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<H2>February 2003, Issue 87 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Published by <I>Linux Journal</I></H2>
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<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="bint.html">The Ultimate Editor</A>, <EM>by Stephen Bint</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="howell.html">Quick-Start Networking</A>, <EM>by Edgar Howell</EM>
<LI> <A HREF="jenkins.html">A Keep-Alive Program You Can Run Anywhere</A>, <EM>by Graham Jenkins</EM>
<LI> <A HREF="lodato.html">Linux-Based Voice Recognition</A>, <EM>by Janine M Lodato</EM>
<LI> <A HREF="okopnik.html">Perl One-Liner of the Month: The Adventure of the Arbitrary Archives</A>, <EM>by Ben Okopnik</EM>
<LI> <A HREF="pramode.html">Fun with Simputer and Embedded Linux</A>, <EM>by Pramode C.E</EM>
<LI> <A HREF="qubism.html">Qubism</A>, <EM>by Jon "Sir Flakey" Harsem</EM>
<LI> <A HREF="ramankutty.html">Yacc/Bison - Parser Generators - Part 1</A>, <EM>by Hiran Ramankutty</EM>
<LI> <A HREF="sunil.html">I Built a Custom Debian CD from Knoppix</A>, <EM>by Sunil Thomas Thonikuzhiyil</EM>
<LI> <A HREF="vinayak.html">Encryption using OpenSSL's crypto libraries</A>, <EM>by Vinayak Hegde</EM>
<LI> <A HREF="lg_backpage.html">The Back Page</A>
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<H3 ALIGN="center"><EM>Linux Gazette</EM> Staff and The Answer Gang</H3>
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<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
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<BIG><BIG><STRONG><FONT COLOR="maroon">The Mailbag</FONT></STRONG></BIG></BIG><BR>
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<BIG><STRONG><FONT COLOR="maroon">HELP WANTED : Article Ideas</FONT></STRONG></BIG>
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<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>H/W detection in Debian ?</strong></a>
<li><A HREF="#wanted.2"
><strong>ppp over nullmodem cable - no response to (LCP ConfReq ...)</strong></a>
<li><A HREF="#wanted.3"
><strong>How can we block mails from users using ipchains</strong></a>
<li><A HREF="#wanted.4"
><strong>dual boot problem</strong></a>
<li><A HREF="#wanted.5"
><strong>Custom kernel, not so custom modules</strong></a>
<li><A HREF="#wanted.6"
><strong>ipchains vs iptables</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">H/W detection in Debian ?</FONT></H3>
Sat, 11 Jan 2003 19:06:15 +0530
<BR>Joydeep Bakshi (<a href="mailto:linux-questions-only@ssc.com?cc=joy12@vsnl.net&subject=%20Re%3A%20%5BLG%2087%5D%20help%20wanted%20%231">joy12 from vsnl.net</a>)
<P>
Hi all,
</P>
<blockQuote><ol>
<LI>kudzu is the DEFAULT H/W detection tool in RH &amp; harddrake in MDK. is there
anything in debian?
<LI>I have installed <EM>kudzu</EM> in debian 3.0 , but it is not running as a
service. it needs to execute the command <EM>kudzu</EM> manually. more over it
couldn't detect my epson C21SX printer. but under MDK 9.0 kudzu detected the
printer . any solution please ?
</ol></blockQuote>
<P>
thanks in advanced.
</P>
<!-- end 1 -->
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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">ppp over nullmodem cable - no response to (LCP ConfReq ...)</FONT></H3>
Tue, 31 Dec 2002 16:45:02 +0100
<BR>Josef Angermeier jun. (<a href="mailto:linux-questions-only@ssc.com?cc=josef.angermeier@web.de&subject=%20Re%3A%20%5BLG%2087%5D%20help%20wanted%20%232">josef.angermeier from web.de</a>)
<P>
hi linux gazette
</P>
<P>
first thanks for your great work.
</P>
<P>
id like to connect over a serial cable to a windows 2000 ras server. i
already know that the problem isnt the null modem cable, because i just
could remote control my second computer while using getty and windows's
hyperterminal on the other side. (btw i first tried gnu/linux's minicom
instead of window's hyperterminal but it seemed to me minicom just works
with a modem a the end of the cable, am i wrong or is there any other
program out there which i should give a try ?) ok ive already read those
Serial-* and PPP* howto but i probably missed something. further, i also set
the same baud rate at the ras server side. so any idea, why i
dont get any reply to my LCP ConfReq Request ??
</P>
<P>
greets
</P>
<P>
josef
</P>
<blockquote><pre>melee:/home/josef/tmp# pppd /dev/ttyS0 nodetach
Serial connection established.
using channel 1
Using interface ppp0
Connect: ppp0 &lt;--&gt; /dev/ttyS0
sent [LCP ConfReq id=0x1 &lt;asyncmap 0x0&gt; &lt;magic 0x143c91f8&gt; &lt;pcomp&gt; &lt;accomp&gt;]
sent [LCP ConfReq id=0x1 &lt;asyncmap 0x0&gt; &lt;magic 0x143c91f8&gt; &lt;pcomp&gt; &lt;accomp&gt;]
sent [LCP ConfReq id=0x1 &lt;asyncmap 0x0&gt; &lt;magic 0x143c91f8&gt; &lt;pcomp&gt; &lt;accomp&gt;]
sent [LCP ConfReq id=0x1 &lt;asyncmap 0x0&gt; &lt;magic 0x143c91f8&gt; &lt;pcomp&gt; &lt;accomp&gt;]
....
</pre></blockquote>
<P>
my <TT>/etc/ppp/options.ttyS0</TT>
</P>
<blockquote><pre>connect 'chat -v -f /etc/ppp/scripts/winserver.chat'
19200
debug
crtscts
local
user josef
noauth
</pre></blockquote>
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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 we block mails from users using ipchains</FONT></H3>
Sun, 5 Jan 2003 22:33:43 -0800
<BR>Dan Wilder (<a href="mailto:linux-questions-only@ssc.com?cc=vinod@globaledgesoft.com&cc=dan@ssc.com&subject=%20Re%3A%20%5BLG%2087%5D%20help%20wanted%20%233">SSC sysadmin</a>)
<BR>Question by linux-questions-only@ssc.com, vinod (vinod from globaledgesoft.com)
<P><STRONG>
HI,
</STRONG></P>
<P><STRONG>
I would like to know how to block mails from other users on the same
system.I tried using 'ipchains' &amp; port no,but it didnt work.Please help
me with this.
</STRONG></P>
<P><STRONG>
Thanks
</STRONG></P>
<P>
Perhaps you could be more specific about what you're trying to accomplish.
For example:
</P>
<blockQuote><ul>
<LI>I wish to block all mail from a specific user to me
<LI>I wish to prevent a specific user from sending any mail
<LI>I wish to allow users to send mail, but not to other users
on the same system
<LI>I wish to prevent any mail from being sent on the system
<LI>??
</ul></blockQuote>
<blockquote><font color="#000066">I'll take this one to the readership as a general request for more
articles about setting up mail systems to do interesting things. In
fact, some things that aren't really about spam could be a fun read
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle">
-- Heather</font></blockquote>
<!-- 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">dual boot problem</FONT></H3>
Mon, 6 Jan 2003 14:29:33 -0500
<BR>Faber Fedor (<a href="mailto:linux-questions-only@ssc.com?cc=Lazybum@sio.midco.net&cc=faber@linuxnj.com&subject=%20Re%3A%20%5BLG%2087%5D%20help%20wanted%20%234">faber from linuxnj.com</a>)
<BR>Question by Phil Harold (Lazybum from sio.midco.net)
<P><STRONG>
I installed Redhat 8.0 on an existing system that has XP pro on it. XP
is on ide0 and the Redhat is on ide1 XP hard drive is fat file system.
When it boots it asks go to Redhat or dos<6F> I don<6F>t have dos. How do I
get back to the windows? What needs to be done to change the boot
loader. I thought I had set it up so Linux only booted with a floppy<70> I
guess not
Thanks for any help.
Phil Harold
</STRONG></P>
<P>
Go ahead and choose "DOS". That will boot into the other partition
which is set up (hopefully) to boot XP.
</P>
<blockquote><font color="#000066">Looks normal so far. Hardly worthy of the "help wanted" section here
at the <EM>Gazette</EM> ... but nope, it's a stumper.
-- Heather</font></blockquote>
<P><STRONG>
just before the other symbols it says:
</STRONG></P>
<P><STRONG><BLOCKQuote>
root no verify (hd2,0)
chainloader +1
</BLOCKQuote></STRONG></P>
<P><STRONG>
hit the enter key is when the symbols come looks like greek and chinese
</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">Custom kernel, not so custom modules</FONT></H3>
Fri, 10 Jan 2003 18:25:16 +0100
<BR>Eduardo (<a href="mailto:linux-questions-only@ssc.com?cc=edlm@wanadoo.es&subject=%20Re%3A%20%5BLG%2087%5D%20help%20wanted%20%235">edlm from wanadoo.es</a>)
<blockquote><font color="#000066">An old question - he had said this relates to
[[<A HREF="../issue64/tag/16.html"
>http://www.linuxgazette.com/issue64/tag/16.html</A>][issue 64 #16 in The Answer Gang]] - but still a stumper. We have a lot more readers now;
maybe one of you knows what happened here?
-- Heather</font></blockquote>
<P>
Hello all,
</P>
<P>
I have exactly the same problem described by Michael Hansen. Modules
doesn't load after recompile Kernel. I'm also a newbie in Linux, but I
see (If you are using red hat at least), it creates a directory
<TT>/lib/modules/2.4.xcustom</TT> (in fact kernel version pass to 2.4.18custom in
my case), but when you do make modules it copies to directory 2.4.x. If
you rename directories the problem comes when you try to install a new
driver that use uname -r command during installation to find modules
directory (uname -r result is 2.4.xcustom). I don't know how solve
this problem.
</P>
<P>
Best regards
</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">ipchains vs iptables</FONT></H3>
Wed, 22 Jan 2003 14:39:11 +0100
<BR>Dean Buhrmann (<a href="mailto:linux-questions-only@ssc.com?cc=d.buhrmann@chello.nl&subject=%20Re%3A%20%5BLG%2087%5D%20help%20wanted%20%236">d.buhrmann from chello.nl</a>)
<P>
Dear Answer Gang members,
</P>
<P>
I have a linux home network which is connected to the internet through a
gateway. This computer runs linux with a 2.2.18 kernel. I use IP-chains to
block some unwanted incoming traffic.
One of the machines runs mldonkey. This program needs the ports 4161 and 4162.
I get the following error from server i contact:
</P>
<blockquote><pre>ERROR: Your port 4662 is not reachable. You have a LOWID.
</pre></blockquote>
<P>
This port is open. The solution to this problem seems to be to redirect
incoming packets from the internet for port 4662 directly to the machine
where mldonkey runs.
</P>
<P>
The following iptable should do this:
</P>
<blockquote><pre>iptables -A PREROUTING -t nat -p tcp -d $4 --dport 4662 -j DNAT --to 192.168.1.100
</pre></blockquote>
<blockquote><code><font color="#000033"><br>$4 is the gateway
<br>192.168.1.100 runs mldonkey
</font></code></blockquote>
<P>
I use a 2.2.18 kernel with ipchains on the gateway. In Howto's and other
documentation i can't find a way to do this with ipchains. Do you know if
it's possible and how?
</P>
<P>
Please your help.
</P>
<P>
greetings Dean Buhrmann.
</P>
<blockquote><font color="#000066">Articles about trevails, with details are always welcome when you solve
a strange problem. Of course there are HOWTO's for ipchains and for
netfilters, but perhaps we could see an article about do something
complicated enough to illustrate differences that might have you prefer
one or the other interface.
-- Heather</font></blockquote>
<!-- end 6 -->
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<BIG><STRONG><FONT COLOR="maroon">GENERAL MAIL</FONT></STRONG></BIG>
<BR>
</center><HR>
<UL>
<!-- index_text begins -->
<li><A HREF="#mailbag.1"
><strong>Re: your mail</strong></a>
<li><A HREF="#mailbag.2"
><strong>POS Software in Linux</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">Re: your mail</FONT></H3>
Mon, 20 Jan 2003 11:45:17 -0500
<BR>Ben Okopnik (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2087%5D%20mailbag%20%231">the <em>LG</em> Answer Gang</a>)
<BR>Question by Larry Leeds (lleeds from cableone.net)
<P><STRONG>
I had an IBM 20G hard drive that had a lot of bogus information in the
master boot record due to formatting it with 2G jumper on and then
formatting with the jumper off. It wouldn't load an OS, and it locked up
every time I tried to run fdisk, norton disk doctor couldn't fix it either,
but your little DOS assembly program
<A HREF="../issue63/okopnik.html"
>http://www.linuxgazette.com/issue63/okopnik.html</A> saved my hard drive.
</STRONG></P>
<P><STRONG>
Thank you!
</STRONG></P>
<P>
Glad you found it useful, Larry. A number of people have written in with
comments like yours about that particular article; I find it very
pleasant that my work has benefitted that many people.
</P>
<P>
I appreciate your letting me know.
</P>
<!-- 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">POS Software in Linux</FONT></H3>
Tue, 21 Jan 2003 21:07:25 -0500
<BR>Ben Okopnik (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2087%5D%20mailbag%20%232">the <em>LG</em> Answer Gang</a>)
<BR>Question by Stelian Iancu (stelian.iancu from gmx.net)
<P><STRONG>
Hi!
</STRONG></P>
<P><STRONG>
I was reading the December 2002 issue of LG (btw, great magazine! I've
just re-discovered it, and it's fantastic!) and I saw the PC-MOS thread
originated by Reilly Burke.
</STRONG></P>
<P><STRONG>
I remembered that I saw something like a prototype for a POS software on
the net and I went searching for it. The address is
<A HREF="http://www.dnalounge.com/backstage/src/pos"
>http://www.dnalounge.com/backstage/src/pos</A> and the author is no other
than jwz (Jamie Zawinski).
</STRONG></P>
<P><STRONG>
As fas as I can see, there is only an idea and a "little prototype" (as
the author describes it), but maybe this prototype can be used for
further developement by somebody else.
</STRONG></P>
<P><STRONG>
HTH!
</STRONG></P>
<P>
If you need a restaurant-specific POS and don't mind going commercial
(for a very small fee as compared to other POSes, actually), I have only
good things to say about the ViewTouch POS
&lt;<A HREF="http://www.viewtouch.com/"
>http://www.viewtouch.com</A>&gt; in
spite of its closed-source nature. The interface is <EM>very</EM> well
thought-out and beautifully done; the layout, menu, employee, and
ingredient list configuration is a snap. It supports all the popular
touchscreens, industry-standard narrow printers, and all the standard
cash drawers. Despite the documentation that insists on "RedHat-only"
compatibility, I've run it under <A HREF="http://www.debian.org/">Debian</A> from day one (three years or so
ago), and it works fine.
</P>
<P>
My biggest concern with it, of course, is that it <EM>is</EM> closed-source. I
would have liked to tweak some minor features for the client I had who
was interested; as well, I wonder what would happen if the developer
disappeared off into the ether... but that's the nature of that
particular beast. It is, however, an interesting and well-executed
option. Interestingly enough, I spotted a major restaurant near
Baltimore (a Brazilian steakhouse in Columbia, MD) using it about a year
ago. The employees using it didn't have any negative comments, either.
</P>
<P><STRONG>
P.S. Keep up the good work!
</STRONG></P>
<P>
Thanks, Stelian. That's the reality <EM>and</EM> the plan.
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle">
</P>
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><strong>Wanted: Proofreaders</strong></a>
<li><A HREF="#gaz.1"
><strong>Compilation Problem in Writing Your Own Toy OS (PART II)</strong></a>
<li><A HREF="#gaz.2"
><strong>publishing</strong></a>
<!-- index_text ends -->
</UL>
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="gaz.0"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">Wanted: Proofreaders</FONT></H3>
Thu Jan 30 11:24:03 PST 2003
<BR>LG Editor Iron (<a href="mailto:gazette@ssc.com">gazette from ssc.com</a>)
<P>
LG is looking for proofreaders. The main qualifications are a good command of
English grammar, a native or near-native sense of English word usage, and the
ability to recognize and clarify phrases that are too academic, not
understood outside their own country, or unnecessarily difficult for those
with limited English ability to read.
<P> Depending on the number of proofreaders, the workload would be at most
one article per month, but more likely one article every 2-3 months. Of
course, you would be able to refuse articles you don't have time to
proofread, or if you're not interested in the subject.
<P> If interested, send <A HREF="mailto:gazette@ssc.com">gazette@ssc.com</A>
some samples or URLs of stuff you've written or proofread (any topic, any
length) that demonstrates your wording style.
<!-- end 0 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="gaz.1"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">Compilation Problem in Writing Your Own Toy OS (PART II)</FONT></H3>
Thu, 19 Dec 2002 07:15:59 -0800 (PST)
<BR>Mohammad Moghal (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2087%5D%20gazette%20matters%20%231">riazdat from yahoo.com</a>)
<P>
Dear Sir,
</P>
<P>
"Writing Your Own Toy OS" is a Great Contribution towards knowledge.
</P>
<P>
I have tried PART I successfully.
</P>
<P>
But, after compiling part II, I booted my system from Drive A. System checked Drive A and was hangged. There was no output of the string.
</P>
<P>
Could you please help me out.
</P>
<P>
Best Regards
</P>
<P>
M. R. Moghal
</P>
<blockquote><font color="#001F3F">Forwarding to the author, Krishnakumar R.
</font></blockquote>
<blockquote><font color="#001F3F">He fixed one of the programs somewhere in the series after it was published,
but I don't remember exactly where. If you're reading on a mirror, check the
main site, and see whether that program has been changed.
<A HREF="../issue79/krishnakumar.html"
>http://www.linuxgazette.com/issue79/krishnakumar.html</A>
-- Mike</font></blockquote>
<!-- end 1 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="gaz.2"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">publishing</FONT></H3>
Fri, 27 Dec 2002 03:37:09 -0500
<BR>Mike Orr (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2087%5D%20gazette%20matters%20%232"><em>Linux Gazette</em> Editor</a>)
<BR>Question by Felix F. (felix from pz4.org)
<!-- sig -->
<!-- sig -->
<blockquote><font color="#000066">Readers, please note that this was actually an exchange of mails back
and forth between Mike and Felix, rather than one message which Mike
responded to in gory detail. If anyone out there, either in whole or
in part, takes on the Herculean task of providing paper editions of <EM>LG</EM>
please let us know - we will very happily spread the word!
-- Heather</font></blockquote>
<P><STRONG>
Have you ever thought of publishing the gazette and require subscriptions? I
would sure like to get a monthly magazine then browsing the gazette online.
</STRONG></P>
<P>
We've had several requests for a print version of LG. However, the cost of
producing it would be prohibitive. (Printing, postage, software to track
subscriptions, customer service staff, etc. And if you want a glossy magazine
rather than just a xerox copy, there's layout costs, more printer's fees, etc.)
Commercial magazines like our <I>Linux Journal</I> can do it because most of
their revenue comes from advertising, but Linux Gazette does not
accept advertising (except sponsorships).
</P>
<P>
We have repeatedly asked if any readers would be willing to set up their own
print-and-distribute service for LG, but nobody has offered.
</P>
<P><STRONG>
What kind of equipment would be required to print-and-distribute services?
</STRONG></P>
<P>
At minimum, a lazer printer, envelopes, stamps, and a list of subscribers.
That's how small, do-it-yourself zines work. You'd want some kind of
cover or binding unless you're just going to send a stack of loose sheets.
</P>
<P>
But mailing costs alone will soak you, especially since a single issue of LG
is something like fifty printed pages. (I've never printed an issue, so that's
an estimate.) Sending fifty pages via first-class mail within the US is $3-4,
so that's $48/year. Would you pay $48 for LG? You may be able to get a better
deal with book rate or presorted rate but you'd have to check with the post
office. But how will you recoup your cost for toner cartridges, paper, printer
repair/replacement (since it will wear out sooner), envelopes, and the time to
write the addresses or attach labels, not to mention the time dealing with
subscription requests, complaints about "I didn't receive my issue", etc?
</P>
<P><STRONG>
Today many free magazines put ads into the magazine and make money to
publish the magazine. It would be a good idea to maybe advertise, but
I'm not sure if LG has a high number of subscribers. I can see where the
management issue would be a problem (billing, distributing, etc).
Hopefully one day maybe.
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle">
</STRONG></P>
<P>
LG has a huge number of readers all over the world. I don't know the number
because people who read via mirrors or off-line are uncountable. But there
are mirrors in fifty countries, and I figure any country with a mirror must
have a subtantial LG readership. Either that, or it at least has one LG
fanatic....
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle">
</P>
<P>
You bring up an interesting point. LG itself is not interested in running
ads, at least not at present. I like to think of LG as an ad-free zone, a
safe haven from ads. But since LG content is freely redistributable, there's
nothing prohibiting a print-and-deliver service from inserting ads in their
version.
</P>
<P>
Actually, our author Alan Ward in Andorra said he's seen a Spanish print
version of LG on the newsstands there. I assume it was the Spanish
translation of <I>Linux Journal</I>, which may include some LG articles.
</P>
<P><STRONG>
I've seen few sites publishing their works into magazine (including ads)
and subscribers did not get angry at the ads, because they understood that
to publish costs money and if the work is quality it's worth subscribing
for.
</STRONG></P>
<P><STRONG>
HAPPY NEW YEAR and good luck.
</STRONG></P>
<P>
There <EM>are</EM> a few articles in LG that may not be redistributed in a
commercial print publication (where "commercial" means you're charging any
amount of money for it). Those articles have a message to that effect at the
bottom of the article. The ones that come to mind are:
</P>
<ul>
<LI>Some of Shane Collinge's HelpDex cartoons: he sold the print rights to a
certain publisher. This affects only a limited number of cartoons. <P>
<LI>One or two other articles that have corporate ownership.
</ul>
<P>
In those cases, you will have to contact the author for permission.
</P>
<!-- end 2 -->
<!-- *** 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; 2003
<br>Copying license <A HREF="http://www.linuxgazette.com/copying.html">http://www.linuxgazette.com/copying.html</A>
<BR>Published in Issue 87 of <i>Linux Gazette</i>, February 2003</H5>
</STRONG></SMALL></CENTER>
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<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>
<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>Two Sound Cards Under Linux</strong></a>
<li><A HREF="#tips.2"
><strong>rpm in debian ?</strong></a>
<li><A HREF="#tips.3"
><strong>propagating ownership and permissions</strong></a>
<li><A HREF="#tips.4"
><strong>boot to windows by default</strong></a>
<li><A HREF="#tips.5"
><strong>network programming - accepting data</strong></a>
<li><A HREF="#tips.6"
><strong>Key bindings in X</strong></a>
<li><A HREF="#tips.7"
><strong>alsa in debian</strong></a>
<li><A HREF="#tips.8"
><strong>pppd</strong></a>
<li><A HREF="#tips.9"
></a>telnet processes not disappearing when user closes session incorrectly --or--
<br><A HREF="#tips.9"
><strong>Is that your FIN_WAIT Answer?</strong></a>
<li><A HREF="#tips.10"
><strong>direct rendering for nvidia RIVA 128</strong></a>
<li><A HREF="#tips.11"
><strong>xcdroast post cdrom mount problem</strong></a>
<li><A HREF="#tips.12"
><strong>iptables: What They Are and What They Do</strong></a>
<li><A HREF="#tips.13"
><strong>Code folding in Vim</strong></a>
<li><A HREF="#tips.14"
><strong>Debian "Woody" boot error</strong></a>
<li><A HREF="#tips.15"
><strong>Proxying with MAC address</strong></a>
<li><A HREF="#tips.16"
><strong>fwd: Re: [TAG] wrestling with postfix...</strong></a>
<!-- 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">Two Sound Cards Under Linux</FONT></H3>
Tue, 14 Jan 2003 03:02:07 -0500
<BR>N4FWD - Tom Kocourek (<a href="mailto:linux-questions-only@ssc.com?cc=tko@atempest.net&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%231">tko from atempest.net</a>)
<h4 align="center"><br> The Need
</h4>
<P>
As an Amateur Radio Operator, I wanted to use "QSSTV" under Linux. This program uses the DSP in a sound card to decode pictures being transmitted on Amateur Radio. However, I did not wish to give up the basic sound ability available under <A HREF="http://www.kde.org/">KDE</A>. Thus I started reading about dual sound cards.
</P>
<h4 align="center"><br>Research
</h4>
<P>
Searches via Google did not turn up much information on dual sound cards, just the usual "HOW TO" references on getting one sound card running. But, one key piece of information did turn up, that multiple sound drivers can coexist!
</P>
<h4 align="center"><br>Some experimentation and...
</h4>
<P>
Multiple sound cards can work together provided:
</P>
<blockQuote><ol>
<LI>Each additional sound card must be a different chip set (ie. different drivers)
<LI>Each sound card must have its own IRQ and distinct control register address space
</ol></blockQuote>
<h4 align="center"><br>Installation checkup
</h4>
<P>
At this point, you have physically installed the additional sound card and have verified that the BIOS has assigned different IRQs to the cards.
</P>
<P>
Now you have booted Linux and have logged in. In Mandrake Linux there is an integrated program called the MCC (or Mandrake Control Center). You can either use MCC or you can execute in a term window:
</P>
<blockquote><pre> $ /sbin/lsmod | less
</pre></blockquote>
<P>
You are verifying that different drivers have been assigned to each Sound Card. If you are not using one of the more recent distributions of Linux (such as <A HREF="http://www.redhat.com/">Red Hat</A>, Mandrake, or <A HREF="http://www.suse.com/">SuSE</A>), you may have to alter the configuration files by hand to achieve the necessary loading of the proper Sound Card drivers.
</P>
<P>
Next, you run a mixer setting program, like KMIX. If all is ok, the program should display 2 distinct mixers. If not, then you need to recheck the configuration files.
</P>
<h4 align="center"><br>Now for the tough part...
</h4>
<P>
Many sound programs are not well written. That is to say that the program assumes that only one sound card exist in your system. These types of sloppy programs will lock up Linux and require using the reset button
</P>
<P>
Well written programs allow you to set which sound card is to be used. XMMS is a well written program. While it assumes that sound card 0 is the only sound card in the system, It does not lock down Linux. QSSTV is an even better written program in that it allows you to configure which sound card is to be accessed.
</P>
<P>
"ARTSD" is a poorly written program and MUST be disabled when you run dual sound cards in your system. Otherwise, you will be reaching for the reset button!
</P>
<h4 align="center"><br>Lastly...
</h4>
<P>
I am able to play my music via XMMS and Sound Card 0; while QSSTV decodes pictures using Sound Card 1 simultaneously under Linux!
</P>
<!-- 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">rpm in debian ?</FONT></H3>
Tue, 7 Jan 2003 14:17:47 +0530
<BR>Kapil Hari Paranjape (<a href="mailto:linux-questions-only@ssc.com?cc=joy12@vsnl.net&cc=kapil@imsc.res.in&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%232%20%20rpm in debian">kapil from imsc.res.in</a>)
<BR>Question by Joydeep Bakshi (joy12 from vsnl.net)
<P><STRONG>
Hi,
I am a <A HREF="http://www.debian.org/">Debian</A> user and interested to install the rpm packages ( from RH or
MDK cds ) in Debian. but is it possible to do so ? if yse , how ?
</STRONG></P>
<BLOCKQUOTE>
[Kapil]
A debian package:
</BLOCKQUOTE>
<blockquote><pre>Package: alien
Section: admin
Architecture: all
Description: install non-native packages with dpkg
Alien allows you to convert LSB, Red Hat, Stampede and Slackware Packages
into Debian packages, which can be installed with dpkg.
.
It can also generate packages of any of the other formats.
.
This is a tool only suitable for binary packages.
</pre></blockquote>
<BLOCKQUOTE>
This suggests that "apt install alien" would do the trick for you.
</BLOCKQUOTE>
<BLOCKQUOTE>
This works as follows. You run
</BLOCKQUOTE>
<blockquote><pre> fakeroot alien -r &lt;RPM&gt;
</pre></blockquote>
<BLOCKQUOTE>
This produces a .deb which can be installed.
</BLOCKQUOTE>
<BLOCKQUOTE>
It is a good idea to read the documentation first. In particular,
please heed the warning about <EM>not</EM> installing any critical packages
this way. IF (and this is a big if) some mission critical package you
absolutely must have is <EM>not</EM> in Debian (stable or testing or
unstable), then it is generally better to run "debmake" on the
unpacked source tree to build the relevant debian package.
(of course to do this you should generally have installed
"build-essential").
</BLOCKQUOTE>
<BLOCKQUOTE>
[JimD]
</BLOCKQUOTE>
<BLOCKQUOTE><BLOCKQUOTE><CODE>
... and created a debian/rules file (a makefile starting with
<BR>#!/usr/bin/make -f).
</CODE></BLOCKQUOTE></BLOCKQUOTE>
<BLOCKQUOTE>
[Kapil]
The "alien" package is largely for (boo-hiss) non-free stuff that is
only available as binaries packaged as RPMs.
</BLOCKQUOTE>
<BLOCKQUOTE>
[JimD]
It is also possible to install the debian rpm package. You can
then directly use RPM commands. However, there won't be any
dependency database (dbm files) so all dependency checks will fail.
</BLOCKQUOTE>
<BLOCKQUOTE>
At some point someone may come with with a very clever (and probably
difficult to maintain) adapter that will generate a reasonable RPM/DBM
database set from a Debian <TT>/var/lib/dpkg/info</TT> tree. Alas that is not
in the cards for now.
</BLOCKQUOTE>
<BLOCKQUOTE>
'alien' is probably the best way to go in most cases.
</BLOCKQUOTE>
<HR width="10%" align="center"><P><STRONG>
Thanks a lot for ur valuable hints. alien is excellent. but *alien -i*
command didn't check any dependency when I installed open office (making .deb
from Mandrake cd ), hence it could not be started due to missing libraries.
</STRONG></P>
<BLOCKQUOTE>
[Kapil]
Dependencies are certainly a problem for alien. The way I understand
it, <EM>if</EM> you have the correct libraries installed then the
dependencies are included in the .deb package produced by
"alien". Otherwise "alien" only produces error messages about unmet
dependencies...
</BLOCKQUOTE>
<BLOCKQUOTE>
... a bit of a catch 22 alright!
</BLOCKQUOTE>
<BLOCKQUOTE>
But if you create the .deb files and install them in the "correct"
order (and assuming that there are no cross dependencies!) the
<EM>binary</EM> dependencies should work out correctly. What "alien" does (I'm
guessing here) is it runs "ldd" on the executables and looks for the
package that supplied the relevant library. This is how it is often done
during .deb creation.
</BLOCKQUOTE>
<BLOCKQUOTE>
Non-binary dependencies are probably unresolvable unless you can lay
your hands on an LSB package---whatever that is.
</BLOCKQUOTE>
<blockquote><font color="#000066">The Linux Standards Base is an industry-wide effort to make life easier
for companies that want to produce commercial shrinkwrap products. If
they adhere to the filesystem layout and principles described there,
then the package should be able to be installed on any Linux distro
which also claims to be LSB compliant.
</font></blockquote>
<blockquote><font color="#000066">The installers haven't quite perfected this as far as to handle
everybody's slight differences in initscript setup, but other than that
it's not too bad. At the very least a knowledgeable system admin has no
problem grafting such applications into the company-wide server.
-- Heather</font></blockquote>
<P><STRONG>
1) is it possible to let the kpackage to handle this type of converted .deb
packages and their dependency ?
</STRONG></P>
<BLOCKQUOTE>
[Kapil]
I don't know anything about kpackage but I would guess that if the
information is not in the .deb file there is not much kpackage can do.
</BLOCKQUOTE>
<P><STRONG>
2) if I have a particular directory to store all these converted .deb
packages then how to modify kpackage to display those packages in its tree
view ? ( if it is possible at all )
</STRONG></P>
<BLOCKQUOTE>
[Kapil]
There <EM>are</EM> some debian packages that allow you to create your private
repositories - there is a sledge-hammer called "apt-move" but there may
be something simpler for your requirement.
</BLOCKQUOTE>
<blockquote><font color="#000066">When the deb file is installed, if it has no section it will be placed
in the "Obsolete and Locally Created Packages" section under aptitude.
I assume kpackage has a similar feature, although I've been a bit shy of
the X-windows based apt front-ends, since I prefer to have a minimum of
processes running when updating my systems.
-- Heather</font></blockquote>
<P><STRONG>
once again thanks 4 ur solution.
</STRONG></P>
<BLOCKQUOTE>
[Kapil]
As far as openoffice and other such packages are concerned your best
bet is the "unofficial apt repositories" (which I forgot to mention in
my list of stable/testing/unstable). You can find these unofficial
repositories at:
</BLOCKQUOTE>
<BLOCKQUOTE><BLOCKQuote>
<A HREF="http://www.apt-get.org"
>http://www.apt-get.org</A>
</BLOCKQuote></BLOCKQUOTE>
<BLOCKQUOTE>
I seem to remember that this site lists a site for openoffice.
You can add that site to the list in <TT>/etc/apt/sources.list</TT>
and you should be able to then use apt-get (or probably kpackage) to
install openoffice with dependencies resolved.
</BLOCKQUOTE>
<BLOCKQUOTE>
Be warned that the unofficial repositories are un-signed packages and
could contain trojans and other such!
</BLOCKQUOTE>
<P><STRONG>
Thanks 4 all ur technical info.
</STRONG></P>
<P><STRONG>
best regards
</STRONG></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">propagating ownership and permissions</FONT></H3>
Mon, 30 Dec 2002 08:30:09 -0500
<BR>Ben Okopnik (<a href="mailto:linux-questions-only@ssc.com?cc=ben@callahans.org&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%233%20%20ownership">the <em>LG</em> Answer Gang</a>)
<P>
A while back, I wrote a utility that propagates ownership and
permissions from a sample file to a group of files. Imagine a situation
where you have, say, several dozen documents with a scattershot list of
permissions and owners/groups (since they were created by different
people.) The way to "bring them into line" would be to pick a file that
already has The Right Stuff - it doesn't even have to be in the same
directory - and say:
</P>
<blockquote><pre>cpmod /path/to/example/file *
</pre></blockquote>
<P>
Note that this utility is self-documenting. Its internal "man page" can
be read (as long as "cpmod" is somewhere in your path) with
</P>
<blockquote><pre>perldoc cpmod
</pre></blockquote>
<P>
If you want an actual man page, one can be easily created with
</P>
<blockquote><pre>pod2man cpmod|gzip -c&gt;cpmod.1.gz
</pre></blockquote>
<P>
Put the resulting file somewhere in your man directory structure
(<TT>/usr/share/man/man1</TT>, perhaps).
</P>
<p align="center">See attached <tt><a href="misc/tips/cpmod.pl.txt">cpmod.pl.txt</a></tt></p>
<BLOCKQUOTE>
[JimD]
In newer GNU utils you can use something like:
</BLOCKQUOTE>
<blockquote><pre> #!/bin/sh
reference="$1"; shift
for i in "$@"; do
chown --reference="$reference" "$i"
chmod --reference="$reference" "$i"
done
</pre></blockquote>
<P><STRONG>
[Ben]
Very cool, Jim! I hadn't seen that one before; I was only familiar with
the older versions.
</STRONG></P>
<BLOCKQUOTE>
[JimD]
(Technically I think you can just make that for i; do ...
since I think that for loops default to being in "$@" if you
don't specify an explicit list. I know they default, but I'm
not sure if they default to $* or "$@" --- if you care about the
distinction; as usual the subtleties of soft-quoting are there to
protect degenerate filenames containin whitespace!).
</BLOCKQUOTE>
<BLOCKQUOTE>
In other GNU utils you can use a little trickery like:
</BLOCKQUOTE>
<blockquote><pre> #!/bin/sh
reference="$1"; shift
UID=$(find "$1" -maxdepth 0 -printf "%U" )
MODE=$(find "$1" -maxdepth 0 -printf "%m" )
for i in "$@"; do
chown "$UID" "$i"
chmod "$MODE" "$i"
done
</pre></blockquote>
<BLOCKQUOTE>
Ben, am I missing some subtleties here? (Other than the obviously
argument counting, error checking and messages, and some getopts to
provide --help, --owner-only, --mode-only etc.)
</BLOCKQUOTE>
<P><STRONG>
[Ben]
Not so far as I can see. However, the Perl version is shorter (if you
ignore the included man page.)
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle">
</STRONG></P>
<!-- 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">boot to windows by default</FONT></H3>
9 Jan 2003 05:16:50 -0000
<BR>David Mandala, Jim Dennis (<a href="mailto:linux-questions-only@ssc.com?cc=anuragsahay@rediffmail.com&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%234">the <em>LG</em> Answer Gang</a>)
<BR>Question by anurag sahay (anuragsahay from rediffmail.com)
<P><STRONG>
Hi Answer guy,
I ahve two questions
</STRONG></P>
<P><STRONG>
1.
I have linux and Windows both loaded on my system.i wanted to
boot to windows by default.how can i chang the lilo.conf
file.what are the changes to be made there.
</STRONG></P>
<BLOCKQUOTE>
[David]
The answer to your question about lilo is to edit the <TT>/etc/lilo.conf</TT>
file.
</BLOCKQUOTE>
<BLOCKQUOTE>
Your file might look something like this:
</BLOCKQUOTE>
<p align="center">See attached <tt><a href="misc/tips/linux-and-dos.lilo-conf.txt">linux-and-dos.lilo-conf.txt</a></tt></p>
<BLOCKQUOTE>
Cheers,
Davidm
</BLOCKQUOTE>
<BLOCKQUOTE>
[JimD]
Essentially, add a default= directive to your <TT>/etc/lilo.conf</TT>
(or edit your <TT>/boot/menu.lst</TT> file if you're using GRUB).
Read the lilo.conf man (and/or GRUB info) pages for more detail on
that.
</BLOCKQUOTE>
<BLOCKQUOTE>
The Linux Documentation Project (<A HREF="http://www.tldp.org"
>http://www.tldp.org</A> ) has an
entire section of HOWTOs on boot loaders and related topics (about
a dozen of them):
</BLOCKQUOTE>
<BLOCKQUOTE><BLOCKQuote>
<A HREF="http://www.tldp.org/HOWTO/HOWTO-INDEX/os.html#OSBOOT"
>http://www.tldp.org/HOWTO/HOWTO-INDEX/os.html#OSBOOT</A>
</BLOCKQuote></BLOCKQUOTE>
<!-- 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">network programming - accepting data</FONT></H3>
9 Jan 2003 05:16:50 -0000
<BR>Kapil Hari Paranjape, Jim Dennis (<a href="mailto:linux-questions-only@ssc.com?cc=anuragsahay@rediffmail.com&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%235">the <em>LG</em> Answer Gang</a>)
<BR>Question by anurag sahay (anuragsahay from rediffmail.com)
<P><STRONG>
Hi Answer guy,
I ahve two questions
</STRONG></P>
<P><STRONG>
2.
This about unix network programming: How to accept any data
from any given port.
</STRONG></P>
<P><STRONG>
thanking you
<BR>yours anurag
</STRONG></P>
<BLOCKQUOTE>
[Kapil]
Have a look at the utlities "netcat" and "socat".
</BLOCKQUOTE>
<BLOCKQUOTE>
[JimD]
You could use netcat (often named <TT>/usr/bin/nc</TT>) or socat
directly (from shell scripts, etc) to listen on arbitrary TCP or UDP
ports. Note: the process has to have 'root' privileges to listen on
"privileged" ports -- those from 1 to 1023 inclusive (or maybe it's
1024 inclusive --- I never remember that one).
</BLOCKQUOTE>
<BLOCKQUOTE>
More to the point, you can read the source code to netcat or socat
(included with most distributions on the "Source Code" disc or
readily downloadable from many archive sites on the net. As a <A HREF="http://www.debian.org/">Debian</A>
user I find it most convenient to get most sources with a simple
'apt-get source' command. Debian tracks, index, and automatically
fetches, unpacks and patches the sources for me. With an 'apt-get
build-dep' command I can also have Debian fetch and install all of
the packages that are required to build almost any other package from
its sources (they're still working on that feature).
</BLOCKQUOTE>
<BLOCKQUOTE>
It makes me reluctant to hunt down the upstream sources, suitable
for other distros and other forms of UNIX.
</BLOCKQUOTE>
<BLOCKQUOTE>
These things change far too frequently, but Google is our friend.
It appears that the current canonical location for finding Hobbit's
netcat sources is at:
</BLOCKQUOTE>
<BLOCKQUOTE><BLOCKQuote>
<A HREF="http://www.atstake.com/research/tools/network_utilities"
>http://www.atstake.com/research/tools/network_utilities</A>
</BLOCKQuote></BLOCKQUOTE>
<BLOCKQUOTE>
... where he (Hobbit) seems to have an e-mail address. Perhaps he
works at @Stake.
</BLOCKQUOTE>
<BLOCKQUOTE>
As for socat its author, Gerhard Rieger, conveniently list the package's
home page in the man page that comes with the package (at least with the
Debian package): <A HREF="http://www.dest-unreach.org/socat"
>http://www.dest-unreach.org/socat</A>
</BLOCKQUOTE>
<BLOCKQUOTE>
Reading the sources to these will teach you alot about UNIX network
programming. In particular netcat has been around for a very long
time and has had VERY FEW bugs reported against it. It's been
scrutinized by thousands, probably tens of thousands of programmers.
</BLOCKQUOTE>
<BLOCKQUOTE>
You should also buy Richard Stevens' seminal textbook on
<EM>UNIX</EM> <EM>Network</EM> <EM>Programming</EM> (Prentice Hall). Read more about that at:
</BLOCKQUOTE>
<BLOCKQUOTE><BLOCKQuote>
<A HREF="http://www.kohala.com/start"
>http://www.kohala.com/start</A>
</BLOCKQuote></BLOCKQUOTE>
<!-- end 5 -->
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<P> <A NAME="tips.6"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Key bindings in X</FONT></H3>
Wed, 22 Jan 2003 07:51:49 +0800
<BR>jamie sims (<a href="mailto:linux-questions-only@ssc.com?cc=jaymz@operamail.com&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%236">jaymz from operamail.com</a>)
<P>
Here's the fix I finally hit upon to get those F keys working
in xterm. I edited a copy of <TT>/usr/X11R6/lib/X11/app-defaults/XTerm</TT> and added the
following:
</P>
<P><BLOCKQuote>
See attached
<a href="misc/tips/XTerm.app-defaults.txt">XTerm.app-defaults.txt</a>
</BLOCKQuote></P>
<P>
I then saved it as .Xdefaults and it works very well.
</P>
<blockquote><font color="#000066">You can use the .Xdefaults file in your home directory to add or
override X internal resources for any application - so make sure that
if you already have some features stored there, that you add this
into it, instead of replacing it.
-- 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">alsa in debian</FONT></H3>
Sun, 19 Jan 2003 12:52:21 +0530
<BR>Kapil Hari Paranjape (<a href="mailto:linux-questions-only@ssc.com?cc=joy12@vsnl.net&cc=kapil@imsc.res.in&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%237">kapil from imsc.res.in</a>)
<BR>Question by Joydeep Bakshi (joy12 from vsnl.net)
<P><STRONG>
Hi there,
u know alsa in not built in debian 3.0 by default. but alsa utils... &amp; driver
&amp; header files are present in the 7cd set. could any one please tell me how
to build the alsa modules in debian &amp; the required packages 4 this ?
</STRONG></P>
<P><STRONG>
Note: there are some alsa-modules ( in the cds ) based on 2.4.16 kernel, but
mine is 2.4.18
</STRONG></P>
<P>
Where you got the kernel-image-2.4.18 you should also find the
relevant alsa-modules-2.4.18. Anyway here is the procedure to build
alsa modules for debian.
</P>
<P>
1. Use apt-get to install the relevant alsa-source package. You could
also download the sources from the alsa ftp site --- I haven't tried
that but it should work.
</P>
<P>
2. Install the relevant kernel source package, and the package
kernel-package.
</P>
<P>
3. Unpack the kernel source and alsa-modules in <TT>/usr/src.</TT>
</P>
<P>
4. Run "make-kpkg --config=menuconfig" configure in the kernel source
directory.
</P>
<P>
5. Run make-kpkg kernel-image and make-kpkg modules-image.
</P>
<P>
6. This should build a pair of compatible kernel-image and
alsa-modules package files which you can install with dpkg.
</P>
<P>
7. Of course you need to edit your grub menu or lilo conf file and so
on to run this kernel.
</P>
<P>
8. You can then configure alsa with alsa-conf alsa-base and so on.
</P>
<P>
Remember to set and save the mixer settings so that
<TT>/etc/init.d/alsa</TT> script (which is part of alsa-base) can restore
these settings.
</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">pppd</FONT></H3>
Fri, 3 Jan 2003 11:24:26 -0800
<BR>Mike Iron Orr, Ben Okopnik (<a href="mailto:linux-questions-only@ssc.com?cc=joy12@vsnl.net&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%238">the <em>LG</em> Answer Gang</a>)
<BR>Question by Joydeep Bakshi (joy12 from vsnl.net)
<P><STRONG>
pppd command shows a few strings character in RH, but in debian it shows
error
</STRONG></P>
<P><STRONG>
" remote system needs to authenticate itself" &amp; discontinue
</STRONG></P>
<BLOCKQUOTE>
[Ben]
Ah, I'd missed this part. Neil is right - you don't have the "noauth"
option defined in your "<TT>/etc/ppp/peers/provider</TT>" or whatever options
file you're using.
</BLOCKQUOTE>
<BLOCKQUOTE>
[Iron]
I haven't used ppp for years (but I will soon, when I set up my mom's computer),
but yes, if you're dialing into an ISP you want "noauth". Otherwise your Linux
box will require authentication from the server, which it won't do. The server
thinks *it's* trusted and *you're* the one who has to authenticate yourself.
And even if it was willing to authenticate itself, how could it? It doesn't
have a password to authenticate itself <EM>with</EM>. The (nonexistent) password the
servers would authenticate themselves with is different than the user password
you authenticate yourself with.
</BLOCKQUOTE>
<BLOCKQUOTE>
If people are dialing <EM>into</EM> your Linux system, then you want authorization
<EM>for those calls</EM>.
</BLOCKQUOTE>
<P><STRONG>
Thanks 4 the solution,
it is working now.
</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">Is that your FIN_WAIT Answer?</FONT></H3>
Mon, 13 Jan 2003 19:00:25 -0800
<BR>Jim Dennis (<a href="mailto:linux-questions-only@ssc.com?cc=linux-questions-only@ssc.com,&cc=jimd@starshine.org&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%239">the <em>LG</em> Answer Guy</a>)
<!-- ::
Is that your FIN_WAIT Answer?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:: -->
<P><STRONG>
I am using RedHat Advanced Server 2.1, Kernel 2.4.9 and am having the
following problem:
</STRONG></P>
<P><STRONG><BLOCKQuote>
If I log on as userA via a telnet session and run Test_pgm and then
disconnect the telnet session by closing the window instead of properly
logging out, this is what is shown from the ps command:
</BLOCKQuote></STRONG></P>
<pre><strong>UID PID PPID C STIME TTY TIME CMD
userA 8505 1 0 14:00 ? 00:00:00 login -- userA
userA 8506 8505 0 14:00 ? 00:00:00 -bash
userA 8540 8506 87 14:00 ? 00:00:42 Test_pgm
</strong></pre>
<P><STRONG>
Notice that there is no longer a TTY associated with the running program or
the original login and the PPID of the login has been inherited by process
ID#1. Furthermore, if I do a top command, the results show that the CPU Idle
% is zero, with the Test_pgm using up all of the CPU %. The load average
goes through the roof. I've seen it up close to 30.0. However, the system's
performance does not seem to be effected by me or by any of the users. These
processes are not listed as zombies and are never cleaned up by the system
unless I kill the login process or restart the server.
</STRONG></P>
<BLOCKQUOTE>
Most of this seems normal (for a program that's ignoring SIGHUP). The
loadavg number seems odd.
</BLOCKQUOTE>
<P><STRONG>
This scenario happens whether the user is running an in-house 'C' program or
an operating system utility such as Redhat's setup. Within our own 'C'
programs, I have tried to capture a terminating signal, using the <TT> signal()</TT>
command, but I am not seeing any of the signals
that I would expect to see, such a SIGTERM or SIGHUP.
</STRONG></P>
<P><STRONG>
Does anyone have any ideas as to how to tell RedHat to take down the
processes associated with a telnet when a tty disappears?
</STRONG></P>
<P><STRONG>
Thanks in advance.
<BR>DP
</STRONG></P>
<BLOCKQUOTE>
in.telnetd should be sending a SIGHUP to the process when the TCP
connection is closed (including when the keepalive fails?).
</BLOCKQUOTE>
<BLOCKQUOTE>
Run 'netstat -na' and see if the TCP connection is lingering in
FIN_WAIT state. This could be a case where your (probably MS-Windows)
telnet client is failing to properly perform the three-way
disconnection handshaking that's required of TCP. (I recall problems
with some MS Windows FTP clients resulting in similar symptoms on
high volume public FTP servers).
</BLOCKQUOTE>
<BLOCKQUOTE>
Try it with a UNIX telnet client.
</BLOCKQUOTE>
<BLOCKQUOTE>
Try it with ssh.
</BLOCKQUOTE>
<BLOCKQUOTE>
If it works with ssh, perhaps you can use that as leverage with your
users and management to abandon this insecure and deprecated protocol!
(PUTTY is a very good, and free, ssh client for MS Windows operating
systems. There are many others).
</BLOCKQUOTE>
<BLOCKQUOTE>
Other than that, I would try upgrading the kernel (2.4.9 was pretty
miserable under memory load) and watch one of these sessions with tcpdump
and strace (so you can correlate what's happening on the wire with
what's happening in the process). Upgrading to RH 7.3 might also be
good since the compilers and libraries in 7.1 and 7.2 had ... issues.
</BLOCKQUOTE>
<BLOCKQUOTE>
Without knowing more about what Test_pgm is supposed to do, I can't
immediately suggest any other workarounds.
</BLOCKQUOTE>
<!-- 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">direct rendering for nvidia RIVA 128</FONT></H3>
Sun, 19 Jan 2003 00:13:51 +0100
<BR>Yann Vernier (<a href="mailto:linux-questions-only@ssc.com?cc=rscottf@ieee.org&cc=yann@algonet.se&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%2310">yann from algonet.se</a>)
<BR>Question by linux-questions-only@ssc.com, Scott Frazier (rscottf from ieee.org)
<P><STRONG>
I have a nvidia velocity 128 video card, which uses the RIVA 128
accelerator chip. I'm running Mandrake 9.0, which sets it up with
glx (3D capability), but with no direct rendering (uses software
rendering). Needless to say this REALLY slows it down for games.
Does anyone know how I might resolve this?
I've tried changing an entry in the XF86Config file, in the
MODULES section. I added the line Load "dri", to no avail.
I'm pretty sure the card is dri capable, as it is able to do bus
mastering, which is a must for this.
</STRONG></P>
<P>
Sorry to disappoint you, but last time I checked there was no DRI driver
for the Riva 128. It's among the earliest nVidia chips, and nVidia's own
binary-only driver only supports TNT or later (two models newer). There
was a partly accelerated Mesa-based GLX implementation for XFree86 3
that supported it, however, called Utah-GLX. You may be able to run
that, but you'd obviously lose out on all other new features of XFree86
4.
</P>
<!-- end 10 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="tips.11"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">xcdroast post cdrom mount problem</FONT></H3>
Fri, 10 Jan 2003 17:32:51 -0500
<BR> (<a href="mailto:linux-questions-only@ssc.com?cc=bbertsch@surfside.net&cc=&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%2311"></a>)
<BR>Question by Brian (bbertsch from surfside.net)
<P><STRONG>
hello,
i'm a recovering os/2 user. i used it today, and i may have to
tomorrow... but i can stop any time i want to.. but my modem....
</STRONG></P>
<P><STRONG>
Anyway, after i use xcdroast, (which i am getting used to, under RH8-<A HREF="http://www.kde.org/">KDE</A>)
i am unable to check the cdrom just made because the cdrom will not
mount. (ide double cheapo brand 48x, works great). i have to use the
newly-made cd on my os/2 machine to check it. my friends laugh at me.
</STRONG></P>
<P><STRONG>
thanks, brian
</STRONG></P>
<BLOCKQUOTE>
[JimD]
You probably need to change <TT>/dev/cdrom</TT> to be a symlink to <TT>/dev/scd0</TT> or
something like that.
</BLOCKQUOTE>
<BLOCKQUOTE>
Linux normally handles your ATAPI CD-R drive via a SCSI emulation
layer. Once this layer is active (possibly via a loadable module)
then all access to the CD has to go through the SCSI device nodes
(<TT>/dev/sg*</TT> for writing, and <TT>/dev/scd0</TT> for mounting CDs).
</BLOCKQUOTE>
<BLOCKQUOTE>
Try that. Try this command first:
</BLOCKQUOTE>
<BLOCKQUOTE><BLOCKQUOTE><CODE>
mount -t iso9660 -o ro /dev/scd0 /mnt/cdrom
</CODE></BLOCKQUOTE></BLOCKQUOTE>
<BLOCKQUOTE>
... from a root shell prompt.
</BLOCKQUOTE>
<BLOCKQUOTE>
[John]
Greetings from another former OS/2 user - although I used it for about 2
yrs or so, and switched to Linux.
</BLOCKQUOTE>
<BLOCKQUOTE>
Anyway, have you read CD's made from that cooker before? Could be a
hardware issue. Some of those really cheap devices lack some features.
But chances of that would seem a bit slim if it's a 48X drive, cuz those
compatibility problems are usually more common with the older drives. But
I wouldn't rule it out as a possibility.
</BLOCKQUOTE>
<!-- 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">iptables: What They Are and What They Do</FONT></H3>
Tue, 7 Jan 2003 04:18:33 -0800
<BR>Jim Dennis (<a href="mailto:linux-questions-only@ssc.com?cc=collin_sq2003@yahoo.com&cc=jimd@starshine.org&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%2312">the <em>LG</em> Answer Guy</a>)
<BR>Question by peter collins (collin_sq2003 from yahoo.com)
<P><STRONG>
could you please explain to me what iptables are and what they do
</STRONG></P>
<P>
IPTables are tables (lists) of packet filtering rules in the Linux
kernel. They are added (passed into the kernel's address space)
and manipulated using a command named: 'iptables' and they are
interpreted by various kernel modules written to the "netfilter"
APIs (primarily by Paul "Rusty" Russell).
</P>
<P>
Each rule is a pattern matching some sorts of network traffic
based on many criteria (IP source or destination addresses,
TCP or UDP source and destination ports, ICMP type, IP or other
options (flags), connection status (correlated from other, previous
packets), even MAC addresses, which interface and direction they're
coming from or destined to, which local processes are generating
them, etc.). Part of each rule is a "disposition" like: DROP, REJECT,
ACCEPT, "jump" to another ruleset (table) etc.
</P>
<P>
The ability to conditionally process different packets in various ways,
and even to conditionally "call" on some rulesets, makes iptables into
a very specialized programming language. IPChains was somewhat
different, simpler packet filtering language (also by Rusty), and
ipfwadm was a much simpler packet filtering system back in the 2.0
kernel days.
</P>
<P>
It looks like the 2.6 kernel, probably due out sometime this year, will
be the first one since 1.3 that hasn't had a major overhaul in the
packet filtering language. IP Tables was released with 2.4 and has
only undergone minor bug fixes and refinement since then.
</P>
<P>
Note that most of the packet filtering rules relate to whether to
allow a packet through the system, to DROP it (with no notice)
or REJECT it (providing an ICMP or error back to its sender, as
appropriate), MASQUERADE or TRANSLATE it (change its apparent source
address and port (usually setting up some local state to dynamically
capture and re-write any response traffic related to it), REDIRECT it
(change its destination address and/or port), change its "ToS" (type
of service) bits. It's also possible to attach an FWMARK to a packet
which can be used by some other parts of the Linux TCP/IP subsystem.
</P>
<P>
What IPTables is NOT:
</P>
<P><BLOCKQuote>
There is another subsystem, similarly complex and seemingly related
--- but distinct from netfilter (the kernel code that support IP
Tables). This is the "policy routing" code --- which is controlled
with the tersely named 'ip' command (the core of the iproute2 package).
</BLOCKQuote></P>
<P>
Policy routing is different that packet filtering. Where packet
filters is about whether the packets go through, and whether some parts
of a packet are re-written, policy routing is purely about <EM>how</EM> they
are sent towards their destination. Under normal routing every
outbound and forwarded packet is sent to its next hop based exclusively
on its destination address. Under policy routing it's possible to send
some traffic through one router based on its source address, port or
protocol characteristic, etc. This is different than the IP tables
"REDIRECT" because this doesn't change the packet --- it just sends it
to a different router based on the policy rules.
</P>
<P>
The two subsystems can interact, however. For example policy routing
does include options to match on the ToS or FWMARK that might be attached
to a packet by the iptables rules. (These FWMARKs are just identifiers
that are kept in the kernel's internal data structure about the packet
--- they never leave the system and can't go over the wire with the
packet. ToS are only a couple of bits in the header, hints that
traditionally distinguish between "expedited" (telnet) and "buld" (ftp)
traffic).
</P>
<P>
The iproute2 package and the 'ip' command replace the ifconfig command
and provide considerable control over interfaces. It also allows one
to set "queueing disciplines" to interfaces which determine which
packets get to "go first" when there are more than one of them waiting
to be sent over given interface.
</P>
<P>
There is alot more I could tell you about Linux routing and network
support. For example none of this relates to dynamic routing table
management. There are user space programs like routed, gated, and
various GNU Zebra modules, that can listening to various dynamic
routing protocols such as RIP, RIPv2, OSPF, BGP, etc. to automatically
add and remove entries to the kernel's routing tables. Some of these
might be able to also dynamically set <EM>policies</EM> as they do so.
There is also a Linux compile time option called "Equal Cost
Multi-path" which is not part of policy routing. Normally if you added
two static routes of "equal cost" than the first one (of the lowest
cost) would always be used, unless the system was getting "router
unavailable" ICMP messages from somewhere on the LAN. However, with
Equal Cost Multipath the system will distribute the load among
such routes. This can be used to balance the outbound traffic from a
very busy system (such as a popular web server or busy mail gateway) among
multiple routers (connected to multiple ISPs over multiple T1s or whatever).
</P>
<P>
(This is similar to a trick with policy routing --- assigning a couple
of IP "aliases" --- different IP addresses --- to one interface; one
from one ISP, another from a different one, and using policy routing
to ensure that all response/outbound packets <EM>from</EM> one of these sources
go through the appropriate router. DNS round robin will balance the
incoming load, and policy routing will balance the response load.
Equal Cost Multipath will balance traffic <EM>initiated</EM> from that host).
</P>
<P>
Again, all of these last paragraphs are NOT IP tables. I'm just trying
to give you a flavor of other networking stuff in Linux apart from it,
and to let you know that it, if you don't find what you need in the
iptables documentation, it might be somewhere else.
</P>
<P>
To learn more about Netfilter and IP Tables, please read though the
appropriate HOWTOs:
</P>
<P><BLOCKQuote>
<A HREF="http://www.tldp.org/LDP/nag2/x-087-2-firewall.future.html"
>http://www.tldp.org/LDP/nag2/x-087-2-firewall.future.html</A>
<A HREF="http://www.netfilter.org"
>http://www.netfilter.org</A>
</BLOCKQuote></P>
<!-- sig -->
<!-- sig -->
<!-- end 12 -->
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<P> <A NAME="tips.13"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Code folding in Vim</FONT></H3>
12 Jan 2003 23:53:53 +0530
<BR>Ashwin N (<a href="mailto:linux-questions-only@ssc.com?cc=ashwin_n@gmx.net&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%2313">ashwin_n from gmx.net</a>)
<P>
Vim versions 6.0 and later support a new feature called Code Folding.
Using code folding a block of code can be "folded" up into a single
line, thus making the overall code easier to grasp.
</P>
<P>
The Vim commands to use code folding are quite simple.
</P>
<P>
To create a fold just position the cursor at the start of the block of
code and type :
zfap
</P>
<P>
To open a fold :
zo
</P>
<P>
To close a fold :
zc
</P>
<P>
To open all the folds :
zr
</P>
<P>
To close all the folds :
zm
</P>
<P>
For more commands and information on code folding in Vim query the
inbuilt help feature of Vim :
:help folding
</P>
<BLOCKQUOTE>
[John Karns]
You're quite right. Folding is particularly useful for
long sections of code that contain loops, etc. I use
it extensively in this context.
</BLOCKQUOTE>
<BLOCKQUOTE>
Other uses include long paragraphs of prose.
</BLOCKQUOTE>
<BLOCKQUOTE>
But make sure you are in command mode! If you are in text
entry mode, just typing in "zfap" would literally embed that
string into your text!
</BLOCKQUOTE>
<blockquote><font color="#000066">If you're in text entry mode, press Escape to get back into
command mode.
</font></blockquote>
<blockquote><font color="#000066">Vi has two command modes and a text entry mode. When you come
in you are at ordinary command mode. When you type a colon
(such as what precedes the word "help" above) then you end up
with a small colon prompt. The above commands are NOT colon
mode commands, except for help. But you do need your cursor
at the right location.
</font></blockquote>
<blockquote><font color="#000066">The colon prompt is also called "ex mode" by old hands at vi,
but I'm not entirely sure that all the commands that use it
are really old commands at all. Some are surely long words
allowing you to access some enhanced features, too, because
there are only so many letters in the alphabet.
</font></blockquote>
<blockquote><font color="#000066">To get out of the help mode you may need to type :q to quit
the extra window it created. Your original textfile is still
around, don't worry.
-- Heather</font></blockquote>
<!-- 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">Debian "Woody" boot error</FONT></H3>
Tue, 21 Jan 2003 16:30:32 -0600
<BR>Robos (<a href="mailto:linux-questions-only@ssc.com?cc=rich@gandalf.ws&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%2314">the <em>LG</em> Answer Gang</a>)
<BR>Question by Rich Price (rich from gandalf.ws)
<P><STRONG>
After installing the Woody release of <A HREF="http://www.debian.org/">Debian</A> using the idepci kernel I
noticed the following boot message
</STRONG></P>
<pre><strong>modprobe: Can't locate module char-major-10-135
</strong></pre>
<P><STRONG>
Some Google searching led me to the following factoid:
</STRONG></P>
<P><STRONG><BLOCKQuote>
"char-major-10-135" refers to the character device, major 10, minor 135,
</BLOCKQuote></STRONG></P>
<P><STRONG>
which is <TT>/dev/rtc.</TT>
It provides access to the BIOS clock, or RTC, the Real Time Clock.
</STRONG></P>
<BLOCKQUOTE>
[Robos]
OH MY GOSH! REINSTALL!
(Just kidding)
</BLOCKQUOTE>
<blockquote><font color="#000066">This doesn't actually mean that your computer has no sense of time at
all; it just means you won't be able to access the additional precision
it has available, without extra code in the kernel. If you have SMP,
the kernel docs warn that it's important to compile this in. Otherwise,
very few things actually care.
</font></blockquote>
<blockquote><font color="#000066">But in a new enough kernel, with devfs support, any app which is
curious about it (that is, would use the extra support if you have it,
but ignore it if you don't) will provoke a complaint when the userland
devfsd attempts to autoload the module. You can tell it to ignore that
stuff, detailed in devfsd's man page.
-- Heather</font></blockquote>
<P><STRONG>
So, fine, I want it.
</STRONG></P>
<BLOCKQUOTE>
[Robos]
Hmm, ok
</BLOCKQUOTE>
<P><STRONG>
I looked around in the distro CDs, but I couldn't find the char-major-10-135
module.
No luck at the Debian site either. Where can I find a copy of this module
compiled for the
Debian Woody idepci kernel?
</STRONG></P>
<BLOCKQUOTE>
[Robos]
Actually it has to be compiled in the kernel to be either hard integrated or
to be loadable as a module. It <EM>seems</EM> as if they (the debian kernel package
maintainer) did neither. So, either you bake your own kernel and tick the
appropriate field in make xconfig or you need to look (grep) through some
configs of kernels (packaged ones) to find one which has rtc true oder m.
BTW, I have this message too on all my machines with hand made kernels and
it didn't bother me a thing till now...
</BLOCKQUOTE>
<BLOCKQUOTE>
[Iron]
char-major-10-135 is a generic name; the module itself won't be called that.
Take a look in <TT>/etc/modules.conf</TT> . The "alias" lines map the generic name to
a specific module that provides it, for instance:
</BLOCKQUOTE>
<blockquote><pre>alias char-major-10-175 agpgart
</pre></blockquote>
<BLOCKQUOTE>
In this case, some program or daemon is trying to access the real time clock.
You can also create your own aliases; e.g., I name my Ethernet cards according
to their interfaces:
</BLOCKQUOTE>
<blockquote><pre>alias eth0 3c59x
alias eth1 eepro100
</pre></blockquote>
<BLOCKQUOTE>
So when my network initialization script does:
</BLOCKQUOTE>
<blockquote><pre>modprobe eth0
modprobe eth1
</pre></blockquote>
<BLOCKQUOTE>
I know eth0 will connect to the 3C905 card (DSL) and eth1 will connect to the
EE PRO card (LAN). And if I have to change cards later, I can just change the
alias lines and leave everything else along. (The only thing I can't do is
use two cards of the same brand, because then I would have no control over their
initialization order except by seeing which PCI slot has the lowest base
address: "cat <TT>/proc/ioports</TT>". If eth0 and eth1 get reversed, the network
won't work because packets will get routed to the wrong network.)
</BLOCKQUOTE>
<BLOCKQUOTE>
Anyway, the easiest way to "fix" your problem is to add an alias:
</BLOCKQUOTE>
<blockquote><pre>alias char-major-10-175 off
</pre></blockquote>
<BLOCKQUOTE>
That tells modprobe to shut up because there is no module for that service.
So whatever is asking for that module will abort or do without. Whether that's
a problem or not depends on what the program is trying to do and whether you
need it. I have never run into problems aliasing char-major-*-* modules off.
</BLOCKQUOTE>
<BLOCKQUOTE>
Of course, the "correct" solution is to find out what's using the module and
disable it if you don't need it.
</BLOCKQUOTE>
<BLOCKQUOTE>
In my Linux 2.4.17 source, "make menuconfig", "character devices",
"Enhanced Real Time Clock support", "Help" (press Help while the cursor is
on the RTC line) says the module file is "rtc.o". You can also guess that from
the config option name at the top: CONFIG_RTC. That's the file you want from
your distribution disk. On Debian it would be in a kernel modules package.
</BLOCKQUOTE>
<BLOCKQUOTE>
Note that Debian has a configurator for <TT>/etc/modules.conf.</TT> Instead of editing
that file directly, edit <TT>/etc/modutils/aliases</TT> and then run "update-modules".
See "man 8 update-modules".
</BLOCKQUOTE>
<!-- 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">Proxying with MAC address</FONT></H3>
Sun, 12 Jan 2003 05:00:20 -0800
<BR>Jim Dennis (<a href="mailto:linux-questions-only@ssc.com?cc=gansh@rediffmail.com&cc=jimd@starshine.org&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%2315">the <em>LG</em> Answer Guy</a>)
<BR>Question by Ganesh M (gansh from rediffmail.com)
<P><STRONG>
Thanks to Karl-Heinz Herrmann for bearing with me, just one little
<BR>question please.
</STRONG></P>
<P><STRONG>
Is it possible to restrict internet access by private LAN PCs
taking into account their MAC address instead of the IP address
by any means, i.e., Masquerading/Proxying etc. Can masquerading
and proxying co-exist, and if so, what is the advantage?
</STRONG></P>
<P><STRONG>
Thanks
<BR>M Ganesh
</STRONG></P>
<P>
It should be possible (though <EM>very</EM> cumbersome) to configure your
networks so that only registered MAC addresses are routed from one
internal network to another (including via the border router to the
Internet).
</P>
<P>
Under Linux you could write scripts to do this using the MAC Address
Match option/module in the Linux kernel configuration (*) (named:
CONFIG_IP_NF_MATCH_MAC in the .config file).
</P>
<blockquote><em><font color="#000033"><br> *(Networking Options --&gt; Netfilter Configuration --&gt; IP Tables)
</font></em></blockquote>
<P>
However, it's probably an ill-advised strategy. Many people try
to limit this by setting up their DHCP servers with known MAC addresses
and refusing to give out IP addresses to unknown systems. They then
might couple this with monitoring using the 'arpwatch' package to
detect new ARP (MAC/IP address combinations) and with 'snort' to
warn them of other suspicious network activity.
</P>
<P>
As for co-existence of IP Masquerading and applications layer proxying.
Yes they can co-exist --- and are even sensible in some cases. In fact
it's common to use something <EM>like</EM> IP Masquerading with the Squid caching
web proxy --- in its "transparent proxy" configuration.
</P>
<P>
In general you might use proxies for those protocols that support it,
and for inbound connections; while letting systems fall back on IP
masquerading other work (subject to your packet filtering, of course).
</P>
<P>
The advantages of application proxy systems are largely in three
dimensions: They can be quite simple, and run in user space often as a
non-privileged process (security and simplicity); they can reflect
higher level policies because they have access to the applications and
sessions layers of the protocol that is being proxied (flexibility and
control), they may be able to provide better performance (performance,
especially via caching).
</P>
<P>
However, any particular proxy might not provide real advantages in all
(nor even ANY) of these areas. In particular the Delegate proxy system
seems to be riddled with buffer overflows, for example. Squid is a
nice caching proxy for web and some other services --- and it has some
security and policy management features and optional modules. However,
Squid configuration and administration can be quite complicated. It's
far too easy to inadvertantly make your Squid system into a free
anonymizing proxy for the whole Internet, or to make it into an
unintentional <EM>inbound</EM> proxy to your own intranet systems.
</P>
<P>
While a proxy <EM>might</EM> have access to the application/session layer data
(in the payloads of the IP packets) --- it might not have a reasonable
means for expressing your policies regarding acceptable use of these
protocols.
</P>
<P>
Also there are always those new protocols for which no proxies have
been written. There will frequently be considerable demand by your
users and their management to provide access to the latest and greatest
new toys on the Internet (Pointcast was an historic example, Internet
radio is, perhaps, a more recent one).
</P>
<P>
These issues are very complex, and I can't do them justice at 5am after
staying up all night
<IMG SRC="../gx/dennis/smily.gif" ALT=";)"
height="24" width="20" align="middle">
</P>
<!-- 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">fwd: Re: [TAG] wrestling with postfix...</FONT></H3>
Sun, 19 Jan 2003 09:01:44 -0800
<BR>Dan Wilder (<a href="mailto:linux-questions-only@ssc.com?cc=rnegut@yahoo.com&subject=%20Re%3A%20%5BLG%2087%5D%202c%20Tips%20%2316">the <em>LG</em> Answer Gang</a>)
<BR>Question by Radu Negut (rnegut from yahoo.com)
<P><STRONG>
Hi!
After going twice through the postfix documentation, I
still couldn't figure it out if it is possible to
configure mail for groups (e.g.
<A HREF="mailto:sales_managers@domain.com"
>sales_managers@domain.com</A>) otherwise besides aliasing
all group members to that address in
<TT>/etc/postfix/aliases.</TT> Does postfix reread the aliases
as well if 'postfix reload' is issued or only the .cf
file? Does 'service postfix restart' reset all
mailques, resulting in dropped/lost mail? I've looked
</STRONG></P>
<P>
For alias lists, add stuff to <TT>/etc/aliases</TT> then run
</P>
<P><CODE>
postalias /etc/aliases
</CODE></P>
<P>
If you don't care whether the new aliases are effective instantly,
you're done. Very shortly Postfix will notice
the aliases file is updated and will reload it.
</P>
<P>
You may keep aliases in additional files. See the
</P>
<P>
alias_maps =
</P>
<P>
parameter in main.cf. You can add as many alias files as you
like.
</P>
<P>
For bigger lists, or frequently changing ones, investigate
mailing list software. I use Mailman or majordomo myself.
See the URL below.
</P>
<P><STRONG>
around but couldn't find if postfix can be configured
to use accounts other than from <TT>/etc/passwd</TT> (and I'm
not talking about aliases). What I mean is normal mail
spools, but for users that get specified in a separate
file and who do not have any permissions on the system
whatsoever.
</STRONG></P>
<P>
Briefly, you can't do normal UNIX mail delivery except to users
from <TT>/etc/passwd.</TT> However you <EM>can</EM> do POP3/IMAP delivery
to a software that maintains its own list of users. You're looking
for something like Cyrus. You'll find it under the POP3/IMAP servers
section of
</P>
<P>
<A HREF="http://www.postfix.org/addon.html"
>http://www.postfix.org/addon.html</A>
</P>
<P>
Take the time to browse the other pages of the postfix.org site.
</P>
<P>
--
Dan Wilder
</P>
<!-- sig -->
<!-- end 16 -->
<!-- *** 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; 2003
<br>Copying license <A HREF="http://www.linuxgazette.com/copying.html">http://www.linuxgazette.com/copying.html</A>
<BR>Published in Issue 87 of <i>Linux Gazette</i>, February 2003</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"
WIDTH="200" HEIGHT="41" border="0"></A>
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD>
<center>
<img src="../gx/dennis/qbubble.gif" alt="(?)"
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>
</TABLE>
<P>
<!-- END header -->
<center><p>
<br>We have guidelines for <a href="http://www.linuxgazette.com/tag/ask-the-gang.html">asking</a> and <a href="http://www.linuxgazette.com/tag/members-faq.html">answering</a> questions. Linux questions only, please.
</STRONG>
<br><em><font color="#7F0000">We make <b>no guarantees</b> about answers, but you can be <b>anonymous</b> on request.</font></em>
<br>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>
</center>
<br></p></center>
<HR>
<!-- BEGIN message -->
<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>LILO problem whith dual linux boot on seperate drives</strong></a>
<dt><A HREF="#tag.2"
><img src="../gx/dennis/bbub.gif" height="28" width="50"
alt="(!)" border="0"
><strong>filter out spam and viruses</strong></a>
<dt><A HREF="#tag.3"
><img src="../gx/dennis/bbub.gif" height="28" width="50"
alt="(!)" border="0"
><strong>The One Remaining (non-Depracated) Use for rsh</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 -->
<P> Greetings, everyone. It's another day, another penguin over here at
The Answer Gang. I'm sorry there are only three messages this time but
I think you'll find them juicy.
<P> Statistics - there were about 460 messages - and almost none of that was
spam thanks to Dan Wilder's hard work keeping the list on a leash. I'd
say the most common reason to not get an answer or merely get grumped at
instead of seeing a useful answer, would be to combine the twin errors
of using HTML based mail, and not telling us what few things you've
looked up first. We can do much better at translating technese to
English than we can do at translating confused-fuzziness to a technical
question.
<P> You folks had a gazillion good tips out there and I'm digging myself out
from under them right now. [Imagine: a computer workroom filled with
little grey envelopes filled with pennies all gabbing about little Linux
tidbits. It's quite a chatterbox.]
<P> But that's hardly fair. The real reason I'm running late and a few
pennies short is that I've been working really hard on the upcoming
LNX-BBC. It's gonna be this year's membership card for the
<A HREF="http://www.fsf.org/">Free Software Foundation</A>. I mean, if you're
not a member then perhaps you should be anyway... but this is a definite plus.
It's still a toy for experts though. More on cool toys for "the rest of us" in
upcoming months. There are lots and lots of good projects out there.
<BLOCKQUOTE><EM>
[It wasn't all Heather's fault. Our FTP server played a game of
"let's not but pretend we did", accepting Heather's Answer Gang upload but not
storing it. Bad FTP daemon, bad! It also has been dying the past few days,
which Dan has been combating via upgrades and logfile analysis. At one point
logrotate was dying and taking the daemon down with it. -Iron.]
</EM></BLOCKQUOTE>
<P> Have fun!
<!-- end hgreeting -->
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
<h5>
<br>Copyright &copy; 2003
<br>Copying license <A HREF="">http://www.linuxgazette.com/copying.html</A>
<BR>Published in Issue 87 of <i>Linux Gazette</i>, February 2003</H5>
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
<SMALL><CENTER><H6 ALIGN="center">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>
</H6></SMALL></CENTER>
<HR>
<P>
<!-- .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~. -->
<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"
>LILO problem whith dual linux boot on seperate drives</H3>
<p><strong>From Rich Price
</strong></p>
<p align="right"><strong>Answered By Matthias Posseldt, Jim Dennis, Mike "Iron" Orr, John Karns, Heather Stern, Benjamin A. Okopnik
<p></strong></p>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
I recently bought a new IDE disk drive and installed it as <TT>/dev/hdb</TT> in my
server.
While leaving my current [<A HREF="http://www.slackware.org/">Slackware</A>] distribution on <TT>/dev/hda</TT>, I wish to
install the <A HREF="http://www.debian.org/">Debian</A> distribution on <TT>/dev/hdb.</TT>
</STRONG></P>
<P><STRONG>
After completing the basic Debian install, I edited the lilo.conf file to
include a second image. The original file was:
</STRONG></P>
<p align="center">See attached <tt><a href="misc/tag/rich-price.slack.lilo-conf.txt">rich-price.slack.lilo-conf.txt</a></tt></p>
<P><STRONG>
The newly modified file is:
</STRONG></P>
<p align="center">See attached <tt><a href="misc/tag/rich-price.slack-debian.lilo-conf.txt">rich-price.slack-debian.lilo-conf.txt</a></tt></p>
<P><STRONG>
when I tested this config file i got:
</STRONG></P>
<p align="center">See attached <tt><a href="misc/tag/rich-price.slack-debian.lilo-complains.txt">rich-price.slack-debian.lilo-complains.txt</a></tt></p>
<P><STRONG>
<TT>/boot/vmlinuz-2.2.20-idepci</TT> does exist on <TT>/dev/hdb1</TT> but not of course on
/dev/hda1.
Is this the problem? If so, how do I access an image on a different hard
drive?
</STRONG></P>
<P><STRONG>
I downloaded the "LILO User's Guide" and read about the alternate image
format:
</STRONG></P>
<pre><strong> image=/dev/hdb1
range=sss-eee
</strong></pre>
<P><STRONG>
where sss-eee is the starting and ending sector range of the image, but I
don't know
how to find out what to use for sss-eee.
</STRONG></P>
<P><STRONG>
Rich Price
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Matthias]
Just mount the corresponding partition and use this path then, e.g.
</blockQuote>
<blockquote><pre>image = /mnt/newdebianroot/boot/vmlinuz-2.2.20-idepci
root = /dev/hdb1
label = Debian
</pre></blockquote>
<blockQuote>
A different option is to separate boot and root partitions and mount the
<TT>/boot</TT> partition in both Slackware and Debian while also keeping
<TT>/etc/lilo.conf</TT> in sync, so that you can easily use the
<TT>/boot/vmlinuz-debian-2.a.b</TT> and <TT>/boot/vmlinuz-slackware.2.x.y</TT> kernel images
and use the <TT>/boot</TT> path. An easy way would be to symlink <TT>/etc/lilo.conf</TT> to
<TT>/boot/lilo.conf</TT> in both installations and you can happily run lilo from
Debian and Slackware.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
I'd personally avoid the esoterica of any "alternate image format"
(if possible) and simply put the desired kernel and any required
initrd (compressed initial RAMdisk) images unto the <TT>/boot</TT> partition
(or into the <TT>/boot</TT> directory of any rootfilesystem) back on <TT>/dev/hda.</TT>
</blockQuote>
<blockQuote>
There is no problem sharing one <TT>/boot</TT> directory among multiple
Linux distributions --- and it's the easiest way to do it.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Thanks to both of you for your answers.
</STRONG></P>
<P><STRONG>
I have sidesteped the problem for now by booting off of a floppy.
But I think Jim's suggestion will make a better long term solution.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Iron]
Jim's method is the easiest and most convenient. However, there's no reason
the other kernel has to be in <TT>/boot</TT> as long as it's mounted somewhere when
"lilo" is run. Older Linux distributions used to put the kernel in <TT>/</TT> by
default.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
I am not a programmer [any more] but I think that an enhansement
to LILO which would allow the use of different file systems for
different boot images would be good. Something like this:
</STRONG></P>
<pre><strong>image = /boot/vmlinuz-2.2.20-idepci
root = /dev/hdb1
imagefs=/dev/hdb1
label = Debian
</strong></pre>
<P><STRONG>
Where imagefs is a new parameter used to specify the file system
that contains the boot image file.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Jim]
Unfortunately this suggestion exhibits a fundamental misunderstanding
of how LILO works. The "image" files are access as regular files,
and thus they must reside on some locally mounted filesystem when you
run <TT>/sbin/lilo.</TT> <TT>/sbin/lilo</TT> then issues ioctl()s to get the low-level
block address information about where the image file's parts are
located. Those raw device/block addresses are written into the map
file (usually found in <TT>/boot</TT>). The address of the map file is written
into the boot block (usually in the MBR of the hard drive).
</blockQuote>
<blockQuote>
Your hypothetical imagefs= would require that <TT>/sbin/lilo</TT> either
incorporate all the code to directly access the device/partition as
a filesystem (which is infeasible for a large number of filesystem and
is just bad engineering --- code duplication for even a single type),
or it would have to do something like: make a temporary mount point,
mount the imagefs, use this temp mount as a relative chroot
point?, then proceed as before. It's VASTLY easier for you to
mount the fs up yourself and simply manually refer the appropriate
entries in your <TT>/etc/lilo.conf</TT> to the kernel image (and initrd images,
etc) before running <TT>/sbin/lilo.</TT>
</blockQuote>
<blockQuote>
In my MANY discussions about LILO I find it convenient to distinguish
between LILO (the whole package) and <TT>/sbin/lilo</TT> (the utility that reads
the <TT>/etc/lilo</TT> file and various command line options and produces/writes
a map file and a bootloader (into the MBR, unto a floppy or into a
filesystem superblock or "logical boot record).
</blockQuote>
<blockQuote>
Run strace on <TT>/sbin/lilo</TT> some time and you may find enlightenment.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [John]
Yes, Linux is nirvana! :^)
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Ben]
I've found that running "strace" <em> _often</em> precedes enlightenment. Also,
like reading the dictionary (who the heck can stop at just one entry?),
it's usually enlightenment on topics far beyond the original one.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Iron]
What would the information be useful for? "lilo" uses the image= path to
determine the kernel's physical location, the boostrapper uses the physical
location, and at no time is <TT>/boot</TT> required to be mounted (except when running
"lilo").
</blockQuote>
<blockQuote>
However, a few programs use <TT>/boot/System.map</TT> (or <TT>/boot/System.map-VERSION</TT>), and
these may behave funny if it's not accessible or is out of sync with the
running kernel. Currently I see that klogd (the kernel logging daemon) has it
open while it's running. But stopping klogd, unmounting <TT>/boot</TT> and restarting
klogd does not cause any errors, although it does generate a log message of:
</blockQuote>
<blockquote><pre>Jan 10 14:55:28 rock kernel: Cannot find map file.
Jan 10 14:55:28 rock kernel: No module symbols loaded.
</pre></blockquote>
<blockQuote>
"man klogd" says it uses System.map to translate the numeric traceback of a
kernel error to a list of functions that were active at the time, which makes
it easier for kernel developers to track down what caused the problem.
</blockQuote>
<blockQuote>
Dan says modprobe also uses System.map. "strings <TT>/sbin/modprobe</TT> | grep
System.map" shows that word exists in the code, although the manpage doesn't
mention it. So you may need <TT>/boot</TT> mounted when loading modules.
</blockQuote>
<blockQuote>
Is there anything else that likes to have System.map around?
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Ben]
Oddly enough, <EM>Netscape</EM>. I remember doing some complicated messing
around with multiple kernels, way back when, where I'd hosed System.map
in some way or another. It didn't seem to affect too many things, but
the annoying error message I got every time I fired up Netscape finally
got me to straighten it all out. I was a young Linux cub then...
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle">
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [John]
For a time I used to unmount the <TT>/boot</TT> partition in the init scripts to
avoid risking corruption of the ext2fs there during normal operation.
Then I noticed the above errors (didn't seem to affect loading modules
though), and switched to remounting as ro instead, which rid me of the
error, and avoids the problem of having it mounted rw. Alternatively I
suppose that one might be able to change the fstab entry to mount it ro.
Not sure if there is a requirement to have it rw in the early boot
process.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Iron]
I have had <TT>/boot</TT> mounted read-only for years and have had no problem.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Heather]
On my multi-distro setup, I also mount <TT>/boot</TT> read-only; depmod tries to
run during every boot, and complains that it cannot write. As long as
I deliberately run depmod while my <TT>/boot</TT> is read-write whenever I'm
adding modules or new kernels, then this is an ignorable warning because
I already did that. When running depmod by hand on a kernel which you
do not yet have booted, you definitely need a copy of its System.map on
hand, for use with the -F parameter. If I fail to do this, the distro
that wants this is a very unhappy camper, because with no depmod
information at all, it cannot load any modules.
</blockQuote>
<blockQuote>
I occasionally build monolithic kernels deliberately, but that's barely
viable with today's huge list of kernel features.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Thanks, Jim.
</STRONG></P>
<P><STRONG>
This information makes LILO much more understandable to me.
It enables me to see why my suggestion doesn't make any sense.
It also makes the light bulb go on about Matthias's original answer
which I admit I didn't understand until now. This is great!
I now have two ways to solve my problem and enough understanding
about what I am doing to finally be dangerous ;-}&gt;
</STRONG></P>
<P><STRONG>
I think that adding something similar to your comments to the LILO
User's Guide would be helpful to part time LINUX hackers like me.
Perhaps in section 3.3.1 a second paragraph could be added saying:
</STRONG></P>
<P><STRONG><BLOCKQuote>
"The image file is accessed as a regular file, and thus it must reside
on a locally mounted filesystem at the time that <TT>/sbin/lilo</TT> is run.
</BLOCKQuote></STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
... kernel and initrd images files are accessed by <TT>/sbin/lilo</TT> ...
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
/sbin/lilo
will then issue ioctl()s to get the low-level block address information
which shows where the image file's parts are located in the file system.
This file system does not have to be on the same physical drive as the
root file system."
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
... but must be accessible to the bootloader code (generally via BIOS functions).
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Did I get it right? Do you think I should suggest this to the maintainers?
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
I've touched it up a bit --- their maintainers would, undoubtedly
tweak it more to their likely if they choose to incorporate it.
</blockQuote>
<blockQuote>
Please feel free to send this to John Coffman and to the maintainers of
the appropriate HOWTOs (as referenced in my earlier post).
</blockQuote>
<blockQuote>
I'd also <EM>highly</EM> recommend pointing them at the years of Linuz Gazette
Answer Guy/Gang material on this topic --- so they can understand how
frequently these questions come up and glean some ideas for how we
people in the "support trenches" have been trying to dispel the
confusion that plagues so many LILO users. (Did I mix too many
metaphors there?)
</blockQuote>
<blockQuote>
In particular if they explain LILO as analogous to programming:
<TT>/etc/lilo.conf</TT> is the "program source", <TT>/sbin/lilo</TT> is the compiler and
the bootloader and map files are "objects" --- then a large number of
people will "get it." Even people with the barest modicum of
(compiler) programming experience understand why changing the source
code doesn't change the program until it's recompiled.
</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"
>filter out spam and viruses</H3>
<p><strong>From Jonathan Becerra
</strong></p>
<p align="right"><strong>Answered By Faber Fedor, Neil Youngman, Kapil Hari Paranjape, Heather Stern
<p></strong></p>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
I'm very new to Linux but like what I see
</STRONG></P>
<P><STRONG>
The object here is to install a software that will filter all my e-mails and
keep out viruses
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Faber]
Look into Amavis (www.amavis.org) and your favorite anti-virus software
(Sophos, McAffee, etc.). If you're using Postfix as your MTA, drop me a
line and I can help you get the three of them working.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
and catch re-occurring spam.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Faber]
Check out Spam Assassin (www.spamassassin.org). It rocks!
</blockQuote>
<blockquote><IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Heather] Since the list which all Answer Gang members are on uses SpamAssassin as one
among several defenses, I think yes - it does
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle"> but it is not infallible.
With any mail filtering answers I encourage you to take a look at its
principles, and decide if you like them, rather than just take someone
else's word on what is or isn't spam.
</blockquote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Neil]
LWN seem to rate bogofilter, see <A HREF="http://lwn.net/Articles/9186"
>http://lwn.net/Articles/9186</A>. I haven't
used it myself.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Kapil]
I currently use "bogofilter" and am very happy with it. There are also
alternatives such as "spamoracle" and "spamprobe". All these three
programs implement Paul Graham's suggestions in "A Plan for Spam".
</blockQuote>
<blockQuote>
As far as I can make out "spamassasin" is a much more general tool that
can easily incorporate the measurements used by Paul Graham.
</blockQuote>
<blockQuote>
The neatness of Paul Graham's approach is that it is entirely
"Bayesian" --- spam mails self-select themselves once we have a
sufficiently large database of spam and non-spam messages. Moreover,
this division is entirely in the hands of the end-user.
</blockQuote>
<blockQuote>
On the other hand since this measurement is made <EM>after</EM> the mail enters
the system it is not very useful if you want to reduce bandwidth
consumption.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
I have 2 NIC cards, etho1 and
etho2. Both were picked up by my install and both work, I can get out to the
Internet with either one. I need help configuring etho1 to be the incoming
route for my e-mails which my software will then pick up and process and
then I want etho2 to send it out to my users.
</STRONG></P>
<P><STRONG>
I have been all over the Internet and in the book stores, I even had to
break down and buy a Linux book for dummies which was no help at all.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Kapil]
I think what you need is to take a hard look at Firewall-HOWTO.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Faber]
(at <A HREF="http://www.tldp.org"
>http://www.tldp.org</A>, in case you didn't know).
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Sound possible?
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Faber]
With Linux, almost anything is possible.
</blockQuote>
<blockquote><IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Heather] Though it may take a while to finish coding... no wait, that's "the
impossible takes a little longer"
<IMG SRC="../gx/dennis/smily.gif" ALT=":D"
height="24" width="20" align="middle">
</blockquote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
I would be so appreciative and so would my head (because then I can quit
banging it against my desk) for any and all help you could provide.
</STRONG></P>
<blockquote><IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Heather] On behalf of the Gang, we hope you heal up soon! You're following good
principles; make all emails have to follow one path into your site,
then place some guardians upon that path to nail the miscreants as they
come through.
</blockquote>
<blockquote>Tune up your firewall to only show services to the outside world which
you really provide, and that needed for your inside people to get to
outside services they use (generally, using IP masquerading will make
this automatic and nearly invisible). If you've got specific hosts
pestering you with spam, get your MTA to blow them off with a "551
too much spam, site blocked" so your mailbox guardians don't have to
waste CPU time on those bozos. Best of luck in the battle against spam.
</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"
>The One Remaining (non-Depracated) Use for rsh</H3>
<p><strong>From Dave Falloon
</strong></p>
<p align="right"><strong>Answered By Jim Dennis, Mike "Iron" Orr, Kapil Hari Paranjape
<p></strong></p>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Hi Answer Guy,
</STRONG></P>
<P><STRONG>
I have a 32 node cluster running <A HREF="http://www.debian.org/">Debian</A> 3.0 (Woody). The primary way we
use these machines is in a batch type submission, kind of a fire an forget
thing, via rsh "&lt;command&gt;".
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
These days the knee jerk response would be: "Don't run rsh; use ssh
instead."
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Agreed, the reason for rsh is that this little cluster is all by itself,
accessed through a "choke host" that is pretty well locked down, only a
handful of users can access it on the external interface.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
However, compute clusters, on an isolated network segment, (perhaps
with one or more multi-homed ssh accessible cluster controller nodes)
are still a reasonable place for the insecure r* tools (rsh, rlogin,
rcp). (rsync might still be preferable to rcp for some workloads and
filesets).
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
I crippled PAM a little to allow this ( changed
one line to be sufficient). This cluster is not a super critical farm so if
things go haywire its not a big deal but it would be nice to figure out why
sometimes you can't connect to the nodes, here is the output from one such
attempt:
</STRONG></P>
<pre><strong>(503)[dave@snavely] ~$ rsh ginzu
Last login: Thu Jan 16 16:37:22 2003 from snavely on pts/1
Linux ginzu 2.4.18 #1 SMP Fri Aug 2 11:20:55 EDT 2002 i686 unknown
rlogin: connection closed.
(504)[dave@snavely] ~$
</strong></pre>
<P><STRONG>
This happened once then when I repeated the command it succeeded, with no
error.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Kapil]
One possible reason for the problem is the assignment of a free pty.
</blockQuote>
<blockQuote>
1. You may be running out of pty's if many processes unnecessarily
open them.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
This is a definate possibility, and I am recompiling a kernel as we speak to
up this limit to 2048.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Kapil]
2. Your tweaking of rsh and PAM was not sufficient to give rsh
permission to open a pty.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Would this produce an intermitten connection drop or would it prevent any
connection at all?
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Kapil]
This would also explain the unable to get TTY name error.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
So how does the chain of events happen? Is this correct; I rsh to a machine
it, pam looks over its rules and see that it is crippled and should allow
this connection with no passwd, passes this on to login which then tries to
assigned a pty but the pty's are all currently used, then it tries to assign
a TTY because there are no ptys, and in my logs I get the can't get TTY name
error?
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Kapil]
No, there is no separate "TTY" assignment. The "pty/tty" pair is what is
assigned for interactive communication.
</blockQuote>
<blockQuote>
Let's see if we can track the sequence of events (the Gang please post
corrections, I am sure I'll go wrong somewhere!):
</blockQuote>
<blockQuote><BLOCKQuote>
Client "rsh" request is usually handled on the server by "inetd" which
then passes this request to "tcpd" which then passes the request to
"rshd".
</BLOCKQuote></blockQuote>
<blockQuote>
O. However, tcpd may refuse the connection if its host_access rules do
not allow the connection. This refusal could be intermittent depending
on whether the name service system is responding (NIS/DNS whatever).
(This possibility has already been mentioned on the list in greater
detail).
</blockQuote>
<blockQuote>
At this point, I looked up the Sun Solaris man page for rshd (none
of the Linux machines here has "rsh" installed!). The following steps
are carried out and failure leads to closing the connection.
</blockQuote>
<blockQuote>
A. The server tries to create the necessary sockets for a connection.
</blockQuote>
<blockQuote>
B. The server checks the client's address which <EM>must</EM> be resolvable
via the name service switch specification (default NIS+/etc/hosts).
</blockQuote>
<blockQuote>
C. The server checks the server user name which <EM>must</EM> be verifiable
via the name service switch specification (default NIS+/etc/passwd).
</blockQuote>
<blockQuote>
D. The server checks via PAM that the either (the client is in <TT>/etc/hosts.equiv</TT>
</blockQuote>
<blockQuote>
and the client user name is the same as the server user name) or
the client username is in .rhosts.
</blockQuote>
<blockQuote>
E. The server tries to acquire the necessary pty/tty's and connects them
to the sockets and the server user's shell (which must exist).
</blockQuote>
<blockQuote>
I am a bit confused about the use of PAM but I think it is also used
in steps C and E through the "account" and "session" entries. The
"auth" entry for PAM is used in "D".
</blockQuote>
<blockQuote>
So it seems like O,A-E need to be checked on your system. My own
earlier suggestion was only about E but the failure could be
elsewhere.
</blockQuote>
<blockQuote>
Temporary failure of the NIS server to respond could affect B and C;
it could even affect E as the "passwd" entry is required to find the
user's shell. Thus, in such situations it is a good idea to run the
name service caching daemon.
</blockQuote>
<blockQuote>
If NFS is used for home directories then temporary failure of the NFS
server to respond could affect D 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"
> [JimD]
So it was a transient (or is an intermittent) problem.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Yup
</STRONG></P>
<P><STRONG>
I have adjusted the <TT>/etc/inet.conf</TT> by adding the .500 to the rsh line
nowait:
</STRONG></P>
<pre><strong>shell stream tcp nowait.500 root /usr/sbin/tcpd /usr/sbin/in.rshd
</strong></pre>
<P><STRONG>
in order for these machines to allow more jobs to be run at a time.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
This adjusts inetd's tolerance/threshold to frequent connections
on a given service. It simply means that inetd won't throttle back
the connections as readily --- it will try to service them even if
they are coming in fast and furious. In this case it will allow up to
500 attempted rsh connections per minute (about 8 per second).
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
That really doesn't adjust anything about the number of concurrent
jobs that a machine can run --- just the number of times that the
inetd process will accept connections on a give port before treating
it as a DoS (denial of service) attack or networking error, and
throttling the connections.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
I adjusted this because we ran into lots of problems with inet dropping
connections, I just wanted to make sure that it behaved like it was supposed
to, ie you didn't know of some immediately relevant bug in this line
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
In your example this is clearly NOT the problem. It made the
connection and then disconnected you. Thus it wasn't inetd refusing
the connection, but the shell process exiting (or being killed by the
kernel).
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Iron]
Just to clarify, I think Jim is saying that it's not inetd or tcpd refusing
you, because otherwise rlogin wouldn't have started at all, and it (rlogin)
ouldn't have been able to print the "last login:" and kernel version lines.
</blockQuote>
<blockQuote>
By the way, when tcpd doesn't like me, it waits a couple seconds (usually
doing reverse DNS lookup), and then I see "Connection closed by foreign host"
with no other messages.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
One possibility is that we have everyone's home drive on NFS and if the NFS
was slow to respond that may cause rlogin to find no home directory and
refuse the connection. Is that a realistic possibility?
</STRONG></P>
<P><STRONG>
One interesting turn of events is the message you get in auth.log :
</STRONG></P>
<P><STRONG><BLOCKQuote>
Jan 20 15:41:31 ginzu PAM_unix[31073]: (login) session opened for user dave
by (uid=0)
Jan 20 15:41:31 ginzu login[31073]: unable to determine TTY name, got
/dev/tty6
</BLOCKQuote></STRONG></P>
<P><STRONG>
These machines have no video cards/keyboards/otherinput, really they are
processor/harddrive/ram/NIC and thats all so it would make sense to comment
out the getty lines in inittab for these boxes ... correct?
</STRONG></P>
<P><STRONG>
That would at the very least stop the auth.log and daemon.log spamming, I
think
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [Iron]
If inetd is not listening to the port at all and no other daemon is, you'll
get an immediate "Connection refused" error. This is confusing because it
doesn't mean it doesn't like you, it means there's nobody there to answer the
door.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
I'd run vmstat processes on the affected nodes (or all of them) for
a day or two --- redirect their output to local files or over the
network (depending one which will have the least impact on your
desired workload) and then write some scripts to analyze and/or graph
them.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
I have started collecting info on these machines.
</STRONG></P>
<P><STRONG>
Can you think of why these machines behave like this? Could it be a load
average problem, maybe its network related, is it a setup problem? Any
ideas would be appreciated
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
It's not likely to be a networking or setup issue. Your networking
seems to work. Things seem to be configured properly for moderate
workloads, so we have to find out which host resources are under the
most pressure. So it's probably a loading problem.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Its not a loading issue the system is pretty good at evening out load across
the pool of machines
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
(Note I did NOT say "load average" problem. "load average" is simply
a measure of the average number of processes that were in a runnable
(non-blocked) state during each context switch over the last minute,
and five and fifteen minutes. A high load average should NOT result
in processes dying as you've described --- but often indicates a
different resource loading issue. Sorry to split hairs on that point
but this is a case were understanding that distinction is important).
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
These machines can get a little bagged at times but the login failure
happens regardless of the load of a given host.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
As always you should be checking your system logs. Hopefully there'll
be messages therein that will tell you if the kernel killed your
process and why. Otherwise you can always write an "strace" wrapper
around these executables. It will kill your performance, but, if you
can reproduce the problem you'll be able to see what the process died.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
After a look in the logs ( I can't believe I didn't do this earlier ), I
found a lot of messages about getty trying to use <TT>/dev/tty*</TT>, no such device,
which makes sense considering they have no input/output hardware like
video/keyboard, etc.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
Some tweaks to the setup might help.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
There are basically four resources we're concerned about here:
memory, CPU, process table, and file descriptor table (space and
contention). (I'm not concerned about I/O contention in this case
since that usually causes processes to block --- performance to
go very slowly. It doesn't generally result in processes dying like
you've described here).
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
vmstat's output will tell you more. You can probably make some guesses
based on your workload profile.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
If you're running many small jobs spawning from one (or a small number
of) dispatcher processes (on each node) you might be bumping into
rlimit/ulimit issues. Read the man page for your shell's ulimit
built-in command, and the ulimit(3) man page for more details on that.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Ulimits have been adjusted already we ran into file descriptor limits before
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
If you're running a few large jobs than its more likely to be a memory
pressure problem --- though we'd expect you'd run into paging/thrashing
issues first. There are cases where you can run out of memory without
doing any signficant paging/swapping (where the memory usage is on
non-swappable kernel memory rather than normal process memory).
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
By the way, you might want to eliminate tcpd from your configuration
(remove the references to <TT>/usr/sbin/tcpd</TT> from your inetd.conf file).
This will save you an extra fork()/exec() and a number of file access
operations on each new job dispatched. (The use of rsh already assumed
you've physically isolated this network segment with very restrictive
packet filters and anti-spoofing --- so TCP Wrappers is not useful
in your case and is only costing you some capacity, albeit small).
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
You might even eliminate rsh/rlogin and go with the even simpler
rexec command!
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Some times people will run an interactive job on this cluster, so rsh/rlogin
is still nice to have. We have no real policy about what can or cannot be
run on these machines, like I had said it is more of a playground for our
researchers, than a critical cluster.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
It goes without saying that you may wish to eliminate, renice, or
reconfigure any daemons you're running on these nodes. For example,
you can almost certainly eliminate cron and atd from the nodes (since
your goal is to dispatch the jobs from one or a few central
cluster control nodes. <EM>They</EM> could run a small number of cron/atd
processes and dispatch jobs across the cluster as appropriate.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
True, but really it doesn't seem related, I can't see an interaction between
login and cron that would drop your connection. Although it is nice to cut
down bloat where you can.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
The klogd/syslogd daemons are worth extra consideration. I'd
strongly consider running syslog under 'nice' and giving it lowest
possible priority. I'd also consider tweaking the syslog.conf to
remove the leading "-" (dashes) from any local log file names
(so that they will be written asynchronously rather than with
<TT>fsync()</TT> calls after every write to the logs).
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
I'd even consider eliminating all local files from these configurations
and having these nodes do all their logging over the net (which being
UDP based, might result in some lossage of log messages). However,
that depends heavily on your workload and network topology and
capacity. Basically you might have bandwidth to burn (Gig ethernet,
for example) and this might be a reasonable tradeoff.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
We are on a switched full duplex 100 base TX, network. The logs on the
switches report that in the last 3 months we have only went above 80% of the
switches bandwith once, so I think we have enough bandwidth to support logs
over the net.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
I'd also consider setting the login shell for these job handling
accounts to ash (or the simplest, smallest shell that can successfully
process your jobs). bash, particularly with version 2.x is a pretty
"resourceful" (read "bloated") program which may not be necessary
unless you're doing some fairly complex shell scripting.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
A possibility, but as I had said some of our researchers will run an
interactive job so they want a full shell.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
Also in your shell/jobs you might want to make some strategic use of
the exec built-in command. Basically in any case where the shell
or subshell doesn't have a command subsequent to one of your external
binaries --- exec the binary. This saves a <TT> fork()</TT> system call, and
means that the shell processes are NOT taking up memory, file descriptors,
and entries in the process table just waiting for other executables to
exit.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
I'd also eliminate PAM and look for the older r* and login suite.
The traditional <TT>/bin/login</TT> program does an exec*() system call to
run your shell. The PAM based suite performs a <TT> fork()</TT> and then an
<TT>exec()</TT> --- and the <TT>/bin/login</TT> program remains in order to perform
post logout cleanup. It is quite likely that you are not interested
in these more advanced features provided by PAM's approach.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
PAM is overkill but I don't think it is the culprit.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
Incidentally, another point to consider is your local filesystems.
You may want to mount as many of them as possible in "read-only" mode
and all of them with the noatime option. Both of these tweaks can
considerably reduce the amount of work the system is doing to maintain
your filesystem consistency and the (rarely used) access time stamps.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
You may also want to consider using the older ext2 filesystem rather
than any of the journaling filesystem choices. This depends on your
data integrity requirements, of course, but the journaling done by
ext3, reiserfs, XFS and others does come at a significant cost.
</blockQuote>
<blockQuote>
(Note: In some other cases, where intensive use of local filesystems
is part of the workload, XFS or reiserfs might be VASTLY better than
ext2 --- for various complicated reasons).
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Reiser is working fine on these nodes. I have found a significant
improvement over ext2 for the majority of tasks run on these boxes.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
Depending on your application, you might even want to consider
recompiling it using older, simpler versions of libc/libm (since
many of the advanced features of GNU glibc 2.x may be useless
for your computations). Of course if the application is multi-threaded
then you may needs glibc 2.x' re-entrancy.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Not really possible, in a lot of cases we are running some third party
commercial software which is very closed source.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
It's possible that you need to do some kernel tuning. This might
involve writing some magic values into the sysctl nodes under
<TT>/proc/sys</TT> (or running the systune or Linux powertweak utilities).
It might also involve rebuilding your kernel, possibly with a few
static variables changed or a few scalability patches applied.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
(In this case, "scalability" is a loaded term --- since it means
much different things to differing workloads).
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
I think the real problem is that we are having a bad interaction with some
piece of software and rlogin/login/getty?/init or something and that causes
the connection to be dropped.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
You can find numerous hints about Linux kernel performance
tweaking using Google! <A HREF="http://www.google.com/linux"
>http://www.google.com/linux</A>
</blockQuote>
<blockQuote>
Here's a few links:
</blockQuote>
<blockQuote><DL><DT>
The C10K problem
<DD><A HREF="http://www.kegel.com/c10k.html"
>http://www.kegel.com/c10k.html</A>
</DL></blockQuote>
<blockQuote>
Written and maintained by Dan Kegel, originally in response
to the infamous "Mindcraft" fiasco wherein Microsoft paid an
"independent" lab to prove that MS Windows was "faster" or
"more scalable" than Linux.
</blockQuote>
<blockQuote>
Dan is/was one of the advocates for improving the Linux kernel
in a number of key areas regardless of if Mindcraft's
credibility.
</blockQuote>
<blockQuote>
CITI: Projects: Linux scalability - University of Michigan
</blockQuote>
<blockQuote>
<A HREF="http://www.citi.umich.edu/projects/linux-scalability"
>http://www.citi.umich.edu/projects/linux-scalability</A>
Run by Peter Honeyman (a legendary UNIX programmer).
</blockQuote>
<blockQuote><DL><DT>
SGI - Developer Central Open Source: Scalability Project
<DD><A HREF="http://oss.sgi.com/projects/linux-scalability"
>http://oss.sgi.com/projects/linux-scalability</A>
</DL></blockQuote>
<blockQuote><DL><DT>
IBM developerWorks: Linux: Linux Kernel Performance &amp; Scalability
<DD><A HREF="http://www-106.ibm.com/developerworks/linux/library/l-kperf"
>http://www-106.ibm.com/developerworks/linux/library/l-kperf</A>
</DL></blockQuote>
<blockQuote>
The problem with all of these links is that they are not focused on
the set of requirements specific to your needs. They are more
concerned with webserver, database, SMP, and single-server scalability
rather than Beowulf style cluster performance.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
Of course you could read the information at <A HREF="http://www.beowulf.org"
>http://www.beowulf.org</A>
Strictly speaking it doesn't sound like you're really running a Beowulf
cluster --- you're dispatching jobs via rsh rather than distributing
computation load using MPI, PVM or similar libraries. However some of
the same configuration suggestions and performance observations might
still apply.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Most of the tweaking described has already been implemented
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
In general there isn't any silver bullet to increasing the capacity
of your cluster. You have to find out which resources are being
hit hardest (the bottlenecks), review what is using those resources,
find ways to eliminate as much of that utilization as possible
(removing tcpd, using a simpler/smaller shell, running terminal
processes via exec, changing to a non-journaling filesystem,
eliminating unneeded daemons) and try various tradeoffs that shift
the utilization of a constrained resource (local filesystem I/O vs.
pushing things out to the network, memory/cache and indexed data
structures vs CPU and linear searches).
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Capacity is not the objective, I would say reliability ( not necessarily
100%, but better than 50%, for sure
<IMG SRC="../gx/dennis/smily.gif" ALT=":)"
height="24" width="20" align="middle"> is more my goal.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
That's really all there is to performance tuning. Finding what's
using which resources. Finding what you can "not" do. Finding ways
to tradeoff one form of resource consumption with another. Of course
the black magic is in the details (especially when it comes to
poking new values into nodes under <TT>/proc/sys/vm/</TT> --- read the
Documentation/sysctl* text files in your Linux kernel sources for some
hints about <EM>that</EM>)!
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Perhaps a more detailed view of the cluster will give you more to work on.
There are really 34 machines to this cluster, one choke node that stands
between the outside world and the inside nodes. 32 machines (identical
hardware), dual Pentium 3 550 MHz's, 256 megs SDRAM (133MHz), single Maxtor
12 GB hardrive (7200 RPM ATA 66), 3com 3c590 ethernet card, identical
kernel's across the board, 2.4.18, SMP. One single sun machine, that
serves, NIS, NFS, and DNS, and home brewed batch server ( keeps track of
jobs and hosts loads and assigns jobs to hosts via rsh ). After searching
some more websites I found that some people have a problem with the
services.byname map in NIS. Could that be an issue here? I have adjusted
the inittab by commenting out the lines:
</STRONG></P>
<pre><strong># &lt;id&gt;:&lt;runlevels&gt;:&lt;action&gt;:&lt;process&gt;
#1:2345:respawn:/sbin/getty 38400 tty1
#2:23:respawn:/sbin/getty 38400 tty2
#3:23:respawn:/sbin/getty 38400 tty3
#4:23:respawn:/sbin/getty 38400 tty4
#5:23:respawn:/sbin/getty 38400 tty5
#6:23:respawn:/sbin/getty 38400 tty6
</strong></pre>
<P><STRONG>
Because these machines have no video/input.
</STRONG></P>
<P><STRONG>
Thanks for all your help so far. I hope all this new info helps you get a
better idea of whats going on.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
You could build a new kernel, setting CONFIG_UNIX98_PTY_COUNT=2048
(apparently their maximal value).
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
Running a compile with this right now, thanks
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
I'd also try to eliminate NIS from these systems. I'd look at using
rsync to replicate the various <TT>/etc</TT> configuration files across the
cluster (passwd, group, hosts, services, et al). Failing that make
sure that you have the nscd (NIS name services cache daemon) properly
configured on the client nodes.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
I have been waffling on moving this farm over to Cfengine and losing NIS for
about three months, I think I am going to get started on that right away.
Have you guys used cfengine, or do you have any suggestions for config
management tools?
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
I'd also try to eliminate NFS, or at least try to minimize it's use
especially for home directories. I'd also eliminate the automounting
if at all possible. This requires that the users work a little
smarter, manually transferring their data/input files down to the
proper nodes, and pulling the results back therefrom.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
I have suggested this, but the tools (third party, very badly designed) some
of the research guys use need to write to the home drive, and in order to
take advantage of more than one node that would suggest that the home drive
be in two places at once (NFS, SMB or whatever). The way it works is that
one node will modify a model file, another will immediately pick up the
change and adjust what it is doing and modify the file more until the proper
mathematical model for a given project is found. Then they use that model
to figure out a whole range of useful information, at least thats how its
supposed to work.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
If that's not feasible, at least configure these systems so that the
home directories are not automounted, replicate the basic suite of
"dot files" out to them and have a lower mount point provide the shared
data.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
I don't think I can.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
I'd also be quite wary of configuring the systems to allow NFS crossing
the isolated segment and out into filers on your network. This sounds
like a supremely bad idea allowing anyone with local root access on any
node on the outer network to impersonate any users, dropping files into
their directories which will be executed/sourced by shell session in
the inner network.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
NFS traffic never leaves the clusters subnet, think of it as a hole in my
network covered by one node that runs ssh with 6 local accounts. Once you
log in to that firewall node you need to then rsh or ssh out the other
interface to either a node in the cluster or the old sun machine serving
NIS/NFS. All traffic on the local subnet stays on the local subnet. Once a
researcher has a proper model defined they have to rcp/scp that file to the
firewall machine, and then scp (rsync over ssh, or whatever) it to their
destination (rcp is not enabled outside of my protected subnet).
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
HEIGHT="28" WIDTH="50" BORDER="0"
> [JimD]
However, I think you're getting closer to the real heard of the problem
by looking into Kapil's suggestion regarding your PTY availability.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
HEIGHT="28" WIDTH="50" BORDER="0"
>
I'll know shortly, thanks everyone you guys rock!
</STRONG></P>
<P><STRONG>
Dave
</STRONG></P>
<!-- end 3 -->
<!-- *** BEGIN copyright *** -->
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<CENTER><SMALL><STRONG>
<h5>
<br>Copyright &copy; 2003
<br>Copying license <A HREF="">http://www.linuxgazette.com/copying.html</A>
<BR>Published in Issue 87 of <i>Linux Gazette</i>, February 2003</H5>
</STRONG></SMALL></CENTER>
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<HR>
<table border="1"><tbody><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>
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<small>...<i>making Linux just a little more fun!</i></small>
</td><td width="380">
<center>
<BIG><BIG><STRONG><FONT
COLOR="maroon">News Bytes</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="http://www.linuxgazette.com/authors/conry.html">Michael Conry</A></STRONG></BIG>
</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">
February 2002 <i>Linux Journal</i>
</font>
</h3>
<img alt="[issue 106 cover image]" src="misc/bytes/lj-cover106.png" width="200" height="268" align="left" hspace="20">
The February issue of <a href="http://www.linuxjournal.com/"><i>Linux
Journal</i></a> is on newsstands now.
This issue focuses on enterprise computing. Click
<a href="http://www.linuxjournal.com/modules.php?op=modload&amp;name=NS-lj-issues/issue106&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>.
<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">You win some...
</FONT>
</H3>
<P>
Jon Johansen,
a Norwegian programmer who has been
<a href="http://www.eff.org/IP/Video/DeCSS_prosecutions/Johansen_DeCSS_case/20021206_eff_pr.html">facing criminal charges</a>
as a result of his involvement in the creation of the DeCSS computer code
for playing CSS encoded DVDs, has been
<a href="http://www.eff.org/IP/Video/DeCSS_prosecutions/Johansen_DeCSS_case/20030107_eff_pr.html">acquitted on all counts</a>.
Jon was charged under a law that relates to breaking into other people's
property, a law usually invoked in cases where attackers have attempted to
break into another party's computer system. The law had never before been
applied to prosecute a defendant for breaking into his own property, and in
this case the Norwegian court ruled against the prosecutor on all charges,
<a href="http://www.aftenposten.no/english/local/article.jhtml?articleID=466519">
citing Norwegian law protecting a consumer's rights to use his own
property</a>. An English
<a href="http://www.eff.org/IP/Video/DeCSS_prosecutions/Johansen_DeCSS_case/20030109_johansen_decision.html">translation of the judgement</a> has been made online by
<a href="http://www.eff.org/">EFF</a>.
<P>
The war is not over yet, however, and Norwegian prosecutors are set to
<a href="http://www.eff.org/IP/Video/DeCSS_prosecutions/Johansen_DeCSS_case/20030120_eff_pr.php">appeal the verdict</a>.
If the request for an appeal is granted, the case will be heard again
before the Norwegian appeal courts.
Film industry lawyer, Charles Sims,
<a href="http://www.reuters.com/newsArticle.jhtml?type=topNews&storyID=2006339">
was keen to assert</a> that a US resident would have been breaking the law
if they did what Jon Johansen did.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">You lose some
</FONT>
</H3>
<P>
The United States Supreme Court
<a href="http://cyberlaw.stanford.edu/lessig/blog/archives/01-618o.pdf">
has ruled to support</a>
the 20 year extension of copyright terms that was granted two years ago.
The balance of opinion went 7-2, with dissenting opinions coming from
Justices
<a href="http://www.copyright.gov/docs/eldredd.pdf">
Stevens</a>
and
<a href="http://www.copyright.gov/docs/eldredd1.pdf">
Breyer</a>.
<P>
The constitutional challenge began when Eric Eldred, who
<a href="http://209.11.144.65/eldritchpress/">
distributes public-domain books online</a>,
found that he would have to
<a href="http://www.nashuatelegraph.com/Main.asp?SectionID=25&SubSectionID=377&ArticleID=71766">remove some of these works</a>
as their copyrights had been reactivated by an extension granted by the US
Congress.
There is a large amount of information on the case available at
<a href="http://eldred.cc/">
eldred.cc</a>. Lisa Rein has also compiled a
<a href="http://www.onlisareinsradar.com/archives/eldred_vs_ashcroft/">
selection of reports and resources</a>
related to the case.
<P>
The issue at stake in the Eldred case was whether it was constitutional for
Congress to extend copyrights in this way. There are compelling arguments
on both sides of this argument (with some more compelling if you own
billions of dollars in copyrighted works and want your business to be
subsidised by the public), but the court has ruled that
Congress had (and has) the right to make this extension. This does not
mean that the all is lost. Governments in democratic countries are
supposed to be responsive to the desires of citizens,
and to act accordingly. Thus, it is important for citizens to make their
opinions on these issues apparent to their elected representatives. Simply
because a government <em>can</em> pass a law, does not mean that they
<em>will</em> pass the law, especially if they can expect to pay a steep
price at the ballot box next election time.
<P>
This is particularly relevant to European readers. European copyrights
last for 50 years. What makes this significant is that about 50 years ago
was the beginning of the modern era music recording, so from now on, a
steady stream of high quality recordings by still-popular artists will be
entering the public domain. Industry bodies are
<a href="http://www.nytimes.com/2003/01/02/international/02CND_COPY.html">
lobbying to have the terms of copyrights extended</a>
and are bandying words like piracy around to cloud the waters.
As
<a href="http://www.tompaine.com/feature.cfm/ID/7048">
pointed out</a>
by Dean Baker, extending copyrights retrospectively on works does nothing
to encourage creativity or
<a href="http://librenix.com/?inode=2747">
"To promote the Progress of Science and useful Arts"</a>. Instead, it
"<a href="http://www.tompaine.com/feature.cfm/ID/7048">
raises costs to consumers and leads to increased economic
inefficiency</a>". This straight-forward truth will not stop industry
monopolists and their quislings from attempting to steal the labour of
humanity from the public commons, and then
<a href="http://story.news.yahoo.com/news?tmpl=story2&u=/nm/20030116/media_nm/industry_copyright_dc">
telling us it was all for our own good</a>.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">DMCA
</FONT>
</H3>
<P>
Your monthly serving of DMCA madness this time involves garage doors. It
would appear that at least one firm believes that
<a href="http://yro.slashdot.org/article.pl?sid=03/01/16/1311232&mode=nested&tid=99">
making universal garage door remotes</a> is a breach of the DMCA and is
prepared to spend some legal money on the idea. That wasn't enough? Well,
here's a second helping:
<a href="http://www.lexmark.com">Lexmark</a> is
<a href="http://www.theregister.co.uk/content/7/28811.html">
invoking the DMCA</a>
in an attempt to hobble the printer cartridge remanufacturing industry.
Edward Felten has
<a href="http://www.freedom-to-tinker.com/archives/000248.html">
concisely explained</a>
that a major issue here is the whole principle of interoperability.
Interestingly, the European Parliament has
<a href="http://www.geek.com/news/geeknews/2002Dec/gee20021223017885.htm">
voted in a new law</a>
banning such "smart" printer cartridges as they make recycling more
difficult and expensive. Bruce Schneier
<a href="http://www.counterpane.com/crypto-gram-0301.html">
predicts a trade war</a>, but even if it does not come to that, it will be
interesting to see where the story goes. Also highlighted by Bruce, and
worth reading, is the EFF's guide
<a href="http://www.eff.org/IP/DMCA/20030102_dmca_unintended_consequences.html">
Unintended Consequences: Four Years under the DMCA</a>.
<a name="links"></a>
<p><hr><p>
<!-- =================================================================== -->
<center><H3><font color="green">Linux Links</font></H3></center>
<P>
Linux Magazine article on
<a href="http://www.linux-mag.com/2002-10/jfs_01.html">
journaling filesystems</a>.
<P>
Linux Planet article discussing
<a href="http://www.linuxplanet.com/linuxplanet/tutorials/211/1/">
basic Linux network security</a>.
<P>
Some links highlighted by
<a href="http://www.linuxtoday.com/">
Linux Today</a>:
<ul>
<li>
<a href="http://www.newsfactor.com/perl/story/20432.html">
How secure is secure shell?</a>
</li>
<li>
Wired on
<a href="http://www.wired.com/news/infostructure/0,1377,57306,00.html">
a penguin shaped future</a>.
</li>
<li>
DistroWatch has a
<a href="http://www.distrowatch.com/cd.php">
list of Linux-on-CD projects</a>.
</li>
<li>
Fortune asks
"<a href="http://www.fortune.com/fortune/technology/articles/0,15114,409836,00.html">
How do you stop an army of penguins?</a>"
</li>
<li>
Linux Orbit
<a href="http://www.linuxorbit.com/modules.php?op=modload&name=Reviews&file=index&req=showcontent&id=27">
Gnu/Linux media player</a> round-up.
</li>
</ul>
<P>
<a href="http://www.jobmart.com/Linux/Resumes/index.html">
Linux Job Market</a>.
<P>
Lawrence Lessig discusses whether
<a href="http://www.redherring.com/insider/2003/01/copycats011003.html">
derivative works are always a bad thing</a>
for the owners of the original work. Japanese experience indicates they
may be beneficial.
<P>
The Register has
<a href="http://www.theregister.co.uk/content/4/29002.html">a report</a>
on businesses gathering to fight Hollings' copy controls
<P>
Some links from NewsForge:
<ul>
<li>
Article on the
<a href="http://newsforge.com/article.pl?sid=03/01/20/1432234&mode=thread&tid=23">
use of Linux by electricity companies</a>
</li>
<li>
<a href="http://newsforge.com/newsforge/03/01/07/2134248.shtml?tid=46">
Training is available</a> for new commercial Security-Enhanced Linux
</li>
<li>
Workspot Linux:
<a href="http://newsforge.com/article.pl?sid=03/01/22/1733244&mode=thread&tid=23">
instant and portable "magic"</a>.
</li>
</ul>
<P>
<a href="http://www.virtualsky.net/daves">
Dave's Desktop</a>
is one Linux user's quest to share information on some of the helpful apps
for Linux he has come across recently.
<P>
Howard Wen at O'Reilly is on a quest to find good Linux games.
On the way, he
<a href="http://www.onlamp.com/pub/a/onlamp/2003/01/02/falconseye.html">
found Falcon's Eye</a>
and
<a href="http://linux.oreillynet.com/pub/a/linux/2003/01/16/jaakko.html">
talked to the game's creator</a>
<P>
Linux Server Hacks:
<a href="http://www.oreilly.com/catalog/linuxsvrhack/chapter/index.html">
Backups</a>
<P>
Both
<a href="http://www.linuxjournal.com/article.php?sid=6562">
Linux Journal</a>
and
<a href="http://www.desktoplinux.com/articles/AT8221013471.html">
DesktopLinux</a>
have dealt with Linux's relevance to senior citizens.
<P>
Some links from <a href="http://lwn.net/">Linux Weekly News</a>:
<ul>
<li>
<a href="http://lwn.net/Articles/16858/">
LWN 2002 Linux Timeline</a>
</li>
<li>
<a href="http://lwn.net/Articles/18472/">
LWN Five-Year Timeline</a>
</li>
<li>
Linux is
<a href="http://techupdate.zdnet.com/techupdate/stories/main/0,14179,2908199,00.html">
gaining market share</a> in government offices around the world.
</li>
<li>
A <a href="http://lwn.net/Articles/19535/">list of Linux-related
books</a> that are published under open source licenses.
</li>
</ul>
<P>
<a href="http://www.linux.org.tw/CLDP/NEW/">
The Chinese Linux Documentation Project</a> (CLDP) has included LDP's and
Gnu's documents, translated them into Chinese. It also involve the Linux Gazette.
<P>
Some links from <a href="http://slashdot.org/">Slashdot</a>:
<ul>
<li>
Using a
<a href="http://slashdot.org/articles/03/01/01/2151236.shtml?tid7">
manual typewriter on a computer</a> as an aid for an RSI sufferer
</li>
<li>
<a href="http://www.opensource.org/halloween/halloween8.php">
Halloween 8</a>
A Microsoft memo inspired by the threat of governments turning to Linux.
</li>
<li>
<a href="http://shirky.com/writings/zapmail.html">
Customer-owned broadband infrastructure</a>.
</li>
<li>
Robot brain surgeon
<a href="http://www.smh.com.au/articles/2003/01/15/1042520673704.html">
runs Linux</a>. I feel safer already!
</li>
<li>
<a href="http://speed.vpizza.org/~jmeehan/balloon/">
A Linux weather balloon</a>
</li>
</ul>
<P>
<a href="http://www.wikipedia.org/">
Wikipedia</a>, the free, contributor-maintained on-line encyclopedia,
has
<a href="http://www.wikipedia.org/wiki/Wikipedia%3A2003_Press_Release">
reached its second birthday and 100,000 articles</a>.
<a name="conferences"></a>
<p><hr><p>
<!-- =================================================================== -->
<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.
<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>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>Desktop Linux Summit</b><BR>
<td valign=top>February 20-21, 2003<BR>San Diego, CA<BR>
<a href="http://www.desktoplinux.com/summit/" target="_blank">
http://www.desktoplinux.com/summit/</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>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>Software Development Conference & Expo</b><BR>
<td valign=top>March 24-28, 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>Linux Clusters Institute (LCI) Workshop</b><BR>
<td valign=top>March 24-28, 2003<BR>Urbana-Champaign, IL<BR>
<a href="http://www.linuxclustersinstitute.org/" target="_blank">
http://www.linuxclustersinstitute.org/</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 DC 2003</b><BR>
<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>Linux on Wall Street Show & Conference</b><BR>
<td valign=top>April 7, 2003<BR>New York, NY<BR>
<a href="http://www.linuxonwallstreet.com" target="_blank">
http://www.linuxonwallstreet.com</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>FOSE</b><BR>
<td valign=top>April 8-10, 2003<BR>Washington, DC<BR>
<a href="http://www.fose.com/" target="_blank">
http://www.fose.com/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>LinuxFest Northwest 2003</b><BR>
<td valign=top>April 26, 2003<BR>Bellingham, WA<BR>
<a href="http://www.linuxnorthwest.org/" target="_blank">
http://www.linuxnorthwest.org/</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 28-30, 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>The Fourth International Conference on Linux Clusters:
the Linux HPC Revolution 2003</b><BR>
<td valign=top>June 18-20, 2003<BR>Las Vegas, NV<BR>
<a href="http://www.linuxclustersinstitute.org/Linux-HPC-Revolution"
target="_blank">
http://www.linuxclustersinstitute.org/Linux-HPC-Revolution</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>Portland, OR<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>
<tr><td valign=top>
<b>Linux Lunacy</b><BR><i>Brought to you by Linux Journal and
Geek Cruises!</i><br>
<td valign=top>September 13-20, 2003<BR>Alaska's Inside Passage<BR>
<a href="http://www.geekcruises.com/home/ll3_home.html" target="_blank">
http://www.geekcruises.com/home/ll3_home.html</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>Software Development Conference & Expo</b><BR>
<td valign=top>September 15-19, 2003<BR>Boston, MA<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>PC Expo</b><BR>
<td valign=top>September 16-18, 2003<BR>New York, NY<BR>
<a href="http://www.http://www.techxny.com/pcexpo_techxny.cfm"
target="_blank">
http://www.techxny.com/pcexpo_techxny.cfm</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>September 16-18, 2003<BR>Toronto, Ontario<BR>
<a href="http://www.comdex.com/canada/" target="_blank">
http://www.comdex.com/canada/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>LISA (17th USENIX Systems Administration Conference)</b><BR>
<td valign=top>October 26-30, 2003<BR>San Diego, CA<BR>
<a href="http://www.usenix.org/events/lisa03/" target="_blank">
http://www.usenix.org/events/lisa03/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>HiverCon 2003</b><BR>
<td valign=top>November 6-7, 2003<BR>Dublin, Ireland<BR>
<a href="http://www.hivercon.com/" target="_blank">
http://www.hivercon.com/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
<tr><td valign=top>
<b>COMDEX Fall</b><BR>
<td valign=top>November 17-21, 2003<BR>Las Vegas, NV<BR>
<a href="http://www.comdex.com/fall2003/" target="_blank">
http://www.comdex.com/fall2003/</A><BR>
<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>
</table>
<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">MEN Micro's New M-Modules
</FONT>
</H3>
<P>
Two new digital input M-Modules from
<a href="http://www.men.de/">
MEN Micro</a> have been released. They have been designed to
meet tough environmental and safety specifications and were developed
specifically for railway
applications, but they can be deployed in a broad range of
industrial systems where shock, vibration, temperature and harsh
environments are a concern.
<P>
The M-Modules, which are designated M31 and M32, each provide 16 binary
channels to a control platform. Because they conform to the ANSI-approved
M-Module standard, they can be installed in a number of standard bus-based
systems, including CompactPCI, PXI, VMEbus and PCI, or they can be used in
small busless systems.
<P>
Software drivers for the M31 and M32 are available for Windows, Linux,
VxWorks, QNX, RTX and OS-9.
<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">Ark
</FONT>
</H3>
<P>
<a href="http://www.arklinux.org/">
Ark Linux</a> is a
<a href="http://www.ofb.biz/modules.php?name=News&file=article&sid=191">
new distribution</a>, led by former Red Hat employee Bernhard
Rosenkraenzer. It is based on Red Hat 7.3/8.0, and free alpha
<a href="http://www.arklinux.org/download.php">
downloads</a>
are available.
<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/2002/51/">
reported</a> the
<a href="http://lists.debian.org/debian-cd-0212/msg00177.html">
announcement</a>
by Steve McIntyre that he
has created a set of update CD images that contain new and updated
packages from 3.0r1.
<P>
<hr width="20%" noshade>
<P>
Also
<a href="http://www.debian.org/News/weekly/2003/01/">
from Debian Weekly News</a> is a report on
the availability of an
<a href="http://polydistortion.net/urls/new-debian-packages.rss">
RSS feed of new Debian packages</a>.
<P>
<hr width="20%" noshade>
<P>
Bdale Garbee, current Debian project leader,
<a href="http://www.theage.com.au/articles/2003/01/08/1041989994382.html">
has been interviewed</a> by Australian newspaper The Age.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">Eagle
</FONT>
</H3>
<P>
<a href="http://www.geocities.com/eaglelinux">
Eagle Linux</a>
is a how-to based Linux distribution offering full open source
documentation assisting users in creating personal embedded, floppy, and CD
based bootable distributions.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">Gentoo
</FONT>
</H3>
<P>
<a href="http://www.gentoo.org">
Gentoo Linux</a>
has announced the second release candidate for the upcoming 1.4 version of
Gentoo Linux. New in 1.4_rc2 is the Gentoo Reference Platform: a suite of
binary tarballs that allow for faster initial
<a href="http://www.gentoo.org/doc/en/gentoo-x86-install.xml">
installation</a>. Currently X, GNOME, KDE, Mozilla, and OpenOffice,org are
available as binary installations for x86 architectures and ppc
architectures with others to follow.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">Mandrake
</FONT>
</H3>
<P>
Mandrake 9.0 has been reviewed recently
<a href="http://www.theregister.co.uk/content/4/28776.html">
by The Register/NewsForge</a>
and
<a href="http://www.ofb.biz/modules.php?name=News&file=article&sid=189">
by Open for Business</a>.
<P>
<hr width="20%" noshade>
<P>
It has been widely reported in the past month that Mandrake is currently
experiencing acute financial problems. This has lead company management to
apply for
<a href="http://www.theregister.co.uk/content/4/28895.html">
Chapter-11 style protection</a>. The purpose of this is to give the
company some respite to allow it to reorganise its finances without
pressure from creditors.
The French courts have
<a href="http://www.mandrakesoft.com/company/press/briefs?n=/mandrakesoft/news/2406">
approved the plan</a> and hopefully the company will
in a better position to make positive progress after this period.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">SCO
</FONT>
</H3>
<P>
<a href="http://www.sco.com">
The SCO Group</a>
have announced plans to work with
<a href="http://www.wincor-nixdorf.com/usa">
Wincor Nixdorf</a>
to provide Linux-based
retail point-of-sale (POS) solutions to retailers in North America. This
relationship gives retail customers an economical, reliable choice by
combining the functionality and flexibility of Wincor Nixdorf hardware with
the stability and reliability of SCO operating systems.
The joint retail solutions will rely on Wincor Nixdorf's BEETLE POS family and
SCO's Linux POS solution, SmallFoot.
<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 annnounced the availability of a desktop Linux product that gives users
the full functionality of the Microsoft Office suite of applications. SuSE
Linux Office Desktop, available from January 21, is intended for small
companies looking for an easy, preconfigured desktop -- as well as for
personal users with little or no Linux experience.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">UnitedLinux
</FONT>
</H3>
<P>
<a href="http://www.unitedlinux.com">
UnitedLinux</a>
has announced
plans to integrate the full
<a href="http://www.osdl.org">
OSDL</a> Carrier Grade Linux (CGL) 1.1
feature set for UnitedLinux 1.0, delivering
enhanced abilities to develop and deploy carrier-grade
applications in a standardized Linux environment.
<P>
Developed by UnitedLinux integration partner SuSE Linux with HP,
IBM and Intel, the features -- targeted initially for use on
Intel-based hardware platforms -- enable telecommunications
providers to develop and deploy new products and services on
standards-based, modular communications platforms.
<P>
<hr width="20%" noshade>
<P>
<a href="http://www.lpi.org">
LPI</a>
a professional certification program for
the Linux community, and
<a href="http://www.unitedlinux.com">
UnitedLinux LLC</a>
have signed a
cooperative agreement to market a UnitedLinux professional
certification program.
<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">KDE
</FONT>
</H3>
<P>
KDE 3.1 has
<a href="http://www.kde.org/announcements/announce-3.1.html">
been released</a>.
<P>
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">Understanding the Linux Kernel, 2nd Edition
</FONT>
</H3>
<P>
O'Reilly & Associates has released a new edition of
<em>
<a href="http://www.oreilly.com/catalog/linuxkernel2/?CMP=EM13459">
Understanding the Linux Kernel</a>
</em>
which has been updated to cover version
2.4 of the kernel. 2.4 differs significantly from version 2.2:
the virtual memory system is new, support
for multiprocessor systems is improved, and whole
new classes of hardware devices have been added.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">Aqua Data Studio 1.5
</FONT>
</H3>
<P>
<a href="http://www.aquafold.com/">
AquaFold</a>
has announced the
release of Aqua Data Studio 1.5, a free database tool supporting all major
database platforms, including Oracle 8i/9i, DB2 7.2/8.1, Microsoft SQL
Server 2000/7.0, Sybase ASE 12.5, MySQL, PostgreSQL and generic JDBC
drivers. Aqua Data Studio also supports all major Operating Systems
designed to run Sun Microsystem's Java Platform such as Microsoft Windows,
Linux, OSX and Solaris.
Aqua Data Studio is designed to speed up the
development of database and application developers by providing them with an
elegant and consistent interface to all databases on all platforms.
<a href="http://www.aquafold.com/downloads.html">
Free downloads</a>
and
<a href="http://www.aquafold.com/screenshots.html">
screenshots</a>
of Aqua Data Studio are available online.
<P> <hr> <P>
<!-- =================================================================== -->
<H3><IMG ALT=" " SRC="../gx/bolt.gif">
<FONT COLOR="green">OpenMFG
</FONT>
</H3>
<P>
<a href="http://www.openmfg.com">
OpenMFG</a> is
a company
using open source software to bring enterprise resource planning (ERP)
applications to small manufacturers, has welcomed the first ten members of
the Open Partners Program.
<!-- =================================================================== -->
<!-- =================================================================== -->
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2003, Michael Conry.
Copying license
<A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 87 of <i>Linux Gazette</i>, February
2003</H5>
</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 Ultimate Editor</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/bint.html">Stephen Bint</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<P><CENTER><B><I>Somewhere, out there, is a C++ programmer whom destiny has
chosen to be our liberator.</I></B></CENTER>
<H3>The Ultimate Editor's Time Has Come</H3>
<P>How can it be that Windows users are spoiled for choice of excellent
text editors, while not one decent one exists for the Linux console?
Linux is a better OS, supported by better programmers who are dedicated
to producing better tools for eachother's benefit. The text editor is
the programmer's most important and frequently used tool. Yet Linux
console editors are rubbish. How can this be?
<P>Those of us who migrate from windows to Linux expect a text editor,
at the very least, to allow selection of text with the mouse and to have
mouse-sensitive menus and dialogs. Of all the editors only mcedit, the
editor built in to the Midnight Commander disk navigator, has these
features. The rest have no dialogs and either no mouse interface or a
very limited, stupid one.
<P>Yet even mcedit has a fatal flaw. If there is anything about its
behaviour you don't like, or a function it lacks which you would like to
add, you will find that reverse-engineering the source to solve that
problem is more difficult than writing your own text editor from
scratch. Unfortunately mcedit is quite basic, so it really needs added
functionality and there is no easy way to add it.
<P><I>What is the point of Open Source being open, if it is so complicated
and poorly documented as to be impenetrable to anyone but the author?</I>
<P>Let's face it, we are all the same. We love writing code and hate
writing docs. Writing slick algorithms is fun but explaining how they
work to newbies is a bore. Yet if someone were to take the trouble to
write an editor with maintenace in mind and build in a simple way to add
C++ functions to menus, it might be the last editor ever written. No one
would bother to write a text editor if one existed, whose behaviour was
easy to change and to which any function could be added.
<H3>Blasphemy</H3>
<P>Stallmanist Fundamentalists may say at this point, emacs is
extensible. So it is, but you need to learn a second language to extend
it. Besides that, the basic editor has a crude and confusing user
interface which cannot be improved by adding lisp modules.
<P>Some of us who aspire to use Linux are ordinary people, not software
supermen. It is cruel and unnecessary to tell someone struggling to
learn their first language, that they must simultaneously learn a second
language in order to make their editor work they way they want it to.
<P>It will never do. Emacs isn't a tool. It's an intelligence test. It
is time stupid people fought back against the elitists who are so
clever, they find learning emacs a breeze. Notice that you do not have
to learn how to use mcedit. It does what you expect so there is nothing
to learn.
<P>The Ultimate Editor would be what emacs should have been: an
extensible editor with an intuitive mouse-and-menu interface.
<EM>[Editor's note: emacs was born before mice and pulldown
menus were invented.]</EM> Instead of
complicating the picture with a second language, the extensions would be
written in C++. It would come with a programmer's guide, explaining how
to install your own menu commands and also describing the anatomy of the
source so that you can easily locate the module you are after if you
want to change something about its basic behaviour. It would be a
do-it-yourself editor kit.
<H3>O, Beautiful Tool</H3>
<P>If the Ultimate Editor existed, this is what it would be like. You
would download it and build it and find it has the basic functionality
of mcedit. It would have mouse selection, mouse-sensitive menus and a
file open dialog box that allows you to navigate the disk by
double-clicking on directories.
<P>It would have few functions: File Open, File Save, File Save As,
Exit, Cut, Copy, Paste, Delete and Help. At first there would be no
search function, but the README would explain that the source file for
the search function is included and would give simple instructions for
how to add it. The lines to be added to the source would already be
there, but commented out, to make it easy to add the search function.
<P>To add the search function you would have to:
<P>1. Move its source file to the editor's src directory
<P>2. Declare the function at the top of main.cc like this:
<PRE> int show_search_dlg();</PRE>
<P>3. Add a line to main() (actually uncomment a line) like this:
<PRE> ed.add_menu_cmd( show_search_dlg, "Search", "Edit", F2_key, SHIFT_PRESSED );</PRE>
<P>...which installs a command labelled "Search" on the "Edit" menu,
which can be activated directly by pressing Shift-F2.
<P>4. In the Makefile, add (uncomment) a compile rule for the source
file and add its name to the list of objects to be linked.
<P>5. Run Make and find that the search function is now on the menu.
<P>Having followed this procedure, even a complete newbie will know how
to write their own menu functions. The editor will be a global variable,
(C++ object) accessible in any source file the user writes, through its
header file. Its member functions will report the states of all its
internal variables, such as cursor position and area selected. The text
array containing the file being edited will be accessible as a member
variable, so that the file can be scanned and modified within the user
function.
<H3>Living Colour</H3>
<P>Usually, the logic of colourization is imposed on users. Some editors
offer a dialog to change the colours and to add keywords, but the logic
is dictated by the author.
<P>The Ultimate Editor will offer an easy way for users to write their
own colourization routines. Apart from enabling people to colourize rare
and eccentric languages, this feature will unlock the hidden potential
of colourization.
<P>Think how many ways you could choose to colour source and what an aid
to reverse engineering it could be. Depending on your purpose, you might
want to colour identifiers according to which header file they are
declared in, or whether they are automatic or allocated, or use colours
to indicate their scope. You might choose to have several colouring
schemes installed and switch between them with hot keys.
<P>To make colourizing simple, the Ultimate Editor will store its files
in file arrays which contain two arrays of strings - one for the text
and another for the colours. The file array will keep the sizes of the
strings in these arrays synchronized so that, for every character stored
in the text array, there is always a byte representing its colour at the
same co-ordinates in the colour array.
<P>The editor will always draw on the colour array when it refreshes, so
all the programmer has to do in order to colour a character at certain
co-ordinates, is change the value in the colour array at those same
co-ordinates and refresh the display.
<H3>Ninety Percent Widgets</H3>
<P>From the user's point of view, dialog boxes appear to be a small part
of a text editor. From the programmer's perspective, it is the other way
round. The editable fields which appear in dialogs are fully functional
editing windows with a couple of features disabled. So to write the
Ultimate Editor is really to write the Ultimate Widget Library.
<P>A well-written widget library with good docs is more than an
accessory to an extensible editor. If users become familiar with the
library in order to improve the editor, they can use it to produce
configuration dialogs which assist non-experts in configuring other
software, by asking simple questions and writing out their wishes in a
config file.
<P>Linuxconf is a very important configuration tool, but it is fading
like a dead language because it is hard to use. Because it is hard to
use, it is hard to get enthusiastic about improving it. Users and
programmers both drift instead towards other, distribution-specific
configuration programs. If linuxconf was rewritten to show
mouse-sensitive dialogs that behave like proper dialogs (like X-windows
dialogs), it might grow to include modules to enable clueless newbies to
configure any popular package.
<P>Do you not agree, that the main obstacle to the popularity of Linux,
is esotericism? I mean, no-one bothers to write software for newbies
because only software experts ever use Linux. The growth of Linux is
being prevented by an elitist Catch-22. If idiot-friendly configuration
programs were not important to the popularity of an OS, would Microsoft
have lavished so much time and money on them?
<P>Rewriting linuxconf with a simple but modern widget library would be
the first step to making what it should be - a project that never ends.
It should be continually growing as more modules are added, until it
becomes the one-stop-shop through which all Linux software can be
configured by children.
<H3>A Little Help</H3>
<P>I want this challenge to be open to anyone who knows C++. Because
interfacing with the mouse, keyboard and colour-text screen under Linux
is a low-level nightmare, I have produced an interface library which
makes it as simple under Linux as it is under DOS. I recommend it over
Slang for the purpose of writing an editor for several reasons.
<P>First, the Slang source (including docs and demo programs) zipped is
740k, whereas my library's source zips to 42k. Second, Slang does not
report mouse movement, so a Slang program cannot drag-select with the
mouse. Third, the colouring system in Slang is complicated, but mine
represents the screen as an EGA-style buffer of character/colour byte
pairs.
<P>I wrote my library after an attempt to use Slang myself drove me to
the conclusion that its all-platform capability generated an
unacceptable overhead and took less than full advantage of the potential
of the Linux console. I don't doubt that the author of Slang is a better
programmer than me, but I have produced a library specifically to serve
programmers who want to produce the first adequate editor for the Linux
console.
<P>You can download it here: <A href="http://members.lycos.co.uk/ctio/">http://members.lycos.co.uk/ctio/</A>
<P>And now that interfacing with the console is as simple under Linux as
it ever was under DOS, the obstacle to Linux editors having the same
basic features as DOS editors has been removed. Now anyone who knows C++
can do something great. To produce the editor and widget library I have
described might change the course of the history of free software, by
rolling out a red carpet to entry-level programmers.
<H3>Invent the Wheel</H3>
<P>I am constantly being told that there is no need to reinvent the
wheel. A ship could sail the Atlantic, powered only by my sighs. Let me
assure you, I will march up and down the High Street blowing a trumpet
and proclaiming at the top of my voice, "NO NEED TO REINVENT THE WHEEL!"
on the day that someone actually produces a ROUND WHEEL.
<P>In theory, any Open Source editor can be hacked and made perfect, but
we are still waiting for a mouse-aware console editor which can be
hacked and improved by programmers with I.Q.s under 170. Without
adequate documentation, Open Source is a Closed Book to ordinary
mortals.
<H3>Destiny</H3>
<P>What are you, C++ programmer? Someone with the power to build
abstract machines, an inventor that has transcended the limitations of
the material world that crushed the dreams of human inventors of every
generation before this? The citizens of the beautiful city of Free
Software scrape along on square wheels and you could solve their
problem.
<P>If you are sitting on your flabby backside thinking, "Nyaahh. It's
not for me", then who is it for? Not me, I'm homeless. I have had access
to a computer long enough to write the interface library, but now I am
living in a tent and the closest I get to a computer is occasional
internet access at a day centre for the unemployed. That is why it can't
be me. Why can't it be you?
<P>It might be your destiny to be the author of that Ultimate Editor,
the last editor ever written. Perhaps no more than a month after the
importance of free software has been recognised and Stallman's face is
carved on Mount Rushmore, they may have to blow it off with dynamite and
carve yours on there instead.
<H2>Reference</H2>
<P><STRONG><A href="http://www.s-lang.org/">Slang</A></STRONG>, by John
E. Davis. Slang appears to have eclipsed curses, as the
keyboard/mouse/colour text interface library most programmers would
recommend. If you are dead clever, you might find a way to use the
subset of Slang purely concerned with the console interface, which is
part of the <A href="http://www.ibiblio.org/mc/">Midnight Commander</A>
source. It is smaller and allows text selection at the Linux console, while
still offering limited functionality on less capable terminals, even
telnet windows!
<P><STRONG><A href="http://members.lycos.co.uk/ctio/">CTIO</A></STRONG>,
by Stephen Bint. By far the simplest and best console interface library
I have ever written. Only works at the Linux console and DOS, not in
rxvt/xterm nor telnet windows (but it's only 42k). Read about my struggle
to write it <A href="http://www.linuxgazette.com/issue86/bint.html">
here.</A>
<P><STRONG><A href="http://www.gnu.org/software/emacs/emacs.html">emacs</A></STRONG>,
by Richard Stallman. A millstone in the history of free software.
<!-- *** BEGIN author bio *** -->
<P>&nbsp;
<P>
<!-- *** BEGIN bio *** -->
<P>
<img ALIGN="LEFT" ALT="[BIO]" SRC="../gx/2002/note.png">
<em>
Stephen is a homeless Englishman who lives in a tent in the woods. He eats out
of bins and smokes cigarette butts he finds on the road. Though he once worked
for a short time as a C programmer, he prefers to describe himself as a "keen
amateur".
</em>
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<CENTER><SMALL><STRONG>
Copyright &copy; 2003, Stephen Bint.
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Published in Issue 87 of <i>Linux Gazette</i>, February 2003
</STRONG></SMALL></CENTER>
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<P>
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<EM>These cartoons are scaled down to minimize horizontal scrolling.
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<P> Recent HelpDex cartoons are at Shane's web site,
<A HREF="http://www.shanecollinge.com/">www.shanecollinge.com</A>, on
the <A HREF="http://www.shanecollinge.com/Linux/">Linux</A> page.
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<P>&nbsp;
<P>
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<P>
<img ALIGN="LEFT" ALT="[BIO]" SRC="../gx/2002/note.png">
<em>
Part computer programmer, part cartoonist, part Mars Bar. At night, he runs
around in a pair of colorful tights fighting criminals. During the day... well,
he just runs around. He eats when he's hungry and sleeps when he's sleepy.
</em>
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Published in Issue 87 of <i>Linux Gazette</i>, February 2003
</STRONG></SMALL></CENTER>
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<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>
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These cartoons were made for es.comp.os.linux (ECOL), the Spanish USENET
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<BIG><BIG><STRONG><FONT COLOR="maroon">Quick-Start Networking</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/howell.html">Edgar Howell</A></STRONG>
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<H1>
Quick-Start Networking
</H1>
<H2>
Contents
</H2>
Introduction
<BR>1. Ethernet
<BR>2. Ssh
<BR>3. Screen
<BR>4. File Transfer
<BR>5. Nfs
<BR>6. Samba
<BR>7. PCMCIA
<BR>8. Further Reading
<BR>9. A Future without Windows?
<H2>
Introduction
</H2>
<P>
Over the holidays I finally had a block of time large enough to
work on a network at home. But getting started is always my
biggest problem and it took a while to understand what had to be
done on which machine. In retrospect it was quite easy to get
started.
<P>
This article is essentially little more than my notes, taken
during the experience, less false starts. To the best of my
knowledge it documents what I had to do and will be my reference
if the need arises to repeat any of this.
<P>
To avoid inflating this unnecessarily and because I'm really just
an experienced newbie, almost nothing is explained. There are
references to some relevant articles but I assume you know how to
find the standard documentation.
<P>
To my mind there is no reason for anyone with two or more computers
not to have them networked. My first step was with an Ethernet
card for the PC, a cross-over cable, and a PCMCIA Ethernet card,
all for 87.50 euro. Once that was working, another PCMCIA card
(should have known by the price that it was Windows-only), 8-port
switch and 3 3-meter cables cost 67.50 euro. Roughly $160 wasn't
bad. And it shouldn't cost much more than $25 to connect 2 PCs
point-to-point.
<P>
The current status of this home office network is as follows:
<LI> Toshiba 486 500MB/24MB, SuSE 8.0 (kernel 2.4.18-4GB) without X
<LI> PC Pentium 166 2x4GB/32MB, SuSE 6.3 (kernel 2.2.13)
<LI> Toshiba AMD 4GB/64MB, SuSE 8.0 (kernel 2.4.18-4GB) or Windows 98
<P>
By the way, the asymmetry in the following is not due to anything
inherent in networking or the different Linux kernels. Rather,
the 486 will one day be my portal to the Internet. It shouldn't
be able to do much of anything other than responding to someone
it knows. On the other hand the other two should have no
restrictions.
<P>
Other than that, be careful: this is merely intended to get up and
running as quickly as possible. Everything else has been pretty
much ignored. Consider this just a small but important first step.
Your next step has to be the relevant documentation because this is
quite superficial!
<H2>
1. Quick-Start - Ethernet
</H2>
<P>
Other than a PCMCIA problem (see below), installing and configuring
Ethernet is rather straight-forward. To keep things simple I
started out with a cross-over cable, i.e. point-to-point, and
moved on to a switch only after everything else was known to work.
<P>
Rather than having each machine connect to the network at boot,
there are scripts in /root to run when it is time to connect.
Here are the relevant scripts and files from two of the machines
(less comments and stuff not relevant here):
<P>
Toshiba 486
<PRE>
/etc/hosts: 127.0.0.1 localhost
192.168.0.99 Toshiba486.Lohgo Lohgo486
192.168.0.100 ToshibaAMD.Lohgo LohgoAMD
192.168.0.101 PC.Lohgo LohgoPC
/etc/hosts.allow: sshd: 192.168.0.100, 192.168.0.101
/root/eth-up: #!/bin/bash
/sbin/ifconfig eth0 192.168.0.99 \
broadcast 192.168.0.255 \
netmask 255.255.255.0 up
</PRE>
<P>
Pentium 166
<PRE>
/etc/hosts: 127.0.0.1 localhost PC
192.168.0.99 Toshiba486.Lohgo Lohgo486
192.168.0.100 ToshibaAMD.Lohgo LohgoAMD
192.168.0.101 PC.Lohgo LohgoPC
/etc/hosts.allow: sshd: 192.168.0.100
portmap: 192.168.0.100
lockd: 192.168.0.100
rquotad: 192.168.0.100
mountd: 192.168.0.100
statd: 192.168.0.100
/root/eth-up: #!/bin/bash
/sbin/insmod rtl8139
/sbin/ifconfig eth0 192.168.0.101 \
broadcast 192.168.0.255 \
netmask 255.255.255.0 up
</PRE>
<P>
The following are the same on all 3 machines:
<PRE>
/etc/hosts.deny: ALL : ALL
/root/eth-down: #!/bin/bash
/sbin/ifconfig eth0 down
/root/eth-stat: #!/bin/bash
/sbin/ifconfig eth0; /bin/netstat -r
</PRE>
<P>
The extra entries for the P166 in /etc/hosts.allow are to support
nfs. And insmod in /root/eth-up is due to the Ethernet card in
the PC vs PCMCIA on the notebooks.
<P>
Be aware that SuSE at installation has an option to "re-organize"
/etc/hosts that defaults to CHECK_ETC_HOSTS=yes in /etc/rc.config.
My suspicion is that this is what can cause the 192-IP-address to
be replaced by a 127-address for the host itself in /etc/hosts on
reboot. I don't reboot often enough to feel like checking this
out. But if you get an inexplicable inability to access the
network, do verify the contents of this file.
<H2>
2. Quick-Start - Ssh
</H2>
<P>
Without a doubt this is the most complex of the Linux facilities
described here but is the key to a couple of things that are
extremely useful and it certainly should be set up, for both
convenience and security.
<P>
Prerequisites/definitions:
<LI> "local" is the machine whose keyboard you want to use
<LI> "remote" is the machine whose keyboard you don't want to use
<LI> "&lt;user&gt;" has been set up on both machines
<LI> "&lt;host&gt;" is the 3rd column of the entry for the "remote" host
in /etc/hosts on the "local" machine
<LI> the entries in /etc/hosts.allow and /etc/hosts.deny on the
"remote" machine permit use of sshd from the "local" machine
<LI> use of the mount command does mean playing disk-jockey between
the two machines as appropriate.
<LI> the following is based on SuSE 6.3 (2.2.13) and 8.0 (2.4.18-4GB)
<P>
This is what you have to do if you don't bother to set ssh up:
<PRE>
Remote Local Comment
&lt;logon as user also known to remote host&gt;
ssh &lt;host&gt;
warning:... SOMETHING NASTY
yes accept it
&lt;password&gt;
</PRE>
<P>
This is setup:
<PRE>
Remote Local Comment
&lt;logon as user also known to remote host&gt;
/usr/bin/ssh-keygen
accept default: .ssh/identity
no passphrase
mount /floppy
cp .ssh/identity.pub /floppy/
umount /floppy
logon as &lt;the same user&gt;
mkdir .ssh if necessary
mount /floppy
cp /floppy/identity.pub .ssh/authorized_keys
cp /etc/ssh/ssh_host_key.pub /floppy/known_hosts
umount /floppy
mount /floppy
cp /floppy/known_hosts .ssh/
umount /floppy
vi .ssh/known_hosts
add &lt;host&gt; at start of line and
remove root@&lt;host&gt; at end
</PRE>
<P>
And this is what you have to do to logon after setting things up:
<PRE>
Remote Local Comment
&lt;logon as user also known to remote host&gt;
ssh &lt;host&gt;
</PRE>
<P>
Note that the host key is generated as part of system installation
(with SuSE anyhow). And there can be differences in directory
structure (SuSE's kernel 2.2 didn't have 'ssh' under 'etc').
Also note that this is just intended to get someone unfamiliar
with ssh up and running. Do not blindly follow these steps if you
have used ssh before! In particular most 'cp's certainly ought to
be 'cat ... &gt;&gt;'. In the office at home I don't want a passphrase
to begin work on a different machine, but you might.
<H2>
3. Quick-Start - Screen
</H2>
<P>
Although it has been mentioned in Linux Gazette several times and
I actually did play with it briefly, the need for screen wasn't
at all obvious to me. Given 6+ vt's and X running on at least
two others with unlimited windows under whatever window manager
one has running, it seemed just another level of complexity.
<P>
The need became obvious as the network at home began taking shape.
The rationale behind screen boils down to this: if you start
sessions on remote machines under screen, they remain available
to you as long as the remote machine isn't shut down -- independent
of what happens on the communication link or your local machine.
Like one of my PCMCIA Ethernet cards only works under Windows and
I can thus only connect one of the notebooks to the PC at a time,
if the AMD is also running Linux, as it usually is -- but no need
to shut the 486 down, just eject the card, pop it into the AMD and
screen keeps sessions active on the 486 for later access.
<P>
To start screen:
<PRE>
screen -R restart session if available, otherwise start one
</PRE>
<P>
Within screen (not at all apparent, it hides well) use Ctrl-a
followed by:
<PRE>
? help
w show list of windows
n switch to next window
c create new window
d disconnect
A assign title to window
</PRE>
<H2>
4. Quick-Start - File Transfer
</H2>
<P>
If you are using ssh, you can get rid of rsh -- and telnet and
ftp as well for that matter. Here are a couple of alternatives
that to me are more convenient than the lot.
<P>
Netcat is a nifty little tool, analogous to cat. You start it to
receive a file on one machine
<PRE>
netcat -vv -l -p &lt;port&gt; &gt; &lt;file&gt;
</PRE>
<P>
and then tell the other machine what to send
<PRE>
netcat -vv -w 10 &lt;host&gt; &lt;port&gt; &lt; &lt;file&gt;
or
tar -czvf - &lt;directory&gt; | netcat -vv -w 10 &lt;host&gt; &lt;port&gt;
</PRE>
<P>
Use netstat and /etc/services to find an available port. The
option "-w 10" tells the sender to terminate the connection after
10 seconds of inactivity and the option "-vv" lets you verify
that the correct number of bytes was sent and received.
<P>
While netcat holds promise for scripts to backup to a different
machine as the network at home gradually takes shape, Midnight
Commander has amazing facilities for the things one simply has to
do by hand.
<P>
If ssh has been set up properly, the following entered in the
command line makes mc's active panel point to the same user on
the "other" machine -- yes, "#sh" not "#ssh", unfortunately
<PRE>
cd /#sh:&lt;host&gt;
</PRE>
<P>
And if the other side has anonymous ftp running, the following should be
fairly self-explanatory
<PRE>
cd /#ftp:www.tldp.org/
</PRE>
<H2>
5. Quick-Start - NFS
</H2>
<P>
I played around with nfs and it works but unfortunately my notes
are non-existant (basically just check-marks in the printout of
the HOWTO). As I recall, besides installing the relevant package
on client and server all that was needed was to edit /etc/exports
on the PC (server) as follows:
<PRE>
/home 192.168.0.100(rw,root_squash,sync,insecure)
/tmp 192.168.0.100(rw,root_squash,sync,insecure)
</PRE>
See also /etc/hosts.allow under 1. Ethernet, above.
<P>
At installation SuSE has a number of options to be selected, many
(all?) of which wind up in /etc/rc.config. Here is an excerpt of
those relevant to nfs:
<PRE>
START_PORTMAP="yes"
NFS_SERVER="yes"
USE_KERNEL_NFSD="yes"
USE_KERNEL_NFSD_NUMBER="4"
NFS_SERVER_UGID="no"
REEXPORT_NFS="no"
</PRE>
<P>
On the AMD (client) I added the following to /etc/fstab:
<PRE>
192.168.0.101:/home /Rhome nfs noauto,users,sync 0 0
192.168.0.101:/tmp /Rtmp nfs noauto,users,sync 0 0
</PRE>
<P>
At that point the mount command works with /Rhome etc. just as
well as /floppy or any other entry in fstab. One minor annoyance
is that user ID's must be the same on all machines using nfs.
This was not a problem for me because, when installing Linux, I
create the few users in the same order.
<H2>
6. Quick-Start - Samba
</H2>
<P>
Given the difficulty of keeping track of what one is doing under
Windows, particularly with false starts and things that turn out
to be wrong or simply irrelevant, this needs to be taken with a
large grain of salt. It assumes that the driver for the PCMCIA
card has been installed, if relevant. And if the terminology is
slightly obscure, that is due to my translating from the German
versions of Windows.
<P>
The following is what was necessary to enable logon to the PC
from the AMD under Samba, i.e. from Windows 98 to Linux 2.2.13
(SuSE 6.3). With appropriate adjustments the same steps worked
in the other direction, i.e. from Windows 95 to Linux 2.4.18-4GB
(SuSE 8.0). But note these differences:
<LI>encrypt passwords: 98: yes; 95: no
<LI>path to smb.conf: 2.4: /etc/samba; 2.2: /etc
<LI>path to smbpasswd: 2.4: /etc/samba; 2.2: /etc
<LI>path to netlogon: 2.4: /usr/local/samba; 2.2: /var/lib/samba
<PRE>
Part 1 - Linux
edit /etc/smb.conf
[global]
workgroup = Lohgo
encrypt passwords = yes
smb passwd file = /etc/smbpasswd
password level = 8
username level = 8
socket options = TCP_NODELAY
domain logons = yes
domain master = yes
os level = 65
preferred master = yes
wins proxy = no
wins support = yes
hosts allow = 192.168.0.100 127.
[homes]
comment = Home Directories
read only = no
browseable = no
[netlogon]
comment = Network Logon Service
path = /usr/local/samba/netlogon
public = no
writeable = no
browseable = no
[profiles]
path = /home/%U/profile
guest ok = yes
browseable = no
confirm validity, should show no errors
testparm | less
create user w/password
smbpasswd -a web
verify user enabled
smbpasswd -e web
start Samba
smbd -D
nmbd -D
at this point from the client -- under
Linux, not Windows -- the following
should give a meaningful response
smbclient -L LohgoPC
and the following should give you
ftp-like access
smbclient //LohgoPC/web
</PRE>
<PRE>
Part 2 - Windows98
control panel | network | configuration
add | client for microsoft network
properties
Windows NT-domain: Lohgo
quick logon
add | protocol | microsoft | tcp/ip
properties | set IP-address
IP-address: 192.168.000.100
Subnet address: 255.255.255.000
primary network logon: client for Microsoft network
control panel | network | identification
computer name: LohgoAMD
workgroup: Lohgo
description: ToshibaAMD.Lohgo
control panel | passwords | user profiles
users can customize: both
reboot
if using PCMCIA the following puts
a symbol on the task bar with which
the PCMCIA card can be removed
&lt;insert PCMCIA Ethernet card and wait for lights to settle down&gt;
the following works ONLY after TCP/IP
has been set up, shows configuration
start | run | winipcfg
test connection from within a dos-box
ping -n 5 192.100.0.101
edit c:\windows\hosts.sam
127.0.0.1 localhost
192.168.0.101 lohgopc
edit c:\windows\lmhosts.sam
192.168.0.101 lohgopc
</PRE>
<P>
At this point after booting, Windows will ask you to logon, which
you can either do with a user known to Samba or cancel to use
Windows without the network as before. Now, however, the pop-up
window opened by Ctrl-Esc includes near the bottom a line to
logoff that afterwards provides the same logon prompt as booting.
And the entries in the task bar -- in the home directory, anyhow
-- tell you who and where you are, as in
<P>
"Explorer - &lt;user&gt; at &lt;host&gt;"
<P>
where "&lt;host&gt;" is the 3rd column of the entry for the Linux
machine in /etc/hosts on the Linux machine.
<P>
Symbolic links work quite nicely. The following executed within
the home directory of some user makes a directory -- even on a
different partition -- on the Linux machine available to that
user on the Windows machine:
<P>
ln -s /dos/f/pictures pictures
<P>
Due to a shortage of resources on the PC and the fact that I have
no real use for Windows anyhow, I use the following scripts to
start and stop the Samba daemons on the PC as needed:
<PRE>
/root/samba-up: #!/bin/bash
/usr/sbin/smbd -d3 -l /tmp/sbd.log
/usr/sbin/nmbd -D -d0 -o -l /tmp/sbd.log
/root/samba-down: #!/bin/bash
kill -s SIGTERM $(ps aux | grep mbd \
| grep -v grep | awk '{print $2}')
</PRE>
Once you have this working, it won't take you 5 minutes to set up
a network printer.
Uncomment (or add) the following to smb.conf:
<PRE>
[printers]
comment = All Printers
browseable = no
printable = yes
public = no
read only = yes
create mode = 0700
directory = /tmp
</PRE>
And then spend some time with the archaic data entry system on the
Windows machine:
<PRE>
control panel | printer | new printer
network printer | search
network environment | Pc
hpdj-a4-raw
manufacturer: HP
printer: HP OfficeJet
</PRE>
Shut down and re-start Samba and you're in business.
<H2>
7. Quick-Start - PCMCIA
</H2>
<P>
To be honest I have no idea whether this is generally applicable
or is specific to SuSE (8.0). And it was only the 2.4 kernel
that had problems with PCMCIA, not 2.2 strangely enough. Also,
it has nothing to do with networking per se. But if you're going
to connect a notebook to your network, you'll probably have to
confront the alphabet monster. And a PCMCIA Ethernet card makes
a delightful docking station.
<P>
Omitting many details, I initially failed to note an inconsistency
with references to irq 5 and 10 that later led to tons of error
messages. But this was due to having inserted the PCMCIA card
before starting the installation of Linux.
<P>
In my case at least, by not inserting the PCMCIA card before
starting installation, there was a reference to only one irq which
led to my doing the following.
<P>
After initial boot in /etc/sysconfig/pcmcia add
<PRE>
PCMCIA_PCIC="i82365"
PCMCIA_PCIC_OPTS="irq_list=10"
</PRE>
and then run /sbin/SuSEconfig and reboot.
<P>
However, installing the PCMCIA software before doing this causes
the notebook to hang irrevocably on boot. The only way to boot
is by giving LILO the parameter NOPCMCIA=yes. Instead, I installed
the PCMCIA software after SuSEconfig and before reboot.
<P>
After that, inserting the PCMCIA card produces a couple of beeps
and it works as advertised. Since this is my first personal
experience with Ethernet, I can't comment on alternatives but the
D-Link DFE-650TXD PCMCIA Ethernet card works well, Linux-to-Linux
anyhow (a couple of hours sending stuff over the network before
risking the wretched "Recovery CD-Rom" to make Windows 98 work
again) and has lots of LEDs to let you know what is going on.
<P>
Here is the output from /sbin/cardctl config and ident.
<P>
CONFIG:
<PRE>
Socket 0:
not configured
Socket 1:
Vcc 5.0V Vpp1 0.0V Vpp2 0.0V
interface type is "memory and I/O"
irq 10 [exclusive] [level]
function 0:
config base 0x0400
option 0x60 status 0x00 copy 0x00
io 0x0300-0x031f [auto]
</PRE>
<P>
IDENT:
<PRE>
Socket 0:
no product info available
Socket 1:
product info: "D-Link", "DFE-650TXD", "Fast Ethernet", "Rev. A1"
manfid: 0x0149, 0x0230
function: 6 (network)
</PRE>
<H2>
8. Further Reading
</H2>
<P>
See also the following articles in the issue of Linux Gazette
indicated:
<BR>36: <EM>Introducing Samba</EM>
by John Blair
<BR>39: <EM>Expanding Your Home Network</EM>
by J.C. Pollman
<BR>44: <EM>DNS for the Home Network</EM>
by J.C. Pollman and Bill Mote
<BR>47: <EM>Backup for the Home Network</EM>
by J.C. Pollman and Bill Mote
<BR>48: <EM>SAMBA, Win95, NT and HP Jetdirect</EM>
by Eugene Blanchard
<BR>50: <EM>Sharing your Home</EM>
by J.C. Pollman and Bill Mote
<BR>57: <EM>Making a Simple Linux Network Including Windows 9x</EM>
by Juraj Sipos
<BR>61: <EM>Using ssh</EM>
by Matteo Dell'Omodarme
<BR>64: <EM>ssh suite: sftp, scp and ssh-agent</EM>
by Matteo Dell'Omodarme
<BR>67: <EM>Using ssh-agent for SSH1 and OpenSSH</EM>
by Jose Nazario
<BR>74: <EM>Play with the Lovely Netcat</EM>
by zhaoway
<P>
The Linux Gazette Answer Gang Knowledge Base under Network
Configuration has numerous relevant tidbits among which
<EM>Routing and Subnetting 101</EM> is mandatory reading.
<P>
And the Linux Focus Index by Subject under System Administration
has several articles well worth looking at, e.g.:
<BR><EM>Replacing a Windows/NT/2000 server using Linux and Samba</EM>
by Sebastian Sasias
<BR><EM>Through the Tunnel</EM>
by Georges Tarbouriech
<BR><EM>Samba Configuration</EM>
by Eric Seigne
<BR><EM>Network File System (NFS)</EM>
by Frederic Raynal
<BR><EM>Home Networking, glossary and overview</EM>
by Guido Socher
<H2>
9. A Future without Windows?
</H2>
<P>
Coming from pre-TRS-80 days, I've used DOS, various versions of
Windows, at least 3 releases of OS/2, Coherent, and now 5 releases
of SuSE Linux over at least 5 years. I am convinced that anyone
in a position to "compare and contrast" would agree that at best
Windows is unstable junk. One of my goals for quite some time
had been to gain complete independence from Windows.
<P>
But consider: our ISDN phone system has an RS-232 connector with
which it can be programmed via -- yeah, you got it. One of the
printers is USB for the notebook and guess whose drivers are
available. Our digital camera uses smart media and the USB smart
media reader... Oh, well, you get the picture.
<P>
I've only had Samba working for a week and actually hadn't even
intended to check it out but everything else worked so well that
it seemed worth a try. And it's so slick that I question whether
it would really be worth my effort to try to find replacement drivers
for this legacy stuff. How many hours, how many experiments, what
guarantee of success? Doesn't it make more sense to boot the
notebook under the "silly system" (I hope Monty Python put that
under GPL) and use the Samba connection to the rest of the network?
At least until the last Windows-legacy device eats it.
<!-- *** BEGIN author bio *** -->
<P>&nbsp;
<P>
<!-- *** BEGIN bio *** -->
<P>
<img ALIGN="LEFT" ALT="[BIO]" SRC="../gx/2002/note.png">
<em>
Edgar is a consultant in the Cologne/Bonn area in Germany.
His day job involves helping a customer with payroll, maintaining
ancient IBM Assembler programs, some occasional COBOL, and
otherwise using QMF, PL/1 and DB/2 under MVS.
</em>
<br CLEAR="all">
<!-- *** END bio *** -->
<!-- *** END author bio *** -->
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2003, Edgar Howell.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 87 of <i>Linux Gazette</i>, February 2003
</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">A Keep-Alive Program You Can Run Anywhere</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/jenkins.graham.html">Graham Jenkins</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<h2>The Poodle and the Labrador</h2>
<p>You are halfway through typing a new program into a remote machine connected
over a dial-up line, and you get
called to intervene in a fight between your partner's miniature poodle
and the neighbour's ugly yellow Labrador.
When you get back, your connection has timed-out.</p>
<p>Is this something that has happened to you?
Or perhaps you had to
drag your kids away from a particularly offensive episode of Jerry Springer,
then found you had to stick around to make sure they didn't come back?</p>
<h2>The Blonde Solution</h2>
<p>The traditional procedure for maintaining activity on your line during
an interruption of the type outlined above was to use a 'fortune' program
in a small loop so that a random saying got written to your screen
every half-minute. This could present some real problems if a person with
fair hair looked at your screen and saw something like:</p>
<pre>
Q: How do you make a blonde's eyes light up?
A: Shine a flashlight in her ear.
</pre>
<p>You could of course used a '-i' or equivalent parameter restricting 'fortune'
to generating inoffensive material like:</p>
<pre>
Computing Definition
Chaining - A method of attaching programmers to desk, to speed up output.
</pre>
<p>The more recent incarnations of the 'fortune' program offer their users
a more specific set of options. You can chose between offending
those who are Irish, gay or intellectually retarded!</p>
<h2>For The Terminally-Challenged</h2>
<p>If you are just using a browser to read your Hotmail messages, you probably
won't want to open a terminal window just so you can run a 'fortune'
program. If you are using an X11-compliant window-manager, you could start a
clock program with something like:</p>
<pre> xclock -digital -update 1 &</pre>
<p>But that's not going to work on your your vintage Windows 95 machine unless
you also happen to be running something like PC-Xware.</p>
<p>The 'KeepAlive.java' program listed here is designed to work anywhere.
It's written in Java 1.1 so that even the 'jview' virtual machine
on your basic Microsoft machine can handle it. It doesn't rely on finding
a 'fortune', 'xclock' or other program on a remote machine. And you don't
have to change anything when you connect via a different ISP.</p>
<h2>Finding A Partner</h2>
<p>But you have to send traffic somewhere, right? So how do you find a partner
machine which will receive your traffic? If we were writing this program as
a shell script, we might work out where our gateway was, and ping it at
appropriate intervals. That's not so easy to do in a Java program which might
run on any number of platforms. And in any case, it would be nice if we could
send traffic somewhere beyond the gateway machine.</p>
<p>In almost every sort of networking arrangement, the participating machines
have knowledge of one or more nameserver addresses. So what we can do from
our Java program is make periodic requests to those nameservers.
We need to ensure that any hosts whose addresses we request cannot be found
locally in a hosts table. And we need to also ensure that the answers to
our nameserver requests are not cached locally. If you take a look now at
the program, you will see that the names of the hosts whose addresses
we are requesting are generated by
examining the clock-time in milliseconds at the time of each request.
This results in names like A1040689223909, A1040689229448, etc.</p>
<p>That's really all we need to do. But it's nice to be able to see something
happening. So our program defines a 'MessageFrame' class which displays two
colored buttons in a GUI window. The colors of these are changed at each
iteration. We also set the title on the GUI window, and change it at each
iteration - so we can still see something happening when the window is
minimized. And we set up a listener to detect 'window closing' events and
perform a graceful shutdown.</p>
<h2>Getting It Together</h2>
<p>Here's the
<a href="misc/jenkins/KeepAlive.java.txt">program</a>.
You need to compile it with a command like:
<pre> javac KeepAlive.java</pre>
This will generate three 'class' files which contain code which can be executed
on a java virtual machine. So you can copy those class files to a directory
on another machine, then execute it with a command like:
<pre> java KeepAlive</pre>
To use the Microsoft virtual machine on a Windows box, use:
<pre> java KeepAlive</pre>
</p>
<pre>
/* @(#) KeepAlive.java Trivial keep-alive program. Tries at 5-second intervals
* to find addresses for hosts with generated names. This
* ensures that messages are sent to nameserver(s).
* Copyright (c) 2002 Graham Jenkins &lt;grahjenk@au1.ibm.com&gt;
* All rights reserved. Version 1.06, August 15, 2002.
*/
import java.io.*;
import java.net.*;
import java.awt.*;
import java.awt.event.*;
import java.util.Date;
public class KeepAlive {
public static void main(String[] args) {
MessageFrame f=new MessageFrame(); // Change button colours each iteration.
int flag=0; // Also switch frame-title so we can see
while ( true ) { // activity whilst iconified.
f.statusMess(Color.red,Color.red); f.setTitle("==X==");
try {InetAddress addr=InetAddress.getByName("A"+(new Date()).getTime());}
catch (UnknownHostException ioe) {}
if(flag==0) {f.statusMess(Color.yellow,Color.green); f.setTitle("1.06");}
else {f.statusMess(Color.green,Color.yellow); f.setTitle("KeepAlive");}
flag=1-flag;
try {Thread.sleep(5000L);} catch (InterruptedException e) {}
}
}
}
class MessageFrame extends Frame implements ActionListener {
private Button b1, b2; // Displays two coloured buttons.
public MessageFrame() {
Panel p=new Panel(); p.setLayout(new FlowLayout());
b1=new Button() ; b2=new Button(); p.add(b1); p.add(b2);
this.add("South",p); this.setSize(150,50); this.show();
this.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) { System.exit(0); }
});
}
public void statusMess(Color left, Color right) {
b1.setBackground(left); b2.setBackground(right);
}
public void actionPerformed(ActionEvent e) {}
}
</pre>
<p>If you have Java 1.1 or later, and no requirement to use the Microsoft
virtual machine,
you can assemble the class files into a single 'jar' file, then execute it
using the '-jar' option thus:
<pre>
echo "Main-Class: KeepAlive\015" &gt;/tmp/MyManifest
jar cmf /tmp/MyManifest /tmp/KeepAlive.jar *.class
java -jar /tmp/KeepAlive.jar
</pre>
<h2>If You Don't Have It</h2>
<p>If your machine doesn't have Java, you can get it from
<a href="http://java.sun.com/j2se/downloads.html">Sun MicroSystems</a>.
And if you need to know more about network programming with Java, you
could take a look at <a href="http://www.davidreilly.com/jnpbook">"Java Network
Programming and Distributed Computing" by David Reilly and Michael Reilly</a>.
</p>
<!-- *** BEGIN author bio *** -->
<P>&nbsp;
<P>
<!-- *** BEGIN bio *** -->
<P>
<img ALIGN="LEFT" ALT="[BIO]" SRC="../gx/2002/note.png">
<em>
Graham is a Unix Specialist at IBM Global Services, Australia. He lives
in Melbourne and has
built and managed many flavors of proprietary and open systems on several
hardware platforms.
</em>
<br CLEAR="all">
<!-- *** END bio *** -->
<!-- *** END author bio *** -->
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2003, Graham Jenkins.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 87 of <i>Linux Gazette</i>, February 2003
</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">Linux-Based Voice Recognition</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/lodato.html">Janine M Lodato</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<P> Let's look at Linux-based voice recognition software from the perspective of China.
It would behoove Linux computer makers anyway to begin manufacturing their
computers in China, because China offers a low-cost method of manufacturing and
provides them with a large market for their hardware which can also be exported
to other important markets around the world.
<P> Linux computers have the capacity to accommodate voice recognition
systems, such as IBM ViaVoice. This is especially advantageous to Chinese
speakers because both Mandarin and Cantonese are very complex in the written
form, so documents could be more easily produced through voice recognition
software running on a Linux platform. Using a keyboard is next to impossible
for Chinese languages because so many characters are involved in typing a
document.
<P> Other languages will also benefit from using voice recognition software
for purposes of speed. Hands-busy, eyes-busy professionals can benefit
greatly from voice recognition so they don't have to use a mouse and keyboard
to document their findings. Voice-activated, easily-used telephone systems
will benefit all walks of life. Anyone driving a car will find voice
recognition a much more effective way of manipulating a vehicle and
communicating from the vehicle.
<P> The health-care market alone may justify the Linux based voice
recognition project. Health-care services are the largest expense of the
Group of Ten nations, and it is the fastest growing sector as well.
Health-care workers would benefit from using their voices to document
describing the treatments of patients. Voice recognition allows them a
hands-free environment in which to analyze, treat and write about particular
cases easily and quickly.
<P> Electronically connected medical devices via wireless
LAN can benefit:
<UL>
<LI> ...Hospital administration staff
<UL>
<LI> Improve the usage efficiency of resources
<LI> Achieve standardized, quality patient management
<LI> Dramatically reduce data recording (transcription) errors
<LI> Lower costs
<LI> Make any room a telemetry room on demand (that is, do laboratory
measurements in any room regardless of where the central equipment is located)
</UL>
<LI> ...Medical staff
<UL>
<LI> Be empowered with a 24/7 complete set of vital-sign data
<LI> Have more time for hands-on care
<LI> See changes in patient status immediately to enable quicker responses
</UL>
</UL>
<P> In this life sciences field, the simplicity, reliability and low cost of
Linux for servers, tablets, embedded devices and desktops is paramount.
Only about 10% of the documents in the health-care field in the USA are
produced electronically due to the cumbersome and unreliable nature of the
Windows environment. 30% of the cost of health-care is a direct result of
manual creation of the documents and many of the malpractice cases are also
due to the imprecision of transcriptions of manually scribbled medical
records and directives, as anybody who looks at a prescription can attest.
<P> Obviously, the market for these new technologies exists. What remains
is for a hungry company with aggressive sales people to tap into that market.
Once those sales people get the technology distributed, the needs of many
will be met and a new mass market will open up that Microsoft isn't filling:
assistive technology (AT). Actually, the field already exists but needs to
be expanded to include both physically disabled and functionally disabled.
<P> Yes, voice recognition offers great promise for the future. However, it
isn't perfect and needs to be improved. One improvement could use lip
reading to bolster its accuracy.
Still another is multi-tonal voice input. Another is directional
microphones. Every generation of voice recognition software will improve as
the hardware for Linux gets bigger and stronger.
<!-- *** BEGIN author bio *** -->
<P>&nbsp;
<P>
<!-- *** BEGIN bio *** -->
<P>
<img ALIGN="LEFT" ALT="[BIO]" SRC="../gx/2002/note.png">
<em>
</em>
<br CLEAR="all">
<!-- *** END bio *** -->
<!-- *** END author bio *** -->
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2003, Janine M Lodato.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 87 of <i>Linux Gazette</i>, February 2003
</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 Adventure of the Arbitrary Archives</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/okopnik.html">Ben Okopnik</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<p>Spring was in full bloom, and Woomert Foonly was enjoying another perfect
day. It had featured a trivially easy configuration of a 1,000-node Linux
cluster, and had been brought to an acme by lunching on Moroccan
<i>b'stila</i>
with just a touch of <i>ras el hanout</i> curry and a fruited <i>couscous</i>
on the side, complemented by a dessert of sweet rice with cinnamon. All
was at peace... until Frink Ooblick burst in, supporting - almost carrying
- a man who seemed to be in the last extremity of shock. Frink helped him
to the couch, then dropped into the easy chair, clearly exhausted by his
effort.
<p>&nbsp;-- "Woomert, it's simply scandalous. This is Resolv Dot Conf, a humble...
erm, well, a sysadmin, anyway. Recently, he was cruelly forced to install
some kind of a legacy OS on his manager's computer - can you imagine? -
and now, he's being asked to do something that sounds nearly impossible,
although I could only get scant details. He had heard of your reputation
(who hasn't, these days?), and was coming to see if you could help him,
but collapsed in the street just outside your door due to the residual
shock and a severe Jolt Cola deficiency. As to the problem... well, I'll
let him tell you."
<p>Woomert had been tending to their guest while listening, with the result
that the latter now looked almost normal. Indeed, Woomert's "sysadmin-grade
coffee" was well-known among the <i>cognoscenti</i> for its restorative
powers, although the exact recipe (it was thought to have Espresso Alexander
and coffee ice cream somewhere in its ancestry, but the various theories
diverged widely after that point) remained a deep secret.
<p>Now, though, the famous detective's eyes sharpened to that look of concentration
he habitually wore while working.
<p>&nbsp;-- "Please state your problem clearly and concisely."
<p>The quickly recovering sysadmin shook his head mournfully.
<p>&nbsp;-- "Well, Mr. Foonly... you see, what I have is a script that processes
the data submitted to us by our satellite offices. The thing is, it all
comes in various forms: we're a health insurance data processor, and every
company's format is different. Not only that, but the way everyone submits
the data is different: some just send us a plain data file, others use
'gzip', or 'compress', or 'bzip', or 'rar', or even 'tar' <i>and</i>
'compress' (or 'gzip'), and others - fortunately, all of those are just
plain data - hand us a live data stream out of their proprietary
applications. Our programmers handled the various format conversions as
soon as they got the specs, but this arbitrary compression problem was left
up to me, and it's got me up a tree!"
<p>He stopped to take a deep breath and another gulp of Woomert's coffee,
which seemed to revive him further, although he still sat hunched over,
his forehead resting on his hand.
<p>"Anyway, at this point, making it all work still requires human intervention;
we've got two people doing nothing but sorting and decompressing the files,
all day long. If it wasn't for that, the whole system could be completely
automated... and of course, management keeps at me: 'Why isn't it fixed
yet? Aren't you computer people supposed to...' and so on."
<p>When he finally sat up and looked at Woomert, his jaw was firmly set.
He was a man clearly resigned to his fate, no matter how horrible.
<p>"Be honest with me, Mr. Foonly. Is there a possibility of a solution,
or am I finished? I know The Mantra <a href="#1">[1]</a>, of course, but
I'd like to go on if possible; my users need me, and I know of The Dark
Powers that slaver to descend upon their innocent souls without a sysadmin
to protect them."
<p>Woomert nodded, recognizing the weary old warrior's words as completely
true; he, too, had encountered and battled The Dark Ones, creatures that
would completely unhinge the minds of the users if they were freed for
even a moment, and knew of the valiant SysAdmin's Guild
(<a href="http://sage.org">http://sage.org</a>) which had sworn
to protect the innocent (even though it was often protection
from themselves, via the application of the mystic and holy LART <a href="#2">[2]</a>).
<p>&nbsp;-- "Resolv, I'm very happy to say that there is indeed a solution to
the problem. I'm sure that you've done your research on the available tools,
and have heard of '<tt>atool</tt>', an archive manager by Oskar Liljeblad..."
<p>At Resolv's nod, he went on.
<p>"All right; then you also know that it will handle all of the above
archive formats and more. Despite the fact that it's written in Perl, we're
not going to use any of its code in your script - that would be a wasteful
duplication of effort. Instead, we're simply going to use '<tt>acat'</tt>,
one of <tt>'atool'</tt>s utilities, as an external filter - a conditional
one. All we have to do is insert it right at the beginning of your script,
like so:
<pre>
<hr WIDTH="100%">#!/usr/bin/perl -w
# Created by Resolv Dot Conf on Pungenday, Chaos 43, 3166 YOLD
<b>@ARGV = map { /\.(gz|tgz|zip|bz2|rar|Z)$/ ? "acat $_ '*' 2>/dev/null|" : $_ } @ARGV;
</b># Rest of script follows</pre>
<pre>...
<hr WIDTH="100%"></pre>
"Perl will take care of the appropriate magic - and that will take care
of the problem."
<p>The sysadmin was on his feet in a moment, fervently shaking Woomert's
hand.
<p>&nbsp;-- "Mr. Foonly, I don't know how to thank you. You've saved... well,
I won't speak of that, but I want you to know that you've always got a
friend wherever I happen to be. Wait until they see <i>this</i>!... Uh,
just to make sure I understand - what <b>is</b> it? How does it work?"
<p>Woomert glanced over at Frink, who also seemed to be on the edge of
his seat, eager for the explanation.
<p>&nbsp;-- "What do you think, Frink - can you handle this one? I've only used
one function and one operator; the rest of it happened automagically, simply
because of the way that Perl deals with files on the command line."
<p>Frink turned a little pink, and chewed his thumb as he always did when
he was nervous.
<p>&nbsp;-- "Well, Woomert... I know you told me to study the 'map' function,
but it was pretty deep; I got lost early on, and then there was this new
movie out..."
<p>Woomert smiled and shook his head.
<p>&nbsp;-- "All right, then. 'map', as per the info from '<tt>perldoc -f map</tt>',
evaluates the specified expression or block of expressions for each element
of a list - sort of like a 'for' loop, but much shorter and more convenient
in many cases. I also used the ternary conditional operator ('<tt>?:</tt>')
which works somewhat like an "if-then-else" construct:
<pre>
<hr WIDTH="100%"># Ternary conditional op - sets $a to 5 if $b is true, to 10 otherwise
$a = $b ? 5 : 10;
# "if-then-else" construct - same action
if ( $b ){
$a = 5;
}
else {
$a = 10;
}
<hr WIDTH="100%"></pre>
"Both of the above do the same thing, but again, the first method is shorter
and often more convenient. Examining the script one step at a time, what
I have done is test each of the elements in @ARGV, which initially contains
everything on the command line that follows the script name, against the
following regular expression:
<p><tt>/\.(gz|tgz|zip|bz2|rar|Z)$/</tt>
<p>This will match any filename that ends in a period (a literal dot) followed
by any of the specified extensions.
<p>Now, if the filename <i>doesn't</i> match the regex, the ternary
operator returns the part after the colon, '<tt>$_</tt>' - which simply
contains the original filename. Perl then processes the filename as it
normally does the ones contained in @ARGV: it opens a filehandle to that
file and makes its contents available within the script. In fact, there
are a number of ways to access the data once that's done; read up on the
diamond operator ('<tt>&lt;&gt;</tt>') , the STDIN filehandle, and the ARGV
filehandle (note the similarity <i>and</i> the difference, Frink!) for
information on some of the many available methods of doing file I/O in
Perl."
<p>"On the other hand, if the current element <i>does</i> match, the ternary
operator will return the code before the colon, in this case<b></b>
<p><tt>"acat $_ '*' 2&gt;/dev/null|"</tt>
<p>Perl will then execute the above command for the current filename. The
syntax may seem a little odd, but it's what '<tt>acat</tt>' (or, more to
the point, the archive utilities that it uses) requires to process the
files and ignore the error messages. Note that the command ends in '|',
the pipe symbol; what happens here is much like doing a pipe within the
shell. The command will be executed, the output will be placed in a memory
buffer, and the contents of that buffer will become available on the filehandle
that Perl would normally have opened for that file - presto, pure magic!
<a href="#3">[3]</a>"
<p>"So, to break it all out in long form, here's what I did:
<pre>
<hr WIDTH="100%">@ARGV =
map { # Use the BLOCK syntax of 'map'
if ( /\.(gz|tgz|zip|bz2|rar|Z)$/ ){ # Look for archive extensions
"acat $_ '*' 2&gt;/dev/null|"; # Uncompress/pipe out the contents
}
else {
$_; # Otherwise, return original name
}
} @ARGV; # This is the list to "walk" over
<hr WIDTH="100%"></pre>
"Perl handles it from that point on. Once you pass it something useful
on the command line or standard input, it knows just what to do. In fact,"
he glanced sternly over at Frink, who once again looked abashed,
"studying '<tt>perldoc perlopentut</tt>' is something I recommend to anyone
who wants to understand how Perl does I/O. This includes files, pipes,
forking child processes, building filters, dealing with binary files, duplicating
file handles, the single-argument version of 'open', and many other things.
In some ways, this could be called the most important document that comes
with Perl. Taking a look at '<tt>perldoc perlipc</tt>' as a follow-up would
be a good idea as well - it deals with a number of related issues, including
opening safe (low privilege) pipes to possibly insecure processes, something
that can become very important in a hurry."
<p>&nbsp;-- "Now, Resolv, I believe that you have a bright new future stretching
out ahead of you; your problem will be solved, your management will be
pleased, and your users will remain safe from Those Outside The Pale. If
you would care to join us in a little celebration, I've just finished boiling
a Spotted Dog, and - oh. Where did he go?... It's a very fine English pudding
with currants, after all. Well, I suppose he wanted to implement that change
as soon as possible..."
<hr WIDTH="100%">
<H3>Footnotes</H3>
<p><a NAME="1"></a>[1] "Down, Not Across." For those who need additional
clues on the grim meaning of The Sysadmin Mantra, search the archives of
<b>alt.sysadmin.recovery</b>
at <a href="http://groups.google.com">&lt;http://groups.google.com&gt;</a>,
and all will become clear. If it does not, then you weren't meant to know.
:)
<p><a NAME="2"></a>[2] From The Jargon File:
<pre> Luser Attitude Readjustment Tool. ... The LART classic is a 2x4 or
other large billet of wood usable as a club, to be applied upside the
head of spammers and other people who cause sysadmins more grief than
just naturally goes with the job. Perennial debates rage on
alt.sysadmin.recovery over what constitutes the truly effective LART;
knobkerries, semiautomatic weapons, flamethrowers, and tactical nukes
all have their partisans. Compare {clue-by-four}.</pre>
<p><br><a NAME="3"></a>[3] See "perldoc perlopentut" for a tutorial on
opening files, the 'magic' in @ARGV, and even "Dispelling the Dweomer"
for those who have seen too much magic already. :)
<!-- *** BEGIN author bio *** -->
<P>&nbsp;
<P>
<P> Ben is a Contributing Editor for Linux Gazette and a member of
The Answer Gang.
<!-- *** BEGIN bio *** -->
<P>
<IMG ALT="picture" SRC="../../gx/2002/tagbio/ben-okopnik.jpg" WIDTH="199"
HEIGHT="200" ALIGN="left" HSPACE="10" VSPACE="10">
<em>
Ben was born in Moscow, Russia in 1962. He became interested in
electricity at age six--promptly demonstrating it by sticking a fork into
a socket and starting a fire--and has been falling down technological mineshafts
ever since. He has been working with computers since the Elder Days, when
they had to be built by soldering parts onto printed circuit boards and
programs had to fit into 4k of memory. He would gladly pay good money to any
psychologist who can cure him of the resulting nightmares.
<p>Ben's subsequent experiences include creating software in nearly a dozen
languages, network and database maintenance during the approach of a hurricane,
and writing articles for publications ranging from sailing magazines to
technological journals. Having recently completed a seven-year
Atlantic/Caribbean cruise under sail, he is currently docked in Baltimore, MD,
where he works as a technical instructor for Sun Microsystems.
<p>Ben has been working with Linux since 1997, and credits it with his complete
loss of interest in waging nuclear warfare on parts of the Pacific Northwest.
</em>
<br CLEAR="all">
<!-- *** END bio *** -->
<!-- *** END author bio *** -->
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2003, Ben Okopnik.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 87 of <i>Linux Gazette</i>, February 2003
</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">Fun with Simputer and Embedded Linux</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/pramode.html">Pramode C.E</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<html>
<head><title>Fun with Simputer and Embedded Linux</title></head>
<h1>Fun with Simputer and Embedded Linux</h1>
The Simputer is a StrongArm CPU based handheld device running
Linux. Originally developed by professors at the Indian
Institute of Science, Bangalore, the device has a social
objective of bringing computing and connectivity within
the reach of rural communities. This articles provides a
tutorial introduction to programming the Simputer (and similar
ARM based handheld devices - there are lots of them in the
market). The reader is expected to have some experience
programming on Linux. Disclaimer: I try to describe things
which I had done on my Simputer without any problem - if
following my instructions leads to your handheld going up
in smoke - I should not be held responsible!
<h2>Hardware/Software</h2>
<p>
The device is powered by an Intel StrongArm (SA-1110) CPU.
The flash memory size is either 32Mb or 16Mb and RAM is
64Mb or 32Mb. The peripheral features include:
<p>
<ol>
<li> USB master as well as slave ports.
<li> Standard serial port.
<li> Infra Red communication port.
<li> Smart card reader
</ol>
<p>
Some of these features are enabled by using a `docking cradle'
provided with the base unit. Power can be provided either
by rechargeable batteries or external AC mains.
<p>
Simputer is powered by GNU/Linux - kernel version 2.4.18
(with a few patches) works fine. The unit comes bundled
with binaries for the X-Window system and a few simple utility
programs. More details can be obtained from the project
home page at <a href="http://www.simputer.org">www.simputer.org</a>.
<h2> Powering up </h2>
<p>
There is nothing much to it, other than pressing the `power
button'. You will see a small tux picture coming up and
within a few seconds, you will have X up and running . The
LCD screen is touch sensitive and you can use a small `stylus'
(geeks use finger nails!) to select applications and move
through the graphical interface. If you want to have keyboard
input, be prepared for some agonizing manipulations using
the stylus and a `soft keyboard' which is nothing but a
GUI program from which you can select single alphabets and
other symbols.
<h2> Waiting for bash </h2>
<p>
GUI's are for kids. You are not satisfied till you see the
trusted old bash prompt. Well, you don't have to try a lot.
The Simputer has a serial port - attach the provided serial
cable to it - the other end goes to a free port on your
host Linux PC (in my case, /dev/ttyS1).
Now fire up a communication program (I use `minicom') -
you have to first configure the program so that it uses
/dev/ttyS1 with communication speed set to 115200 (that's
what the Simputer manual says - if you are using a similar
handheld, this need not be the same) and 8N1 format, hardware
and software flow controls disabled. Doing this with minicom
is very simple - invoke it as:
<p>
minicom -m -s
<p>
Once configuration is over - just type:
<p>
minicom -m
<p>
and be ready for the surprise. You will immediately see a
login prompt. You should be able to type in a user name/password
and log on. You should be able to run simple commands like
`ls', `ps' etc - you may even be able to use `vi' .
<p>
If you are not familiar with running communication programs
on Linux, you may be wondering what really happened. Nothing
much - it's standard Unix magic. A program sits on the Simputer
watching the serial port (the Simputer serial port, called
ttySA0) - when you run minicom on the Linux PC, you establish
a connection with that program, which sends you a login
prompt over the line, reads in your response, authenticates
you and spawns a shell with which you can interact over
the line.
<p>
Once minicom initializes the serial port on the PC end, you
can `script' your interactions with the Simputer. You are
exploiting the idea that the program running on the Simputer
is watching for data over the serial line - the program
does not care whether the data comes from minicom itself
or a script. You can try out the following experiment:
<p>
<ol>
<li> Open two consoles (on the Linux PC)
<li> Run minicom on one console, log on to the simputer
<li> On the other console, type `echo ls &gt; /dev/ttyS1'
<li> Come to the first console - you will see that the command
`ls' has executed on the Simputer.
</ol>
<h2> Setting up USB Networking </h2>
<p>
The Simputer comes with a USB slave port. You can establish
a TCP/IP link between your Linux PC and the Simputer via
this USB interface. Here are the steps you should take:
<p>
<ol>
<li> Make sure you have a recent Linux distribution - Red Hat
7.3 is good enough.
<li> Plug one end of the USB cable onto the USB slave slot in
the Simputer, then boot the Simputer.
<li> Boot your Linux PC. DO NOT connect the other end of the
USB cable to your PC now. Log in as root on the PC.
<li> Run the command `insmod usbnet' to load a kernel module
which enables USB networking on the Linux PC. Verify that
the module has been loaded by running `lsmod'.
<li> Now plug the other end of the USB cable onto a free USB
slot of the Linux PC. The USB subsystem in the Linux kernel
should be able to register a device attach. On my Linux
PC, immediately after plugging in the USB cable, I get
the following kernel messages (which can be seen by running
the command `dmesg'):
</ol>
<pre>
usb.c: registered new driver usbnet
hub.c: USB new device connect on bus1/1, assigned device
number 3
usb.c: ignoring set_interface for dev 3, iface 0, alt 0
usb0: register usbnet 001/003, Linux Device
</pre>
<p>
After you have reached this far, you have to run a few more
commands:
<p>
<ol>
<li> Run `ifconfig usb0 192.9.200.1' - this will assign an IP
address to the USB interface on the Linux PC.
<li> Using `minicom' and the supplied serial cable, log on to
the Simputer as root. Then run the command `ifconfig usbf
192.9.200.2' on the Simputer.
<li> Try `ping 192.9.200.2' on the Linux PC. If you see ping
packets running to and fro, congrats. You have successfully
set up a TCP/IP link!
</ol>
You can now telnet/ftp to the Simputer through this TCP/IP
link.
<h2> Hello, Simputer </h2>
<p>
It's now time to start real work. Your C compiler (gcc) normally
generates `native' code, ie, code which runs on the microprocessor
on which gcc itself runs - most often, an Intel (or clone)
CPU. If you wish your program to run on the Simputer (which
is based on the StrongArm microprocessor), the machine code
generated by gcc should be understandable to the StrongArm
CPU - your `gcc' should be a cross compiler. If you download
the gcc source code (preferably 2.95.2) together with `binutils',
you should be able to configure and compile it in such a
way that you get a cross compiler (which could be invoked
like, say, arm-linux-gcc). This might be a bit tricky if
you are doing it for the first time - your handheld vendor
should supply you with a CD which contains the required
tools in a precompiled form - it is recommended that you
use it (but if you are seriously into embedded development,
you should try downloading the tools and building them yourselves).
<p>
Assuming that you have arm-linux-gcc up and running, you
can write a simple `Hello, Simputer' program, compile it
into an `a.out', ftp it onto the Simputer and execute it
(it would be good to have one console on your Linux PC running
ftp and another one running telnet - as soon as you compile
the code, you can upload it and run it from the telnet console
- note that you may have to give execute permission to the
ftp'd code by doing `chmod u+x a.out' on the Simputer).
<h2> A note on the Arm Linux kernel </h2>
<p>
The Linux kernel is highly portable - all machine dependencies
are isolated in directories under the `arch' subdirectory
(which is directly under the root of the kernel source tree,
say, /usr/src/linux). You will find a directory called `arm'
under `arch'. It is this directory which contains ARM CPU
specific code for the Linux kernel.
<p>
The Linux ARM port was initiated by Russell King. The ARM
architecture is very popular in the embedded world and there
are a LOT of different machines with fantastic names like
Itsy, Assabet, Lart, Shannon etc all of which use the StrongArm
CPU (there also seem to be other kinds of ARM CPU's - now
that makes up a really heady mix). There are minor differences
in the architecture of these machines which makes it necessary
to perform `machine specific tweaks' to get the kernel working
on each one of them. The tweaks for most machines are available
in the standard kernel itself, and you only have to choose
the actual machine type during the kernel configuration
phase to get everything in order. But to make things a bit
confusing with the Simputer, it seems that the tweaks for
the initial Simputer specification have got into the ARM
kernel code - but the vendors who are actually manufacturing
and marketing the device seem to be building according to
a modified specification - and the patches required for
making the ARM kernel run on these modified configurations
is not yet integrated into the main kernel tree. But that
is not really a problem, because your vendor will supply
you with the patches - and they might soon get into the
official kernel.
<h2> Getting and building the kernel source </h2>
<p>
You can download the 2.4.18 kernel source from the nearest
Linux kernel ftp mirror. You will need the file `patch-2.4.18-rmk4'
(which can be obtained from the ARM Linux FTP site ftp.arm.linux.org.uk).
You might also need a vendor supplied patch, say, `patch-2.4.18-rmk4-vendorstring'.
Assume that all these files are copied to the /usr/local/src
directory.
<p>
<ol>
<li> First, untar the main kernel distribution by running `tar
xvfz kernel-2.4.18.tar.gz'
<li> You will get a directory called `linux'. Change over to
that directory and run `patch -p1 &lt; ../patch-2.4.18-rmk4'.
<li> Now apply the vendor supplied patch.
Run `patch -p1 &lt; ../patch-2.4.18-rmk4-vendorstring'.
</ol>
<p>
Now, your kernel is ready to be configured and built. Before
that, you have to examine the top level Makefile (under
/usr/local/src/linux) and make two changes - there will
be a line of the form:
<p>
ARCH := &lt;lots-of-stuff&gt;
<p>
near the top. Change it to
<p>
ARCH := arm
<p>
You need to make one more change. You observe that the Makefile
defines:
<p>
<pre>
AS = ($CROSS_COMPILE)as
LD = ($CROSS_COMPILE)ld
CC = ($CROSS_COMPILE)gcc
</pre>
<p>
You note that the symbol CROSS_COMPILE is equated with the
empty string. During normal compilation, this will result
in AS getting defined to `as', CC getting defined to `gcc'
and so on which is what we want. But when we are cross compiling,
we use arm-linux-gcc, arm-linux-ld, arm-linux-as etc. So
you have to equate CROSS_COMPILE with the string arm-linux-,
ie, in the Makefile, you have to enter:
<p>
CROSS_COMPILE = arm-linux-
<p>
<p>
Once these changes are incorporated into the Makefile, you
can start configuring the kernel by running `make menuconfig'
(note that it is possible to do without modifying the Makefile.
You run `make menuconfig ARCH=arm'). It may take a bit of
tweaking here and there before you can actually build the
kernel without error. You will not need to modify most things
- the defaults should be acceptable.
<p>
<ol>
<li> You have to set the system type to SA1100 based ARM system
and then choose the SA11x0 implementation to be `Simputer(Clr)'
(or something else, depending on your machine). I had
also enabled SA1100 USB function support, SA11x0 USB net
link support and SA11x0 USB char device emulation.
<li> Under Character devices-&gt;Serial drivers, I enabled SA1100
serial port support, console on serial port support and
set the default baud rate to 115200 (you may need to set
differently for your machine).
<li> Under Character devices, SA1100 real time clock and Simputer
real time clock are enabled.
<li> Under Console drivers, VGA Text console is disabled.
<li> Under General Setup, the default kernel command string
is set to `root=/dev/mtdblock2 quite'. This may be different
for your machine.
</ol>
<p>
Once the configuration process is over, you can run
<p>
make zImage
<p>
and in a few minutes, you should get a file called `zImage'
under arch/arm/boot. This is your new kernel.
<h2> Running the new kernel </h2>
<p>
I describe the easiest way to get the new kernel up and running.
<p>
Just like you have LILO or Grub acting as the boot loader
for your Linux PC, the handheld too will be having a bootloader
stored in its non volatile memory. In the case of the Simputer,
this bootloader is called `blob' (which I assume is the
boot loader developed for the Linux Advanced Radio Terminal
Project, `Lart'). As soon as you power on the machine, the
boot loader starts running - If you start minicom on your
Linux PC, keep the `enter' key pressed and then power on
the device, the bootloader, instead of continuing with booting
the kernel stored in the device's flash memory, will start
interacting with you through a prompt which looks like this:
<p>
blob&gt;
<p>
At the bootloader prompt, you can type:
<p>
blob&gt; download kernel
<p>
which results in blob waiting for you to send a uuencoded
kernel image through the serial port. Now, on the Linux
PC, you should run the command:
<p>
uuencode zImage /dev/stdout &gt; /dev/ttyS1
<p>
This will send out a uuencoded kernel image through the COM
port - which will be read and stored by the bootloader in
the device's RAM. Once this process is over, you get back
the boot loader prompt. You just have to type:
<p>
blob&gt; boot
<p>
and the boot loader will run the kernel which you have right
now compiled and downloaded.
<h2> A bit of kernel hacking </h2>
<p>
What good is a cool new device if you can't do a bit of kernel
hacking? My next step after compiling and running a new
kernel was to check out how to compile and run kernel modules.
Here is a simple program called `a.c':
<p>
<pre>
#include &lt;linux/module.h&gt;
#include &lt;linux/init.h&gt;
/* Just a simple module */
int
init_module(void)
{
printk("loading module...\n");
return 0;
}
void
cleanup_module(void)
{
printk("cleaning up ...\n");
}
</pre>
<p>
You have to compile it using the command line:
<p>
arm-linux-gcc -c -O -DMODULE -D__KERNEL__ a.c -I/usr/local/src/linux-2.4.18/include
<p>
You can ftp the resulting `a.o' onto the Simputer and load
it into the kernel by running:
<p>
insmod ./a.o
<p>
You can remove the module by running:
<p>
rmmod a
<p>
<h2> Handling Interrupts </h2>
<p>
After running the above program, I started scanning the kernel
source to identify the simplest code segment which would
demonstrate some kind of physical hardware access - and
I found it in the hard key driver. The Simputer has small
buttons which when pressed act as the arrow keys - these
buttons seem to be wired onto the general purpose I/O pins
of the ARM CPU (which can also be configured to act as interrupt
sources - if my memory of reading the StrongArm manual is
correct). Writing a kernel module which responds when these
keys are pressed is a very simple thing - here is a small
program which is just a modified and trimmed down version
of the hardkey driver - you press the button corresponding
to the right arrow key - an interrupt gets generated which
results in the handler getting executed. Our handler simply
prints a message and does nothing else. Before inserting
the module, we must make sure that the kernel running on
the device does not incorporate the default button driver
code - checking /proc/interrupts would be sufficient.
<p>
Compile the program shown below into an object file (just
as we did in the previous program), load it using `insmod',
check /proc/interrupts to verify that the interrupt line
has been acquired. Pressing the button should result in the
handler getting called - the interrupt count displayed in
/proc/interrupts should also change.
<pre>
#include &lt;linux/module.h&gt;
#include &lt;linux/ioport.h&gt;
#include &lt;linux/sched.h&gt;
#include &lt;asm-arm/irq.h&gt;
#include &lt;asm/io.h&gt;
static void
key_handler(int irq, void *dev_id, struct pt_regs *regs)
{
printk("IRQ %d called\n", irq);
}
static int
init_module(void)
{
unsigned int res = 0;
printk("Hai, Key getting ready\n");
set_GPIO_IRQ_edge(GPIO_GPIO12, GPIO_FALLING_EDGE);
res = request_irq(IRQ_GPIO12, key_handler, SA_INTERRUPT,
"Right Arrow Key", NULL);
if(res) {
printk("Could Not Register irq %d\n", IRQ_GPIO12);
return res;
}
return res ;
}
static void
cleanup_module(void)
{
printk("cleanup called\n");
free_irq(IRQ_GPIO12, NULL);
}
</pre>
<h2> Future work </h2>
<p>
A Linux based handheld offers a lot of opportunities for
serious fun - as I learn more about the device, I shall try to
share my findings with the readers.
<h2> References </h2>
<p>
<ol>
<li> <a href="http://www.simputer.org">Simputer Project</a> Home Page.
<li> <a href="http://www.simputerland.com">Simputerland</a> and
<a href="http://www.picopeta.com">PicoPeta</a> - information
about Simputer development activities from companies which
are manufacturing and marketing the product.
<li> <a href="http://www.arm.linux.org.uk">Arm Linux</a> Project Home Page
<li> <a href="http://www.lart.tudelft.nl">Lart Project</a> Home Page. Lots
of cool stuff here. You might like to check out the `Clock
Scaling' link on this site. Clock scaling allows you to
change the clock speed of the running processor on the
fly - useful for saving battery power.
</ol>
<!-- *** BEGIN author bio *** -->
<P>&nbsp;
<P>
<!-- *** BEGIN bio *** -->
<P>
<img ALIGN="LEFT" ALT="[BIO]" SRC="../gx/2002/note.png">
<em>
I am an instructor working for IC Software in Kerala, India. I would have loved
becoming an organic chemist, but I do the second best thing possible, which is
play with Linux and teach programming!
</em>
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Copyright &copy; 2003, Pramode C.E.
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Published in Issue 87 of <i>Linux Gazette</i>, February 2003
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</TD><TD WIDTH="380">
<CENTER>
<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>
</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/qubism/qb-remastered.jpg">
<IMG ALT="[cartoon]" SRC="misc/qubism/qb-remastered.jpg"
WIDTH="640" HEIGHT="240"></A>
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<IMG ALT="[cartoon]" SRC="misc/qubism/qb-lotrdm.jpg"
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<BR CLEAR="all">
<P> All Qubism cartoons are
<A HREF="http://www.core.org.au/modules.php?name=Cartoons">here</A>
at the CORE web site.
<!-- *** BEGIN author bio *** -->
<P>&nbsp;
<P>
<!-- *** BEGIN bio *** -->
<P>
<img ALIGN="LEFT" ALT="[BIO]" SRC="../gx/2002/note.png">
<em>
Jon is the creator of the Qubism cartoon strip and current
Editor-in-Chief of the
<A HREF="http://www.core.org.au/">CORE</A> News Site.
Somewhere along the early stages of
his life he picked up a pencil and started drawing on the wallpaper. Now
his cartoons appear 5 days a week on-line, go figure. He confesses to
owning a Mac but swears it is for "personal use".
</em>
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<hr>
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Published in Issue 87 of <i>Linux Gazette</i>, February 2003
</STRONG></SMALL></CENTER>
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<CENTER>
<BIG><BIG><STRONG><FONT COLOR="maroon">Yacc/Bison - Parser Generators - Part 1</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/ramankutty.html">Hiran Ramankutty</A></STRONG>
</CENTER>
</TD></TR>
</TABLE>
<P>
<!-- END header -->
<h2><b>Introduction</b></h2>
<p>
<b>Yacc</b> ("Yet Another Compiler Compiler") is used to parse a language
described by a <b>context-free grammar</b>. Not all context-free languages can
be handled by Yacc or Bison and only those that are <b>LALR(1)</b> can be
parsed. To be specific, this means that it must be possible to tell how to
parse any portion of an input string with just a single token of look-ahead. I
will explain that clearly later in this article.
</p>
<p>
<b>Bison</b> is also a parser generator in the style of <b>Yacc</b>.
It was written primarily by Robert Corbett and Richard Stallman
made it Yacc compatible. There are differences between Bison and Yacc,
but that is not the purpose of this article.
</p>
<h2><b>Languages and Context-Free Grammars</b></h2>
<p>
Grammar can be associated with English language as a set of rules to
construct meaningful sentences. We can say the same for context-free
grammars. Almost all programming languages are based on context-free
grammars. The set of rules in any grammar will deal with syntactic
groupings that will help in the construction of semantic structures.
To be specific, it means that we specify one or more syntactic
groupings and give rules for constructing them from their parts. For
example in C: `expression' is one kind of grouping. One rule for making
an expression is, "An expression can be made of a minus sign and
another expression". Another would be, "An expression is an integer".
You must have noticed that the rules are recursive. In fact, every
such grammar must then have a rule which leads out of the recursion.
</p>
<p>
The most common formal system for representing such rules is the
<b>Backus-Naur Form</b> or "BNF". All BNF grammars are context-free
grammars.
</p>
<p>
In the grammatical rules for a language, we name a grouping as a symbol.
Those symbols which can be sub-divided into smaller constructs are
called non-terminals and those which cannot be subdivided are called
terminals. If a piece of input is a single terminal then it is called a
token and if it is a single nonterminal it is called a grouping. For
example: `identifier', `number', `string' are distinguished as tokens,
Whereas `expression', `statement', `declaration' and `function
definition' are groupings in C language. Now, the full grammar may use
additional language constructs with another set of nonterminal symbols.
</p>
<h2><b>Basic Parsing Techniques</b></h2>
<p>
A parser for grammar G determines whether an input string say `w' is a
sentence of G or not. If `w' is a sentence of G then the parser
produces the parse tree for `w' otherwise, an error message is
produced. By parse tree we mean a diagram that represents the syntactic
structure of a string `w'. There are two basic types of parsers for
context-free grammars - <b>bottom-up</b> and <b>top-down</b>, the former one
being of our interest.
</p>
<h3><b>Bottom-Up Parsing</b></h3>
<p>
It is also known as <b>Shift-Reduce Parsing</b>. Here, attempts to
construct a parse tree for an input begin at the leaves (bottom) and
work up towards the root (top). In other words this will lead to a
process of `reduction' of the input string to the start symbol of the
grammar based on its production rules. For example, consider the
grammar:
</p><p></p>
<pre>
<b><i>S -> aAcBe
A -> Ab/b
B -> d</i></b>
</pre>
<p></p>
<p>
Let w = "abbcde". Our aim is to reduce this string `w' to
<b><i>S</i></b>, where <b><i>S</i></b> is the start symbol. We scan
"abbcde" looking for substrings that match the right side of some
production. The substrings `b' and `d' qualify. Again there are 2 b's
to be considered. Let us proceed with leftmost `b'. We replace it by
`A' the left side of the production <b><i>A -> b</i></b>. The string
has now become "aAbcde". We now see that `Ab', `b' and `d' each match
the right side of some production. This time we will choose to replace
`Ab' by `A', the left side of the production <b><i>A -> Ab</i></b>.
The string now becomes "aAcde". Then replacing `d' by `B', the left
side of the production <b><i>B -> d</i></b>, we obtain "aAcBe". The
entire string can now be replaced by <b><i>S</i></b>.
</p>
<p>
Basically, we are replacing the right side of a production by the left
side the process being called a <i>reduction</i>. Quite easy! Not always. It
sometimes so happen that, the substring that we choose to reduce may produce
a string which is not decomposable to the start symbol <b><i>S</i></b>.
</p>
The substrings that are the right side of a production and when replaced
with the left side of that production in the input string that leads
eventually to the start symbol is called a <b>`handle'</b>. Now, the process
of bottom-up parsing may be viewed as one of finding and reducing `handles',
the reduction sequence being known as <b>`handle pruning'</b>.
</p>
<h4><b>Stack Implementation of Shift-Reduce Parsing</b></h4>
<p>
A convenient way to implement a shift-reduce parser is to use a stack and an
input buffer. Let `$' symbol mark the bottom of the stack and the right end
of the input.
</p>
<p>
The main concept is to shift the input symbols onto the stack until a
handle <font face=`Symbol'>b</font> is on top of the stack. Now we
reduce <font face=`Symbol'>b</font> to the left side of the appropriate
production. The parser repeats this cycle until it has detected an
error or until the stack contains the start symbol and the input is
empty:
</p>
<p>
In fact, there are four possible actions that a shift-reduce parser can
make and they are;
</p>
<p></p>
<ol>
<li>In a <i>shift</i> action, the next input symbol is shifted to the top of
the stack.
<li>In a <i>reduce</i> action, the parser knows that the right end of the
handle is at the top of the stack. It must then locate the left end of the
handle within the stack and decide with what nonterminal to replace the
handle.
<li>In an <i>accept</i> action, the parser announces successful completion
of parsing.
<li>In an <i>error</i> action, the parser discovers that a syntax error has
occurred and calls an error recovery routine.
</ol>
<p>
Let us see how these concepts are put into action in the example below.
</p>
<p>Consider the grammar below:</p>
<p></p>
<pre>
<b>E -> E + E
E -> E * E
E -> (E)
E -> id</b>
</pre>
<p>
Let the input string be
<b>id<sub>1</sub> + id<sub>2</sub> * id<sub>3</sub></b>
</p>
<P> <A HREF="misc/ramankutty/figure1.png">Figure 1</A> </P>
<h4><b>Constructing a Parse Tree</b></h4>
<p>
The bottom-up tree construction process has two aspects.
</p>
<ol>
<li>When we shift an input symbol <i>a</i> onto the stack we create a
one-node tree labeled <i>a</i>. Both the root and the yield of this tree
are <i>a</i>, and the yield truly represents the string of terminals
"reduced" (by zero reductions) to symbol <i>a</i>.
<li>When we reduce <i>X</i><sub>1</sub><i>X</i><sub>2</sub>...
<i>X</i><sub>n</sub> to <i>A</i>, we create a new node labeled <i>A</i>. Its
children, from left to right, are the roots of the trees for
<i>X</i><sub>1</sub>,<i>X</i><sub>2</sub>,...,<i>X</i><sub>n</sub>. If for
all i<sup>i</sup> the tree for <i>X</i><sub>i</sub> has yield
<i>x</i><sub>i</sub>, then the yield for the new tree is
<i>x</i><sub>1</sub><i>x</i><sub>2</sub>...<i>x</i><sub>n</sub>. This string
has in fact been reduced to <i>A</i> by a series of reductions culminating
in the present one. As a special case, if we reduce <i>E</i> to <i>A</i> we
create a node labeled <i>A</i> with one child labeled <i>E</i>.
</ol>
<h2><b>LR Parsing Algorithm</b></h2>
<p>
Construction of LALR parser requires the basic understanding of
constructing an LR parser. LR parser gets its name because it scans the
input from left-to-right and constructs a rightmost derivation in
reverse.
</p>
<p>
A parser generates a parsing table for a grammar. The parsing table
consists of two parts, a parsing action function <b>ACTION</b> and a
goto function <b>GOTO</b>.
</p>
<p>
An LR parser has an input, a stack, and a parsing table.
The input is read from left to right, one symbol at a time. The stack
contains a string of the form
s<sub>0</sub>X<sub>1</sub>s<sub>1</sub>...X<sub>m</sub>s<sub>m</sub>
where s<sub>m</sub> is on top. Each X<sub>i</sub> is a grammar symbol
and each s<sub>i</sub> is a symbol called a state. Each state symbol
summarizes the information contained in the stack below it and is used
to guide the shift-reduce decision.
</p>
<p>
The function <b>ACTION</b> stores values for s<sub>m</sub> that is
topmost stack element and a<sub>i</sub> that is the current input
symbol. The entry ACTION[s<sub>m</sub>, a<sub>i</sub>] can have one of
four values:
</p>
<ol>
<li>shift s
<li>reduce A -&gt; <font face="symbol">B</font>
<li>accept
<li>error
</ol>
<p>
The function <b>GOTO</b> takes a state and grammar symbol as arguments
and produces a state. Somewhat analogous to the transition table of a
deterministic finite automaton whose input symbols are the terminals
and nonterminals of the grammar.
</p>
<p>
A <i>configuration</i> of an LR parser is a pair whose first component
is the stack contents and whose second component is the unexpended
input:
</p>
<p align=center>
(s<sub>0</sub> X<sub>1</sub> s<sub>1</sub> . . . X<sub>m</sub> s<sub>m</sub>, a<sub>i</sub> a<sub>i+1</sub> . . . a<sub>n</sub>$) </p>
<p>
The next move of the parser is determined by reading a<sub>i</sub>, the
current input symbol, and s<sub>m</sub> the state on top of the stack,
and then consulting the action table entry
ACTION[s<sub>m</sub>, a<sub>i</sub>]. The four value mentioned above
for action table entry will produce four different configurations as
follows:
</p>
<p></p>
<ol>
<li> If ACTION[s<sub>m</sub>, a<sub>i</sub>] = shift s, the parser
executes a shift move, entering the configuration
<p align=center>
(s<sub>0</sub> X<sub>1</sub> s<sub>1</sub> . . . X<sub>m</sub> s<sub>m</sub> a<sub>i</sub> s, a<sub>i+1</sub> . . . a<sub>n</sub>$) </p>
Here the configuration has shifted the current input symbol
a<sub>i</sub> and the next state
s = GOTO[s<sub>m</sub>, a<sub>i</sub>] onto the stack;
a<sub>i+1</sub> becomes the new current input symbol.
<li>If ACTION[s<sub>m</sub>, a<sub>i</sub>] =
reduce A - &gt; <font face="symbol">B</font>,then the parser
executes a reduce a move, entering the configuration
<p align=center>
(s<sub>0</sub> X<sub>1</sub> s<sub>1</sub> . . . X<sub>m-r</sub> s<sub>m-r</sub> A s, a<sub>i</sub> a<sub>i+1</sub> . . . a<sub>n</sub>$) </p>
where s = GOTO[s<sub>m-r</sub>, A] and r is the length of
<font face="symbol">B</font>, the right side of the production.
Here the first popped 2r symbols off the stack (r state symbols and r
grammar symbols), exposing state s<sub>m-r</sub>. The parser then
pushed both A, the left side of the production, and s, the entry for
ACTION[s<sub>m-r</sub>, A], onto the stack. The current input symbol
is not changed in a reduce move. Specifically,
X<sub>m-r+1</sub> . . . X<sub>m</sub>, the sequence of grammar symbols
are popped off the stack and will always match
<font face="symbol">B</font>, the right side of the reducing
production.
<li> If ACTION[s<sub>m</sub>, a<sub>i</sub>] = accept, parsing is
completed.
<li> If ACTION[s<sub>m</sub>, a<sub>i</sub>] = error, the parser has
discovered an error and calls an error recovery routine.
</ol>
<p>
The LR parsing algorithm is simple. Initially the LR parser is in the
configuration
(s<sub>0</sub>, a<sub>1</sub>a<sub>2</sub>...a<sub>n</sub>$) where
s<sub>0</sub> is a designated intial state and
a<sub>1</sub>a<sub>2</sub>...a<sub>n</sub> is the string to be parsed.
Then the parser executes moves until an accept or error action is
encountered.
</p>
<p>
I mentioned earlier that the GOTO function is essentially the
transition table of a deterministic finite automaton whose input
symbols (terminals and nonterminals) and a state when taken as
arguments produce another state. Hence the GOTO function can be
represented by a graph (directed) like scheme, where each node or state
will be a set of items with elements that are productions in the
grammar. The elements comprise the core of the items. The edges
representing the transition will be labeled with the symbol for which
the transition from one state to another is predetermined.
</p>
<p>
In the LALR (<i>lookahead</i>-LR) technique, LR items with common core
are coalesced, and the parsing actions are determined on the basis of
the new GOTO function generated. The tables obtained are considerably
smaller than the LR tables, yet most common syntactic constructs of
programming languages can be expressed conveniently by LALR grammar.
</p>
<p>
I am not going deep into construction of tables. Instead, I would like
to explain the use of a tool called <b>Yacc</b> for parser generation.
</p>
<h2><b>Calculator Using Yacc</b></h2>
<p>
Input to Yacc can be divided into three sections:
</p>
<p></p>
<ol>
<li>definitions sections that consists of token declarations, and C
code bracketed by "%{" and "}%"
<li>the BNF grammar in the rules section
<li>and user subroutines in the subroutines section.
</ol>
<p></p>
<p>
We shall illustrate that by designing a small calculator that can
add and subtract numbers. Let us start with the definitions section
for the Yacc input file:
</p>
<p></p>
<pre>
/* File name - calc1.l*/
%{
#include "y.tab.h"
#include &lt; stdlib.h &gt;
void yyerror(char *);
}%
%%
[0-9]+ {
yylval = atoi(yytext);
return INTEGER;
}
[-+\n] {
return *yytext;
}
[ \t] ; /*skip whitespace*/
. yyerror("Unknown character");
%%
int yywrap(void) {
return 1;
}
</pre>
<p></p>
<p>
Yacc when run generates a parser in the file <b>y.tab.c</b>, along side
which another file <b>y.tab.h</b> is also generated. Lex includes this
file and utilizes the definitions for token values. Lex returns the
values associated with the tokens in variable <b>yylval</b>. But to get
tokens, yacc calls <b>yylex</b> the return value of which is integer.
</p>
<p>
The yacc input specification is given below:
</p>
<pre>
/* file name calc1.y */
%{
int yylex(void);
void yyerror(char *);
%}
%token INTEGER
%%
program:
program expr '\n' { printf("%d\n", $2); }
|
;
expr:
INTEGER
| expr '+' expr { $$ = $1 + $3; }
| expr '-' expr { $$ = $1 - $3; }
;
%%
void yyerror(char *s) {
fprintf(stderr, "%s\n", s);
}
int main(void) {
yyparse();
return 0;
}
</pre>
<p></p>
<p>
Here, the grammar is specified using productions. Left hand side of a
production being a non terminal followed by a colon and then the right
hand side of a production. The contents of the braces show the action
associated with the productions. So what does the rules say ?
</p>
<p>
It says that a program consists of zero or more expressions. Each
expression terminates with a newline. When a newline is detected, we
print the value of the expression.
</p>
<p>
Now execute yacc as shown:
</p>
<p></p>
<pre>
yacc -d calc1.l
</pre>
<p></p>
<p>
You get a message "shift/reduce conflict". Shift/reduce conflict arises
when the grammar is ambiguous and there is a possibility of more than
one derivation tree. To understand this, consider the example given in
the stack implementation of shift-reduce parsing. In step 6, instead of
shifting we could have reduced appropriately as per the grammar . Then
addition will have higher precedence over multiplication.
</p>
<p>
Before proceeding you must know about another kind of conflict that is
reduce-reduce conflict. This arises when there are more than one option
for reducing a stack symbol. For example: In the grammar below
<b>id</b> can be reduced to <b>T</b> or <b>E</b>.
</p>
<p></p>
<pre>
E -&gt; T
E -&gt; id
T -&gt; id
</pre>
<p></p>
<p>
Yacc takes a default action when conflicts arise. When there is
shift-reduce conflict, yacc will shift and when there is reduce-reduce
conflict, it will use the first rule in the listing. Yacc also issues a
warning message when conflicts arise. Warnings can be eliminated by
making the grammar unambiguous.
</p>
<p>
Coming back, yacc produces two files; <b>y.tab.c</b> and <b>y.tab.h</b>.
Some lines one has to notice are:
</p>
<p></p>
<pre>
#ifndef YYSTYPE
typedef int YYSTYPE
#endif
#define INTEGER 257
YYSTYPE yylval
</pre>
<p></p>
<p>
Internally, yacc maintains two stacks in memory; a parse stack and a
value stack. The current parsing state is determined by the terminals
and/or non terminals that are present in the parse stack. The value
stack is always synchronized and holds an array of <b>YYSTYPE</b>
elements, which associates a value with each element in the parse stack.
So for example, when lex returns an INTEGER token, yacc shifts this
token to the parse stack. At the same time, the corresponding yylval is
shifted to the value stack. This makes it easier in finding the value
of a token at any given time.
</p>
<p>
So when we apply the rule
</p>
<p></p>
<pre>
expr: expr '+' expr { $$ = $1 + $3; }
</pre>
<p>
we pop <b>"expr '+' expr"</b> and replace it by <b>"expr"</b>. In other
words we replace the right hand side of a production by left hand side
of the same production. Here we pop three terms off the stack and push
back one term. The value stack will contain "$1" for the first term on
the right-hand side of the production, "$2" for the second and so on.
"$$" designates the top of the stack after reduction has taken place.
The above action adds the values associated with two expressions, pops
three terms off the value stack, and pushes back a single sum. Thus the
two stacks remain synchronized and when a newline is encountered, the
value associated with <b>expr</b> is printed.
</p>
<p>
The last function that we need is a 'main'. But the grammar is
ambiguous and yacc will issue shift-reduce warnings and will process
the grammar using shift as the default operation.
</p>
<p>
I am not giving the function here because there is more to learn.
I shall come up with that in the next part. I shall also explain how
to remove ambiguity from the grammar and then design the calculator
for it. In fact, some more funcionalities shall be incorporated into
the grammar to have a better understanding.
<!-- *** BEGIN author bio *** -->
<P>&nbsp;
<P>
<!-- *** BEGIN bio *** -->
<P>
<img ALIGN="LEFT" ALT="[BIO]" SRC="../gx/2002/note.png">
<em>
I am a final year student of Computer Science at Government Engineering
College, Trichur, Kerala, India. Apart from Linux I enjoy reading books
on theoretical physics.
</em>
<br CLEAR="all">
<!-- *** END bio *** -->
<!-- *** END author bio *** -->
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
Copyright &copy; 2003, Hiran Ramankutty.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 87 of <i>Linux Gazette</i>, February 2003
</STRONG></SMALL></CENTER>
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<BIG><BIG><STRONG><FONT COLOR="maroon">I Built a Custom Debian CD from Knoppix</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/sunil.html">Sunil Thomas Thonikuzhiyil</A></STRONG>
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<h3>Introduction</h3>
<p> <20> <20> <a href=http://knopper.net/knoppix>Knoppix </a> is a live cd distribution based on debian GNU/Linux.It contains a large number of applications which can come in handy even on minimal hardware.Knoppix supports alarge number of graphics cards sound cards scsi and USB devices.It can be used as a Linux demo, educational cd, rescue system or adapted and used as a platform for commercial product demo. It is not necesary to install anything to hard disk
There is an installation program which can install the entire cd to a hard disk, if you like. It means that you have a full fledged debian installation in 20 minutes. This document describes how I built a custom live cd from knoppix. My primary motivation to build this cd was to include some of my favorite applications which are missing from stock knoppix CD. <20>If you find any errors in this document please drop me a mail <a href=mailto:sunil_tt@yahoo.com>here </a>
</p>
<h3> Requirements</h3>
<h4> a) Software</h4>
<p> To start with you have to download knoppix image from knoppix site. There is a release every one<6E> or two week. There are 2 images: German and English. I did my setup based on 31-10-2002-EN release. </p>
<p> <20><>If you already have an image you can try to rsync it to the most recent version as below. However don't expect much bandwidth saving since the knoppix image is compressed. If you have a knoppix cdrom create an image by <20>
#dd if=/dev/cdrom of=knoppix.iso)</p>
<p> Rename the Knoppix iso image to reflect the current release name.<br>
<EFBFBD> Example<br>
<20> I have downloaded
KNOPPIX_V3.1-23-10-2002-EN.iso<br>
<20> I want to update it to <20><>KNOPPIX_V3.1-31-10-2002-EN.iso<br>
<20> Rename KNOPPIX_V3.1-23-10-2002-EN.iso
to <20>KNOPPIX_V3.1-31-10-2002-EN.iso<br>
<20>Then <br>
<20>rsync -P --stats ftp.leo.org::Knoppix/KNOPPIX_V3.1-31-10-2002-EN.iso<73>
.<br>
( you can use any other rsync site of knoppix. Always check the site for latest release) </p>
<h4> b) Hardware </h4>
<p> A Computer with tons of free hard disk space and memory. I did this on a Pentium 3 950MHZ machine with 128 mb RAM. </p>
<hr>
<h3> <b>Initial setup<br></b></h3>
<p><EFBFBD>Make a lot of<6F> disk space free<65> You need a lot of real estate for
re-mastering KNOPPIX<49> CD<br>
<20> <20>I made two fresh partitions<6E> on my 20 GB Hard disk<br>
<20> <20> <20> <20> <20> <20>hda2 with 2GB <20>for swap<br>
<20> <20> <20> <20> <20><> hda3 with 5 GB for re-mastering work ( you can also <20>use an existing Linux partition if it has sufficient <20>free space) </p>
<p> <20>Now boot the machine with Knoppix cd ( You can also do the
re-mastering after a <20>hard disk install of knoppix . A how to for hard disk
install<EFBFBD> can be found <a href=http://www.freenet.org.nz/misc/knoppix-install.html> here </a> ) </p>
<p> <20> <20>At boot prompt press enter. Knoppix now boots into GUI. The default is KDE . You<6F> can change it at boot prompt if you want . I did re-mastering <20>while booted to KDE. It is assumed that you are somewhat familiar with Knoppix.
<EFBFBD>Read <20>Knoppix cheat codes on the CD <20>for more information on booting. </p>
<h4> a) Configure networking from the KDE menu </h4>
<EFBFBD> Click on <br>
K/Knoppix/network-Internet/Network-card-configuration <br>
<p> <20> <20> I am connected to a Lan and I configured IP address, netmask, name
server and gateway This step is very important since you have to get the custom stuff to be installed from else where</p>
<h4>b) Setup partitions </h4>
<p> Open a root shell from KDE menu<6E> (K/Knoppix/Root-shell) <20>You will get <20># prompt</p>
<p> Run cfdisk </p>
<p> Next you have to make the necessary <20>partitions . I <20>created two partitions
hda2 with 2 GB and <20>hda3 with 5 GB</p>
<p> Make the 2GB<47> partitions type as swap <20>( /hda2 in my case) </p>
<p> Make the 5 GB partitions type as Linux native( ext2) <20>(hda3 here)<br>
Save the modified partition information </p>
<p> Quit cfdisk </p>
<p> <20>For creating compressed file system we need a lot of swap space .
I created the swap with <br>
<20># mkswap /dev/hda2<br>
<20># swapon /dev/hda2<61> <20> <20> <20> <20> <20> <20> <20> </p>
( it is also possible to use a swap file ) <br>
<p> Create an ext2 file system on the 5GB partition <br>
<20> #<23>mke2fs /dev/hda3 </p>
<p> Mount the 5GB<47> partition to the Knoppix file system <br>
# mount /dev/hda3 /mnt/hda3 </p>
<p> The basic setup for re-mastering is ready </p>
<hr>
<h3><b>Installing and Removing Software</b></h3>
<p> The knoppix CD<43> is organized somewhat like the figure below ( Correct me if I am wrong. it may<61> look different when you look at it from windows or another Linux distro)<br>
<pre>
/--demos
|--talks
|--index.html
|--autorun.bat
|--autorun.inf
|--knoppix.ico
|--KNOPPIX
|--KNOPPIX
|--boot.img
|--background.gif
|- (Some more files here)
</pre>
<p> <20>The file KNOPPIX in <20>/KNOPPIX <20>directory on the cd is approxiamtley
700MB. The file contains a <a
href="http://www.knopper.net/download/knoppix/cloop.README">compressed image
</a>of the file system. We have to modify this file alone and can leave
the rest of <20>the cd intact (unless you want to modify boot image startup
files etc).</p>
<h4> a) Copy Knoppix file system to hard disk </h4>
When Knoppix CD is booted compressed image file is mounted at /KNOPPIX
You have to copy it to your target partition.I did a<br>
# cp -Rp <20>/KNOPPIX <20><> /mnt/hda3/<2F> <br>
( -R option is for recursive copying -p is for preserving ownership time stamp etc) This places all the files you need to make a custom cd on your hard disk <20>at /mnt/hda3/KNOPPIX/ directory . Take a look at it </p>
<h4> b) Chroot </h4>
<p> <20>You have to install/uninstall software under this tree<65>( if you don't have networking copy your sources to <20>(say)<29> /mnt/hda3/KNOPPIX/root/ <20>and if you have debs copy them to<74> /mnt/hda3/KNOPPIX/var/cache/apt/archives)<br>
Now we are going to change the root of the file system to /mn/hda3/KNOPPIX <br>
#chroot /mnt/hda3/KNOPPIX </p>
<p> you will get back # prompt ( If you get /dev/null <20>permission denied message here just press control C)<br>
<20>You<6F> are at <20> / ( chrooted to /mnt/hda3/KNOPPIX) </p>
<p> Next mount the proc file system <br>
#mount -t proc /proc proc <20> <20><br>
<h4> c) Setup networking </h4>
Add to<74> /etc/resolv.conf <br>
nameserver ip-of-ur-nameserver </p>
<i> <20>( I had a curious problem /etc/resolv.conf was a symlink to /etc/dhcp/resolv.conf. Ping did not work. I removed the symlink and created a /etc/resolv.conf afresh and it worked. Make sure that you restore the symlink <20>once you are
finished) </i>
<p> Verify your ip address now with ifconfig. (It should be same as what you have out side chroot) Then try<72> ping google.com. If you<6F> can ping google.com your network setup<75> is ok under chroot.Do an apt get update<74> </p>
<h4> d) Install/Uninstall </h4>
<p> You can install /uninstall whatever software you<6F> need using apt. Since the original Cd has a lot of software installed it may not be an easy
task.The following is a partial list of packages I removed </p>
<h4><b><EFBFBD>Games</b> </h4>
falconseye-data<br>
rocks-n-diamonds<br>
amor<br>
nethack-x11<br>
gnome-games-locale<br>
xboard<br>
gnocatan-client<br>
imaze<br>
kmahjongg<br>
gnome-gnibbles<br>
freeciv-gtk<br>
ktuberling<br>
gnocatan-help<br>
ksirtet<br>
gnome-gnobots2<br>
jumpnbump<br>
ksnake<br>
xgalaga<br>
lskat<br>
katomic<br>
kshisen<br>
konquest<br>
chromium<br>
ktux<br>
moon-buggy<br>
kmoon<br>
ksame<br>
gnuchess<br>
ktron<br>
frozen-bubblekjumpingcube<br>
fortune-mod<br>
kodo<br>
gnocatan-ai<br>
gnocatan-server-console<br>
gnocatan-server-data<br>
nethack<br>
821<br>
fortunes<br>
searchandrescue<br>
xbill<br>
kspaceduel<br>
libkdegames<br>
tipptrainer-data-dexconq<br>
gcompris<br>
gnome-chess<br>
tuxracer-data<br>
abuse-frabs<br>
gnome-gnotski<br>
frotz<br>
kblackbox<br>
gnome-games<br>
gnome-gtali<br>
gnome-iagno<br>
gnome-stones<br>
gnocatan-server-gtk<br>
lxdoom-x11<br>
maelstrom<br>
kabalone<br>
gnome-gnotravex<br>
fortunes-min<br>
chromium-data<br>
kdegames<br>
pingus-data<br>
task-kde-games<br>
stax<br>
gnome-card-games<br>
xtris<br>
xtux<br>
kjezz<br>
lxdoom<br>
<h4><b>Non -free</b><br></h4>
x3270<br>
xanim festlex-oald<br>
netscape-java-477<br>
j2re1.3<br>
3270-common<br>
tgif<br>
giflib-bin<br>
frotz xfractint<br>
giflib3g communicator-smotif-477<br>
netscape-base-477<br>
maelstrom communicator-base-477<br>
gimp1.2-nonfree<br>
acroread<br>
lha<br>
unarj<br>
xsnow<br>
<h4> <b>Misc <20></b> </h4>
tetex-base <br>
tetex-extra <br>
j2re1.3 <20><br>
lyx<br>
acroread <br>
qcad<br>
rocks-n-diamonds<64><br>
kde-i18n-da <br>
kde-i18n-it <br>
kde-i18n-de<br>
kde-i18n-fr<br>
kde-i18n-ru<br>
kde-i18n-nl<br>
kde-i18n-ja<br>
kde-i18n-es<65><br>
kde-i18n-cs <br>
kde-i18n-pl <br>
kde-i18n-tr<br>
xfonts-intl-chinese<br>
kword<br>
kpresenter<br>
abiword-gtk<br>
karbon <br>
kchart<br>
kformula<br>
kivio <br>
koffice-libs <br>
kontour <br>
koshell<br>
kspread <br>
<p><EFBFBD>I copied the above list to a file ( say kicklist)
<20>then did <br>
<20><><EFBFBD> #dpkg -P `cat kicklist` <20><br>
It removed all files listed (notice the back quote
above )</p>
<p>If you are looking for big installed packages <br>
<20><><EFBFBD> <20> # <20>dpkg-awk "Status: .* installed$" -- Package Installed-Size| awk
'{print $2}' | egrep -v '^$' | xargs -n2 echo | perl -pe 's/(\S+)\s(\S+)/$2
$1/' | sort -rg<br>
<20> will list the <20>packages <20>with size in descending order.<br>
</p>
<p> Finally run deborphan to check if there are any orphaned packages<br>
#deborphan &gt; /tmp/orphanlist<br>
#dpkg -P `cat /tmp/orphanlist`<br>
# rm /tmp/orphanlist<73> </p>
<p> An alternate method is to use<73> synaptic and add/remove packages from GUI.
Synaptic is good graphical front end to apt </p>
<p> For this do <br>
# apt-get install synaptic <br>
You have to export DISPLAY environment variable for synaptic to work properly <br>
#DISPLAY=myip:0.0 <20> <20>( replace my ip with your actual IP) <br>
#export DISPLAY <br>
#synaptic </p>
<p> It will start synaptic <br>
Enjoy apt through synaptic
</p>
<p> Once you are finished with synaptic you can re master the cd. If you are <20>working from a hard disk install of knoppix <20>and want synaptic to work, look in/etc/X11/xinit/xserverrc <20>and see that -nolisten tcp is removed.Also do xhost + as a non root user) </p>
<p> Unmount proc <20>( This is very <b>important</b>) <br>
<20>#umount /proc </p>
<p>Press control D to leave chrooted environment<p>
<h3><b>Further Customization</b> <20></h3>
<b> 1<> Installing applications compiled from source </b>
<EFBFBD> <p><EFBFBD>Download the software source inside chroot environment. Compile and install as usual . If it is an X11 application export display before you test<br>
I use checkininstall <a href="asic-linux.com.mx/%7Eizto/checkinstall/">asic-linux.com.mx/~izto/checkinstall/</a> to install and maintain home brew debs<br>
Remember to remove the sources once you are finished (it will take up space on your CD). </p>
<b> 2) <20>Changing user settings</b>
<EFBFBD> <20><p> It is possible to set password for users. Just set it under chrooted
environment </p>
<b> 3) Changing backgrounds </b>
<p> /usr/local/lib/knoppix.gif is the default background image in X </p>
<b> 4) Modifying Boot Screen <20></b>
<p><EFBFBD>The Knoppix Cd uses <a href="http://syslinux.zytor.com/">syslinux</a> to boot. If you want to change the boot screen/messages do the
following. Make a temporary directory on your hard disk (I did mkdir
/mnt/hda3/image)<br>
<20>Copy the boot.img<6D> file from <20>Knoppix <20>directory of your knoppix cd<63><br>
<20><><EFBFBD> <20><> #cp /KNOPPIX/boot.img /mnt/hda3<br>
<20>Mount the image as follows<br>
<20> <20> <20> #<23>mount -t msdos -o loop <20> /mnt/hda3/boot.img <20>/mnt/hda3/image<br>
<20> Now look in the image directory you created. There are a number of interesting <20>files in this directory </p>
<20><> <20>a) Boot logo <br>
logo.16 is the image displayed on boot screen. <20>It is
encoded in a special format. For replacing it grab a 640*400 <20>16 color image. I downloaded an image from gnu.org.<2E>Convert the image to a png file ( call it logo.png)<29> <br>
<pre>
<20><> #pngtopnm &lt;logo.png &gt;logo.pnm<br>
<20> <20><><EFBFBD> #ppmtolss16 &lt;logo.pnm &gt;logo.16<br>
<20><><EFBFBD> # cp logo.16 /mnt/hda3/image/logo.16
</pre>
<p><EFBFBD> (Keep the size of the final log.16 around 50 k). Unmount image directory. Copy the boot.img to a floppy<br>
<20><> #dd if=boot.img of=/dev/fd0<br>
Boot the machine from the floppy you have made.
If it boots up properly you are done </p>
<20>b) <20>syslinux.cfg <br>
<EFBFBD> By modifying syslinux.cfg you can change a number of parameters passwd on to the kernel. Read the man pages of syslinux for more details<br><EFBFBD>
<b> 5)Modifying<6E> kernel <20>( ****Untested<65> ****)</b>
<EFBFBD><EFBFBD> <20> <20> <20><p> Make a <20>new custom kernel using kernel package . Keep the kernal
size small. Copy the kernal to and modules to boot.img file. replace /lib/modules/2.4.19-xfs<66> with <20>modules of your new kernel<br>
<20><> Replace files in<69> /boot <20>
</p>
<b> 6)Changing default GUI to Gnome/ icewm </b></br>
<20>Changing default gui to something else is quite easy<br>
<20> Under the chrooted environment <20>open the file <br>
<20><><EFBFBD><EFBFBD> /etc/init.d/knoppix-autoconfig </p>
<p> <20> Look for the following lines<br>
---------------------------------------<br>
<p>#Also read desired desktop, if any </p>
<p>DESKTOP="$(getbootparam desktop 2&gt;/dev/null)"</p>
<p># Allow only supported windowmanagers </p>
<p>case "$DESKTOP" in gnome|kde|larswm|xfce|windowmaker|wmaker|icewm|fluxbox|twm)
;; *)
</p>
<p><EFBFBD> DESKTOP="KDE"; ;; esac<br>
-------- <20> <20> <20>^^ <20> --------------------------------------<br>
</p>
<p><EFBFBD> Change the KDE above to gnome and that is all<6C> </p>
<b> <20>7) <20>Remove any temporary files<65> </b><br>
<20><><EFBFBD> a) <20> Look in /root <20>for hidden files such as .bash_history .viminfo<br>
<20> <20> b) <20> Nuke all deb files in <20>/var/cache/apt/archives<65><br>
<20><><EFBFBD> <20>c) <20>Run the knoppix.clean script <20> ( Be careful and run
it only from <20>chrooted environmant) </p>
<p><EFBFBD>(* link to the script goes here*) <20><> <20><><EFBFBD></p>
<h3><u><b>Re mastering the CD</b></u> </h3>
<b>a)Make an ISO image</b>
<p> <20>1)<29> Make a new directory on /mnt/hda3<br>
<20><> I called it NewCd<br>
<20><> <20>Copy Everything except Compressed image file(KNOPPIX) from
knoppix cd (look at /cdrom). You can safely delete the directories demos and <20>talks <br>
<EFBFBD> 2) Create the compressed Image<br>
<20> <20>#mkisofs -R <20> /mnt/hda3/KNOPPIX<49> |<7C> create_compressed_fs - <20> 65536 <20>&gt; /mnt/hda3/NewCD/KNOPPIX/KNOPPIX <20><></p>
<p><EFBFBD>3) Recreate the bootable CD <br>
<20>#cd /mnt/hda3 </p>
<p><EFBFBD>#mkisofs -r -J -b KNOPPIX/boot.img -c KNOPPIX/boot.cat <20> -o myknoppix.iso <20>NewCd </p>
<b>b)Testing the image </b>
<p> Create a boot floppy <br>
# dd if=/mnt/hda3/KNOPPIX/boot.img of=/dev/fd0<64> <br>
Copy the compressed file you created to a directory /KNOPPIX on any partition. The boot floppy i will look for /KNOPPIX/KNOPPIX<49>on hard disk partitions.This makes your testing easy. Once you are satisfied with your image burn
itto a CD <20> </p>
<h3><b>FAQ </b> </h3>
<p> <20>1) How do I <20>stop konquerer at startup<br>
<20> To stop konquerers you <20>have to modify<br>
<EFBFBD> <20> <20> <20> /etc/X11/Xsession.d/45xsession<br>
<EFBFBD><EFBFBD><EFBFBD> Look for the following lines </p>
<p>-------------------------------------------<br>
if [ -e "$INDEXFILE" ]; then<br>
cat &gt;&gt; $HOME/Desktop/KNOPPIX.desktop &lt;&lt;EOF<br>
[Desktop Entry]<br>
Name=KNOPPIX<br>
Exec=kfmclient openProfile webbrowsing $INDEXFILE<br>
Type=Application<br>
Icon=html<br>
Terminal=0<br>
EOF<br>
ln $HOME/Desktop/KNOPPIX.desktop $HOME/.kde/Autostart/showindex.desktop<br>
fi</p>
-----------------------------------------<2D><br>
<p> <20>It makes an autostart file. Comment it <20>out </p>
<p> 2) I have booted knoppix cd and mounted a hard disk how do i copy something via scp to the hard disk<br>
<20><><EFBFBD> <20> Open a <20>shell <br>
<20><><EFBFBD> <20> set a password for user knoppix<br>
<20><><EFBFBD> <20> start ssh <20>(/etc/init.d/ssh start)<br>
<20><><EFBFBD> <20> Then copy with scp</p>
<p><EFBFBD>3 I am at $ prompt I want to su<br>
<20><><EFBFBD> <20><>Do <20>sudo <20>passwd <br>
<20><><EFBFBD> <20> set a <20>root password<br>
<20><><EFBFBD> <20><>then su
</p>
<p><EFBFBD>4) default text mode boots up in frame buffer and characters are very small
how do I fix it<br>
<20> <20> <20>Mount boot.img<br>
<20><><EFBFBD> <20>look for syslinux.cfg<br>
<20><><EFBFBD> <20>under <20>Default <20>vmlinuz<br>
<20><><EFBFBD> <20>change VGA=791 to VGA=normal </p>
<p> 5 )My keyboard lay out is<69> German. <20>How do i change it to English<br>
<20>Open KDE control center select system -&gt;keyboard and change
it to US English </p>
<h3> References</h3>
<20> <20> <20> I have adapted lot of material from the following links. Also #knoppix
on irc.freenode.net is a good source of information <br>
1)<a href=http://home.bellsouth.net/p/PWP-tech2k>Tech2k home page </a><br>
<b>Ken Burk</b> helped me a lot on irc to improve this document . His site has excellent information which you can always rely on.<2E>His kix remastering page is also very good<br>
2) <a href=http://knoppix.net> Knoppix.net </a><br>
<EFBFBD> The unofficial knoppix site is a great <20>source <20>of information. Lots of new stuff regarding re-mastering appear there regularly <br>
3) <a href= http://www.linuxtag.org/forum/> Knoppix forum </a> at linuxtag<br>
This site mixture of German and English . Very good source
on Knoppix </p>
<!-- *** BEGIN author bio *** -->
<P>&nbsp;
<P>
<!-- *** BEGIN bio *** -->
<P>
<img ALIGN="LEFT" ALT="[BIO]" SRC="../gx/2002/note.png">
<em>
I work as consultant information technology at the Kerala Legislative
Assembly Trivandrum India. I have been hooked on Linux since 1996. I have a
Masters in Computer Science from Cochin University. I am interested in all
sorts of operating systems. In my free time I love to listen to Indian
classical music.
</em>
<br CLEAR="all">
<!-- *** END bio *** -->
<!-- *** END author bio *** -->
<!-- *** BEGIN copyright *** -->
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<CENTER><SMALL><STRONG>
Copyright &copy; 2003, Sunil Thomas Thonikuzhiyil.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 87 of <i>Linux Gazette</i>, February 2003
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<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
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<CENTER>
<BIG><BIG><STRONG><FONT COLOR="maroon">Encryption using OpenSSL's crypto libraries</FONT></STRONG></BIG></BIG>
<BR>
<STRONG>By <A HREF="../authors/vinayak.html">Vinayak Hegde</A></STRONG>
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<!-- END header -->
<h2> Motivation for the article </h2>
<p align="justify">
Linux has already made quite a few inroads into the corporate world.
One of the persistent demands of the corporate world has been a need
for better data security. This is where encryption comes in, to hide
sensitive data from a third party intruder. Open-source software
has a reputation for secure programming. This article is another
step in that direction.
</p>
<p align="justify">
OpenSSL's libcrypto is a really good library if you want to use encryption
without bothering with the details of underlying implementation of the
algorithm. The problem is that the documentation is really minimal.
You can obviously read the source and figure out what going on. Also the
fact that function names are intuitive helps to some extent. Another way
of getting help is joining the various mailing lists from the
<a href="www.openssl.org"> OpenSSL </a> website.
However the command line tools of OpenSSL are pretty well documented and
easy to use. I shall explain in this article how to use the blowfish
algorithm for encryption using OpenSSL's crypto libraries.
</p>
<h2> Some Background Information</h2>
<p align="justify">
During the early days of cryptography, algorithms as well as keys were
secret. However now that trend has changed. Now algorithms are publicly
known and keys are kept secret. The best example of this is the RSA
algorithm which is widely known and implemented. The public key are
known to the world but the private keys are kept secret. RSA is an
asymmetric algorithm as it does not use the same key for encryption
and decryption. Also it is generally not advisable to use RSA for
encrypting large amounts of data as the it is computationally intensive.
</p>
<p align="justify">
For encrypting large amounts of data, generally less computationally
intensive algorithms are prefered. In this article we use the blowfish
algorithm for encrypting and decrypting data. Blowfish is a symmetric
algorithm which means it uses the same key for encryption and
decryption. Blowfish was designed by the famous cryptographer Bruce Schneier.
Blowfish is a fast algorithm for encryption/decryption.
</p>
<h2> Generating the key</h2>
<p align="justify">
For the purposes of demonstration we shall use a 128-bit key. This is
stored as an character array in the program. We also generate an 64 bit
initialization vector(IV). For our program we will use <b> Cipher Block
Chaining (CBC) </b> mode. Also we will not use the blowfish functions directly
but use then through a the higher level interface.
</p>
<p align="justify">
An <b>initialization vector</b> is a bit of random information that is used as
an input in chained encryption algorithms, that is, when each stage of
encrypting a block of input data provides some input to the encryption
of the next block. (blowfish uses 64-bit blocks for encryption).
The IV provides the first bit of input for encrypting the
1st block of data, which then provides input for the
2nd block and so on. The bit left over at the end is discarded.
</p>
<p align="justify">
The random bits are generated from the character special file <b> /dev/random
</b> which provides a good source for random numbers. See the manpage for more
information.
</p>
<table border = 2>
<tr> <td bgcolor=#FFFF99>
<pre>
int
generate_key ()
{
int i, j, fd;
if ((fd = open ("/dev/random", O_RDONLY)) == -1)
perror ("open error");
if ((read (fd, key, 16)) == -1)
perror ("read key error");
if ((read (fd, iv, 8)) == -1)
perror ("read iv error");
printf("128 bit key:\n");
for (i = 0; i < 16; i++)
printf ("%d \t", key[i]);
printf ("\n ------ \n");
printf("Initialization vector\n");
for (i = 0; i &lt; 8; i++)
printf ("%d \t", iv[i]);
printf ("\n ------ \n");
close (fd);
return 0;
}
</pre>
</td> </tr>
</table>
<h2> The Encryption routine </h2>
<p align="justify">
The encryption routine takes two parameters - the file descriptors of input file and
the output file to which the encrypted data is to be saved. It is always a good idea
to zero-fill your buffers using the memset or bzero commands before using the buffers
with data. This is especially important if you plan to reuse the buffers. In the program
below, the input data is being encrypted in blocks of 1K each.
</p>
<p align="justify">
The steps for encryption are as follows :-
<ol>
<li> Create a cipher context </li>
<li> Initialize the cipher context with the values of Key and IV </li>
<li> Call EVP_EncryptUpdate to encrypt successive blocks of 1k eack </li>
<li> Call EVP_EncryptFinal to encrypt "leftover" data </li>
<li> Finally call EVP_CIPHER_CTX_cleanup to discard all the sensitive information from memory </li>
</ol>
</p>
<p align="justify">
You may be wondering what "leftover" data is? As mentioned earlier, Blowfish
encrypts information in blocks of 64-bit each. Sometimes we may not have 64 bits
to make up a block. This may happen if the buffer size in the program below or
the file/input data size is not a integral multiple of 8 bytes(64-bits).So
accordingly the data is padded and then the partial block is encrypted using
EVP_EncryptFinal. The length of the encoded data block is stored in the
variable tlen and added to the final length.
</p>
<table border = 2>
<tr> <td bgcolor = #FFFF99>
<pre>
int
encrypt (int infd, int outfd)
{
unsigned char outbuf[OP_SIZE];
int olen, tlen, n;
char inbuff[IP_SIZE];
EVP_CIPHER_CTX ctx;
EVP_CIPHER_CTX_init (&amp; ctx);
EVP_EncryptInit (&amp; ctx, EVP_bf_cbc (), key, iv);
for (;;)
{
bzero (&amp; inbuff, IP_SIZE);
if ((n = read (infd, inbuff, IP_SIZE)) == -1)
{
perror ("read error");
break;
}
else if (n == 0)
break;
if (EVP_EncryptUpdate (&amp; ctx, outbuf, &amp; olen, inbuff, n) != 1)
{
printf ("error in encrypt update\n");
return 0;
}
if (EVP_EncryptFinal (&amp; ctx, outbuf + olen, &amp; tlen) != 1)
{
printf ("error in encrypt final\n");
return 0;
}
olen += tlen;
if ((n = write (outfd, outbuf, olen)) == -1)
perror ("write error");
}
EVP_CIPHER_CTX_cleanup (&amp; ctx);
return 1;
}
</pre>
</td> </tr>
</table>
<h3> The Decryption routine </h3>
<p align="justify">
The decryption routine basically follows the same steps as the encryption routine. The following code show how the decryption is done.
<table border = 2>
<tr> <td bgcolor = #FFFF99>
<pre>
int
decrypt (int infd, int outfd)
{
unsigned char outbuf[IP_SIZE];
int olen, tlen, n;
char inbuff[OP_SIZE];
EVP_CIPHER_CTX ctx;
EVP_CIPHER_CTX_init (&amp; ctx);
EVP_DecryptInit (&amp; ctx, EVP_bf_cbc (), key, iv);
for (;;)
{
bzero (&amp; inbuff, OP_SIZE);
if ((n = read (infd, inbuff, OP_SIZE)) == -1)
{
perror ("read error");
break;
}
else if (n == 0)
break;
bzero (&amp; outbuf, IP_SIZE);
if (EVP_DecryptUpdate (&amp; ctx, outbuf, &amp; olen, inbuff, n) != 1)
{
printf ("error in decrypt update\n");
return 0;
}
if (EVP_DecryptFinal (&amp; ctx, outbuf + olen, &amp; tlen) != 1)
{
printf ("error in decrypt final\n");
return 0;
}
olen += tlen;
if ((n = write (outfd, outbuf, olen)) == -1)
perror ("write error");
}
EVP_CIPHER_CTX_cleanup (&amp; ctx);
return 1;
}
</pre>
</td> </tr>
</table>
<h2> The complete code </h2>
<p align="justify">
A minimal interactive program implementing the above routines can be
downloaded from <a href="misc/vinayak/sym_funcs.c.txt"> here </a>.
The command for compiling the program is
<table border = 2 >
<tr> <td bgcolor = #FFAADD>
<pre>
# gcc -o blowfish sym_funcs.c -lcrypto
</pre>
<td> </tr>
</table>
The program takes three files from the command line
<ol>
<li> File to be encrypted </li>
<li> File is which the encrypted data is to be stored </li>
<li> File in which decrypted data is to be stored </li>
</ol>
Don't forget to generate a key before encrypting ;).
</p>
<h2> An Example Application - A Secure Instant Messenger </h2>
<p align="justify">
Consider an instant messenger software (IM) which wants to communicate with
another IM securely. The following approach could be followed.
<ol>
<li> Each IM client has it's own public and private key.
<li> The IM client has the public keys of all the IMs it wants to communicate with.
(say friends' IMs).
<li> The session key is generated by the client which initiates the connection.
This session key is used for encrypting the messages between the two clients.
<li> The session key is encrypted and exchanged between two/multiple clients using public-Key
encryption.(eg. RSA algorithm). Thus Authentication is also taken care of.
<li> The exchange of encrypted data (using Blowfish symmetric encryption) thereafter
takes place between the different clients after this "security handshake".
</ol>
</p>
<h2> Resources </h2>
<ol>
<li> <a href="http://www.openssl.org"> OpenSSL Homepage </a>
<li> <a href="http://www.counterpane.com/blowfish.html"> The Blowfish Algorithm </a>
<li> <a href="http://www.cacr.math.uwaterloo.ca/hac/"> Handbook of Applied Cryptography </a>
</ol>
<!-- *** BEGIN author bio *** -->
<P>&nbsp;
<P>
<!-- *** BEGIN bio *** -->
<P>
<img ALIGN="LEFT" ALT="[BIO]" SRC="../gx/2002/note.png">
<em>My life changed since I discovered Linux. Suddenly Computers became
interesting as i could try out lots of stuff on my Linux box due to the easy
availabily of source code. My interests are predominantly in the fields of
networking, embedded systems and programming languages. I currently work for
Aparna Web services where we make Linux accessible for academia/corporations by
configuring remote boot stations (Thin Clients).
</em>
<br CLEAR="all">
<!-- *** END bio *** -->
<!-- *** END author bio *** -->
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Copyright &copy; 2003, Vinayak Hegde.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
Published in Issue 87 of <i>Linux Gazette</i>, February 2003
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<a name="spam"></a>
<P> <hr> <P>
<!--====================================================================-->
<center><H3><font color="maroon">World of Spam</font></H3></center>
<P> <HR> <P>
<!--======================================================================-->
<P> The Nigeria scams riled up one person enough to write a parody
spam.
<PRE>
X-Spam-Status: No, hits=4.3 required=5.0
tests=BILLION_DOLLARS,DEAR_SOMETHING,IN_REP_TO,ITS_LEGAL,
LINES_OF_YELLING,LINES_OF_YELLING_2,LINES_OF_YELLING_3,
NIGERIAN_TRANSACTION_1,NIGERIAN_TRANSACTION_2,REFERENCES,
SIGNATURE_SHORT_DENSE,SPAM_PHRASE_05_08,SUPERLONG_LINE,
UPPERCASE_75_100,USER_AGENT,USER_AGENT_MUTT,US_DOLLARS_3
version=2.43
X-Spam-Level: ****
HIGHLY CONFIDENTIAL
FROM: GEORGE WALKER BUSH
DEAR SIR / MADAM,
I AM GEORGE WALKER BUSH, SON OF THE FORMER PRESIDENT OF THE UNITED STATES OF
AMERICA GEORGE HERBERT WALKER BUSH, AND CURRENTLY SERVING AS PRESIDENT OF THE
UNITED STATES OF AMERICA. THIS LETTER MIGHT SURPRISE YOU BECAUSE WE HAVE NOT
MET NEITHER IN PERSON NOR BY CORRESPONDENCE. I CAME TO KNOW OF YOU IN MY SEARCH
FOR A RELIABLE AND REPUTABLE PERSON TO HANDLE A VERY CONFIDENTIAL BUSINESS
TRANSACTION, WHICH INVOLVES THE TRANSFER OF A HUGE SUM OF MONEY TO AN ACCOUNT
REQUIRING MAXIMUM CONFIDENCE.
I AM WRITING YOU IN ABSOLUTE CONFIDENCE PRIMARILY TO SEEK YOUR ASSISTANCE IN
ACQUIRING OIL FUNDS THAT ARE PRESENTLY TRAPPED IN THE REPUBLIC OF IRAQ. MY
PARTNERS AND I SOLICIT YOUR ASSISTANCE IN COMPLETING A TRANSACTION BEGUN BY MY
FATHER, WHO HAS LONG BEEN ACTIVELY ENGAGED IN THE EXTRACTION OF PETROLEUM IN
THE UNITED STATES OF AMERICA, AND BRAVELY SERVED HIS COUNTRY AS DIRECTOR OF THE
UNITED STATES CENTRAL INTELLIGENCE AGENCY.
IN THE DECADE OF THE NINETEEN-EIGHTIES, MY FATHER, THEN VICE-PRESIDENT OF THE
UNITED STATES OF AMERICA, SOUGHT TO WORK WITH THE GOOD OFFICES OF THE PRESIDENT
OF THE REPUBLIC OF IRAQ TO REGAIN LOST OIL REVENUE SOURCES IN THE NEIGHBORING
ISLAMIC REPUBLIC OF IRAN. THIS UNSUCCESSFUL VENTURE WAS SOON FOLLOWED BY A
FALLING OUT WITH HIS IRAQI PARTNER, WHO SOUGHT TO ACQUIRE ADDITIONAL OIL
REVENUE SOURCES IN THE NEIGHBORING EMIRATE OF KUWAIT, A WHOLLY-OWNED
U.S.-BRITISH SUBSIDIARY.
MY FATHER RE-SECURED THE PETROLEUM ASSETS OF KUWAIT IN 1991 AT A COST OF
SIXTY-ONE BILLION U.S. DOLLARS ($61,000,000,000). OUT OF THAT COST,
THIRTY-SIX BILLION DOLLARS ($36,000,000,000) WERE SUPPLIED BY HIS PARTNERS IN
THE KINGDOM OF SAUDI ARABIA AND OTHER PERSIAN GULF MONARCHIES, AND SIXTEEN
BILLION DOLLARS ($16,000,000,000) BY GERMAN AND JAPANESE PARTNERS.
BUT MY FATHER'S FORMER IRAQI BUSINESS PARTNER REMAINED IN CONTROL OF THE
REPUBLIC OF IRAQ AND ITS PETROLEUM RESERVES.
MY FAMILY IS CALLING FOR YOUR URGENT ASSISTANCE IN FUNDING THE REMOVAL OF THE
PRESIDENT OF THE REPUBLIC OF IRAQ AND ACQUIRING THE PETROLEUM ASSETS OF HIS
COUNTRY, AS COMPENSATION FOR THE COSTS OF REMOVING HIM FROM POWER.
UNFORTUNATELY, OUR PARTNERS FROM 1991 ARE NOT WILLING TO SHOULDER THE BURDEN OF
THIS NEW VENTURE, WHICH IN ITS UPCOMING PHASE MAY COST THE SUM OF 100 BILLION
TO 200 BILLION DOLLARS ($100,000,000,000 - $200,000,000,000), BOTH IN THE
INITIAL ACQUISITION AND IN LONG-TERM MANAGEMENT.
WITHOUT THE FUNDS FROM OUR 1991 PARTNERS, WE WOULD NOT BE ABLE TO ACQUIRE THE
OIL REVENUE TRAPPED WITHIN IRAQ. THAT IS WHY MY FAMILY AND OUR COLLEAGUES ARE
URGENTLY SEEKING YOUR GRACIOUS ASSISTANCE. OUR DISTINGUISHED COLLEAGUES IN THIS
BUSINESS TRANSACTION INCLUDE THE SITTING VICE-PRESIDENT OF THE UNITED STATES OF
AMERICA, RICHARD CHENEY, WHO IS AN ORIGINAL PARTNER IN THE IRAQ VENTURE AND
FORMER HEAD OF THE ALLIBURTON OIL COMPANY, AND CONDOLEEZA RICE, WHOSE
PROFESSIONAL DEDICATION TO THE VENTURE WAS DEMONSTRATED IN THE NAMING OF A
CHEVRON OIL TANKER AFTER HER.
I WOULD BESEECH YOU TO TRANSFER A SUM EQUALING TEN TO TWENTY-FIVE PERCENT
(10-25 %) OF YOUR YEARLY INCOME TO OUR ACCOUNT TO AID IN THIS IMPORTANT
VENTURE. THE INTERNAL REVENUE SERVICE OF THE UNITED STATES OF AMERICA WILL
FUNCTION AS OUR TRUSTED INTERMEDIARY. I PROPOSE THAT YOU MAKE THIS TRANSFER
BEFORE THE FIFTEENTH (15TH) OF THE MONTH OF APRIL.
I KNOW THAT A TRANSACTION OF THIS MAGNITUDE WOULD MAKE ANYONE APPREHENSIVE AND
WORRIED. BUT I AM ASSURING YOU THAT ALL WILL BE WELL AT THE END OF THE DAY. A
BOLD STEP TAKEN SHALL NOT BE REGRETTED, I ASSURE YOU. PLEASE DO BE INFORMED
THAT THIS BUSINESS TRANSACTION IS 100% LEGAL. IF YOU DO NOT WISH TO CO-OPERATE
IN THIS TRANSACTION, PLEASE CONTACT OUR INTERMEDIARY REPRESENTATIVES TO FURTHER
DISCUSS THE MATTER.
I PRAY THAT YOU UNDERSTAND OUR PLIGHT. MY FAMILY AND OUR COLLEAGUES WILL BE
FOREVER GRATEFUL. PLEASE REPLY IN STRICT CONFIDENCE TO THE CONTACT NUMBERS
BELOW.
SINCERELY WITH WARM REGARDS,
GEORGE WALKER BUSH
</PRE>
<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>
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Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR>
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