Consultants, Inc.<br>
For information regarding copying and distribution of this material see the
<A HREF="../copying.html">Copying License</A>.</H5>
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<P> <hr> <P>
<H3>Contents:</H3>
<ul>
<li><a HREF="./lg_backpage17.html#authors">About This Month's Authors</a>
<li><a HREF="./lg_backpage17.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">Larry Ayers</H4>
Larry Ayers 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">Kendall G. Clark</H4>
Kendall Clark is a PHD candidate in systematic theology at
Southern Methodist University. He
is hard at work on his dissertation using Red Hat 4.1, LaTeX,
and AucTeX & Xemacs. He helped found <a
href="http://www.ntlug.org/">NTLUG</a> in the summer of 1996
with Stephen Denny and Tim Jones and currently serves as Acting
President. He makes his home with his wife Hope in Dallas,
Texas.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Jim Dennis</H4>
Jim Dennis
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">Sean Dreilinger</H4>
Sean Dreilinger
suffered through two years of Los Angeles smog for a Masters degree in
library/information systems at UCLA. Linux swept him off his feet in grad
school and turned into a Network Administration career for the University.
Consulting on Internet strategy and info-system design in assorted
bored-rooms followed. Today he beams-in to www.interactivate.com from a
remote mountain cabin near Cuyamaca, California and is only required to
show his face at work once a week--nice job for the outdoors-loving and
socially inept. He lives with his lover Kathy and this incredible
high-altitude silence--punctuated only by the sound of wind rustling in the
Manzanita trees, hummingbirds fighting for a perch on the feeder, and that
reassuring whir of SCSI drives dancing with Linux under the desk. More life
story with explicit photos can be found at http://www.interactivate.com/people/sean/.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Jon "maddog" Hall</H4>
Jon "maddog" Hall is Senior Leader of Digital UNIX
Base Product Marketing, Digital Equipment Corporation.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Michael J. Hammel</H4>
Michael J. Hammel,
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">Rick Hohensee</H4>
Rick Hohensee is a guitar bum and former construction executive who has
so many irons in the fire he can't keep the fire going. Visit him on
the web at http://cqi.com/~humbubba.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Mike List </H4>
Mike List is a father of four teenagers, musician, printer (not
laserjet), and recently reformed technophobe, who has been into computers
since April,1996, and Linux since July.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Jesper Pedersen</a></H4>
Jesper Pedersen lives in Odense, Denmark, where he has studied computer science
at Odense University since 1990. He expects to obtain his degree in a year and
a half. He has a great job as a system manager at the
university, and also teaches computer science two hours a week. He is very
proud of his &quot;child,&quot; The Dotfile Generator, which he wrote as part of his
job at the university. The idea for it came a year and a half ago, when he had
to learn how to configure Emacs by reading about 700 pages of the lisp manual.
It started small, but as time went by, it expanded into a huge project.
In his spare time, he does Yiu-Yitsu, listens to music, drinks beer and has fun with
his girl friend. He loves pets, and has a 200 litre aquarium and two very cute
rabbits.
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Jay Painter</a></H4>
Jay Painter is the Systems Administrator at SSC.
<a name="notlinux"></a>
<P> <hr> <P>
<!--====================================================================-->
<center><H3> Not Linux </H3></center>
<P> <HR> <P>
<!--======================================================================-->
<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. And many, many thanks to Amy for doing most of the work
this month.
<P>
<IMG ALIGN="LEFT" ALT="" SRC="../gx/rose.gif">
Seattle--always a wonderful event. Riley and I spent the morning working
in the yard, clearing out a flower bed that was overgrown with grass. It
felt like hard physical labor after sitting at a desk all week. We rewarded
ourselves by taking a spin on the motorcycle along the Sound. Even as
passenger there is something about riding on a motorcycle that puts a smile
on my face. I guess it helps that I have complete trust in Riley's driving
abilities.
<P>
Afterward I went to the Opera House for a talk about <I>Il Trovatore</I> by
Giuseppe Verdi (or Joe Green, as Riley likes to call him). I had seen
the opera itself on Wednesday night--a silly
story as usual but, oh, such
wonderful music! I think it has to be one of my favorites. At any rate
the talk was informative and fun and made a nice end to a very wonderful
day.
<P>
Have fun!
<P> <hr> <P>
<A HREF="http://www.ssc.com/ssc/Employees/Margie/margie.html">
Marjorie L. Richardson</a><br>
Editor, <i>Linux Gazette</i> <A HREF="mailto:gazette@ssc.com">gazette@ssc.com</a>
<P> <HR> <P>
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<p><hr><p>
<I>Linux Gazette</I> Issue 17, May 1997, http://www.ssc.com/lg/<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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