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<HTML><HEAD><TITLE> Linux Gazette Table of Contents LG #85</TITLE></HEAD>
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<H2>December 2002, Issue 85 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Published by <I>Linux Journal</I></H2>
<A HREF="../index.html">Front Page</A> &nbsp;|&nbsp;
<A HREF="../index.html">Back Issues</A> &nbsp;|&nbsp;
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<!-- H1><font color="#BB0000">Table of Contents:</font></H1 -->
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<UL>
<LI> <A HREF="lg_mail.html">The MailBag</A>
<LI> <A HREF="lg_tips.html">More 2-Cent Tips</A>
<LI> <A HREF="lg_answer.html">The Answer Gang</A>
<LI> <A HREF="lg_bytes.html">News Bytes</A>, <EM>by Michael Conry</EM>
<LI> <A HREF="collinge.html">HelpDex</A>, <EM>by Shane Collinge</EM>
<LI> <A HREF="ecol.html">Ecol</A>, <EM>by Javier Malonda</EM>
<LI> <A HREF="johnson.html">Modern Linux Distributions and Hardware-Challenged PCs</A>, <EM>by Richard Johnson</EM>
<LI> <A HREF="lodato.html">Handicapped People of the World, Unite!</A>, <EM>by Janine M Lodato</EM>
<LI> <A HREF="mahoney.html">So You Wanna Create Your Own x86 Operating System?</A>, <EM>by Patrick Mahoney</EM>
<LI> <A HREF="nielsen.html">Viewing Faxes on the Web</A>, <EM>by Mark Nielsen</EM>
<LI> <A HREF="okopnik.html">Perl One-Liner of the Month: The Case of the Duplicate UIDs</A>, <EM>by Ben Okopnik</EM>
<LI> <A HREF="foolish.html">The Foolish Things We Do With Out Computers</A>, <EM>by Mike ("Iron") Orr</EM>
<LI> <A HREF="ortiz.html">Programming Bits: C# Data Types</A>, <EM>by Ariel Ortiz Ramirez</EM>
<LI> <A HREF="qubism.html">Qubism</A>, <EM>by Jon "Sir Flakey" Harsem</EM>
<LI> <A HREF="sandeep.html">Process Tracing Using Ptrace - Part III</A>, <EM>by Sandeep S</EM>
<LI> <A HREF="sipos.html">Making a Multiple-Boot CD</A>, <EM>by Juraj Sipos</EM>
<LI> <A HREF="vinayak.html">Getting started with TUX</A>, <EM>by Vinayak Hegde</EM>
<LI> <A HREF="lg_backpage.html">The Back Page</A>
</UL>
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<H3 ALIGN="center"><EM>Linux Gazette</EM> Staff and The Answer Gang</H3>
<BLOCKQUOTE>
<STRONG>Editor:</STRONG> Michael Orr<BR>
<STRONG>Technical Editor:</STRONG> Heather Stern<BR>
<STRONG>Senior Contributing Editor:</STRONG> Jim Dennis<BR>
<STRONG>Contributing Editors:</STRONG>
Ben Okopnik, Dan Wilder, Don Marti
</BLOCKQUOTE>
<HR NOSHADE>
<!--=================================================================-->
<A HREF="TWDT.txt.gz">TWDT 1 (gzipped text file)</A><BR>
<A HREF="TWDT.html">TWDT 2 (HTML file)</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.
<HR NOSHADE>
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<I>Linux Gazette</I><img alt="[tm]" src="../gx/tm.gif">,
<A HREF="http://www.linuxgazette.com/">http://www.linuxgazette.com/</A><BR>
This page maintained by the Editor of <I>Linux Gazette</I>,
<A HREF="mailto: gazette@ssc.com"> gazette@ssc.com</A>
<P>
<H5>Copyright &copy; 1996-2002 Specialized Systems Consultants, Inc.</H5>
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<TABLE BORDER><TR><TD WIDTH="200">
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<IMG ALT="LINUX GAZETTE" SRC="/gx/2002/lglogo_200x41.png"
WIDTH="200" HEIGHT="41" border="0"></A>
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD>
<center>
<BIG><BIG><STRONG><FONT COLOR="maroon">The Mailbag</FONT></STRONG></BIG></BIG><BR>
<!-- BEGIN wanted -->
<STRONG>From <A HREF="mailto:gazette@ssc.com">The Readers of <i>Linux Gazette</I></A></STRONG></BIG>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<HR>
<center>
<BIG><STRONG><FONT COLOR="maroon">HELP WANTED : Article Ideas</FONT></STRONG></BIG>
<BR>
<STRONG>Submit comments about articles, or articles themselves (after reading <a href="../faq/author.html">our guidelines</a>) to <A HREF="mailto:gazette@ssc.com">The Editors of <i>Linux Gazette</I></A>, and technical answers and tips about Linux to <A HREF="mailto:linux-questions-only@ssc.com">The Answer Gang</A>.
</STRONG>
</center><HR>
<UL>
<!-- index_text begins -->
<li><A HREF="#wanted/1"
><strong>What do I do to make evolution sync with a Visor PDA?</strong></a>
<li><A HREF="#wanted/2"
><strong>Redhat 7.1 freezes often</strong></a>
<li><A HREF="#wanted/3"
><strong>How can i determine IP address of client?</strong></a>
<li><A HREF="#wanted/4"
><strong>Question</strong></a>
<li><A HREF="#wanted/5"
><strong>glibc versioning</strong></a>
<li><A HREF="#wanted/6"
><strong>Alan Turing</strong></a>
<!-- index_text ends -->
</UL>
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<P> <A NAME="wanted/1"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">What do I do to make evolution sync with a Visor PDA?</FONT></H3>
Tue, 29 Oct 2002 08:18:05 -0700
<BR>Michael Havens (<a href="mailto:linux-questions-only@ssc.com?cc=bmike1@vei.net&subject=%20Re%3A%20%5BLG%2085%5D%20help%20wanted%20%231">bmike1 from vei.net</a>)
<!-- sig -->
<!-- sig -->
<P><STRONG>
Is it possible? Another forums told me that it was! They told me it was
yet it will not. Whenever a sync is attempted the PDA tells me that a
connection "could not be established". What could I download in it's
stead that I don't have to fiddle-faddle with? Perhaps it isn't reading
the USB correctly. If I open the hardware browserand click 'USB Devices'
it gives me a manufacturer and a driver (usb-uhci) but no device. Any
help you can give me would be very much appreciated. Once I learn more
how would I go about joining your team? I want to help others later who
are in the same predicament that I am now
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)"
height="24" width="20" align="middle">
</STRONG></P>
<blockquote><font color="#000066">Cool. Anybody who wants to be helpful is welcome to join; see
<A HREF="../tag/members-faq.html"
>http://www.linuxgazette.com/tag/members-faq.html</A>. I'll add that a
cheery sense of humor is a plus.
-- Heather</font></blockquote>
<P><STRONG>
One last thing, do I have to uninstall anything like in Windows? If I
remember correctly the answer is 'no' but I best make sure before I erase
any programs.
</STRONG></P>
<P><STRONG>
I'm running RedHat 7.3 with a <A HREF="http://www.kde.org/">KDE</A> desktop (did I phrase that correctly?).
</STRONG></P>
<P><STRONG>
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)"
height="24" width="20" align="middle"> ~Mike~ (-:
</STRONG></P>
<blockquote><font color="#000066">Yes, you did. It might be handy to know a kernel version, but we can
guess you have the stock one that came with Red Hat 7.3.
-- Heather</font></blockquote>
<P><STRONG>
Oops, one more question. When do you release the monthly editions of
your web magazine? If you already covered these issues in previous editions
just refering me to the edition's URL would work.
</STRONG></P>
<blockquote><font color="#001F3F">Linux Gazette is published on the first of the month at midnight (UTC-0800).
Sometimes it's a few hours late (as one smart alec in Australia noticed at 12:15am on
the millenium New Year in 2000
<IMG ALT=":)" SRC="../gx/dennis/smily.gif" WIDTH="20" HEIGHT="24">
), but that's the goal.
-- Mike</font></blockquote>
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<P> <A NAME="wanted/2"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">Redhat 7.1 freezes often</FONT></H3>
09 Nov 2002 13:59:46 +0000
<BR>Rajaraman (<a href="mailto:linux-questions-only@ssc.com?cc=rajachemist@yahoo.com&subject=%20Re%3A%20%5BLG%2085%5D%20help%20wanted%20%232">rajachemist from yahoo.com</a>)
<!-- sig -->
<P>
Hi,
</P>
<P>
My computer version is redhat 7.1.I had two xeon
processors inside. (8*512GHz) I am using gnome as my
window manager.
</P>
<P>
It frezees randomly (like once a week or twice or thrice)
and I can not do anything other than use the power swtich
to reboot it though mouse is moving but it is not doing
anything on the screen. Hardaware diganstic test, I did
with a CD sayhing that there is no error.
</P>
<P>
I though it would be a temperature problem,but in UK
the temperature is not so hot and there are six fan
inside the cpu.I put an extra fan as well, it does not
help.
</P>
<P>
I have used the cpu memory and tempertaute controller
in linux to monitor the temp. chnages but it reveale
normal temperture. I have not got any clue and why. I
consult some body but most of the people are unware
about the OS and the problems.
</P>
<P>
SO it would be helpful If you could tell me
sugesstions and ideas.
</P>
<P>
regards
<BR>rajaraman
</P>
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<P> <A NAME="wanted/3"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">How can i determine IP address of client?</FONT></H3>
Thu, 07 Nov 2002 13:53:06 -0600
<BR>Dave Nissman (<a href="mailto:linux-questions-only@ssc.com?cc=answerguy@ssc.com&cc=daven@web-wise.com&subject=%20Re%3A%20%5BLG%2085%5D%20help%20wanted%20%233">daven from web-wise.com</a>)
<!-- sig -->
<!-- sig -->
<P>
I have a linux server and for various reasons I have processes telneting
in. I need to identify the ip address of the client fron within a c
program running in the telnet session
</P>
<blockQuote><ol>
<LI>so i can tell the client his ip address from application
<LI>so ican limit what that node can do.
</ol></blockQuote>
<P>
Any thoughts Thanks in advance
</P>
<!-- end 3 -->
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<P> <A NAME="wanted/4"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">Question</FONT></H3>
Wed, 6 Nov 2002 16:22:13 -0500
<BR>Antony Gordon (<a href="mailto:linux-questions-only@ssc.com?cc=answerguy@ssc.com&cc=agordon@bkbacademy.org&subject=%20Re%3A%20%5BLG%2085%5D%20help%20wanted%20%234">agordon from bkbacademy.org</a>)
<!-- sig -->
<!-- sig -->
<P><STRONG>
Hi,
</STRONG></P>
<P><STRONG>
My manager wants me to setup the network so that based on userid and IP
address (more so userid) you can print anywhere in the building, or just to
the printer in the room. I am doing this at a school. Any ideas as to how
that can be accomplished?
</STRONG></P>
<P><STRONG>
TIA,
-Tony
</STRONG></P>
<BLOCKQUOTE>
[David Mandala]
Really need more information in order to answer your question. What
types of computers are on the network, what types of print servers, etc.
</BLOCKQUOTE>
<BLOCKQUOTE>
Cheers
</BLOCKQUOTE>
<P><STRONG>
The network consists of a server (RH 7.3) with about 50 ThinkNICs (diskless
workstations) booting via PXE into Linux. The printers consist of HP
DeskJets in the classroom hooked to JetDirect boxes, a LJ 4100 DTN with JD
built in, and a Xerox Document Centre 425.
</STRONG></P>
<!-- end 4 -->
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<P> <A NAME="wanted/5"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">glibc versioning</FONT></H3>
31 Oct 2002 15:27:11 +0000
<BR>mike (<a href="mailto:linux-questions-only@ssc.com?cc=mike@redtux.demon.co.uk&subject=%20Re%3A%20%5BLG%2085%5D%20help%20wanted%20%235">mike from redtux.demon.co.uk</a>)
<!-- sig -->
<P>
Does anyone know if it is possible to compile against a specific glibc
version
</P>
<P>
To be clearer, I have glibc-2.2.93 installed which contains versions up
to and including 2.3
</P>
<P>
What I am trying to do is set up a build system for producing RPM's that
will work on RH 7.3 setups (which is 2.2.5)
</P>
<!-- end 5 -->
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<P> <A NAME="wanted/6"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">Alan Turing</FONT></H3>
Wed, 27 Nov 2002 11:10:52 -0000
<BR>Shane (<a href="mailto:linux-questions-only@ssc.com?cc=shane@hairyfred.freewire.co.uk&subject=%20Re%3A%20%5BLG%2085%5D%20help%20wanted%20%236">shane from hairyfred.freewire.co.uk</a>)
<!-- sig -->
<!-- sig -->
<P>
Hi Linux gang,
I am a fairly recent convert to Linux, I am currently running
a Win98 (boo hiss) and Redhat 7.2 dual boot system.
</P>
<P>
I wonder if you could help me?
After delving through your back issues I came to number 75 and
part one of a very interesting article about Alan Turing.
What happened to part 2?
Regards and thankyou for the magazine.
Shane Doveton.
(Scarborough, England).
</P>
<blockquote><font color="#001F3F">The author, G James Jones, has health
problems and was unable to complete the series. However, the good news is his
health is now better and he's started working again on the second part. I for
one really appreciate his articles because they are so readable and make the
history come alive, and readers have also sent in a significant amount of
positive feedback too.
</font></blockquote>
<blockquote><font color="#001F3F">If anybody else would like to write some
articles about the giants in computer science history, we'd be interested in
publishing them.
-- Mike</font></blockquote>
<!-- end 6 -->
<HR>
<center>
<BIG><STRONG><FONT COLOR="maroon">GENERAL MAIL</FONT></STRONG></BIG>
<BR>
</center><HR>
<UL>
<!-- index_text begins -->
<li><A HREF="#mailbag/1"
><strong>Great info</strong></a>
<li><A HREF="#mailbag/2"
><strong>etymology of "daemon"</strong></a>
<li><A HREF="#mailbag/3"
><strong>virtual beer and feature request</strong></a>
<li><A HREF="#mailbag/4"
><strong>Hoping... Recovered, THANKS!</strong></a>
<!-- index_text ends -->
</UL>
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="mailbag/1"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">Great info</FONT></H3>
Sun, 24 Nov 2002 09:29:42 -0700
<BR>lucifersam (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2085%5D%20mailbag%20%231">lucifersam from shaw.ca</a>)
<!-- sig -->
<!-- sig -->
<P>
I realy enjoy finding new ways to code something with examples that actualy
work!
</P>
<P>
This notion came to me after I found the artical on "Adding Plugin
Capabilities To Your Code" By Tom Bradley. Except for a implicit cast and
some missing header file includes, the code worked like a charm.
</P>
<P>
I usualy find it difficult to find code that does what it says it does and
is in a simple an understandable fasion. I have been impressed. I
expect (read hope) to see more of this in the rest of your issues!
</P>
<P>
Thanks.
</P>
<!-- sig -->
<!-- end 1 -->
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<P> <A NAME="mailbag/2"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">etymology of "daemon"</FONT></H3>
Mon, 18 Nov 2002 09:40:52 -0800
<BR>Bob Krovatz (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2085%5D%20mailbag%20%232">krovetz from nec-labs.com</a>)
<!-- sig -->
<!-- sig -->
<P><STRONG>
Hi Heather,
</STRONG></P>
<P><STRONG>
The use of daemon/demon in Operating Systems goes back to
the early 1960's. I did some further checking on the web and
found that it was used by the team at Project MAC around 1963
(see <A HREF="http://ei.cs.vt.edu/~history/Daemon.html"
>http://ei.cs.vt.edu/~history/Daemon.html</A>). On that web page
Fenando Corbato attributes the inspiration to Maxwell's daemons.
He says "Maxwell's daemon was an imaginary agent which helped
sort molecules of different speeds and worked tirelessly in
the background. We fancifully began to use the word daemon to
describe background processes which worked tirelessly to perform
system chores.". There is also a notion of "demon" in Artificial
Intelligence; that was where I heard about the etymology from
Selfridge's paper from 1958. I thought that Selfridge's work
inspired their use in operating systems (since his paper was
so early), but I should have done some more checking. In any
case the concept of "daemon" in operating systems predates
BSD by some time.
</STRONG></P>
<P><STRONG>
Bob
</STRONG></P>
<P>
Thanks for the extra effort to chase that down. It's cool to learn
about these things! Forwarding to the Answer Gang so they get to
see it, and so I can get it added into The Mailbag for this month.
</P>
<P>
Have a great day
</P>
<!-- sig -->
<!-- sig -->
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<P> <A NAME="mailbag/3"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">virtual beer and feature request</FONT></H3>
Wed, 6 Nov 2002 07:04:17 -0800 (PST)
<BR>Raj Shekhar (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2085%5D%20mailbag%20%233">lunatech3007 from yahoo.com</a>)
<!-- sig -->
<!-- sig -->
<P><STRONG>
Hi folks!
This letter has some feature requests, some tips
and lots of virtual beer.
</STRONG></P>
<P><STRONG>
Heather &amp; Mike
</STRONG></P>
<blockquote><STRONG>
LG# 84 was great, awesome, cool!Keep
up the good work
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)"
height="24" width="20" align="middle">.
</STRONG></blockquote>
<P><STRONG>
Heather
</STRONG></P>
<blockquote><STRONG>
Your list of Do's and Dont's was really
in the spirit of Linux. Enjoyed it and
have copied it
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)"
height="24" width="20" align="middle">
</STRONG></blockquote>
<P><STRONG>
Ashwin
</STRONG></P>
<blockquote><STRONG>
Thanks for the tip on using Konqueror for
<BR>reading info pages.
</blockquote></STRONG></P>
<P><STRONG>
Ben
</STRONG></P>
<blockquote><STRONG>
Thanks for the tips on whatis,whereis.
It seems you have something against
info. I find it(info) good.
</STRONG></blockquote>
<P><STRONG>
Michael Conry
</STRONG></P>
<blockquote><STRONG>
Your News Byte
"Venezuela and Other Government News"
in LG#83 helped me a lot in writing a
paper on using Free Software in
egovernance in India. Your selection
of sites for News Byte is always
wonderful.
</STRONG></blockquote>
<P><STRONG>
And now a "Feature Request"
I use a cyber cafe to download TWDT(HTML) for LG.
Earlier you included author bio with the article
itself.
</STRONG></P>
<P><STRONG>
Can it be possible to append the author bio to the
TWDT file. Or maybe make a TWDT for the author bio
itself for each issue.
I really enjoyed reading the bios
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)"
height="24" width="20" align="middle">.
</STRONG></P>
<P><STRONG>
I have sent my tip to TAG
</STRONG></P>
<P><STRONG>
May the great gnu have mercy on your soul!
</STRONG></P>
<p><strong>
<br>Raj Shekhar
</strong></p>
<blockquote><font color="#000066">We've shared the kudos around to everybody, and I restocked the TAG fridge
with your v-beer. Glad you're enjoying the 'zine.
-- Heather</font></blockquote>
<blockquote><font color="#001F3F">(regarding bios in TWDT) We'll think about this. One of the purposes of
the Author pages is to have the latest contact information and bio; the
articles and TWDT would not be changed after publication.
</font></blockquote>
<blockquote><font color="#001F3F">Pehaps I can put the entire bio page (minus the links to previous articles,
and minus the large type in the header) at the bottom of the TWDT article,
with a note that this information may be old and another link to the
Author page.
-- Mike</font></blockquote>
<!-- end 3 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="mailbag/4"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">Hoping... Recovered, THANKS!</FONT></H3>
Tue, 29 Oct 2002 10:02:48 -0500
<BR>Lon Diffenderfer (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2085%5D%20mailbag%20%234">profitrocket from nmax.net</a>)
<!-- sig -->
<blockquote><font color="#000066">An email thread occurred which was not linux, but about rescuing
documents in some oddball word processing format. A few of the Gang
gave it a shot.
-- Heather</font></blockquote>
<P><STRONG>
To all who replied, "THANK YOU!"
</STRONG></P>
<P><STRONG>
With the information you provided, I was able to find a local professional
who had administered Xenix systems in years past and was able to use
"strings" to recover the data. I still do not understand exactly what he
did, but I am elated and very grateful to your group for your assistance. If
this is the kind of help I can get for Linux, maybe it's time to learn it
and switch.
</STRONG></P>
<BLOCKQUOTE>
[Jay R. Ashworth]
Probably.
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)"
height="24" width="20" align="middle">
</BLOCKQUOTE>
<BLOCKQUOTE>
Outstanding; glad to ehar you got your data back. Now you understand
why Unix people (and especially Linux people) are fond of textual
configuration and data files whenever possible...
</BLOCKQUOTE>
<BLOCKQUOTE>
What he <EM>did</EM> was to use the Unix strings(1) program, which sifts
through a [random] file looking for strings of characters that appear
to be ASCII text, extracting them from the surrounding (binary) data,
and printing them on it's output. Once you do that, it's usually just
a cleanup pass.
</BLOCKQUOTE>
<BLOCKQUOTE>
[Thomas Adam]
You're welcome!!!
</BLOCKQUOTE>
<BLOCKQUOTE>
I'm glad that people such as Jay, and myself, were of
some use. Makes a change actually!!
</BLOCKQUOTE>
<BLOCKQUOTE>
He he....
</BLOCKQUOTE>
<!-- end 4 -->
<HR>
<center>
<BIG><STRONG><FONT COLOR="maroon">GAZETTE MATTERS</FONT></STRONG></BIG>
<BR>
</center><HR>
<UL>
<!-- index_text begins -->
<li><A HREF="#gaz/1"
><strong>Hey answer guy.</strong></a>
<li><A HREF="#gaz/2"
><strong>Z for South, A for Africa</strong></a>
<!-- index_text ends -->
</UL>
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="gaz/1"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">Hey answer guy.</FONT></H3>
Wed, 13 Nov 2002 21:28:19 -0800
<BR>Rick Moen (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2085%5D%20gazette%20matters%20%231">the <em>LG</em> Answer Gang</a>)
<blockquote><font color="#000066">Once upon an email, a good question came in. Too bad it had one of
those automatic confidentiality notes attached. Darn. The Answer Gang
(I don't recall who at the moment) sent the fellow a little note,
suggesting that we can help him if he attaches counter-disclaimers,
or gives us permission. We could make him anonymous, of course.
</font></blockquote>
<blockquote><font color="#000066">He replied with a short, brusque note saying he found the answer elsewhere.
Whose exact text, of course, we can't repeat
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle">
-- Heather</font></blockquote>
<BLOCKQUOTE>
[Rick Moen]
Don't worry, we know what you <EM>really</EM> meant by that rather
graceless, if not arrogant, comment: You meant "Er, sorry about failing
to compensate for a dumb disclaimer that defeats the purpose of your
group entirely, and if deliberate would have suggested that I don't
value what you do. I'll make sure I don't do it in the future."
</BLOCKQUOTE>
<BLOCKQUOTE>
We understand that sometimes you just don't say what you mean, and we
hear the intended message, anyway.
</BLOCKQUOTE>
<BLOCKQUOTE>
[Robos]
Hi Rick. I normally don't post on <TT>/.</TT> but I read this there quite often and
somehow this also applies in your case:
</BLOCKQUOTE>
<h4 align="center"><br>PLEASE MOD PARENT UP!
</h4>
<BLOCKQUOTE>
<IMG SRC="../gx/dennis/smily.gif" ALT=";-)"
height="24" width="20" align="middle">
How about in school, teaching the kids to have some manners and we all
might get along more nicely...
</BLOCKQUOTE>
<!-- end 1 -->
<!-- . . . . . . . . . . . . . . . . . . . -->
<HR WIDTH="40%" ALIGN="center">
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">Z for South, A for Africa</FONT></H3>
Fri, 8 Nov 2002 10:07:51 -0800
<BR>Richard Meyer (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2085%5D%20gazette%20matters%20%232">meyerri from au1.ibm.com</a>)
<BR>and Chris Duncombe Rae (<a href="mailto:linux-questions-only@ssc.com?subject=%20Re%3A%20%5BLG%2085%5D%20gazette%20matters%20%232">duncombe from ring.wcape.gov.za</a>)
<!-- sig -->
<!-- sig -->
<P><STRONG>
[Richard Meyer]
Hi Heather,
</STRONG></P>
<P><STRONG>
Just a minor correction on the advice you gave the laddie asking about
Net2Phone. The .za is South Africa's TLD. In case you're interested (and
I admit that you may not be), in the 19th century the Afrikaners used to
call South Africa, Zuid Afrika in the Dutch-descended Afrikaans. So that's
where SA becomes ZA, leaving SA for Saudi Arabia? (I think).
</STRONG></P>
<blockquote><font color="#001F3F">Funny, I though we did publish a correction about that in the same Mailbag
item. It must have been a letter that came in after publication.
-- Mike</font></blockquote>
<P><STRONG>
Keep up the good work with the Gazette.
</STRONG></P>
<blockquote><font color="#000066">Thanks
<IMG SRC="../gx/dennis/smily.gif" ALT="8)"
height="24" width="20" align="middle">. Mike's right, of course:
-- Heather</font></blockquote>
<BLOCKQUOTE>
[Chris Duncombe Rae]
First off, ZA is South Africa's country code; Zambia is ZM.
</BLOCKQUOTE>
<blockquote><font color="#000066">...but the corrector had more important news than that I forgot to
look up the ISO codes before going to press.
-- Heather</font></blockquote>
<BLOCKQUOTE>
[Chris]
The <A HREF="http://www.linux.org.za/LDP"
>http://www.linux.org.za/LDP</A> URL leads nowhere. Hunting and
pecking around from <A HREF="http://www.linux.org.za"
>http://www.linux.org.za</A> leads to some HOWTOs
and more dead links. Speaking as one who also suffers bandwidth
limitations I'd prefer to be pointed directly at the Linux Documentation
Project than have to scratch around a supposedly closer site fruitlessly.
</BLOCKQUOTE>
<BLOCKQUOTE>
Second, I've had a look at your mirror sites in South Africa and a lot of
them are very stale.
</BLOCKQUOTE>
<blockquote><font color="#000066">Of the ones he tried two lead to mirrors that are more than 2 years stale,
one may be alive but having connection problems, and others were dead.
-- Heather</font></blockquote>
<BLOCKQUOTE>
[Chris]
Time to update your mirror site list? Or maybe everyone turned
off their sites as well as their mirrors while you were upgrading
yours?
</BLOCKQUOTE>
<blockquote><font color="#001F3F">I wrote to www.linux.org.za to see if they plan to reinstate their mirror.
For the others, I'll check again in a couple weeks and if they're still
down I'll delete the listings.
</font></blockquote>
<blockquote><font color="#001F3F">We don't get feedback when mirrors go down unless somebody tells us, and we
don't have the time to check 210 mirrors manually. I have looked into writing
an automatic mirror checker or finding one off the shelf, but haven't found
anything satisfactory yet, anything that can deal with timeout errors on 200
sites, do retries, and report problems back to a program in a way it can take
action.
-- Mike</font></blockquote>
<blockquote><font color="#000066">Folks, if you are running one of our listed mirrors and decide you can't
handle the bandwidth anymore, take it private, or otherwise aren't going
to mirror visibly... Please, take a spare moment, and let us know that
you're leaving the mirror system; we'll be glad to take all the extra
visitors back off your shoulders. Our blessings to you for what you
<EM>could</EM> provide aren't any less when you can't any longer.
</font></blockquote>
<blockquote><font color="#000066">Also, new mirrors are always welcome
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle">
-- Heather</font></blockquote>
<!-- end 2 -->
<P> <hr> </p>
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
<h5>This page edited and maintained by the Editors of <I>Linux Gazette</I><br>HTML script maintained by <A HREF="mailto:star@starshine.org">Heather Stern</a> of Starshine Technical Services, <A HREF="http://www.starshine.org/">http://www.starshine.org/</A>
<br>Copyright &copy; 2002
<br>Copying license <A HREF="http://www.linuxgazette.com/copying.html">http://www.linuxgazette.com/copying.html</A>
<BR>Published in Issue 85 of <i>Linux Gazette</i>, December 2002</H5>
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WIDTH="200" HEIGHT="41" border="0"></A>
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD>
<center>
<BIG><BIG><STRONG><FONT COLOR="maroon">More 2&cent; Tips!</FONT></STRONG></BIG></BIG><BR>
<!-- BEGIN tips -->
<STRONG>By <A HREF="mailto:linux-questions-only@ssc.com">The Readers of <i>Linux Gazette</I></A></STRONG></BIG>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<center><STRONG>See also: The Answer Gang's
<a href="../tag/kb.html">Knowledge Base</a>
and the <i>LG</i>
<a href="http://www.linuxgazette.com/search.html">Search Engine</a></STRONG>
</center><HR>
<UL>
<!-- index_text begins -->
<li><A HREF="#tips/1"
><strong>Linux now serving: Outlook Global Address List</strong></a>
<li><A HREF="#tips/2"
><strong>no more duplicate email</strong></a>
<li><A HREF="#tips/3"
><strong>Changeing IP address</strong></a>
<li><A HREF="#tips/4"
></a>linux consoles --or--
<br><A HREF="#tips/4"
><strong>The "Other" [Alt] Key</strong></a>
<li><A HREF="#tips/5"
><strong>how to create Imakefiles</strong></a>
<li><A HREF="#tips/6"
></a>Booting stops at devfs --or--
<br><A HREF="#tips/6"
><strong>Even journalled filesystems need fsck sometimes</strong></a>
<li><A HREF="#tips/7"
><strong>Foxpro</strong></a>
<li><A HREF="#tips/8"
><strong>unable to open an initial console</strong></a>
<li><A HREF="#tips/9"
></a>question on redhat ip forwarding --or--
<br><A HREF="#tips/9"
><strong>IP Masquerading: Red Hat 8.x Redoux</strong></a>
<li><A HREF="#tips/10"
><strong>Learning Red Hat 8.0</strong></a>
<li><A HREF="#tips/11"
><strong>Q: man pages for poll_wait(), wait_event() and others</strong></a>
<li><A HREF="#tips/12"
><strong>is the md5 check always right?</strong></a>
<li><A HREF="#tips/13"
><strong>Follow ups on mgp and mplayer</strong></a>
<li><A HREF="#tips/14"
><strong>Net2Phone ipchains config</strong></a>
<li><A HREF="#tips/15"
><strong>Lost win95 data (and system) when loading linux</strong></a>
<li><A HREF="#tips/16"
><strong>Good locations for sendmail howtos?</strong></a>
<li><A HREF="#tips/17"
></a>internet connection --or--
<br><A HREF="#tips/17"
><strong>Will this modem even work? Let's ask the internet</strong></a>
<li><I>Linux Journal's</I> Weekly News Notes
<a href="#tips/lj">Tech Tips</a>
<ul>
<li><A HREF="http://www.linuxjournal.com/modules.php?op=modload&name=NS-subscribe&file=newsletter"
>subscribe</A> to LJWNN
</ul>
<!-- index_text ends -->
</UL>
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="tips/1"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Linux now serving: Outlook Global Address List</FONT></H3>
Tue, 19 Nov 2002 11:59:58 -0800
<BR>Rick Moen (<a href="mailto:linux-questions-only@ssc.com?cc=LUIS@casiano.com&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%231%20ldap%20addresslist">the <em>LG</em> Answer Gang</a>)
<BR>Question by Luis Sanchez (LUIS from casiano.com)
<P><STRONG>
Is there a way to share the users in a Linux Mail Server for Outlook
clients? We will connect out Outlook clients via pop3/smtp to the
linux email server but wonder how to share the global address list
(like Exchange) ..
</STRONG></P>
<BLOCKQUOTE>
What you need to do is set up a shared address book using the OpenLDAP
server, an open-source facility for serving up Lightweight Directory
Access Protocol information to networks, that is routinely included in
Linux distributions. This needs to be done with some care on the
OpenLDAP end of things, because Micros*ft Outlook is unusually picky
about the LDAP schema. One hands-on guide to configuring the schema
is here:
</BLOCKQUOTE>
<BLOCKQUOTE><BLOCKQUOTE><code>
<A HREF="http://www.dclug.org.uk/archive-Nov00-May01/msg00253.html"
>http://www.dclug.org.uk/archive-Nov00-May01/msg00253.html</A>
</code></BLOCKQUOTE></BLOCKQUOTE>
<BLOCKQUOTE>
You can find one general guide to setting up LDAP (server end)
<EM>software</EM>, in the form of a set of lecture notes I wrote about LDAP, a
year or so ago:
</BLOCKQUOTE>
<BLOCKQUOTE><BLOCKQuote><code>
<A HREF="http://linuxmafia.com/~rick/lecture-notes/ldap"
>http://linuxmafia.com/~rick/lecture-notes/ldap</A>
</code></BLOCKQuote></BLOCKQUOTE>
<BLOCKQUOTE>
An example of how to set up the <EM>client</EM> (MS-Outlook) end of the problem
(at a university site) is here:
</BLOCKQUOTE>
<BLOCKQUOTE><BLOCKQuote><code>
<A HREF="http://www.cae.wisc.edu/fsg/info/mail/ldap_outlook.html"
>http://www.cae.wisc.edu/fsg/info/mail/ldap_outlook.html</A>
</code></BLOCKQuote></BLOCKQUOTE>
<BLOCKQUOTE>
Note that appending to the address book from MS-Outlook is not
supported (or desirable, actually).
</BLOCKQUOTE>
<BLOCKQUOTE>
Good luck with the project. Expect it to take a while, to work out all
the details.
</BLOCKQUOTE>
<!-- end 1 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="tips/2"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">no more duplicate email</FONT></H3>
Tue, 29 Oct 2002 10:20:31 -0800
<BR>Dan Wilder (<a href="mailto:linux-questions-only@ssc.com&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%232%20dup%20email%20killer">SSC.COM sysadmin</a>)
<P>
We now keep an MD5 sum the body of every message submitted to the Answer
Gang. If another identical message body shows up, it gets sidelined.
</P>
<P>
As usual, this is run over procmail, with two stanzas in the
list's procmailrc that look like:
</P>
<p align="center">See attached <tt><a href="misc/tips/dupekiller.procmail.txt">dupekiller.procmail.txt</a></tt></p>
<P>
The first stanza says "filter this message through a program".
</P>
<P>
The second says "sideline if you see an X-Duplicate header in
the result".
</P>
<P>
The duplicate elimination script being used on this list
has been upgraded to use Python's library md5 routines
rather than an external pipeline, and to employ locking
on the db.
</P>
<P>
By popular request, we're now filtering other lists here with
this, and one local user who often receives duplicate emails
that are not always spams has asked for the script, too.
</P>
<P>
The upgraded script, which the procmail recipe calls upon:
</P>
<p align="center">See attached <tt><a href="misc/tips/dup.py.txt">dup.py.txt</a></tt></p>
<!-- end 2 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="tips/3"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Changeing IP address</FONT></H3>
Fri, 22 Nov 2002 07:22:58 +0530
<BR>Kapil Hari Paranjape (<a href="mailto:linux-questions-only@ssc.com?cc=eyal_kornblut@mod.gov.il&cc=kapil@imsc.res.in&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%233%20change%20IP">kapil from imsc.res.in</a>)
<BR>Question by eyal (eyal_kornblut from mod.gov.il)
<P><STRONG>
I have a Linux server that functions as a Mail Relay in my system.
All I want to do is to change its IP address.
How shuld I do it ? witch files shuld I change, and how ??
</STRONG></P>
<P><STRONG>
I would be very thanksfull for some help
</STRONG></P>
<P><STRONG>
eyal
</STRONG></P>
<P>
This depends quite a bit on the precise distribution of Linux you have
installed. Is it RedHat, <A HREF="http://www.debian.org/">Debian</A>, <A HREF="http://www.suse.com/">SuSE</A>, Mandrake,...
</P>
<P>
It also depends on how your network is configured. By static addresses
entered in some file under <TT>/etc</TT> or via DHCP.
</P>
<P>
At the very least you should do:
</P>
<P><CODE>
grep -ril "your_current_ip_address_here" /etc
</CODE></P>
<P>
to find out which files refer to your IP address.
</P>
<P>
In addition if you use SSL and/or SSH you must go through the
configuration of these services and check that the new IP address is
reflected.
</P>
<P>
Having gone through this procedure more than once, I must warn you
that <EM>if</EM> you a free machine that can take the place of your mail
server then the easiest solution is to setup <EM>that</EM> machine as the new
mail server and switch off the old machine.
</P>
<P>
Regards,
<BR>Kapil.
</P>
<blockquote><font color="#000066">You might also want to check that reverse-resolution of DNS is updated
to reflect that your new host is attached to this IP address; it's
normally handled by the ISP who owns the IP block, so it's not stored
locally unless you have made special arrangements, and even if you have,
best to make sure they went through safely for both the old and new
address.
-- Heather</font></blockquote>
<!-- end 3 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="tips/4"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">The "Other" [Alt] Key</FONT></H3>
Mon, 18 Nov 2002 09:46:18 -0800
<BR>Jim Dennis (<a href="mailto:linux-questions-only@ssc.com?cc=gavitron@shaw.ca&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%234%20other%20alt">the <em>LG</em> Answer Guy</a>)
<BR>Question by The Gavitron (gavitron from shaw.ca)
<!-- ::
The "Other" [Alt] Key
~~~~~~~~~~~~~~~~~~~~~
:: -->
<P><STRONG>
<A HREF="../issue35/tag/magickeys.html"
>http://www.linuxgazette.com/issue35/tag/magickeys.html</A>
</STRONG></P>
<P><STRONG>
James,
</STRONG></P>
<P><STRONG>
Further to your technical article quoted above;
</STRONG></P>
<P><STRONG>
You explain that I can use the <TT>/other/</TT> alt key for
ttys 13-24, but in my case, I only want to use both
alt keys to switch between the same 12 ttys. Is it
possible to configure this? Would making tty24 a
symbolic link to tty12 accomplish it? I realise it's
been over 4 years since you wrote the original article,
but if you can still help, I would greatly appreciate
it.
</STRONG></P>
<P><STRONG>
Yours,
Gavin McDonald.
</STRONG></P>
<P>
You DON'T want to try symlinking those device files around.
</P>
<P>
Just use the 'loadkeys' utility to change your Linux console's
keymaps around to suit you tastes. You can start by reading the
following man pages: loadkeys(1), keymaps(5), dumpkeys(1), and
possibly showkey(1)
</P>
<P>
Then use 'dumpkeys' to dump a set of all the current key bindings.
Edit that (delete all the stuff you don't want to change) and
look for the section that looks something like this:
</P>
<p align="center">See attached <tt><a href="misc/tips/jimd.console-keymap-fragment-1.txt">jimd.console-keymap-fragment-1.txt</a></tt></p>
<P>
... and another section like:
</P>
<p align="center">See attached <tt><a href="misc/tips/jimd.console-keymap-fragment-2.txt">jimd.console-keymap-fragment-2.txt</a></tt></p>
<P>
Now simply change those to read:
</P>
<p align="center">See attached <tt><a href="misc/tips/jimd.console-keymap-fragment-otheralt.txt">jimd.console-keymap-fragment-otheralt.txt</a></tt></p>
<P>
Notice that all I'm doing is changing the Console_13 to Console_1
etc. (at the end of each line that begins with the word keycode).
</P>
<P>
Then simply pass that through the loadkeys command. In fact you
could take that last excerpt (as show between the &quot; and &quot; quotes
above) save it to a file --- <TT>/usr/local/etc/mykeymap.def</TT> --- for
example and add a line to your rc.local file to perform a simple:
</P>
<P><CODE>
loadkeys &lt; /usr/local/etc/mykeymap.def
</CODE></P>
<P>
... command.
</P>
<!-- end 4 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="tips/5"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">how to create Imakefiles</FONT></H3>
Fri, 08 Nov 2002 16:10:27 +0530 (IST)
<BR>Karl-Heinz Herrman (<a href="mailto:linux-questions-only@ssc.com?cc=Kirankumar.Pv@geind.ge.com&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%235%20Imakefiles">the <em>LG</em> Answer Gang</a>)
<BR>Question by Kirankumar Po (Kirankumar.Pv from geind.ge.com)
<P><STRONG>
plz excuse me for asking questions without your permission ,
</STRONG></P>
<P><STRONG>
now my question is ...........
</STRONG></P>
<P>
This group (answergang) is willing to answer questions related to the
operating system linux, so if you ask a question according to this little
help what to ask and how to ask it:
</P>
<BLOCKQuote><code>
<A HREF="../tag/ask-the-gang.html"
>http://www.linuxgazette.com/tag/ask-the-gang.html</A>
</code></BLOCKQuote>
<P>
you won't have to appologise for asking.
</P>
<P><STRONG>
"can we delete a file of a particular version ?"
if so how , if not what is the alternate for that
</STRONG></P>
<P>
Now this question is somewhat... broad. Yes, certainly linux has a version
management system, My preferred one is CVS. But unless you tell us what <EM>you</EM>
use if you use one we will have trouble guessing what might be appropriate in
your case.
</P>
<P><STRONG><CODE>
file name is test
</CODE></STRONG></P>
<P><STRONG>
test
1.1---1.2--1.3----1.4---1.5
</STRONG></P>
<P><STRONG>
i want to delete version 1.3 what is the command for that
and tell me the condition of 1.4
</STRONG></P>
<P>
For cvs this would be the command "admin" with flag "-o" for outdate.
</P>
<blockquote><pre>khh &gt; cvs -H admin
Usage: cvs admin [options] files...
[.......]
-o range Delete (outdate) specified range of revisions:
rev1::rev2 Between rev1 and rev2, excluding rev1 and rev2.
rev:: After rev on the same branch.
::rev Before rev on the same branch.
rev Just rev.
rev1:rev2 Between rev1 and rev2, including rev1 and rev2.
rev: rev and following revisions on the same branch.
:rev rev and previous revisions on the same branch.
</pre></blockquote>
<P>
Information on a particular version would be told by
cvs status or cvs log on the file with an additional "-r revnumber" if you
really are interested only in that particular version.
</p>
<!-- end 5 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="tips/6"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Even journalled filesystems need fsck sometimes</FONT></H3>
Mon, 18 Nov 2002 13:08:46 +0000 (GMT)
<BR>Thomas Adam (<a href="mailto:linux-questions-only@ssc.com?cc=tedlinux@inet.net.nz&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%236%20fsck%20journal">The <em>LG</em> Weekend Mechanic</a>)
<BR>Question by Trev (tedlinux from inet.net.nz)
<!-- ::
Even journalled filesystems need fsck sometimes
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:: -->
<P><STRONG>
Hi, love your Mag, and your doing a great job here.
</STRONG></P>
<BLOCKQUOTE>
[Thomas]
I know
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)"
height="24" width="20" align="middle"> I love the magazine too
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)"
height="24" width="20" align="middle">
</BLOCKQUOTE>
<P><STRONG>
My MDK 8.1, kernel 2.4.8.26-mdk system stops at
</STRONG></P>
<pre><strong>running DevFs deamon
invald operand:0000
CPU:0
EIP: .........
EFLAGS .........
eax .........
asi .........
ds .........
Process devfs pid 123
Stack: .........
CallTrace: .....
Code:
(Lots of letters and numbers)
</strong></pre>
<P><STRONG>
Is this a hardware problem ?
</STRONG></P>
<BLOCKQUOTE>
[Thomas]
Oh, it most certainly would suggest a hardware
problem. As I am sure you are aware the "dev fs" sets
up those hardware devices contained within "<TT>/dev</TT>" such
as soundcard, etc.
</BLOCKQUOTE>
<P><STRONG>
i have no problems in <A HREF="http://www.suse.com/">SuSE</A> or Win (SuSE
and Win on hda, MDK and some vfat partitions on hdb)
and i can mount
MDKs partitions (in rescue) ok.
</STRONG></P>
<P><STRONG>
I've had problems when booting with devfs twice, the
first time (some
weeks ago) it put it back to the old dev system, 10
to 15 boots back, it
put it back to the devfs system.
</STRONG></P>
<BLOCKQUOTE>
[Thomas]
I'm not certain but is the new way ("devfs") actually
a kernel module rather than it being "built-in" to the
kernel???
</BLOCKQUOTE>
<P><STRONG>
I tried rescue to rebuild devfs but not
knowing/finding any commands (no
man pages) i got nowhere, reiserfsck and e2fsck
found no problems, i
commented out pts from fstab but it made no
difference. I tried booting
with devfs=nomount but lilo would not recognize it,
not in lilo i guess.
</STRONG></P>
<BLOCKQUOTE>
[Thomas]
hmmm...the script "<TT>/dev/MAKEDEV</TT>" does some things, but
not what you're trying to do.
</BLOCKQUOTE>
<P><STRONG>
I had no luck with your DB or google.
</STRONG></P>
<P><STRONG>
Neither did I
<IMG SRC="../gx/dennis/unsmily.gif" ALT=":-("
height="24" width="20" align="middle">
</STRONG></P>
<HR width="10%" align="center"><P><STRONG>
Sorry for being slow getting back to you, only got
it going late last night
and read your email (and 450 others).
</STRONG></P>
<BLOCKQUOTE>
[Thomas]
Oh, that's ok. You actually read 450 consecutive
e-mails? Gosh -- hope you haven't got eye-strain
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)"
height="24" width="20" align="middle">
</BLOCKQUOTE>
<P><STRONG>
I changed the "devfs=mount" to "devfs=nomount" in
lilo.conf but it made no
difference,
</STRONG></P>
<BLOCKQUOTE>
[Thomas]
Hmm, that would suggest that your filesystem type for
the particular partition is abnormal in someway.
</BLOCKQUOTE>
<P><STRONG>
then out of desperation i tried
reiserfsck again on <TT>/</TT> but this
time i did reiserfsck --rebuild-tree and it fixed it
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)"
height="24" width="20" align="middle">, dmesg says "Mounted
devfs on <TT>/dev</TT>".
</STRONG></P>
<BLOCKQUOTE>
[Thomas]
Ah.... that's interesting and something that Mandrake
should have tested and/or implemented in both the
kernel and their documentation. I'm sure there are
other like you running MDK8.1 with the same problem/.
</BLOCKQUOTE>
<P><STRONG>
I'll see if devfs and reiserfs has an update for MDK
8.1.
</STRONG></P>
<BLOCKQUOTE>
[Thomas]
Unlikely -- you'll probably have to re-compile your
kernel as a result. But it's not as hard as you might
think....honest. Last I heard Eric Raymond was working
on a graphical "maze" frontend for compilation!!! So
much for the tcl/tk interface
<IMG SRC="../gx/dennis/unsmily.gif" ALT=":-("
height="24" width="20" align="middle">
</BLOCKQUOTE>
<BLOCKQUOTE>
[ashwin]
Linus rejected that for kernel 2.5. Instead, a Qt interface was chosen,
so that's what will be in 2.6 (or it may even be called 3.0).
</BLOCKQUOTE>
<P><STRONG>
Thanks Thomas for your reply.
</STRONG></P>
<BLOCKQUOTE>
[Thomas]
As I said -- it's what we're here for
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)"
height="24" width="20" align="middle">
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)"
height="24" width="20" align="middle"> Anytime.
If you have any other problems, let us know!
</BLOCKQUOTE>
<blockquote><font color="#000066">Gentle readers, it's also worth mentioning that journaled fs' will still
be fsck'd when the volumes reach their maximum mount count. Journals
make them robust, so a crash (which marks notmal filesystems "dirty",
forcing fsck) simply results in a journal replay. So now we know one
thing that can happen if the journal itself gets an ouchie.
-- Heather</font></blockquote>
<!-- end 6 -->
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<P> <A NAME="tips/7"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Foxpro</FONT></H3>
Sun, 17 Nov 2002 20:43:29 -0800
<BR>Rick Moen (<a href="mailto:linux-questions-only@ssc.com?cc=devi_ys@yahoo.com&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%237%20foxpro">the <em>LG</em> Answer Gang</a>)
<BR>Question by Deviyanti Setionegoro (devi_ys from yahoo.com)
<P><STRONG>
My name is Deviyanti, I want to ask a question, I have a foxpro 2.6
under dos that runs on windows NT. Now I want to migrate from windows
NT to linux Redhat 7.2. The question is will my application in foxpro
2.6 can run in Linux? If can, what are the additional software that I
should install first, before I move my aplication in foxpro 2.6 to
linux.
</STRONG></P>
<P>
Something called "Recital Linux Developer" runs FoxPro 2.6 applications
unchanged on Linux:
</P>
<BLOCKQuote><blockquote><code>
<A HREF="http://www.recital.com/solutions_foxpro.htm"
>http://www.recital.com/solutions_foxpro.htm</A>
</code></BLOCKQuote></blockquote>
<P>
Additionally, this question did sort of come up once before, a few years
back, when Answer Gang founder Jim Dennis was The Answer Guy, all by his
lonesome:
</P>
<blockquote><BLOCKQuote><code>
<A HREF="../issue30/tag_database.html"
>http://www.linuxgazette.com/issue30/tag_database.html</A>
</code></BLOCKQuote></blockquote>
<P>
Some of that will no doubt still be relevant.
</P>
<!-- end 7 -->
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<P> <A NAME="tips/8"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">unable to open an initial console</FONT></H3>
Fri, 08 Nov 2002 12:24:07 +0530 (IST)
<BR>Karl-Heinz Herrman (<a href="mailto:linux-questions-only@ssc.com?cc=lawrence.osullivan@141.com&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%238%20initial%20console">the <em>LG</em> Answer Gang</a>)
<BR>Question by Lawrence O'Sullivan (lawrence.osullivan from 141.com)
<P><STRONG>
Hi, I could sure use some help with this problem. I've followed the "Linux
from Scratch" guides to building a Linux system. Their instructions and
guides were very good, and everything seems to have compile correctly.
Also, I have posted this question on their support mail, and received
several suggestion but none helped. When I boot into the new Linux system,
the process hangs and the last three lines displayed are:
</STRONG></P>
<pre><strong>Freeing unused kernel memory: 140k freed
Warning: unable to open an initial console
Kernel Panic: Attempted to kill init
</strong></pre>
<P><STRONG>
Entering this lfs root=/dev/hda9 init=/bin/sh in lilo still hangs.
</STRONG></P>
<BLOCKQUOTE>
I'm pretty sure (since I had the same when I was first time switching from
2.2.x kernel to 2.4.x style) that the console driver is not in the kernel.
my config seems to have that as "y" not as module.
</BLOCKQUOTE>
<p align="center">See attached <tt><a href="misc/tips/k-h.kernel-dot-config-fragment.txt">k-h.kernel-dot-config-fragment.txt</a></tt></p>
<P><STRONG>
I'm not using devfs.
</STRONG></P>
<P><STRONG>
The inittab file appears correct, and was reviewed by the LFS folks.
</STRONG></P>
<P><STRONG>
The fstab file appears correct, and was reviewed by the LFS folks.
</STRONG></P>
<P><STRONG>
The configuration (.config) for the Kernel build appears to be correct. It was reviewed by the LFS folks and I compared it to the distribution that loads.
</STRONG></P>
<BLOCKQUOTE>
Maybe or maybe not -- make sure the above mentioned character devices are
there.
</BLOCKQUOTE>
<P><STRONG>
The new Linux system is on its own partition and the root and boot are on the same partition.
</STRONG></P>
<P><STRONG>
My original Linux distribution, which is on its own partition, still boots and can mount the partition with the new Linux system.
</STRONG></P>
<P><STRONG>
Any suggestion as to what else I can check or change would really help.
</STRONG></P>
<P><STRONG>
Thanks
<BR>Lawrence
</STRONG></P>
<!-- end 8 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="tips/9"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">IP Masquerading: Red Hat 8.x Redoux</FONT></H3>
Mon, 18 Nov 2002 20:55:34 -0800
<BR>Jim Dennis (<a href="mailto:linux-questions-only@ssc.com?cc=chhong@cisco.com&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%239%20ip%20masq%20rh%208">the <em>LG</em> Answer Guy</a>)
<BR>Question by chhong (chhong from cisco.com)
<!-- ::
IP Masquerading: <A HREF="http://www.redhat.com/">Red Hat</A> 8.x Redoux
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:: -->
<P><STRONG>
I have a RedHat Linux 8.0 machine with kernal 2.4.18-14. One of the
network card (Eth0 eg. 192.168.10.1) is connected to my private network
(consisting of a FTP server and 2 pc). Another network card (Eth1 eg.
201.1.1.*) is connected to the internet. How do I make my FTP server
accessible from other pcs in the internet and make pcs in my private
network access the internet?
</STRONG></P>
<P><STRONG>
Thanks
<BR>Chris Hong
</STRONG></P>
<P>
Well, I haven't played with Red Hat 8.0 yet. However, the key to
your question lies in two steps. First you have to enable the kernel's
packet forwarding feature. Manually this can be done via a command
like:
</P>
<blockquote><CODE>
echo 1 &gt; /proc/sys/net/ipv4/ip_forward
</CODE></blockquote>
<P>
However, that would not persist beyond a reboot. Under Red Hat there
is an <TT>/etc/sysctl.conf</TT> file which needs to have an entry like:
</P>
<BLOCKQuote><code>
net.ipv4.ip_forward = 1
</code></BLOCKQuote>
<P>
This allows the kernel to route packets (from your internal network
to the outside world).
</P>
<P>
However, that obviously won't do much good by itself. Packets from
your network that "leaked" out to the Internet would be useless since
no responses could get back to your RFC1918 non-routable addresses
(192.168.*.*, 10.*.*.*, and 172.16.*.* through 172.31.*.*).
</P>
<P>
So, the other requisite step is to enable IP masquerading. Over the
years the Linux IP packet filtering features haved changed radically
with each major kernel release. So old versions of Linux used the
'ipfw', then the 'ipfwadm', and then the 'ipchains' commands to manage
the kernel's packet filtering tables and configure its behavior. Red
Hat version 8.0 uses a 2.4 kernel with the netfilter subsystem and the
'iptables' command to manage it.
</P>
<blockquote><pre>modprobe iptable_nat
# In the NAT table (-t nat), Append a rule (-A) after routing
# (POSTROUTING) for all packets going out eth1 (-o eth1) which says to
# MASQUERADE the connection (-j MASQUERADE).
iptables -t nat -A POSTROUTING -o eth1 -j MASQUERADE
</pre></blockquote>
<blockQuote><ul>
<LI>Example slightly modified from
<A HREF="http://www.netfilter.org/documentation/HOWTO//NAT-HOWTO-4.html#ss4.1"
>http://www.netfilter.org/documentation/HOWTO//NAT-HOWTO-4.html#ss4.1</A>
</ul></blockQuote>
<P>
You may have to hunt around in the Red Hat <TT>/etc/</TT> directory tree to
figure out the best place to put his command. I think they have an
<TT>/etc/rc.d/init.d/iptables</TT> script which you can enable with their
'chkconfig' command. If you read that I think you'll find some file
like <TT>/etc/sysconfig/network-scripts/iptables.dat</TT> or something like
that. If I recall correctly from Red Hat 7.x, you could put just the
arguments for this iptables command (from the -t to the end of the line)
into that file.
</P>
<P>
The reason I'm tossing in so many qualifiers in this last paragraph is
because I mostly use <A HREF="http://www.debian.org/">Debian</A> and haven't actually installed or managed
a Red Hat 8.0 system, yet. In addition some of the details change with
every major release. The differences are minor --- easy to adapt to if
you can read simple shell scripts.
</P>
<P>
There is probably also a way to do all of this using some GUI tool.
However, I still avoid graphical system administration tools. I'm
firmly of the opinion that the most important systems administration
tool is your favorite text editor!
</P>
<!-- end 9 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="tips/10"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Learning Red Hat 8.0</FONT></H3>
Tue, 26 Nov 2002 13:40:35 -0800
<BR>Heather Stern (<a href="mailto:linux-questions-only@ssc.com?cc=jhavilan@attbi.com&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%2310%20learn%20redhat"><em>Linux Gazette</em> Technical Editor</a>)
<BR>Question by James M. Haviland (jhavilan from attbi.com)
<P><STRONG>
What is the best book to learn RH's 8.0? Or will the books I have on
learning 5 or 6 and maybe 7 be good enough to learn the basics or anything
except the fine points.
</STRONG></P>
<P>
Stuff about the bash shell will be pretty much the same.
</P>
<P>
Learning how to use a text editor will be pretty much the same.
</P>
<P>
Chances are that in a modern one the screen may look a little different
but it will likely be a little easier to read.
</P>
<P>
Anything showing screen shots walking you through the install will show
pictures only good for that exact version. You can read the chapter
anyway, as the basic steps of partitioning and answering network
questions will still be asked, but the screens will look different.
</P>
<P>
Pretty much, you can follow along in an older book, and look at man
pages or --help output from a program to catch up on some things that
may be new. If you also connect to the internet and surf to the home
pages of some software you are trying to learn, there may be discussion
forums and more things to read there.
</P>
<P>
And of course there's the Linux Documentation Project
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle"> (www.tldp.org)
</P>
<P>
Many of these things will be equally valid for red hat, or for other
linux distributions.
</P>
<P><STRONG>
I tried to use the e-mail program that came with it and I set it up wrong
some how so that I couldn't send e-mails. I was able to use Mozzarella or
Netscape's e-mail program.
</STRONG></P>
<P>
You have to connect to an internet provider before you can read emails.
Your system usually has to have an SMTP program (sendmail, or one of its
competitors) in order to send emails.
</P>
<P>
Mozarella, yum. You probably meant "mozilla" - the browser's firebreathing
dinosaur-like mascot.
</P>
<P>
Mozilla and netscape use the same code under the hood; they compose
SMTP messages and transmissions directly, rather than needing a local
server. Think of this as driving the mail up to the post office
yourself all the time instead of leaving it at your door for the postman
to pick up when he comes by every day for the mail.
</P>
<P><STRONG>
Thank you for your time.
</STRONG></P>
<P><STRONG>
Jim
</STRONG></P>
<P>
You're welcome.
</P>
<!-- end 10 -->
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<P> <A NAME="tips/11"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Q: man pages for poll_wait(), wait_event() and others</FONT></H3>
Mon, 4 Nov 2002 16:21:32 -0500 (EST)
<BR>Pradeep Padala (<a href="mailto:linux-questions-only@ssc.com?cc=vkarasik@ndsisrael.com&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%2311%20kernel%20functions">the <em>LG</em> Answer Gang</a>)
<BR>Question by Vitaly Karasik (vkarasik from ndsisrael.com)
<P><STRONG>
Are there any additional sources for manpages [we've checked
kernel-doc package, <A HREF="http://kernelnewbies.org/documents"
>http://kernelnewbies.org/documents</A>, Kernel*
HOWTO's and so on, but without success].
</STRONG></P>
<P>
Linux source is the authoritative documentation for kernel functions. I
guess you already know about <A HREF="http://lxr.linux.no"
>http://lxr.linux.no</A>. That's the right place
to look for documentation
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)"
height="24" width="20" align="middle">
</P>
<P>
Apart from that Alessandro Rubini's book on device drivers has some
information on this. Information regarding poll is here in that book:
</P>
<blockquote><BLOCKQuote><code>
<A HREF="http://www.xml.com/ldd/chapter/book/ch05.html#t3"
>http://www.xml.com/ldd/chapter/book/ch05.html#t3</A>
</code></BLOCKQuote></blockquote>
<P>
This should give a fair idea of what needs to be done when poll on a
device is done.
</P>
<P><DL><DT>
You can read the whole book online at:
<DD><A HREF="http://www.xml.com/ldd/chapter/book"
>http://www.xml.com/ldd/chapter/book</A>
</DL></P>
<P>
Also try to follow any driver's code which implements 'select' or 'poll'
for the device.
</P>
<!-- end 11 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="tips/12"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">is the md5 check always right?</FONT></H3>
Sun, 3 Nov 2002 18:23:17 +0000
<BR>Steve Kemp (<a href="mailto:linux-questions-only@ssc.com?cc=paupople@online.no&cc=skx@tardis.ed.ac.uk&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%2312%20md5sum">skx from tardis.ed.ac.uk</a>)
<BR>Question by Simon Pople (paupople from online.no)
<P><STRONG>
I just downloaded 3 Mandrake CDs via FTP and read after doing that that I
should have set the download mode to binary not ASCII. I didn't do that,
but when I run MD5 on all the .iso files they are all fine....is it possible
that even though the MD5 checksums are all matching, the files still aren't
correct, or is MD5 an infallible test of the downloaded ISOs?
</STRONG></P>
<P>
MD5 should be a good enough test of validity. It has got some weaknesses
which have recently come to light, but it's extremely unlikely that you've
come across three seperate examples.
</P>
<P>
It's probably the case that your FTP/download software switched to binary
by itself, without you having to explicitly do it.
</P>
<!-- end 12 -->
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<P> <A NAME="tips/13"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Follow ups on mgp and mplayer</FONT></H3>
Sun, 17 Nov 2002 03:40:22 +0100
<BR>Robos (<a href="mailto:linux-questions-only@ssc.com?cc=robos@muon.de&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%2313%20mgp%20and%20mplayer">the <em>LG</em> Answer Gang</a>)
<P>
Hi Folks
</P>
<P>
I did look into the mgp with embedded mplayer issue today again and got a
little further:
after looking into the man-page of xwininfo I found -name. If I call:
</P>
<BLOCKQuote><code>
xwininfo -name MagicPoint
</code></BLOCKQuote>
<P>
(always the same I hope
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle"> I get the win-id like this:
</P>
<blockquote><CODE>
xwininfo -name MagicPoint |grep Window |awk '{print $4}' &gt;/tmp/wid
</CODE></blockquote>
<P>
and then:
</P>
<BLOCKQuote><code>
mplayer /home/robos/movies/play* -vo x11 -wid cat /tmp/wid=1BOB
</code></BLOCKQuote>
<P>
OK, I actually put the whole calls into a bash script since mgp makes some
strange things if I call it from within mgp with %system. So, in the mgp
text I do a
</P>
<blockquote><code>
%system "/home/robos/mplayer.sh"
</code></blockquote>
<P>
and call the whole thing like this:
</P>
<blockquote><CODE>
mgp mplayer.mgp -x vflib -U
</CODE></blockquote>
<P>
The -U is the important one: -U since forking is prohibited
otherwise...
This sorta works, but the display stays a little garbled afterwards (I put a
%system "killall mplayer" on the next page) and in the page that displays
the vid nothing else is shown (no text). But, I would say something to
improve upon.
If you use -o with mgp it doesn't go fullscreen and then the vid is also
centered in my case (I use enlightenment btw).
</P>
<P>
OK
<br>I'll toy a little more
<br>Robos
</P>
<!-- end 13 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="tips/14"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Net2Phone ipchains config</FONT></H3>
Mon, 18 Nov 2002 11:46:27 -0600
<BR>John Larmour (<a href="mailto:linux-questions-only@ssc.com?cc=jlarmour@eds.com&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%2314%20net2phone">jlarmour from eds.com</a>)
<blockquote><font color="#000066">In last issue ( <EM>LG</EM> 84) help wanted #3:
<A HREF="../issue84/lg_mail.html#wanted/3"
>http://www.linuxgazette.com/issue84/lg_mail.html#wanted/3</A>
it was asked if Linux has net2phone support.
-- Heather</font></blockquote>
<P><STRONG>
I see that this request is a month or more old. Has this problem been
solved?
</STRONG></P>
<blockquote><font color="#000066">Many times, people do get their solutions, but don't pass them back
along to us. So I cannot really say.
-- Heather</font></blockquote>
<P><STRONG>
I have a linux firewall (ipchains) at home, and run Net2Phone on a
window98 box that goes through the firewall. If you are still having
problems, I may be able to help with some of the settings.
</STRONG></P>
<HR width="10%" align="center"><P><STRONG>
Okay, I'm at home now and can check the settings. On the Net2Phone
client, choose menu-&gt;preferences-&gt;network. Make note of the "doorman"
URLs and port numbers (mine are call1.net2phone.com and
call2.net2phone.com, both on port 6801). In the client box, choose a
number for your ports (I use the same for both TCP and UDP). Valid
numbers are greater than 1024 and less than 65000.
</STRONG></P>
<P><STRONG>
My firewall uses masquerading, and is not a proxy. I don't know what
your setup is, so this may or may not work for you. In my previous
message I said I use ipchains. Sorry, that shoud have been iptables. I
got it set up a while ago, and really haven't touched it since.
</STRONG></P>
<P><STRONG>
Here are the variables I use in my script:
</STRONG></P>
<pre><strong>${ISP} is the network card connected to my ISP,
${LAN} is the network card connected to my home network.
${PHINIT}is the port used by the doorman (6801)
${PHCTL} and ${PHVCE} are the TCP and UDP port numbers I picked
</strong></pre>
<P><STRONG>
Here are the iptables commands I added to my script to start my firewall:
</STRONG></P>
<pre><strong>iptables -A INPUT -p udp -i ${ISP}-s call1.net2phone.com -m state
--state != INVALID --source-port ${PHINIT} -j ACCEPT
iptables -A INPUT -p udp -i ${ISP}-s call2.net2phone.com -m state
--state != INVALID --source-port ${PHINIT} -j ACCEPT
iptables -A INPUT -p udp -i ${ISP}--source-port ${PHVCE} -j ACCEPT
iptables -A INPUT -p tcp -i ${ISP}--source-port ${PHCTL} -j ACCEPT
</strong></pre>
<P><STRONG>
Hope this isn't too late to be helpful....
</STRONG></P>
<!-- end 14 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="tips/15"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Lost win95 data (and system) when loading linux</FONT></H3>
Sun, 17 Nov 2002 13:00:20 EST
<BR>mike, Heather Stern (<a href="mailto:linux-questions-only@ssc.com?cc=JTHodgson@aol.com&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%2315%20lost%20partitions">the <em>LG</em> Answer Gang</a>)
<BR>Question by JTHodgson (JTHodgson from aol.com)
<P><STRONG>
Dear Answer gang - my problem is an inaccessible C: drive holding my win95
system and all my data - much of it not backed up, naturally
<IMG SRC="../gx/dennis/unsmily.gif" ALT=":-("
height="24" width="20" align="middle"> .
</STRONG></P>
<P><STRONG>
Here is how I think it happened.
</STRONG></P>
<P><STRONG>
I started with a standard Win95 set up, with a 5G C: drive, a bootable 48x cd
drive and a standard floppy a: drive.
</STRONG></P>
<P><STRONG>
I then added a 20G Western Digital secondary drive. This came with the
Phoenix bios overlay ez-bios, which took control of both internal drives
(despite the fact that c: was within the old bios limit).
</STRONG></P>
<P><STRONG>
With both drives running a single dos partition, the system ran without
problems, until I tried to partition the d: drive to load linux (6.3 suse).
Neither partition magic, nor fip would repartition the disk.
</STRONG></P>
<P><STRONG>
I then downloaded the latest data life guard (DLG) (=ez-bios) installation
utility from the web, and used it to partition the d: drive. I also made a
floppy win95 boot disk.
</STRONG></P>
<P><STRONG>
At this point the win95 system was operating correctly, but with a reduced
disk size visible on d:.
</STRONG></P>
<P><STRONG>
I then started to load linux by booting from the cd. It ran through the
initial screens without problem, but when it came to assigning the partition
to mount the system, the second partition on d: was not visible. There was
no escape route, so I powered off.
</STRONG></P>
<P><STRONG>
Now the system would not boot from c:.
</STRONG></P>
<P><STRONG>
Nor would it boot from the system disc in a:, or ,rather, when I did the c:
drive was not accessible (nor the d: drive!).
</STRONG></P>
<P><STRONG>
I tried fdisk <TT>/mbr</TT>, and restoring the mbr "before installing ez bios" and "
after installing ez-bios" (options in the downloaded DLG utility). The DLG
utility also told me that the c: drive had a "non dos partition".
</STRONG></P>
<P><STRONG>
I assume that I have inadvertently created a linux partition on the c: drive.
</STRONG></P>
<P><STRONG>
How can I recover from this? Or is there some other explanation? Is this a
</STRONG></P>
<P><STRONG>
diy job, or should I consider a data recovery service (my marriage may be at
stake here!).
</STRONG></P>
<P><STRONG>
Very grateful for any help you could give. I'm keen to join the penguins,
but this is off-putting!
</STRONG></P>
<P><STRONG>
John Hodgson
</STRONG></P>
<BLOCKQUOTE>
[mike]
First off, can you boot into linux?
If so check the data as follows
</BLOCKQUOTE>
<BLOCKQUOTE><BLOCKQUOTE><CODE>
mount the c: partition
</CODE></BLOCKQUOTE></BLOCKQUOTE>
<BLOCKQUOTE>
type ls <TT>/mnt</TT> to see if a mount point has been setup by your distro
</BLOCKQUOTE>
<BLOCKQUOTE>
if you see something like <TT>/mnt/dos_c</TT> do ls &lt;this dir&gt; to see if there
are any files
</BLOCKQUOTE>
<BLOCKQUOTE>
if there is no <TT>/mnt/dos</TT> etc directory do the following
</BLOCKQUOTE>
<blockquote><pre>mkdir /mnt/c
mount /dev/hda1 /mnt/c
</pre></blockquote>
<BLOCKQUOTE>
then type df to see what partitions are mounted
</BLOCKQUOTE>
<BLOCKQUOTE>
then type ls <TT>/mnt/c</TT> to see if your files are still there
</BLOCKQUOTE>
<P><STRONG>
Thanks, Mike...
</STRONG></P>
<P><STRONG>
To avoid the possibility of further over-writing on the old C: drive, I used
DemoLinux running from the CD drive. By default this loads the <A HREF="http://www.kde.org/">KDE</A> desk top.
</STRONG></P>
<P><STRONG>
This showed two internal drive icons, but clicking on hda1 gave an error:
</STRONG></P>
<Pre><STRONG>
"Unable to run the command specified. The file or directory file:/mnt/hda1
does not exist"
</STRONG></Pre>
<P><STRONG>
Moving to console mode:
</STRONG></P>
<P><STRONG>
ls /mnt gave the response
</STRONG></P>
<pre><strong>cdrom floppy hdb1
</strong></pre>
<P><STRONG>
Apparently the old C: drive is not being recognised
</STRONG></P>
<P><STRONG>
Mkdir <TT>/mnt/c</TT> gave error message
</STRONG></P>
<pre><strong>Mkdir cannot create directory '/mnt/c' : permission denied
</strong></pre>
<P><STRONG>
While DemoLinux was loading I spotted a line that I
think related to the old C: drive, giving it the following properties: win98
FAT-32 LBA-matched partition
</STRONG></P>
<BLOCKQUOTE>
[Heather]
Sorry to come a bit late to the game. Anyways it looks to me as if your
initial diagnosis is correct - the partition table has gotten somehow
mismatched with what is really on the drive.
</BLOCKQUOTE>
<BLOCKQUOTE>
The Linux utility to deal with this problem is gpart - it will
physically look at the bits on the drive, and guess a partition table
for you. If your drive electronics do not agree with what your BIOS
reads for cylinder/head/sector values, it might actually be wrong, but
if you see something that looks like the layout you remember, it's
probably right, and you can write the result into the MBR-tail with a
commandline switch.
</BLOCKQUOTE>
<BLOCKQUOTE>
(I say "tail" because strictly speaking the first 446 bytes are the boot
loader and the 64 bits at the end are the partition table, and some
techies refer to only the loader as the MBR, while others call the whole
512byte cluster this. But we digress.)
</BLOCKQUOTE>
<BLOCKQUOTE>
The DOS analogue to solve this problem - bearing in mind that I've not
had to use it for years, so I cannot vouch for the current edition
one way or another... is Symantec's Norton Disk Doctor... NDD <TT>/REBUILD.</TT>
As a few repartitioning utlities are on the market they might also have
some sort of "reset to whatever the disk has on it" feature - possibly
as a last-ditch rescue against their own failure modes. The same caveat
against the BIOS mismatch problem applies. Also, if it isn't new enough
a DOS tool may not recognize any linux bits you've managed to get on there.
</BLOCKQUOTE>
<BLOCKQUOTE>
Anyways, I <EM>have</EM> used gpart recently myself and can assure you that it
works. The real fun is getting a cd-boot or floppy-boot distro that
has it in there. I don't recall if I used Knoppix, or if I host-mounted
one of my laptop drives temporarily (so <TT>/dev/hda</TT> was a known good
system). DemoLinux, if it has a copy of gpart on it, can help you solve
that quite quickly, and if it doesn't have it, you may be able to fetch
a binary of the program into your ramdisk.
</BLOCKQUOTE>
<BLOCKQUOTE>
Pretty much, all the live-CD discs use a ramdisk or two.
</BLOCKQUOTE>
<!-- end 15 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="tips/16"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Good locations for sendmail howtos?</FONT></H3>
Tue, 26 Nov 2002 13:07:33 -0800
<BR>Heather Stern, John Karns (<a href="mailto:linux-questions-only@ssc.com?cc=supersimian@hotmail.com&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%2316%20sendmail%20howtos">the <em>LG</em> Answer Gang</a>)
<BR>Question by David (supersimian from hotmail.com)
<P><STRONG>
Hey there Answer Gang,
</STRONG></P>
<P><STRONG>
You've helped me in the past, I'm hoping you can help me again.
</STRONG></P>
<P><STRONG>
I'm having diffuculties setting up sendmail and friends on a small home
network. I can't seem to get mail to work between hosts. I feel fairly
competent in linux in general, but this continues to baffle me.
</STRONG></P>
<P><STRONG>
I'm using RedHat 8.0 on two systems, my main desktop, and our
firewall/dns/nat/etc box. My roommate is using WinXP. But basically, I'm
looking for a good howto doc on setting up email between the gateway box and
my desktop, so I can forward the root mail form the gateway to an arbitrary
account on my desktop. Y'know, for getting alerts, logwatch info, etc.
</STRONG></P>
<P><STRONG>
And just to learn a bit more about the workings of email in general.
</STRONG></P>
<P><STRONG>
At present, I can't get ANY kind of email to move between the two boxes.
</STRONG></P>
<P><STRONG>
Mostly, I'm looking for a really good writeup on how to configure things to
my liking. I mean, I don't want to have to buy a book on it, it's just for
home use, but I want a good understanding.
</STRONG></P>
<P><STRONG>
If you people can point me towards a good resource, I'd really appreciate
it.
</STRONG></P>
<BLOCKQUOTE>
[John Karns]
Well I suppose the best resource is the O'Reilly book on sendmail - but
since you mentioned that you don't want to buy a book, I do recall
stumbling across a helpful sendmail web site about 3 yrs ago. So a web
search would probably turn up a few sources of info. There are also some
fairly comprehensive FAQ's etc available...
</BLOCKQUOTE>
<BLOCKQUOTE>
[Heather]
</BLOCKQUOTE>
<blockQuote><ol>
<LI>try the faq's and other helpful notes at sendmail.org, then the
community forums at sendmail.net.
<LI>each of sendmail's major competitors also have websites; since some
of their FAQs are in the form of "under sendmail I would... how do I
do that in this mail transport?" then reading the documentation of
all the major mailers should help considerably toward learning about
email in general.
<LI>for your NT box to get mail from your linux server, either your linux
server needs to run POP or IMAP daemons... or your NT system has to
run an SMTP daemon and be listed as a MX for itself. The first one
is <EM>much</EM> easier.
</ol></blockQuote>
<P><STRONG>
Thanks Heather, I'll have a look at these resources.
Luckily, I've managed to muddle through a bit of it on my own,
the mail is moving, just need to fine-tune things a bit. I now
understand why the sendmail.cf file is so infamous
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle">
</STRONG></P>
<P><STRONG>
rewrite rules, UGH...
</STRONG></P>
<BLOCKQUOTE>
[John Karns]
Finally, I can provide a quick hint about (one method of) setting up mail
between hosts. For my purposes I just added the host names in
<TT>/etc/mail/mailertable</TT> in form of
</BLOCKQUOTE>
<BLOCKQUOTE>
machine1.my.psuedo.dom smtp:machine1.my.psuedo.dom
machine2.my.psuedo.dom smtp:machine2.my.psuedo.dom
</BLOCKQUOTE>
<BLOCKQUOTE>
In the comments in that file:
</BLOCKQUOTE>
<TABLE WIDTH="95%" BORDER="1" BGCOLOR="#FFFFCC"><TR><TD>
<p align="center">...............</p>
<BLOCKQUOTE><BLOCKQUOTE><CODE>
# sendmail will look for all non-local email into this file to determine
<BR># the transport way to the next host. the destination hostname is used
<BR># to find an entry in this file.
</CODE></BLOCKQUOTE></BLOCKQUOTE><p align="center">...............</p>
</TD></TR></TABLE>
<BLOCKQUOTE>
And from <TT>/etc/mail/README:</TT>
</BLOCKQUOTE>
<TABLE WIDTH="95%" BORDER="1" BGCOLOR="#FFFFCC"><TR><TD>
<p align="center">...............</p>
<BLOCKQUOTE>
sendmail.cf supports some more external database files. The
default configuration uses <TT>/etc/aliases</TT>, <TT>/etc/mail/mailertable</TT>,
<TT>/etc/mail/genericstable</TT> and <TT>/etc/mail/virtusertable.</TT> These files are
normal text files that are converted with "makemap" to the real database
files (ending in .db).
</BLOCKQUOTE>
<BLOCKQUOTE>
For all outgoing email, sendmail will use the destination hostname
and look into <TT>/etc/mail/mailertable</TT> to see how this email should
be transported to the next destination. Please read that file for
some examples on email-routing.
</BLOCKQUOTE><p align="center">...............</p>
</TD></TR></TABLE>
<BLOCKQUOTE>
Note 1: There is a Makefile in that dir to enable running 'make' after
adding the host names to the text file. That will create the .db file
which sendmail actually uses.
</BLOCKQUOTE>
<BLOCKQUOTE>
Note 2: I'm not sure how much of this structure is from the generic
sendmail and how much may be contributed by <A HREF="http://www.suse.com/">SuSE</A>, but my gueess is that it
is mostly generic. This seems to be born out by the above reference to
sendmail.cf pointing to those files.
</BLOCKQUOTE>
<BLOCKQUOTE>
Note 3: This setup works for me. I don't have a name server set up, just
use a hosts file. YMMV.
</BLOCKQUOTE>
<!-- end 16 -->
<!-- . . . . . . . . . . . . . . . . . . . -->
<HR WIDTH="40%" ALIGN="center">
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Will this modem even work? Let's ask the internet</FONT></H3>
Sun, 10 Nov 2002 14:15:06 -0800
<BR>Rick Moen (<a href="mailto:linux-questions-only@ssc.com?cc=ralphk@hauns.com&subject=%20Re%3A%20%5BLG%2085%5D%202c%20Tips%20%2317%20usb%20softmodem">the <em>LG</em> Answer Gang</a>)
<BR>Question by Helen &amp; Ralph (ralphk from hauns.com)
<!-- ::
Will this modem even work? Let's ask the internet
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:: -->
<P><STRONG>
can I use a zoom/modem usb model 3090 with redhat 7.2 ?
</STRONG></P>
<P>
The best place to research USB-hardware support problems in Linux is
<A HREF="http://www.linux-usb.org"
>http://www.linux-usb.org</A>. You might want to make a
note of that, for
the future. Selecting "Working devices list" on the front page takes
you the Overview page. From there, we select Devices, since we're
looking up support for a particular hardware device, rather than any of
the other information categories. We're now shown the dozen or so USB
device categories, and pick "Comm: Communications devices (Modems)".
This brings us to a long multipage list of modems by manufacturer.
Moving through that to the Zs, eventually finding the line item for
"Zoom Telephonics, Inc. 3090". Finally, selecting that item brings us
to <A HREF="http://www.qbik.ch/usb/devices/showdev.php?id=660"
>http://www.qbik.ch/usb/devices/showdev.php?id=660</A>.
</P>
<P>
And it's bad news:
</P>
<BLOCKQuote>
Zoom sales claims this is "a winmodem and will not
work with Linux". Shame.
</BLOCKQuote>
<P>
There's more, but that about sums it up:
This is undoubtedly a unit designed to achieve the lowest possible
retail price by omitting key circuitry normally integral to all modems
(the ROM or "controller" chip implementing required communications
protocols, and/or the UART chip to control and buffer serial
communications). The omitted functionality is then emulated in software
by MS-Windows-only proprietary "engine' software.
</P>
<P>
If/when you go shopping for a better modem, you might want to consult
Rob Clark's modem database, at
<A HREF="http://www.idir.net/~gromitkc/winmodem.html"
>http://www.idir.net/~gromitkc/winmodem.html</A>.
</P>
<blockquote><font color="#000066">The real tip here, for newbies and old hands alike; we can no longer
assume that being external or internal, or which interface a modem is
plugged into, indicates whether it has an incomplete chipset and needs
a booster shot from specialized driver software. Some manufacturers
offer fully-capable internal modems, and some external ones are duds
like this one. Use the net resources at <A HREF="http://www.linmodems.org"
>http://www.linmodems.org</A>,
and if you <EM>decide</EM> to use a supported or partially supported winmodem,
don't expect too much out of it when you have your system under a heavy
CPU load.
-- Heather</font></blockquote>
<!-- end 17 -->
<P> <hr> </p>
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
<h5>This page edited and maintained by the Editors of <I>Linux Gazette</I><br>HTML script maintained by <A HREF="mailto:star@starshine.org">Heather Stern</a> of Starshine Technical Services, <A HREF="http://www.starshine.org/">http://www.starshine.org/</A>
<br>Copyright &copy; 2002
<br>Copying license <A HREF="http://www.linuxgazette.com/copying.html">http://www.linuxgazette.com/copying.html</A>
<BR>Published in Issue 85 of <i>Linux Gazette</i>, December 2002</H5>
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
<HR>
<TABLE width="100%" BORDER><TR><TD WIDTH="200">
<A HREF="http://www.linuxgazette.com/">
<IMG ALT="LINUX GAZETTE" SRC="../gx/2002/lglogo_200x41.png"
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<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD>
<center>
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border="0" align="left">
<A NAME="answer"><BIG><BIG><STRONG><FONT COLOR="maroon"
>The Answer Gang</FONT></STRONG></BIG></BIG></a>
<img src="../gx/dennis/bbubble.gif" alt="(!)"
border="0" align="right"><BR>
<STRONG>By Jim Dennis, Ben Okopnik, Dan Wilder, Breen, Chris, and...
(<a href="tag/bios.html">meet the Gang</a>) ...
the Editors of <i>Linux Gazette</i>...
and You!
</STRONG></BIG> </TD></TR>
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</STRONG>
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<HR>
<H3>Contents:</H3>
<dl>
<dt><a href="#tag/greeting"
><strong>&para;: Greetings From Heather Stern</strong></A></dl>
<DL>
<!-- index_text begins -->
<dt><A HREF="#tag/1"
><img src="../gx/dennis/bbub.gif" height="28" width="50"
alt="(!)" border="0"
><strong>Triple booting</strong></a>
<dt><A HREF="#tag/2"
><img src="../gx/dennis/bbub.gif" height="28" width="50"
alt="(!)" border="0"
><strong>code safety</strong></a>
<dt><A HREF="#tag/3"
><img src="../gx/dennis/bbub.gif" height="28" width="50"
alt="(!)" border="0"
><strong>PC-MOS</strong></a>
<dt><A HREF="#tag/4"
><img src="../gx/dennis/qbub.gif" height="28" width="50"
alt="(?)" border="0"
><strong>restoring broken X connections</strong></a>
<!-- index_text ends -->
</DL>
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<A NAME="tag/greeting"><HR WIDTH="75%" ALIGN="center"></A>
<H3 align="left"><img src="../gx/dennis/hbubble.gif"
height="50" width="60" alt="(&para;) " border="0"
>Greetings from Heather Stern</H3>
<!-- begin hgreeting -->
<blockQuote>
Welcome once more folks, to the world of The Answer Gang. We haven't
decided where to hang the stockings; Tux goes out on Geek Cruises all
the time, so he's rarely found at the South Pole anymore. Perhaps I
should create a <TT>/hearth</TT> in my home directory, and give it a <TT>/chimney</TT>,
some <TT>/stockings</TT>, and what the heck, <TT>/menorah</TT>, <TT>/presents</TT>, and
<TT>/peace.on.earth.</TT> Top things off with a <TT>/var/log/yule</TT> we can burn in
January, and...
</blockQuote>
<blockQuote>
Oh, you didn't want to hear all this silliness. You wanted to get
to the presents. Well, I can tell you this little nerdette is still
looking for LCD monitor prices to come down. I guess my New Year's
Resolution will have to be running past a nice scanner.
</blockQuote>
<blockQuote>
If you can't think of anything for the geek in your life, I recommend
a good uninterruptible power supply (UPS). We can always use more...
</blockQuote>
<blockQuote>
For those who are wondering, the top reason for anyone not getting
answered this month is: insufficient detail! Folks, we're pretty
smart, and might even be accused of telepathy, but we are not there
in the room with you, so we can't see that machine. We really need
those error messages, any bleeps it's making, how it worked before
and what you were expecting of it. With these things, we can provide
answers you probably had no idea were available ... beyond just how
to do the thing you think will work. WIthout these hints, we're
as blind and as stumped as you are to what's going on.
</blockQuote>
<blockQuote>
To all the tiny elves, Kris Kringles and Gnomes in our computers,
enjoy your extra trons and blinkylights this season.
</blockQuote>
<!-- end hgreeting -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<A NAME="tag/1"><HR WIDTH="75%" ALIGN="center"></A>
<!-- begin 1 -->
<H3 align="left"><img src="../gx/dennis/bbubble.gif"
height="50" width="60" alt="(!) " border="0"
>Triple booting</H3>
<p><strong>From Raj Shekhar
</strong></p>
<p align="right"><strong>Comments By Mike Orr, Heather Stern, Rick Moen
</strong></p>
<blockquote><em><font color="#000066">In response to LG 84, Tips 25:
<A HREF="../issue84/lg_tips.html#25"
>http://www.linuxgazette.com/issue84/lg_tips.html#25</A>
-- Heather</font></em></blockquote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Muthukumar Kalimani wanted to install three
operating systems on his box. I had helped
my friend do the same and here are some hard
found lessons.
</STRONG></P>
<Strong><ul>
<LI>Use "fdisk" from your Linux
distro CD to create partitions. Use the
expert mode to partition the hard disk and
use cylinder numbers for specifying partition
sizes.
<LI>Using fdisk create a 25Mb - 30 Mb partition
which is below cylinder number 1024. This will
be the partition in which you will install the
/boot of Linux OS.
</ul></Strong>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Mike]
The Large Disk HOWTO
<A HREF="http://www.tldp.org/HOWTO/Large-Disk-HOWTO.html"
>http://www.tldp.org/HOWTO/Large-Disk-HOWTO.html</A>
claims this is mostly not a problem any more.
</blockQuote>
<blockQuote>
(Paranoid people like myself continue to place
<TT>/boot</TT> partitions and C: partitions below 1024.)
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Rick]
In theory, it went away in 1994.
</blockQuote>
<blockQuote>
That was the year that motherboard manufacturers rolled out Yet Another
BIOS Extension, providing a new method by which boot-time software could
get extended BIOS routine 13h information to directly address logical
cylinders numbered 1024 and above. A new version of LILO immediately
came out, that requested and could process that BIOS information.
</blockQuote>
<blockQuote>
So, in theory, the only people who need put <TT>/boot</TT> below the 1024th
logical cylinder are
</blockQuote>
<blockQuote><ol>
<LI>using really antique booting software (a very bad idea) or
<LI>contending with very old motherboard BIOSes, usually on 486es. I'm
unclear on whether any early Pentium motherboards used the older-version
int 13h call, or whether it's a 486-only issue.
</ol></blockQuote>
<blockQuote>
A lot of us old-timers retain the <TT>/boot-filesystem-first</TT> habit just from
long usage, but also because people sometimes come in the door with
antique BIOSes and fail to mention that fact. Better to put <TT>/boot</TT> near
the outer tracks than risk spending considerable effort building a
system and then find it unbootable.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Heather]
Rick and I both do installfests; I especially help people with laptops,
which have all sorts of oddball things in their BIOS. It's far easier
to obey this rule of thumb than have to do things over on the limited
time available at such install parties (usually only about 4 or 5 hours,
but people arrive late, and would rather spend time learning the diffs
between K and Gnome, set up their mailer, etc).
</blockQuote>
<blockQuote>
I think it's important to note that <TT>/boot</TT> doesn't care about being
first, only about early on the disk (if it cares at all). I usually
give it partition 2; that satisfies some MSwin setups that want the
first entry, and avoids the 4th entry, which some hibernation setups
like to take. Make the third an extend partition, put a D: in there
if you were planning a more even split on a large disk, a swap, and
at least one more volume for <TT>/</TT> (though I refer you to past articles
for The Gang's recommendations about partition layout beyond that).
</blockQuote>
<blockQuote>
If you are really trying for maximum space "under the bar" assigned
elsewhere instead ... it can be as small as 7 or 8 MB.
I wouldn't go smaller for fear that monolithic kernels might
get pretty big at some point. You always want room for three things:
the bootloader parts themselves, a known good kernel, and whichever
one you are recently trying out. If you're triple-or-more booting
and more than one are Linux, you might want to lean the other
direction and make room for lots of modules to go with them (symlink
<TT>/lib/modules</TT> to <TT>/boot/modules</TT> in all distros and share the goodies).
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
If you want to know more about Partitioning
using "fdisk" refer to:
</STRONG></P>
<blockquote><em><font color="#000033"><br>Linux Partition HOWTO
<br>by Tony Harris and Kristian Koehntopp
<br>(it is a mini HOWTO)
<br>in particular see section [5] [Partitioning with fdisk]
<br> http://www.tldp.org/HOWTO/mini/Partition/index.html
</font></em></blockquote>
<Strong><ul>
<LI>install Win98 first and give it the first
partition i.e. allow it to place itself in c:.
If you do not do this Win98 usually corrupts
whatever OS (even if it is from Win family)
is placed on C:.
</ul></Strong>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Heather]
If you create the FAT filesystem for it ahead of time,
MSwin's <TT>SETUP.EXE</TT> usually won't gratuitously fill the entire
disk for you, which saves digging up a resizer later.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
</STRONG></P>
<Strong><ul>
<LI>When you install Linux remember to place the
/boot on the partition you created for it.
<LI>If you have trouble booting into your Linux
after you have installed all three OSs, you need
a Operating System loader.
Use Google Search to find any of the following
loaders
<LI>XOSL -&gt; Nice GUI
<LI>Boot Part -&gt; Light weight and CLI (non-GUI)
</ul></Strong>
<P><STRONG>
Hope you find this relevant.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Mike]
Are you specifically excluding LILO and GRUB? Why?
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
I had written that the querent needs to
install a loader <em> _if</em> he has <em>trouble_</em>
booting into GNU/Linux (using either GRUB/LILO).
I had installed RH 7.1 with Win2k and I had
trouble booting into GNU/Linux.
RH 7.1 came with LILO version 21.4-4
</STRONG></P>
<P><STRONG>
Thankfully this problem was well documented
in Linux+NT-Loader mini-HOWTO
It had adviced to use
Boot Part for solving this problem.
I am still using Boot Part to boot into
my GNU/Linux(RH 7.1) OS.
I think newer versions of RH do not show this
problem but I am not sure as I have
only RH 7.1. (thinking of shifting to
<A HREF="http://www.debian.org/">Debian</A>).LILO does not need any special
hacking to detect and boot up Win98.
</STRONG></P>
<P><STRONG>
One of my friends had discovered XOSL
and even though he was a newbie, he had
three OSs up and running in no time.
(Win 98,WinXP,Linux and maybe Win2k too!)
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Mike]
GRUB is more user-friendly than LILO. I wish I could use it
on my computer but the "linear" option doesn't work. I had
to switch back to LILO because my computer won't work with
the "lba32" setting.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Talking about loaders, three years back
I experimented with Be OS.It was really
cool and really sparing of machine resources.
I had Win98 installed on my box. It installed
quite easily on FAT filesystem and it placed an
icon on my Win98 desktop. On clicking it, Be
would boot up. And I think it did not take much
time to startup. I removed it beacuse it did
not come bundled with much apps. What I wanted to
know do we have this sort of funky loader in
GNU/Linux?
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Heather]
Yes. The canonical way to launch Linux froma running DOS
or MSwin system is a program called <TT>LOADLIN.EXE.</TT> I understand
there is a mildly different version of it for NT, and you should
prepare a PIF for it that tells MSwin it's okay to give it all
the resources it needs - go ahead and take over the CPU - then
you'll have a happy one way trip to whatever kernel you told it
to load. Oh yeah, and the linux kernel you use has to be
visible in your DOS filesystem. I usually suggest to keep
such parts in C:\LINUX so it's obvious.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
I have not experimented with GRUB but LILO
can be tough for a newbie (IMVVHO). Again
I am talking about the older versions and
I have no experience with newer versions.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Rick]
A lot of people never learned the Zen of LILO:
</blockQuote>
<blockQuote><ol>
<LI>/sbin/lilo (the "map installer") is best thought of as a compiler,
and /etc/lilo.conf as its source code.
<LI>Therefore, if you change /etc/lilo.conf or any of the files it
points to, you must run /sbin/lilo before rebooting, to "recompile".
<LI>You should always have a "safeboot" stanza in /etc/lilo, pointing
to a known-good kernel image that you never fool with, as a
fallback. This ensures that if, e.g., you compile a new kernel but
accidentally omit console support, you can easily recover.
</ol></blockQuote>
<blockQuote>
GRUB is a capable and flexible bootloader, but practically all of the
reasons commonly cited for it being preferable to LILO boil down to
"I once messed with my boot files before reading LILO documentation,
shot myself in the foot, and therefore blame LILO."
</blockQuote>
<!-- end 1 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<A NAME="tag/2"><HR WIDTH="75%" ALIGN="center"></A>
<!-- begin 2 -->
<H3 align="left"><img src="../gx/dennis/bbubble.gif"
height="50" width="60" alt="(!) " border="0"
>code safety</H3>
<p><strong>From Jose Nazario
</strong></p>
<p align="right"><strong>Comments By Mike Orr, Ben Okopnik, Steve Kemp, Tom Bradley
</strong></p>
<P><STRONG>
i was looking through the november issue of linux gazette and something
caught my eye. overall the issue had a few things i was pretty happy to
see: a piece on mono, elf kernel execution, and adding loadable plugins to
code. it's this last piece i have a problem with.
</STRONG></P>
<P><STRONG><DL><DT>
Adding Plugin Capabilities To Your Code:
<DD><A HREF="../issue84/bradley.html"
>http://www.linuxgazette.com/issue84/bradley.html</A>
</DL></STRONG></P>
<P><STRONG>
tom bradley's code, while demonstration code, is a perfect example of
unreliable code and illustrates why this kind of thing should be avoided.
in main.c (truncated to save space):
</STRONG></P>
<pre><strong>#define PATH_LENGTH 256
...
char path[PATH_LENGTH], * msg = NULL;
...
/* build the pathname for the module */
getcwd(path, PATH_LENGTH);
strcat(path, "/");
strcat(path, argv[1]);
</strong></pre>
<P><STRONG>
it's quite trivial to overflow path[PATH_LENGTH], even inadvertantly.
before you say "look, this isn't setuid root, this isn't anything but
demonstration code, don't rush off to bugtraq" i want to say this: for
precisely the reason that it is demonstration code it should do bounds
checking.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Ben Okopnik]
Agreed, 100%. One of the many security-related sites I read on a regular
basis had a "ha-ha-only-serious" quote that's worth paying attention to:
</blockQuote>
<blockQuote><BLOCKQuote>
&lt;ironic&gt;
Security hint of the day:
</BLOCKQuote></blockQuote>
<blockquote><pre> find . -name '*.[ch]' | xargs egrep -l 'sprintf|strcat|strcpy' | xargs rm
</pre></blockquote>
<blockQuote>
&lt;/ironic&gt;
-- Pavel Kankovsky aka Peak
</blockQuote>
<blockQuote>
Funny, but...
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Steve Kemp]
There are a few decent scanning tools available, like 'flawfinder', 'rats',
and 'its' which are worth using if you want to be scared!
</blockQuote>
<blockQuote><CODE>
Steve
<BR>---
<BR># <A HREF="http://www.debian.org/">Debian</A> Security Audit Project
<BR><A HREF="http://www.steve.org.uk/Debian"
>http://www.steve.org.uk/Debian</A>
</CODE></blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
lots of people are going to code their apps with this as a start and not
think twice about the reliability of the foundation of this code. the
fact is someone can easily hit this upper limit inadvertantly (think of a
well organized person who has a deep directory structure ... suddenly
path[] has a lot less overhead).
</STRONG></P>
<P><STRONG>
secondly, bounded string manipulation should just be a habit, and habits
develop after repeated application of the effort. crappy, unchecked
runtime errors are the bane of software quality, there's no reason you
shouldn't always do sanity checks, even in demo code. one reason alone to
do it is that you'll get so annoyed you may want to improve the interface
to error checked code, benefitting us all.
</STRONG></P>
<P><STRONG>
anyhow, thanks for the november issue.
</STRONG></P>
<blockquote><em>Forwarding to the author, Tom Bradley &lt;<A HREF="mailto:tojabr@tojabr.com"
>tojabr@tojabr.com</A>&gt;. This message will
be in December's <EM>LG</EM> . Feel free to write a response or a follow-up article
if you wish.
-- Mike</em></blockquote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
thanks mike. tom, in all seriousness that article was really cool and
timely, and i will definitely be referring to it to make use of it. i just
take issue with unchecked errors in code ...
</STRONG></P>
<P><STRONG>
thanks for an otherwise well written piece.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Tom Bradley]
I agree that was setting a bad example on my part, below is a corrected
version.
</blockQuote>
<blockQuote>
(truncated to only changed partion)
...
</blockQuote>
<blockQuote>
char * path, * msg = NULL;
int (*entry)();
void * module;
</blockQuote>
<blockQuote>
if(argc &lt; 2) {
</blockQuote>
<blockQuote>
printf("No module given.\n");
return;
}
</blockQuote>
<blockQuote>
path = (char*)get_current_dir_name();
path = (char*)realloc(path, strlen(path) + strlen(argv[1]) + 2);
strcat(path, "<TT>/</TT>");
strcat(path, argv[1]);
...
</blockQuote>
<blockQuote>
the #define has been removed.
</blockQuote>
<blockQuote>
Tom
</blockQuote>
<!-- end 2 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<A NAME="tag/3"><HR WIDTH="75%" ALIGN="center"></A>
<!-- begin 3 -->
<H3 align="left"><img src="../gx/dennis/bbubble.gif"
height="50" width="60" alt="(!) " border="0"
>PC-MOS</H3>
<p><strong>From Reilly Burke
</strong></p>
<p align="right"><strong>Comments By Thomas Adams, Mike "Iron" Orr, Heather Stern
</strong></p>
<blockquote><IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Heather] Reilly Burke is Technical Advisor for a company called Aero Training
Products, Inc. (<A HREF="http://www.aerotraining.com"
>http://www.aerotraining.com</A>)
</blockquote>
<P><STRONG>
To Derek Holliday
</STRONG></P>
<P><STRONG>
We have copies of PC-MOS and LanLink available. We also produce LanLink
drivers for PC-MOS.
</STRONG></P>
<P><STRONG>
PC-MOS is required to run POS systems with DOS applications. <A HREF="http://www.dosemu.org/">DOSEMU</A> is not
good enough to run many (most) of the apps. PC-MOS is file-compatible with
DOS systems, but only the November 93 kernel (of PC-MOS) can access 3.5"
floppies.
</STRONG></P>
<P><STRONG>
I'd love to replace our PC-MOS applications, but nothing quite measures up
yet. Linux is nowhere near being able to do the job (it's way too big,
complex, &amp; geeky)! Possibly DR-DOS 8 (coming out in spring 2003 with FAT32)
might do the job.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Thomas]
How would you know until you tried? Just because Linux
is too big and "geeky" in your eyes; does not mean to
say that it couldn't do the job! It's not really
logical to say that.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Iron]
DOS <EM>programs</EM>, however, often access the hardware directly, so it's
not surprising DOSEMU can't emulate the environment quite well enough.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Heather]
Thanks for this tip on an old thread; it's not Linux, but since we
seem to be the only place that talks about it...
</blockQuote>
<blockQuote>
I'm curious about what the problems under DOSEMU + (say) MS-DOS 5.0 are,
but unless this is a problem you're trying to solve for yourself, you
may not want to bother delving any further.
</blockQuote>
<blockQuote>
The buzzword "point of sale" typed into the <A HREF="http://www.freshmeat.net/">Freshmeat</A> search index
(<A HREF="http://freshmeat.net"
>http://freshmeat.net</A>) yields 7 direct hits, and a category for
point of sale containing 42 projects. Well over a year ago I saw
one written up in a magazine article (I think it was <EM>Linux Journal</EM>
actually) about a POS system optimized for a pizza place. That's
geeky; but the pizzas he was selling are real.
</blockQuote>
<blockQuote>
Some of these projects will really be "e-business" (aimed at web based
stores, not one where a high school student has to run the register,
nor where the machine has a real register to pop the change out of)
and a few of them are optimized for a specific kind of shop. But they
may do for some people.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Of course we're still trying to move our PC-MOS apps to Linux, but so
far, after years of experimenting and coding, we're still running the
PC-MOS systems because there's still nothing like them for Point-Of-Sale
utility. It's fast and small and entirely bug-free. The last PC-MOS
kernel released was November 93 (9 years ago). But it's designed for
old hardware (ISA slots, NE2000 ethernet cards, Wyse terminals, and
serial printers), and the systems are becoming increasingly difficult
to maintain. There's probably still 100,000 PC-MOS users looking for
an answer, but the closest thing is probably DR-DOS. Linux is not being
maintained by POS geeks, so there's a real shortage of Linux POS tools
and solutions.
</STRONG></P>
<P><STRONG>
We've tried disassembling the drivers (we succeeded in cloning the Lan
client drivers with new serial numbers!) , but disassembling the entire
OS is far too complicated. We've also tried rewriting the DOS apps (in
particular, the Shark database). We have its horribly complicated
monolithic Microsoft C source code, with chunks of assembler mixed in,
but it's still a giant task. The only feasible direction looks like
rewriting the Shark compiler in Kylix, but even that is a horrendous
prospect. So far, PC-MOS still works (and it's paid for
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)"
height="24" width="20" align="middle">, and the
Shark database is still fast and flexible.
</STRONG></P>
<P><STRONG>
We'd really like to hear from any other POS types who are trying to move
to Linux.
</STRONG></P>
<P><STRONG>
Reilly Burke
</STRONG></P>
<!-- end 3 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<A NAME="tag/4"><HR WIDTH="75%" ALIGN="center"></A>
<!-- begin 4 -->
<H3 align="left"><img src="../gx/dennis/qbubble.gif"
height="50" width="60" alt="(?) " border="0"
>restoring broken X connections</H3>
<p><strong>From Mustafa C. Kuscu
</strong></p>
<p align="right"><strong>Answered By Jay R. Ashworth, Rick Moen, Robos, Heather Stern, Kapil Hari Paranjape
</strong></p>
<P><STRONG>
Hi, James. When a remote X-forwarding ssh connection is broken, all the
windows at my local server get lost. Is there a way to prevent the remote
processes from shutting down, so as to resume the processes and have the
windows re-sent to the local X-server when I relogin?
</STRONG></P>
<P><STRONG>
Thanks
Mustafa
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [jra]
Not per se, but investigate VNC. I'm in the midst of writing an
article on it as it happens, but it can be used to do what you need.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Rick]
Jay, just to help: I know of these VNC implementations (also known as
"RFB" = Remote Frame Buffer):
</blockQuote>
<blockQuote><ul>
<LI>RealVNC, formerly AT&amp;T Cambridge's reference implementation,
<A HREF="http://www.realvnc.com"
>http://www.realvnc.com</A>
<LI>TridiaVNC, <A HREF="http://www.tridiavnc.com"
>http://www.tridiavnc.com</A>
<LI>TightVNC, <A HREF="http://www.tightvnc.com"
>http://www.tightvnc.com</A>
<LI>x0rfbserver (great name, eh?), <A HREF="http://www.hexonet.de/software/x0rfbserver"
>http://www.hexonet.de/software/x0rfbserver</A>,
optionally with kfrb, <A HREF="http://www.tjansen.de/krfb"
>http://www.tjansen.de/krfb</A> or x0rfb from the
rfb package, <A HREF="http://hexonet.de/software/rfb"
>http://hexonet.de/software/rfb</A>
</ul></blockQuote>
<blockQuote>
You'll find a number of resources about VNC over SSH in my ssh-clients
file, <A HREF="http://linuxmafia.com/pub/linux/security/ssh-clients"
>http://linuxmafia.com/pub/linux/security/ssh-clients</A>
</blockQuote>
<blockQuote>
Also worth looking into:
</blockQuote>
<blockQuote><ul>
<LI>MLView DXPC, <A HREF="http://www.medialogic.it/projects/mlview"
>http://www.medialogic.it/projects/mlview</A> : Compressed
and proxied X11 -- sort of an update of the LBX idea. Much faster
than VNC.
<LI>rdesktop, <A HREF="http://www.rdesktop.org"
>http://www.rdesktop.org</A>, an RDP client for Windows
Terminal Services. Likewise much faster than VNC; also, fully
multiuser, unlike VNC.
</ul></blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Robos]
Well, not entirely true IIRC since I had some thoughts about this lately too
and shortly after that a friend of mine told me that there exists something
like screen for xserver connections. And now guess what, he and me forgot
it again. Great. So, it exists, but somewhere and I can't tell where...
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Rick]
Possibly, you're trying to think of xnest?
</blockQuote>
<blockquote><IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Heather] I suspect not; xnest handles issues about color depth, not being able
to set processes to sleep and waken them up from another console.
</blockquote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Kapil]
Actually you may mean "ratpoison" but that is only a window manager
which has a "screen"-ish look and feel.
</blockQuote>
<blockQuote>
The following setup works well for me from home and work.
</blockQuote>
<blockQuote>
At work:
</blockQuote>
<blockquote><em><font color="#000033"><br>start ratpoison
<br>get ratpoison to start rfb (or to give its full name x0rfbserver).
<br>get ratpoison to start a screen session.
</font></em></blockquote>
<blockQuote>
Do some real work via screen.
</blockQuote>
<blockQuote>
(All programs that invoke graphics work via ratpoison).
</blockQuote>
<blockQuote>
At Home:
</blockQuote>
<blockquote><em><font color="#000033"><br>run ssh -L 5900:localhost:5900 to the work machine.
<br>on the remote machine run "screen -D -R"
<br>start xvncviewer on the local machine.
</font></em></blockquote>
<blockQuote>
Do some real work via screen!
</blockQuote>
<blockQuote>
Thus text based applications work via ssh and screen so are
reasonably fast. Meanwhile any remote program that invokes graphics
creates a window within the xvncviewer.
</blockQuote>
<blockQuote>
Needless to say ratpoison runs at home too!
</blockQuote>
<blockQuote>
I was quite pleased when I cooked up this config as you can see!
</blockQuote>
<blockQuote>
As long as the machine at work continues to run none of the sessions
is ever exited or lost. VNC and screen passwrods provide some security
as well.
</blockQuote>
<blockQuote>
Hope this helps,
</blockQuote>
<blockQuote>
Kapil.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Robos]
Nope, I found it! I actually mean - xmove! Look here:
</blockQuote>
<blockQuote><BLOCKQuote>
<A HREF="ftp://ftp.cs.columbia.edu/pub/xmove"
>ftp://ftp.cs.columbia.edu/pub/xmove</A>
</BLOCKQuote></blockQuote>
<blockQuote>
Thats also the thing the original querent might wanna have.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Kapil]
I tried out "xmove". Er, ... just one problem. It uses TCP connections
to connect with the xserver which means that X with "-nolisten tcp"
does not work.
</blockQuote>
<blockQuote>
In the modern security conscious world this is essentially all X
servers!
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Robos]
Well, thats true. But, you can either remove the call in
<TT>/etc/X11/xinit/xserverrc</TT> and maybe <TT>/etc/gdm/gdm.conf</TT> (dunno for kdm or xdm)
or ssh -X <em> _should</em> be permitted if I gather some comment I read correctly.
The say the others?
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Heather]
As far as X is concerned ssh -X merely yields a valid server running at
a higher screen number - 10 rather than 1 is typical, so localhost:10
would send all processes down the ssh pipe back to where you are
sitting.
</blockQuote>
<blockQuote>
If you're sure it works at the TCP level it may not work. If it works
with normal TCP/IP packets, then it can surely be tunneled. But you can
try playing games with ssh at the transport layer first. There are
stacks of examples for POP over SSH out there; that's how they work,
so it's worth a look too.
</blockQuote>
<!-- end 4 -->
<P> <hr> </p>
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<h5>
<br>Copyright &copy; 2002
<br>Copying license <A HREF="">http://www.linuxgazette.com/copying.html</A>
<BR>Published in Issue 85 of <i>Linux Gazette</i>, December 2002</H5>
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<TABLE BORDER><TR><TD WIDTH="200">
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</TD><TD WIDTH="380">
<CENTER>
<BIG><BIG><STRONG><FONT COLOR="maroon">News Bytes</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/conry.html">Michael Conry</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
</p><center>
<table cellpadding="7"><tbody><tr><td>
<img src="../gx/bytes.gif" border="1" alt="News Bytes">
</td><td>
<h3>Contents:</h3>
<ul>
<li><a href="#leg">Legislation and More Legislation</a>
</li><li><a href="#links">Linux Links</a>
</li><li><a href="#conferences">Conferences and Events</a>
</li><li><a href="#general">News in General</a>
</li><li><a href="#distro">Distro News</a>
</li><li><a href="#commercial">Software and Product News</a>
</li></ul>
</td></tr></tbody></table>
<strong>Selected and formatted by <a href="mailto:michael.conry@softhome.net">Michael Conry</a></strong>
</center>
<p> Submitters, send your News Bytes items in
<font size="+2"><strong>PLAIN TEXT</strong></font>
format. Other formats may be rejected without reading. You have been
warned! A one- or two-paragraph summary plus URL gets you a better
announcement than an entire press release. Submit items to
<a href="mailto:gazette@ssc.com">gazette@ssc.com</a>
</p><hr> <p>
<!-- =================================================================== -->
</p><h3><img alt=" " src="../gx/bolt.gif">
<font color="green">
December 2002 <i>Linux Journal</i>
</font>
</h3>
<img alt="[issue 102 cover image]" src="misc/bytes/lj-cover104.png" width="200" height="268" align="left" hspace="20">
The December issue of <a href="http://www.linuxjournal.com/"><i>Linux
Journal</i></a> is on newsstands now.
This issue focuses on System Administration. Click
<a href="http://www.linuxjournal.com/modules.php?op=modload&amp;name=NS-lj-issues/issue104&amp;file=index">here</a>
to view the table of contents, or
<a href="http://www.linuxjournal.com/subscribe/">here</a>
to subscribe.
<p>
<font color="green">All articles older than three months are available for
public reading at
<a href="http://www.linuxjournal.com/magazine.php">http://www.linuxjournal.com/magazine.php</a></font>.
Recent articles are available on-line for subscribers only at
<a href="http://interactive.linuxjournal.com/">http://interactive.linuxjournal.com/</a>.
<!--
<P> <STRONG>Just for fun:</STRONG> a cover image that was axed from publication
is on the <A HREF="lg_backpage.html">Back Page</A>.
-->
<BR CLEAR="all">
<!-- =================================================================== -->
<a name="leg"></a>
<p><hr><p>
<!-- =================================================================== -->
<center><H3><font color="green">Legislation and More Legislation</font></H3></center>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">DMCA
</FONT>
</H3>
<P>
Finding bizarre implications of the DMCA with which to ridicule it is as
easy as shooting fish in a barrel. The Register recently reported that
four major retailers (WalMart, Target, Best Buy and Staples) had
<a href="http://www.theregister.co.uk/content/6/28223.html">
invoked the DMCA</a> to prevent
<a href="http://www.fatwallet.com">FatWallet.com</a> from disseminating
information about sales and price comparisons. The argument runs that sale
prices are copyrightable information (and not just simple facts).
FatWallet has had to
<a href="http://www.fatwallet.com/forums/messageview.cfm?start=0&catid=18&threadid=126042">
comply</a> to avoid the risk of a very costly legal battle.
<P>
In other DMCA related matters, Security Focus reported that hardware
manufacturers producing games console mod chips
<a href="http://online.securityfocus.com/columnists/119">
have found themselves under pressure</a>, applied through the device of the
DMCA, to cease such production. The argument hinges on whether the
non-infringing uses legitimise the chips, and its a criterion which can
vary substantially from country to country.
<P>
Finally, there is a very interesting
<a href="http://www.tidbits.com/tb-issues/TidBITS-656.html#lnk3">
DMCA article</a>
by Adam C. Engst at
<a href="http://www.tidbits.com/">TidBITS</a>. It provides a good overview
of the issues arising from the law, and the stakes the "content industry"
is playing for in its long-term strategy.
Related to this is
another article at TidBITS (by Cory
Doctorow) entitled
<a href="http://www.tidbits.com/tb-issues/TidBITS-642.html#lnk2">
Can the Digital Hub Survive Hollywood?</a>. It does a fine job of
highlighting the tensions between the content/media industries versus the
interests of the technology industry at large (as opposed to the welfare
of sectoral interests within the tech industry who might do very well if
their technology is used for protecting "content"). Particular attention
is paid to the BPDG (Broadcast Protection Discussion Group).
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">Mobilix
</FONT>
</H3>
<P>
In a reversal of an lower court's decision, a
<a href="http://newsvac.newsforge.com/newsvac/02/11/23/1424224.shtml?tid=17">
German court has ruled</a>
that the name Mobilix is sufficiently close in sound and appearance to
Obelix to cause confusion. Mobilix is a website dealing with the area of
Unix on mobile devices. Obelix is a character from a French comic book.
The final implications of this decision are not clear. You can follow the
entire story
<a href="http://mobilix.org/mobilix_asterix.html">
on the Mobilix website</a>.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">DRM
</FONT>
</H3>
<P>
Slashdot recently
<a href="http://developers.slashdot.org/article.pl?sid=02/11/19/2054212&mode=nested&tid=156">
reported</a> on the
<a href="http://crypto.stanford.edu/DRM2002/prog.html">
ACM Digital Rights Management Workshop</a>. Among those present was Ed
Felten whose
<a href="http://www.freedom-to-tinker.com/archives/000199.html">
brief commentary can be read here</a>. It was reported that there was some
scepticism that DRM was truly a panacea for the copy-protection worries of
Hollywood info-hoarders.
In a not unrelated story, The Register
<a href="http://www.theregister.co.uk/content/4/28016.html">
reported on the future of Microsoft's Palladium</a> and the Trusted
Computing Platform Alliance (TCPA). Even proponents of the system admit it
is not totally secure and potentially vulnerable to intelligent hardware
attacks.
<a name="links"></a>
<p><hr><p>
<!-- =================================================================== -->
<center><H3><font color="green">Linux Links</font></H3></center>
<P>
Some links from <a href="http://lwn.net/">Linux Weekly News</a>:
<ul>
<li>
<a href="http://lwn.net/Articles/14115/">
Summary of a US Department of Defence report</a> on its level of use of
free software. The initial brief for the report was to evaluate the
possibility of banning such software, but the final document is quite
positive on the role and importance of free software to the
department's operations.
</li>
<li>
<a href="http://cin.earthweb.com/article/1,3555,10493_1497311,00.html">
Linux in emergency-response switchboards</a>.
</li>
<li>
<a href="http://lwn.net/Articles/16345/">
LinDVD, a Linux DVD player</a>. Available only to OEMs for embedded
systems, not to individuals.
</li>
</ul>
<P>
<P>
Some links from the O'Reilly websites:
<ul>
<li>
<a href="http://linux.oreillynet.com/pub/a/onlamp/2002/11/07/linux_threads.html">
An article on the future of threads in Linux</a>.
</li>
<li>
<a href="http://www.onlamp.com/pub/a/python/2002/10/17/biopython.html">
Python for Bioinformatics</a>.
</li>
<li>
<a href="http://www.onlamp.com/pub/a/bsd/2002/11/14/FreeBSD_Basics.html">
The SSH Cryptosystem</a>.
</li>
<li>
<a href="http://www.onlamp.com/pub/a/onlamp/2002/11/14/trisentry.html">
TriSentry, a Unix Intrusion Detection System</a>.
</li>
</ul>
<P>
DesktopLinux.com have
<a href="http://www.desktoplinux.com/articles/AT7096363910.html">
an article</a> about
<a href="http://filmgimp.sourceforge.net/">
Film Gimp</a>. Film Gimp is a motion picture frame-editing tool. The
article has some technical details and reports on its use in the film
industry.
<P>
<em>Linux Journal</em> have
<a href="http://www.linuxjournal.com/article.php?sid=6439">
an article</a>
explaining how to train mutt to catch spam using ESR's bogofilter.
<P>
News.com have
<a href="http://news.com.com/2100-1001-966312.html?tag=fd_top">
reported</a>
on IBM's plans to build two new machines which would be the fastest
supercomputers to date. The Blue Gene/L, the faster of the
two, will be Linux powered, and 10 times faster than the current
title-holder, NEC's Earth Simulator.
<P>
A
<a href="http://debianlinux.net/multimedia.html">
survey of some open source multimedia projects</a> which might be of
interest.
<p>
Some links from
<a href="http://www.linuxtoday.com/">Linux Today</a>
<ul>
<li>
Linux and Main article on
<a href="http://www.linuxandmain.com/modules.php?name=News&file=article&sid=278">
The Linux kernel as a periodical publication</a>, and Linus as editor
in chief.
</li>
<li>
NewsForge
<a href="http://newsforge.com/newsforge/02/10/25/1728232.shtml?tid=2">
talk to Jay Beale</a> of Bastille on improving Linux security
</li>
<li>
<a href="http://www.osdir.com/modules.php?op=modload&name=News&file=article&sid=76&mode=thread&order=0&thold=0">
OSDir.com interview</a> with Bram Moolenaar (most famous for
<a href="http://www.vim.org/">VIM</a>) on the subject of his new project,
<a href="http://www.a-a-p.org/">A-A-P</a>. A-A-P aims to be a kind of
"super make".
</li>
</ul>
<P>
<a href="http://www.theinquirer.net/">
The Inquirer</a> has run a series of articles describing the Linux install
process in a way designed to help beginners. Parts
<a href="http://www.theinquirer.net/?article=6080">
1</a>,
<a href="http://www.theinquirer.net/?article=6102">
2</a>,
<a href="http://www.theinquirer.net/?article=6122">
3</a>,
<a href="http://www.theinquirer.net/?article=6161">
4</a>,
<a href="http://www.theinquirer.net/?article=6276">
5</a>.
<P>
IBM Developerworks have
<a href="http://www-106.ibm.com/developerworks/linux/library/l-oslab/?t=gr,lnxw02=OSlab">
an article on open source scientific software</a>, being used increasingly
by those involved in scientific research.
<P>
<a href="http://www.linuxandmain.com/modules.php?name=News&file=article&sid=271">
A report</a> at Linux and Main on the path to the next major kernel
release.
<P>
<a href="http://www.debian.org/News/weekly/2002/46/">
From Debian Weekly News</a>, a link to
<a href="http://www.distrowatch.com/interview-knoppix.php">
an interview</a> with Klaus Knopper of
<a href="http://www.knoppix.org/">Knoppix</a>. Particular comments on
hardware detection implementation.
<P>
Some links of interest from <a href="http://www.theregister.co.uk/">The
Register</a>:
<ul>
<li>
IBM's S/390 Linux guru interviewed on the
<a href="http://www.theregister.co.uk/content/4/28183.html">
Open Source patent question</a>
</li>
<li>
<a href="http://www.theregister.co.uk/content/4/27998.html">
A guide for relatively experienced users</a> on securing your data
under Linux.
</li>
<li>
Brussels to spend &euro;250k on
<a href="http://www.theregister.co.uk/content/4/27853.html">
Linux migration study</a>
</li>
<li>
<a href="http://www.theregister.co.uk/content/4/27878.html">
Namibia rejects MS in favour of Linux</a>
</li>
</ul>
<P>
Some links from
<a href="http://slashdot.org/">Slashdot</a> which may interest you:
<ul>
<li>
<a href="http://slashdot.org/articles/02/11/05/0227236.shtml?tid=95">
Community wireless network</a>
in Bristol, England.
</li>
<li>
Humorix reports that Red Hat is hoping to
<a href="http://i-want-a-website.com/about-linux/articles/sep02/nullify.shtml">
make a universal shell and a mutant vi/emacs hybrid editor</a>
to complement their synergised KDE and Gnome (tongue firmly in cheek).
<li>
ESR presents a recently leaked Halloween document from Microsoft
<a href="http://opensource.org/halloween/halloween7.php">
describing their strategy to combat Linux</a>. This is the latest in a
<a href="http://opensource.org/halloween/">
tradition of such leaks</a>.
</li>
<li>
<a href="http://www.infoworld.com/articles/hn/xml/02/11/13/021113hnstepup.xml?s=IDGNS">
Tablet PCs with Lindows, notebooks for $800</a>.
</li>
<li>
LinuxBIOS,
<a href="http://www.clustermatic.org/pipermail/linuxbios/2002-November/001186.html">
is a non-proprietary system BIOS</a>
that can boot Linux, Windows 2000 and OpenBSD. It works only with
certain motherboards.
</li>
<LI>
<A HREF="http://slashdot.org/articles/02/11/27/0541251.shtml?tid=154">
Mozilla 1.2</A> is out
</LI>
<LI>
Linus <A HREF="http://www.eweek.com/article2/0,3959,723328,00.as">tells</A>
eWeek about the upcoming Linux 2.6
</LI>
</ul>
<p><hr><p>
<!-- =================================================================== -->
<A NAME="conferences"></A>
<center><H3><font color="green">Upcoming conferences and events</font></H3></center>
<P> Listings courtesy <EM>Linux Journal</EM>. See <EM>LJ</EM>'s
<A HREF="http://www.linuxjournal.com/events.php">Events</A> page for the
latest goings-on.
<!-- *** BEGIN events table [this line needed by Linux Gazette events.py *** -->
<table cellpadding=5 border=0 width=100%>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>Linux-Bangalore/2002
</b><BR>
<td valign=top>December 3-5, 2002<BR>Bangalore, Inda<BR>
<a href="http://linux-bangalore.org/2002/" target="_blank">
http://linux-bangalore.org/2002/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>USENIX 5th Symposium on Operating Systems Design
and Implementation (OSDI)</b><BR>
<td valign=top>December 9-11, 2002<BR>Boston, MA<BR>
<a href="http://www.usenix.org" target="_blank">
http://www.usenix.org/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>Consumer Electronics Show</b><BR>
<td valign=top>January 9-12, 2003<BR>Las Vegas, NV<BR>
<a href="http://www.cesweb.org/" target="_blank">
http://www.cesweb.org/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>LinuxWorld Conference & Expo</b><BR>
<td valign=top>January 21-24, 2003<BR>New York, NY<BR>
<a href="http://www.linuxworldexpo.com/" target="_blank">
http://www.linuxworldexpo.com/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>O'Reilly Bioinformatics Technology Conference</b><BR>
<td valign=top>February 3-6, 2003<BR>San Diego, CA<BR>
<a href="http://conferences.oreilly.com/" target="_blank">
http://conferences.oreilly.com/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>Game Developers Conference</b><BR>
<td valign=top>March 4-8, 2003<BR>San Jose, CA<BR>
<a href="http://www.gdconf.com/" target="_blank">
http://www.gdconf.com/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>SXSW</b><BR>
<td valign=top>March 7-11, 2003<BR>Austin, TX<BR>
<a href="http://www.sxsw.com/interactive" target="_blank">
http://www.sxsw.com/interactive</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>COMDEX Canada</b><BR>
<td valign=top>March 11-13, 2003<BR>Vancouver, BC<BR>
<a href="http://www.comdex.com/vancouver/" target="_blank">
http://www.comdex.com/vancouver/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>CeBIT</b><BR>
<td valign=top>March 12-19, 2003<BR>Hannover, Germany<BR>
<a href="http://www.cebit.de/" target="_blank">
http://www.cebit.de/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>4th USENIX Symposium on Internet Technologies and Systems</b><BR>
<td valign=top>March 26-28, 2003<BR>Seattle, WA<BR>
<a href="http://www.usenix.org/events/" target="_blank">
http://www.usenix.org/events/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>4th USENIX Symposium on Internet Technologies and Systems</b><BR>
<td valign=top>March 26-28, 2003<BR>Seattle, WA<BR>
<a href="http://www.usenix.org/events/" target="_blank">
http://www.usenix.org/events/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>PyCon</b> (the first "low budget" Python conference)<BR>
<BLOCKQUOTE>
<EM>Note:</EM> This is the first <STRONG>low budget</STRONG> Python
conference, so if you've been avoiding Python conferences due to the cost, this
one is for you! Another conference, the main International Python Conference,
will be held in July as part of O'Reilly's OSCON (Open Source Convention).
</BLOCKQUOTE>
<td valign=top>March 26-28, 2003<BR>Washington, DC<BR>
<a href="http://www.python.org/pycon/" target="_blank">
http://www.python.org/pycon/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>AIIM</b><BR>
<td valign=top>April 7-9, 2003<BR>New York, NY<BR>
<a href="http://www.advanstar.com/" target="_blank">
http://www.advanstar.com/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>SD West</b><BR>
<td valign=top>April 8-10, 2003<BR>Santa Clara, CA<BR>
<a href="http://www.sdexpo.com/" target="_blank">
http://www.sdexpo.com/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>COMDEX Chicago</b><BR>
<td valign=top>April 15-17, 2003<BR>Chicago, IL<BR>
<a href="http://www.comdex.com/chicago/" target="_blank">
http://www.comdex.com/chicago/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>Real World Linux Conference and Expo</b><BR>
<td valign=top>April 29-30, 2003<BR>Toronto, Ontario<BR>
<a href="http://www.realworldlinux.com/" target="_blank">
http://www.realworldlinux.com</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>USENIX First International Conference on Mobile Systems,
Applications, and Services (MobiSys)</b><BR>
<td valign=top>May 5-8, 2003<BR>San Francisco, CA<BR>
<a href="http://www.usenix.org/events/" target="_blank">
http://www.usenix.org/events/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>USENIX Annual Technical Conference</b><BR>
<td valign=top>June 9-14, 2003<BR>San Antonio, TX<BR>
<a href="http://www.usenix.org/events/" target="_blank">
http://www.usenix.org/events/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>CeBIT America</b><BR>
<td valign=top>June 18-20, 2003<BR>New York, NY<BR>
<a href=http://www.cebit-america.com/"" target="_blank">
http://www.cebit-america.com/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>O'Reilly Open Source Convention</b><BR>
<td valign=top>July 7-11, 2003<BR>Location: TBD<BR>
<a href="http://conferences.oreilly.com/" target="_blank">
http://conferences.oreilly.com/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>12th USENIX Security Symposium</b><BR>
<td valign=top>August 4-8, 2003<BR>Washington, DC<BR>
<a href="http://www.usenix.org/events/" target="_blank">
http://www.usenix.org/events/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>LinuxWorld Conference & Expo</b><BR>
<td valign=top>August 5-7, 2003<BR>San Francisco, CA<BR>
<a href="http://www.linuxworldexpo.com" target="_blank">
http://www.linuxworldexpo.com</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
</table>
<!-- *** END events table [this line needed by Linux Gazette events.py *** -->
<a name="general"></a>
<p><hr><p>
<!-- =================================================================== -->
<center><H3><font color="green">News in General</font></H3></center>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">MySQL, NuSphere and the GPL
</FONT>
</H3>
<P>
MySQL AB has
<a href="http://www.businesswire.com/cgi-bin/f_headline.cgi?bw.110702/223110437">
settled its dispute</a>
with NuSphere corporation. MySQL AB
had claimed that NuSphere violated the GPL and misused the MySQL trademark.
(NuSphere includes MySQL with NuSphere's enhancements in its product.)
NuSphere has assigned to MySQL AB the copyrights for its contributions to
MySQL. Not so coincidentally, MySQL AB has just
<a href="http://lwn.net/Articles/15342/">
donated $25,000 to the Free Software Foundation's GPL Compliance Lab</a>,
which helps companies offering GPL'd software follow up on GPL violations.
According to the FSF's Executive Directory Bradley Kuhn, almost all GPL
violations are mistakes rather than wilful infringement.
<a name="distro"></a>
<p><hr><p>
<!-- =================================================================== -->
<center><H3><font color="green">Distro News</font></H3></center>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">Debian
</FONT>
</H3>
<P>
Debian Weekly News
<a href="http://www.debian.org/News/weekly/2002/43/">
highlighted</a> a LinuxOrbit
<a href="http://www.linuxorbit.com/modules.php?op=modload&name=Sections&file=index&req=viewarticle&artid=541">
HOWTO on installing and configuring ALSA</a>. The piece describes the
correct "Debian way" to perform the task.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">Knoppix
</FONT>
</H3>
<P>
<a href="http://www.debian.org/News/weekly/2002/45/">
Debian Weekly News Reported</a> that people from the
<a href="http://www.debian.org/devel/debian-med/">
Debian-Med subproject</a> have
<a href="http://lists.debian.org/debian-med-0211/msg00012.html">
started</a>
a Knoppix-Med project. The aim is
to include particular pieces of medical software into the Debian Based
<a href="http://www.knopper.net/knoppix/index-en.html">
Knoppix distribution</a>.
Details of the procedure
<a href="http://savannah.gnu.org/cgi-bin/viewcvs/*checkout*/gnumed/gnumed/gnumed/test-area/knoppix/readme.html">
are available online</a>.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">SuSE
</FONT>
</H3>
<P>
<a href="http://www.suse.de/en/">
SuSE Linux</a>
has announced a multi-stage product campaign for the corporate desktop
deployment of SuSE Linux. Starting January 2003, small and medium-scale
enterprises will be able to migrate to Linux on desktops using the "SuSE
Linux Office Desktop". "SuSE Linux Enterprise Desktop", a Linux version
optimised for desktop deployment in large-scale enterprises, is expected to
be released in the first quarter of 2003.
<P>
<hr width="20%" noshade>
<P>
SuSE Linux has also announced that the
<a href="http://www.suse.de/en/business/products/sles/index.html">
SuSE Linux Enterprise Server (SLES)</a>
has proved itself as a powerful Linux platform for IBM`s DB2 Version 8
database software with SLES latest certification for DB2.
SuSE Linux Enterprise Server is the first distribution to be
validated on all hardware platforms supported by DB2 for Linux
(including IBM zSeries mainframes) and validated to run DB2
Enterprise Server Edition.
More information on IBM's DB2 for Linux Validation Program
<a href="http://www.ibm.com/software/data/db2/linux/validate/">
is available online</a>.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">UnitedLinux
</FONT>
</H3>
<P>
<a href="http://www.unitedlinux.com">
The UnitedLinux group</a>
have announced the release of Version 1.0 of its UnitedLinux product, a
standards-based Linux operating system targeted at the business user.
UnitedLinux is the result of an industry initiative to streamline Linux
development and certification around a global, uniform distribution of
Linux. Founding companies of UnitedLinux are Linux industry leaders
Conectiva S.A., The SCO Group, SuSE Linux AG, and Turbolinux, Inc.
<a name="commercial"></a>
<p><hr><p>
<!-- =================================================================== -->
<center><H3><font color="green">Software and Product News</font></H3></center>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">New kernels
</FONT>
</H3>
<P>
A new stable kernel 2.4.20 has been released. A new ancient kernel 2.2.23
has also been released if you're still living in the medieval ages.
Get your update at a
<A HREF="http://www.kernel.org/mirrors/">kernel mirror</A> near you.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">Mathematica Ported to NEC's Itanium Linux Platform
</FONT>
</H3>
<P>
<a href="http://www.wolfram.com">
Wolfram Research</a>
and
<a href="http://www.nec.com">
NEC</a>
have collaborated to port
<a href="http://www.wolfram.com/products/mathematica">
Mathematica</a>
to NEC's Itanium Linux platform for the upcoming release of Mathematica 4.2.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">Appligent Alliance Program
</FONT>
</H3>
<P>
<a href="http://www.appligent.com">
Appligent</a> has unveiled a
new Alliance Program designed to help integrators and consultants
develop more powerful electronic document management applications for
their clients. Appligent's main product is a range of PDF-related software
which supports, among other operating systems, Red Hat Linux.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">Updated Opera 6.1 for Linux on Intel and PowerPC
</FONT>
</H3>
<P>
<a href="http://www.opera.com">
Opera Software</a>
have released Opera 6.1 for
Linux for Intel and PowerPC users. The PowerPC version is the first released on
this platform since the tentative Opera 5 for Linux Beta in May 2001.
In addition to several bugfixes, this release features better support
for fonts in the new version, with
font anti-aliasing enabled by default and improved support for
Chinese, Japanese and Korean characters.
<a href="http://www.opera.com/docs/changelogs/">
The changelog</a> documents all the new developments in this release.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">Pygame
</FONT>
</H3>
<a href="http://www.pygame.org/">
<img align="right" src="http://www.pygame.org/docs/pygame_tiny.gif">
</a>
<a href="http://www.pygame.org/">
Pygame</a>
is a cross-platfrom library designed to make it easy to write
multimedia software, such as games, in Python. Pygame requires the Python
language and SDL multimedia library.
A major advantage is portability, games based on Pygame can run on Windows,
NT4, MacOS, OSX, BeOS, FreeBSD and IRIX, as well as Linux.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">Cylant Secure
</FONT>
</H3>
<P>
<a href="http://www.cylant.com">
Cylant</a>
has ported the management console for its
Linux Intrusion Prevention system to Windows. The Windows console allows administrators
to managed CylantSecure server agents from their Windows workstations.
<!-- =================================================================== -->
<!-- =================================================================== -->
<!-- *** BEGIN bio *** -->
<!-- *** END bio *** -->
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2002, Michael Conry.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 85 of <i>Linux Gazette</i>, December 2002
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
<HR>
<TABLE BORDER><TR><TD WIDTH="200">
<A HREF="http://www.linuxgazette.com/">
<IMG ALT="LINUX GAZETTE" SRC="../gx/2002/lglogo_200x41.png"
WIDTH="200" HEIGHT="41" border="0"></A>
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD WIDTH="380">
<CENTER>
<BIG><BIG><STRONG><FONT COLOR="maroon">HelpDex</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/collinge.html">Shane Collinge</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<EM>These cartoons are scaled down to minimize horizontal scrolling.
To see a panel in all its clarity, click on it.</EM>
<P>
<A HREF="misc/collinge/whatpart.jpg">
<IMG ALT="[cartoon]" SRC="misc/collinge/whatpart.jpg"
WIDTH="640" HEIGHT="240"></A>
<BR CLEAR="all">
<A HREF="misc/collinge/promoting.jpg">
<IMG ALT="[cartoon]" SRC="misc/collinge/promoting.jpg"
WIDTH="640" HEIGHT="240"></A>
<BR CLEAR="all">
<A HREF="misc/collinge/millbillionaire.jpg">
<IMG ALT="[cartoon]" SRC="misc/collinge/millbillionaire.jpg"
WIDTH="640" HEIGHT="240"></A>
<BR CLEAR="all">
<A HREF="misc/collinge/kings.jpg">
<IMG ALT="[cartoon]" SRC="misc/collinge/kings.jpg"
WIDTH="640" HEIGHT="240"></A>
<BR CLEAR="all">
<P> More adventures of VI-Agra, the vi paperclip assistant, are in the
<A HREF="qubism.html">Qubism</A> column this issue, and in the back
issues under both HelpDex and Qubism.
<P> Recent HelpDex cartoons are at Shane's new web site,
<A HREF="http://www.shanecollinge.com/">www.shanecollinge.com</A>, on
the <A HREF="http://www.shanecollinge.com/Linux/">Linux</A> page.
Cartoons during his Asia trip this year are at the
<A HREF="http://www.core.org.au/modules.php?name=Cartoons">CORE</A>
CORE web site.
<P>
What's this? Shane found it in the <a
href="http://www.losamigoshostel.com/">Los Amigos</a>
hostel in Madrid. I kid you not, it's <a
href="http://dictionary.reference.com/search?q=true">true</a>.
<P>
<IMG ALT="[Picture of a fire extinguisher with the brand 'UNIX']"
SRC="misc/collinge/UnixFireExtinguisher.jpg"
WIDTH="437" HEIGHT="717">
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2002, Shane Collinge.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 85 of <i>Linux Gazette</i>, December 2002
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
<HR>
<TABLE BORDER><TR><TD WIDTH="200">
<A HREF="http://www.linuxgazette.com/">
<IMG ALT="LINUX GAZETTE" SRC="../gx/2002/lglogo_200x41.png"
WIDTH="200" HEIGHT="41" border="0"></A>
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD WIDTH="380">
<CENTER>
<BIG><BIG><STRONG><FONT COLOR="maroon">Ecol</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/malonda.html">Javier Malonda</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
These cartoons were made for es.comp.os.linux (ECOL), the Spanish USENET
newsgroup for Linux. The strips are drawn in Spanish and then translated to
English by the author. Text commentary on this page is by LG Editor Iron.
Your browser has shrunk the images to conform to the horizontal size limit for
LG articles. For better picture quality, click on each cartoon to see it full
size.
<P>
<A HREF="misc/ecol/ecol-87-e.png"><IMG SRC="misc/ecol/ecol-87-e.png" WIDTH="600" HEIGHT="240"></A>
<P>
<A HREF="misc/ecol/ecol-87.png"><IMG SRC="misc/ecol/ecol-87.png" WIDTH="600" HEIGHT="240"></A>
<P> One creative translation here. "Ecol brand" is really whiskey and Fanta.
The Spanish phrase "con naranjita" means "with a little orange", but in
practice it means "mixed with Fanta". Fanta is a carbonated orange drink. "A
favorite in Europe since the 1940s, Fanta was acquired by the Coca-Cola Company
in 1960," says the Coca-Cola web site. (I would link to it but it's a
brower-crashing site.) Whiskey and Fanta is popular in Spain, so I'm told.
Since neither the words nor the concept translate to English very well, the
author changed it to "Ecol brand", haha.
<HR NOSHADE> <!-- ****************************************************** -->
<P>
<A HREF="misc/ecol/ecol-86-e.png"><IMG SRC="misc/ecol/ecol-86-e.png" WIDTH="600" HEIGHT="270"></A>
<P>
<A HREF="misc/ecol/ecol-86.png"><IMG SRC="misc/ecol/ecol-86.png" WIDTH="600" HEIGHT="240"></A>
<P>
<HR NOSHADE> <!-- ****************************************************** -->
<A HREF="misc/ecol/ecol-62-e.png"><IMG SRC="misc/ecol/ecol-62-e.png" WIDTH="600" HEIGHT="240"></A>
<P>
<A HREF="misc/ecol/ecol-62.png"><IMG SRC="misc/ecol/ecol-62.png" WIDTH="600" HEIGHT="240"></A>
<P>That last browser is Opera. He's being a Valkyrie from Wagner's
<EM>The Ring</EM>. Webster's defines
<A HREF="http://www.m-w.com/cgi-bin/dictionary?va=valkyrie">valkyrie</A> as
"any of the maidens of Odin who choose the heroes to be slain in battle and
conduct them to Valhalla".
<HR NOSHADE> <!-- ****************************************************** -->
All Ecol cartoons are at
<A HREF="http://tira.escomposlinux.org/">tira.escomposlinux.org</A> (Spanish) and
<A HREF="http://comic.escomposlinux.org/">comic.escomposlinux.org</A> (English).
<P> Regarding the two main characters, Bilo and Nano, Javier writes, "Bilo and
Nano are two students who share a flat. Although their personalities are
completely different, they get along good enough. Bilo tries to keep a calm
perspective on life, but Nano is pure concentrated bad milk. I don't know much
more about them." (Spanish version:
<A HREF="http://bilo.homeip.net/ceferino/bilo-nano/bn_index.html">
http://bilo.homeip.net/ceferino/bilo-nano/bn_index.html</A>).
<P> Javier says the Ecol (the comic strip) started as a joke, "but people liked
it and now we have 1000 visits daily and 10 mirrors". Ecol (the organization) -- or
<A HREF="http://www.escomposlinux.org/">escomposlinux.org</A> as it is officially
known -- is an all-volunteer organization run on Linux boxen. The staff pay its
DSL fee out of their own pocket. Javier is preparing an article for next month
about Ecol the organization.
<P> <SMALL>These cartoons are copyright Javier Malonda. They may be copied, linked
or distributed by any means. However, you may not distribute modifications. If
you link to a cartoon, please <A
HREF="mailto:jmr@escomposlinux.org">notify</A> Javier.
</SMALL>
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2002, Javier Malonda.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 85 of <i>Linux Gazette</i>, December 2002
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
<HR>
<TABLE BORDER><TR><TD WIDTH="200">
<A HREF="http://www.linuxgazette.com/">
<IMG ALT="LINUX GAZETTE" SRC="../gx/2002/lglogo_200x41.png"
WIDTH="200" HEIGHT="41" border="0"></A>
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD WIDTH="380">
<CENTER>
<BIG><BIG><STRONG><FONT COLOR="maroon">Modern Linux Distributions and Hardware-Challenged PCs</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/johnson.richard.html">Richard Johnson</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<h2>Introduction</h2>
<p>Linux possesses a much-vaunted ability to run on just about any machine you care to throw at it. Well, I've not tried running my washing machine on it yet but I suspect that one day that time will come. In an effort to open up the joys of Linux to a wider audience, the trend in recent Linux distributions has been to wrap up the installation process with a nice user-friendly GUI. SuSE Linux is a case in point. Their installation is run through the YaST installer which sports an attractive interface and makes installing a complex operating system like Linux an almost pleasant experience. There is one drawback however - these graphical installers tend to need a certain amount of, for want of a better word, oomph in your computer. SuSE suggest, for example, that the YaST installer requires a <em>minimum</em> of 64MB RAM on your machine.</p>
<p>Once the operating system is actually installed, however, Linux is capable of running on machines that do not meet this more demanding spec. You can tailor and tweak an installation such that you will be able to get some use out of that old 486 you might have stuck in the attic, gathering dust. It could be used as a spare machine, a router, even a small web server. </p>
<p>Nonetheless, if you try and install a recent distribution of Linux on such a machine you may well find that the attractive and user-friendly installer simply refuses to run.</p>
<p>Recently I myself had occasion to install a modern Linux distro on a reasonably old machine. I had to surmount a few problems in the course of this so I've written up my experiences - in this document - in the hope that it may prove of use to others out there who also wish to put older, otherwise redundant, machines to good use.</p>
<h2>A need for an Intranet</h2>
<p>For a variety of reasons it had become clear to me that the small company for whom I work needed an intranet site available on our local area network. Nothing too complex was required, just a simple site on which to host various company documents and other information; making them readily available to everyone on the network.</p>
<p>I also realised that this would provide me with a perfect excuse to bring Linux into our otherwise Microsoft-only network.</p>
<p>In the retail business margins are always tight and we simply could not justify the cost of a new powerful machine such as would be required to run, for example, Microsoft's IIS. We did, however, have a spare PC that was currently unused. This PC was an older model which was unable to run our relatively new accounting system and so had found itself replaced and relegated to a corner of my office. I duly designated this PC as our future intranet server.</p>
<p>The spec of this box was relatively low by modern standards - in fact the operating system installed on it was MS-DOS 6.22 with Windows for Workgroups 3.11! The PC had a 200MHz Pentium MMX processor, 16MB of RAM and a relatively generous 2GB of hard disk space. I felt this was ample for the somewhat limited demands that our intranet would place on the box - at least to begin with. I knew that I would probably need to increase the amount of RAM in the box; but RAM is cheap and it would be easy to upgrade once I'd installed Linux, if need be. I decided to crack on with my installation.</p>
<h2>The distribution</h2>
<p>I needed only a relatively minimal Linux installation as the box would operate purely as a web server on the local network - installation of an X server was not required. The distribution that I decided to install was SuSE Linux 8. This was because it is the Linux distro that I use on my own PC at home and I'm familiar and comfortable with SuSE's way of doing things. I've tried a few different distros in my time and have pretty much settled on SuSE as my favourite. It was with a certain amount of relish that I set about installing a new operating system from my own set of CD's without having to worry about any visits from the licensing gestapo.</p>
<h2>The installation</h2>
<p>I booted up the PC and hit the F2 key to get into the BIOS. A quick check revealed that I could instruct the PC to boot from the cd-rom drive first so I duly set it to behave like this. I inserted disk 1 from my set of SuSE Linux disks and rebooted the PC with the new bios settings. After successfully booting from the CD I chose to do a 'standard installation' from the SuSE menu that appeared.</p>
<p>The SuSE Linux installation process begins by loading a copy of Linux into your system memory, making use of a ramdisk to provide an initial filesystem rather than using the hard disk. Or at least - it tries to. The system appeared to lock up when it tried to uncompress the ram disk into memory. After waiting a while, mindful of the low spec of the system, just to check that I wasn't simply being impatient, I hit ctrl-alt-del and the system shut itself down gracefully.</p>
<p>I tried again - booting the computer once more from the cd-rom, however this time I tried SuSE's 'safe installation'. Unfortunately the same problem manifested itself just as before. </p>
<p>I suspected that the problem was being caused by the limited physical memory on my box. A quick root around on SuSE's website revealed that the minimum memory suggested for running their setup program, as I mentioned earlier, is 64MB; which is rather more than the 16MB my poor box was blessed with.<p>
<p>Not being one to give up without a fight I booted once more from the cd-rom and hit the F2 key at the initial SuSE screen to start up the text based installation - on the hope that this would require less memory than the fancy framebuffer GUI-based installation that SuSE normally provides. It worked! The initial copy of Linux, ramdisk and all, successfully loaded into the system memory and the text-based YaST installation began. I was asked couple of questions regarding such matters as my preferred language and then...a message popped up telling me that I did not have sufficient memory to run YaST. The installation had halted once more.</p>
<p>At this stage YaST actually gave me the option of activating a swap partition to provide some virtual memory in lieu of physical memory. Unfortunately I didn't have a swap partition on this box - just one huge 2GB FAT16 DOS partition. It did, however, point up a possible solution to my problem. I realised that if I manually repartitioned my disk before actually running the YaST - providing myself with a genuine Linux swap partition - then I might actually be able to get somewhere.</p>
<h2>The Partitioning</h2>
<p>Not having access to any sophisticated partioning software, I decided to obtain a Linux boot disk with the Linux version of FDISK - so that I could roll my own partitions.</p>
<p>To this end I downloaded the truly wonderful Tom's Root Boot Disk. This provides a DOS executable that will format an ordinary 1.44MB floppy disk with a complete bootable Linux system; including a small filesystem and all the handy utilities you could need. It even includes FDISK. Tom's Root Boot Disk can be downloaded from <a href="http://www.toms.net/rb/">http://www.toms.net/rb/</a> and I cannot recommend it highly enough.</p>
<p>The DOS executable provided by Tom will not run in a command prompt on Windows 2000 - the OS on my usual desktop PC at work. Instead it requires an actual DOS operating system, so I copied the downloaded zip file onto the box that I was trying to install Linux onto - if you recall, it had MS-DOS 6.22 installed on it - and unzipped it. Rebooting a Win95/98 PC in MS-DOS mode would also provide you with a suitable environment. I stuck a floppy in the appropriate drive and let Tom's program create my boot disk for me. A painless procedure. Finally I re-booted the computer using my newly created Linux boot disk. </p>
<p>After pausing to marvel for a moment at how darned clever Tom's Root Boot Disk is, I got to work. I should mention at this point that FDISK misbehaved the first time I tried it. I thought I'd zapped the original DOS partition and created for myself a sparkling new Linux swap partition but it turned out that FDISK had misreported the number of heads, cylinders and sectors on my disk. Thus, when it wrote the new partition table it made a right pig's ear of it. I didn't realise this until YaST started throwing up bizarre errors about my disk. I rebooted with Tom's root boot and tried again. The second time around FDISK behaved itself and all was well. Though - left somewhat paranoid by FDISK's behaviour - to make sure that it was now correctly detecting the details of my hard disk I actually took the PC apart so that I could check the label on the disk itself!</p>
<p>FDISK is often cited as being a scary bit of software to use, but I've always found it to be quite straightforward myself. To launch FDISK you type:</p>
<pre>
#&gt; fdisk /dev/hda
</pre>
<p>Assuming, of course, that the hard disk to be partitioned is the first IDE disk. You have to tell FDISK which device you want to partition, in this case /dev/hda. If you have any doubts about FDISK's syntax you can check out the man page - yes, Tom's root boot disk even provides man pages for your edification and delight!</p>
<p>Once you've started up FDISK you control its behaviour with single letter commands. Type 'm' (without the quotes) for a list of the available commands. 'p' prints out the current partition details on screen for reference. </p>
<p>First you need to delete the existing partition by typing 'd' and specifying, when prompted, which partition number you wish to delete. The partition numbers are revealed when you <b>p</b>rint the partition details on screen. Bear in mind that FDISK doesn't actually make any changes to your disk until you use the 'w' command to <b>w</b>rite your changes. If you screw up you can just type 'q' to <b>q</b>uit without saving your changes. Once you have written them, however, there is no going back so be careful. New partitions are added to the disk with the 'n' command. New partitions will be normal Linux partitions by default so you'll need to use the 't' command to change the new partition's <b>t</b>ype to Linux swap. You need to know the hex code for swap partitions when you change the partition type and you can get this by using the 'l' command to <b>l</b>ist all the different partition types supported by FDSIK. Linux swap is type 82.</p>
<p>In my case I created two separate primary partitions on the disk. The first was a Linux swap partition; 128MB in size. The second partition was a standard Linux partition taking up the rest of the disk. I then formatted my partitions. For the swap partition I used the following command:</p>
<pre>
#&gt; mkswap -c /dev/hda1
</pre>
<p>This sets up a Linux swap area on partition 1 of device hda. The -c flag tells mkswap to check the partition for bad blocks. The second Linux partition I formatted as a Linux Second Extended Filesystem with the command: </p>
<pre>
#&gt; mke2fs -c /dev/hda2
</pre>
<p>The syntax, as you can see, is rather similar to the mkswap command.</p>
<h2>The installation - slight return</h2>
<p>Once I'd created my partitions I booted once more from the SuSE Linux CD - again pressing F2 to opt for the text based installation. This time, when asked if I wanted to activate a swap partition, I could specify the partition that I had just created which was located at /dev/hda1. YaST then proceeded without a hitch - if a little slowly.</p>
<p>From this point onwards the installation was relatively straightforward. SuSE's YaST is a very good setup tool striking just the right balance between sophistication and user-friendlyness, IMHO. The only problem that I needed to watch out for was with YaST's own disk partitioner. This recognised my existing partitions and suggested reformatting the second partition with the ReiserFS journalling filesystem - which I was more than happy to do - however, it also suggested reformatting the swap partition as well. I thought it best not to let it do this as I suspected it might cause problems if I tried to format a swap partition that was in active use...</p>
<h2>Conclusion</h2>
<p>YaST is good but memory hungry and it certainly made extensive use of the swap partition that I'd created. Once Linux was installed and running I was able to tune my installation to ensure that only the necessary services were running and it ran tolerably well with just the 16MB of RAM. Notwithstanding a lot of activity on the swap partition of course. </p>
<p>In the end I did install more memory in my box. This made the system more responsive and better able to cope with the demands placed upon it by multiple users over the network. Yet I was nonetheless impressed by how well Linux - which is a powerful modern operating system after all - ran on a system with such limited resources. </p>
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2002, Richard Johnson.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 85 of <i>Linux Gazette</i>, December 2002
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
<HR>
<TABLE BORDER><TR><TD WIDTH="200">
<A HREF="http://www.linuxgazette.com/">
<IMG ALT="LINUX GAZETTE" SRC="../gx/2002/lglogo_200x41.png"
WIDTH="200" HEIGHT="41" border="0"></A>
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD WIDTH="380">
<CENTER>
<BIG><BIG><STRONG><FONT COLOR="maroon">Handicapped People of the World, Unite!</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/lodato.html">Janine M Lodato</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<EM>This article explores Linux's potential role in assistive technology
(AT). AT allows those living with multiple schlerosis, other handicaps or
the affects of aging to take greater control in maintaining their health and
living independently.
</EM>
<H2>Introduction</H2>
<P> Some of the most criminal and immoral aspects of the
monopolistic practices of Microsoft, which for all
practical purposes eliminated or curtailed competition,
is the fact that PCs today are
<UL>
<LI> much too expensive.
<LI> insanely unreliable.
<LI> maddeningly complex.
</UL>
<P> These negative attributes of the Windows world
makes the PCs of today useless for the truly needy:
<UL>
<LI> the aging population.
<LI> the physically disabled.
<LI> the learning disabled.
<LI> and the professionals working with all the above.
</UL>
The sum of these people account for more than half
the population of the world. They are in need of a
collaborative assistive technology (AT) system which
operates with telephone-style simplicity. An end-to-end
AT-based collaborative system connected via the Web
will allow the professionals to provide support group-style
assistance in the form of a simple virtual community.
<P> Now that Linux is available, it is feasible to approach
this very large market using a low-cost, rugged and simple
client system. Linux-based client systems connected
to Linux servers are perfect for such end-to-end
AT systems offering. The reliable and simple features
of Linux coupled with low cost Linux based hardware
and platforms and applications are the only solution
for these end users who need AT capabilities.
<H2>The work to be done</H2>
<P> A very significant upgrade of self-supported health
improvement can be achieved using assistive
technologies (AT) connected via the Web.
Recent scientific studies by major universities
in the field of behavioral medicine including
psychoneuroimmunology (PNI) indicate that getting
involved with collaborative group activities
has significant rehabilitation potential. In fact
behavioral medicine can prevent disease, and
improve quality of life and rehabilitate.
Of course it does not replace the pharmaceuticals,
but it does improve their effectiveness.
<P> It is suggested that the collaborative virtual community
systems, based on Web-connected AT clients and servers,
supporting the disabled and the aging can also be used for
the able-bodied eyes-busy, hands-busy professionals to
improve their productivity. Also learning-disabled children
can make very good use of AT. This low cost set of AT
platforms and associated Web connectivity could be
very useful in many government and commercial employment
arenas. This dual-use type approach will significantly lower
the cost of the needed technologies for all groups.
<P> Of course there is still work to be done. Applications for AT technologies
must be developed or perfected to allow collaboration between the health
service professionals
or social worker professionals and the many people in need.
Web connected AT oriented software components running on Linux client
machines connected to Linux servers have to be created such as
<UL>
<LI> simple and application specific user interface.
<LI> voice based interaction via computer/telephone.
<LI> always-on and always-available systems.
<LI> a collaborative virtual community systems.
</UL>
<P> Through such systems the professionals can monitor,
mentor and moderate and even medicate the members
of the collaborative community. For a good example:
when dealing with students with learning disabilities, it is
important to get their attention, to bolster their behavior
and finally to improve their cognitive productivity. With
assistive technology people can prevent further destruction
of their faculties, improve their quality of life and can even be
rehabilitated somewhat. Just the idea of being productive
adds to a person's self-esteem enormously.
<H2>A personal example</H2>
<P> I have many years of personal experience using AT and found
it very helpful in SPMS (secondary progressive multiple sclerosis)
conditions as described below in a brief review of my
personal experiences.
<P> In addition to my extensive experience with AT I also have
related graduate credentials from both California State
Univ at Northridge (the center for AT corporate interactions)
as well as CSU in Sacramento and UOP in Stockton.
<P> In spite of my handicap, I find it gratifying and fulfilling to
concentrate my efforts on projects worthwhile to a very deserving community.
Involvement such as this has proved to have healing powers for me. I am
living proof of the powers of PNI based on personal involvement.
<P> Having relied on AT in order to survive my wheelchair imprisonment,
specifically voice recognition for writing, I see dual value: one for the
hands-busy, eyes-busy professionals increasing their productivity through
ease of use, and the other, of course, for use by the physically disabled.
<P> Being disabled with MS, I use IBM ViaVoice on a MAC to write. It allows
me to verbally communicate by email with my friends as well as giving me the
opportunity to express myself and get involved with worthwhile projects in
the AT arena.
<P> Typically voice recognition systems spell very well but now and then
some of them do make typos which really take the cake:
<UL>
<LI> emerge -&gt; eat March
<LI> inevitable -&gt; in edit a bowl
<LI> Nazi -&gt; not see
<LI> multiple schlerosis -&gt; multiple skull roses
<LI> idiosyncracies -&gt; HBO sink receives
<LI> A loud sneeze from my husband nearby inspires the computer to type
"aha".
</UL>
<P> I receive enduring fulfillment from developing my intellectual strengths
and putting them to positive use. I learn from my negative experiences which
have been many in my 54 years of existence and I savor my positive
experiences to learn optimism.
<P> The best way to use these intellectual strengths is to get involved with
collaborative teamwork and personal communications within the disabled
community and with companies who provide assistive technologies for this
community.
<P> It is important for me to maintain what little health I have and
to become involved in something I hold great faith in. So I have decided to
become involved in the latest AT systems available to people with
disabilities. I am especially interested in technologies that help the
disabled express themselves, such as voice recognition for writing and
voice-activated telephone service for talking.
<P> There are many AT type technologies that focus on, and make good use of
the physical abilities a disabled person may still have such as voice, lip
movement, eye motion and brain waves. These capabilities can be used with
brain-actuated computer systems and voice recognition software, to name a
few. Integrating these already-existing technologies into something usable
by disabled clients so they can express themselves will offer them freedom in
spite of their handicap.
<P> Understanding that there are companies already seeking to address this
market makes my involvement in the area that much easier and completely
natural. Finding companies geared toward brain-actuated computer control
systems is my next assignment.
<P> As a handicapped woman who still has control of her mental faculties and
voice, I have something to offer by connecting the right people so that I can
integrate systems through the Internet to develop a mutually beneficial
virtual community.
<H2>Conclusion</H2>
<P> Personal communications and collaborative teamwork need assistive
technologies to further the self-esteem of the disabled. Linux, due to its
low cost, open architecture and international development, provides an ideal
platform for building these technologies. Those living with handicaps
(and their relatives and friends) can make a unique contribution to this
effort because they know firsthand what benefits AT can provide.
<P> Involvement in AT projects can help disabled people in another way too.
Not only does it provide a distraction from their problems, but it's also a
constructive way to spend their time while furthering a cause they believe in.
<P> The positive rehabilitative effects of Behavioral Medicine is my method
of surviving and thriving until a final cure for MS is developed.
<BLOCKQUOTE><EM>
[LG would like to see additional articles and Mailbag letters
about Linux's applicability in assistive technology. If you have any
ideas, let us know. -Ed.]
</EM></BLOCKQUOTE>
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2002, Janine M Lodato.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 85 of <i>Linux Gazette</i>, December 2002
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
<HR>
<TABLE BORDER><TR><TD WIDTH="200">
<A HREF="http://www.linuxgazette.com/">
<IMG ALT="LINUX GAZETTE" SRC="../gx/2002/lglogo_200x41.png"
WIDTH="200" HEIGHT="41" border="0"></A>
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD WIDTH="380">
<CENTER>
<BIG><BIG><STRONG><FONT COLOR="maroon">So You Wanna Create Your Own x86 Operating System?</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/mahoney.html">Patrick Mahoney</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<h2>1. Introduction</h2>
One of the great difficulties a hobbyist programmer faces when trying
to start the development of his own OS is finding out where to
start. Many books describe in-depth theoretical OS concepts, yet noone
seems to take a hobyist programmer by the hand and bring him face to
face with these concepts. This is precisely what this article aims at
doing.
<p>
Several articles related to this topic appeared in the last few issues
of the Linux Gazette. I plan to approach it in a much less programming
oriented manner, only presenting to the reader the tools and tips he
will need to begin the development of his own OS. Once done with this
article, the interested reader should be all set to start browsing the
resources available to him and start designing and coding.
<p>
You might not be aware of it, but operating system development doesn't
start at the beginning. (!!) Writing a solid bootloader is a whole
project in itself, and I would not advise one to begin an OS
development project by writing a bootloader. Many reliable ones are
available for free (Grub, lilo, ppcboot, etc...). If you plan on
writing your own, I suggest you delay this task to a later stage of
the project. In this article, I will be using GNU Grub, the Grand
Unified Bootloader.
<h2>2. Description of the development environment</h2>
To ease the pain that OS development will bring to you, you will need
to set up an adapted development environment which meets a certain
number of requirements:
<p>
<ul>
<li>You should get to rapidly test your newly compiled kernel
<li>You should never have to reboot your development machine
<li>You should not need to use floppies as a storage medium for your OS
</ul>
<p>
This article will present one of many possible environments which
meets these requirements. It will consist of a development machine and
a testbed machine that both lie on a common network.
<h3>2.1 The development machine</h3>
Obviously, this machine will need to be equipped with a good set of
programming tools: assembly and C compilers, a linker and a 'make'
utility are musts.
<p>
A tool I found more useful than I initially thought it would be is an
emulator. Such a tool will help debug your kernel and will allow you
to rapidly test your newly added line of code. Don't be fooled,
though. An emulator never replaces a good ol' testbed machine.
<p>
Next, you need a TFTP server. This tool will allow your testbed machine's
tftp enabled bootloader to acquire a kernel from the development
machine via the network connection.
<h3>2.2 The testbed machine</h3>
All this machine needs is a network card and a TFTP enabled bootloader
that supports it.
<h2>3. Setup of the development environment</h2>
<h3>3.1 The development machine</h3>
The chosen programming tools are:
<ul>
<li>gcc 2.95.4
<li>ld 2.13.90.0.10
</ul>
<p>
Bochs version 1.4.1 is the chosen x86 emulator. Special care should be
taken to compile it with debugger mode enabled. These commands should do
the job:
<pre>
$ ./configure --enable-x86-debugger
$ make
</pre>
In order to properly use Bochs, you need to create a disk image. This
image needs to have both a bootloader and a filesystem. This can
be done using the <a href="misc/mahoney/mkbimage">mkbimage</a>
script. If you're too lazy to do it yourself, grab <a
href="misc/mahoney/c.img.gz">this</a> gzipped 10MB disk image and add
<pre>
diskc: file=c.img, cyl=24, heads=16, spt=63
</pre>
to your .bochrc file.
<p>
As for the TFTP server, I chose to use atftpd. It's an easy to use
linux-based TFTP server implementation.
<h3>3.2 The testbed machine</h3>
The chosen bootloader is GNU Grub version 0.92. Special care should be
taken to enable Grub's tftp client to talk to your network card. My
testbed machine has a cheap NE2000 ISA clone. Following carefully the
netboot/README.netboot instructions, I used these commands:
<pre>
$ ./configure --enable-ne --enable-ne-scan=0x220
$ make
</pre>
Note that a PnP PCI card would be easier to configure. Now, you can
either install the Grub images on the testbed machine's MBR or on a
floppy which your testbed machine will boot from. I prefer the latter,
since my testbed machine is also used for other purposes, and
therefore, I'd rather not play with its HD.
<pre>
$ cat ./stage1/stage1 ./stage2/stage2 &gt; /dev/fd0
</pre>
Now just insert your floppy in your testbed machine to see if your
network card gets recognized. You can either configure it by hand or
use a dhcp server, if any.
<pre>
grub&gt; dhcp
Probing... [NE*000]
NE2000 base 0x220, addr 00:C0:A8:4E:5A:76
Address: 192.168.22.14
Netmask: 255.255.255.0
Server: 192.168.22.1
Gateway: 192.168.22.1
</pre>
Note that you won't have to configure these parameters by hand each
time you boot. See the GNU Grub documentation and the 'grub-install'
script for details.
<p>
That's it! You're all set to test your setup!
<h2>4. Testing your development environment setup...</h2>
As I mentioned earlier, I will leave the core OS programming stuff to
the experts out there. So in order to test your setup, we will use the
example kernel from the GNU Grub sources located in the /docs directory.
<p>
The kernel is built from three source files: boot.S, kernel.c and
multiboot.h. You can build the kernel by doing:
<pre>
$ gcc -I. -c ./boot.S
$ gcc -I. -c ./kernel.c
$ ld ./kernel.o ./boot.o -o kernel -Ttext 100000
</pre>
Here's a quick and incomplete explanation. Multiboot is a standard
that defines a way for the bootloader to pass information to the
kernel it tries to load. boot.S accepts this information, sets up a
stack, and calls 'cmain'. This function sets up the vga display,
reads the information passed to him, prints some stuff and
leaves. Then, boot.S gets the control back, prints the string
'Halted.', and enters an infinite loop. Pretty simple stuff, right?
The reader is invited to dig into the code to get more details.
<h3>4.1 ...with Bochs</h3>
The plan is to mount your disk image via a loopback device, copy your
kernel on the filsystem of the image, unmount it, and fire off
Bochs. Of course, you have to add an offset to the start of the
filesystem. But you knew that, right?
<pre>
# /sbin/losetup -o 32256 /dev/loop1 ./c.img
# /bin/mount -t ext2 /dev/loop1 /mnt/osdev/
# cp <path-to-grub>/docs/kernel /mnt/osdev
# umount /mnt/osdev/
# /sbin/losetup /dev/loop1 -d
$ bochs
</pre>
Of course, that can be automated by your Makefile. Once in Grub,
simply do:
<pre>
grub&gt; kernel (hd0,0)/kernel
grub&gt; boot
</pre>
<a href="misc/mahoney/bochs_screenshot.jpg">
<img alt="Bochs screenshot" src="misc/mahoney/bochs_screenshot.jpg" width="400" height="220"></a>
<BLOCKQUOTE><EM>(Click the image for the full size.)</EM></BLOCKQUOTE>
<h3>4.2 ...with your testbed machine</h3>
First, setup your TFTP server so that the client can retrieve your
kernel:
<pre>
# /usr/sbin/atftpd --daemon /home/bono/src/grub-0.92/docs
</pre>
Fire off your testbed machine. Configure your network connection as
shown above. Next, specify your devel machine's ip address as the TFTP
server address and the location of the kernel image. Note that this
option can be set by the dhcp server. Finally, start the boot
process.
<pre>
(...)
grub&gt; tftpserver 192.168.22.36
Address: 192.168.22.14
Netmask: 255.255.255.0
Server: 192.168.22.36
Gateway: 192.168.22.1
grub&gt; kernel (nd)/kernel
[Multiboot-elf, <0x100000:0x807:0x0>, <0x101808:0x0:0x4018>,
shtab=0x106190, entry=0x100568]
grub&gt; boot
</pre>
A screen similar to that of Bochs should appear on your testbed
machine's display.
<h2>5. Where to go from here</h2>
Well you're pretty much set to start the development of your
OS. Lots of good documentation resides on the web. Browse, post,
ask, think. Monolithic or micro kernel? Segmentation or paging?
<p>
If your debugging needs come to outgrow both the emulator and your
kernel's printk's, one setup you could add to your OS is a serial
debugger. This can range from some bytes thrown on the serial port, to
a gdb-compatible remote-debugging extension. This information could be
retrieved and processed by your development machine through a
null-modem serial cable. It's a handy common practice in OS
development.
<h2>6. Resources</h2>
<ul>
<dt><li><a href="http://cwx.prenhall.com/bookbind/pubbooks/tanenbaum/">Tanenbaum' os dev book</a>
<dd>The bible of operating system development
<dt><li><a href="http://groups.google.ca/groups?q=alt.os.development">alt.os.development</a>
<dd>There, you'll find the solution to many of your problems!
<dt><li>Freenode IRC's #osdev (irc.debian.org)
<dd> Friendly folks who never go to bed!
<dt><li><a href="http://osdev.berlios.de/">A few osdev tutorials</a> including Tim Robinson's.
<dd> Tim's been there!
<dt><li><a href="http://www.nondot.org/sabre/os/articles">The Operating System Resource Center</a>
<dt><li><a href="http://inferno.cs.univ-paris8.fr/~am/tutorial/os/tutorial00.html">BosoKernel</a>
<dd>Nicely done x86 beginner's tutorial. (French)
<dt><li><a
href="ftp://download.intel.com/design/PentiumII/manuals/24319202.pdf">
Intel Architecture Software Developer's Manual Volume 3: System
Programming</a>
<dd>Don't leave home without it.
</dl>
</ul>
<h2>7. Thanks</h2>
Many thanks to all those who have accepted to patiently answer
my never-ending questions on #osdev: pavloskii, geist, oink,
byrdkernel, air.
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2002, Patrick Mahoney.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 85 of <i>Linux Gazette</i>, December 2002
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
<HR>
<TABLE BORDER><TR><TD WIDTH="200">
<A HREF="http://www.linuxgazette.com/">
<IMG ALT="LINUX GAZETTE" SRC="../gx/2002/lglogo_200x41.png"
WIDTH="200" HEIGHT="41" border="0"></A>
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD WIDTH="380">
<CENTER>
<BIG><BIG><STRONG><FONT COLOR="maroon">Viewing Faxes on the Web</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/nielsen.html">Mark Nielsen</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<ol>
<li>
<a href="#Introduction">Introduction</a></li>
<li><a href="#config">Setting up Apache 2.0</a></li>
<li><a href="#s">Suggestions for you</a></li>
<li><a href="#conclusion">Conclusion</a></li>
<li><a href="#REF">References</a></li>
</ol>
<h3>
<a NAME="Introduction"></a>Introduction</h3>
The purpose of this article is to describe a simple Perl script I use
to manage faxes on my fax server over the web. The method I use is very
crude and is only used by myself and one other person in the company
I work for,
but it works for me. With very little effort, it would be very easy to
setup professional scripts to handle faxes from small to very large
corporations. I also believe it would be very easy to setup a web interface
for other fax systems (if they don't already have it). Personally, I would
much rather send and receive faxes over a webpage because then I can access
the system (and the faxes) from anywhere in the world.
<p>
For my setup, I was using efax, which is not that easy to get along with.
For any sane person, I recommend
<a href="http://www.hylafax.org/">HylaFax</a> or some other alternative
(mgetty has some hope).
<p>
Please read my other efax article at
<a href="http://linuxfocus.org/English/July2002/article249.shtml">Linux
Focus</a>.
<h3>
<a NAME="config"></a>Configuring Apache 2.0</h3>
First, look at how I
<a href="misc/nielsen/Compile_Apache_Fax.bat.txt">compiled</a> and then
<a href="misc/nielsen/Apache.config.txt">
configured</a> Apache 2.0. This is just one installation I did, out of many.
No, Php is not running on my webserver even though the config file says I am.
<p>
I have a directory, /usr/local/apache2/htdocs/fax, where I put in my
Perl script and .htaccess files.
<p>
Underneath this directory, I have these directories:
<ul>
<li>home -- my faxes go here</li>
<li>ab -- where other Audioboomerang faxes go.</li>
<li>source -- where we have the original faxes at.</li>
<li>display -- the list of faxes yet to be viewed/archived.</li>
<li>archives -- where the ps and pdf files are archived.</li>
</ul>
I put a .htaccess in these directories to limit access by people. An example
.htaccess is
<pre>
AuthName Test
AuthType Basic
AuthUserFile /usr/local/apache2/passwords/Passwords
order deny,allow
require user mark ted
</pre>
<p>
You can change/add passwords with htpasswd.
<p>
Next, the last thing is to create a perl script.
Here is my very crude Perl script. If I ever do anything else with it,
I will convert it to a Python script first as Python is the next wave
for programming (I hope). Python, Zope, Apache, Linux, and PostgreSQL
are the top choices for my programming environment. Save it as "fax.pl"
and perform a "chmod 755 fax.pl" after saving it.
<p>
You can <a href="misc/nielsen/fax.pl.txt">download</a> it or just view it below.
<pre>
#!/usr/bin/perl
use CGI;
print "Content-type: text/html\n\n\n";
my $Home = "/usr/local/apache2/htdocs/fax";
my $Source = "$Home/source";
my $Archives = "$Home/archives";
my $AB_Archives = "$Home/ab";
my $Display = "$Home/display";
my $Home_Archives = "$Home/home";
`mkdir -p $Source`;
`mkdir -p $Archives`;
`mkdir -p $Display`;
`rsync -av /var/spool/fax/incoming/fax* $Source`;
`mkdir -p $AB_Archives`;
#------------------------------------
my @Files = &lt;$Source/fax*&gt;;
foreach my $File (@Files)
{
# print "$File\n";
my (@Temp) = split(/\//, $File);
my $File_Name = pop @Temp;
if (!(-e "$Archives/$File_Name\.pdf"))
{
print "&lt;br&gt;Processing new fax: $File\n";
my $Command = "tiff2ps $File &gt; $Archives/$File_Name\.ps";
# print "$Command\n";
`$Command`;
my $Command = "/usr/bin/ps2pdf $Archives/$File_Name\.ps $Archives/$File_Name\.pdf";
# print "$Command\n";
`$Command`;
`cp $Archives/$File_Name\.pdf $Display/$File_Name\.pdf`;
}
}
#---------------------------------------
my $query = new CGI;
my $Action = $query-&gt;param('action');
my $File = $query-&gt;param('file');
$File =~ s/[^a-zA-Z0-9\_\.]//g;
if (!(-e "$Display/$File")) {}
elsif ($Action eq "archive")
{
print "&lt;br&gt;Archiving $File\n";
`rm -f $Display/$File`;
}
elsif ($Action eq "archive2")
{
print "&lt;br&gt;Archiving $File\n";
`cp $Display/$File $AB_Archives/`;
`rm -f $Display/$File`;
}
elsif ($Action eq "archive_home")
{
print "&lt;br&gt;Archiving $File\n";
`cp $Display/$File $Home_Archives/`;
`rm -f $Display/$File`;
}
print qq(&lt;hr&gt;&lt;a href="archives/"&gt;Archives&lt;/a&gt; -- might be password protected.
&lt;br&gt;&lt;a href="home/"&gt;Home Archives&lt;/a&gt; -- might be password protected.
&lt;br&gt;&lt;a href="ab/"&gt;Audioboomerang Archives&lt;/a&gt;\n);
my $Table_Entries = "";
my @Files = &lt;$Display/fax*&gt;;
foreach my $File (sort @Files)
{
my (@Temp) = split(/\//, $File);
my $File_Name = pop @Temp;
my $Link = "&lt;a href='display/$File_Name'&gt;$File_Name&lt;/a&gt;";
my $Delete = "&lt;a href='fax.pl?action=archive&amp;file=$File_Name'&gt;archive file&lt;/a&gt;";
my $AB ="&lt;a href='fax.pl?action=archive2&amp;file=$File_Name'&gt;archive to AB&lt;/a&gt;";
my $Home ="&lt;a href='fax.pl?action=archive_home&amp;file=$File_Name'&gt;archive for Home&lt;/a&gt;";
$Table_Entries .= qq(&lt;tr&gt;&lt;td&gt;$Link&lt;/td&gt;&lt;td&gt;$Delete&lt;/td&gt;&lt;td&gt;$Home&lt;/td&gt;&lt;td&gt;$AB&lt;/td&gt;&lt;/tr&gt;\n);
}
print "&lt;table border=1&gt;&lt;tr&gt;&lt;th&gt;View Fax&lt;/th&gt;&lt;th&gt;Archive the Fax&lt;/th&gt;
&lt;th&gt;Archive to AudioBoomerang&lt;/th&gt;&lt;/tr&gt;\n";
print $Table_Entries;
print "&lt;/table&gt;\n";
if (@Files &lt; 1) {print "&lt;h1&gt; No faxes or they are all archived.&lt;/h1&gt;\n";}
</pre>
<h3>
<a NAME="s"></a>Suggestions for you.</h3>
<ol>
<li> I normally write in Python 2.2 these days, as this should be rewritten
in. I just happened to use Perl because I was testing mod_perl and
Apache 2.0. </li>
<li>Write a Python script to let people upload PostScript, images, or other
file formats that Linux can convert to tiff to send out as faxes. In addition,
the Python script should receive the telephone number, cover letter, etc.
to make the system flexible.</li>
<li> Create a Python/TK or <a href="http://wxpython.org/">wxPython</a>
script which acts as a client program to send and recieve faxes from your
Apache 2.0 server. The trick here is that people might have to create
a postscript file first to upload faxes or better yet, figure out some way
to directly print to the Python Script. </li>
<li>When you have a multiple page fax, have the Perl/Python
script on the webserver detect and order
the pages and merge them into one ps file with psmerge or other tool.
</li>
<li>Faxes can be pretty sensitive so use the secure service in Apache 2.0
for viewing or sending your faxes.</li>
</ol>
<h3>
<a NAME="conclusion"></a>Conclusion</h3>
I think it is pretty cool, and my boss thinks it is pretty cool.
I am going to switch to a different fax service because efax is hard to deal
with when sending faxes. My next goal is to make it so I can send faxes
through a webpage. I will have to set it up so that you first print your
document to a postscript file and then upload it (or upload a graphic image
or something else that Linux can convert usign a standard tool).
<p>
I am not sure what other fax setups utilize the web, but from my perspective,
I always want to have access to my faxes over the web or to send a fax
over the web.
<h3>
<a NAME="REF"></a>References</h3>
<ol>
<li>
If this article
changes, it will be available here
<a href="http://www.tcu-inc.com/Articles/31/nielsen.html">
http://www.tcu-inc.com/Articles/31/nielsen.html</a></li>
</ol>
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2002, Mark Nielsen.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 85 of <i>Linux Gazette</i>, December 2002
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
<HR>
<TABLE BORDER><TR><TD WIDTH="200">
<A HREF="http://www.linuxgazette.com/">
<IMG ALT="LINUX GAZETTE" SRC="../gx/2002/lglogo_200x41.png"
WIDTH="200" HEIGHT="41" border="0"></A>
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD WIDTH="380">
<CENTER>
<BIG><BIG><STRONG><FONT COLOR="maroon">Perl One-Liner of the Month: The Case of the Duplicate UIDs</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/okopnik.html">Ben Okopnik</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<H3>Chapter 1</H3>
<p>The e-mail was short, succinct, and got right to the point.
<BLOCKQUOTE><PRE>
Woomert -
I'll be short, succinct, and get right to the point.
Three-company merger.
Nervous sysadmin.
3000+ users.
/etc/passwd.
UIDs.
Regards,
Frink Ooblick
</PRE></BLOCKQUOTE>
<p>Woomert Foonly, the Hard-Nosed Computer Detective, chuckled to himself.
The client had been rather loud and incoherent on the phone, with "It doesn't
work!" and "I need help!" being the chief features of his conversation.
Woomert had sent Frink to the site to reconnoiter, and the above was the
highly satisfactory result. All that remained was to come up with the solution;
given that only a few short hours remained before the client shut down
for the day, Woomert decided to use his time productively. Let's see -
where was his favorite pillow?...
<H3>Chapter 2</H3>
<p>Refreshed and ready, Woomert appeared at the site, and immediately encountered
a rather excited Frink.
<p>&nbsp;- "Woomert, it's terrible! The file is far too long to search
manually, and the UIDs are all over the map. The sysadmin is contrite,
frantic, and panicked by turns, and his hair is almost all gone. What can
we do?"
<p>&nbsp;- "No worries, mate... oh, sorry. I was just in Canberra a few
hours ago, and some of the influence is still with me. I can tell you from
horrible experience that tomorrow will be even worse: I've got to be in
Dallas in the morning, New York in the afternoon, and Tel Aviv in the evening.
I would advise you to wear earplugs, or absent yourself from my environs
until the accents fade. Ah, the perils of travel..."
<p>Frink was becoming visibly upset.
<p>&nbsp;- "Woomert - you're not taking this seriously. Can't you see that
this is a major problem?"
<p>&nbsp;- "Oh, this? Relax, take it easy. It's not nearly as bad as it
looks, Frink; in fact..."
<p>Woomert deftly extracted his favorite typing gloves from his pocket
and slipped them on.
<p>&nbsp;- "...Perl makes it rather trivial. What we'll do is give the
sysadmin a couple of command-line tools that he can use to resolve this
problem, and - since he's using 'bash' - he'll be able to pull them up
with the 'up-arrow' key as he needs them. Here we go!"
<pre>
<hr width="100%">perl -F: -walne'$h{$F[2]}.="$F[0] ";END{$h{$_}=~/ ./&amp;&amp;print"$_: $h{$_}"for keys%h}' /etc/passwd
<hr
width="100%"></pre>
A list of duplicate UIDs, along with their related usernames scrolled down
the screen after Woomert pressed the "Enter"&nbsp;key. Both Woomert and
Frink noted with interest that there was a <b>triple</b> entry for UID0
-
<p><tt>0: root sashroot kill3r</tt>
<p>&nbsp;- "Well, well. Looks like somebody managed to break in and give
themselves a UID0 (root) account. 'sashroot'&nbsp;is OK - that's the 'standalone
shell'&nbsp;for those rough repair jobs - but 'kill3r'? Well, we'll let
the client know; meanwhile, on with the current problem. The sysadmin will
now have a list of all the duplicates - there don't seem to be all that
many - but searching for the next available UID&nbsp;could be a pain. So,
here's a second tool -"
<pre>
<hr width="100%">perl -wle'{getpwuid++$n&amp;&amp;redo;print$n}'
<hr
width="100%"></pre>
&nbsp;- "That should give him a good start on getting it all straightened
out. As for us - we're homeward bound!"
<H3>Chapter 3</H3>
<p>When they had returned to Woomert's house and were seated in front of
the fireplace - the night had been a cold one, and the wind whistled outside
the window - Frink looked expectantly at Woomert. Noting the look, Woomert
laughed.
<p>&nbsp;- "I know, I know. I should explain, shouldn't I? The air of mystery
is a sharp, pleasant thing, but it is as nothing compared to the pleasure
of learning. Here, let's start with the first one:
<pre>
<hr width="100%">perl -F: -walne'$h{$F[2]}.="$F[0] ";END{$h{$_}=~/ ./&amp;&amp;print"$_: $h{$_}"for keys%h}' /etc/passwd
<hr
width="100%"></pre>
"First, take a look at the command-line switches I used:"
<PRE>
-w Enable warnings
-a Autosplit (see "-F")
-l Enable line-end processing
-n Implicit non-printing loop
-e Execute the following commands
-F:&nbsp;&nbsp;&nbsp; Use ':' as the separator for the '-a' autosplit
</pre>
"If you remember our <a href="../issue84/okopnik.html">last
adventure</a>, all of the above except '-a' and '-F' are already familiar
to you. Autosplitting splits the lines read in by '-n' or '-p', using whitespace
as a default separator and saving the result in the '@F' array. '-F' optionally
redefines the separator by which to split."
<p>"Since we're reading in '/etc/passwd', let's look at the format of the
individual lines in it:"
<pre>borg:x:1026:127:All your base are belong to us!:/home/borg:/bin/bash</pre>
"There are seven standard fields, laid out as 'name - passwd - UID - GID
- GECOS - dir - shell'. The only things we're interested in for the moment
are name and UID; what I'm going to do is build a hash - a very important
data structure in Perl, one of the three basic ones - that contains the
UID (3rd field)&nbsp;as the <b>key</b>, and the name (1st field), followed
by a space, as the <b>value</b>, for all the entries in '/etc/passwd':
<pre>$h{$F[2]}.="$F[0] "</pre>
Since usernames can't have spaces in them, it makes a convenient separator.
Once that's done, I'll loop over the hash and print out any value which
contains a space followed by any character:"
<br>&nbsp;
<pre>$h{$_}=~/ ./&amp;&amp;print"$_: $h{$_}"for keys%h}</pre>
"I see you still look puzzled. Here, let me write out the above in a more
readable form:"
<p><tt>for (&nbsp;keys %h ){&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
#&nbsp;Loop over the "%h"&nbsp;hash</tt>
<br><tt>&nbsp;&nbsp;&nbsp; if (&nbsp;$h{$_} =~ / ./ ){&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
# Does the value contain a space followed by anything?</tt>
<br><tt>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; print "$_: $h{$_}\n";&nbsp;&nbsp;
#&nbsp;If so, print the UID, a colon, a space, and the value</tt>
<br><tt>&nbsp;&nbsp;&nbsp; }</tt>
<br><tt>}</tt>
<p>"If you think about it, you'll see that the only thing that will match
the above regex is a value with more than one name in it - meaning a duplicate
UID."
<p>&nbsp;- "All right - now I&nbsp;can see how you got the results. What
about the second expression, the 'next available UID'&nbsp;tool?"
<p>&nbsp;- "Ah, you mean this one:"
<p>
<hr width="100%"><tt>perl -wle'{getpwuid++$n&amp;&amp;redo;print$n}'</tt>
<br>
<hr
width="100%">
<p>"It's nothing but a short loop in which I&nbsp;check if the UID specified
by '$n' exists. If that test succeeds - meaning that there <b>is</b> a
UID equal to '$n' in use - 'redo' gets invoked, '$n' is incremented, and
the test happens again. If it fails, however, '$n' is printed to STDOUT
and the program exits. Useful, and not too complicated. Just a bit of work,
and they should have it all done. The security breach is something else,
but at least now they know about it..."
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2002, Ben Okopnik.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 85 of <i>Linux Gazette</i>, December 2002
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
<HR>
<TABLE BORDER><TR><TD WIDTH="200">
<A HREF="http://www.linuxgazette.com/">
<IMG ALT="LINUX GAZETTE" SRC="../gx/2002/lglogo_200x41.png"
WIDTH="200" HEIGHT="41" border="0"></A>
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD WIDTH="380">
<CENTER>
<BIG><BIG><STRONG><FONT COLOR="maroon">The Foolish Things We Do With Our Computers</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/orr.html">Mike ("Iron") Orr</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<H2>Washing flooded chips</H2>
By <A HREF="mailto:linux@rousselot.org">Philippe Rousselot</A>
<P> Here's what happened to me a few years ago when computers were not so cheap
and a group of 5 very old machines were worth saving from a flood.
<P> I was working in a Laboratory at the time. We had a room with 2 big
microscopes and 5 old Macs used for image analysis.
The room ended up flooded during the night after an autoclave (kind of
big pressure cooker that biologically-inclined geeks use to sterilize
things) broke down.
Although the microscopes were safe, the table with the Macs got hit. All
the machine ended up covered with a muddy rusty water.
<P> The next morning, I decided to bring the Macs to the lab to dismantle
them. By chance the drives and power supply were dry but the motherboards
were in really bad shape.
<P> I washed all the cards in distilled water and then in alcohol.
I then put them in an oven at 40 degrees Celsius for a day.
<P> Everyone was smiling at me until I rebuilt the Mac and got them running
again. At the time, I did not know that it was the way electronic boards were
washed in fact, and I was not really sure of the result before it came.
<P> In the meantime, the machines got reimbursed by the insurance that did
not consider worth getting the old one back, so we doubled our investment
in the computers.
<HR NOSHADE WIDTH="80%"> <!--*********************** -->
<H2>A foolish HDD fail</H2>
By <A HREF="mailto:onuryalazi@mersin.edu.tr">Onur Yalaz&yacute;</A>
<P> Once upon a time (maybe 4-5 years ago), I had a 80286 case for
old timess sake. But its floppy drive wasn't working. So I decided
to use my Pentium II' s floppy with it. I was trying to install a DOS
6.22 system on it think.
But i wasn't able to take the floppy out of its original case. A bit
acrobaticly I put the cases in parallel and with a long cable connected
the floppy to 286. Everything was OK.
<P> But there was something wrong. (Did I metioned the pentium was where my
father did his civil-engineering tasks?) The floppy's LED was on
continuoussly. I was in a hurry and didn't think
the cable was wrongly plugged. The PC didn't boot. The system was down.
It should be the doom. I got angry and started to hit the floppy drive
with a hammer. After that I got the idea of the cable. HIT! Everything
seemed to be ok then. But i got a damaged HDD. The HDD was below the
floppy.. The real doom :) But the good thing was that I had that drive
backed up.
<P> So never work without backups and hammers when working inside the case.
<HR NOSHADE WIDTH="80%"> <!--*********************** -->
<H2>Computer Abuse</H2>
By <A HREF="mailto:donovan@colberthouse.com">Donovan Colbert</A>
<P> Probably the most expensive learning experience in my history was hooking up
a second drive, a used 20mb Miniscribe SCSI 3.5" as the second in a chain to
my Amiga 2000 years ago. I didn't know about SCSI termination, and back
then, it was real important. I watched in dazed amazement as a single wire
on the cable smoked and burnt down toward the first drive, like the black
powder burning toward the weapons room in a Looney Toons featuring Bugs
Bunny and Yosemite Sam as the pirate. At probably the last possible second,
I broke the trance and lunged forward, groping around the back of the
machine for the power switch. I got it just in time. I only lost the 20mb
SCSI.
<P> About a year later, I got a job at a used retail computer store, and found
a dead miniscribe 20mb among the waste products. I removed the controller
card, swapped it out with the controller on my drive, and brought life back
to my drive. That evening, it was resting on the corner of a desk, and a
co-worker bumped it and it fell onto the concrete floor. That was the end of
that drive.
<P> I think I paid $200 for the drive, used. Needless to say, I
shortly became an expert in proper termination of SCSI chains. :)
<HR NOSHADE WIDTH="80%"> <!--*********************** -->
<H2>The Monster Hard Drive</H2>
By <A HREF="mailto:josef.moffett@mauripharm.com">Josef Moffett</A>
<P> Years ago now (about 1989 or so) I was the grateful recipient of an old XT
that no one wanted. I hadn't had much to do with computers up until then on
the hardware side - but this one came in pieces, so it was a matter of
getting my sleeves rolled up an' putting it all together.
<P> It was great - a complete change to the ol' Commodore 64 and plus 4 that
I'd played with before. But I kept getting this wierd problem. The hard drive (
a monster and a half) -- all of twenty megabytes, and in a double-height casing
(so it weighed a ton) -- was connected to the IDE controller card, which in
turn was seated into the motherboard). When switching on the computer
everything was fine. The old XT booted up with its old (DOS 3 I think) OS and
worked fine. But whenever I tried to format or delete any of the old stuff on
it it seemed fine until next reboot, when everything was still there. Wierd.
<P> So I took it along to a computer shop with a workshop and admitted to being
completely baffled by the phenomenon. The techie took one look at the ribbon
cable connecting the hard drive to the IDE controller and unplugged it and
plugged it so that it was seated over BOTH rows of pins. I had plugged the
cable in so that one whole row of pins had been missed.
<P> Needless to say, I was one really embarrassed teenager! Needless to say as
well that it has never happened again - some mistakes are just too stupid to
repeat!
<BLOCKQUOTE><EM>
[If you have a story about something foolish or ingenious you
did to your computer, send it to
<A HREF="mailto:gazette@ssc.com">gazette@ssc.com</A>. -Iron.]
</EM></BLOCKQUOTE>
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2002, Mike ("Iron") Orr.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 85 of <i>Linux Gazette</i>, December 2002
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<BIG><BIG><STRONG><FONT COLOR="maroon">Programming Bits: C# Data Types</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/ortiz.html">Ariel Ortiz Ramirez</A></STRONG>
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<P>
<!-- END header -->
In my <a href="../issue84/ortiz.html"> previous
article</a>, I introduced the C# programming language and
explained how it works in the context of the Mono environment, an open-source
implementation of Microsoft's .NET framework. I will now go on to some details
on the data types supported by the C# programming language.</p>
<p>In the subsequent discussion I will use the following diagrammatic notation
to represent variables and objects:</p>
<p><img border="0" src="misc/ortiz/notation.png" width="363" height="151" alt="Variable and object diagram notation."></p>
<p>The variable diagram is a cubic figure that depicts three traits (name, value
and type) relevant during the compilation and execution of a program. In the von
Neumann architecture tradition, we will consider a variable as a chunk of memory
in which we hold a value that can be read or overwritten. The object diagram is
a rounded edge rectangle that denotes an object created at runtime and allocated
in a garbage collectable heap. For any object in a certain point in time, we
know what type (class) it is, and the current values of its instance
variables.&nbsp;</p>
<h2>Type Categories</h2>
<p>In the C# programming language, types are divided in three categories:&nbsp;</p>
<ul>
<li>value types</li>
<li>reference types&nbsp;</li>
<li>pointer types</li>
</ul>
<p>In a variable that holds a <b>value type</b>, the data itself is directly
contained within the memory allotted to the variable. For example, the following
code</p>
<blockquote>
<pre>int x = 5;</pre>
</blockquote>
<p>declares an 32-bit signed integer variable, called <code>x</code>,
initialized with a value of 5. The following figure represents the corresponding
variable diagram:</p>
<p><img border="0" src="misc/ortiz/intvar.png" width="136" height="102" alt="A simple int variable diagram."></p>
<p>Note how the value 5 is contained within the variable itself.</p>
<p>On the other hand, a variable that holds a <b>reference type</b> contains the
address of an object stored in the heap. The following code declares a variable
called <code>y</code> of type <code>object</code> which gets initialized, thanks
to the <code>new</code> operator, so that it refers to a new heap allocated <code>object</code>
instance (<code>object</code> is the base class of all C# types, but more of
this latter).</p>
<blockquote>
<pre>object y = new object();</pre>
</blockquote>
<p>The corresponding variable/object diagram would be:</p>
<p><img border="0" src="misc/ortiz/objectvar.png" alt="An object diagram." width="290" height="159"></p>
<p>In this case, we can observe that the &quot;value&quot; part of the variable
diagram contains the start of an arrow that points to the referred object.
This arrow represents the address of the object inside the memory
heap.&nbsp;</p>
<p>Now, let us analyze what happens when we introduce two new variables and do
some copying from the original variables. Assume we have the following code:</p>
<blockquote>
<pre>int a = x;
object b = y; </pre>
</blockquote>
<p>The result is displayed below:&nbsp;</p>
<p><img border="0" src="misc/ortiz/copying.png" width="473" height="282" alt="Results after copying values and references."></p>
<p>As can be observed, <code>a</code> has a copy of the value of <code>x</code>.
If we modify the value of one of these variables, the other variable would
remain unchanged. In the case of <code>y</code> and <code>b</code>, both
variables refer to the same object. If we alter the state of the object using variable
<code>y</code>, then the resulting changes will be observable using variable <code>b</code>,
and vice versa.</p>
<p>Aside from references into the heap, a reference type variable may also
contain the special value <code>null</code>, which denotes a nonexistent object.
Continuing with the last example, if we have the statements</p>
<blockquote>
<pre>y = null;
b = null;</pre>
</blockquote>
<p>then variables <code>y</code> and <code>b</code> no longer refer to any
specific object, as shown below:</p>
<p><img border="0" src="misc/ortiz/nullvar.png" width="469" height="196" alt="Making references equal to null."></p>
<p>As can be seen, all references to the object instance have been lost. This
object has now turned into &quot;garbage&quot; because no other live reference to it
exists. As noted before, in C# the heap is garbage collected, which means that
the memory occupied by these &quot;dead&quot; objects is at sometime
automatically disposed and recycled by the runtime system. Other languages, such
as C++ and Pascal, do not have this kind of automatic memory management scheme.
Programmers for these languages must explicitly free any heap allocated memory
chunks that the program no longer requires. Failing to do so gives place to
memory leaks, in which certain portions of memory in a program are wasted
because they haven't been signaled for reuse. Experience has shown that explicit memory de-allocation is
cumbersome and error prone. This is why many modern programming languages (such as Java,
Python, Scheme and Smalltalk, just to name a few) also incorporate garbage
collection as part of their runtime environment.</p>
<p>Finally, a <b>pointer type</b> gives you similar capabilities as those found
with pointers in languages like C and C++. It is important to understand that
both pointers and references actually represent memory addresses, but that's
where their similarities end. References are tracked by the garbage collector,
pointers are not. You can perform pointer arithmetic on pointers, but not on
references. Because of the unwieldy nature associated to pointers, they can only
be used in C# within code marked as <code>unsafe</code>. This is an advanced
topic and I won't go
deeper into this matter at this time.</p>
<h2>Predefined Types</h2>
<p>C# has a rich set of predefined data types which you can use in your
programs. The following figure illustrates the hierarchy of the predefined data types
found in C#:</p>
<p><img border="0" src="misc/ortiz/types.png" width="576" height="226" alt="The C# type hierarchy."></p>
<p>Here is a brief summary of each of these types:</p>
<table border="0" cellpadding="10" bordercolorlight="#EBEBEB" bordercolordark="#000000" bordercolor="#FFFFFF" cellspacing="1" bgcolor="#000000">
<tr>
<th style="background-color: #C0C0C0">Type</th>
<th style="background-color: #C0C0C0">Size in&nbsp;<br>
Bytes</th>
<th style="background-color: #C0C0C0">Description</th>
</tr>
<tr>
<td bgcolor="#EBEBEB"><code>bool</code></td>
<td align="right" bgcolor="#EBEBEB">1</td>
<td bgcolor="#EBEBEB">Boolean value. The only valid literals are <code>true</code>
and <code>false</code>.</td>
</tr>
<tr>
<td bgcolor="#EBEBEB"><code>sbyte</code></td>
<td align="right" bgcolor="#EBEBEB">1</td>
<td bgcolor="#EBEBEB">Signed byte integer.</td>
</tr>
<tr>
<td bgcolor="#EBEBEB"><code>byte</code></td>
<td align="right" bgcolor="#EBEBEB">1</td>
<td bgcolor="#EBEBEB">Unsigned byte integer.</td>
</tr>
<tr>
<td bgcolor="#EBEBEB"><code>short</code></td>
<td align="right" bgcolor="#EBEBEB">2</td>
<td bgcolor="#EBEBEB">Signed short integer.</td>
</tr>
<tr>
<td bgcolor="#EBEBEB"><code>ushort</code></td>
<td align="right" bgcolor="#EBEBEB">2</td>
<td bgcolor="#EBEBEB">Unsigned short integer.</td>
</tr>
<tr>
<td bgcolor="#EBEBEB"><code>int</code></td>
<td align="right" bgcolor="#EBEBEB">4</td>
<td bgcolor="#EBEBEB">Signed integer. Literals may be in decimal (default)
or hexadecimal notation (with an <code>0x</code> prefix).&nbsp; Examples: <code>26</code>,
<code>0x1A</code></td>
</tr>
<tr>
<td bgcolor="#EBEBEB"><code>uint</code></td>
<td align="right" bgcolor="#EBEBEB">4</td>
<td bgcolor="#EBEBEB">Unsigned integer. Examples: <code>26U</code>, <code>0x1AU
</code>(mandatory <code>U</code> suffix)</td>
</tr>
<tr>
<td bgcolor="#EBEBEB"><code>long</code></td>
<td align="right" bgcolor="#EBEBEB">8</td>
<td bgcolor="#EBEBEB">Signed long integer. Examples: <code>26L</code>, <code>0x1AL
</code>(mandatory <code>L</code> suffix)</td>
</tr>
<tr>
<td bgcolor="#EBEBEB"><code>ulong</code></td>
<td align="right" bgcolor="#EBEBEB">8</td>
<td bgcolor="#EBEBEB">Unsigned long integer. Examples: <code>26UL</code>, <code>0x1AUL
</code>(mandatory <code>UL</code> suffix)</td>
</tr>
<tr>
<td bgcolor="#EBEBEB"><code>char</code></td>
<td align="right" bgcolor="#EBEBEB">2</td>
<td bgcolor="#EBEBEB">Unicode character. Example: 'A' (contained within
single quotes)</td>
</tr>
<tr>
<td bgcolor="#EBEBEB"><code>float</code></td>
<td align="right" bgcolor="#EBEBEB">4</td>
<td bgcolor="#EBEBEB">IEEE 754 single precision floating point number.
Examples: <code>1.2F</code>, <code>1E10F </code>(mandatory <code>F</code> suffix)</td>
</tr>
<tr>
<td bgcolor="#EBEBEB"><code>double</code></td>
<td align="right" bgcolor="#EBEBEB">8</td>
<td bgcolor="#EBEBEB">IEEE 754 double precision floating point number.
Examples: <code>1.2</code>, <code>1E10</code>, <code>1D</code> (optional <code>D</code>
suffix)</td>
</tr>
<tr>
<td bgcolor="#EBEBEB"><code>decimal</code></td>
<td align="right" bgcolor="#EBEBEB">16</td>
<td bgcolor="#EBEBEB">Numeric data type suitable for financial and monetary
calculations, exact to the 28th decimal place. Example: <code>123.45M</code>
(mandatory <code>M</code> suffix)</td>
</tr>
<tr>
<td bgcolor="#EBEBEB"><code>object</code></td>
<td align="right" bgcolor="#EBEBEB">8+</td>
<td bgcolor="#EBEBEB">Ultimate base type for both value and reference types.
Has no literal representation.</td>
</tr>
<tr>
<td bgcolor="#EBEBEB"><code>string</code></td>
<td align="right" bgcolor="#EBEBEB">20+</td>
<td bgcolor="#EBEBEB">Immutable sequence of Unicode characters. Example: <code>&quot;hello
world!\n&quot; </code>(contained within double quotes)</td>
</tr>
</table>
<p align="left">C#'s has a unified type system such that a value of any type can
be treated as an object. Every type in C# derives, directly or indirectly, from
the <code>object</code> class. Reference types are treated as objects simply by
viewing them as <code>object</code> types. Value types are treated as objects by
performing <i>boxing</i> and <i>unboxing</i> operations. I will go deeper into
these concepts in my next article.</p>
<h2>Classes and Structures</h2>
<p>C# allows you to define new reference and value types. Reference types are
defined using the <code>class</code> construct, while value types are defined
using <code>struct</code>. Lets see them both in action in the following
program:</p>
<blockquote>
<pre>struct ValType {
public int i;
public double d;
public ValType(int i, double d) {
this.i = i;
this.d = d;
}
public override string ToString() {
return &quot;(&quot; + i + &quot;, &quot; + d + &quot;)&quot;;
}
}
class RefType {
public int i;
public double d;
public RefType(int i, double d) {
this.i = i;
this.d = d;
}
public override string ToString() {
return &quot;(&quot; + i + &quot;, &quot; + d + &quot;)&quot;;
}
}
public class Test {
public static void Main (string[] args) {
// PART 1
ValType v1;
RefType r1;
v1 = new ValType(3, 4.2);
r1 = new RefType(4, 5.1);
System.Console.WriteLine(&quot;PART 1&quot;);
System.Console.WriteLine(&quot;v1 = &quot; + v1);
System.Console.WriteLine(&quot;r1 = &quot; + r1);
// PART 2
ValType v2;
RefType r2;
v2 = v1;
r2 = r1;
v2.i++; v2.d++;
r2.i++; r2.d++;
System.Console.WriteLine(&quot;PART 2&quot;);
System.Console.WriteLine(&quot;v1 = &quot; + v1);
System.Console.WriteLine(&quot;r1 = &quot; + r1);
}
}</pre>
</blockquote>
<p>First we have the structure <code>ValType</code>. It defines two instance
variables, <code>i</code> and <code>d</code> of type <code>int</code> and <code>double</code>,
respectively. They are declared as <code>public</code>, which means they can be accessed
from any part of the program where this structure is visible. The structure
defines a constructor, which has the same name as the structure itself and,
contrary to method definitions, has no return type. Our constructor is in charge
of the initialization of the two instance variables. The keyword <code>this</code>
is used here to obtain a reference to the instance being created and has to be
used explicitly in order to avoid the ambiguity generated when a parameter name
clashes with the an instance variable name. The structure also defines a method
called <code>ToString</code>, that returns the external representation of a
structure instance as a string of characters. This method overrides the <code>ToString</code>
method (thus the use of the <code>override</code> modifier) defined in this
structure's base type (the <code>object</code> class). The body of this method
uses the string concatenation operator (+) to generate a string of the form
&quot;(<i>i</i>, <i>d</i>)&quot;, where <i>i</i> and <i>d</i> represent the
current value of those instance variables, and finally returns the expected
result.</p>
<p>As can be observed, the <code>RefType</code> class has basically the same
code as <code>ValType</code>. Let us examine the runtime behavior of variables
declared using both types so we can further understand their differences. The <code>Test</code>
class has a <code>Main</code> method that establishes the program entry point.
In the first part of the program (marked with the &quot;PART 1&quot; comment) we
have one value type variable and one reference type variable. This is how they
look after the assignments:</p>
<img border="0" src="misc/ortiz/v1r1.png" alt="Class and structure variable diagram." width="509" height="231">
<p>The value type variable, <code>v1</code>, has its instance variables contained
within the variable itself. The <code>new</code> operator used in the assignment</p>
<blockquote>
<pre>v1 = new ValType(3, 4.2);</pre>
</blockquote>
<p>does not allocate any memory in the heap as we've learned from other
languages. Because <code>ValType</code> is a value type, the new operator is
only used in this context to call its constructor and this way initialize the
instance variables. Because <code>v1</code> is a local variable, it's actually
stored as part of the method's activation record (stack frame), and it exists
just because it's declared.&nbsp;</p>
<p>Objects referred by reference type variables have to be created explicitly at
some point in the program. In the assignment</p>
<pre> r1 = new RefType(4, 5.1);</pre>
<p>the <code>new</code> operator does the expected dynamic memory allocation
because in this case <code>RefType</code> is a reference type. The corresponding
constructor gets called immediately afterwards. Variable <code>v2</code> is also
stored in the method's activation record (because it's also a local variable)
but it's just big enough to hold the reference (address) of the newly created
instance. All the instance's data is in fact stored in the heap.</p>
<p>Now lets check what happens when the second part of the program (marked after
the &quot;PART 2&quot; comment) is executed. Two new variable are introduced and
they are assigned the values of the two original ones. Then, each of the
instance variables of the new variables are incremented by one (using the <code>++</code>
operator).</p>
<p><img border="0" src="misc/ortiz/v2r2.png" alt="Class and structure instances after copying." width="442" height="393"></p>
<p>When <code>v1</code> is copied into <code>v2</code>, each individual instance
variable of the source is copied individually into the destination, thus
producing totally independent values. So any modification done over <code>v2</code>
doesn't affect <code>v1</code> at all. This is not so with <code>r1</code> and <code>r2</code>
in which only the reference (address) is copied. Any change to the object
referred by <code>r2</code> is immediately seen by <code>r1</code>, because they
both refer in fact to the same object.</p>
<p>If you check the type hierarchy diagram above, you will notice that simple
data types such as <code>int</code>, <code>bool</code> and <code>char</code> are
actually <code>struct</code> value types, while <code>object</code> and <code>string</code>
are <code>class</code> reference types.</p>
<p>If you want to compile and run the <a href="misc/ortiz/varsexample.cs.txt">source
code</a> of the above example, type at the Linux shell prompt:</p>
<blockquote>
<pre>mcs varsexample.cs</pre>
<pre>mono varsexample.exe</pre>
</blockquote>
<p>The output should be:</p>
<blockquote>
<pre>PART 1
v1 = (3, 4.2)
r1 = (4, 5.1)
PART 2
v1 = (3, 4.2)
r1 = (5, 6.1)</pre>
</blockquote>
<h2>Resources</h2>
<dl>
<dt> <a href="http://www.go-mono.com/">http://www.go-mono.com/</a></dt>
<dd>The official Mono home page. You can find here the download and install instructions
for the Mono platform. It includes a C# compiler, a runtime environment, and
a class library.</dd>
<dt><a href="http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cscon/html/vcoriCStartPage.asp">http://msdn.microsoft.com/library/default.asp?url=/library/en-us/cscon/html/vcoriCStartPage.asp</a></dt>
<dd>General information on the C# programming language.</dd>
</dl>
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2002, Ariel Ortiz Ramirez.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 85 of <i>Linux Gazette</i>, December 2002
</STRONG></SMALL></CENTER>
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<BIG><BIG><STRONG><FONT COLOR="maroon">Qubism</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/harsem.html">Jon "Sir Flakey" Harsem</A></STRONG>
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<EM>These cartoons are scaled down to minimize horizontal scrolling.
To see a panel in all its clarity, click on it.</EM>
<P>
<A HREF="misc/qubism/qb-tuxonomy.jpg">
<IMG ALT="[cartoon]" SRC="misc/qubism/qb-tuxonomy.jpg"
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<P> More adventures of VI-Agra are in the
<A HREF="collinge.html">HelpDex</A> column this issue, and in the back
issues under both HelpDex and Qubism.
<P> All Qubism cartoons are
<A HREF="http://www.core.org.au/modules.php?name=Cartoons">here</A>
at the CORE web site.
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<BIG><BIG><STRONG><FONT COLOR="maroon">Process Tracing Using Ptrace - Part III</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/sandeep.html">Sandeep S</A></STRONG>
</CENTER>
</TD></TR>
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<P>
<!-- END header -->
<EM>The basic features of ptrace were explained in
<A HREF="../issue81/sandeep.html">Part I</A>. In
<A HREF="../issue83/sandeep.html">Part II</A>
we saw a small program which accessed the registers of a process and modified them so as to change the output of that process, by injecting some extra code. This time we are going to access the memory of a process.
The purpose of this article is to introduce a methods for infecting binaries on runtime. There are many possible areas of use for this technique. </EM>
<HR>
<H2><A NAME="s1">1. Introduction.</A></H2>
<P>We are familiar with ptrace and know the techniques of attaching a process,
how to trace it and finally to free it. We also have an idea about the
structure of the Linux binary format - ELF.
<P>
<P>Our plan is to fetch/modify a running binary. So we have to locate the
symbols inside the binary. There we need <CODE>link_map</CODE>. link_map is
the dynamic
linker's internal structure with which it keeps track of loaded libraries
and symbols within libraries.
<P>
<P>The foramt of link_map is (from /usr/include/link.h)
<P>
<BLOCKQUOTE><CODE>
<PRE>
struct link_map
{
ElfW(Addr) l_addr; /* Base address shared object is loaded at. */
char *l_name; /* Absolute file name object was found in. */
ElfW(Dyn) *l_ld; /* Dynamic section of the shared object. */
struct link_map *l_next, *l_prev; /* Chain of loaded objects. */
};
</PRE>
</CODE></BLOCKQUOTE>
<P>
<P>A small explanation for the fields.
<UL>
<LI>l_addr: Base address where shared object is loaded.
This value can also be found from /proc/&lt;pid&gt;/maps</LI>
<LI>l_name: pointer to library name in string table</LI>
<LI>l_ld : pointer to dynamic (DT_*) sections of shared lib</LI>
<LI>l_next: pointer to next link_map node</LI>
<LI>l_prev: pointer to previous link_map node</LI>
</UL>
<P>
<P>Link-map is a linked list, each item on list having a pointer to loaded
library. What we have to do is, to follow this chain, go through every
library and find our symbol. Now we have a question. Where we can find this
link_map?
<P>
<P>For every object file, there is a global offset table (GOT) which contains
many details of the binary. In GOT, the second entry is dedicated for the
link_map. So we get the address of link_map from <B>GOT[1]</B> and we go on
searching our symbol.
<P>
<H2><A NAME="s2">2. Straight to code.</A></H2>
<P>Now we have collected the basic information needed to access the memory. Let's
start now. First of all we attach the process 'pid' for tracing. Now we go for
finding out the link_map we require. You will find functions <CODE>read_data</CODE>,
<CODE>read_str</CODE> etc. These are helper functions to make working with ptrace easier.
Helper functions are self explaining.
<P>
<P>The function for locating the link_map is:
<BLOCKQUOTE><CODE>
<PRE>
struct link_map *locate_linkmap(int pid)
{
Elf32_Ehdr *ehdr = malloc(sizeof(Elf32_Ehdr));
Elf32_Phdr *phdr = malloc(sizeof(Elf32_Phdr));
Elf32_Dyn *dyn = malloc(sizeof(Elf32_Dyn));
Elf32_Word got;
struct link_map *l = malloc(sizeof(struct link_map));
unsigned long phdr_addr, dyn_addr, map_addr;
read_data(pid, 0x08048000, ehdr, sizeof(Elf32_Ehdr));
phdr_addr = 0x08048000 + ehdr-&gt;e_phoff;
printf("program header at %p\n", phdr_addr);
read_data(pid, phdr_addr, phdr, sizeof(Elf32_Phdr));
while (phdr-&gt;p_type != PT_DYNAMIC) {
read_data(pid, phdr_addr += sizeof(Elf32_Phdr), phdr,
sizeof(Elf32_Phdr));
}
read_data(pid, phdr-&gt;p_vaddr, dyn, sizeof(Elf32_Dyn));
dyn_addr = phdr-&gt;p_vaddr;
while (dyn-&gt;d_tag != DT_PLTGOT) {
read_data(pid, dyn_addr += sizeof(Elf32_Dyn), dyn, sizeof(Elf32_Dyn));
}
got = (Elf32_Word) dyn-&gt;d_un.d_ptr;
got += 4; /* second GOT entry, remember? */
read_data(pid, (unsigned long) got, &amp;map_addr, 4);
read_data(pid, map_addr, l, sizeof(struct link_map));
free(phdr);
free(ehdr);
free(dyn);
return l;
}
</PRE>
</CODE></BLOCKQUOTE>
<P>
<P>We start from the location 0x08048000 to get elf header of the process we are
tracing. We get the elf header and from its fields we can get the program header.
(The fields of headers were discussed in
<A HREF="../issue83/sandeep.html">Part II</A>.)
Once we get the program header, we go on checking for the header with dynamic
linking information. From the header/struct with dynamic linking information, we
fetch the location of the information. Go on searching until we get the base
address of global offset table.
<P>
<P>Now we have the address of GOT with us and take the second entry of GOT
(there we have link_map). From there get the address of the link_map which
we require and return.
<P>
<P>We have the struct link_map and we have to get symtab and strtab. For this,
we move to <CODE>l_ld</CODE> field of link_map and traverse through dynamic sections until
DT_SYMTAB and DT_STRTAB have been found, and finally we can seek our symbol
from DT_SYMTAB. DT_SYMTAB and DT_STRTAB are the addresses of symbol table and
string table respectively.
<P>
<P>The function resolv_tables is:
<BLOCKQUOTE><CODE>
<PRE>
void resolv_tables(int pid, struct link_map *map)
{
Elf32_Dyn *dyn = malloc(sizeof(Elf32_Dyn));
unsigned long addr;
addr = (unsigned long) map-&gt;l_ld;
read_data(pid, addr, dyn, sizeof(Elf32_Dyn));
while (dyn-&gt;d_tag) {
switch (dyn-&gt;d_tag) {
case DT_HASH:
read_data(pid, dyn-&gt;d_un.d_ptr + map-&gt;l_addr + 4,
&amp;nchains, sizeof(nchains));
break;
case DT_STRTAB:
strtab = dyn-&gt;d_un.d_ptr;
break;
case DT_SYMTAB:
symtab = dyn-&gt;d_un.d_ptr;
break;
default:
break;
}
addr += sizeof(Elf32_Dyn);
read_data(pid, addr, dyn, sizeof(Elf32_Dyn));
}
free(dyn);
}
</PRE>
</CODE></BLOCKQUOTE>
<P>
<P>What we actually do here is just reading dynamic sections one by one and checks
whether the tag is DT_STRTAB or DT_SYMTAB. If yes, we can get their respective
pointers and assign to <CODE>strtab</CODE> and <CODE>symtab</CODE>. Once the dynamic sectoins are
over, we can stop.
<P>
<P>Our next step is getting the value of symbol from the symbol table. For this we
take every symbol table entry one by one and check it whether it's a function name.
(We are interested in finding the value of a library function). If it is then
it's compared with the function name given by us. If here also they match now the
value of the symbol is returned.
<P>
<P>Now we have got the value of the symbol what we actually required. What help will
the value do for us? The answer depends upon the reader. As I have already stated
we may use this for both good and evil purposes.
<P>
<P>You might be thinking that everything is over. We forgot a step that we shouldn't
forget - detaching the traced process. This may leave the process in a stopped
state for ever and the consequences are already discussed in
<A HREF="http://www.linuxgazette.com/issue81/sandeep.html">Part I</A>.
So our last and final step is to detach the traced process.
<P>
<P>The program may be obtained from.
<A HREF="misc/sandeep/Ptrace.c.txt">Ptrace.c</A>
Almost the whole code is self explaining.
<P>
<P>Compile it by typing
<BLOCKQUOTE><CODE>
<PRE>
#cc Ptrace.c -o symtrace
</PRE>
</CODE></BLOCKQUOTE>
<P>
<P>Now we want to test the program. Run some process in some other console, come
back and type.
(Here my test program is <CODE>emacs</CODE> and the symbol I give is <CODE>strcpy</CODE>).
You may trace any program that is traceable instead of emacs and any symbol
you want to inspect.
<P>
<BLOCKQUOTE><CODE>
<PRE>
#./symtrace `ps ax | grep 'emacs' | cut -f 2 -d " "` strcpy
</PRE>
</CODE></BLOCKQUOTE>
and watch what is going on.
<P>
<H2><A NAME="s3">3. Conclusion.</A></H2>
<P>So, we come to the end of a series of three articles which has gone through
the basic programming with <CODE>ptrace</CODE>. Once you have understood the basic
concept it is not difficult to make steps by your own. More details on ptrace
and elf are available at
<A HREF="http://www.phrack.org">www.phrack.org</A>. One more thing
I have to write is that, we reached here without even mentioning a major topic.
One major feature of ptrace is its play with system calls. In User Mode Linux,
this feature is used in a large scale. I am busy with my classes and final year
project, and I promise, if time permits we will continue this series and then
we will have a look at those features of ptrace.
<P>
<P>All Suggestions, Criticisms, Contributions etc. are welcome. You can contact
me at
<A HREF="mailto:busybox@sancharnet.in">busybox@sancharnet.in</A>
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2002, Sandeep S.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 85 of <i>Linux Gazette</i>, December 2002
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
<HR>
<TABLE BORDER><TR><TD WIDTH="200">
<A HREF="http://www.linuxgazette.com/">
<IMG ALT="LINUX GAZETTE" SRC="../gx/2002/lglogo_200x41.png"
WIDTH="200" HEIGHT="41" border="0"></A>
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD WIDTH="380">
<CENTER>
<BIG><BIG><STRONG><FONT COLOR="maroon">Making a Multiple-Boot CD</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/sipos.html">Juraj Sipos</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<p>I noticed that the issue of making a multiboot CD is not very much covered
on the Internet, and if so, only sparsely. Commercial Windows vendors include
some possibility to create<74> bootable CD's in their software, but I haven't
yet seen an option to create a multiboot CD in their packages. For me creating
a bootable CD in Linux is much easier than in Windows. There are also many
free utilities that help you create a Linux bootable CD, but having a multiple
boot CD is a delicacy. You can have several versions of Linux boot images
on the CD - versions with support for journaling file systems, repair utilities,
various breeds of Linux or BSD, or even QNX, Plan9 and more. </p>
<p>Why do I thing this may be good for you? Imagine you use Linux and FreeBSD
simultaneously, you have more Linux distributions installed on your hard
disk, but something happened to your system - there is no way to access the
data anymore. Either you use a bootable diskette (but there may be many obstacles
if you work with a specific system like XFS journaling file system, for example,
or encrypted files system, and you find that you must have at least 5 Linux
bootable diskettes to suit you), or you create a multiboot CD on which you
put various breeds of Linux kernels and utilities. A little CD with 10 operating
systems on it is redemption from the illusion of this world that makes you
believe that something is always wrong.</p>
<p>I want this article to be easy, practical and intelligible for beginners,
too, and I'd like to avoid too technical language that is not understood
by many of us. This will help attract readers of various sort.</p>
<p>A bootable CD is based upon the so-called El Torrito standard - but there
are other sites that explain this. Visit, for example, <u><font size="2"
color="#0000ff">http://www.cdpage.com/Compact_Disc_Variations/danaboot.html</font></u></p>
<p>An important information for us will be that we may have up to 10 bootable
operating systems on a CD that we may boot anywhere where the boot ability
is supported by BIOS. The bootable ISO image file may be created with 1.44MB
diskette emulation, 2.88MB diskette emulation, or hard disk emulation.<2E></p>
<b>
<p>Now follows the practical guide on how to prepare a multiboot CD</p>
</b>
<p>First, you must have a bootable DOS or Linux diskette image file. An image
is a file that contains the contents of a disk or diskette. There may be
many types of image files - if you dd (disk dump) your Linux partition with
a command (let's suppose that your Linux partition is on the /dev/hda1 partition):<3A><b>
<p>dd if=/dev/hda1 of=/my_image.file</p>
</b></p>
<p>a file <b>my_image.file</b> will appear in your file system. Not every
image file is bootable - it depends on its contents, so a good idea would
be to prepare some Linux or BSD diskette image files. The simplest way would
be to download such image files from the Internet. Here is the link:</p>
<u><font size="2" color="#0000ff">
<p>http://www.ibiblio.org/pub/Linux/system/recovery/</p>
</font></u>
<p>The Ibiblio archive is very good. The image files you may download from
the above URL are prepared in such a way that they are bootable, so you don't
need to care much about building your own image. However, if you want to
make your own image, at the above URL you may also find some utilities like
Bootkit, CatRescue, SAR, disc-recovery-utils, etc., which will help you create
your own bootable diskettes (or bootable image files). </p>
<p>The files we will need for our work, in order to make a multiboot CD,
are fbsd-flp-1.0.3.bin (a bootable FreeBSD 2.8 MB diskette image), tomsrtbt,
or you may create your own images from the diskettes you already have. Put
your DOS or Linux diskette in the diskette drive and type the following command:</p>
<b>
<p>dd if=/dev/fd0 of=boot.img bs=512 count=2880<br>
</p>
</b><b> </b>
<p>A good idea would also be to visit <u><font size="2" color="#0000ff">http://freshmeat.net</font></u>
and search for a keyword "mini", so you will find even some esoteric mini
Linux distributions you normally don't hear about. </p>
<p>The site <u><font size="2" color="#0000ff">http://www.ibiblio.org/pub/Linux/system/recovery/</font></u>
contains (I deleted some stuff):</p>
<UL>
<LI>Bootkit-1.01.tar.gz
<LI>CatRescue101E.tgz
<LI>SAR-2.25.tar.gz
<LI>banshee-linux.0.61.tar.bz2
<LI>brd-2.0.tar.gz
<LI>disc-recovery-utils-1.0.tgz
<LI>fbsd-iso-1.0.3.bin.gz
<LI>fspace.tgz
<LI>genromfs-0.5.1.tar.gz
<LI>mulinux-5r0.lsm
<LI>mulinux-5r0.tgz
<LI>picoboot-0.95.tar.gz
<LI>rescue02.zip
<LI>resque_disk-2.3.99-pre9-A.tgz
<LI>rip-10.exe
<LI>rip-51.iso.bin
<LI>sash.tar.z
<LI>tomsrtbt-2.0.103.ElTorito.288.img.bz2
<LI>tomsrtbt-2.0.103.dos.zip
<LI>trccs-0.8.1r2.iso.bz2
<LI>trccs-0.8.1r2.tar.bz2
<LI>trccs-0.8.1r2_boot_disk.img.bz2
<LI>yard-2.1.tar.gz
<LI>yard-prefabs-2.tgz
<LI>zdisk-2.14.tar.gz
</UL>
<p>Some other good sites where you can download bootable diskette images:</p>
</b>
<p>LIAP (<u><font size="2" color="#0000ff">http://www.liap.eu.org/</font></u>):
LIAP is a Linux in a Pill - the site contains many 1.44MB diskette images
with various utilities and kernel breeds suitable for recovery of various
types of disasters.</p>
<p> </p>
<p>LEKA RESCUE FLOPPY (<u><font size="2" color="#0000ff">http://leka.muumilaakso.org/</font></u>):
Leka Rescue Floppy is a small 1.44Mb distribution. </p>
<p>TOMSRTBT (<u><font size="2" color="#0000ff">http://www.toms.net/rb/</font></u>):
Tomsrtbt (Tom's Root Boot) is a rescue utility, a very good one. You may also
download the 2.88MB image file from the above site.</p>
<p>You can also download bootable DOS images. Visit, for example, <u><font
size="2" color="#0000ff">http://www.bootdisk.com</font></u> and download
DOS images if you do not have them available. The site contains DOS 5.00
to 6.22, Win 95/98/Me Bootdisks, DOS/Windows 9X/2000/XP bootdisks, Win 95/98/ME
- NT4/NT5 bootdisks, DrDOS 7.X disk for Bios Flashing Basic, etc. You may
also create a FreeDOS boot diskette.</p>
<p>First, some terms. Let's see a difference between a bootable image file
of a diskette or disk and an ISO image file to be burned on a CD. What we
must have are bootable diskette image files from which we will create one
ISO image file. </p>
<p>1) You may prepare your bootable diskette images from diskettes you already
have with the command:
<p><b>dd if=/dev/fd0 of=/my_image.img</b></p>
or you may
download some bootable diskette image files from the Internet (see the links).
Make a directory in your Linux box, for example - /CD, and copy the images
to this directory (remember, you may have not more than ten bootable images).
Make sure you keep the 8.3 format for file names - 8 characters for the file
name and 3 characters for its suffix - this maximum is only for the compatibility
issue with the DOS makebt.exe program we will later use).</p>
<p>2) If you want to make use of the space on the CD (ten images of bootable
diskettes would only require about 14MB), place some other utilities in a
subdirectory, for example, /CD/Soft. An information how to access the CD
is included at the bottom of this article.</p>
<p>3) Run the following command from the /CD directory:</p>
<p> <b>mkisofs -b image.img -c boot.cat -J -l -R -r -o /cd.iso /CD</b></p>
<p> The "boot.cat" or "boot.catalog" file will be automatically created,
so you don't have to have it in your /CD directory - just type the command
as you see it - you can type the name of any image file, as long as its name
corresponds with the names of image files placed in the /CD directory. The
image file included in the above command will be the one you will boot your
CD from. The image files must have the size of 1.44MB or 2.8MB.</p>
<p>4) A cd.iso file will be created in your / directory (/cd.iso). When you
check this file and mount it (mount /cd.iso /mnt -o loop), the contents of
the ISO file should be seen in the directory where you mounted it. This ISO
image, if we burn the CD with it, will be bootable but only one image to
boot from will be available. </p>
<p>5) So we must edit the ISO image to make a multiple boot CD, thus we will
get other images to be included in the menu (0, 1, 2, 3, etc.) we will see
when we boot the CD (we will be welcomed by a multiple boot menu with options
for 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. By pressing the chosen number we will
boot the desirable operating system.</p>
<p>6) After editing it, we may now burn the CD.</p>
<p>Since I don't have the time and effort to create a Perl script that would
edit the ISO image for me and because the editing of the ISO image file may
appear complicated for some (I want this article to be as simple as possible),
it would be a good idea to use some free programs available on the Internet.
One of such free programs is makebt.exe. Some time ago, I found this free
program on some sites, but now I was unlucky to find it on the net, so I
put it on my website <u><font size="2" color="#0000ff"> http://www.tankred.sk/~juro/freebsd/makebt.zip</font></u>
where you can download it from. </p>
<p>You may run makebt.exe in DOSEMU, BOCHS emulator (<u><font size="2"
color="#0000ff">http://bochs.sourceforge.net</font></u>), or you can download
DOS system diskette images available at <u><font size="2"
color="#0000ff">http://www.bootdisk.com</font></u>, or make a FreeDOS bootable
diskette and boot your PC with it in order to run the makebt.exe utility.
If you don't have a DOS partition, the best idea would be to use DOSEMU emulator
- DOSEMU can also access Linux partitions, where you may have your CD.ISO
file waiting to be "grasped in your clever hands".</p>
<p>When you run MAKEBT.EXE at the DOS prompt, it will ask for the full path
and filename of the ISO file to be modified: you will type the name of the
ISO file with multiple boot diskette images in it, for example, CD.ISO, and
you will see the following screen:</p>
<p>-------------------------------------------------------------------------------------------------------</p>
<p>Make Multiple Boot CD-ISO Image Modifier ver 1.02</p>
<p>ISO File path and name: cd.iso</p>
<p> Bootable Disk Image Boot media type Default LBA</p>
<p> ------------------- --------------- ------- --------</p>
<p>BC ) BOOT.CAT</p>
<p> 1 ) FBSD.IMG <20><><EFBFBD> <20><><EFBFBD> <20><><EFBFBD> 1.44M Floppy <20><><EFBFBD> <20><><EFBFBD> <20><><EFBFBD>
Y</p>
<p> 2 ) LINUX.IMG <20><> <20><><EFBFBD> <20> 2.88M Floppy <20><><EFBFBD> <20><><EFBFBD>
<EFBFBD> <20> <20> -</p>
<p> 3 ) PLAN9.IMG <20><><EFBFBD> <20> <20><> 1.44M Floppy <20><> <20><><EFBFBD>
<EFBFBD><EFBFBD><EFBFBD> <20><> -</p>
<p> 4 ) QNX.IMG <20><><EFBFBD> <20><><EFBFBD> <20> <20> <20>1.44M Floppy <20><><EFBFBD>
<EFBFBD><EFBFBD><EFBFBD> <20> <20> <20> -</p>
<p> 5 ) OPENBSD.IMG <20><><EFBFBD> 2.88M Floppy <20><><EFBFBD> <20><><EFBFBD> <20> <20> <20>-</p>
<p> 6 )</p>
<p> 7 )</p>
<p> 8 )</p>
<p> 9 )</p>
<p> 10 )</p>
<p>&lt;TAB&gt; = move between fields, up/down arrows = move between rows,
F1 = Confirm</p>
<p>Press 'y' key to make this image as default boot</p>
<p> ------------------------------------------------------------------------------------------------------</p>
<p>BC stands for Boot Catalog. You just write boot.cat and don't worry about
it anymore, as you already used this string in the above mkisofs command
(it is, however, important that the ISO image file contains the string "boot.cat"
in it). Now you carefully type the names of the images. You have to type
the name of images in the DOS 8.3 format (this is a DOS restriction for file
names - the file may have only 8 characters and suffix 3 characters maximum).
</p>
<p>In the middle of the screen you will choose from 1.44MB floppy emulation,
2.88MB floppy emulation, hard disk emulation, or no emulation. We will only
use 1.44MB and 2.88MB emulation (if you want to make a hard disk emulation,
make a 650MB Linux partition and copy there the filesystem of your Linux
system you booted your hard disk from - experiment...) Use the right keyboard
arrow to select between the types of emulation. On the right of the screen
you have to choose one bootable image as the default one by pressing "Y".
</p>
<p>When you are finished, press F1 (you may try this several times, as the
program may not<6F> respond everytime). The program is intelligent - if you
typed the image file name incorrectly, you will receive a warning message
(after pressing F1). Do not include any descriptions for boot images in the
menu that follows after pressing F1, as this feature is mostly exploitable
in SCSI CD-ROMs and I haven't studied it very much. </p>
<p>That's it. Now you may burn your CD.</p>
<b>
<p>cdrecord -v speed=8 dev=0,0,0 /cd.iso </p>
</b>
<p>When you boot the CD, you will not see descriptions for operating systems,
only numbers. The first and the second number will (0,1) usually stand for
the same operating system. I had not much time to experiment with this issue,
but a good idea would be to write down the number, so that you know which
operating system you are going to boot from. </p>
<p>We deal here with diskette images and emulation, so if you boot your images
with the multiple boot CD you just created, you may access your CD-ROM by
typing "mount /dev/hdc /mnt", for example, and have also access to your /Soft
directory, where you may have other utilities you plan to work with later.
In case of a DOS system disk, you should include drivers to access the CD-ROM.</p>
<p>If you want to study or make a Linux program to patch the ISO file, you
can compare an ordinary ISO image file with one boot possibility only with
the ISO file patched by the makebt.exe utility. A good binary patcher is
a diff utility by Giuliano Pochini. Bdiff is a simple and small program for
making what the very common utilities "diff" and "patch" do with text files,
but also works with binary files. It may be downloaded from: <a
href="http://space.virgilio.it/g_pochini@virgilio.it/"><font size="2">http://space.virgilio.it/g_pochini@virgilio.it/</font></a>
- however, both ISO files must be identical. The diff utility (for comparing
files) will show you the place (offsets) where the information with a multiboot
flag was written. It is sector 17 (Boot Volume Descriptor) and the Boot Catalog
Sector. </p>
<p>I created many multiboot CD's with the above information and I have never
experienced a problem. But first, in order to avoid writing unusable CD-Rs -
I had some problems making my own OS/2 images - burn the ISO image on rewritable
CD-RW disks. Enjoy!</p>
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2002, Juraj Sipos.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 85 of <i>Linux Gazette</i>, December 2002
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
<HR>
<TABLE BORDER><TR><TD WIDTH="200">
<A HREF="http://www.linuxgazette.com/">
<IMG ALT="LINUX GAZETTE" SRC="../gx/2002/lglogo_200x41.png"
WIDTH="200" HEIGHT="41" border="0"></A>
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD WIDTH="380">
<CENTER>
<BIG><BIG><STRONG><FONT COLOR="maroon">Getting started with TUX</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/vinayak.html">Vinayak Hegde</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<h3> Meet TUX - "The Webserver" </h3>
<p align=justify>
If you did come to the site to read an article about Tux the
Penguin -- the lucky mascot of Linux -- you might be disappointed.
But don't go away just yet: read on to find what TUX the webserver
can do do for you in terms of performance and you will be
delighted. You might just discover something to hack on and tweak.
This is an article about TUX - the webserver embedded within
the Linux kernel.
</p>
<p align=justify>
The name TUX comes from 'Threaded linUX webserver'. TUX was written
by Red Hat and is based on the 2.4 kernel series. It is a kernel-space
HTTP subsystem. As you may have guessed by now TUX is released under the GNU GPL.
So in the free software tradition, you are free to tweak it and modify
it to meet your own specific needs. One of the ways of adapting TUX
for our needs ,is by writing TUX modules, which can be user-space or
kernel-space modules. The main goal behind writing TUX was to enable
high-performance webserving on Linux. This was especially important
as Linux is extremely popular in the webserver market.
</p>
<p align=justify>
TUX is not as feature-filled as Apache and has some limitations.
But nevertheless, TUX is a complete HTTP/1.1 compliant webserver
supporting HTTP/1.1 persistent (keep-alive) connections, pipelining,
CGI execution, logging, virtual hosting, various forms of modules,
and many other webserver features. TUX is now officially known as
the Red Hat Content Accelerator (RHCA).
</p>
<h3> What can TUX do for me ? </h3>
<p align=justify>
Though quite some amount of today's webcontent is dynamic generated, most of
the webcontent is static. Take for example static webpages and images. This
leads to quite a overhead as user-space webservers such as apache have to be
use some system calls for actually serving the content. The frequent context
switches between kernel-space and user-space programs is quite a performance
hit. TUX is a saviour here. TUX can be built into the monolithic kernel or
dynamically loaded as a module. The first approach is preferable for servers
which are dedicated to webserving. When built as a loadable module, it can be
dynamically inserted and removed, as when the service is started or stopped
respectively. This approach affords some amount of flexibility.
</p>
<p align=justify>
TUX is used primarily for serving static content, leaving generation and serving
of dynamic content to backend webservers such as Apache. Now, newer versions of TUX have
the capability to cache dynamic content as well. TUX modules can create "objects"
which are stored using the page cache. To respond to a request for dynamic data,
a TUX module can send a mix of dynamically-generated data and cached pre-generated
objects. Thus, most of the requests which are just "network-copy" operations can
be handled efficiently by TUX. The new version of TUX uses zero copy block IO
instead of a temporary buffer as in TUX 1.0. Also virtual hosting support has been
enhanced for TUX and the number of virtual hosts that can be supported is only
limited by disk space and RAM.
</p>
<h3> Getting started with TUX </h3>
<p align=justify>
Now that we know what TUX is capable of, we can move to installing and configuring
TUX. All the information that follows has been tested on Red Hat 7.2 with TUX-2.1.0-2.
Due to ease of use and familiarity Apache has been used as the user-space
webserving daemon.
</p>
<h4> Step 1. Installing TUX </h4>
<p align=justify>
Check whether you have tux installed using the command :-
</p>
<pre>
# rpm -q tux
</pre>
<p align=justify>
You may get messages similar to the ones below :
<ol>
<li> tux-2.1.0-2 (TUX is installed and the version number is printed)
<li> package tux is not installed (obvious!!)
</ol>
If TUX is not installed, download the rpm (or source package) you can install it
using the following command:
<ol>
<li> for RPM packages <br>
<pre>
# rpm -ivh tux-2.1.0-2.i386.rpm
</pre>
<br>
<li> for Source packages <br>
patch the kernel
<pre>
# patch -p0 < tux2-full-2.4.10
# make oldconfig (enable tux here,recompile and install the kernel)
</pre>
Install the user-space utilities
<pre>
# tar xzvf tux-2.1.0.tar.gz
# cd tux-2.0.25
# make
# make install
</pre>
</ol>
</p>
<h4> Step 2. Setting the stage </h4>
<p align=justify>
Create the directory /var/www/html (or some other directory of our choice)
and make it the root directory of TUX by changing the value
of DOCROOT in /etc/sysconfig/tux. Also you can give the path
where your CGI-scripts are stored to CGIROOT. Also the TUXTHREADS
variable can be set to an appropriate number here. Also create
the index.html page in the root directory. This will be used for
testing later.
</p>
<h4> Step 3. Starting TUX </h4>
<p align=justify>
TUX can be started by using the command. (As superuser)
<pre>
# service tux start (on RH systems)
# ./tux.init start (on non-RH systems)
# lsmod
Module size Used by
tux 75568 0
....
....
</pre>
Now point your favorite browser to localhost and you should see the
index.html page we created earlier. If not something has gone wrong
or the configuration is not proper. Check step 8 for details.
<pre>
# lynx localhost
</pre>
</p>
<h4> Step 4. Enabling Logging </h4>
<p align=justify>
By default, logging is disabled. To enable logging
and referrer logging, give the following commands.
<pre>
# echo 1 > /proc/sys/net/tux/logging
# echo 1 > /proc/sys/net/tux/referer_logging
# cat /proc/sys/net/tux/logfile
/var/log/tux (this is the default logfile)
</pre>
</p>
<p align=justify>
For each request, TUX logs the address of the requester, a date and
time stamp accurate to at least one second, specification of the file
requested, size of the file transferred, and the final status of the
request. The log files for TUX are stored in /var/log/tux (as seen above)
in binary format. In this binary format, the log files are approximately
50% smaller than standard ASCII text log files.
To view log files issue the following command
<pre>
# tux2w3c /var/log/tux
127.0.0.1 - - Wed Nov 20 00:22:24 2002 "GET /manual/sections.html HTTP/1.1" - 5523 200
127.0.0.1 - - Thu Nov 21 01:36:55 2002 "GET / HTTP/1.0" - 2890 200
127.0.0.1 - - Thu Nov 21 01:37:20 2002 "GET /manual/index.html HTTP/1.0" - 5557 200
127.0.0.1 - - Thu Nov 21 01:37:24 2002 "GET /manual/mod/index-bytype.html HTTP/1.0" - 6186 200
</pre>
The tux2w3c program converts the binary log files into into standard
W3C-conforming HTTPD log files.
</p>
<h4> Step 5. Enabling Gzip Compression </h4>
<p align=justify>
As we already know TUX is all about speeding up the response time. Using
Gzip compression, it is also possible to reduce the download time as well
as save some bandwidth. But for this feature to work the client must support
Gzip compression. By default, this data compression is disabled. To enable
it, do the following:
<pre>
# echo 1 > /proc/sys/net/tux/compression
</pre>
To enable it at startup add the following line to /etc/sysctl.conf
<pre>
net.tux.compression=1
</pre>
Also Gzip file with the extension .gz must be in the same directory as
the uncompressed versions of the pages you wish to serve.
</p>
<h4> Step 6. Tweaking TUX </h4>
<p align=justify>
We are not finished with configuration yet. There are some more interesting
features/tweaks which you can use. (Some of these are available only in
RHCA v2.2)
<ul>
<li> <b> application_protocol </b> <br>
If set to 1 this enables the RHCA FTP server. By default it is set to 1.
<li> <b> virtual_server </b> <br>
When set to 1 ,it turns on mass virtual hosting. Hosts are headers from
the browser that are directly turned into $DOCROOT/<Host> (virtual docroots)
This way any number of hosts can be served by TUX without any performance
penalty at all.
<li> <b> max_backlog </b> <br>
Maximum size of SYN backlog of the TUX listening socket. This has to be set
sensibly to prevent SYN attacks. Default is 2048.
<li> <b> http_dir_indexing </b> <br>
If set to 1, TUX will list files in readable directories if an index file
does not exist. (auto-generation of index.html)
</ul>
There are lots of more parameters that can be configured to maximize the
performance of the TUX webserver. Explore and tweak them to your heart's
content.
</p>
<h4> Step 7. Configuring Apache to work with TUX </h4>
<p align=justify>
As mentioned before, the recommended configuration is to use TUX as a
front-end Web server listening on port 80(the default http port) and to
use a back-end Web server (Apache is used here as an example) on port 8080
for answering requests that TUX does not understand (generally dynamically
generated content eg.PHP pages). For this configuration, some changes have to be made to
the httpd.conf file of Apache webserver.
<pre>
Replace the line
Port 80
with
Port 8080 (port on which Apache will listen)
</pre>
Also to prevent users from bypassing TUX and directly accessing apache
make the following changes. This may be necessary for security reasons.
<pre>
Replace the line
BindAddress *
with
BindAddress 127.0.0.1 (loopback address)
</pre>
Finally, restart httpd using
<pre>
# service httpd restart
</pre>
</p>
<h4> Step 8. Debugging and Restarting TUX </h4>
<p align=justify>
You can stop/restart TUX using the following commands:
<pre>
# service tux stop (for RH-Systems)
OR
# ./tux-init stop (for non-RH Systems)
# service tux restart
OR
# ./tux-init restart
</pre>
For debugging purposes you can use the <i> gettuxconfig </i> script in the
/usr/share/doc/tux-version/ directory. If you have an SMP system
you can check whether all the interfaces have been setup properly using the
<i> checkbindings </i>scripts. It is also present in the same directory.
</p>
<h3> Conclusion </h3>
<p align=justify>
As we have seen above, TUX helps a lot to improve the efficiency of
webservers by shifting some of the operations from user-space to
kernel-space. This results in better performance and better use of server
resources. TUX is very configurable and has a number of interesting features.
Hope you enjoyed the article. Happy Hacking!!
</p>
<h3> Resources </h3>
<ul>
<li> <a href=http://www.redhat.com/services/techsupport/rhca/> Red Hat TechSupport for TUX (RHCA)</a>
<li> <a href=http://people.redhat.com/~mingo/TUX-patches/>Latest Patches for TUX </a>
<li> Local Documentation in /usr/share/doc/tux-version/
</ul>
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Published in Issue 85 of <i>Linux Gazette</i>, December 2002
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<ul>
<li><a HREF="#wacko">Wacko Topic of the Month</a>
<li><a HREF="#nottag">Not The Answer Gang</a>
<li><a HREF="#spam">World of Spam</a>
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<a name="wacko"></a>
<P> <hr> <P>
<!--====================================================================-->
<center><H3><font color="maroon">Wacko Topic of the Month</font></H3></center>
<P> <HR> <P>
<!--======================================================================-->
<A HREF="steve.cody@controlsoft.com.au">Steve Cody</A> sent in a few more
additions to
<A HREF="../issue45/orr.html">If Operating Systems Ran The Airlines</A>.
<H4>Windows 3.0 Air</H4>
An old 'air DOS' biplane painted to look like a modern aircraft.
<H4>Windows 3.11 Air</H4>
As above but fitted with a two-way radio.
<H4>Sun Air</H4>
An expensive Concorde that travels only between destinations
that the average person has never been to and could never afford to go to.
<H4>ROM DOS air (a.k.a. TRSDOS, et. all)</H4>
A paper aeroplane. Hey, it flies doesn't it? What more do you want?
<H4>Altair Air</H4>
A pile of timber, wires and nails at the end of the runway,
and a nice brochure.
<HR> <!-- ************************************************************** -->
<P> Happy Linuxing!
<P> Mike ("Iron") Orr<br>
Editor, <A HREF="http://www.linuxgazette.com/"><i>Linux Gazette</i></A>, <A
HREF="mailto:gazette@ssc.com">gazette@ssc.com</a>
<BR CLEAR="all">
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