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<H2>October 2002, Issue 83 &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
Published by <I>Linux Journal</I></H2> 

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<UL>
	<LI>  <a HREF="lg_mail.html">The MailBag</A> 
	<LI>  <a HREF="lg_tips.html">More 2-Cent Tips</A> 
	<LI>  <a HREF="lg_answer.html">The Answer Gang</A> 
	<LI>  <a HREF="lg_bytes.html">News Bytes</A> 
	<LI>  <a HREF="evans.html">Saving Users From Themselves -or- Dealing with User Input in Python</A> , <EM>by Paul Evans</EM>
	<LI>  <a HREF="heriyanto.html">Creating Makefiles: A Mini Tutorial</A> , <EM>by Tedi Heriyanto</EM>
	<LI>  <a HREF="klimkiewicz.html">Multi-Account E-mail with Mutt</A> , <EM>by Kamil Klimkiewicz</EM>
	<LI>  <a HREF="okopnik.html">Replicating a Linux System - Yet Another Method</A> , <EM>by Ben Okopnik</EM>
	<LI>  <a HREF="padala.html">Exploring Perl Modules - Part2: Creating Charts with GD::Graph</A> , <EM>by Pradeep Padala</EM>
	<LI>  <a HREF="prasad.html">Handling Power Status Using snmptrapd</A> , <EM>by A B Prasad</EM>
	<LI>  <a HREF="qubism.html">Qubism</A> , <EM>by Jon "Sir Flakey" Harsem</EM>
	<LI>  <a HREF="ramankutty.html">Programming in Ruby, part 2</A> , <EM>by Hiran  Ramankutty</EM>
	<LI>  <a HREF="sandeep.html">Process Tracing Using Ptrace, part 2</A> , <EM>by Sandeep S</EM>
	<LI>  <a HREF="stoddard.html">DVD Authoring</A> , <EM>by Chris Stoddard</EM>
	<LI>  <a HREF="thangaraju.html">Risk-Free Resource Allocation for I/O Memory-Mapped Device Drivers</A> , <EM>by Dr B Thangaraju</EM>
	<LI>  <a HREF="tougher.html">Apache Log Analysis Using Python</A> , <EM>by Rob Tougher</EM>
	<LI>  <a HREF="ward.html">Subnetting your local network with DHCP</A> , <EM>by Alan Ward</EM>
	<LI>  <a HREF="lg_backpage.html">The Back Page</A> , <EM>by Mike ("Iron") Orr</EM>
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<H3 ALIGN="center"><EM>Linux Gazette</EM> Staff and The Answer Gang</H3>
<BLOCKQUOTE>
<STRONG>Editor:</STRONG> Michael Orr<BR>
<STRONG>Technical Editor:</STRONG> Heather Stern<BR>
<STRONG>Senior Contributing Editor:</STRONG> Jim Dennis<BR>
<STRONG>Contributing Editors:</STRONG>
Ben Okopnik, Dan Wilder, Don Marti
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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">The Mailbag</FONT></STRONG></BIG></BIG><BR>
<!-- BEGIN wanted -->

<STRONG>From <A HREF="mailto:gazette@ssc.com">The Readers of <i>Linux Gazette</I></A></STRONG></BIG>
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<P>

<HR>
<center>
<BIG><STRONG><FONT COLOR="maroon">HELP WANTED : Article Ideas</FONT></STRONG></BIG>
<BR>
<STRONG>Submit comments about articles, or articles themselves (after reading <a href="http://www.linuxgazette.com/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="../tag/members-faq.html">The Answer Gang</A>. 
</STRONG>
</center><HR>
<UL>
<!-- index_text begins -->
<li><A HREF="#wanted/1"
	><strong>An idea to the Linux Project. Make a complete new Help System/manuals  :-)</strong></a>
<li><A HREF="#wanted/2"
	><strong>PC-MOS</strong></a>
<li><A HREF="#wanted/3"
	><strong>Minimal Linux (Redhat 7.2) Installation</strong></a>
<li><A HREF="#wanted/4"
	><strong>U of Phoenix</strong></a>
<!-- index_text ends -->
</UL>
<!--     .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.     -->
<P> <A NAME="wanted/1"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">An idea to the Linux Project. Make a complete new Help System/manuals  :-)</FONT></H3>
Thu, 26 Sep 2002 14:18:11 +0200
<BR>Niels Larsen (<a href="mailto:linux-questions-only@ssc.com?cc=torvalds@transmeta.com&cc=njlarsen@tiscali.se&subject=%20Re%3A%20%5BLG%2083%5D%20help%20wanted%20%231better%20manuals">njlarsen from tiscali.se</a>)



<blockquote><font color="#000066">As I initially planned to go after this with the Editors' 
Scissors I couldn't decide quite what to snip without having to put my own nickel's
worth in at multiple places.  Leaving it intact is a better example of
the sort of ordinary soul who wants a simple set of instructions.
</font></blockquote>
<blockquote><font color="#000066">I'll suffice to say that I favor his attitude, but fear 
the sort of people who already have even heard of <EM>Linux Gazette</EM> might be above his
"level 1" threshold, and he is not in the least bit clear where to draw
dividers for his other 4 levels.  He also shows a bit of intelligence
and may be beyond "level 1" himself, too.
</font></blockquote>
<blockquote><font color="#000066">Many commercial distros come with "quick start" guides 
geared for the discs in the package.  If you need that, I urge you, it's worth spending
the money.
</font></blockquote>
<blockquote><font color="#000066">Beyond a fairly minimum start, what's a spreadsheet if 
you won't put numbers in it, an email program if you can't decide who to send mail
to ... do we know any mail programs that will tell you why not to
spam before letting you use them?   There is more to life than simply
being told, step by step, which button to push.
</font></blockquote>
<blockquote><font color="#000066">On the other hand, the big name distros at this point 
have so many applications in them that a "level 1" manual covering each would get so
huge no level 1 personality would dare crack it, or the set of them, open.
We used to have it as a cartoon on the wall back when I was in tech
support:  "I can tell I'm getting to this guy.  I heard him open the
shrink wrap on the manual."
</font></blockquote>
<blockquote><font color="#000066">But we will cheerfully point a News Byte entry at 
resources that make some effort to divide up the world of Linux info along the lines of
how much experience you have.   And yes, Mr. Larsen, that will require
us to point you at a website somewhere.  The weapon, should it come
to exist, is no good if we truly keep it a secret.
 -- Heather</font></blockquote>
<P>
This mail is about making an even better manual -and help system, which
ordinary endusers can understand, and read and USE.  <em>smile - positive -
friendly - but not clever</em> 
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)" 
		height="24" width="20" align="middle">
</P>
<P>
I am sorry, that I try to pass my idea around to various people by
e-mail, but I have not yet found out the perfect way to do do.
</P>
<P>
I hope, that my ideas would saw an even better idea, because I am not
that clever.
</P>
<P>
I am running my private "war" <EM>laugh</EM> to make Linux user friendly.
</P>
<P>
And this is my contribution to the Linux Project, I mean this idea.
</P>
<P>
If you don't like me, just scrap this letter 
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)" 
		height="24" width="20" align="middle">
</P>
<P>
There is sitting so many ordinary people out there, surfing the
internet, using windows, and having lots of problems. So it is for me. I
have worked with win3.11, 95 and now win 98. The screen freeze, programs
cannot work together and so on. You probably know?
</P>
<P>
Therefore I now find that "D-day" has come, to attack.       <EM>joking</EM>
</P>
<P>
It is time to make the millions og people, surfing the Internet, shift
from windows to Linux.
</P>
<P>
But in order to accomplish this, it is needed with a campagn called:
"Now Linux has become really userfriendly to install, use and surf the
internet with", or maybe a better name ?  
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)" 
		height="24" width="20" align="middle">
</P>
<P>
Therefore my idea goes towards making e.g. 5 levels of help manuals.
The total easy manual could be level 1. The levels for the professionals
2 - 5 <EM>hi</EM>
</P>
<P>
Keep -and continue developing Linux and its help -and manualsystem as
is.
</P>
<P>
This level 1 manual should be made, by letting a completely newbie sit
next to an Linux expert. Then they together shall install -and use
Linux, and the necessary programs. Then let's say, a journalist shall
write alle the stupid questions down into a manual. Just like the
conversation goes on. It must be completely simple, only ordinary words.
</P>
<P>
E.g. "You take the Linux cd called binary 1, and put it into the cd box"
and so on !!  
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)" 
		height="24" width="20" align="middle">
The whole way, like this.
</P>
<P>
Then the same thing with all the important everyday programs. I mention:
Start and log into Linux
Connection to the internet - set up same -browser - mail program - news
program - text editor - spread sheet - zip program - backup program -
pgp program - wine - direct cable - real player - scandisk - webcopier
(wget) - how to install a new program - and to remove it - and probably
some more. Those are my minimum windows programs.
I just mention those I use. I mean just the minimum number of programs.
All above programs shall have this minimum level 1 manual, so people can
start using Linux and more important open the individual program and
immediately start using it.
Only the minimum points, so you do not have to read pages and pages, to
make it work.
And please lots and LOTS OF EXAMPLET. That is the simplest way.
</P>
<P>
Keep all the existing (man - info - howto etc) as is. They belong to
level 2 - 5 !!  
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)" 
		height="24" width="20" align="middle">
They shall be used as cross reference. But here also is needed a
complete Linux reference book, covering about everyting, because Linux
now is so extensive.
</P>
<P>
I know, because I was at one point working with the High Pack surveying
program. It came with huge manuals. Nobody was able to read it, og had
the time. Then I made a manual of some a4 pages. I just wrote down just
what I did, which buttons I pressed.
</P>
<P>
If you do not change attitude towards the paedagogic principles,
concerning using computer programs, one do not move much towards getting
people using Linux.
</P>
<P>
Only the minimum programs and their level 1 manuals, so people can begin
using Linux. Then they later can fiddle into the more extensive matters,
if they want to, or are able to.
</P>
<P>
Also, tell the programmers, to make their user programs simpler, and not
having so many possibilities. Because it confuses normally people.
</P>
<P>
I say, make it SIMPLE and "talking" normally language, Do not call
things devices, but floppy, cd, etc. because people do not understand
it, and they then just stick to windows, because they have been
brainwashed to use this!
</P>
<P>
Hope you get my message???     
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)" 
		height="24" width="20" align="middle"> 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle"> 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle"> 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle"> 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle"> 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle">
</P>
<P>
I repeat, keep the existing as is, but make this simple manual, as the
secret weapon of Linux.
I shall here in the end just mention, that I gave above idea to Bill
Gates. But he just told me to approach him with a lawyer. He was afraid
to be sued by me. But that is not my idea. Just giving a suggestion.
</P>
<P>
Maybe you can get just a tiny new thinking from this letter.
</P>
<P>
I am an old pensioner, and I can only give this idea, as my contribution
to the Linux Project, which I find fantastic. But I still have
difficulties in getting my Linux work. I cannot remember all I read. And
please also free us from this phrase: "just go to this and this
website". It is ok on level 2 - 5.
</P>
<P>
I am wondering, that now data programs has existed for so long, but
still one is using this ridiculous complex manuals. I think programmers
has been brainwashed by windows manuals/help system, which really is no
good.
</P>
<P>
I think that the closest way to get enduser using Linux in buried in the
help system, which has been neclected, I think ! I think this clever
programmers are buried in the very programming, and are missing the link
to the end-user
</P>
<P>
An example of what I mean:
Word Perfect is a program, which main purpose is to be used to write a
letter:
In order to use the program do the following:
1. To open the program do so and so....
2. To write a letter do so and so....
3. When you have written the letter you should save it to both a harddisk and a floppy disk. Do so and so....
4. To print the letter do so and so......
5. And so on......
All the smart gadgets with the program is not necessary to show.
</P>
<P>
I mean, that the important thing is, to be able to use the various
programs immediately.
</P>
<P>
Then if you want to do the more complex things with the program, use
level 2, 3, 4 or 5.
<EM>smile a lot</EM> ( I think, that even my older sister would be able to
understand!)
</P>
<P>
If you can get lots of people going surfing the Internet and writing
letters, as a minimum, using Linux, maybe a part of them slowly will
begin digging into other parts of Linux. And that would be good, at
least I think so!  
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)" 
		height="24" width="20" align="middle">
Maybe, even that was your ultimate goal?
</P>
<P>
Sorry, if I repeat something, but I am old.
Kind regards
A grass root, who hope to saw just a tiny seed   <em>still -laughing -
positive - friendly</em>
<br>September 2002.
</P>
<P>
Please do not reply, thank you  
<IMG SRC="../gx/dennis/smily.gif" ALT=":-)" 
		height="24" width="20" align="middle">
</P>

<!-- end 1 -->
<!--     .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.     -->
<P> <A NAME="wanted/2"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">PC-MOS</FONT></H3>
Mon, 16 Sep 2002 12:36:20 -0700
<BR>Derek Isbell (<a href="mailto:linux-questions-only@ssc.com?cc=linux-questions-only@ssc.com&cc=derek@holladays.com&subject=%20Re%3A%20%5BLG%2083%5D%20help%20wanted%20%232%20PC%20MOS">derek from holladays.com</a>)


<P><STRONG>
This is a multi-part message in MIME format.
</STRONG></P>
<P>
[argh.  stop that, it's a serious waste of bits. For a oneliner question
you just sent 3 extra email header lines, and a stack of HTML.]
</P>
<P><STRONG>
Where can i find myself a copy of PC-MOS?
</STRONG></P>
<P>
We don't know.   The fact that the Answer Guy, Jim Dennis, took a best
shot at poking around the internet a number of years ago, to answer a
question about it, is the best we've got.  PC-MOS itself appears to have
disappeared and all that remains may well be all the search engine
entries that point to our dusty little tidbits on the topic.
</P>
<P>
But if you've got a Linux question, or you got a thing you were trying
to do with PC-MOS and wonder if some flavor or other of Linux is up to
doing that for you... please, feel free to ask in more detail!
</P>

<!-- end 2 -->
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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">Minimal Linux (Redhat 7.2) Installation</FONT></H3>
Tue, 24 Sep 2002 10:28:23 -0700 (PDT)
<BR>V Sreejith (<a href="mailto:linux-questions-only@ssc.com?cc=sree707@yahoo.com&subject=%20Re%3A%20%5BLG%2083%5D%20help%20wanted%20%233minidisc%20RH">sree707 from yahoo.com</a>)


<P>
I have a 40 GB hard disk.
I have Redhat 7.2 installed
with all the features on the hard
disk taking about 2GB.
I used the grub boot loader.
</P>
<P>
Now I have done a minimal redhat(7.2) installation
on my hard disk.I could not go below 275
mb though.
I edited my old grub.conf
that is with the first installation and
added this new redhat minimum installation
paths.
</P>
<P>
During the boot when i select minimum version
i got an error saying bios wasn't able
to reach my new installation because of
the cylinder limit.
So I made a work around by specifying
the boot of the old installation(
both of them are same versions)
and changed the root to my new installation.
This worked and i was able to boot into my
new installation.
</P>
<P>
Now after booting into my new minimum installation
i deleted all the docs and man pages and further
reduced my installation size from 250 mb
to about 135 mb.
After this i used the dd command to image
the new installation to another linux partition
which i created and having a size of only 200mb.
I copied only the first 135 mb
from the source partition to the target partition.
</P>
<P>
I added another label in grub.conf to point
to this partition and tried to boot.
But after some initialisation messages
it stopped after showing the message kernel panic.
I saw a message stating that "attempt
to access block beyond reach" and showed
the block limit on the partition and
the block which was tried to access.
Obviously the block it was trying to
access was beyond the limit.
</P>
<P>
I am doubting whether this is some kind of
fragmentation problems.Whether the first 135
mb of the source disk
doesn't contain all the installed data.
Could it be that this data is scattered
all over this partition and i cannot image it
directly into another partition.
If that is the case what can i do about this?
Is there any defragmentation tools available
under linux?
</P>
<P>
My aim is to reduce the linux installation
size and to make an image of this reduced
installation on a seperate 200 mb disk
and to be able to boot  and work on it.
</P>
<P>
I actually don't know whether this method
works.This is a sort of experimentation.
</P>
<P>
Are there any other way of achieving this aim?
</P>
<P>
thanx
</P>
<P>
sree
</P>

<!-- end 3 -->
<!--              . . . . . . . . . . . . . . . . . . .              -->
<HR WIDTH="75%" ALIGN="center">
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">U of Phoenix</FONT></H3>
Fri, 30 Aug 2002 06:40:10 -0500
<BR>Pat Norton (<a href="mailto:linux-questions-only@ssc.com?cc=linux-questions-only@ssc.com&cc=nortonpc@email.uophx.edu&subject=%20Re%3A%20%5BLG%2083%5D%20help%20wanted%20%234%20U%20of%20Phoenix">nortonpc from email.uophx.edu</a>)


<P><STRONG>
Tue, 13 Feb 2001 10:00:12 -0500
<br>K.Woodward (kwoodwar from mindspring.com)
</STRONG></P>
<P><STRONG>
Hi,
</STRONG></P>
<P><STRONG>
I have a problem trying to setup Linux to access the servers at the
University of Phoenix. The servers (Microsoft IIS) require a "log on
using Secure Password Authentication" under Microsoft Outlook Express. I
understand that this requires a email and news reader to authenticate
using the WindowsNT Challenge/Response (NTCR) protocol [a really bad use
of the http protocol]. The school does have a website to get to the
email and news groups but it is timed and is very particular and seems
to like rejecting Netscape Navigator access. The UOP Tech group's pat
answer is that they only support Outlook Express under Windows, I want a
Linux answer.
</STRONG></P>
<P><STRONG>
Is there any program or daemon that I could run to allow me to
authenticate using this protocol so I could use Linux based email and
news readers? I have tried using pine, staroffice, and leafnode and
several others which are common under <A HREF="http://www.kde.org/">KDE</A>/RedHat 6.2.
</STRONG></P>
<P><STRONG>
Thanks,
</STRONG></P>
<P><STRONG>
K. Woodward
</STRONG></P>
<P>
I am using linux to try to connect to UOP now and have not found an
answer to the problem that you had did you ever find a solution that
worked if you did could you outline it for me.
</P>
<P>
Thank you,
<BR>Pat Norton
</P>
<P>
<A HREF="mailto:nortonpc@email.uophx.edu"
	>nortonpc@email.uophx.edu</A>
</P>
<P>
<A HREF="mailto:nortonpc1@cvol.net"
	>nortonpc1@cvol.net</A>
</P>

<!-- end 4 -->

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	><strong>[LG 82] 2c Tips #2  completion</strong></a>
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	><strong>How about Jed?</strong></a>
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</UL>
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<P> <A NAME="mailbag/1"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">[LG 82] 2c Tips #2  completion</FONT></H3>
Wed, 04 Sep 2002 16:58:19 +0700
<BR>Bill Thompson (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2083%5D%20mailbag%20%231%20completion">billt from samart.co.th</a>)



<P>
Adam,
</P>
<P>
The site for this Tip doesn't appear to be up any more.
Do you have an alternate source or can send me the rpm
or the source rpm?
</P>
<P>
Thanks,
</P>
<P>
Bill Thompson
</P>
<P><em>
I (the LG editor) was unable to reach that link when I was proofreading
2-Cent Tips ("connection timed out"), but I was hoping it was a temporary
error.  We at LG do not have any alternate sources or RPMs.  Maybe
Adam who submitted the tip does.
-- Mike</em></P>

<blockquote><font color="#000066">I usually go poking around for them on rpmfind.net if I know some file
they contain, or on freshmeat.net if I know the name of the project, in
the hopes of finding whatever upstream source tree might remain.
Sometimes I can find out why there's not an rpm anymore, but that's
pretty rare.
 -- Heather</font></blockquote>

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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">How about Jed?</FONT></H3>
Thu, 5 Sep 2002 09:34:07 +0200
<BR>Grabu&ntilde; &pound;ukasz (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2083%5D%20mailbag%20%232%20Jed">l.grabun from arr.gov.pl</a>)


<P><STRONG>
First of all: LG is great! One of the best newsletters (?) I've ever read.
Easy to browse webpage, understandable language, various topics. Great, just
great.
</STRONG></P>
<P><STRONG>
There's just one thing I'm missing: there was a column for Emacs - fans, a
nmber of articles about vim, even nano was mentioned. And what about jed?
It's as powerful and customizable as emacs, but much lighter and easier to
use. Will there be a few lines about this great tool?
</STRONG></P>
<P><STRONG>
regards,
<BR>Lukasz Grabun
</STRONG></P>
<P>
We'd be happy to publish an article on jed if somebody volunteers to write
it.  Would you?  The Author Information at
<A HREF="../faq/author.html"
	>http://www.linuxgazette.com/faq/author.html</A>
shows the desired HTML format.
</P>

<!-- end 2 -->
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<P> <A NAME="mailbag/3"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">Penguins, Lizards, and Pandas?</FONT></H3>
Mon, 23 Sep 2002 10:38:12 -0400 (EDT)
<BR>Virtual Sky Media Group (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2083%5D%20mailbag%20%233%20Windowmaker%20panda">virtualsky_sk from yahoo.ca</a>)



<P>
I'm proud to say that I've been a Linux user since
July 2002 and I've enjoyed my new found computing
freedom very much.  I've also learned a lot, too.
</P>
<P>
I began my Linux experience with my purchase of
Mandrake 8.2, a great distro. for a beginner, like
myself.  I also started out using <A HREF="http://www.kde.org/">KDE</A> as my desktop
manager, but have now found new liberties with the use
of Window Maker.  Which brings me to my submission to
you today.
</P>
<P>
Linux itself has the wonderful Tux as its
representative.  KDE has a dragon-like lizard, and
Gnome has a footprint of a gnome, I'm assuming.  After
reading from the Window Maker web site, I learned that
Window Maker has chosen a Panda as it's mascot.  So, I
decided to make a contribution to the line up of cute
and cuddly cartoon PR "toons" with this
drawing of Amanda, the Window Maker panda:
<BR>
<img src="misc/mail/WM_Panda2-small.png"
	alt="[cute Windowmaker panda]"
	HSPACE="20" VSPACE="20">
</P>
<P><em>
Oh, that's soooo cute! A panda with an attitude. <TT>/me</TT> likes. 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle">
-- Ben</em>
</P>
<P>
Now, don't you just want to start using Window Maker?
:o)
</P>
<P><em>
Nope. 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle"> But then, I'm an "icewm" junkie from way back.
</em></P>
<P><em>
I think I'll have to lobby Marko Macek for a mascot now.
-- Ben</em>
</P>
<P>
Keep the very informative issues of Linux Gazette
coming!  I enjoy them very much.
</P>
<P>
David Bouley
</P>
<P><em>
Glad you like'em, David! Stick around; there's always more good stuff in
the works.
-- Ben</em>
</P>
<P>
An explanation sidebar might be inline about what a PNG is, why GIF,
and now JPEG, are Bad Ideas, and why Internet Exploiter 5 doesn't know
how to deal with PNG's.  At least not as URLs; maybe it gets them right
as inlines...
-- jra
</P>
<P><em>
The only problem I've seen with PNG is that Netscape 4 displays a solid filled
rectangle instead of the image <EM>if</EM> the image contains any transparency.
</em></P>
<P><em>
As for JPG, I've heard conflicting information on whether any patent applies to
it, but the last I heard was that there wasn't a problem.  Have you heard
differently?
--  Nike</em>
</P>
<P><em><b>
JPEG is fine.  The so-called JPEG patent is bogus, and if Forgent
tries to use it, they will lose it (like BT and the hyperlink patent)
(This is from the leading <EM>defender</EM> of software patents, Greg
Aharonian: <A HREF="http://www.aful.org/wws/arc/patents/2002-07/msg00029.html"
	>http://www.aful.org/wws/arc/patents/2002-07/msg00029.html</A>)
</b></em></P>
<P><em><b><DL><DT>
PNG support in browsers (inluding MSIE) is "quite good":
<DD><A HREF="http://www.libpng.org/pub/png/pngstatus.html#browsers"
	>http://www.libpng.org/pub/png/pngstatus.html#browsers</A>
</DL></b></em></P>
<P><em><b>
(Linux Journal has been using PNG instead of GIF since our redesign last
year, and there have been no complaints.)
-- Don</b></em>
</P>

<blockquote><font color="#000066">And of course, Don ought to know, since he cheerfully burns all GIFs.
(<A HREF="http://www.burnallgifs.org"
	>http://www.burnallgifs.org</A>)  It's a good site to check on why a number
of patents out there are really quite foolish.
 -- Heather</font></blockquote>
<P><em>
In any case, PNG and JPG have quite different uses.  PNG is good at compressing
line art but bad at compressing things with lots of colors (e.g., photographs),
whereas for JPG it's the reverse.  Whenever somebody sends a GIF to LG, I convert
it to both PNG and JPG, and take whichever one has the best compromise of small
size and color brilliance.  It's not always one or always the other.  Sometimes
the sizes are hugely different, as in one being four times the size of the other.
-- Mike</em></P>

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<HR WIDTH="75%" ALIGN="center">
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">Thank you!</FONT></H3>
Thu, 19 Sep 2002 14:54:05 -0500
<BR>Bryan Lord (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2083%5D%20mailbag%20%234%20thanks%20101">blord from wlgroup.com</a>)


<P>
I read your article "Routing &amp; Subnetting 101", and... wow!  I listened to my
teacher ramble on for almost 3 hours and I didn't absorb a darn thing.
By reading your article I think I know enough to really get my hands dirty.
</P>
<P>
Thanks, Again.
<br>Bryan Lord
</P>

<!-- end 4 -->

<HR>
<center>
<BIG><STRONG><FONT COLOR="maroon">GAZETTE MATTERS</FONT></STRONG></BIG>
<BR>
</center><HR>
<UL>
<!-- index_text begins -->
<li><A HREF="#gaz/1"
	><strong>Questions to linux-questions-only@ssc.com and linux-questions-only@ssc.com</strong></a>
<li><A HREF="#gaz/2"
	><strong>bridging and routing</strong></a>
<li><A HREF="#gaz/3"
	><strong>(no subject)</strong></a>
<li><A HREF="#gaz/4"
	><strong>Pl give solution</strong></a>
<li><A HREF="#gaz/5"
	><strong>Letter of inquiry</strong></a>
<li><A HREF="#gaz/6"
	><strong>ssc subscription</strong></a>
<li><A HREF="#gaz/7"
	><strong>How to Ask a Question</strong></a>
<!-- index_text ends -->
</UL>
<!--     .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.     -->
<P> <A NAME="gaz/1"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">Questions to linux-questions-only@ssc.com and linux-questions-only@ssc.com</FONT></H3>
Wed, 4 Sep 2002 10:44:33 -0700
<BR>Heather Stern (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2083%5D%20gazette%20matters%20%231%20aliases"><em>Linux Gazette</em> Technical Editor</a>)


<P><dl><dt>
This is a reminder that although the aliases:

<dd><A HREF="mailto:linux-questions-only@ssc.com"
	>linux-questions-only@ssc.com</A>
<DT>
and:
<DD><A HREF="mailto:linux-questions-only@ssc.com"
	>linux-questions-only@ssc.com</A>
</DL></P>
<P><DL><DT>
work, the real address of the Linux Gazette Answer Gang is:
<DD><A HREF="mailto:linux-questions-only@ssc.com"
	>linux-questions-only@ssc.com</A>
</DL></P>
<P>
We're working towards getting all sites that mention us to give the
correct address, and to get them to not mention us if they suggest we
cover anything that's not about computers.
</P>
<P>
Please spread the word!
</P>

<!-- end 1 -->
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<P> <A NAME="gaz/2"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">bridging and routing</FONT></H3>
Mon, 9 Sep 2002 11:43:31 -0700
<BR>Mike Orr (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2083%5D%20gazette%20matters%20%232%20anon"><em>Linux Gazette</em> Editor</a>)



<!-- sig -->

<P><STRONG><FONT COLOR="#000066"><EM>
Please do not publish my email address; I will read the Gazette for any
responses.
</EM></FONT></STRONG></P>
<P><STRONG>
Email address will not be published.  It shows up in this correspondence,
but there's no public archive of this list.
</STRONG></P>
<P>
We do publish addresses for Mailbag items and 2-Cent Tips, but not for Answer
Gang questions.  That's Heather's choice as the TAG Editor Gal.  If I were
doing it I'd publish addresses in the Answer Gang column too, because why
should that column be different?  In any case, you don't know which of the
three columns your letter might appear in.  A lot of it has to do with whether
it produces one or two short replies or a long discussion.
</P>
<P>
So the only way a reader can guarantee his/her address won't be published
is to specifically ask us not to.
</P>
<P>
-- Mike
</P>

<blockquote><font color="#000066">Originally, the Answer Guy column was purely the answers of Jim, but as
it changed, The Answer Gang column is now about matters which have
pretty much been solved, or discussed to death in some fascinating way.
Therefore unless the original querent's problem remains unsolved -- a
real stumper -- there's little need to provide his or her email address,
but we do mention the name.
</font></blockquote>
<blockquote><font color="#000066">In the case of Tips other people may have useful comments, so the
address is offered.
</font></blockquote>
<blockquote><font color="#000066">Unless, of course, they'd like to be anonymous.
</font></blockquote>
<blockquote><font color="#000066">People do not get selected for Help Wanted if they wish to be anonymous.
You can't beg a few thousand readers for help that way.  They just have
to have a complete and interesting  enough description to tantalize one
of the Gang to answer them.
 -- Heather</font></blockquote>

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<P> <A NAME="gaz/3"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">(no subject)</FONT></H3>
Tue, 24 Sep 2002 07:14:02 +0530
<BR>anonymous (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2083%5D%20gazette%20matters%20%233confidential"></a>)


<!-- sig -->

<P>
[ An 8 line sig block claiming confidentiality, erased per its
instructions. ]
</P>
<P>
Must be confidential indeed;  it didn't say anything but this!
</P>
<P>
This mailing list (The Linux Gazette Answer Gang, which makes its home
at <A HREF="mailto:linux-questions-only@ssc.com"
	>linux-questions-only@ssc.com</A>) is not a confidential location.  It is
a mailing list filled with a medium sized handful of Linux folk, who
expect as their main pay a bunch of warm fuzzies and the knowledge that
a really juicy answer can be published for the readers of our monthly
magazine.  Opinions are likely to run rampant, conclusions may or may
not occur (we guarantee nothing) and attachments in HTML are often
ignored or grumbled about unless you're defending a foreign character
set (yes, we have translators).  It's a good idea to actually dust off
your sense of humor because we definitely use ours.
</P>
<P>
If you need an answer in some business-like fashion, you'll have to
consider a consultant instead.  LinuxPorts has a good list of them.
</P>
<P>
If you want an answer in a "Making Linux a Little More Fun" fashion
you'll at <EM>least</EM> need to provide us a real question, and if this
sig block of yours is automatic, a disclaimer that supercedes it and
grants publishing permission.  We have examples in our "Ask The Gang"
FAQ;  see <A HREF=".."
	>http://www.linuxgazette.com</A> for more.  Lots more 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle">
</P>
<P>
Your HTML attachment has been sent to the shredder;  it wanted a snack
and we won't be passing out candy for almost a <EM>month</EM> !
</P>

<!-- end 3 -->
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<P> <A NAME="gaz/4"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">Pl give solution</FONT></H3>
Wed, 18 Sep 2002 09:57:06 +0200
<BR>Frank Rodolf (<a href="mailto:gazette@ssc.com?cc=chothmal_c@yahoo.com&subject=%20Re%3A%20%5BLG%2083%5D%20gazette%20matters%20%234%20homework">linux from rodolf.com</a>)
<BR>Question by choudhary chothmal (chothmal_c from yahoo.com)


<P>
Hi choudhary,
</P>
<P><STRONG>
Dear sir,
Pl give sol these problem
1
Write a shell script to print end of a glossary file,
in reverse order . using array (Hint use awk ,tail )
</STRONG></P>
<P><STRONG>
Q-2 Modify call command to accept more than one month?
Q-3 Write a shell script to print file names one per
line has directory showing serial number of file
</STRONG></P>
<P>
I see schools have started again...
</P>
<P>
While we're perfectly willing to help you with any questions you have
about Linux, we will NOT help you with your homework.
</P>
<P>
I am sure you will find all the info to solve the problems in the
textbook(s) your professor gave you (or had you buy). It (they) might be a very
interesting read - just try it.
</P>
<P>
Grtz,
</P>
<P>
Frank
</P>

<!-- end 4 -->
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<P> <A NAME="gaz/5"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">Letter of inquiry</FONT></H3>
Thu, 19 Sep 2002 02:16:09 -0700 (PDT)
<BR>dang mangaoang (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2083%5D%20gazette%20matters%20%235%20inquiry">jomegs143 from yahoo.com</a>)



<P><STRONG>
Dear Sir,
</STRONG></P>
<P><STRONG>
I am writing this letter to inquire about your product <A HREF="http://www.redhat.com/">Red Hat</A>
Linux.   I saw Red Hat Software's advertisement . . .
</STRONG></P>

<blockquote><font color="#000066">Red Hat is a company of its own;  you should follow contact
information provided in the advertisement.
 -- Heather</font></blockquote>
<P><em>
Try
<br><A HREF="http://www.redhat.com"
	>http://www.redhat.com</A>
-- Dan Wilder
</em></P>
<P>
We don't make Linux, we just blather about it.
</P>
<P>
See
<br><A HREF="http://www.redhat.com"
	>http://www.redhat.com</A> as well as
<br><A HREF="http://www.linux.org"
	>http://www.linux.org</A> and probably
<br><A HREF="http://www.li.org"
	>http://www.li.org</A> not to mention
<br><A HREF="http://www.tldp.org"
	>http://www.tldp.org</A>
</P>
<P>
-- jra
</P>
<P><STRONG>
. . . for version 5.1 of Linux in the issue of Linux Journal.
</STRONG></P>

<blockquote><font color="#000066">That's an interesting case of time travel you have there;   you've
reached the <i>Linux Gazette</i>, which is a related pubication in that we're
hosted by the same publishing company.
</font></blockquote>
<blockquote><font color="#000066">Red Hat 5.1 is quite ancient...
 -- Heather</font></blockquote>
<P>
RedHat is up to 7.3 in production release, and there's a beta 7.4 out
there somewhere, I think, rotting people's cats' teeth.
-- jra
</P>

<blockquote><font color="#000066">They [Red Hat] are
mirrored in a number of countries so it should be possible to find an
instance of the 7.2 "GPL edition" disc on servers nearer to you.  Beware
that downloading 650 MB can take a while, though.
 -- Heather</font></blockquote>
<P><STRONG>
I was quite impressed with the capabilities
as listed in the advertisement, and I would like to learn some more
about the product. I am a student and we are studying about Linux and
this is the reason why I want to learn more about the product.
</STRONG></P>

<blockquote><font color="#000066">Running older versions of Linux for experimental purposes, or studying
what was claimed of Linux a few years ago to see how it has grown, are
both valid student projects.
 -- Heather</font></blockquote>
<P><STRONG>
another thing is I want to subscribe a magazine about linux operating
system.
</STRONG></P>

<blockquote><font color="#000066">In that case you came to the right place, almost :D
</font></blockquote>
<blockquote><font color="#000066">I cheerfully direct you to the website for Linux Journal,
	<A HREF="http://www.linuxjournal.com"
	>http://www.linuxjournal.com</A>
where you can use a secure connection to subscribe, or find more
information about having it sent to you monthly.
</font></blockquote>
<blockquote><font color="#000066">Linux Gazette is only available as a webzine although that leads to some
unusual "subscription" models in the form of Sitescooper, debian
packages (lg-subscription), and services that can tell you when a
website changes.  These features are not provided by staff of the
Gazette but rather, by volunteers elsewhere.
 -- Heather</font></blockquote>
<P><STRONG>
Hope you could reply me as soon as possible.
</STRONG></P>
<P><STRONG>
Sincerely yours,
</STRONG></P>
<P><STRONG>
Dang
</STRONG></P>

<blockquote><font color="#000066">Hope you found this useful!
</font></blockquote>
<blockquote><font color="#000066">Thank you, and enjoy Linux.
 -- Heather</font></blockquote>

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<P> <A NAME="gaz/6"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">ssc subscription</FONT></H3>
Mon, 02 Sep 2002 09:18:37 -0700
<BR>John R. Sowden (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2083%5D%20gazette%20matters%20%236%20email%20subscription">jsowden from americansentry.net</a>)



<P><STRONG>
I subscribe to various linux/dos/security/pascal/xbase lists, so knowing
what "ssc" is is somewhat difficult.  Once a month you send me a reminder
to make sure I still want to subscribe.  Please consider describing the
various subscriptions, including other ones that might be of interest.
</STRONG></P>
<P>
SSC is Specialized Systems Consultants, Inc, the company that
publishes Linux Gazette, the print magazine Linux Journal
(<A HREF="http://www.linuxjournal.com"
	>http://www.linuxjournal.com</A>), and books and reference cards
about Linux/Unix.  The message you get once a month is from our
mailing-list server, reminding you how to unsubscribe or change
your settings.  Other mailing lists we run are are at
<A HREF="http://www.ssc.com/mailman/listinfo"
	>http://www.ssc.com/mailman/listinfo</A>
and in the top right corner of <A HREF="http://www.linuxjournal.com"
	>http://www.linuxjournal.com</A> .
A few are discussion lists, but most are announcement-only lists
(newsletters).
</P>
<P>
-- Mike
</P>

<!-- end 6 -->
<!--              . . . . . . . . . . . . . . . . . . .              -->
<HR WIDTH="75%" ALIGN="center">
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/envelope.gif">
<FONT COLOR="navy">How to Ask a Question</FONT></H3>
Fri, 30 Aug 2002 09:48:01 -0400 (EDT)
<BR>Naresh (<a href="mailto:gazette@ssc.com?subject=%20Re%3A%20%5BLG%2083%5D%20gazette%20matters%207%23how%20to%20ask">nganta from myrealbox.com</a>)

<P><STRONG>
How can I ask a question to the answer gang?
</STRONG></P>
<P><STRONG>
Naresh
</STRONG></P>

<blockquote><font color="#000066">Send your note to the address:
	<A HREF="mailto:linux-questions-only@ssc.com"
	>linux-questions-only@ssc.com</A>
</font></blockquote>
<blockquote><font color="#000066">Make your subject a useful one.
</font></blockquote>
<blockquote><font color="#000066">Make your description of what you're trying to do, and
what is going wrong, sufficiently detailed and interesting
that some of the gang can answer it.
</font></blockquote>
<blockquote><font color="#000066">We might answer in a big burst, or after a long time, or
not at all.  A small portion of the "not at all" get pubbed
as Help Wanted and readers from all over the world may give
those a shot - but for that the description does have to be
pretty clear.
</font></blockquote>
<blockquote><font color="#000066">We've more details in the Linux Gazette FAQs.
</font></blockquote>
<blockquote><font color="#000066">Good luck!
 -- Heather</font></blockquote>

<!-- end 7 -->
<P> <hr> </p>
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
<h5>This page edited and maintained by the Editors of <I>Linux Gazette</I><br>HTML script maintained by <A HREF="mailto:star@starshine.org">Heather Stern</a> of Starshine Technical Services, <A HREF="http://www.starshine.org/">http://www.starshine.org/</A>
<br>Copyright &copy; 2002
<br>Copying license <A HREF="http://www.linuxgazette.com/copying.html">http://www.linuxgazette.com/copying.html</A>
<BR>Published in Issue 83 of <i>Linux Gazette</i>, October 2002</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 WIDTH="380">


<center>
<BIG><BIG><STRONG><FONT COLOR="maroon">More 2-Cent Tips</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/.html"></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>Canon BJC 250</strong></a>
<li><A HREF="#tips/2"
	><strong>sendmail and Courier</strong></a>
<li><A HREF="#tips/3"
	><strong>Postfix hates Outlook</strong></a>
<li><A HREF="#tips/4"
	><strong>ping with ipmasq</strong></a>
<li><A HREF="#tips/5"
	><strong>multilink</strong></a>
<li><A HREF="#tips/6"
	><strong>power management</strong></a>
<li><A HREF="#tips/7"
	><strong>Adding Win98 to a second HD</strong></a>
<li><A HREF="#tips/8"
	></a>MDaemon Warning - Virus Found --or--
<br><A HREF="#tips/8"
	><strong>If You're Not Part of the Solution, You're Part of the Precipitate</strong></a>

<li><A HREF="#tips/9"
	><strong>autocad on linux</strong></a>
<li><A HREF="#tips/10"
	><strong>ringing a bell when compilation is finished</strong></a>
<li><A HREF="#tips/11"
	></a>RedHat 7.3 on Dell Inspiron 8100 Laptop --or--
<br><A HREF="#tips/11"
	><strong>Configuring the GUI, the GUI way</strong></a>

<li><A HREF="#tips/12"
	><strong>Diald problems again</strong></a>
<li><A HREF="#tips/13"
	><strong>dual boot with XP</strong></a>
<li><A HREF="#tips/14"
	><strong>Hiding SAMBA shares</strong></a>
<li><A HREF="#tips/15"
	><strong>recompiling the kernel with a X11 keymap</strong></a>
<li><A HREF="#tips/16"
	><strong>Linux multilanguage</strong></a>
<li><A HREF="#tips/17"
	><strong>Re: exe to iso files</strong></a>
<li><I>Linux Journal's</I> Weekly News Notes 
	<a href="#tips/lj">Tech Tips</a>
	<ul>
	<LI>Keeping NAT connections alive
	<li><A HREF="http://noframes.linuxjournal.com/subscribe/lja-sub.html"
		>subscribe</A> to LJWNN
	</ul>
<!-- index_text ends -->
</UL>
<!--     .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.     -->
<P> <A NAME="tips/1"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Canon BJC 250</FONT></H3>
Sun, 15 Sep 2002 12:08:39 -0700
<BR>dfox (<a href="mailto:linux-questions-only@ssc.com?cc=dfox@m206-157.dsl.tsoft.com&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%231">dfox from m206-157.dsl.tsoft.com</a>)



<!-- sig -->


<!-- sig -->

<P>
Regarding Bessie's problem in the sept. 2002 issue of LG (Help Wanted
#1):
<A HREF="../issue82/lg_mail.html#wanted/1"
	>http://www.linuxgazette.com/issue82/lg_mail.html#wanted/1</A>
</P>
<P>
I also have one of these printers, and it has worked nicely, at least for
monochrome. I have done limited color testing - early on, it would print in
color if I selected a different printer driver at that time (bj 200 is only
capable of doing monochrome). Colors were somewhat washed out, and i never
got around to really testing things like gamma correction. Besides, that was
some time ago, before cups et al.
</P>
<P>
I sent bessie an email asking if she were using cups. There is a little
difference in the revs of cups at least with Mandrake 8.1 which is what I'm
currently running. If I use printerdrake, i am able to select a bj200 driver,
which is perfect for doing monochrome printing, and the test page prints just
fine. If i use another printer configuration tool, there is no corresponding
entry for my printer. However, selecting a similar model driver is doable if
the exact model is not listed -- and seemingly in (how?) recent cups it is
not. And seemingly, there are different printer databases. (i built cups
1.1.10 I think sometime ago from source).
</P>

<!-- end 1 -->
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<P> <A NAME="tips/2"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">sendmail and Courier</FONT></H3>
Thu, 5 Sep 2002 07:45:51 -0700
<BR>Dan Wilder (<a href="mailto:linux-questions-only@ssc.com?cc=linux-questions-only@ssc.com,&cc=dan@ssc.com&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%232">dan from ssc.com</a>)



<!-- sig -->


<!-- sig -->


<blockquote><font color="#000066">This is in regards to September's help wanted #2:
	<A HREF="../issue82/lg_mail.html#wanted/2"
	>http://www.linuxgazette.com/issue82/lg_mail.html#wanted/2</A>
 -- Heather</font></blockquote>
<P><STRONG>
Hi,
</STRONG></P>
<P><STRONG>
First, you'll have a problem using sendmail and maildir, since, sendmail
does not support maildir, only qmail and postfix support this. If you've a
</STRONG></P>
<P>
However, consider using procmail as the local delivery agent.  I believe
sendmail will support this, though I should mention I haven't used
sendmail for quite a few years.  Anyway, procmail supports maildir
delivery.
</P>
<P>
-- Dan Wilder
</P>

<blockquote><font color="#000066">A different reader seemed to believe that sendmail cannot, only postfix
and qmail -- but yet another reader chimed in that it's the default on
his distro for sendmail to use procmail as its local delivery, after
which it's of course no problem.  Sadly they had confidentiality notes
on their mails, so no juicy details.  Sorry.
 -- Heather</font></blockquote>

<!-- end 2 -->
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<P> <A NAME="tips/3"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Postfix hates Outlook</FONT></H3>
Sat, 07 Sep 2002 01:33:43 -0500
<BR>Dustin Puryear (<a href="mailto:linux-questions-only@ssc.com?cc=dustin@puryear-it.com&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%233">dustin from puryear-it.com</a>)



<!-- sig -->


<!-- sig -->


<blockquote><font color="#000066">This is for help wanted #3 in September's issue:
	<A HREF="../issue82/lg_mail.html#wanted/3"
	>http://www.linuxgazette.com/issue82/lg_mail.html#wanted/3</A>
 -- Heather</font></blockquote>
<P>
Determine if the mail server is trying to perform reverse resolution for
your IP address. This can lead to odd time-out problems with various
services. A quick test is to add a mapping for your IP address to the mail
server's <TT>/etc/hosts</TT> and see if the problem goes away.
</P>
<P>
Regards, Dustin
</P>
<HR width="10%" align="center"><P>
From: SnT_BaBS &lt;<A HREF="mailto:babs@sntteam.org"
	>babs@sntteam.org</A>&gt;
</P>
<P>
I think that u can't access root account with pop3 server for security reason ...
</P>
<P>
Maybe i'm wrong ... but it can be ...
</P>
<P>
Regards 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle">
</P>

<blockquote><font color="#000066">Babs here has to at least be partly right.  Postfix doesn't speak POP3
-- it speaks SMTP!  Common pop3 servers include qpopper, solidpop,
or ipop3d.
 -- Heather</font></blockquote>

<!-- end 3 -->
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<P> <A NAME="tips/4"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">ping with ipmasq</FONT></H3>
Mon, 02 Sep 2002 11:12:44 -0700
<BR>David Ranch (<a href="mailto:linux-questions-only@ssc.com?cc=dranch@trinnet.net&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%234">dranch from trinnet.net</a>)



<!-- sig -->


<!-- sig -->


<blockquote><font color="#000066">This is in reply to the September 2002 help wanted #4:
	<A HREF="../issue82/lg_mail.html#wanted/4"
	>http://www.linuxgazette.com/issue82/lg_mail.html#wanted/4</A>
 -- Heather</font></blockquote>
<P>
Hello Matt and LG,
</P>
<P>
My name is David Ranch and I am the author of the IP Masquerade HOWTO
as well as the TrinityOS documentation project.
</P>
<P>
Anyway, regarding your eth0/eth1 issue, have you checked the DUPLEX
setting on the Ethernet switch?  The tell-tale signature of this
is the "carrier" transitions in your "ifconfig' output.  Since you
have a switch and not a dual-speed hub, make sure it's set to FULL
DUPLEX for that port connected to eth1.  You also might want to
force the speed on that port to 100 as well.  Ethernet auto-negotiation
has always been a problem.
</P>
<P>
If that doesn't fix things, do you have a different Ethernet card
to try?  Personally, I think all LNX* network cards are pretty crappy
though they do work.  I've had great luck with any Tulip-based network
card (Netgear FA310 [not the 311, etc]), Intel EtherExpress, etc.
</P>
<P>
Ps.  The comment from Heather at the bottom of
</P>
<P>
<A HREF="../issue82/lg_mail.html#wanted/4"
	>http://www.linuxgazette.com/issue82/lg_mail.html#wanted/4</A>
</P>
<P>
is plain wrong.  The IPMASQ code has supported ICMP MASQ since
the Linus kernel 1.2 days (possibly earlier).
</P>
<P>
--David
</P>

<blockquote><font color="#000066">In fact, I did see some references to it behaving correctly - later -
but never have figured out why it wouldn't work in real life while I was
dealing with it.  Which means that while it's surely supported, if I'm
in a situation on a 2.2.x kernel where ICMP is not working past NAT, I
have no idea how to convince it to start working.
</font></blockquote>
<blockquote><font color="#000066">Oh well, we all have our specialties;  I'll go back to tweaking X
displays and tuning up laptops, now.
</font></blockquote>
<blockquote><font color="#000066">I absolutely agree that the Tulip chipset is the good stuff.  Never
leave home without it.
 -- Heather</font></blockquote>

<!-- end 4 -->
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<P> <A NAME="tips/5"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">multilink</FONT></H3>
Mon, 02 Sep 2002 13:19:44 -0700
<BR>David A. Ranch (<a href="mailto:linux-questions-only@ssc.com?cc=dranch@trinnet.net&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%235">dranch from trinnet.net</a>)



<!-- sig -->


<!-- sig -->

<P>
Hello John, LG,
</P>
<P>
My name is David Ranch and I am the author of the
IP Masqeurade HOWTO as well as the TrinityOS
guide.
</P>
<P>
Anyway, I saw your LG question:
</P>
<P><BLOCKQuote>
<A HREF="../issue82/lg_mail.html#wanted/5"
	>http://www.linuxgazette.com/issue82/lg_mail.html#wanted/5</A>
</BLOCKQuote></P>
<P>
First off, one of the posters mention that EQL is the
solution.  This is incorrect as EQL is rarely
supported any other terminal servers than possibly
older Livingston Portmaster.  Like you mentioned,
you want MultiLink PPP.
</P>

<blockquote><font color="#000066">Oops, I thought they were one and the same.  Thanks for pointing out my
misconception.
-- John Karns
 -- Heather</font></blockquote>
<P>
Before you start looking into setting this up,
you should call your ISP and see if they allow
ML-PPP?  Many don't and the few that do usually
only support it for ISDN users.
</P>

<blockquote><font color="#000066">Good point, one which I forgot to make.
-- John
 -- Heather</font></blockquote>
<P>
Anyway, here are some URLs that should help you
in your MLPPP quest if your ISP does infact support
ML-PPP for dialup users.
</P>
<P>
<A HREF="http://www.google.com/search?hl=en&amp"
	>http://www.google.com/search?hl=en&amp</A>;ie=UTF-8&amp;oe=UTF-8&amp;q=setting+up+multilink+ppp+on+linux&amp;btnG=Google+Search
</P>
<P>
--David
</P>

<blockquote><font color="#000066">And thanks for the URL's.
-- John
 -- Heather</font></blockquote>

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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">power management</FONT></H3>
Tue, 17 Sep 2002 08:47:00 +0000
<BR>sgupta (<a href="mailto:linux-questions-only@ssc.com?cc=sgupta@pressroom.com&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%236">sgupta from pressroom.com</a>)



<!-- sig -->


<!-- sig -->

<P>
Hello.
</P>
<P>
My new PC running Linux has the new Intel motherboard that supports only
ACPI, not APM.  I understand from the vendor that Linux does not support
ACPI as yet.  Hence, I can't put my machine in stand-by or sleep mode.
The only solutions are to keep it running (room temperature gets high
during day time ~80 degrees) or power off.
</P>
<P>
Is Linux planning to support ACPI any time soon? Are there other
alternatives to power off? After all, one of the best advantages of Linux
is that you don't need to boot it every time you want to use the machine.
It can run for a long time without crashing.
</P>
<P>
Thanks.
<BR>SG
</P>
<BLOCKQUOTE>
[Ashwin N] 
Linux <EM>has</EM> support for ACPI in 2.4.x kernels. I suppose it wasn't there
in the older kernels.
</BLOCKQUOTE>
<BLOCKQUOTE>
You'll need to install/upgrade your Linux distribution/kernel.
</BLOCKQUOTE>
<P><STRONG>
Hello.
Thanks for the prompt reply. I guess the vendor knows less about Linux than I
do.  He installed RH 7.3 with kernel 2.4.18-3 on the PC, which as you say supports
ACPI. Unfortunately, it is not activated. In the directory <TT>/etc/rc.d/init.d</TT> I
can find apmd but not acpid. Do I have to reconfigure/recompile the kernel to get it
working.  I checked up all the Linux How-Tos and FAQs and can't find any information
about getting ACPI to work.
</STRONG></P>
<P><STRONG>
Thanks.
<BR>SG
</STRONG></P>
<BLOCKQUOTE>
[Rick Moen] 
Googling found this unofficial HOWTO:
<A HREF="http://www.columbia.edu/~ariel/acpi/acpi_howto.txt"
	>http://www.columbia.edu/~ariel/acpi/acpi_howto.txt</A>
</BLOCKQUOTE>
<BLOCKQUOTE><DL><DT>
It's linked from this summary page:
<DD><A HREF="http://mobilix.org/apm_linux.html"
	>http://mobilix.org/apm_linux.html</A>
</DL></BLOCKQUOTE>
<BLOCKQUOTE><DL><DT>
And perhaps you've already come across the ACPI 4 Linux Project:
<DD><A HREF="http://acpi.sourceforge.net"
	>http://acpi.sourceforge.net</A>
</DL></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">Adding Win98 to a second HD</FONT></H3>
Fri, 13 Sep 2002 21:57:46 +0300
<BR>Nigel Ridley (<a href="mailto:linux-questions-only@ssc.com?cc=linux-questions-only@ssc.com&cc=nigel@i-amfaithweb.net&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%237">nigel from i-amfaithweb.net</a>)



<!-- sig -->


<!-- sig -->

<P>
O.K. I know this is a lame one but I don't want to mess up!
</P>
<P>
My children are now of the age that they are fighting over whose turn it
is on the (old) computer - it has Windows 95 and (unfortunately) they like
some of the silly games that children love - namely Mario (no I haven't
found one to run under Linux).
</P>
<P>
So now I am under pressure to use my Linux box as a second Windows machine
to satisfy the children (no funds for even a second hand 'puter).
</P>
<P>
On my Linux box I have two hd's, one 20 GB - the main one and a second one
of 6 GB. I want to put Windows 98 on the second hd.
How do I make sure that Windows uses the second hd and not wipe out my
Linux one?
Also how do I rescue the mbr from Windows after the install? - I'm using
Mandrake 8.2 with Lilo.
</P>
<P>
Nigel Ridley
</P>
<BLOCKQUOTE>
[JimD] 
Take out the Linux drive.  Make it a slave.  Install the smaller
drive (as standalone at first).  Install Win '9x.  Change the smaller
drive to be the master (if necessary) and re-install the big drive.
(Leave a small non-DOS partition near the front of it if you can).
</BLOCKQUOTE>
<BLOCKQUOTE>
Now boot from a rescue CD or floppy specifying root=/dev/hdbX (as
appropriate) and add the appropriate entries for an "other" stanza
to your <TT>/etc/lilo.conf.</TT>  Then run <TT>/sbin/lilo</TT> to install a new MBR
on the little drive.
</BLOCKQUOTE>
<BLOCKQUOTE>
(The MBR on the big drive will be preserved, irrelevant until it's
put back into a system as a master or standalone).
</BLOCKQUOTE>
<BLOCKQUOTE>
You might not need to use that small non-DOS partition that you
created --- but I'd reserve it anyway (if the Win '9x installer will
let you).  You can boot from a Linux rescue disc or diskette to run
Linux fdisk and mark the small partition as OS/2 or with some sort
of hibernation volume type --- anything but Linux, since I hear that
newer Microsoft releases with eradicate Linux partitions with extreme
prejudice 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle"> .
</BLOCKQUOTE>
<BLOCKQUOTE>
There are undoubtedly a multitude of alternative approaches.  You
could use GRUB and it's notion of "hidden" drives (to swap the
identities of the two drives during the boot process, in memory).
You might be able to install it (standalone) and then make it the
slave (LILO) but I think MS Windows would get unhappy about not having
a C drive.
</BLOCKQUOTE>
<BLOCKQUOTE>
[John K.] 
If one is resigned to using sharing the system with the rogue OS, then the
above is another good reason to keep MSW straight-jacketed in an
environment such as a virtual machine where it can't do any damage to
things it has no business touching.
</BLOCKQUOTE>
<BLOCKQUOTE>
[JimD] 
I think John is thrying to suggest that you could use VMWare (or
Plex86 if you're daring, or <A HREF="http://www.winehq.com/">WINE</A>) to run Win '9x as a process under
Linux.
</BLOCKQUOTE>
<BLOCKQUOTE>
This works pretty well --- but has a few downsides that might
apply to you're needs:
</BLOCKQUOTE>

<blockQuote><ol>
<LI>VMWare needs lots of memory and plenty of CPU horsepower.
		   If you machine is older (less than about a 650Mhz Pentium II
		   or so) or doesn't have lots of memory (128Mb minimum, 512Mb
		   won't be wasted) then you may find this approach acceptable.


<LI>You might have relatively limited support for sound, USB
		   joysticks, etc.  You said you're kids are fighting over games
		   (IIRC) and Windows' rehosted under a virtual machine and
		   running a game is likely to be unpleasantly slow.


<LI>VMWare is pretty good as a product.  However it's not free
	 --  purchasing it will more than double your cost over buying
	 the requisite copy of Win '98.  Plex86 (FreeMWare) is free but
	 many not be up to the task of running the software you need nor
	 supporting your hardware.  It will certainly be more work (learning
	 curve) on your part.


<LI>You're kids may have to learn a little Linux/UNIX in order to get
     the VMWare (or other) virtual machine running and booted, possibly
	 switching it to full screen mode and sometimes (perhaps) get back
	 to it or out of it and back to the Linux host under various
	 possible situations.  You might make this all pretty transparent
	 (they log in via xdm/gdm/kdm etc, it starts the VM session and
	 then the just choose shutdown and they log back out).
</ol></blockQuote>
<BLOCKQUOTE>
However, it might be just what you're looking for.  Take a look at
these websites:
</BLOCKQUOTE>
<BLOCKQUOTE><DL><DT>
VMWare:
<DD><A HREF="http://www.vmware.com"
	>http://www.vmware.com</A>
</DL></BLOCKQUOTE>
<BLOCKQUOTE><DL><DT>
WINE:
<DD><A HREF="http://www.winehq.com"
	>http://www.winehq.com</A>
</DL></BLOCKQUOTE>
<BLOCKQUOTE><DL><DT>
CodeWeavers (WINE related):
<DD><A HREF="http://www.codeweavers.com"
	>http://www.codeweavers.com</A>
</DL></BLOCKQUOTE>
<BLOCKQUOTE><DL><DT>
TransGaming (WINEX):
<DD><A HREF="http://www.transgaming.com"
	>http://www.transgaming.com</A>
</DL></BLOCKQUOTE>
<BLOCKQUOTE><DL><DT>
Plex86 (FreeMWare):
<DD><A HREF="http://www.plex86.org"
	>http://www.plex86.org</A>
</DL></BLOCKQUOTE>
<BLOCKQUOTE>
[Heather] 
They might enjoy TuxRacer, which I've actually seen in stores.  Linux
can also emulate Nintendos, Game Boys, and some other gaming systems --
you have lots of options.
</BLOCKQUOTE>

<!-- 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">If You're Not Part of the Solution, You're Part of the Precipitate</FONT></H3>
Thu, 29 Aug 2002 16:54:14 -0700
<BR>Rick Moen (<a href="mailto:linux-questions-only@ssc.com?cc=dan@ssc.com&cc=rick@linuxmafia.com&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%238">the <em>LG</em> Answer Gang</a>)



<!-- ::
If You're Not Part of the Solution, You're Part of the Precipitate
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:: -->
<P>
Quoting Dan Wilder:
</P>
<P><STRONG><BLOCKQuote>
Another spate of Klez worm reports to the victim, whose email
address is forged in the "From: " header of the virus-bearing mail.
</BLOCKQuote></STRONG></P>
<P>
I've started letting people whose autoresponders send me these
misdirected advisories that they have one day to turn it off or disable
it, after which they'll be permanently killfiled after the next offence.
</P>
<P>
Dear readers:  If you don't know how to (or buy) an autoresponder that
does <EM>competent</EM> SMTP header analysis, so you're <EM>sure</EM> it's sending
virus advisories to the correct party, then you honestly have no
business running one, and will end up causing large numbers of people to
classify you as, in effect, a spammer and to act accordingly.
</P>
<P>
Trust me, you don't want to put yourself in that category -- and
nobody's going to care about your protestations of meaning well.
</P>

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<P> <A NAME="tips/9"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">autocad on linux</FONT></H3>
Sat, 31 Aug 2002 13:06:04 -0500
<BR>Richard Brown (<a href="mailto:linux-questions-only@ssc.com?cc=linux-questions-only@ssc.com&cc=rtbrown@sbcglobal.net&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%239">rtbrown from sbcglobal.net</a>)



<!-- sig -->


<!-- sig -->

<P>
Saw your not yet.  I am a mechanical engineer.   I run autocad daily on linux
using vmware.  (Running <A HREF="http://www.suse.com/">SuSE</A> 8.0 or 7.3, AMD 1.4 with 768 Mg) Works
beautifully.  Frequently I had 10 or 15 sessions of autocad running at the
same time.   Never a problem.  Nice also when want to reload or update as
from 7.3 to 8.0 simply copy the back the windows 2000 file.  To me it is the
preferrable way to run autocad.
</P>
<P>
-richard
</P>

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<P> <A NAME="tips/10"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">ringing a bell when compilation is finished</FONT></H3>
Tue, 24 Sep 2002 11:19:14 -0400
<BR>Allan Peda (<a href="mailto:linux-questions-only@ssc.com?cc=pedaa@rockefeller.edu&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%2310">pedaa from rockefeller.edu</a>)



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<!-- sig -->

<P>
Hi:
</P>
<P><BLOCKQuote>
I wanted to share a little bash function I put together to check for the
status code returned by a process (typically "make").
After using IDEs which generate audio feedback after successful
compilation, I realized that this could be done by a bash function,
which I call "ok".
</BLOCKQuote></P>
<P>
I typically run the function right after a long build like this:
</P>

<blockquote><code><font color="#000033"><br>make -f Makefile ; ok
</font></code></blockquote>
<P>
It then returns a pleasant note if all went well, and something less
pleasant if not.  Here is the source:
</P>

<blockquote><pre>[zorro@box84 build]$ cat /etc/profile.d/check_return_value.sh
#!/bin/sh

ok() {
    if [ $? -eq 0 ]; then
        play /usr/share/sounds/chord.au
        echo "   SUCCESS   "
    else
        play /usr/share/sounds/warning.wav
        echo "   *ERROR*   "
    fi
}
</pre></blockquote>
<P>
Works every time (so far).
</P>

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<P> <A NAME="tips/11"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Configuring the GUI, the GUI way</FONT></H3>
Sat, 24 Aug 2002 15:23:18 -0400
<BR>Benjamin A. Okopnik (<a href="mailto:linux-questions-only@ssc.com?cc=star@starshine.org&cc=ben@callahans.org&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%2311">ben from callahans.org</a>)
<BR>Question by Heather Stern (<a href="mailto:linux-questions-only@ssc.com?subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%2311">star@starshine.org</a>)

<!-- ::
Configuring the GUI, the GUI way
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
:: -->
<P>
Heather Stern wrote:
</P>
<P><BLOCKQuote>
(In response to q querent having trouble with mice)
</BLOCKQuote></P>
<P>
The section you are looking for in your <TT>/etc/X11/XF86Config-4</TT> file
(well, it might be in just plain <TT>/etc</TT>, but anyway) is "Pointer" for
the mice declarations themselves and "ServerLayout" for the list of
gadgets it will honor.
</P>
<BLOCKQUOTE>
[Ben] 
You could also use "<tt>xf86cfg</tt>" if you like graphical tools. I've found
that it takes a little getting used to, but is well done, and - once you
understand the basic idea behind the layout - nicely intuitive.
</BLOCKQUOTE>
<BLOCKQUOTE>
[Heather] 
Ben presumes you use <A HREF="http://www.debian.org/">Debian</A>.  If you use RedHat, you'd want
"<tt>Xconfigurator</tt>".  If you use <A HREF="http://www.suse.com/">SuSE</A>, the correct beastie is "<tt>SaX</tt>" and
can also be found in the YaST menus.
</BLOCKQUOTE>
<BLOCKQUOTE>
On older distros there was a TCL/tk app called "<tt>XF86Setup</tt>" but it does
nothing to help guess your video card or monitor characteristics.  If
you need this, a brief glance at the results of "<tt>lspci</tt>" is worth your
while, and check your notes about what the maximum resolution is for your
monitor, <EM>before</EM> you run the app.  It's not very happy when you switch
away from its task and back again.
</BLOCKQUOTE>
<BLOCKQUOTE>
The XF86Setup program, at least, has keyboard commands for everything,
so it will work that way until you finally pick the right mouse protocol
and can start clicking on things.
</BLOCKQUOTE>
<BLOCKQUOTE>
If you're afraid of jumping to graphical mode until you've got something
like a useful config file created, "<tt>xf86config</tt>" is a totally text mode
program, which asks you questions from the database of X gadgetry.
But do make sure that it creates an XFree86 version 4.x file, and not a
version 3.x file ... they are very different.  The section
"ServerLayout" mentioned above didn't exist in version 3.
</BLOCKQUOTE>

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<P> <A NAME="tips/12"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Diald problems again</FONT></H3>
Sun, 1 Sep 2002 09:08:59 +0100
<BR>Neil Youngman (<a href="mailto:linux-questions-only@ssc.com?cc=n.youngman@ntlworld.com&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%2312">n.youngman from ntlworld.com</a>)



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<P>
I've got <A HREF="http://www.debian.org/">Debian</A> 3.0 almost set up to my liking, but one thing I can't get to
work is diald.
</P>
<P>
I installed Debian from scratch and pppd configuration was quite easy. "pon
ntlworld" works, similarly kppp only required me to change auth to noauth in
ppp.options and it worked. Diald OTOH has me puzzled.
</P>
<P>
Debian 3.0 has a completely new diald configuration. All the stuff that used
to appear in <TT>/etc/diald</TT> has gone. The only configuration file it uses seems
to be in <TT>/var/cache.</TT>
</P>
<P>
"ps aux" shows that diald starts up OK.  "route" shows that it has set up sl0
as the default interface, but when I try to access anything on the internet I
get an immediate DNS lookup failure. There are none of the usual messages in
<TT>/var/log/messages</TT> indicating that it's trying to dial out and do a DNS lookup.
</P>
<P>
What have I tried?
</P>

<blockQuote><ul>
<LI>I've reconfigured it half a dozen times.

<LI>I've tried "grep diald /var/log/*"

<LI>I've copied my old /etc/diald from potato and selected "old-config" in
"dpkg-reconfigure diald".

<LI>I've copied the dialup rules from old standard.filters into /etc/diald.options

<LI>I've read everything I could find about the new configuration in
/usr/share/doc/diald

<LI>I've google searched for "debian woody diald problem"

<LI>I've searched the debian-user archives
</ul></blockQuote>
<P>
Now I'm stumped. I could throw away the new <TT>/etc/init.d/diald</TT> script and
import the old one potato, together with all the rest of the configuration
for potato, but even if that works, I would prefer not to rely on an
"obsolete" configuration.
</P>
<HR width="10%" align="center">
<blockquote><font color="#000066">But, about a week later, Neil solved it...
 -- Heather</font></blockquote>
<P>
I've got this working. It still doesn't work with the Debian 3.0
configuration, but I noticed that one difference from 2.2 was that there was
no named running on 3.0. I installed bind and this together with the 2.2
configuration seems to have got it working.
</P>
<P>
Neil
</P>

<blockquote><font color="#000066">I know that a few apps want to look up the local machine by hostname; I
usually deal with this by adding /etc/hosts entries.  But there are a
handful of other advantages to using a local caching name daemon.  If
you need the cache to persist through reboots (bad power lines, maybe?)
consider pdnsd.
 -- Heather</font></blockquote>

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<P> <A NAME="tips/13"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">dual boot with XP</FONT></H3>
Tue, 24 Sep 2002 01:45:27 -0700
<BR>Heather Stern (<a href="mailto:linux-questions-only@ssc.com?cc=debojitacharya@yahoo.com&cc=star@starshine.org&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%2313"><em>Linux Gazette</em> Technical Editor</a>)
<BR>Question by debojit acharya (<a href="mailto:linux-questions-only@ssc.com?subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%2313">debojitacharya@yahoo.com</a>)


<!-- sig -->


<!-- sig -->

<P><STRONG>
HalloMy name is Debojit Acharya and i am from india. It will be highly
apperciated if you kindly answer the questions furnished below :-1. I
have a 10 GB hard disk with Win 98 installed on it. Now i want to Install
Win XP and <A HREF="http://www.redhat.com/">Red Hat</A> Linux 7.2 on to a new 80 GB hard drive.
</STRONG></P>
<P>
I have seen this succeed;  it depends a little bit on whether your BIOS
likes such large drives, but once you can get the OS' to see them they
deal with the rest of the details pretty well.
</P>
<P><STRONG>
I want to have
multibooting feature with Win 98 (on the old 10GB HDD), Win XP and Linux
(on the new 80 GB HDD) as OSs.
</STRONG></P>
<P>
I don't know if mswin will let you boot XP from a second drive.
</P>
<P>
The easiest way by far for Linux, would be to have <TT>LOADLIN.EXE</TT> and a copy
of your favored linux kernel sitting on the old win98 C: ... then just
offer Linux as one of the mswin boot menu choices.
</P>
<P>
A floppy would work (for Linux at least;  possibly for winxp but don't
believe <EM>me</EM> ... check their knowledgebase).
</P>
<P><STRONG>
How to go about it? 2. I had Mandrake Linux 8.2 installed on one of
old HDD's partitions. Later i had tried to delete the partition by
booting from the Mandrake bootable CD. Though the partition got
deleted but had not been uninstalled properly because even now,
at the system startup screen, the default OS is shown as Linux with
Win 98 as the second choice. But after logging into Linux it gets
hanged.
</STRONG></P>
<P>
You still have the old LILO master boot record from the time when you
had Mandrake on <TT>/dev/hda</TT>, however since Mandrake itself ... or more
correctly speaking, that kernel ... is no longer there, the menu option
goes to an explicit location on disk -- which no longer has a kernel!
</P>
<P>
If you store at least one Linux kernel on your <TT>/dev/hda</TT> drive -- for
example, in C:\LINUX -- then you will be able to install a fresh LILO
boot record which points at it, and knows about you wanting to mount
a <TT>/dev/hdbN</TT> partition as your root volume when you select Linux.  You
must re-run <TT>/sbin/lilo</TT>, after editing <TT>/etc/lilo.conf</TT> to meet your
new setup.   Unfortunately, the kernel and bootloader really do have
to be on the same disk.
</P>
<P>
If you switch to GRUB a different story follows, but it's still probably
a good idea to keep a kernel on your first hard drive.
</P>
<P><STRONG>
Pls help me get out of this.
<br>Thanks. Bye,Debojit.
</STRONG></P>

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<P> <A NAME="tips/14"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Hiding SAMBA shares</FONT></H3>
Tue, 27 Aug 2002 12:59:52 -0700
<BR>CHADWICK (<a href="mailto:linux-questions-only@ssc.com?cc=chadwick@crosslink.net&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%2314">chadwick from crosslink.net</a>)



<!-- sig -->


<!-- sig -->

<P>
Take a look at this link it may help:
</P>
<P><BLOCKQuote>
<A HREF="http://www.oreilly.com/catalog/samba/chapter/ch05.html"
	>http://www.oreilly.com/catalog/samba/chapter/ch05.html</A>
</BLOCKQuote></P>
<P>
Look down the page to the section on Preventing Browsing (5.1.1)
</P>
<P>
O'Reilly's books are really great references for technical materials.
</P>
<P>
Hope this helps.
</P>

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<P> <A NAME="tips/15"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">recompiling the kernel with a X11 keymap</FONT></H3>
Sat, 21 Sep 2002 15:05:39 -0700
<BR>Dan Wilder (<a href="mailto:linux-questions-only@ssc.com?cc=&cc=dan@ssc.com&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%2315">dan from ssc.com</a>)
<BR>Question by hrdo (<a href="mailto:linux-questions-only@ssc.com?subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%2315"></a>)


<!-- sig -->

<P><STRONG>
Hello Answers Gang,
</STRONG></P>
<P><STRONG>
Is there a way to recompile the kernel so as to get
the X11 keymap in the console?
</STRONG></P>
<P>
See
</P>

<blockquote><code><font color="#000033"><br>linux/drivers/char/defkeymap.c
<br>linux/drivers/char/consolemap.c
</font></code></blockquote>
<P>
paying special attention to the comments at the beginning of
defkeymap.c
</P>
<P>
However, it is not necessary to recompile the kernel.  Your
initialization scripts (in <TT>/etc/rc.d</TT>, <TT>/etc/rc.d/init.d</TT>, or <TT>/etc/init.d</TT>
depending on your distribution) very likely have a call to "loadkeys"
someplace in them.  This loads a keymap at boot time.  If not, you can
easily add such.  See
</P>

<blockquote><code><font color="#000033"><br>man loadkeys
</font></code></blockquote>

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<P> <A NAME="tips/16"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Linux multilanguage</FONT></H3>
Tue, 3 Sep 2002 12:27:00 -0500
<BR>Dan Wilder, Ben Okopnik (<a href="mailto:linux-questions-only@ssc.com?cc=Jeffrey_Kwiatkowski@baylor.edu&cc=linux-questions-only@ssc.com&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%2316">tag from ssc.com</a>)
<BR>Question by Jeff Kwiatkowski (<a href="mailto:linux-questions-only@ssc.com?subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%2316">Jeffrey_Kwiatkowski@baylor.edu</a>)


<!-- sig -->


<!-- sig -->

<P><STRONG>
Hey Jim,
</STRONG></P>
<P><STRONG>
I was reading over some of your responses to people's problems and
it seems you are pretty knowledgable of the linux os.
</STRONG></P>
<BLOCKQUOTE>
[Ben] 
These days, Jim sits by the fire in his slippers and points with his
pipe to stuff he wants done... or something like that. 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle"> The Answer Guy
is now The Answer Gang, and we all share the load.
</BLOCKQUOTE>

<blockquote><font color="#000066">With quite a shell collection on the mantelpiece, I'd add.  (Jim is our
resident shell-script expert.  He has no problem constructing shell
pipelines several apps deep.)
 -- Heather</font></blockquote>
<BLOCKQUOTE>
I was wondering
if you could point me in the correct direction with an issue i am
facing.  I am looking to write a C program that will use some sort of
API call to detect what language is installed on a linux box and then
launch a correct web page.  Does linux have an API?  How do you find out
these environment variables?  I have been researching for hours and have
come up empty.  Any help would be very appreciated.
</BLOCKQUOTE>
<BLOCKQUOTE>
[Dan] 
No doubt Jim or somebody else has more info, but for starters,
try
</BLOCKQUOTE>

<blockquote><code><font color="#000033"><br>  apropos locale
</font></code></blockquote>
<BLOCKQUOTE>
and the related manpages, for example
</BLOCKQUOTE>

<blockquote><code><font color="#000033"><br>  man 7 locale
</font></code></blockquote>
<BLOCKQUOTE>
A system's locale is set during installation, and controls
among other things the multilanguage support built into many
GNU programs using the "gettext" utilities.  See also
</BLOCKQUOTE>

<blockquote><code><font color="#000033"><br>  man gettext
</font></code></blockquote>
<BLOCKQUOTE>
[Ben] 
Take a look at the LANG variable. It's somewhat odd (e.g., the default
value for English is 'C' (???))
</BLOCKQUOTE>
<BLOCKQUOTE>
[Heather] 
I think the default <EM>value</EM> is 'C' and if you have a basically English
distro that's the language you'll, ahem, C.  You can specify one or
another of the English variants but I've seen it cause some things to
act weird - I assume the exact same weirdness they'd offer if I picked
an international variant they dunno how to handle.
</BLOCKQUOTE>
<BLOCKQUOTE>
[Ben] 
...but mostly it follows the ISO3166
standard for naming, e.g. "de", "fr", "kr", etc. It's also far from
certain that everyone will have it set on their system. For example, I
read a lot of Russian stuff, but leave my LANG at the default setting
and execute specific programs with a local LANG definition:
</BLOCKQUOTE>

<blockquote><pre>LANG=ru_RU rxvt -n Muttley -e mutt -y
</pre></blockquote>
<BLOCKQUOTE>
In my opinion, though, LANG is as close as you'll come to what you're
looking for as is possible in the wild wooly world of Unix.
</BLOCKQUOTE>

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<P> <A NAME="tips/17"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">Re: exe to iso files</FONT></H3>
Tue, 27 Aug 2002 00:17:37 -0700
<BR>Jim Dennis (<a href="mailto:linux-questions-only@ssc.com?cc=jra@baylink.com&cc=jimd@starshine.org&subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%2317">the <em>LG</em> Answer Guy</a>)
<BR>Question by Jay R. Ashworth (<a href="mailto:linux-questions-only@ssc.com?subject=%20Re%3A%20%5BLG%2083%5D%202c%20Tips%20%2317">jra@baylink.com</a>)


<!-- sig -->


<!-- sig -->


<blockquote><font color="#000066">And if you're trying to write a Linux or otherwise generated ISO under
Windows, you can see "Best of ISO Burning Under Windows" - Issue 68,
11th TAG article:
 	<A HREF="../issue68/tag/11.html"
	>http://www.linuxgazette.com/issue68/tag/11.html</A>
 -- Heather</font></blockquote>
<P><STRONG>
Interestingly enough, I discovered, apparently El Torito bootability is
a feature of the image -- I burned those Linux BBC's from a bare ISO,
no command switches to tell the Windows burner to make it bootable, and
it Just Worked.
</STRONG></P>
<P><STRONG>
I hadn't realized that it was (in Linux terms) mkisofs, not cdrecord,
that did that work.
</STRONG></P>
<BLOCKQUOTE>
[JimD] 
Yes, it's the -b option to mkisofs that does the trick (and it's obviously
not necessary at record time --- though most other OS have software that
integrate the mkisofs with the burn.  I prefer the modularity of he Linux
approach.
</BLOCKQUOTE>
<P><STRONG>
In retrospect it ought to be obvious, but I don't even want to admit to
the amount of time I spent looking for that switch in my (by which I
mean "my sister's") Windows burner software.
</STRONG></P>

<!-- end 17 -->
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<P> <A NAME="tips/lj"><HR WIDTH="75%" ALIGN="center"></A> <P>
<H3><IMG ALIGN=BOTTOM ALT="" SRC="../gx/lil2cent.gif">
<FONT COLOR="navy">LJWNN Tech Tips</FONT></H3>
Mon, 30 Sep 2002 11:22:02 -0700


<h4 align="center"><br>Keeping NAT connections alive
</h4>
<P>
When you ssh from a NAT network, do your connections mysteriously drop
after a few minutes of activity?
</P>
<P>
Keep ssh connections up by adding
</P>
<P>
ProtocolKeepAlives 30
</P>
<P>
to your ~/.ssh/config file.
</P>
<P>
See man ssh_config.
</P>

<!-- end 18 -->
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
<h5>This page edited and maintained by the Editors of <I>Linux Gazette</I><br>HTML script maintained by <A HREF="mailto:star@starshine.org">Heather Stern</a> of Starshine Technical Services, <A HREF="http://www.starshine.org/">http://www.starshine.org/</A>
<br>Copyright &copy; 2002
<br>Copying license <A HREF="http://www.linuxgazette.com/copying.html">http://www.linuxgazette.com/copying.html</A>
<BR>Published in Issue 83 of <i>Linux Gazette</i>, October 2002</H5>
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
<HR>

<TABLE width="100%" BORDER><TR><TD WIDTH="200">
<A HREF="http://www.linuxgazette.com/">
<IMG ALT="LINUX GAZETTE" SRC="../gx/2002/lglogo_200x41.png" 
	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 -->


<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/qbub.gif" height="28" width="50"
	  alt="(?)" border="0"
	><strong>Issue 80 - The Mailbag -> Kylix - observations</strong></a>
<dt><A HREF="#tag/2"
	><img src="../gx/dennis/qbub.gif" height="28" width="50"
	  alt="(?)" border="0"
	><strong>starting services in "/etc/init.d"</strong></a>
<dt><A HREF="#tag/3"
	><img src="../gx/dennis/qbub.gif" height="28" width="50"
	  alt="(?)" border="0"
	><strong>A LAN Question</strong></a>
<dt><A HREF="#tag/4"
	><img src="../gx/dennis/qbub.gif" height="28" width="50"
	  alt="(?)" border="0"
	><strong>Homework question: defining subnets</strong></a>
<dt><A HREF="#tag/5"
	><img src="../gx/dennis/qbub.gif" height="28" width="50"
	  alt="(?)" border="0"
	><strong>thx for ur ncurses, u have networking howto?</strong></a>
<dt><A HREF="#tag/6"
	><img src="../gx/dennis/qbub.gif" height="28" width="50"
	  alt="(?)" border="0"
	><strong>How to kill a process in uninterruptible sleep state?</strong></a>
<!-- index_text ends -->
</DL>
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<A NAME="tag/greeting"><HR WIDTH="75%" ALIGN="center"></A>
<H3 align="left"><img src="../gx/dennis/hbubble.gif" 
	height="50" width="60" alt="(&para;) " border="0"
	>Greetings from Heather Stern</H3>
<!-- begin hgreeting -->
<blockQuote>
Dear readers, welcome to October in the world of The Answer Gang.
</blockQuote>
<blockQuote>
Statistics: About 680 messages this month.  I say "about" because I can't count spam
that hit the filters, and I'm not counting admin notes that I spotted and put aside
early.  That's just the total I had to split.
</blockQuote>
<blockQuote>
Peeves of the month --or-- how <EM>not</EM> to get an answer:
</blockQuote>

<blockQuote><ol>
<LI>ask a question about printers, and don't bother to look at <A HREF="http://www.linuxprinting.org"
	>http://www.linuxprinting.org</A> first.

A lot of our answers are gentle pointers to HOWTOs, as we assume real newbies
don't know about The Linux Documentation Project (<A HREF="http://www.tldp.org"
	>http://www.tldp.org</A>) yet, either.

<br>&nbsp;
<br>If you <EM>have</EM> already looked at a a HOWTO, for a pumpkin's sake do <EM>not</EM> say
"I looked at all the HOWTOs and it made no sense."  That just makes us sad and worried
that our own answers won't help you any either.  
<br>&nbsp;
<br>Tell us whatever phrases confused
you, and tell us what sort of sense you expected of it.   We may be inspired to "translate"
the techie bits into English, or point you at the pre-requisite HOWTO that goes before
it, which already does.  Probably we'd copy the maintainer so that the clearer answer
gets to help a lot more people.    If so you could feel proud you'd helped the LDP by
making it more readable 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle">


<LI>gosh, it's my first week of school, maybe those Answer Guys will do my homework
for me.  I dunno what the prof is talking about anyway, so I won't even rephrase
he question.
<br>&nbsp;
<br>"sure, give us your professor, we'll advise him on a few pointers to give you."  Here's
the first hint;  try the class textbook.  The second: if you don't understand the
question ask the professor about it.  It's his or her job to explain it to you;  you
pay the school good money for that.
<br>&nbsp;
<br>Especially distressing were the ones who want us to pick their masters thesis for them.
Research and new insights are the basis for handing out such a degree, right?  So I'd
think it needs a bit more research than firing a note off to a batch of linux gurus
on some mailing list somewhere.  You need some background, you need a topic, you need
some actually interesting new theory, you need some ways to test or explore that theory,
and then you need to make the paper presentable at an academic level.  I suggest typing
the keywords "linux" and "proceedings" into the nearest search engine, and following their
examples for style, reading them for content, and considering whether they are aiming
for the same academic audience or if you need a slightly different tone.  Simmer with
new ideas, garnish lightly with a conclusion, publish to taste. Keep notes throughout
and have a complete bibliography so people can follow how you came to think of it all.
</ol></blockQuote>
<blockQuote>
Not really a peeve at all, but rather interesting: Crossover questions with Microsoft OS'
are up.  On the other tentacle, awareness that they're talking to Linux people here is too.
For the record two Knowledgebases might come in handy:
</blockQuote>

<blockQuote><ul>
<!-- *) ours -- http://www.linuxgazette.com/tag/kb.html -->

<LI>ours -- <A HREF="../tag/kb.html"
	>http://www.linuxgazette.com/tag/kb.html</A>

<!-- *) theirs -- http://support.microsoft.com/ -->

<LI>theirs -- <A HREF="http://support.microsoft.com"
	>http://support.microsoft.com</A>
</ul></blockQuote>
<blockQuote>
No, we have no idea whether any MS varieties can boot off a second drive.  We suggest
swapping the disks.  Linux will boot fine as long as the bootloader has a kernel on
the same media.  Even if that's a floppy with SYSLINUX, or a Windows install with
<TT>LOADLIN.EXE</TT> lying around.
</blockQuote>
<blockQuote>
Here's a touch of what The Answer Guy himself (Jim Dennis) and I have been up to.  We
visited Portland, Oregon this weekend - meeting some old friends - and got a tip about
this great recycling project, <A HREF="http://www.FreeGeek.Com"
	>http://www.FreeGeek.Com</A>.  We swung by their offices and
it's just the coolest thing...  assuming that you find big boxes piles of discarded cards
and monitors and so on fascinating, of course.  We sure did 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle">  
</blockquote>		
		
<blockquote>Anyways, they get people
in the community involved in putting these old bits back together into wimpy little
machines that Linux can still make usable.  The stuff that's hopeless, they snip the
heavy metals and chips out of for recycling.  Meanwhile some folks who previously knew
nothing about computers, except maybe "where's the on switch" are learning how to tell
an ethernet card from a modem, and so on.  There are probably other projects like this
out there, too.  I'd like to hear from a few of them.
</blockQuote>
<blockQuote>
Now on to some All Hallow's Eve fun.
</blockQuote>
<blockQuote>
We really had to start coughing while cleaning out the cobwebs this time.  Not one, but <EM>two</EM>
questions about copies of <A HREF="http://www.redhat.com/">Red Hat</A> so old the moths are stuffed and buzzing around with beards
and canes.  The answers weren't very tasty, so you'll be spared them.
</blockQuote>
<blockQuote>
For slimy worms we've been pestered by the Klez worm all month.  See the Two Cent Tips for
more on <EM>that</EM>.  Ugh.
</blockQuote>
<blockQuote>
We do have some candy though.
</blockQuote>
<blockQuote>
Ghoulies and monsters, we've got a definition of the term daemon that might
be particularly useful this month.  Plus how to get 'em started.   LAN stuff
got you spooked?  We've got some great notes to chew on.  if you find
uninterruptiple sleep bothers you, we'll tell you how to kill that ghost...
probably!  Mwa ha ha ha, ha ha!  See you next month!
</blockQuote>

<!-- end hgreeting -->
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<A NAME="tag/1"><HR WIDTH="75%" ALIGN="center"></A>
<!-- begin 1 -->
<H3 align="left"><img src="../gx/dennis/qbubble.gif" 
	height="50" width="60" alt="(?) " border="0"
	>Issue 80 - The Mailbag -> Kylix - observations</H3>


<p><strong>Translation (c) 2002 Santy 
</strong></p> 

<p align="right"><strong>Answered By  Faber Fedor, Ben Okopnik, John Karns, Mike Orr, Heather Stern
</strong></p>
<blockQuote>
Hello!, I suppose that somebody already will have clarified this to you,
but just in case...
</blockQuote>
<blockQuote>
(I am Spanish, and my English is not very good, I hope that it is
sufficient to explain to me well...)
</blockQuote>

<blockquote><code><font color="#000033"><br>Kylix
<br>Fri, 21 Jun 2002 14:37:51 -0400
<br>Octavio Aguilar (oam from mail.cosett.com.bo)
<br>translated by Mike Orr, except for one part by Heather Stern.
</font></code></blockquote>
<P><STRONG><IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	>
!ah! Un comentario demonio (daemon )siguifica Dinamic access memory, estoy
equivocado?
</P>
<P>
Ah! A daemon commentary means dynamic access memory, or am I mistaken?
</STRONG></P>
<P><STRONG>
Octavio-- Sorry, I've never used Kylix. I just ran a demo once. I don't understand your
second question. Memory is hardware; a daemon is software. And what's a "daemon
commentary"?
</STRONG></P>
<blockQuote><IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Santy]
Here Octavio asks if daemon (demon is "demonio" in spanish) means "dynamic access
memory" I believe that he thinks that daemon is an acronym -&gt;"D-ynamic A-ccess
EM-memory ON-???) or so, of course this mistaken, it cames from Day Monitor
&iquest;yes?.
</blockQuote>
<blockQuote>
I believe that this clarifies your doubt, I hope...
</blockQuote>
<P><STRONG><IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	>
Intente bajar de internet el mismo paquete pero el resultado para instalarlo es el
mismo error.
(Heather: oboy, my spanish is rustier than Mike's, but I'll try.)
I intend to go under the internet to packets (maybe: download the package ?) but the
result of installing is an error.
</STRONG></P>
<blockQuote><IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Santy]
I intend to download the package from internet but the result of installing is the same
error.
</blockQuote>
<blockQuote>
Bye!
</blockQuote>
<HR width="10%" align="left"><P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
Santy writes:
</STRONG></P>
<P><STRONG><BLOCKQuote>
of course this mistaken, it cames from Day Monitor &iquest;yes?.
</BLOCKQuote></STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Faber] 
I've heard that daemon stands for Disk And Execution MONitor.  Whether
that's true or not is, I suspect, lost in the mists of history.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Ben] 
In The Jargon File:
</blockQuote>
<blockQuote><BLOCKQuote>
:daemon: <TT>/day</TT>'mn/ or <TT>/dee</TT>'mn/ <TT>/n./</TT>  [from the mythological
</BLOCKQuote></blockQuote>
<blockQuote>
meaning, later rationalized as the acronym `Disk And Execution
MONitor'] A program that is not invoked explicitly, but lies
dormant waiting for some condition(s) to occur.
....
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [John K.] 
According to my first edition copy of "UNIX System Administration
Handbook", Nemeth, Synder &amp; Seebass, pp 403-404,
</blockQuote>
<blockQuote>
"Many people equate the word 'daemon' with the word 'demon' implying some
kind of Satanic connection between UNIX and the underworld.  This is an
egregious misunderstanding.  'Daemon' is actually a much older form of
'demon'; daemons have no particular bias towards good or evil, but rather
serve to help define a person's character or personality.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Mike Orr] 
Similar to the Russian word "chyort", which means "earth spirit", but
Christian theology and writers (e.g., Tolstoy) tended to redefine as "devil".
</blockQuote>
<blockQuote>
There's an anecdote about a priest who's conducting a funeral service.
As the casket is about to be buried, an earthquake erupts, pushing the casket
into the earth.  "Chyort voz'mi!" ("The devil take it!") mutters the priest and
continues the service, not realizing the literal meaning of that common expression.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [John K.] 
The ancient
Greeks' concept of a "personal daemon" was similar to the modern concept
of a "guardian angel" -- "eudaemonia" is the state of being helped or
protected by a kindly spirit.  As a rule, UNIX systems seem to be infested
with both daemons and demons.  [ :-^) as it were, hehe! - jk]
</blockQuote>
<blockQuote>
The word daemon was first used as a computer term by Mick Bailey, a
British gentleman who was working on the CTSS programming staff at MIT
during the early 1960's.  (footnoted: This bit of history comes from Jerry
Saltzer at MIT, via Dennis Ritchie, via Kirk McKusick.)  Mick quoted the
Oxford Dictionary in support of both the meaning and spelling of the word.
Daemons made their way from CTSS to Multics to UNIX, where they are so
popular they need a superdaemon to manage them.  Daemons are featured on
the cover of the BSD UNIX manuals.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Heather] 
I've been told that the little trident in the BSD Daemon's hands is not
a weapon, simply his implementation of the <TT> fork()</TT> system call... but I
couldn't find a canonical reference to say so.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [John K.] 
... cyber-history class dismissed 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle">
</blockQuote>
<blockQuote>
These figures [defining the personality] also appear prominently in
Tibeten (and Hindu if I'm not
mistaken) drawings called mandalas.  Many of the mandalas have these
figures painted in a circular or horse shoe pattern surrounding a central
figure.  At the moment I forget the term that <EM>they</EM> use to name the
entities, but they are representative of universal characteristics of the
subconscious, which every person who follows "the path" must master /
transcend.
</blockQuote>

<!-- end 1 -->
<!--     .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.     -->
<A NAME="tag/2"><HR WIDTH="75%" ALIGN="center"></A>
<!-- begin 2 -->
<H3 align="left"><img src="../gx/dennis/qbubble.gif" 
	height="50" width="60" alt="(?) " border="0"
	>starting services in "/etc/init.d"</H3>


<p><strong>From Benjamin A. Okopnik 
</strong></p> 

<p align="right"><strong>Answered By  Jay R. Ashworth, Mike "Iron" Orr, John Karns, Jim Dennis
</strong></p>
<P><STRONG>
There are a number of services available in "<TT>/etc/init.d</TT>" that I use
only occasionally - "pdnsd" and "ntpdate", for example - and so they're
not auto-started in my "<TT>/etc/rc*.d</TT>". In order to save myself repeatedly
typing
</STRONG></P>

<blockquote><code><font color="#000033"><br>su -c '/etc/init.d/pdnsd start'
</font></code></blockquote>
<P><STRONG>
"stop", etc., I decided to make the command line a bit clearer via the
following script:
</STRONG></P>
<p align="center">See attached <tt><a href="misc/tag/okopnik.usr-local-bin-start.bash.txt">okopnik.usr-local-bin-start.bash.txt</a></tt></p>
<P><STRONG>
After creating it, I made a number of symlinks to it:
</STRONG></P>

<pre><strong>cd /usr/local/bin
for n in stop reload restart force-reload; do ln -s start $n; done
</strong></pre>
<P><STRONG>
Now, all I have to do is type an action followed by the service name,
like
</STRONG></P>

<pre><strong>reload pdnsd
start fetchmail
stop mysql
</strong></pre>
<P><STRONG>
etc., as root (or invoke it via "su"). More obvious, less typing.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [jra] 
Except that they're a bit too generic in the global unix namespace,
IMHO.  I did something similar, with a script called svc, about a
release or two before RedHat did something almost identical (though a
bit spiffier) called service.
</blockQuote>
<P>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
&lt;shrug&gt; It's easy enough to modify for other "rc.d" variants. The
important thing here was the idea, and the, erm, "source" is available.

<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle">
</P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Iron] 
For a simpler (and more simplistic way), you can throw these shell functions
into .zshrc.
</blockQuote>

<blockquote><pre>function start () { /etc/init.d/$1 start ; }
function stop () { /etc/init.d/$1 stop ; }
function reload () { /etc/init.d/$1 reload ; }
function restart () { /etc/init.d/$1 restart ; }
function ctest () { /etc/init.d/$1 ctest ; }
</pre></blockquote>
<blockQuote>
Also easier to type than 'service start'....
</blockQuote>
<blockQuote>
(I assume bash works the same way?)
</blockQuote>
<P>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
You need to have semicolons on the ends...
</P>

<blockquote><em><font color="#000066">which I added.
 -- Heather</font></em></blockquote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Iron] 
That may be a bashism; it works in zsh without the semicolon.  And why would
you need a semicolon?  You normally only need a semicolon between statements,
in "for WORDS ;do", and in the case statement.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [JimD] 
Actually this was fixed in bash 2.x.  The fact that bash 1.x allowed
{ WORDS } (with no semicolon) is considered a bug in its parser.  That's
because } is NOT a command separator --- and the command echo } should
simply echo a closing brace.  That leads to an ambiguity in the following:
</blockQuote>
<blockQuote><BLOCKQuote>
{ echo }
</BLOCKQuote></blockQuote>
<blockQuote>
... is that a complete command group (in the braces) or is it a fragment
including the beginning of a command group (the opening brace) followed
by an echo command (which will print out a close brace character, and a
newline)?
</blockQuote>
<blockQuote>
Alternatively the command line:
</blockQuote>
<blockQuote><BLOCKQuote>
{ echo ; }
</BLOCKQuote></blockQuote>
<blockQuote>
... is unambiguous.
</blockQuote>
<P>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
It's an "sh"-ism, too.  You need one because it terminates a group command. From the "bash" man page:
</P>

<pre> { list; }
        list  is  simply  executed  in  the current shell environment.
        list must be terminated with a newline or semicolon.  This  is
        known  as a group command.
</pre>
<P>
It doesn't work in .bashrc. Remember that you have to "su" to run them:
</P>

<pre>Baldur:~$ ztart() { /etc/init.d/$1 start; }
Baldur:~$ su -c 'ztart pdnsd'
Password:
bash: ztart: command not found
Baldur:~$ typeset +f | grep -A3 ztart
ztart ()
{
    /etc/init.d/$1 start
}
</pre>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Iron] 
I rarely use the "su -c" syntax.  By the time you get done typing the convoluted
syntax with quotes around the command, you can already be done with an
interactive su session.
</blockQuote>
<P>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
The point here is that doing it the way you suggest makes it more
complex (dependent on whether you did "su" or "su -", for example) and
more fragile. I suppose you could always put it in "<TT>/etc/profile</TT>"...
uh, nope, that would break for "csh", "tcsh", etc. users.  This is one
of those cases where a script is simply better.
</P>
<P>
No idea what you mean by "convoluted syntax", but the same reasoning
applies.
</P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [JimD] 
In the case of zsh it appears to treat the close brace as a special
case delimiter.  This leads to inconsistencies like this:
</blockQuote>

<blockquote><pre>  zsh$ echo {}
  {}
  zsh$ echo {
  {
  zsh$ echo }
  zsh: parse error near `}'
</pre></blockquote>
<blockQuote>
(or something like that).  This is probably a bug in zsh (with regards
to Bourne and Korn shell compatibility.  As I say, it was considered to
be a bug in bash that was noted in a change log for 2.x.
</blockQuote>
<blockQuote>
All of that hairsplitting aside I must say that this is one of the most
annoying changes in bash 2.x.  Like many other shell scripters I'd gotten
into the habit of using constructs like { ...; foo } and I still get
bitten by it occasionally.  (Note that in this example foo is being called
with an argument of } (closing brace) and the group is incomplete.
We must insert a semicolon or a newline (command separators) for it to
parse correctly.
</blockQuote>
<P>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
I'd simply learned it as "this is the way it's done"; I guess I came to
it fairly late. One thing that I remember annoyed the hell out of me
early on: trying to launch two progs and background the first one;
seemed like an obvious thing to do
</P>
<P>
prog1 &amp;; prog2
</P>
<P>
- right? Wrong! Only later did I realize that '&amp;' was a valid
</P>
<P>
terminator, just like ';' and newline. Oh, and trying to explain the
order in
</P>
<P>
prog &gt; <TT>/dev/log</TT> 2&gt;&amp;1 &amp;
</P>
<P>
to my students involves removing their brains and installing them upside
down...
</P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [JimD] 
Consistency is the hobgoblin of a small mind.  Computers have "small
minds" indeed!
</blockQuote>
<P>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
&lt;snort&gt; Indeed.
</P>
<HR width="10%" align="left"><blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [John K.] 
Interesting, as I did virtually the same thing a while back:
</blockQuote>
<p align="center">See attached <tt><a href="misc/tag/karns.usr-local-sbin-start.sh.txt">karns.usr-local-sbin-start.sh.txt</a></tt></p>
<blockQuote>
but I put it all in <TT>/usr/local/sbin</TT>, since it has to run as root
</blockQuote>

<blockquote><pre>lrwxrwxrwx    1 root     root            9 Dec  7  2001
/usr/local/sbin/start -&gt; initScrpt*
</pre></blockquote>

<TABLE WIDTH="95%" BORDER="1" BGCOLOR="#FFFFCC"><TR><TD>
<p align="center">...............</p>

<blockquote><code><font color="#000033"><br># echo "command = /etc/init.d/$1 $0"
<br>CMD=`echo $0 | cut -f5 -d/`
</font></code></blockquote>
<p align="center">...............</p>
</TD></TR></TABLE>
<blockquote><em><font color="#000066">This should chop off 5 fields worth of text, delimited by slashes.
Any time you see fixed numbers while doing string handling, you
should beware that it won't work for the general case.
-- JimD
</font></em></blockquote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
Yikes! Highly breakable (try invoking it from its own directory, one
level above it, etc.) How about just "${0##*/}" instead? That'll work
every time.
</STRONG></P>

<blockquote><em><font color="#000066">This offers to chop everything up to the last slash, and leave the
last part, whatever it is.  Also it's a built-in.   But that may be
true only for bash... and probably ksh.  The rest is left as an exercise
in shell debugging, but those of you who prefer working code should just
skip to the end.
-- JimD
</font></em></blockquote>

<TABLE WIDTH="95%" BORDER="1" BGCOLOR="#FFFFCC"><TR><TD>
<p align="center">...............</p>

<blockquote><code><font color="#000033"><br>if [ $0 = 'stop' ] ; then
</font></code></blockquote>
<p align="center">...............</p>
</TD></TR></TABLE><P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
Has this ever worked for you? I'd be very surprised if so; $0 will never
equal just "stop" (it'll be "<TT>./stop</TT>" at the very least.)
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [John K.] 
Yes.
</blockQuote>

<blockquote><pre>jkInsp8000:~ # stop nscd
Shutting down Name Service Cache Daemon
</pre></blockquote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
Doesn't work for me. Obviously, something in your script is tripping off
"stop", but I see no way that it can be the above "if" statement.
</STRONG></P>
<p align="center">See attached <tt><a href="misc/tag/okopnik.testing-karns.sh-transcript.txt">okopnik.testing-karns.sh-transcript.txt</a></tt></p>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [John K.] 
As a test I truncated the script as:
</blockQuote>

<blockquote><pre>CMD=`echo $0 | cut -f5 -d/`
echo "CMD = $CMD"
exit 0
</pre></blockquote>
<blockQuote>
... then ran the tests
</blockQuote>
<blockQuote>
..from root's home dir:
</blockQuote>

<blockquote><pre>jkInsp8000:~ # stop nscd
CMD = stop
</pre></blockquote>
<blockQuote>
..from the scripts own dir:
</blockQuote>

<blockquote><pre>jkInsp8000:~ # cd /usr/local/sbin/
jkInsp8000:/usr/local/sbin # stop nscd
CMD = stop
</pre></blockquote>
<blockQuote>
..and from one level above:
</blockQuote>

<blockquote><pre>jkInsp8000:/usr/local # stop nscd
CMD = stop
</pre></blockquote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
Mine acts completely differently 
<IMG SRC="../gx/dennis/unsmily.gif" ALT=":(" 
		height="24" width="20" align="middle">
</STRONG></P>

<pre><strong>Baldur:~$ cat &lt;&lt; ! &gt; /usr/local/bin/tst1
&gt; CMD=`echo $0 | cut -f5 -d/`
&gt; echo "CMD = $CMD"
&gt; exit 0
&gt; Baldur:~$ chmod +x /usr/local/bin/tst1
Baldur:~$ tst1
CMD =
Baldur:~$ cd /usr/local/bin
Baldur:/usr/local/bin$ tst1
CMD =
</strong></pre>
<P><STRONG>
Doesn't work for me, John. I can't see how it would work for you.  If
one of the other Gangsters wants to try it out, cool, but I don't see
how it's even possible (unless you have another script, alias, or
function called "stop".) Here is a simple test:
</STRONG></P>

<pre><strong>echo "./foo" | cut -f5 -d/
</strong></pre>
<P><STRONG>
If you get "foo" out of that, then your "cut" is doing something
magical. Or maybe it's "echo". Of course it could always be gremlins.
</STRONG></P>
<P><STRONG>
Just out of curiosity - you <EM>are</EM> copying and pasting (NOT retyping) the
code, yes?
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [John K.] 
I'm too lazy to <EM>type</EM> it!  
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle">  At this point I'm tempted to say that I
personally modified the bash code to suite my misguided purpose (ah, the
joy of open source), but I didn't.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
I didn't think you had, but I was wondering about your gremlins. You
just never know.
</STRONG></P>

<pre><strong>jkarns@jkInsp8000:~ &gt; grep gremlin /etc/passwd
gremlin:x:0:666:i_gotz_r00t:/proc/bus/pci/...:/bin/bash
</strong></pre>
<P><STRONG>
<IMG SRC="../gx/dennis/smily.gif" ALT="&lt;grin&gt;" 
		height="24" width="20" align="middle">
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [John K.] 
That's the only script - as I said I modified it for the test, and it
responded according to my mod, so it's the one being called.  Bash version
is:
</blockQuote>

<blockquote><pre>GNU bash, version 2.04.0(1)-release (i386-suse-linux)
Copyright 1999 Free Software Foundation, Inc.
</pre></blockquote>
<blockQuote>
Running your test:
</blockQuote>

<blockquote><pre>jkarns@jkInsp8000:~ &gt; echo "./foo" | cut -f5 -d/

jkarns@jkInsp8000:~ &gt;
</pre></blockquote>
<P>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
OK, in that case, here's a guaranteed way to break it:
</P>

<pre>cd /wherever/the/script/is
./stop
</pre>
<P>
I can promise you that it's going to fail. 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle"> Same story if you ever
move it into a directory that's "deeper" or "shallower" than the current
one (*there's* a hell of a problem to troubleshoot!) If you use
"${0##*/}", or even "echo $0|sed 's#.*/##'", that fragility goes away.
</P>

<blockquote><em><font color="#000066">Or get <EM>really</EM> lazy and just use "basename" which is designed for this.
-- JimD
</font></em></blockquote>
<p align="center">See attached <tt><a href="misc/tag/debugged.usr-local-sbin-start.sh.txt">debugged.usr-local-sbin-start.sh.txt</a></tt></p>

<!-- end 2 -->
<!--     .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.     -->
<A NAME="tag/3"><HR WIDTH="75%" ALIGN="center"></A>
<!-- begin 3 -->
<H3 align="left"><img src="../gx/dennis/qbubble.gif" 
	height="50" width="60" alt="(?) " border="0"
	>A LAN Question</H3>


<p><strong>From santyx 
</strong></p> 


<p align="right"><strong>Answered By  Ben Okopnik, Karl-Heinz Herrman, John Karns, Jim Dennis, Matthias Posseldt
</strong></p>
<P><STRONG>
Hello Gang!!!
Thanks and congratulations for your good work!!!
</STRONG></P>
<P><STRONG>
I'm Santiago (santyx), from San Rafael-Mendoza-Argentina.
I don't speak English very well, but I hope you understand my question.
I'm working in a LAN in my University and I've installed a <A HREF="http://www.redhat.com/">Red Hat</A> Linux 7.1
in my work station (puesto17).
The LAN looks like this:
</STRONG></P>
<p align="center">See attached <tt><a href="misc/tag/map-university-network.txt">map-university-network.txt</a></tt></p>
<P><STRONG>
Where SANRAFAEL is a WINDOWS NT server for the 192.168.2.X subnet and CHARLY
</STRONG></P>
<P><STRONG>
is a <A HREF="http://www.suse.com/">SuSE</A> LINUX server for the 192.168.1.X subnet.
SANRAFAEL is connected to the Internet, and allowing all the work stations
in
the network to connect to the Internet too, with a proxy software.
As you see, I don't have a direct connection to the Internet from puesto17.
I can do "ping" to 192.168.1.X or 192.168.2.X, but I can't do "ping", for
example, to <A HREF="http://www.argentina.com"
	>http://www.argentina.com</A> if I want.
I can do "traceroute" to 192.168.1.X or 192.168.2.X, but I can't do
"traceroute", for example, to <A HREF="http://www.hotmail.com"
	>http://www.hotmail.com</A> if I want.
I can do "ftp" to 192.168.1.X or 192.168.2.X, but I can't do "ftp", for
example, to my ISP to upload web pages if I want.
I can't connect to the News Servers in the Internet and I can't use my pop3
mail server from my work station.
I can't go out of my network!!!
</STRONG></P>
<P><STRONG>
Which is the best way to change this?
Can I change this from my Linux box?
Or the only way is changing the things in the SANRAFAEL Server?
</STRONG></P>
<P><STRONG>
I really need a solution, specially for the FTP, since I'm working in a web
site for my University.
</STRONG></P>
<P><STRONG>
Thanks in advance!!!.
Santyx.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Ben] 
Hi, Santyx -
</blockQuote>
<blockQuote>
It sounds like SANRAFAEL is running a firewall that's blocking (at
least) ports 7 (echo), 21 (ftp), 110 (pop), and 119 (nntp). Your system
administrator would have to open those for you.
</blockQuote>
<blockQuote>
Another possibility, depending on how your proxy is set up, is that you
might also be able to get out through that proxy. To do that, you'd have to
define some environment variables:
</blockQuote>

<blockquote><pre># Most programs want this in lowercase, but there are some that want it
# capitalized!
export http_proxy=http://x.x.x.x:y
export HTTP_PROXY=http://x.x.x.x:y
export ftp_proxy=http://x.x.x.x:y
export FTP_PROXY=http://x.x.x.x:y
</pre></blockquote>
<blockQuote>
'x.x.x.x' is the IP address of the proxy; 'y' is the proxy port.
</blockQuote>
<blockQuote>
Note that the "http://" part of the proxy location stays the same
even when you're defining an FTP proxy. Strange, but that's how it
works.
</blockQuote>
<blockQuote>
Again, this is only a possibility; you'd have to discuss the setup with
your system administrator to be sure.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [K.-H.] 
If that NT box is only running a proxy service for http that's all you get.
If on the other hand machines off sanrafael (IP probably 192.168.2.X ) have
full access (including ping, outside pop accounts, ftp,...) the NT box seems
to run a port-forwarding firewall ... or maybe merely ip masquerading...
and you should basically be able to do the
same -- <EM>IF</EM> the NT box is offering the service for 192.168.1.X.
</blockQuote>
<blockQuote>
What happens if you do all your tests from Charly?  Charly probably also
has no internet connection  (besides the http proxy).
</blockQuote>
<blockQuote>
Also for ftp through firewall make sure you run ftp in "passive" mode. For
ftp originally the server was opening a connection back to your client on a
different port -- which usually fails for through firewalls (so might not
fail with recent firewall port masquerading).
On a "recent" *nix ftp client typing "passive" before trying to "ls" or
get/put will do.
</blockQuote>
<blockQuote>
But I guess (like Ben) that the NT box is blocking you.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [John K.] 
Do you have DNS referencing (i.e., etc/resolve.conf) setup on CHARLY?
As K-H mentioned, it would seem that IP masquerading should be set up on
CHARLY if it isn't already.  You need to have the packets from the
192.168.2 subnet appear as 192.168.1 subnet packets to get the same
treatment from the NT server for the .2 subnet as it gives to the .1
subnet.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
Hello Gang!!!
Santyx again.
Thanks for your answers about "A LAN Question"
The net admin of my University made the changes in the sanrafael server,
and now I can do telnet from
my work station, but I can't do FTP.
When I connect to sanrafael doing FTP from Linux the proxy answer well,
the connection is done.
But the commands don't answer and I got to kill the connection from another
console.
It doesn't happens from windows.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [JimD] 
Try the same FTP connection using a web browser (even lynx, the
venerable text-mode curses or w3m, a newer curses mode browser).
</blockQuote>
<blockQuote>
If that works than you probably have a problem with your firewall
(or packet filters) that rejects "active" mode FTP connections.
</blockQuote>
<blockQuote>
In FTP the session you establish is a control channel, it's used to
send your FTP client's commands (you say "get" and your client changes
that to RETR, you say "ls" and your client sends 'LIST' or 'NLIST',
or whatever).   The response codes (numeric and text) are also returned
on this control channel (which is on destination port 21 on the server
from some unprivileged port on your client host).
</blockQuote>
<blockQuote>
In active FTP the FTP server attempts to create a data connection for
each stream of data that you get.  That includes each file that you
fetch, of course.  However it also includes connections for directory
listings.  The problem is that most firewalls and packet filters block
inbound connections (from the FTP server back towards your client) on
low numbered (privileged) ports.
</blockQuote>
<blockQuote>
With passive FTP the client specifies a non-privileged port (greater than
1024) for the data channels.  The back channel is still inbound from the
server back to the client.  The difference is that the client specificies
an available port (by sending a PORT command over the control connection).
That works with most packet filter configurations and firewalls.  However,
it won't necessarily work with all of them.
</blockQuote>
<blockQuote>
In most FTP clients you can set passive mode by typing a command like
"quote pasv" (in ncftp you can use the command "set passive").
</blockQuote>
<blockQuote>
If a web browser works using an ftp://.... url, then passive mode from
your FTP client should work as well.  Most web browsers default to
passive mode.  If passive mode doesn't work, then you may need to use
a proxy system.  I won't go into details on those --- you'd be best
checking with your local system/network administrator if you think you
need that.
</blockQuote>
<blockQuote>
Occasionally I've found other causes for the situation you describe.
However, they are much less likely.  In one case I found that it was
related to MTU (maximum transmission units).  Web and other traffic would
work, but FTP data connections would fail (apparently because it was
more likely to use maximum sized packets --- due to its socket options).
</blockQuote>
<blockQuote>
I doubt you'll encounter this sort of problem.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
I got another question.
It's about GNU Grub.
I've installed the 0.92 version to load win98 and Red Hat Linux 7.1
Everithing goes O.K, but I want to make a graphic menu and I can't.
I put the following line in the menu.lst to show a graphic file
</STRONG></P>

<pre><strong>splashimage=3D(hd0,1)/boot/grub/fun.xpm.gz
</strong></pre>
<P><STRONG>
Where (hd0,1) is the Linux partition and <TT>/boot/grub/fun.xpm.gz</TT> is the path
of the graphic file.
The image is 640x480, 4 colors.
</STRONG></P>
<P><STRONG>
But nothig happens.
How can I make my own menu for Grub?
</STRONG></P>
<P><STRONG>
Thanks again.
santyx
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Matthias] 
RedHat'S GRUB version has a splashimage patch applied. It can read XPM's
and display them. The patch and a vga-16 patch are available on the net
for GRUB 0.91, but not part of the standard GRUB package. So you have to
hunt down a patch for 0.92, apply and rebuild.
</blockQuote>

<!-- end 3 -->
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<A NAME="tag/4"><HR WIDTH="75%" ALIGN="center"></A>
<!-- begin 4 -->
<H3 align="left"><img src="../gx/dennis/qbubble.gif" 
	height="50" width="60" alt="(?) " border="0"
	>Homework question: defining subnets</H3>


<p><strong>From Darren Collins 
</strong></p> 


<p align="right"><strong>Answered By  Faber Fedor, Frank Rodolf, Jim Dennis
</strong></p>
<P><STRONG>
How do you specify the first 6 &amp; last 2 available subnets defined by the
IP address and subnet mask (155.25.0.0/23) Any help on this would be
greatly appreciated.
</STRONG></P>
<P><STRONG>
Sincerly, Darren
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Faber] 
How do I?  Very well, actually.  I usually use a calculator, but using
an abacus is much more challenging!
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Frank] 
But doing it by hand is more fun!
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Faber] 
Have you looked here <A HREF="http://www.learntosubnet.com"
	>http://www.learntosubnet.com</A> ?
</blockQuote>
<blockQuote>
BTW, we don't do homework assignments around here, except for our own,
of course.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [JimD] 
The reason we know it's a homework assignment is because no one uses
this scheme in the real world.  This would define 126 subnets of
510 hosts each (or 128 subnets --- with modern equipment).  The first
subnets would be 155.25.0.* <EM>AND</EM> 155.25.1.*; the next would be
.2.* and .3.*; etc.
</blockQuote>
<blockQuote>
This is a bit-aggregation (supernetting) over the traditional "class
C" sized network.  Normally people would go for a 4-bit aggregation
--- giving them 16 networks of about 4000 hosts each (and possibly
fanning those into class C sized networks through another hierarchical
layer of routers).
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Frank] 
Actually, there are real world exceptions to the 4-bit aggregation.
The multinational I am working at nowadays uses a 21-bit mask on a lot
of sites. (And it still has me confused at times.)
</blockQuote>

<!-- end 4 -->
<!--     .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.     -->
<A NAME="tag/5"><HR WIDTH="75%" ALIGN="center"></A>
<!-- begin 5 -->
<H3 align="left"><img src="../gx/dennis/qbubble.gif" 
	height="50" width="60" alt="(?) " border="0"
	>thx for ur ncurses, u have networking howto?</H3>


<p><strong>From deepak a.l 
</strong></p> 

<p align="right"><strong>Answered By  Pradeep Padala, Heather Stern
</strong></p>

<blockquote><em><font color="#000066">The original subject had been:
</font></em></blockquote>
<blockquote><em><font color="#000066">hi mr pradeep padala need help free source code for a networking project under linux topics like ppp
 -- Heather</font></em></blockquote>
<P><STRONG>
hi pradeep padala
</STRONG></P>
<P><STRONG>
im deepak from bangalore , a very
good lover of linux and its extra features ,me and my
batch mate  are doing a project on "networking using
linux as a platform"" plese help me out regarding this
regard,ur howto ncurses programming helped us a lot
for building up the editor,thanks for the ncurses
programming ,it was helpful ,
</STRONG></P>
<P><STRONG>
so i wanted to ask u whether u have "Networking Howto"
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Pradeep] 
A wealth of information is available regarding networking on Linux. If you
want a generic introduction to networking, TLDP (The LinuxDoc Project) has
following howtos
</blockQuote>
<blockQuote><DL><DT>
Net-Howto:
<DD><A HREF="http://www.tldp.org/HOWTO/Net-HOWTO/index.html"
	>http://www.tldp.org/HOWTO/Net-HOWTO/index.html</A>
</DL></blockQuote>
<blockQuote><DL><DT>
Networking-Howto:
<DD><A HREF="http://www.tldp.org/HOWTO/Networking-Overview-HOWTO.html"
	>http://www.tldp.org/HOWTO/Networking-Overview-HOWTO.html</A>
</DL></blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Heather] 
Also within the pages of the Linux Gazette itself, the very long Jim
Dennis message "Routing and Subnetting 101" is still available:
<A HREF="../issue36/tag/a.html"
	>http://www.linuxgazette.com/issue36/tag/a.html</A>
</blockQuote>
<blockQuote>
We have had other good messages on networking topics too.  These are
mentioned in the Answer Gang Knowledgbase:
<A HREF="../tag/kb.html"
	>http://www.linuxgazette.com/tag/kb.html</A>
</blockQuote>
<blockQuote>
While most of the questions asked of us are about configuring the
network to be visible, certain kinds of questions lead to a discussion
of how it works under the hood.  Many are laden with additional URLs
well worth reading into.   But I'd say a fair number of them mention the
HOWTOs that Pradeep listed above.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
plese help us out ,we want to do well in our project
with ur wishes, plese let me know as soon as possible
of networking projects sites offering free source code
or any thing tutorial written by u regarding
networking under linux, i mean the manpages which
display help for networking,
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Pradeep] 
I guess you are looking for information on socket programming. There are
tons of tutorials on net. The man pages must be available on your linux
system. I am forwarding a mail I wrote answering a similar question.
</blockQuote>
<blockQuote>
For source code you can have a look at various projects at
<A HREF="http://freshmeat.net"
	>http://freshmeat.net</A> and
<A HREF="http://sourceforge.net"
	>http://sourceforge.net</A>
</blockQuote>
<blockQuote>
Good luck
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
we would be really
thankful to u if u please help us in this regard
i mean if u have a documentation or example source
code which could help us in building the networking
project ,please suggest me some sites reagading
networking,pleaseeeee
</STRONG></P>
<P><STRONG>
regards
</STRONG></P>
<P><STRONG>
deepak
sanjay
</STRONG></P>
<P><STRONG><CODE>
from Bangalore
</CODE></STRONG></P>
<P><STRONG>
thank u!!!
</STRONG></P>

<TABLE WIDTH="95%" BORDER="1" BGCOLOR="#FFFFCC"><TR><TD>
<p align="center">...............</p>
<P><STRONG>
Forwarded Message
</STRONG></P>
<P><STRONG>
can u tell me how the data packets are sent from
</STRONG></P>
<P><STRONG>
one pc to other in a LAN. in other words about the tcp
ip in linux. lastly if u have any code in c or cpp to
do this job.
</STRONG></P>
<P><STRONG>
That's quite a broad question. Gurus like Richard Stevens, Douglas E
Comer wrote atleast three volumes each on this topic. I suggest you read
Richar Stevens' "UNIX Network Programming" book.
</STRONG></P>
<P><STRONG>
If you want to know about socket programming(I guess that's what you mean
by c code), there are plenty of articles on web. Google.com is the best
place to search. This is one of the articles I found
</STRONG></P>
<P><STRONG>
<A HREF="http://www.scit.wlv.ac.uk/~jphb/comms/sockets.html"
	>http://www.scit.wlv.ac.uk/~jphb/comms/sockets.html</A>
</STRONG></P>
<P><STRONG><DL><DT>
There's a TCP/IP resource list on faqs.org:
<DD><A HREF="http://www.faqs.org/faqs/internet/tcp-ip/resource-list"
	>http://www.faqs.org/faqs/internet/tcp-ip/resource-list</A>
</DL></STRONG></P>
<P><STRONG>
If you want to learn how TCP/IP implementation in Linux, best way to do is
to look through source which can be browsed online at <A HREF="http://lxr.linux.no"
	>http://lxr.linux.no</A>.
Apart from that, the following document can give you some info
</STRONG></P>
<P><STRONG>
<A HREF="http://www.cs.unh.edu/cnrg/gherrin"
	>http://www.cs.unh.edu/cnrg/gherrin</A>
</STRONG></P><p align="center">...............</p>
</TD></TR></TABLE>

<!-- end 5 -->
<!--     .~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.~~.     -->
<A NAME="tag/6"><HR WIDTH="75%" ALIGN="center"></A>
<!-- begin 6 -->
<H3 align="left"><img src="../gx/dennis/qbubble.gif" 
	height="50" width="60" alt="(?) " border="0"
	>How to kill a process in uninterruptible sleep state?</H3>


<p><strong>From Carlos Garada 
</strong></p> 

<p align="right"><strong>Answered By  John Karns, Ben Okopnik, Karl-Heinz Herrmann, Jay R. Ashworth, Robos,
 Jim Dennis, Ashwin N
</strong></p>
<P><STRONG>
Dear answer gang:
</STRONG></P>
<P><STRONG><BLOCKQuote>
Sometimes when I mount a CD, mount hangs. ps shows it is
in an "uninterruptible sleep", and kill won't kill it. As a
result, I can not access my CD drive until I restart my computer.
</BLOCKQuote></STRONG></P>
<P><STRONG>
Is there a way to kill a process in uninterruptible sleep?
</STRONG></P>
<P><STRONG>
Thanks!
</STRONG></P>
<P><STRONG>
C. Garada
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [John K.] 
What I usually do is to kill the parent process, which is usually a bash
shell.  In many <TT>/</TT> most cases this allows killing of the errant process.
However, you may run into the situation where the driver or a port is
hung.  In those cases, you may have no choice but to reboot.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
Sometimes the parent process is apt-get. I kill it, but the spawned
mount remains in state "D" and I can not kill it.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Ben] 
Have you tried "kill -9"? This is not a good thing to do by default. but
if you've already tried a plain "kill" (which issues a "-15"), that's
what's left. See "man kill" for more details.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
Yes, I tried kill -9 and fuser -k <TT>/cdrom/...</TT> Nothing works.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [jra] 
Nope, they won't.  They only work on processes sleeping above priority
PZERO (if I remember the terminology correctly).  The problem your
having is almost certainly coming from a process sleeping <EM>below</EM> PZERO
-- which is almost always a device driver with either bad hardware, or
a bug.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Ben] 
Yep, those are the correct terms; however, I believe that the only
processes below PZERO are zombies. I think what happens with fast
devices is simply a loop that's too "tight" to break into, fast and
straight to hardware without any intervening layers that would allow a
signal to "break in".
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
I suppose the mount(2) syscall is having a problem... but shouldn't I
be able to interrupt a system call in some way?
</STRONG></P>
<P><STRONG>
Thank you for your answers.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [jra] 
A system call, yes.  But not necessarily inside a driver call.
</blockQuote>
<blockQuote>
Tape drives are famous for this... they seem to be implemented as fast
devices, even though they manifestly are not.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [John K.] 
And that is the one situation that comes to mind where I experienced the
problem - using a SCSI tape drive and encountering a read or write error,
the process would hang.  I was unable to kill the process directly, but
was more successful in killing the parent process.  But I also encountered
situations where the SCSI driver for the PCMCIA card hung, and the only
way I could clear it was a reboot.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
So reboot is the
only answer? The almighty root can not do anything? 
<IMG SRC="../gx/dennis/unsmily.gif" ALT=":(" 
		height="24" width="20" align="middle">
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [jra] 
Nope.  There are some things even root can't do.  There's fairly
extensive discussion of this in a couple of the kernel design books,
and I <EM>think</EM> in Nemeth, Snyder and Seebass: the problem stems from the
fact that there are two types of device drivers -- those for "fast"
devices and those for "slow" devices.
</blockQuote>
<blockQuote>
Slow-device drivers -- for things like terminals, and such -- are
usually split in two pieces, and can therefore be interrupted while
they're in the middle of something.
</blockQuote>
<blockQuote>
Fast-device drivers -- which service things like hard drives and
(I think) ethernet cards -- are designed to expect that when they call
out to hardware, it will respond instantly (in human terms), and that
they won't have to wait on anything.  Such drivers have, as a rule,
proven extremely intolerant of hardware trouble -- if your hard drive
start having to do hardware retries to read a sector, your system
perfromance is going int he toilet, even if you have more than one
drive...
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
Thank you for your explanation, Jay. So I suppose I should either resign
myself to rebooting every time it happens, or rewrite the driver...
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Robos] 
Have you ever tried to wait really long (in human terms 
<IMG SRC="../gx/dennis/smily.gif" ALT=";-)" 
		height="24" width="20" align="middle">, something in
the range of 30mins or so? I think I had a case when my cd hung and I simply
continued with something else and - yo and behold - after that the cd worked
again. But I'm not sure anymore.
</blockQuote>
<blockQuote>
Hope this helps.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Ben] 
Oh - good point, Robos. I've had things like that happen... Midnight
Commander trying to read "<TT>/dev/fd0</TT>" with a bad floppy from an LS120
drive comes to mind, but that was way back when. Took about 10 minutes
to stop generating console errors (about two per minute), even after MC
(<EM>and</EM> the parent shell!) were killed; it had to have been from the
kernel is my guess. Rare, but I've seen it.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
A day and a half... and then lost my patience 
<IMG SRC="../gx/dennis/smily.gif" ALT=":)" 
		height="24" width="20" align="middle">.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Robos] 
THAT short ? Sissy 
<IMG SRC="../gx/dennis/smily.gif" ALT=";-)" 
		height="24" width="20" align="middle">)
</blockQuote>

<blockquote><em><font color="#000066">Hunh. Robos may not be impressed, but <EM>I</EM> am.
 -- Heather</font></em></blockquote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [jra] 

<IMG SRC="../gx/dennis/smily.gif" ALT=":-)" 
		height="24" width="20" align="middle">
</blockQuote>
<blockQuote>
One thing we haven't mentioned here...
</blockQuote>
<blockQuote>
Occasionally, you'll get lucky, and rmmod will permit you to remove
whichever module supports the device you're having trouble with... and
then your stuck process will go away.  I've had luck with this,
particularly, on the SCSI CD-R attached to my laptop with an Adaptec
APA-1460 PCMCIA card...
</blockQuote>
<blockQuote>
Now, that <EM>could</EM> be because PCMCIA busses are natively hot-pluggable,
but...
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [JimD] 
A process which ends up in "D" state for any measurable length of
time is trapped in the midst of a system call (usually an I/O
operation on a device --- thus the initial in the ps output).
</blockQuote>
<blockQuote>
Such a process cannot be killed --- it would risk leaving the
kernel in an inconsistent state, leading to a panic.  In general
you can consider this to be a bug in the device driver that the
process is accessing.
</blockQuote>
<blockQuote>
Once case that I can't consider to be a Linux bug occurs when
one is attempting to access a hard mounted NFS exported share
without the intr (mount(
<IMG SRC="../gx/dennis/smily.gif" ALT="8)" 
		height="24" width="20" align="middle">) flag.  If the NFS server (or the network
connection thereto) becomes unavailable all processes that try to
access any part of that share will be set into D state.  (Use intr or
soft mount options on NFS to avoid all that).  I might consider that to
be a design bug in the NFS protocol --- but that might be contentious.
That particular NFS behavior can actually be a feature in some cases;
I think it should NOT be the default, though.
</blockQuote>
<blockQuote>
When it comes to scsi and similarly local device drivers --- I would
report cases of "D" state as bugs (after due diligence of checking
for prior reports, updates, and perhaps trying to troubleshoot it a
bit).
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
Where? In the linux kernel mailing list?
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [jra] 
You're welcome.  Could you recap one more time, in about a sentence,
exactly what's hanging and when?  Jim's right: if this is repeatable,
the kernel wonks would like to hear about it.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
Sometimes, when I mount the cdrom, mount hangs and I can not kill
it; and I can not access the cdrom either. Ah, and the door remains
closed and I can not open it.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Ben] 
I'll back Carlos' report; I've seen this before, although not in the
past... erm, for sure since I've been using 2.4.18 and maybe even well
before that, but my memory refuses to pony up. Seems like it was in the
past three years, though.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
How to reproduce it: I don't know 
<IMG SRC="../gx/dennis/unsmily.gif" ALT=":(" 
		height="24" width="20" align="middle">. I tried hard yesterday but this
bug won't show when I want it to.
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Ben] 
ISTR that a damaged (boot/signature sector damage) CD would do it pretty
much every time. I've got about 50% confidence in this memory, but
there's something in the back of my brain that's hinting thataway.
</blockQuote>
<P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> 
Kernel 2.4.17.
</STRONG></P>
<P><STRONG>
Ah, and maybe important (I only thought of this now, sorry): I have
a binary kernel module and a binary X server (not source available) for
my nVidia graphics card. Maybe they are corrupting the memory and this
affects the driver(?)? I know these binary components are not very good
because the computer hangs on some GL screensavers... but I never
thought they could make the ide/cdrom/whatever drive go wrong.
</STRONG></P>
<P><STRONG>
Could that be the problem?
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Ben] 
FTR, neither of the above apply to me.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Ashwin N] 
Similar things used to happen to me with a faulty CDROM drive.
</blockQuote>
<blockQuote>
If this problem happens only with the CDROM drive, then <em> _maybe</em> the
drive is faulty. If you have 'the other OS' you could boot it up and put
in a CD and check for similar symptoms.
</blockQuote>

<blockquote><em><font color="#000066">I don't believe I've ever seen this sort of wedge on a CD-ROM drive but
I have seen it happen to a PCMCIA card -- a NIC interface that was too
new, and being spotted as the wrong card.  Luckily I could ignore that
until I felt inclined for a reboot for some other reason.
</font></em></blockquote>
<blockquote><em><font color="#000066">Oh yeah,
since your troubles include a mountpoint -- walk through your shutdown
sequence by hand.  You'll find 'umount -a' is not going to behave itself

<IMG SRC="../gx/dennis/unsmily.gif" ALT=":(" 
		height="24" width="20" align="middle">
 -- Heather</font></em></blockquote>
<HR width="10%" align="left"><P><STRONG>
<IMG SRC="../gx/dennis/qbub.gif" ALT="(?)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [John K.] 
I have a related problem when resuming from APM suspend on my laptop.
Since I updated the BIOS it resumes without hanging as it used to do, but
the NIC (eepro100) doesn't get reset; and unloading <TT>/</TT> reloading the NIC
driver doesn't help, so I'm stuck with rebooting if I want to connect to a
LAN after suspending.
</STRONG></P>
<P><STRONG>
{{{
John, have you tried unplugging/reinserting the card (I'm assuming it's
PCMCIA)? That's what used to work for me when this happened back in the
2.2 kernel.
{{{{
</STRONG></P>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [John K.] 
No, unfortunately it's integrated - never thought that there would be an
advantage to PCMCIA vs integrated, but I guess that's one.  I have three
PCMCIA cards that I bought to use with previous machines - two Xircom
ether <TT>/</TT> modem combos and a 3Com ether only.  One of the Xircoms is 10/100
ether the other 10.  Both really heat up, which exacerbates the internal
heat problem considerably especially in warmer climates.  I get nervous
when the bottom of the CD/DVD drawer gets too hot to touch.  OTOH the 3Com
stays pretty cool most of the time.
</blockQuote>
<blockQuote>
A while ago someone told me that there was talk of the eepro100 reset
problem on the kernel dev list, and that there may a patch or fix for it -
maybe in the 2.4 kernel.  I'm still using 2.2 kernel, mainly because of
VMWare - will have to re-install the MSW I have setup in virtual
partitions - something that I've been putting off until I have enough time
to deal with it all.
</blockQuote>
<blockQuote>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [K.-H.] 
If Vmware is what's keeping you from going to 2.4 and you would like to
switch -- there is at least a patch for vmware 2.x to make it work beyond
kernel 2.4.6.
</blockQuote>
<blockQuote>
<A HREF="http://volker.orcon.net.nz/linux/vmware/vmware2.0.4-SuSE7.3.txt"
	>http://volker.orcon.net.nz/linux/vmware/vmware2.0.4-SuSE7.3.txt</A>
</blockQuote>

<!-- end 6 -->
<P> <hr> </p>
<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>
<h5>
<br>Copyright &copy; 2002
<br>Copying license <A HREF="">http://www.linuxgazette.com/copying.html</A>
<BR>Published in Issue 83 of <i>Linux Gazette</i>, October 2002</H5>
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
<HR>


<TABLE BORDER><TR><TD WIDTH="200">
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	WIDTH="200" HEIGHT="41" border="0"></A> 
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD WIDTH="380">


<center>
<BIG><BIG><STRONG><FONT COLOR="maroon">News Bytes</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/conry.html">Michael Conry</A></STRONG></BIG>

</TD></TR>
</TABLE>
<P>

<!-- END header -->





<center>
<table cellpadding=7><tr><td>
<IMG SRC="../gx/bytes.gif" border=1  ALT="News Bytes">
</td><td>
<H3>Contents:</H3>
<ul>
<li><a HREF="#leg">Legislation and More Legislation</a>
<li><a HREF="#links">Linux Links</a>
<li><a HREF="#conferences">Conferences and Events</a>
<li><a HREF="#general">News in General</a>
<li><a HREF="#distro">Distro News</A>
<li><a HREF="#commercial">Software and Product News</a>
</ul>
</td></tr></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> 
<!-- =================================================================== -->

<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<font color="green">
October 2002 <I>Linux Journal</I>
</font>
</H3>

<IMG ALT="[issue 102 cover image]"   SRC="misc/bytes/lj-cover102.png" WIDTH=200 HEIGHT=268 
ALIGN="left" HSPACE="20">

The October issue of <A HREF="http://www.linuxjournal.com/"><I>Linux
Journal</I></A> is on newsstands now.
This issue focuses on Security.  Click 
<A HREF="http://www.linuxjournal.com/modules.php?op=modload&name=NS-lj-issues/issue100&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">Venezuela and Other Government News
</FONT>
</H3> 
<P>
The Register
<a href="http://www.theregister.co.uk/content/4/26928.html">
reported</a> that
Venezuela has adopted a pro-GPL policy for government software.
All software developed for the government must be GPL, and GPL is preferred
for off-the-shelf software.  As described in 
<a href="http://linuxtoday.com/news_story.php3?ltsn=2002-08-30-011-26-NW-LL-PB">
LinuxToday's coverage</a>, it would appear that Dr. Felipe P&eacute;rez-Mart&iacute;,
Venezuelan Planning and Development Minister is well acquainted with
open-source, free software and the ideas behind these buzz words.
<P>
Use of Open Source has also been
<a href="http://www.itweb.co.za/sections/computing/2002/0209091122.asp?A=">
recommended by a South African Government Advisory body</a>.  The
Ukrainian government is also considering 
<a href="http://newsvac.newsforge.com/article.pl?sid=02/09/02/1226244&mode=thread&tid=51">
expressing legal preferences for open source solutions</a>.
<P>
On a third front,
the UK Commission on Intellectual Property Rights, has 
<a href="http://www.iprcommission.org/papers/text/final_report/reportwebfinal.htm">
concluded</a>
that open source and avoidance of restrictive licensing conditions is 
<a href="http://news.zdnet.co.uk/story/0,,t269-s2122219,00.html">
essential to developing countries future progress</a>.
This report was also covered
<a href="http://lwn.net/Articles/10278/">
by Linux Weekly News</a>
and 
<a href="http://economist.com/science/displayStory.cfm?story_id=1325219">
by the Economist</a>.

<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">FSF changes focus
</FONT>
</H3> 
<P>
NewsForge 
<a href="http://newsforge.com/newsforge/02/09/24/182213.shtml?tid=51">
has reported</a> that
<a href="http://www.fsf.org/">
The Free Software Foundation</a>
is changing its priorities to focus less on development, and to concentrate
more on fighting digital rights management and enforcing the GPL.  At the
same time, Richard Stallman is planning to take a lower profile role in the
organization.
<P>
Richard Stallman has 
<a href="http://www.theregister.co.uk/content/4/27121.html">
recently written</a>
on the issues of open-source, free software, and security.
The article takes the form of an open letter responding to an earlier
contribution by SecurityFocus' Jon Lasser. He asserts the importance of
being mindful of the very  political underpinnings of free software, and
<a href="http://www.gnu.org/philosophy/free-software-for-freedom.html">
the differences</a>
between what is meant by the terms <em>free software</em>
and <em>open source software</em>.
Now, if only we could all 
<a href="http://www.gnu.org/gnu/gnu-linux-faq.html">
remember to say</a> GNU/Linux!

<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">Palladium
</FONT>
</H3> 
<P>
Two documents worth reading regarding Microsoft's Palladium project, and
potential future ramifications are
the guides written 
<a href="http://www.cl.cam.ac.uk/~rja14/tcpa-faq.html">
by Ross Anderson</a>
and
<a href="http://vitanuova.loyalty.org/2002-07-05.html">
by Seth Schoen</a>.

<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">Adobe Bitten by DMCA
</FONT>
</H3> 
<P>
Linux Weekly News
<a href="http://lwn.net/Articles/8776/">
have a commentary</a> on an ironic development whereby Adobe is being
attacked using the DMCA for a feature included in Acrobat which could be
construed.  Meanwhile, Wired report that Elcomsoft have not allowed their
DMCA difficulties to cramp their style and are continuing to 
<a href="http://www.wired.com/news/business/0,1367,54712,00.html">
sail perilously close to the wind</a> in their software development.
<P>
While on the topic of the DMCA, Robert Cringely
<a href="http://www.pbs.org/cringely/pulpit/pulpit20020919.html">
has published an interview</a> with
Mark Ishikawa, a prominent enforcer of the DMCA.
Also of interest is LawMeme's 
<a href="http://research.yale.edu/lawmeme/modules.php?name=News&file=article&sid=319">
dissection</a>
of Cornell's DMCA Policy (<a href="http://newsvac.newsforge.com/article.pl?sid=02/09/05/0326222&mode=thread&tid=19">courtesy NewsForge</a>).




<a name="links"></a>
<p><hr><p>
<!-- =================================================================== -->
<center><H3><font color="green">Linux Links</font></H3></center>
<p>
Some links of particular interest from the O'Reilly stable of websites:
<ul>
    <li>
        Configuring sound for 
        <a href="http://linux.oreillynet.com/pub/a/linux/2002/09/19/linuxlaptop.html">
        Linux on a Laptop</a>.
    </li>
    <li>
        <a href="http://www.oreillynet.com/pub/wlg/1982">
        Interesting quotes</a>
        from experts on the issues of copyright law and fair use.
    </li>
    <li>
        <a href="http://linux.oreillynet.com/pub/a/linux/2002/08/29/howardwen.html">
        Roll Your Own Digital Video Recorder</a>:
        Video Disk Recorder, or VDR, is a user interface for building a 
        digital satellite TV receiver and recorder box running under 
        Linux.  
    </li>
    <li>
        <a href="http://www.oreillynet.com/pub/a/mozilla/2002/09/12/mozilla_browsers.html">
        Let One Hundred Browsers Bloom</a>, and a sample chapter from
        <a href="http://www.oreilly.com/catalog/mozilla/chapter/index.html">
        Creating Applications with Mozilla</a>.
    </li>
    <li>
        Michael Lucas
        <a href="http://www.onlamp.com/pub/a/bsd/2002/09/12/Big_Scary_Daemons.html">
        shows how to simplify sudo maintenance</a>
        and clean up your sudo configuration using aliases.  Also of interest
        is the 
        <a href="http://www.onlamp.com/pub/a/bsd/2002/08/29/Big_Scary_Daemons.html">
        preceding article</a>.
    </li>
    <li>
        <a href="http://www.oreillynet.com/pub/a/network/2002/09/24/essentialsysadmin.html">
        Top Five Open Source Packages for System Administrators</a>.
    </li>
</ul>
<P>
Some links from <a href="http://lwn.net/">Linux Weekly News</a>:
<ul>
    <li>
        The LWN subscription department 
        <a href="http://lwn.net/Articles/10688/">
        is now open for business</a>.
    </li>
    <li>
        <a href="http://lwn.net/Articles/8284/">
        LWN defends Red Hat</a>
        against accusations that it's becoming "the Microsoft of Linux".
    </li>
    <li>
        LWN's John Corbet 
        <a href="http://lwn.net/Articles/9185/">
        runs SpamAssassin and bogofilter on 8000 e-mail messages</a>
	to see which program is faster, easier, and more correct.  Also looks
	at open source and public election systems.
    </li>
    <li>
        <a href="http://www.newsalert.com/bin/story?StoryId=CpxBwWaicu0qTq09nufvurvjt&Print=1">
        Microtel/Lindows computer for $199</a> without monitor at Wal-Mart.
    </li>
</ul>
<P>
Some links from <a href="http://slashdot.org/">Slashdot</a> which might be
of interest:
<ul>
    <li>
        <a href="http://ask.slashdot.org/article.pl?sid=02/09/10/2028215&mode=nested&tid=158">
        Review of liberties lost in the United States</a> in recent months.
    </li>
    <li>
        <a href="http://slashdot.org/article.pl?sid=02/09/05/1457245&mode=nested&tid=106">
        Slashdot reported</a>
        that 
        <a href="http://www.bcg.com">
        The Boston Consulting Group</a>
        with 
        <a href="http://www.osdn.com">OSDN</a>
        have been
        <a href="http://kernelmapper.osdn.com">
        working on a visual representation</a>
        of the Linux Kernel, and have now made it available online
    </li>
    <li>
        <a href="http://slashdot.org/article.pl?sid=02/09/09/0045223&mode=nested&tid=141">
        Slashdot story</a> on the 
        <a
        href="http://www.heise.de/newsticker/data/anw-08.09.02-000/">success</a>
        [in German]
        of the 
        <a href="http://www.xiph.org/ogg/vorbis/">Ogg Vorbis</a>
        audio codec in a blind test of 6000 users.
    </li>
    <li>
        <a href="http://yro.slashdot.org/yro/02/09/26/145220.shtml?tid">
        Slashdot thread</a> discussing 
        a two part
        (<a href="http://www.desktoplinux.com/articles/AT3341468184.html">I</a>
        and 
        <a href="http://www.desktoplinux.com/articles/AT7966076367.html">II</a>)
        Introduction to 
        <a href="http://www.gnupg.org/">GnuPG</a>
        (Gnu Privacy Guard).
    </li>
    <li>
        Pedal-powered Linux-based wireless network 
        <a href="http://www.80211-planet.com/columns/article/0,4000,1781_1454991,00.html">
        bring Internet access to Laotian villages</a> that have no electricity or phones
    </li>
    <li>
        <a href="http://developers.slashdot.org/developers/02/09/12/236213.shtml?tid6">
        Linux 2.5.34 includes User Mode Linux (UML)</a>.  
        <a href="http://user-mode-linux.sourceforge.net/">UML</a> is a way
        to run an instance of Linux in a virtual machine.  It enables
        <a href="http://linux.oreillynet.com/pub/a/linux/2001/11/29/UserModeLinux.html">
        cutting-edge experimentation without hosing your host system</a>.
    </li>
    <li>
        <a href="http://slashdot.org/articles/02/09/04/1328209.shtml?tid9">
        A Linux set-top box by Sony</a>
        with a broadband Internet connection.
        It's available only in Japan, but you can
        <a href="http://www.watch.impress.co.jp/av/docs/20020904/sony.htm">
        see pictures here</a> (and read more about it too, if you can read
        Japanese).
        This story was also
        <a href="http://www.reuters.com/news_article.jhtml?type=technologynews&StoryID=1407280">
        reported by Reuters</a>.
        Another company which has been 
        <a href="http://newsvac.newsforge.com/article.pl?sid=02/09/05/175221&mode=thread&tid=23">
        pushing Linux for consumer electronics applications</a>
        is <a href="http://www.philips.com/">Philips</a>.
    </li>
    <li>
        Andy's legion of Lego men
        <a href="http://lego.dave.dk/">
        assemble a computer</a>.
    </li>
</ul>


<P>
<a href="http://rpm.pbone.net/">
RPM PBone</a> is a 
searchable index of RPMs, and an alternative to <a
href="http://rpmfind.net">Rpmfind</a>.
<P>
Salon report on how recycled PC's can be a tool of
<a href="http://www.salon.com/tech/feature/2002/09/23/antiglobal_geeks/">
anti-globalization and empowerment</a>.
<P>
Moblix.org have released a 
<a href="http://mobilix.org/Infrared-HOWTO/Infrared-HOWTO.html">
Linux Infrared-HOWTO</a>,
providing an introduction to Linux and infrared devices and to the software
from the Linux/IrDA project.
<P>
OSNews 
<a href="http://www.osnews.com/story.php?news_id=1733">
article on Gentoo Linux</a>.
<P>
Some links from
<a href="http://www.linuxjournal.com/">
<em>Linux Journal</em></a>
<ul>
    <li>
        Using Gnu Emacs and Calc for 
        <a href="http://www.linuxjournal.com/article.php?sid=5873">
        engineering and mathematical reports</a>
    </li>
    <li>
        <a href="http://www.linuxjournal.com/article.php?sid=5653">
        RAID-1 HOWTO, Part 1</a> and
        <a href="http://www.linuxjournal.com/article.php?sid=5898">
        Part 2</a>:
        What it is, when to use it, how to make a RAID-1 device for an ext2 partition.
    </li>
    <li>
        Philip Streck
        <a href="http://www.linuxjournal.com/article.php?sid=6035">
        explains how to use devfs</a>, written as a virtual filesystem
        driver, to manage and administer access to /dev.
    </li>
    <li>
        A look at
        <a href="http://www.linuxjournal.com/article.php?sid=6153">
        running Microsoft Office 97 and 2000</a> on Linux using Codeweaver's
        Crossover Office product.
    </li>
    <li>
        And from the commercial end of things: SSC's new 16-page reference
        card on MySQL, written by database specialist Dan Wilder, is for
        sale for $4.95 on-line
        <a href="http://store.linuxjournal.com/">
        at the Linux Journal Store</a>.
    </li>
</ul>

<P>
Some links from <a href="http://www.theregister.co.uk/">The Register</a>:
<ul>
    <li>
        Xbox Linux Project 
        <a href="http://www.theregister.co.uk/content/4/26932.html">
        gets SuSE 8.0 running</a>.
        and 
        <a href="http://www.theregister.co.uk/content/4/26995.html">
        releases SuSE 8.0 howto</a>.
    </li>
    <li>
        PGP creator 
        <a href="http://www.theregister.co.uk/content/6/27078.html">
        joins UK privacy watchdog</a>.
    </li>
    <li>
        EU data protection chiefs 
        <a href="http://www.theregister.co.uk/content/6/27155.html">
        oppose data retention moves</a> on grounds of cost, practicality,
        and invasiveness.
    </li>
    <li>
        The Register 
        <a href="http://www.theregister.co.uk/content/4/26788.html">
        comments</a>
        on the UK's implementation of the "European DMCA", the European Union
        Copyright Directive (EUCD).
    </li>
</ul>






<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.

<!-- *** BEGIN events table [this line needed by Linux Gazette events.py *** -->

<table cellpadding=5 border=0 width=100%>

<tr><td valign=top>
        <b>O'Reilly Mac OS X Conference</b><BR>
        <td valign=top>September 30 - October 3, 2002<BR>Santa Clara, CA<BR>
        <a href="http://conferences.oreillynet.com/macosx2002/" target="_blank">
        http://conferences.oreillynet.com/macosx2002/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>IBM eServer pSeries (RS/6000) and Linux Technical University</b><BR>
        <td valign=top>October 14-18, 2002<BR>Dallas, TX<BR>
        <a href="http://www-3.ibm.com/services/learning/conf/us/pseries/" 
target="_blank">
        http://www-3.ibm.com/services/learning/conf/us/pseries/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>SANS Network Security</b><BR>
        <td valign=top>October 18-25, 2002<BR>Washington, DC<BR>
        <a href="http://www.sans.org/" target="_blank">
        http://www.sans.org/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>Strictly Business Solutions Expo</b><BR>
        <td valign=top>October 23-24, 2002<BR>Houston, TX<BR>
        <a href="http://www.strictlyebusiness.net/" target="_blank">
        http://www.strictlyebusiness.net/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>Third LCI International Conference on Linux Clusters: The 
Linux HPC Revolution</b><BR>
        <td valign=top>October 23-25, 2002<BR>St. Petersburg, FL<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>USENIX 16th Systems Administration Conference (LISA)</b><BR>
        <td valign=top>November 3-8, 2002<BR>Philadelphia, PA<BR>
        <a href="http://www.usenix.org" target="_blank">
        http://www.usenix.org/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>SuperComputing 2002</b><BR>
        <td valign=top>November 16-22, 2002<BR>Baltimore, MD<BR>
        <a href="http://www.sc2002.org/" target="_blank">
        http://www.sc2002.org/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>COMDEX</b><BR>
        <td valign=top>November 18-22, 2002<BR>Las Vegas, NV<BR>
        <a href="http://www.comdex.com/fall/" target="_blank">
        http://www.comdex.com/fall/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>SD East</b><BR>
        <td valign=top>November 18-22, 2002<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>USENIX 5th Symposium on Operating Systems Design
        and Implementation (OSDI)</b><BR>
        <td valign=top>December 9-11, 2002<BR>Boston, MA<BR>
        <a href="http://www.usenix.org" target="_blank">
        http://www.usenix.org/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>Consumer Electronics Show</b><BR>
        <td valign=top>January 9-12, 2003<BR>Las Vegas, NV<BR>
        <a href="http://www.cesweb.org/" target="_blank">
        http://www.cesweb.org/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>LinuxWorld Conference & Expo</b><BR>
        <td valign=top>January 21-24, 2003<BR>New York, NY<BR>
        <a href="http://www.linuxworldexpo.com" target="_blank">
        http://www.linuxworldexpo.com</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>O'Reilly Bioinformatics Technology Conference</b><BR>
        <td valign=top>February 3-6, 2003<BR>San Diego, CA<BR>
        <a href="http://conferences.oreilly.com/" target="_blank">
        http://conferences.oreilly.com/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>Game Developers Conferenc</b><BR>
        <td valign=top>March 4-8, 2003<BR>San Jose, CA<BR>
        <a href="http://www.gdconf.com/" target="_blank">
        http://www.gdconf.com/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>SXSW</b><BR>
        <td valign=top>March 7-11, 2003<BR>Austin, TX<BR>
        <a href="http://www.sxsw.com/interactive" target="_blank">
        http://www.sxsw.com/interactive</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>COMDEX Canada</b><BR>
        <td valign=top>March 11-13, 2003<BR>Vancouver, BC<BR>
        <a href="http://www.comdex.com/vancouver/" target="_blank">
        http://www.comdex.com/vancouver/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>CeBIT</b><BR>
        <td valign=top>March 12-19, 2003<BR>Germany<BR>
        <a href="http://www.cebit.de/" target="_blank">
        http://www.cebit.de/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>4th USENIX Symposium on Internet Technologies and Systems</b><BR>
        <td valign=top>March 26-28, 2003<BR>Seattle, WA<BR>
        <a href="http://www.usenix.org/events/" target="_blank">
        http://www.usenix.org/events/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>AIIM</b><BR>
        <td valign=top>April 7-9, 2003<BR>New York, NY<BR>
        <a href="http://www.advanstar.com/" target="_blank">
        http://www.advanstar.com/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>SD West</b><BR>
        <td valign=top>April 8-10, 2003<BR>Santa Clara, CA<BR>
        <a href="http://www.sdexpo.com/" target="_blank">
        http://www.sdexpo.com/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>COMDEX Chicago</b><BR>
        <td valign=top>April 15-17, 2003<BR>Chicago, IL<BR>
        <a href="http://www.comdex.com/chicago/" target="_blank">
        http://www.comdex.com/chicago/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>USENIX First International Conference on Mobile Systems, 
	Applications, and Services (MobiSys)</b><BR>
        <td valign=top>May 5-8, 2003<BR>San Francisco, CA<BR>
        <a href="http://www.usenix.org/events/" target="_blank">
        http://www.usenix.org/events/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>USENIX Annual Technical Conference</b><BR>
        <td valign=top>June 9-14, 2003<BR>San Antonio, TX<BR>
        <a href="http://www.usenix.org/events/" target="_blank">
        http://www.usenix.org/events/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>CeBIT America</b><BR>
        <td valign=top>June 18-20, 2003<BR>New York, NY<BR>
        <a href=http://www.cebit-america.com/"" target="_blank">
        http://www.cebit-america.com/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>O'Reilly Open Source Convention</b><BR>
        <td valign=top>July 7-11, 2003<BR>Location: TBD<BR>
        <a href="http://conferences.oreilly.com/" target="_blank">
        http://conferences.oreilly.com/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>12th USENIX Security Symposium</b><BR>
        <td valign=top>August 4-8, 2003<BR>Washington, DC<BR>
        <a href="http://www.usenix.org/events/" target="_blank">
        http://www.usenix.org/events/</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

<tr><td valign=top>
        <b>LinuxWorld Conference & Expo</b><BR>
        <td valign=top>August 5-7, 2003<BR>San Francisco, CA<BR>
        <a href="http://www.linuxworldexpo.com" target="_blank">
        http://www.linuxworldexpo.com</A><BR>

<tr><td colspan=2><HR size=5 width=100% noshade align=center></td></tr>

</table>
<!-- *** END events table [this line needed by Linux Gazette events.py *** -->


<a name="general"></a>
<p><hr><p>
<!-- =================================================================== -->
<center><H3><font color="green">News in General</font></H3></center>

<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">XVID and GPL
</FONT>
</H3> 
<P>
The
<a href="http://www.xvid.org/">
XVID</a> project scored a GPL win by persuading Sigma Designs to 
<a href="http://www.xvid.org/press/press-20020822-en.html">
cease infringing</a> on GPL'ed code developed by the group.
24 hours after the XVID team announced they would
cease all future development of the project, Sigma Designs 
<a href="http://biz.yahoo.com/bw/020822/220286_1.html">
relented</a>
and made their sources available.

<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">Slapper
</FONT>
</H3> 
<P>
<a href="http://slashdot.org/articles/02/09/25/1210247.shtml?tid8">
Slashdot noted the emergence</a>
of two new Linux worms, Slapper.B and Slapper.C, which exploit a buffer
overrun in OpenSSL.  If you haven't upgraded to OpenSSL 0.9.6g (or at least
e), now is a good time.  
A guy suspected of being the original Slapper
<a href="http://www.vnunet.com/News/1135274">
author has been arrested</a>.
<p>
Noel Davis at O'Reilly has recently
<a href="http://linux.oreillynet.com/pub/a/linux/2002/09/23/insecurities.html">
looked at the Linux Slapper worm and other vulnerabilities</a>.

<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">Bruce Perens
</FONT>
</H3> 
<P>
As mentioned last month,
<a href="http://perens.com/">
Bruce Perens</a>
has left <a href="http://www.hp.com/">HP</a>.  As 
<a href="http://www.theregister.co.uk/content/4/27027.html">reported by The
Register</a> this split was quite amicable, but it stemmed from Bruce's
policy of openly confronting and "baiting" Microsoft.
Taking advantage of his new freedom, Perens has launched
<a href="http://sincerechoice.com/">
the Sincere Choice initiative</a>, a reaction to Microsoft's 
<a href="http://www.softwarechoice.org/">
Software Choice</a>, which he 
<a href="http://www.theregister.co.uk/content/4/26616.html">
earlier denounced</a> as a sham.
Newsforge have an interview with Perens where he expands on the ideas
<a href="http://newsforge.com/newsforge/02/09/12/2040246.shtml?tid=19">
behind his new project</a>.


<a name="distro"></a>
<p><hr><p>
<!-- =================================================================== -->
<center><H3><font color="green">Distro News</font></H3></center>


<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">Debian
</FONT>
</H3> 
<P>

Debian Weekly News
<a href="http://www.debian.org/News/weekly/2002/34/">
reported</a>
on a
<a href="http://www.robster.org.uk/files/security-update-check.py">
Security Notification Script</a>
<a href="http://lists.debian.org/debian-devel-0208/msg01644.html">
announced</a> by
Rob Bradford.
The script compares locally installed packages with those on
<a href="http://security.debian.org/">
security.debian.org</a>, and
provides a description of the problem and the name of the Debian advisory
if the package is mentioned in the
<a href="http://www.debian.org/security/dsa.rdf">
DSA RDF file</a>.
<P>
<hr width="20%" noshade>
<P>
Those who own an X-Box, 
<a href="http://xbox-linux.sourceforge.net/articles.php?aid02248060056">
may want to try running Debian on it</a>.

<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">Linux From Scratch
</FONT>
</H3> 
<P>
The first test release of the upcoming LFS-4.0 book is uploaded and available
for download now. Head over to
<a href="http://www.linuxfromscratch.org">
http://www.linuxfromscratch.org</a>
to view and/or download it.


<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">SuSE
</FONT>
</H3> 

<P> the latest 
<a href="http://www.suse.de/en">SuSE Linux</a> version, SuSE Linux 8.1,
will be available 
by the beginning of October.


<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>, founded by Linux 
industry leaders Conectiva S.A., The SCO Group, SuSE Linux AG, and 
Turbolinux, Inc., have announced the appointment of Paula Hunter, 
an experienced technology executive and consortium leader, as its 
worldwide general manager. Hunter's appointment is effective 
immediately. The group also announced the open availability of the 
beta version of its UnitedLinux product on Sept. 23. The open beta 
source code is available for download at no charge from 
<a href="http://download.unitedlinux.com/">
download.unitedlinux.com</a>.
<P>
Unfortunately, UnitedLinux has lost some goodwill among the open-source
development community, and in particular the
<a href="http://www.fsf.org/">
Free Software Foundation</a> which published
<a href="http://lwn.net/Articles/10257/">
an open letter</a> expressing concerns about UnitedLinux's closed beta and
the manner in which it was distributed.
UnitedLinux member Connective has
<a href="http://newsforge.com/article.pl?sid=02/09/22/1526208&mode=thread&tid=17">
responded</a>
to these concerns.

<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">WinLinux
</FONT>
</H3> 
<P> 
WinLinux 2003 is a major upgrade of the 
<a href="http://www.winlinux.net/">
WinLinux</a>
system.  WinLinux is claimed to be fully compatible with Windows
95/98/Millennium.  WinLinux is also compatible with Red Hat Linux on the
Linux side offering the benefits of both systems.
WinLinux 2003 full version on CD with online support can be ordered
from
<a href="http://www.winlinux.net/2003/order/">
the website</a>.

<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">Xandros
</FONT>
</H3> 
<P>
Slashdot
<a href="http://slashdot.org/articles/02/09/18/0252255.shtml?tid2">
linked</a>
to 
<a href="http://www.osnews.com/story.php?news_id=1762">
the story on OSNews</a>
previewing beta 3b of 
<a href="http://www.xandros.com/">
Xandros Desktop</a>.  Xandros is the current custodian of what once was
<a href="http://linux.corel.com/">
Corel Linux</a>.


<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">Linux Game Publishing News Mailing List
</FONT>
</H3> 

<P> Linux Game Publishing has announced a partnership with 
<a href="http://www.pyrogon.com">Pyrogon Inc.</a>
to bring their latest games to the Linux market. This process will begin
with Candy Cruncher, a fast paced puzzle game.
Please see the 
<a href="http://www.linuxgamepublishing.com/press_releases/200209100.txt">
press release</a> for details.





<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">TinyTERM 4.3
</FONT>
</H3> 

<P>
<a href="http://www.centurysoftware.com/">
Century Software</a> has announced the release of
<a href="http://www.centurysoftware.com/products/tinyterm_plus.php?src5">
TinyTERM Version 4.3</a>.
TinyTERM lets you use your Windows PC to easily and accurately 
access character based data and applications hosted on UNIX, Linux and IBM 
servers. It includes 20 emulations, network utilities, secure 
file transfer and free technical support.
TinyTERM is 
<a href="http://www.centurysoftware.com/download/index.php?PartNum=TTPL-1&src5">
available for download</a>


<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">Kerio MailServer with integrated McAfee anti-virus program
</FONT>
</H3> 
<P>
<a href="http://www.kerio.com/us/kerio.html">
Kerio Technologies</a>
are offering a Linux based mail server product, the Kerio MailServer 5.1.6.
It has an integrated McAfee anti-virus program, and runs on Linux RedHat.
KMS offers a broad range of features and a user-friendly interface in one
package.  Kerio claim that no other comparable solution has the McAfee
Anti-Virus program integrated.




<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">IBM alphaWorks posts porting manager
</FONT>
</H3> 
<P>
<a href="http://www.ibm.com/alphaWorks">
AlphaWorks</a>
has posted a free
"porting manager" that enables the porting of C and C++ applications from
Solaris to zSeries Linux, ensuring fast deployment of applications to the
Linux platform.



<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">Ximian Offers Customized Opera for Linux with Red Carpet
</FONT>
</H3> 

<P>
<a href="http://www.opera.com">Opera</a>
has announced that its sales referral partner
<a href="http://www.ximian.com">
Ximian</a>
will include a customized version of the Opera Web browser as a download
option in its Red Carpet software management program for Linux users.
Red Carpet is a software management solution used by many Ximian
Desktop users, which keeps Linux systems up to date efficiently and
securely. The program allows users to install, update and maintain software
over the Internet from Ximian, leading Linux distribution providers, and
other independent software vendors. 

<P> <hr> <P> 
<!-- =================================================================== -->
<H3><IMG ALT=" "   SRC="../gx/bolt.gif">
<FONT COLOR="green">ActiveState Unveils Komodo 2.0
</FONT>
</H3> 
<P>
<a href="http://www.ActiveState.com">
ActiveState Corp.</a>,
has announced a new IDE that provides a powerful
workspace for cross-platform, open source language programming.
Komodo 2.0
affords greater power, flexibility and automation, including the
ActiveState GUI Builder, Visual Package Manager, Source Code Control,
Project Manager, Macros, Web services generation, and more.  The only
unified open source programming language IDE, Komodo enables editing,
debugging, and testing in a single workspace.  
<P>
Komodo is optimized for Perl, Python, PHP, Tcl, XML, XSLT, and supports
numerous other languages, including Ruby and JavaScript.



<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>

Copyright &copy; 2002, Michael Conry.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR> 
Published in Issue 83 of <i>Linux Gazette</i>, October 2002</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">Saving Users From Themselves<BR>
-or-<BR>
Dealing with User Input in Python</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/evans.html">Paul Evans</A></STRONG></BIG>

</TD></TR>
</TABLE>
<P>

<!-- END header -->




<p>You probably won't be using <a href="http://python.org/">Python</a> long
before writing a program which needs user input.  As a wide-eyed, innocent new
Python programmer, you may naively expect that you can simply ask users for
input and they will just give it to you....</p>

<BLOCKQUOTE><EM>
WARNING: Showing the preceding sentence to veteran programmers may
cause them to collapse on the floor giggling helplessly.
</EM></BLOCKQUOTE>

<p>Users don't work that way.</p>

<p>For example, if you ask for a simple 'y or n' response, your user may
cheerfully type in their name - or their lunch order, or nothing at all - and
your program will break. They don't do this on purpose (well, <i>mostly</i>). It's
just that the poor dears are easily distracted, totally ignore your carefully
worded input prompts and often type complete gibberish as far as your program
is concerned.  Next, oddly enough, they will blame you, the programmer. Then you will look
foolish and feel Unhappy.</p>

<p>To avoid this misery, the very first thing you need to do is make sure that
whatever comes back from the user is checked to see if it's even vaguely
close to what you expected. Python has heaps of functions to help you with
this and we'll begin by going through some of them together below.</p>

<p>Another thing you can do is use <i>validators</i> on your input widgets. The way
these work is they simply throw away any keystrokes that are not what you are
after. As an example, if you set a numeric validator on a string widget,
users can press 'ABC' etc. as much as they like and nothing will even show up
in the widget. The only keys they can press that will have any effect are 0-9
and, perhaps, a decimal or dollar symbol. We'll play with these too later on.</p>

<p>Finally, even if you are lucky enough to find yourself in possession of a
particularly well-trained and obedient user who always types what you ask,
the input is unlikely to be <i>formatted</i> exactly the way you want it. Careless
typing often produces strings like 'jOHN sMith' (caps lock) or phone numbers
resembling '604555-1212'.</p>

<p>All kidding aside, it's actually <i>your job</i> as a programmer to make it as
easy and fast as possible for the user to input data and that it be presented
and stored in a consistent format. Plus, you can get a great deal of personal
satisfaction and <i>even</i>, dare I say it? <i>gratitude</i> from users if you can save
them from the hell of properly typing something like a Canadian postal code.</p>

<h2>Acquiring Input</h2>

<p>First your program will need to acquire some user input. From the console
Python offers two methods for this 'raw_input("Prompt")' and 'input("Prompt")'.
(Don't use 'input', see below.) You can also get input from good ol' command
line arguments or environment variables.</p>

<p>Other, more graphical methods are available, without getting too carried away, such as
<a href="http://xdialog.free.fr">Xdialog</a>, Gdialog
(part of gnome-utils) or <a href="http://kaptain.sourceforge.net/">Kaptain</a>.</p>

<p>Access to full-blown GUI toolkits is available from Python using
<a href="http://www.riverbankcomputing.co.uk/pyqt/">PyQT</a>
, <a href="http://pmw.sourceforge.net">TKinter</a>,
<a href="http://wxpython.org">WxPython</a> and <a href="http://www.daa.com.au/~james/pygtk/">PyGTK</a>
among others.</p>

<p>This is probably a good time to provide a few words of caution. Most users
are contented, docile creatures who like to have their belly rubbed, but you
<i>will</i> encounter rogue types bent on destruction.</p>

<p>For this reason you must never allow user input to leak into your command space:</p>

<ul>
  <li><STRONG>Use 'raw_input()' instead of 'input()'.</STRONG>  'input()' is
  fed to 'eval()' before your program gets it.  This automatically converts
  types, which is convenient if you want an integer <EM>and</EM> the user accidentally
  gives you one.  But the user would have to quote strings.  Worse, a rogue user
  might type 'os.system("rm -r *")', which would give you a bad day.
  'raw_input()' returns whatever the user entered as a string.  This makes
  validation easier, because you know what type it will be and thus which
  operations you can apply to it.<p></li>
  <li><STRONG>Always check input to os.system(), os.popen() or os.exec*() calls.</STRONG>
<p></li>
  <li><STRONG>Always escape user input before printing it to a web page or using it in a
SQL query.</STRONG>  This is in addition to input checking.  Unescaped special
characters can cause invalid HTML, screw up your page formatting, and allow the user
to exploit Javascript "features" against another user.  Unescaped special characters in
a SQL query may cause a SQL syntax error or cause the query to do more
than intended.  Use 'cgi.escape()' to escape HTML.  See your database documentation
to escape SQL queries.
<p></li>
</ul>


<p>O.K. Relax. The spooky part is over.</p>

<p>Open an xterm and type 'python' to enter the interpreter. Note: Many of these
examples <i>require</i> that you be using a version of Python greater than or
equal to version '2'. Redhat still ships with version 1.5x as
default, so if you are a Redhat user you will need to type 'python2' instead
(and possibly install the rpm first from 'add-ons'). For the record, version
'1.5' was released in a year which began with the digits '1' and '9'.</p>

<h2>Checking the Content of String Objects</h2>

<p>Programming languages usually include methods for checking of this kind and
Python is no exception. Consider one of our first challenges as stated above:
making sure the user gives us a valid number when we ask for one.</p>

<p>It happens that all string objects in Python have built-in <i>methods</i>  which
make this quite painless. Type these lines in at the '&gt;&gt;&gt;' prompt:</p>

<pre>
&gt;&gt;&gt;input = '9'
&gt;&gt;&gt;input.isdigit()
1
</pre>

<p>This will return a '1' (true), so you can easily use it in an 'if' statement
as a condition. Some other handy attributes of this kind are:</p>

<pre>
s.isalnum() returns true if all characters in s are alphanumeric, false otherwise.
s.isalpha() returns true if all characters in s are alphabetic, false otherwise.
</pre>

<p>For a complete list of these and much more, I highly recommend the
<a href="http://www.brunningonline.net/simon/python/PQR2.1.html">Python 2.1 Quick Reference</a>. I use this all the time and even have an
older text version stuffed into <a href="http://hnb.sourceforge.net">HNB</a> for speed.</p>

<p>This will get us through simple cases like menu choices, but what if we
wanted a float or a real number?</p>

<p>Consider:</p>

<pre>
input = '9.9' or
input = '-9'
</pre>

<p>Both of these are valid numbers, but input.isdigit() will return '0' (false),
because the negative sign and the decimal point are not 'digits'. Our
poor user will be very confused when we spit back an error message if these
entries are valid.</p>

<p>So, let's <i>assume</i> that they are what we want and try to convert
them explicitly. For this we'll use the Python <i>try/except</i> construction.
Python raises <i>exceptions</i> of different kinds on errors and we can trap these
errors individually by name.</p>

<p>Say we wanted an integer like '-9', we can use the numeric operator 'int()'
to explicitly attempt the conversion for us.</p>

<pre>
try:
    someVar = int(input)
    print 'Is an integer'
except (TypeError, ValueError):
    print 'Not an integer'
</pre>

<p>Two things to notice here. The first is that we are checking for two
different exceptions, Type and Value. This way we not only handle the user
entering a float (like '9.9'), but we also allow for the possibility that they
didn't even enter a number of any kind - perhaps they entered 'Ham on rye'.
The second thing to notice is that <i>we actually entered the kinds of
exceptions we were interested in trapping.</i> It's very easy to just type in
open ended exceptions without bothering to look up which errors you are
trapping like this:</p>

<pre>
try:
    someVar = int(input)
    print 'Is an integer'
except:
    print 'Not an integer'
</pre>

<p>DO NOT DO THIS. Python will let you, but since you are now trapping <i>all</i>
exceptions debugging will be a nightmare for you if anything breaks. Just
trust me on this one; look up the errors you mean to trap and you'll save
time in the long run.</p>

<p>Other operators you'll find useful are long() and float(). On the flip side,
str() can convert anything to a string.</p>

<p>Don't forget to range check - it's no good congratulating yourself on
ensuring your program always gets an integer from a user if it blithely
accepts the integer '42' as a valid month day... Make sure the number falls
into the expected range using the comparison operators '&gt;, &lt;, &gt;=' etc.</p>

<h2>Validating Input</h2>

<p>As we've seen, we can validate input <i>after</i> we get it, but wouldn't it be
nice if we could prevent the user from entering mistakes in the first place?</p>

<p>Enter widget validators.</p>

<p>These are things built into graphical user interface toolkits that prevent
unwanted keystrokes from even <i>appearing</i> in the string widget. Toolkits usually
come with some built-in validators for numeric, alpha, and alphanumeric etc.
and are quite easy to use. I'm currently using mostly <a href="http://www.riverbankcomputing.co.uk/pyqt/">PyQT</a>
 for gui's, but <a href="http://pmw.sourceforge.net">TKinter</a>,
<a href="http://wxpython.org">WxPython</a> and even <a href="http://kaptain.sourceforge.net/">Kaptain</a>
all have validators. I could be wrong, but <a href="http://www.daa.com.au/~james/pygtk/">PyGTK</a>
seems not to have them - yet. Perhaps you could hook up a signal and roll your own if you happen to
use a toolkit that doesn't have them.</p>

<p>If the built-in validators don't suit you then PyQt, for example, allows you
to specify your own, custom validators.</p>

<p>Clearly, I can't go into detail for every toolkit out there, but here's an
example of how to attach a numeric validator to a widget in PyQT. The
widget's name is 'self.rate', we're attaching the 'QDoubleValidator' and
telling it to accept numbers between 0.0 and 999.0 up to 2 decimal places:</p>

<pre>
self.rate.setValidator(QDoubleValidator(0.0, 999.0, 2, self.rate) )
</pre>

<p>Nice eh? Notice it took care of range checking for us too!</p>

<p>Other ways to help users enter information include spinners, pick-lists and
combo-boxes, but you already knew that.</p>

<h2>Formatting Input</h2>

<p>Remember the 'jOHN sMith' example from the introduction? Here's the fix:</p>

<pre>
&gt;&gt;&gt;'jOHN sMith'.title()
'John Smith'
</pre>

<p>Yes, yet another attribute of all string objects in Python is the 'title()'
attribute which will helpfully capitalize each word for you. 'capitalize()'
is similar, but only does the first character:</p>

<pre>
&gt;&gt;&gt; 'jOHN sMith'.capitalize()
'John smith'
</pre>

<p>Go ahead and try 'upper()', 'lower()' and 'swapcase()' on your own if you
like. I think you can guess their behaviour.</p>

<p>But how about 'rjust(n)'? This is only one of some really handy attributes
you can use to layout reports. Watch:</p>

<pre>
&gt;&gt;&gt; 'John Smith'.rjust(15)
'     John Smith'
</pre>

<p>Our string has been right justified for us in a string 15 characters long.
Sweet. As you've probably guessed, there are also 'center(n)' and 'ljust(n)'.
Again, have a look at the
<a href="http://www.brunningonline.net/simon/python/PQR2.1.html">Python 2.1 Quick Reference</a>
to see them all.</p>

<p>Another, very important operator in Python is the '%' (per cent) operator.
The description of this in combination with list objects and printf-style
formatting codes could easily consume several pages, so I'm just going to gloss
over it with a few examples to pique your interest today.</p>

<p>In it's simplest form, the '%' operator lets you write, say, a proper sentence that includes variables which can change
at runtime:</p>

<pre>
&gt;&gt;&gt; 'This is a %s example of its %s.' % ('good', 'use')
'This is a good example of its use.'
</pre>

<p>At least, I hope it is. This is only the beginning of its power. In addition to just string object substitution with
'%s' there is also '%r' and the printf friends from the 'C' language:
c, d, i, u, o, x, X, e, E, f, g, G.</p>

<p>Here's an example from <a href="http://www.brunningonline.net/simon/python/PQR2.1.html">Python 2.1 Quick Reference</a>:</p>

<pre>
&gt;&gt;&gt; '%s has %03d quote types.' % ('Python', 2)
'Python has 002 quote types.'
</pre>

<p>The right hand side may also be a mapping, which allows you to refer to fields by name.
</p>

<p>Let's move on to something a little more challenging, but common enough.</p>

<h3>Phone Numbers</h3>

<p>Phone numbers are variable in length. Sometimes they are only 2 or 3 digits
long if you are behind a corporate PBX system. Other times they might stretch
out to 15 digits or more for international calling. They <i>might</i> even contain
'#' symbols or asterisks. Maybe even commas. Worse, the user may attempt to
impose a format on it as they enter it. Or a partial format. Or not.</p>

<p>Now, it will only frustrate your user if you don't let them at least try to
enter it properly, so your validator had better accept all of #, *, 'comma',
-, ), ( as well as the digits 0-9. Of course, you could still end up with:</p>

<pre>
'250-(555)-12-12'
</pre>

<p>instead of the string:</p>

<pre>
'(250) 555-1212'
</pre>

<p>that we actually want (for a North American phone number anyhow). Don't
worry, we'll make the solution generic enough to handle just about anything.</p>

<p>My first instinct when I need something like this is to copy someone else's
work by mining <a href="http://www.google.com">Google</a> - especially <a href="http://www.google.com">Google Groups</a>. This turns out to
be a good instinct for me to have since the code snippet I usually find will
be far better than I could do on my own. Unfortunately, this time I turned up
an email from Guido van Rossum (the inventor of Python) explaining to someone
that Python did not have such a thing and perhaps they could use something
like:</p>

<pre>
import string
def fmtstr(fmt, str):
    res = [] i = 0
    for c in fmt:
        if c == '#':
            res.append(str[i:i+1]) i = i+1
        else:
            res.append(c)
    res.append(str[i:])
    return string.join(res)
</pre>

<p>This is a darn good start of course and you can't argue with the credentials of
its author, but it doesn't handle all the cases without a lot of 'if/then'
constructs to count how many digits you were given in order to choose a format
string of the correct length. Go ahead and paste it
into your xterm and then call it like this:</p>

<pre>
&gt;&gt;&gt; fmtstr('###-####', '5551212')
'5 5 5 - 1 2 1 2 '
</pre>

<p>In fact, I did copy and paste it into my editor and then constructed a long sequence of
'if/thens' for phone numbers, dates and other types of entries, but I still wasn't
handling everything. Plus, I had dozens and dozens of lines doing self-similar
things. They have since passed on to their reward.</p>

<p>O.K., here we go... First, let's filter any "extra" formatting characters we
let the user type in:</p>

<pre>
def filter(inStr, allowed):
    outStr = ''
    for c in inStr:
        if c in allowed:
            outStr += c
    return outStr
</pre>

<p>We could call it like this:</p>

<pre>
&gt;&gt;&gt;filter('250-(555)-12-12', string.digits)
'2505551212'
</pre>

<p>Or we could define the second argument ourselves as '0123456789#*,' to
include all the allowable characters possible.</p>

<p>Now we just take Guido's code snippet and (this is the good bit) <i>reverse</i>
both the input arguments. This way we can specify just one long format string
and it will be matched until we run out of input. Any extra input will just
get tacked on, so we will never lose any characters.</p>

<pre>
# import the regular expression module
import re

def formatStr(inStr, fmtStr, p = '^'):
    inList = [x for x in inStr] #list from strings..
    fmtList = [x for x in fmtStr]
    # the good bit
    inList.reverse(); fmtList.reverse()
    outList = []
    i = 0
    for c in fmtList:
        if c == p:
            try:
                outList.append(inList[i])
                i += 1
            # break if fmtStr longer than inStr
            except IndexError:
                break
        else:
            outList.append(c)
    # handle inStr longer than fmtStr
    while i &lt; len(inList):
        outList.append(inList[i])
        i += 1
    # put it back the way we found it
    outList.reverse()
    outStr = ''.join(outList)
    # remove stray parens/- etc
    while re.match('[)|-| ]', outStr[0]):
        outStr = outStr[1:]
    # close any legit parens
    while outStr.count(')') &gt; outStr.count('('):
        outStr = '(' + outStr
    return outStr
</pre>

<p><a href="misc/evans/fmtstr.py.txt">[Text version of this listing.]</a></p>

<p>It's basically the same as Guido's except the default placeholder character is now
a '^' (caret), because we may need to use the '#'. Alternatively, this may be
specified as an, optional, third argument if we ever need real carets in the output.</p>

<p>Here's some sample output:</p>

<pre>
&gt;&gt;&gt; formatStr('51212', ' ^^^ ^^ (^^^) ^^^-^^^^')
'5-1212'
&gt;&gt;&gt; formatStr('045551212', ' ^^^ ^^ (^^^) ^^^-^^^^')
'(04) 555-1212'
&gt;&gt;&gt; formatStr('16045551212', ' ^^^ ^^ (^^^) ^^^-^^^^')
'1 (604) 555-1212'
&gt;&gt;&gt; formatStr('1011446045551212', ' ^^^ ^^ (^^^) ^^^-^^^^')
'1 011 44 (604) 555-1212'
</pre>

<p>In practice, you'll probably want to simply define your phone formatting
string early on e.g.:</p>

<pre>
phone_format_str = ' ^^^ ^^ (^^^) ^^^-^^^^'
</pre>

<p>There's a space at the beginning of the string so that any additional characters won't get smooshed onto it. You'd likely call it thus:</p>

<pre>
formatStr(input, phone_format_str)
</pre>

<p>... after you clean up your 'input' with something like the 'filter()' function.</p>

<h3>Postal Codes</h3>

<p>In case you are (blessedly) unfamiliar with Canadian postal codes, they look like
this:</p>

<pre>
'V8G 4L2'
</pre>

<p>Which <i>appears</i> innocuous enough until you attempt to type it. Especially
for non-typists (like me). You can turn on the caps lock - and then forget
to turn it off - or you have to type [shift]+alpha, number, [shift]+alpha
etc. and quite often end up with: 'v*g $l@' when you get out of sequence.
Needless to say, users <i>hate</i> typing them in and they hardly ever
look right. Mostly your application won't even capture postal codes, because
users simply won't bother. Some other countries have similar post codes. Shame.</p>

<p>Now, with our new formatting function, they're a piece of cake. First, we either
validate or filter whatever they give us, then we simply use Python's
built-in string attribute 'upper()' to set the case of the alpha characters
properly, finally:</p>

<pre>
&gt;&gt;&gt;formatStr('V8G4L2', ' ^^^ ^^^')
'V8G 4L2'
</pre>

<p>If accurate postal codes are critical to your application, you will need to do
more verification by way of counting the characters and verifying the pattern. For
general use though, you need to allow for the postal codes of other countries. I
think I normally format only if the number of characters == 6 after clean up.</p>

<p>How about Social Insurance Numbers? Same deal:</p>
<pre>
&gt;&gt;&gt; formatStr('716555123', '^^^-^^^-^^^')
'716-555-123'
</pre>

<p>You should run a check digit routine over Social Insurance Numbers first to
ensure they are valid. Ditto for credit cards.</p>

<p>I hope these examples will save you some time in coding user interfaces. I'd
very much like to <a href="mailto:pevans@catholic.org?subject=LG article on User Input">hear back</a>
with examples or improvements of your own. Particularly ways of dealing with dates<SUP><A HREF="#foot1">1</A></SUP> with users. They're always fun.</p>

<p>By the way, it's very important that you not keep these formatting aids a secret from your users. Put it in the 'help', use
'tooltips' or 'whatis' to let them know the facility is there for them. If they find out after months of typing things the long way,
they are liable to pout and you'll end up wasting afternoon coffee scratching them behind the ears (morning coffee is a given).</p>

<p>Have fun with it!</p>

<A name="foot1">1</A> That's <i>calendar</i> dates...





<!-- *** BEGIN bio *** -->
<SPACER TYPE="vertical" SIZE="30">
<P>
<H4><IMG ALIGN=BOTTOM ALT="" SRC="../gx/note.gif">Paul Evans</H4>
<EM>Paul Evans loves everything about electronics and computers in particular. He
is old enough to remember drooling over an Altair 8080A in his adolescence.
He and his two children live in the Wilds of Northern British Columbia;
they're not lumberjacks, but they're OK.</EM>


<!-- *** END bio *** -->

<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>

Copyright &copy; 2002, Paul Evans.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR> 
Published in Issue 82 of <i>Linux Gazette</i>, September 2002</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">Creating Makefiles: A Mini Tutorial</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/heriyanto.html">Tedi Heriyanto</A></STRONG></BIG>

</TD></TR>
</TABLE>
<P>

<!-- END header -->





<DIV>
This article will provide a guidance to create your own Makefile. The article will 
explain why we need a Makefile and will also list several things we
should consider in creating a Makefile. 
</DIV>
<P>

<P>

<H1><A NAME="SECTION00010000000000000000">
Introduction</A>
</H1>

<P>
Imagine you are developing a program called <TT>foo</TT>, which consists
of five headers, that is <TT>1.h</TT>, <TT>2.h</TT>, <TT>3.h</TT>,
<TT>4.h</TT>, and <TT>5.h</TT>, six C-language source code files
named <TT>1.cpp</TT> to <TT>5.cpp</TT>, and a <TT>main.cpp</TT> file
(Remember: we do not recommend to use such file naming scheme in the real
life).

<P>
Suppose you find a bug in <TT>2.cpp</TT> and has fix it.
In order to get a new <TT>foo</TT> program, you have to recompile
all files, header and source code, even though you just change one
file. This is not a fun job, waiting for the computer to finished its
process compiling your program. Particularly if you don't have fast computer.

<P>
What can you do then? Is there any solution for this problem ?

<P>
Please do not worry my friends. That kind of problem has already been
experienced by our fellow computer hackers years ago. To tackle this
problem, they have developed a program called <TT>make</TT>. Instead
of build all of the source codes, this program will only build
source code that has been changed. If you change file <TT>2.cpp</TT>, then <TT>make</TT>
will only build it. Isn't it fun?

<P>
The followings are several other reasons why we need <TT>make</TT> [<A
 HREF="#lpu">2</A>] :

<UL>
<LI>A software project which consists of many source codes, can have
complex and long compiler commands. Using <TT>make</TT>, it can be reduced.
</LI>
<LI>Programming project sometimes need specialized compiler options
that are so rarely used they are hard to remember; with <TT>make</TT>
this can be reduced.
</LI>
<LI>Maintaining a consistent development environment.
</LI>
<LI>Automating the build process, because <TT>make</TT> can be
called easily from a shell script or a cron job.
</LI>
</UL>

<P>

<H1><A NAME="SECTION00020000000000000000">
Why Do We Need a Makefile?</A>
</H1>

<P>
Although <TT>make</TT> is very useful, it cannot do its job
without the instructions given by us, the programmer. <TT>make</TT>
instructions is stored in a text file. This file is usually called
<B>makefile</B> and contains commands that must be processed by
<TT>make</TT>.

<P>
This file is normally named <TT>makefile</TT> or <TT>Makefile</TT>. As a
convention, GNU programs named their makefile, <TT>Makefile</TT>, because
it is easy to see (if you do "ls" then this file is usually always on
the top of the list). If you give it another name, just make
sure you include option <TT>-f</TT> to <TT>make</TT> command in order
to let it know that you use it.

<P>
For example, if we have a makefile named <TT>bejo</TT>, then the
command we use to instruct <TT>make</TT> to process that file is :

<PRE>
make -f bejo
</PRE>

<P>

<H1><A NAME="SECTION00030000000000000000">
Makefile Structure</A>
</H1>

<P>
A makefile consists of <I>target</I>, <I>dependencies</I> and <I>rules</I>
section. Dependecies are things or source code needed to make a target;
target is usually an executable or object file name. Rules are commands needed to make
the target. 

<P>
Following is a simple description of a makefile :
<PRE>
target: dependencies
	command
	command
	...
</PRE>

<P>

<H1><A NAME="SECTION00040000000000000000">
An Example of Makefile</A>
</H1>

<P>
The following is a simple makefile example (line numbers added for the article):

<P>
<PRE>
1 client: conn.o 
2	g++ client.cpp conn.o -o client
 
3 conn.o: conn.cpp conn.h
4   g++ -c conn.cpp -o conn.o
</PRE>

<P>
In the makefile above, dependencies is line contained <TT>client:
conn.o</TT>, while rules is line contained <TT>g++ client.cpp conn.o -o
client</TT>.  Note that <EM>every rule line begins with a tab, not
spaces</EM>. Forgetting to insert a tab at the beginning
of the rule line is the most common mistakes in constructing
makefiles. Fortunately, this kind of error is very easy to be
spotted, because  <TT>make</TT> program will complain about it.

<P>
Detail description of the makefile depicted above are as follows :

<UL>
<LI>Create an executable file named <TT>client</TT> as a target, which
depends on file <TT>conn.o</TT>
</LI>
<LI>Rules to create the target are in line 2.
</LI>
<LI>In the third line, to make target <TT>conn.o</TT>, <TT>make</TT>
needs files <TT>conn.cpp</TT> and <TT>conn.h</TT>.
</LI>
<LI>The rules to make target <TT>conn.o</TT> are in line 4.
</LI>
</UL>

<P>

<H1><A NAME="SECTION00050000000000000000">
Comment</A>
</H1>

<P>
To give a comment in makefile, merely put '#' in the first column of each line
to be commented.

<P>
Below is an example makefile that has already been commented :

<P>
<PRE>
# Create executable file "client"
1 client: conn.o
2   g++ client.cpp conn.o -o client

# Create object file "conn.o"
3 conn.o: conn.cpp conn.h
4   g++ -c conn.cpp -o conn.o
</PRE>

<P>

<H1><A NAME="SECTION00060000000000000000">
Phony Target[<A
 HREF="#gnum">1</A>]</A>
</H1>

<P>
A phony target is a fake filename. It is just a name for commands that
will be executed when you give an explicit request. There are two reasons
for using phony target : to avoid conflicts with a file with the same
name, and to enhance the makefile performance.

<P>
If you write a rule whose command will not create a target file,
those commands will be executed every time the target is remade. For example:

<P>
<PRE>
clean:
	rm *.o temp
</PRE>

<P>
Because the command <TT>rm</TT> will not create a file named <TT>clean</TT>,
that file will never exist. Command <TT>rm</TT> will always be executed
every time you called <TT>make clean</TT>, because <TT>make</TT>
assume that the <TT>clean</TT> file is always new.

<P>
The above target will stop working if a file named
<TT>clean</TT>  exists in the current directory. Because it does not require
dependencies, file <TT>clean</TT> will be considered up-to-date, and the
command 'rm *.o temp' will not be executed. To resolve this problem, you can explicitly
declare a target as phony, using special target command <TT>.PHONY</TT>. For example :

<P>
<PRE>
.PHONY : clean
</PRE>

<P>
In the makefile above, if we give instruction <TT>make clean</TT> from
the command-line, the command 'rm *.o temp' will always be run,
whether or not a file named <TT>clean</TT> exists in the current
directory.

<P>

<H1><A NAME="SECTION00070000000000000000">
Variable</A>
</H1>
To define a variable in a makefile, you can use the following command:
<PRE>
$VAR_NAME=value
</PRE>

<P>
As a convention, a variable name is given in uppercase, for example :
<PRE>
$OBJECTS=main.o test.o
</PRE>

<P>
To get a varible's value, put the symbol $ before the variable's
name, such as :
<PRE>
$(VAR_NAME)
</PRE>

<P>
In makefile, there are two kinds of variables, <I>recursively
	expanded variable</I> and <I>simply expanded variable</I>. 

<P>
In the recursively expanded variable, <TT>make</TT> will continue expanding
that variable until it cannot be expanded anymore, for example :
<PRE>
TOPDIR=/home/tedi/project
SRCDIR=$(TOPDIR)/src
</PRE>

<P>
SRCDIR variable will be expanded, first by expanding TOPDIR variable.
The final result is <TT>/home/tedi/project/src</TT>

<P>
But, recursively expanded variable will not be suitable for the
following command :
<PRE>
CC = gcc -o
CC = $(CC) -O2
</PRE>

<P>
Using a recursively expanded variable, those command will go to endless
loop. To overcome this problem, we use a simply expanded variable :
<PRE>
CC := gcc -o
CC += $(CC) -O2
</PRE>

The ':=' symbol creates the variable CC and given its value "gcc -o".
The '+=' symbol appends "-O2" to CC's value.

<P>

<H1><A NAME="SECTION00080000000000000000">
Closing Remarks</A>
</H1>

<P>
I hope this short tutorial will give you enough knowledge to create
makefile. Until then, happy hacking.

<P>
 
<H2><A NAME="SECTION00090000000000000000">
Bibliography</A>
</H2>

<ul>
	<li><A NAME="gnum"><SUP>1</SUP></A>
 GNU Make Documentation File, info make.
 <li><A NAME="lpu"><SUP>2</SUP></A>
Kurt Wall, et.al., <I>Linux Programming Unleashed</I>, 2001.
</ul>
</DL>




<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>

Copyright &copy; 2002, Tedi Heriyanto.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR> 
Published in Issue 83 of <i>Linux Gazette</i>, October 2002</H5>
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
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<IMG ALT="LINUX GAZETTE" SRC="../gx/2002/lglogo_200x41.png" 
	WIDTH="200" HEIGHT="41" border="0"></A> 
<BR CLEAR="all">
<SMALL>...<I>making Linux just a little more fun!</I></SMALL>
</TD><TD WIDTH="380">


<center>
<BIG><BIG><STRONG><FONT COLOR="maroon">Multi-Account E-mail with Mutt</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/klimkiewicz.html">Kamil Klimkiewicz</A></STRONG></BIG>

</TD></TR>
</TABLE>
<P>

<!-- END header -->




<p>About three or four months ago I switched from Windows to Linux. I had
been using Linux before but it was only my second operating
system. When it became my primary one I had to deal with several
problems. Most of them I was able to fix quickly. There was one thing
which caused many troubles - I had three e-mail accounts.</p>

<p>Windows user could say, "Download some e-mail client and configure it
to use several accounts." But there is something called the 'Unix
philosophy'. It says that programmers should write small applications
which do only one thing but do it well. What does it mean for us? It
means that there is no single tool which fetches your mail from
remote server, allows you to read and write mail and sends it to its
target.</p>

<p>In this short article I will only show you how to configure tools
called <em>fetchmail</em> and <em>mutt</em>. If you
want to go deeper into this topic you should read:</p>
<ul>
<li>Mail-Administrator-HOWTO,</li>
<li>Mail-User-HOWTO.</li>
</ul>

<p>You can get them from <a
href="http://www.linuxdoc.org">http://www.linuxdoc.org</a>.</p>

<h2>1. Environment</h2>
<p>Let's define our e-mail environment: we have three e-mail accounts,
each placed on different server. We will call them 'First', 'Second'
and 'Third.' Their addresses are: first@firstdomain.com,
second@seconddomain.com, third@thirddomain.com. Moreover the first
account uses IMAP protocol and the others POP3.</p>

<p>The local user who is going to receive all the messages is called
'john'. We need to set new value for $MAIL environment variable, since
we won't use default '/var/spool/mail/john' (this is unsafe and less
convenient.) To do this we add following lines to .bash_profile (of
course if you use different shell you have to change different
things):</p>
<pre>
MAIL=$HOME/Mail/Inbox
export MAIL
</pre>

<p>(Don't forget to create directory '$HOME/Mail'!.)
We will also use additional mailboxes for read messages (each account
has its associated box.)</p>

<h2>2. Fetchmail</h2>
<p>Before we can read our mail we have to fetch it from remote server. To
do this we will use a tool called <b>fetchmail</b>. It should be
already installed on your system.</p>

<p>Configuring fetchmail is quite easy task. Moreover we can use utility
'fetchmailconf' which makes the process even easier.
Configuration file we should edit is <em>$HOME/.fetchmailrc</em>. Simple one,
appropriate for our environment, looks like this:</p>
<pre>
set postmaster "john"
set bouncemail
set properties ""
set daemon 300
poll First via firstdomain.com
 with proto IMAP
       user first there with password this_is_password is john here warnings 3600

poll Second via seconddomain.com
 with proto POP3
       user second there with password this_is_password is john here warnings 3600

poll Second via thirddomain.com
 with proto POP3
       user third there with password this_is_password is john here warnings 3600
</pre>

<p>To run fetchmail you only need to type <em>fetchmail</em>. It will be
started in daemon mode and will check whether there is new mail every
5 minutes.</p>

<h2>3. Mutt</h2>
<p>Our messages are on local machine now, so we can read them using
any Mail User Agent. I assume it is <em>mutt</em> because this article
is intended to deal with mutt.</p>

<p>Mutt needs to be configured before it can work like we want. First
of all we have to put some basic definitions in its configuration file
(it is usually called <em>$HOME/.muttrc</em>.) They can look like
this:</p>
<pre>
set mbox = "~/Mail/Inbox"
set move = no
set folder = "~/Mail"
set record = +Sent
mailboxes +Inbox +First +Second +Third
</pre>

<p>This actually allows us to read the messages but every outgoing
message will have something like <em>john@localhost</em> in its
<em>From</em> header field. We should be able to change the sender
address so the message can look like it was sent from
<em>firstdomain.com</em> or <em>seconddomain.com</em> or whatever
machine you have account on.</p>

<p>To achieve this we use additional mailboxes (First, Second and
Third) and mutt's so called <em>hooks</em> mechanism. The latter
executes user defined commands when some action is being
performed. There is <em>folder-hook</em> which is called when user
changes mail folder (by pressing 'c' key.) To change the <em>From</em>
field we need to modify <em>from</em> and <em>realname</em> mutt
variables:</p>
<pre>
# Default action:
folder-hook . set from = first@firstdomain.com
folder-hook . set realname = First
# First account:
folder-hook First set from = first@firstdomain.com
folder-hook First set realname = First
# Second account:
folder-hook Second set from = second@seconddomain.com
folder-hook Second set realname = Second
# Third account:
folder-hook Third set from = third@thirddomain.com
folder-hook Third set realname = Third
</pre>

<p>We should also define the <em>alternates</em> variable so mutt can
recognize messages sent to and by us:</p>
<pre>
set alternates = "first@firstdomain\.com|second@seconddomain\.com|third@thirddomain\.com"
</pre>

<p><b>Note:</b> There is a web tool called <em>MuttrcBuilder</em> at
<a href="http://mutt.netliberte.org">http://mutt.netliberte.org</a>
which you can use to configure your mutt.</p>




<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>

Copyright &copy; 2002, Kamil Klimkiewicz.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR> 
Published in Issue 83 of <i>Linux Gazette</i>, October 2002</H5>
</STRONG></SMALL></CENTER>
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</TD><TD WIDTH="380">


<center>
<BIG><BIG><STRONG><FONT COLOR="maroon">Replicating a Linux System - Yet Another Method</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/okopnik.html">Ben Okopnik</A></STRONG></BIG>

</TD></TR>
</TABLE>
<P>

<!-- END header -->




<h3>
Why Replicate?</h3>
Replication - sometimes referred to as cloning - is the process of copying
an installed filesystem from one machine to another (usually to a new machine)
instead of going though the entire installation process again; a good thing
indeed. Given the speed at which computers improve, by the time you have
your system tweaked and tuned exactly the way you like it - usually at
the cost of dozens if not hundreds of hours of playing with it - the hardware
is outdated. Replication allows you to conserve all that effort by simply
transferring the entire configured system to new hardware.
<p>What makes replication a uniquely wonderful experience under Linux is
the large number of options for doing so, which implies flexibility and
the ability to adapt the method to your exact situation - just as I have
here. Other OSes are generally confined to one rather restrictive method
(in effect, "dd"ing the hard drive contents to an identical drive.) With
Linux, you can pick whatever method suits your needs. However, there is
a cost - the same one that applies to just about anything else in Linux.
As the XFree folks say, "don't set policy - provide a mechanism." What
you have to do, rather than blindly running a provided menu-driven application
(what
<b>is</b> that thing doing behind the scenes? Can you troubleshoot
the process if it goes wrong?) is a) understand the process, and b) choose
the tools that will make it happen. In the world of Unix, where "small
sharp tools" is a major tenet of the underlying philosophy, this is the
default way to work.
<h3>
A Little Insanity Goes A Long Way</h3>
Before you read any further, <STRONG>A WARNING:</STRONG>

<BLOCKQUOTE><EM>
This is <b>not</b>
the standard way to replicate a Linux system. What is described below was
an experiment just to see if it could
be done. Yes, you could probably repeat my results - you might even find
it as convenient as I did to do it this way - but if you
mess it up and end up causing clogged toilets in New Guinea, earthquakes
in Abu Dhabi, and war between Earth and the
intelligent cephalopods of Beta Cygni 4, don't blame me!
</EM></BLOCKQUOTE>

It seems that for a number of people, myself most emphatically included,
the best way to learn how something works is to take it apart and then
put it back together (usually turning a five-dollar toy into a three-day-long
project and seven gallons of sweat, but - oh well.) So... about a week
ago, I was given a computer, somebody's "outdated" box. (Wind*ws is great.
No, really. There's no way I'd run it, but I love the effect it has: it
makes people think that a P3-400/64MB machine is "outdated". There are
always going to be a lot of uninformed folks out there, so I can see a
lifetime of free computers ahead of me! Somebody else here wants to give
me a really nice 486 Gateway laptop, too...)
<p>Of course, as far as I'm concerned, new computer = Linux installation.
That's like ham and eggs, bread and butter, <i>agua caliente para chocolate</i>
(yes, I'm getting a little hungry here, but you get the idea.) It's just
natural. However, my install CDs are old enough that I have to wipe off
the Tyrannosaurus footprints - I mean, they're almost a year old! - so
I wasn't going to do that. Hmm. My Net access these days consists of walking
over to the marina office (I live on a sailboat) and plugging into a phone
jack - dragging over a desktop PC and leaving it plugged in for a week
wasn't going to be looked on favorably. Scrap <i>that</i> scenario. I could
order the latest CD set from <a href="http://www.cheapbytes.com">CheapBytes.com</a>,
but I didn't feel like waiting for several days: I had a time slot <i>now.</i>
This was going to take a little planning.
<p>My laptop has a well-polished install of Debian on it - I've had quite
a while to get it all set up exactly the way I want it. I could just "dd"
everything over, and - oh. The laptop drive is 12GB; the drive I dug up
was an old 6GB that had a 2GB partition with some historical data on it
and a
<i>really</i> ancient Debian install. I didn't want to just scrap
the data, didn't feel like messing around with my backups and tape drives,
and 12 won't fit into 6 anyway. Let's see. A fair chunk of that 12 is my
music collection; heck, I'll just leave it on the 'top. Next, there's my
"Data Dump": an FTP archive backup, a mirror of the Comprehensive Perl
Archive Network (CPAN)... yeah, all that could stay there too. A little
decision-making, and my entire kit of programs turned out to fit into about
2GB - just what the doctor ordered! All except one thing, that is - how
would I get it from <b>here</b> to <b>there</b>, keeping all the permissions,
etc. correct? And what other problems would I run into?
<p>There are a number of standard methods for installing Linux: CD or other
media, an archive or a loop-mounted image via a network, raw copying between
same-sized drives with "dd", and - closest to what I wanted - a filesystem
dump between identically laid-out systems (see Jim Dennis' tip in LG#68,
"Bulk File Transfers from Wind*ws to ???".) However, I wasn't doing any
of those, not even the last; instead, I was going to transfer bits and
pieces to a different FS layout. Would it work? In a move strongly fueled
by way too much machismo, entirely too little sense, and Mike Orr's column
in this very magazine (see his "The Foolish Things We Do With Our Computers"
[look in the <A HREF="../lg_index.html">Index of All Issues</A> to find it]
-- perhaps this whole article belongs in that category!), I said to myself:
"Self... let's do it anyway. We can
<i>always</i> restart from scratch."
<h3>
Diving Head-First Into The Dark Waters</h3>
One of my main tools for this project was the Bootable Business Card from
the <a href="http://www.lnx-bbc.org">LNX-BBC project</a>. I booted the
new machine with it and used "mke2fs" with the "-j" option (this creates
a journal on the new partition, something I needed since I use ext3 on
my laptop) to reinitialize "/dev/hda2" - this is where Linux would live.
Next, I mounted "/dev/hda2" on "/mnt/0", activated the network card by
entering "insmod dmfe" (the new desktop came with an on-board Davicom),
assigned it an IP address ("ifconfig eth0 192.168.0.5"), and I could now
"see" the laptop - which was ready and waiting at 192.168.0.3, courtesy
of a NetGear PCMCIA card and a crossover cable.
<p>I don't run any network services on my laptop by default - one of the
first things I do in almost any install is disable "inetd" - but here,
I wanted to use "sshd" for a specific reason. Therefore, Baldur (the laptop)
got a command of "su -c '/etc/init.d/ssh start'", and Ymir (the desktop)
got "rsync -e ssh -avz --exclude-from file.lst root@192.168.0.3:/ /". The
exclude list, a file called "file.lst" (files and directories that "rsync"
should ignore) was a fairly short one: "/proc/", not being a "real" filesystem,
didn't need to be copied (in fact, doing so would be a bad idea); however,
I did make an empty "/proc" directory on the new partition. I skipped "/lost+found/"
as well - one was automatically created on Ymir when I ran "mke2fs" (besides,
it's not just a simple directory; see "mklost+found" for more info). I
also most carefully did not copy the journal-related files ("/.journal"
and "/.memdump") from Baldur; they would have no relation to the disk state
on Ymir, and could probably screw things up pretty badly. Last, I added
the directories that I didn't want to copy to the new system.
<p>Once done with the copying - which took a while, even at 100Mb/s - I
did a "chroot /mnt/0 /bin/bash" on Ymir, which made this new filesystem
the root ("/") and ran a shell in it. Success! I thought of this as the
"three-quarter-way point"; most of the moving was done, and the only remaining
critical thing was making the system bootable. Of course, I had to do a
bit of system-specific setup: modifying "/etc/fstab" to reflect the correct
partitions, fixing "/etc/modules" to load the right ones, adjusting "/etc/lilo.conf"
and running "/sbin/lilo" to boot the right image... oh, whoops. Baldur
boots via "initrd"; the "initrd" image includes information about which
partition gets "pivoted to" as root, and that was different between Baldur
and Ymir. OK, then - I jumped over to Baldur and ran "mkinitrd" with the
"-r /dev/hda2" option, which built me a new "initrd" image with the correct
partition as the root. I "rsync"ed it to Ymir, and life was lookin' good.
<p>As a last step before rebooting, I ran "/sbin/lilo -v3", and... aaarrgh.
I got a message about the boot sector being made by a previous version
of LILO (remember that ancient Debian distro that had been on there?),
and the new one simply refused to rewrite it! &lt;sigh> Clearly, this would
not normally be an issue, but this time, it was a pain. Ah - LILO's manual
mentions the "QuickInst" script that is supposed to be used for initial
installs only - perfect. (See LILO's "doc" directory.) "QuickInst" walked
me through setting up some basics, and... &lt;laugh> it didn't work - the
"lilo.conf" that it wrote was too simple, and didn't match my setup. That
was OK, because it <i>did</i> rewrite the boot sector; I simply copied
the correct version of "lilo.conf" back into "/etc", re-ran "lilo -v3",
and All Was Cool.
<p>I then rebooted, swapped the BIOS settings back so that Ymir would boot
from the HD rather than the CDROM, watched a few errors fly by... and was
greeted with a login prompt. Hurrah! That was 90% of the way there; the
rest was just more tweaking. For the record, the things that produced the
errors were: "hdparm" disk tuning parameters had to be changed, and one
old module was still loading from "/etc/default/hotplug.usb". Other than
that, all that remained was much like setting up a new system, although
a lot less work. Let's see:
<ul>
<li>
Reconfigure X for different video card/monitor</li>

<li>
Load a different module for sound hardware</li>

<li>
Change the hostname in several "/etc" files ("grep -rl Baldur /etc")</li>

<li>
Run "ssh-keygen" for new SSH-2 "fingerprints" for Ymir</li>

<li>
Shut down "sshd" on Baldur</li>
</ul>
That was all of it. It's been more than a month now and I haven't had any
trouble at all. Sure, I've left a lot of stuff out of this description
in order to make myself look smarter - I probably rebooted, switching between
the LNX-BBC CD and the HD, about a dozen times because I'd forgotten "just
one little thing" - but the above was the critical path, the stuff that
had to happen to make it work. About two hours of work, and I had an up-to-date
Linux system that's all tuned to my preferences - setting it up from scratch
and getting it all adjusted would have taken much, much longer.
<h3>
After-Action Report</h3>
As a result of doing this, I learned a number of important things: a little
more knowledge about the "initrd" boot process, a little more experience
at fixing LILO problems, what exactly <b>is</b> affected when you move
from one system to another - and most important of all, how to do this
process and its associated pitfalls. As well, it's another tool in my "knowledge
toolbox" - and that's always a good thing. In fact, the laptop on which
I'm typing this - a brand-new Dell Inspiron - had Wind*ws XP on it just
a short while ago... :) It is now a very smoothly operating Linux 'top.
The actual time that I spent on the cloning, excluding the transfer time
(12GB takes a <b>while</b> to move across), was about 10-15 minutes; experience
is a wonderful thing.

<p>Happy Linuxing to all!

<H3>References</H3>
<UL>
<LI>man pages for "rsync", "ssh"/"sshd", "mke2fs"/"tune2fs", "chroot", "mkinitrd", "lilo"
<LI>Documentation (/usr/share/doc/lilo/Manual.txt.gz) for "lilo"
<LI>Documentation for the LNX-BBC CD
</UL>

<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>

Copyright &copy; 2002, Ben Okopnik.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR> 
Published in Issue 83 of <i>Linux Gazette</i>, October 2002</H5>
</STRONG></SMALL></CENTER>
<!-- *** END copyright *** -->
<HR>


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<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">Exploring Perl Modules - Part2: Creating Charts with GD::Graph</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/padala.html">Pradeep Padala</A></STRONG></BIG>

</TD></TR>
</TABLE>
<P>

<!-- END header -->




<h3>Introduction</h3>
<p>
If you have read my 
<A HREF="../issue81/padala.html">previous article on GD</A>, you might have
noticed that creating charts with the GD module is cumbersome.  (That article
also contains some general information about loading Perl modules.)  Martien
Verbruggen has created the GD::Graph module that allows easy creation of
charts. This module has useful functions to create various types of charts such
as bar charts, pie charts, line charts etc... The module is very useful in
creating dynamic charts depicting network statistics, web page access
statistics etc...
<p>
In this article, I will describe a general way of using the module
and also show a few examples of creating various charts.

<h3>Typical Way of Using the GD::Graph Module</h3>
<p>
A perl script using GD::Graph to create charts typically contains
the following things:
<ul>
<li> Prepare your data as an array of arrays. (More about this later)
<li> Decide on the type of chart. You would use a call like
<pre>
    $mygraph = GD::Graph::<b>chart</b>-&gt;new($width, $height);
</pre>
where chart can be <i>bars</i>, <i>lines</i>, <i>points</i>, <i>linespoints</i>,
<i>mixed</i> or <i>pie</i>. For example, if you wanted a bar chart, you 
would use
<pre>
    $mygraph = GD::Graph::bars-&gt;new($width, $height);
</pre>
<li> Set options for the graph as needed. This involves setting 'title', 
'x-label' etc... You can also set chart-type specific options.
<li>Plot the graph using the plot function
<pre>
    $myimage = $mygraph-&gt;plot(\@data);
</pre>
<li> Finally, you can save the image to a file or output for web. This is
similar to the way we have saved images 
<a href="../issue81/padala.html">using the GD module</a>.
</ul>

<h3>A Simple Example </h3>
<p>
Let's draw a simple chart following above steps. This script uses CGI to output
the image on to a web page.
<BR><A HREF="misc/padala/simple.pl.txt">[Text version of this listing.]</A> 

<pre>
<font color="#a020f0">#!/usr/local/bin/perl -w</font>
<font color="#0000ff"># Change above line to point to your perl binary</font>

<font color="#a52a2a"><b>use </b></font>CGI <font color="#ff00ff">'</font><font color="#ff00ff">:standard</font><font color="#ff00ff">'</font>;
<font color="#a52a2a"><b>use </b></font>GD::Graph::bars;
<font color="#a52a2a"><b>use strict</b></font>;

<font color="#0000ff"># Both the arrays should same number of entries.</font>
<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">@data</font> = ([<font color="#ff00ff">&quot;</font><font color="#ff00ff">Jan</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Feb</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Mar</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Apr</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">May</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Jun</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Jul</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Aug</font><font color="#ff00ff">&quot;</font>,
             <font color="#ff00ff">&quot;</font><font color="#ff00ff">Sep</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Oct</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Nov</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Dec</font><font color="#ff00ff">&quot;</font>],
            [<font color="#ff00ff">23</font>, <font color="#ff00ff">5</font>, <font color="#ff00ff">2</font>, <font color="#ff00ff">20</font>, <font color="#ff00ff">11</font>, <font color="#ff00ff">33</font>, <font color="#ff00ff">7</font>, <font color="#ff00ff">31</font>, <font color="#ff00ff">77</font>, <font color="#ff00ff">18</font>, <font color="#ff00ff">65</font>, <font color="#ff00ff">52</font>]);

<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">$mygraph</font> = GD::Graph::bars-&gt;<font color="#a52a2a"><b>new</b></font>(<font color="#ff00ff">500</font>, <font color="#ff00ff">300</font>);
<font color="#008b8b">$mygraph</font>-&gt;set(
    <font color="#ff00ff">x_label     </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Month</font><font color="#ff00ff">'</font>,
    <font color="#ff00ff">y_label     </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Number of Hits</font><font color="#ff00ff">'</font>,
    <font color="#ff00ff">title       </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Number of Hits in Each Month in 2002</font><font color="#ff00ff">'</font>,
) <font color="#a52a2a"><b>or</b></font> <font color="#a52a2a"><b>warn</b></font> <font color="#008b8b">$mygraph</font>-&gt;error;

<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">$myimage</font> = <font color="#008b8b">$mygraph</font>-&gt;plot(<font color="#008b8b">\@data</font>) <font color="#a52a2a"><b>or</b></font> <font color="#a52a2a"><b>die</b></font> <font color="#008b8b">$mygraph</font>-&gt;error;

<font color="#a52a2a"><b>print</b></font> <font color="#ff00ff">&quot;</font><font color="#ff00ff">Content-type: image/png</font><font color="#6a5acd">\n\n</font><font color="#ff00ff">&quot;</font>;
<font color="#a52a2a"><b>print</b></font> <font color="#008b8b">$myimage</font>-&gt;png;
</pre>
<p>
The output of the program can be seen <a href=misc/padala/simple_output.png>here</a>
<p>
The above program is pretty much self-explanatory. The <code>@data</code> 
variable
is an array of arrays. The first array represents the labels on X-axis and all 
the subsequent arrays present different datasets.

<h3>Tweaking the options</h3>
<p>
As you can see, the graph produced by above program is quite bland and simple.
We can tweak various options to produce better looking and customized graphs.
There are a multitude of options to control the various aspects of the graph.
Options are divided into two types: the options common to all types of graphs,
and the options specific to each type of graph.

<p>
Options can be set while creating the graph or with
<pre>
    $mygraph-&gt;set(attrib1 =&gt; value1, attrib2 =&gt; value2, ...);
</pre>
<p>
Let us write a script setting legends, a grid and few options.
<BR><A HREF="misc/padala/legend.pl.txt">[Text version of this listing.]</A> 
<pre>
<font color="#a020f0">#!/usr/local/bin/perl -w</font>
<font color="#0000ff"># Change above line to point to your perl binary</font>

<font color="#a52a2a"><b>use </b></font>CGI <font color="#ff00ff">'</font><font color="#ff00ff">:standard</font><font color="#ff00ff">'</font>;
<font color="#a52a2a"><b>use </b></font>GD::Graph::bars;
<font color="#a52a2a"><b>use strict</b></font>;

<font color="#0000ff"># Both the arrays should same number of entries.</font>
<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">@data</font> = ([<font color="#ff00ff">'</font><font color="#ff00ff">Fall 01</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Spr 01</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Fall 02</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Spr 02</font><font color="#ff00ff">'</font> ],
            [<font color="#ff00ff">80</font>, <font color="#ff00ff">90</font>, <font color="#ff00ff">85</font>, <font color="#ff00ff">75</font>],
            [<font color="#ff00ff">76</font>, <font color="#ff00ff">55</font>, <font color="#ff00ff">75</font>, <font color="#ff00ff">95</font>],
            [<font color="#ff00ff">66</font>, <font color="#ff00ff">58</font>, <font color="#ff00ff">92</font>, <font color="#ff00ff">83</font>]);

<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">$mygraph</font> = GD::Graph::bars-&gt;<font color="#a52a2a"><b>new</b></font>(<font color="#ff00ff">500</font>, <font color="#ff00ff">300</font>);
<font color="#008b8b">$mygraph</font>-&gt;set(
    <font color="#ff00ff">x_label     </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Semester</font><font color="#ff00ff">'</font>,
    <font color="#ff00ff">y_label     </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Marks</font><font color="#ff00ff">'</font>,
    <font color="#ff00ff">title       </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Grade report for a student</font><font color="#ff00ff">'</font>,
    <font color="#0000ff"># Draw bars with width 3 pixels</font>
    <font color="#ff00ff">bar_width   </font>=&gt; <font color="#ff00ff">3</font>,
    <font color="#0000ff"># Sepearte the bars with 4 pixels</font>
    <font color="#ff00ff">bar_spacing </font>=&gt; <font color="#ff00ff">4</font>,
    <font color="#0000ff"># Show the grid</font>
    <font color="#ff00ff">long_ticks  </font>=&gt; <font color="#ff00ff">1</font>,
    <font color="#0000ff"># Show values on top of each bar</font>
    <font color="#ff00ff">show_values </font>=&gt; <font color="#ff00ff">1</font>,
) <font color="#a52a2a"><b>or</b></font> <font color="#a52a2a"><b>warn</b></font> <font color="#008b8b">$mygraph</font>-&gt;error;

<font color="#008b8b">$mygraph</font>-&gt;set_legend_font(GD::gdMediumBoldFont);
<font color="#008b8b">$mygraph</font>-&gt;set_legend(<font color="#ff00ff">'</font><font color="#ff00ff">Exam 1</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Exam 2</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Exam 3</font><font color="#ff00ff">'</font>);
<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">$myimage</font> = <font color="#008b8b">$mygraph</font>-&gt;plot(<font color="#008b8b">\@data</font>) <font color="#a52a2a"><b>or</b></font> <font color="#a52a2a"><b>die</b></font> <font color="#008b8b">$mygraph</font>-&gt;error;

<font color="#a52a2a"><b>print</b></font> <font color="#ff00ff">&quot;</font><font color="#ff00ff">Content-type: image/png</font><font color="#6a5acd">\n\n</font><font color="#ff00ff">&quot;</font>;
<font color="#a52a2a"><b>print</b></font> <font color="#008b8b">$myimage</font>-&gt;png;
</pre>
<p>
The output of above program can be seen <a href=misc/padala/legend.png>here</a>

<h3>Graph with a logo in the background</h3>
<p>
Again as you can see, GD::Graph provides a flexible to way to create
customized graphs. Let's prepare another chart with a logo.
<pre>
Text version of the file can be found <a href=misc/padala/logo.pl.txt>here</a>
<font color="#a020f0">#!/usr/local/bin/perl -w</font>
<font color="#0000ff"># Change above line to point to your perl binary</font>

<font color="#a52a2a"><b>use </b></font>CGI <font color="#ff00ff">'</font><font color="#ff00ff">:standard</font><font color="#ff00ff">'</font>;
<font color="#a52a2a"><b>use lib</b></font> <font color="#ff00ff">'</font><font color="#ff00ff">/cise/homes/ppadala/mydepot/lib/perl5/site_perl</font><font color="#ff00ff">'</font>;
<font color="#a52a2a"><b>use </b></font>GD::Graph::bars;
<font color="#a52a2a"><b>use strict</b></font>;

<font color="#0000ff"># Both the arrays should same number of entries.</font>
<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">@data</font> = ([<font color="#ff00ff">'</font><font color="#ff00ff">Fall 01</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Spr 01</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Fall 02</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Spr 02</font><font color="#ff00ff">'</font> ],
            [<font color="#ff00ff">80</font>, <font color="#ff00ff">90</font>, <font color="#ff00ff">85</font>, <font color="#ff00ff">75</font>],
            [<font color="#ff00ff">76</font>, <font color="#ff00ff">55</font>, <font color="#ff00ff">75</font>, <font color="#ff00ff">95</font>],
            [<font color="#ff00ff">66</font>, <font color="#ff00ff">58</font>, <font color="#ff00ff">92</font>, <font color="#ff00ff">83</font>]);

<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">$mygraph</font> = GD::Graph::bars-&gt;<font color="#a52a2a"><b>new</b></font>(<font color="#ff00ff">500</font>, <font color="#ff00ff">300</font>);
<font color="#008b8b">$mygraph</font>-&gt;set(
    <font color="#ff00ff">x_label     </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Semester</font><font color="#ff00ff">'</font>,
    <font color="#ff00ff">y_label     </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Marks</font><font color="#ff00ff">'</font>,
    <font color="#ff00ff">title       </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Grade report for a student</font><font color="#ff00ff">'</font>,
    <font color="#0000ff"># Draw bars with width 3 pixels</font>
    <font color="#ff00ff">bar_width   </font>=&gt; <font color="#ff00ff">3</font>,
    <font color="#0000ff"># Sepearte the bars with 4 pixels</font>
    <font color="#ff00ff">bar_spacing </font>=&gt; <font color="#ff00ff">4</font>,
    <font color="#0000ff"># Show the grid</font>
    <font color="#ff00ff">long_ticks  </font>=&gt; <font color="#ff00ff">1</font>,
    <font color="#0000ff"># Show values on top of each bar</font>
    <font color="#ff00ff">show_values </font>=&gt; <font color="#ff00ff">1</font>,
) <font color="#a52a2a"><b>or</b></font> <font color="#a52a2a"><b>warn</b></font> <font color="#008b8b">$mygraph</font>-&gt;error;

<font color="#008b8b">$mygraph</font>-&gt;set(<font color="#ff00ff">logo </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">lglogo.png</font><font color="#ff00ff">'</font>);
<font color="#008b8b">$mygraph</font>-&gt;set(<font color="#ff00ff">logo_resize </font>=&gt; <font color="#ff00ff">0.5</font>);
<font color="#008b8b">$mygraph</font>-&gt;set(<font color="#ff00ff">logo_position </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">LL</font><font color="#ff00ff">'</font>);
<font color="#008b8b">$mygraph</font>-&gt;set_legend_font(GD::gdMediumBoldFont);
<font color="#008b8b">$mygraph</font>-&gt;set_legend(<font color="#ff00ff">'</font><font color="#ff00ff">Exam 1</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Exam 2</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Exam 3</font><font color="#ff00ff">'</font>);
<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">$myimage</font> = <font color="#008b8b">$mygraph</font>-&gt;plot(<font color="#008b8b">\@data</font>) <font color="#a52a2a"><b>or</b></font> <font color="#a52a2a"><b>die</b></font> <font color="#008b8b">$mygraph</font>-&gt;error;
<font color="#a52a2a"><b>print</b></font> <font color="#ff00ff">&quot;</font><font color="#ff00ff">Content-type: image/png</font><font color="#6a5acd">\n\n</font><font color="#ff00ff">&quot;</font>;
<font color="#a52a2a"><b>print</b></font> <font color="#008b8b">$myimage</font>-&gt;png;
</pre>
<p>
Output of above program can be seen <a href=misc/padala/logo_output.png>here</a>

<P>
Here's the Linux Gazette <A HREF="misc/padala/lglogo.png">logo</A> I used.
It's in PNG format.  The current version of GD::Graph doesn't recognize
any image types besides GIF (although it can write PNG, go figure).  I
submitted a 
<A HREF="http://www.cise.ufl.edu/~ppadala/perl/exploring/gd_graph/l
ogo_patch">patch</A> to fix this.  You can either apply the patch or use
an older version of GD or GD::Graph.


<h3>Graph with Lines </h3>
<p>
Some information can be better presented with line graphs. Here's an 
example showing a line graph.
<BR><A HREF="misc/padala/lines.pl.txt">[Text version of this listing.]</A> 
<pre>
<font color="#a020f0">#!/usr/local/bin/perl -w</font>
<font color="#0000ff"># Change above line to point to your perl binary</font>

<font color="#a52a2a"><b>use </b></font>CGI <font color="#ff00ff">'</font><font color="#ff00ff">:standard</font><font color="#ff00ff">'</font>;
<font color="#a52a2a"><b>use </b></font>GD::Graph::lines;
<font color="#a52a2a"><b>use strict</b></font>;

<font color="#0000ff"># Both the arrays should same number of entries.</font>
<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">@data</font> = ([<font color="#ff00ff">'</font><font color="#ff00ff">Fall 01</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Spr 01</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Fall 02</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Spr 02</font><font color="#ff00ff">'</font> ],
            [<font color="#ff00ff">80</font>, <font color="#ff00ff">90</font>, <font color="#ff00ff">85</font>, <font color="#ff00ff">75</font>],
            [<font color="#ff00ff">76</font>, <font color="#ff00ff">55</font>, <font color="#ff00ff">75</font>, <font color="#ff00ff">95</font>],
            [<font color="#ff00ff">66</font>, <font color="#ff00ff">58</font>, <font color="#ff00ff">92</font>, <font color="#ff00ff">83</font>]);

<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">$mygraph</font> = GD::Graph::lines-&gt;<font color="#a52a2a"><b>new</b></font>(<font color="#ff00ff">600</font>, <font color="#ff00ff">300</font>);
<font color="#008b8b">$mygraph</font>-&gt;set(
    <font color="#ff00ff">x_label     </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Semester</font><font color="#ff00ff">'</font>,
    <font color="#ff00ff">y_label     </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Marks</font><font color="#ff00ff">'</font>,
    <font color="#ff00ff">title       </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Grade report for a student</font><font color="#ff00ff">'</font>,
    <font color="#0000ff"># Draw datasets in 'solid', 'dashed' and 'dotted-dashed' lines</font>
    <font color="#ff00ff">line_types  </font>=&gt; [<font color="#ff00ff">1</font>, <font color="#ff00ff">2</font>, <font color="#ff00ff">4</font>],
    <font color="#0000ff"># Set the thickness of line</font>
    <font color="#ff00ff">line_width  </font>=&gt; <font color="#ff00ff">2</font>,
    <font color="#0000ff"># Set colors for datasets</font>
    <font color="#ff00ff">dclrs       </font>=&gt; [<font color="#ff00ff">'</font><font color="#ff00ff">blue</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">green</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">cyan</font><font color="#ff00ff">'</font>],
) <font color="#a52a2a"><b>or</b></font> <font color="#a52a2a"><b>warn</b></font> <font color="#008b8b">$mygraph</font>-&gt;error;

<font color="#008b8b">$mygraph</font>-&gt;set_legend_font(GD::gdMediumBoldFont);
<font color="#008b8b">$mygraph</font>-&gt;set_legend(<font color="#ff00ff">'</font><font color="#ff00ff">Exam 1</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Exam 2</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Exam 3</font><font color="#ff00ff">'</font>);
<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">$myimage</font> = <font color="#008b8b">$mygraph</font>-&gt;plot(<font color="#008b8b">\@data</font>) <font color="#a52a2a"><b>or</b></font> <font color="#a52a2a"><b>die</b></font> <font color="#008b8b">$mygraph</font>-&gt;error;

<font color="#a52a2a"><b>print</b></font> <font color="#ff00ff">&quot;</font><font color="#ff00ff">Content-type: image/png</font><font color="#6a5acd">\n\n</font><font color="#ff00ff">&quot;</font>;
<font color="#a52a2a"><b>print</b></font> <font color="#008b8b">$myimage</font>-&gt;png;
</pre>
<p>
Output of above program can be seen <a href=misc/padala/linesgraph.png>here</a>
<p>
Here I have used GD::Graph::lines to create the graph handle. But for this 
change, the program follows the same pattern for creating graphs.

<h3>A Pie Graph</h3>
<p>
Similarly we can create a pie chart. 
<BR><A HREF="misc/padala/pie.pl.txt">[Text version of this listing.]</A> 
<pre>
<font color="#a020f0">#!/usr/local/bin/perl -w</font>
<font color="#0000ff"># Change above line to point to your perl binary</font>

<font color="#a52a2a"><b>use </b></font>CGI <font color="#ff00ff">'</font><font color="#ff00ff">:standard</font><font color="#ff00ff">'</font>;
<font color="#a52a2a"><b>use </b></font>GD::Graph::pie;
<font color="#a52a2a"><b>use strict</b></font>;

<font color="#0000ff"># Both the arrays should same number of entries.</font>
<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">@data</font> = ([<font color="#ff00ff">'</font><font color="#ff00ff">Project</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">HW1</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">HW2</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">HW3</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">MidTerm</font><font color="#ff00ff">'</font>, <font color="#ff00ff">'</font><font color="#ff00ff">Final</font><font color="#ff00ff">'</font>],
            [<font color="#ff00ff">25</font>, <font color="#ff00ff">6</font>, <font color="#ff00ff">7</font>, <font color="#ff00ff">2</font>, <font color="#ff00ff">25</font>, <font color="#ff00ff">35</font>]);

<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">$mygraph</font> = GD::Graph::pie-&gt;<font color="#a52a2a"><b>new</b></font>(<font color="#ff00ff">300</font>, <font color="#ff00ff">300</font>);
<font color="#008b8b">$mygraph</font>-&gt;set(
    <font color="#ff00ff">title       </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Grading Policy for COP5555 course</font><font color="#ff00ff">'</font>,
    <font color="#ff00ff">'</font><font color="#ff00ff">3d</font><font color="#ff00ff">'</font>          =&gt; <font color="#ff00ff">1</font>,
) <font color="#a52a2a"><b>or</b></font> <font color="#a52a2a"><b>warn</b></font> <font color="#008b8b">$mygraph</font>-&gt;error;

<font color="#008b8b">$mygraph</font>-&gt;set_value_font(GD::gdMediumBoldFont);
<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">$myimage</font> = <font color="#008b8b">$mygraph</font>-&gt;plot(<font color="#008b8b">\@data</font>) <font color="#a52a2a"><b>or</b></font> <font color="#a52a2a"><b>die</b></font> <font color="#008b8b">$mygraph</font>-&gt;error;

<font color="#a52a2a"><b>print</b></font> <font color="#ff00ff">&quot;</font><font color="#ff00ff">Content-type: image/png</font><font color="#6a5acd">\n\n</font><font color="#ff00ff">&quot;</font>;
<font color="#a52a2a"><b>print</b></font> <font color="#008b8b">$myimage</font>-&gt;png;
</pre>
<p>
The output pie chart can be seen <a href=misc/padala/piechart.png>here</a>
<p>
The '3d' option draws the pie chart in 3d.
<h3> An Area Graph</h3>
<p>
An area graph shows the data as area under a line. 
<BR><A HREF="misc/padala/area.pl.txt">[Text version of this listing.]</A> 
<pre>
<font color="#a020f0">#!/usr/local/bin/perl -w</font>
<font color="#0000ff"># Change above line to point to your perl binary</font>

<font color="#a52a2a"><b>use </b></font>CGI <font color="#ff00ff">'</font><font color="#ff00ff">:standard</font><font color="#ff00ff">'</font>;
<font color="#a52a2a"><b>use </b></font>GD::Graph::area;
<font color="#a52a2a"><b>use strict</b></font>;

<font color="#0000ff"># Both the arrays should same number of entries.</font>
<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">@data</font> = ([<font color="#ff00ff">&quot;</font><font color="#ff00ff">Jan</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Feb</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Mar</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Apr</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">May</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Jun</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Jul</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Aug</font><font color="#ff00ff">&quot;</font>,
             <font color="#ff00ff">&quot;</font><font color="#ff00ff">Sep</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Oct</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Nov</font><font color="#ff00ff">&quot;</font>, <font color="#ff00ff">&quot;</font><font color="#ff00ff">Dec</font><font color="#ff00ff">&quot;</font>],
            [<font color="#ff00ff">23</font>, <font color="#ff00ff">5</font>, <font color="#ff00ff">2</font>, <font color="#ff00ff">20</font>, <font color="#ff00ff">11</font>, <font color="#ff00ff">33</font>, <font color="#ff00ff">7</font>, <font color="#ff00ff">31</font>, <font color="#ff00ff">77</font>, <font color="#ff00ff">18</font>, <font color="#ff00ff">65</font>, <font color="#ff00ff">52</font>]);

<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">$mygraph</font> = GD::Graph::area-&gt;<font color="#a52a2a"><b>new</b></font>(<font color="#ff00ff">500</font>, <font color="#ff00ff">300</font>);
<font color="#008b8b">$mygraph</font>-&gt;set(
    <font color="#ff00ff">x_label     </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Month</font><font color="#ff00ff">'</font>,
    <font color="#ff00ff">y_label     </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Number of Hits</font><font color="#ff00ff">'</font>,
    <font color="#ff00ff">title       </font>=&gt; <font color="#ff00ff">'</font><font color="#ff00ff">Number of Hits in Each Month in 2002</font><font color="#ff00ff">'</font>,
) <font color="#a52a2a"><b>or</b></font> <font color="#a52a2a"><b>warn</b></font> <font color="#008b8b">$mygraph</font>-&gt;error;

<font color="#a52a2a"><b>my</b></font> <font color="#008b8b">$myimage</font> = <font color="#008b8b">$mygraph</font>-&gt;plot(<font color="#008b8b">\@data</font>) <font color="#a52a2a"><b>or</b></font> <font color="#a52a2a"><b>die</b></font> <font color="#008b8b">$mygraph</font>-&gt;error;

<font color="#a52a2a"><b>print</b></font> <font color="#ff00ff">&quot;</font><font color="#ff00ff">Content-type: image/png</font><font color="#6a5acd">\n\n</font><font color="#ff00ff">&quot;</font>;
<font color="#a52a2a"><b>print</b></font> <font color="#008b8b">$myimage</font>-&gt;png;
</pre>
<p>
Output image can be seen <a href=misc/padala/areagraph.png>here</a>
<h3> Conclusion</h3>
<p>
The GD::Graph module provides a powerful and flexible way to create charts.
It's very useful for creating graphs dynamically for serving on web. 
<p>
I hope you have enjoyed reading this article. Next month, we will have a look
at the PerlMagic Module.




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<hr>
<CENTER><SMALL><STRONG>

Copyright &copy; 2002, Pradeep Padala.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR> 
Published in Issue 83 of <i>Linux Gazette</i>, October 2002</H5>
</STRONG></SMALL></CENTER>
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<A HREF="http://www.linuxgazette.com/">
<IMG ALT="LINUX GAZETTE" SRC="../gx/2002/lglogo_200x41.png" 
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</TD><TD WIDTH="380">


<center>
<BIG><BIG><STRONG><FONT COLOR="maroon">Handling Power Status Using snmptrapd</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/prasad.html">A B Prasad</A></STRONG></BIG>

</TD></TR>
</TABLE>
<P>

<!-- END header -->




<H3>If you are new to this topic</H3>
<P>Refer the following if you are new to SNMP</P>
<UL>
  <LI>net-snmp documentation
  <LI>rfc1678
  <LI>UPSHowto
  <LI>man pages of snmptrapd(8), snmptrapd.conf(8), and snmptrap(8) </LI></UL>
<H3>Net-snmp</H3>
<P>Various tools relating to the Simple Network Management Protocol
including:</P>
<UL>
  <LI>An extensible agent
  <LI>An SNMP library
  <LI>Tools to request or set information from SNMP agents
  <LI>Tools to generate and handle SNMP traps
  <LI>A version of the unix 'netstat' command using SNMP
  <LI>A graphical Perl/Tk/SNMP based mib browser.... </LI></UL>
<P>See the <A href="http://www.net-snmp.org/">NET-SNMP site</A>.</P>
<H3>snmptrapd</H3>
<P>Snmptrapd is an SNMP application that receives and logs snmp trap messages
sent to the SNMP-TRAP port (162) on the local machine. It can be configured to
run a specific program on receiving a snmp trap.</P>
<H3>snmptrapd.conf</H3>
<P>snmptrapd.conf is the configuration file(s) which define how the ucd-snmp
SNMP trap receiving demon operates when it receives a trap.</P>
<H3>ups-MIB</H3>
<P>RFC1628 document defines the managed objects for Uninterruptible Power
Supplies which are to be manageable via the Simple Network Management Protocol
(SNMP).</P>
<H3>How to use snmptrapd with powerh</H3>
<P>Please Note: I renamed 'powerd' as 'powerh' as here it is not a daemon but
only a trap handling routine</P>
<P>We had the powerh to handle the Power Status of the system. powerh
communicates with the UPS through the serial port. However, in a networked
system where a number of machines are using the same UPS it is not possible for
each system to directly communicate with the UPS. Most modern high capacity UPS
support the SNMP Protocol either directly or through a proxy. To handle various
power status follow these steps</P>
<P>1. To your snmptrapd.conf add the following lines</P><PRE>traphandle 33.2.3 powerh b
traphandle 33.2.4 powerh p
</PRE>
<P>2. Compile the following C <a href="misc/prasad/code.c.txt">code</a> by entering <I>cc powerh.c -o powerh</I>and
copy <I>powerh</I> to a directory in path like /usr/local/sbin/.
<BR><A HREF="misc/prasad/code.c.txt">[Text version of this listing.]</A> 
</P>


<PRE>
#include &lt;string.h&gt;
#include &lt;unistd.h&gt;
#include &lt;stdio.h&gt;
#include &lt;fcntl.h&gt;
#include &lt;signal.h&gt;


#define PWRSTAT "/etc/powerstatus"

void powerfail(int);

main(int argc, char* argv[]) {
    char s[1000];
    int i=0;
    while(i&lt;7) {
        scanf("%s",s);
        i++;
    }
    scanf("%s",s);
    if (!strcmp("b",argv[1]))
        if ((!strcmp(s,"33.1.6.3.3"))||(!strcmp(s,"upsMIB.upsObjects.upsAlarm.upsWellKnownAlarms.upsAlarmLowBattery")))
            powerfail(1);
    if (!strcmp("p",argv[1]))
        if ((!strcmp(s,"33.1.6.3.3"))||(!strcmp(s,"upsMIB.upsObjects.upsAlarm.upsWellKnownAlarms.upsAlarmLowBattery")))
            powerfail(0);
}
/* As the program may be activated in the event of other alarms as well, the inner 'if' are necessary */
void powerfail(int event) {
    int fd;
    unlink(PWRSTAT);
    if ((fd = open(PWRSTAT, O_CREAT|O_WRONLY, 0644)) &gt;= 0) {
          switch (event)
           {
           case 0:
                  write(fd, "OKWAIT\n", 7);
                   break;

             case 1:
                    write(fd, "FAIL\n", 5);
                     break;
             }
          close(fd);
       }
       kill(1, SIGPWR);
}



</PRE>
<P>3. Run snmptrapd on your system (you can configure it in the init
scripts)</P>
<P>The system will shutdown 2 minutes after receiving a 'battery low alarm' from
the UPS.  Then if power is OK before the shutdown it will cancel shutdown or as
configured in the powerfail and powerokwait lines in /etc/inittab</P> <h3>Code
Explanation
<H3></H3>
<P>When received a trap 33.2.3 (upsMIB.upsTraps.upsTrapAlarmEntryAdded) the
program is executed with a 'b' option. Program checks for the 'upsAlarmId' send
by the trap and if it is 33.1.6.3.3
(upsMIB.upsObjects.upsAlarm.upsWellKnownAlarms.upsAlarmLowBattery) it notfies
init that a power failure occurred. This alarm is added to the alarm table by
the UPS agent if the remaining battery run-time is less than or equal to
upsConfigLowBattTime. It is removed when the power is back and is acknowledged
by trap 33.2.4. The program then sends init a powerokwait message.</P>
<H3>Drawbacks</H3>
<UL>
  <LI>The program handles only two traps and look for only one type of alarm.
  The upsMIB has a number of alarms and the program is to be extended to handle
  all conditions.
  <LI>The obsolete method of informing init is used. This has to be changed.
  <LI>As I had no UPS that sends a snmp traps, I used the snmp trap
  generator
<PRE>
snmptrap -v 2c localhost public '' 33.2.3 33.2.3.0 s "33.1.6.3.3"
snmptrap -v 2c localhost public '' 33.2.4 33.2.4.0 s "33.1.6.3.3" 
</PRE>
I am not sure whether this is correct.
  <LI>The snmptrapd is to be run without -f option.
  <LI>Tested only on RedHat Linux 6.2.</LI></UL>
<H3>TODO</H3>
<P>I would like to see this few lines of code grow into a complete general
purpose UPS managing software capable of:</P>
<UL>
  <LI>Monitoring and changing all possible MIB of the upsMIB node
  <LI>Handle signals from multiple UPS
  <LI>Use data from a configuration file
  <LI>Handle authentication </LI></UL>
<P>All Suggestions, Criticisms,Contibutions (code and idea only - no cash please
;) ) etc. are welcome. You can contact me at <A
href="mailto://prasad_ab@yahoo.com">prasad_ab@yahoo.com</A>. See also my <a
href="www.geocities.com/prasad_ab">home page </a>.</P>



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<hr>
<CENTER><SMALL><STRONG>

Copyright &copy; 2002, A B Prasad.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR> 
Published in Issue 83 of <i>Linux Gazette</i>, October 2002</H5>
</STRONG></SMALL></CENTER>
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<A HREF="http://www.linuxgazette.com/">
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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">Qubism</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/harsem.html">Jon "Sir Flakey" Harsem</A></STRONG></BIG>
</CENTER>

</TD></TR>
</TABLE>
<P>

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<EM>These cartoons are scaled down to fit into LG.
	To see a panel in all its clarity, click on it.</EM>


<P>

<A HREF="misc/qubism/qb-lordof.jpg">
<IMG ALT="[cartoon]" SRC="misc/qubism/qb-lordof.jpg" 
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<BR CLEAR="all">

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<IMG ALT="[cartoon]" SRC="misc/qubism/qb-wireless.jpg" 
	WIDTH="640" HEIGHT="240"></A>
<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.





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Copyright &copy; 2002, Jon "Sir Flakey" Harsem.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR> 
Published in Issue 83 of <i>Linux Gazette</i>, October 2002</H5>
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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">Programming in Ruby, part 2</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/ramankutty.html">Hiran  Ramankutty</A></STRONG></BIG>
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<P>

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<H2><B>Review</B></H2>
<p>
A wide variety of applications from different domains need different 
levels of organization. We have seen the fundamentals of Ruby in 
<A HREF="../issue81/ramankutty.html">Part 1</A>, and now we jump on to the next
level of organization. 
</p>
<H2><B>Regular Expressions</B></H2>
<p>
In Ruby, a regular expression is quoted by '/' as in Perl and awk rather than
by quotation marks.
Regular expressions have an efficient expressive 
power, whenever you deal with patterns (as in pattern matching). Also 
some methods convert a string into a regular expression. 
<p></p>
<pre>print "abcdef" =~ /de/,"\n"
print "aaaaaa" =~ /d/,"\n"
^D
3
FALSE
</pre>
</p>
<p>
The operator `=~' is a matching operator with respect to regular 
expressions. It returns the position in a string where a match was 
found, or nil if the pattern did not match. It is interesting to see 
that regular expressions share a particular kind of vocabulary as shown 
below:
</p>
<DIV class="table"><PRE>   
	  [ ]     range specification. (e.g., [a-z] means a letter in range of from a to z)
          \w      letter or digit. same as [0-9A-Za-z_]
          \W      neither letter nor digit
          \s      blank character. same as [ \t\n\r\f]
          \S      non-space character.
          \d      digit character. same as [0-9].
          \D      non digit character.
          \b      word boundary (outside of range specification).
          \B      non word boundary.
          \b      back space (0x08) (inside of range specification)
          *       zero or more times repetition of followed expression
          +       one or more times repetition of followed expression
          {m,n}   at least n times, but not more than m times repetition
                  of followed expression
          ?       at least 0 times, but not more than 1 times repetition
                  of followed expression
          |       either preceding or next expression may match
          ( )     grouping
</PRE></DIV>
<p>
For example, `^f[a-z]+' means "f followed by repetition of letters in
range from `a' to `z'.  Now what if we want check whether a string fits a
given description say for example: "Starts with lower case `f', which 
is immediately followed by exactly one upper case letter, and 
optionally more junk after that, as long as there are no more lower
case characters. You will have to write a dozen lines in C, right? 
Admit it; you can hardly help yourself. In Ruby you just have to 
request the string to be matched with the regular expression
/^f[A-Z](^[a-z])*$/. This ability of regular expressions in string 
matching is often used in UNIX environment, typical example is `grep'. 
Let us get acquainted with regular expressions. Consider the program
given below:
</p>
<p></p>
<PRE> #Store this as regx.rb
 st = "\033[7m"
 en = "\033[m"
     
 while TRUE
	print "str&gt; "
	STDOUT.flush
	str = gets
	break if not str
	str.chop!
	print "pat&gt; "
	STDOUT.flush
	re = gets
	break if not re
	re.chop!
	str.gsub! re, "#{st}\\&amp;#{en}"
	print str, "\n"
end
print "\n"
# Now run ruby regx.rb
</PRE>
<p>The program requires inputs twice, once for a string and once for a 
regular expression. The test is performed for the string against the regular
expression, and matched parts are highlighted in reverse video.  Note
that this requires an ANSI terminal since it uses reverse video
escape sequences. Do not mind the details of the program. 
</p>
<p></p>
<pre>str&gt;foobar
pat&gt;^fo+
foobar
~~~
</pre>
<p>
We see that foo is reversed. Note that ``~~~'' is just for text-based 
browsers. We shall experiment with different inputs.
</p>
<p></p>
<pre>str&gt;asd987wonew06521
pat&gt;\d
asd987wonew06521
   ~~~     ~~~~~
str&gt;foozboozer
pat&gt;f.*z
foozboozer
~~~~~~~~
</pre>
<p>
Note that foozbooz is matched and not fooz. This is because here the
regular expression matches the longest possible substring. First 
glance interpretation is difficult. Try this:
</p>
<p></p>
<pre>str&gt; Wed Feb  7 08:58:04 JST 1996
pat&gt; [0-9]+:[0-9]+(:[0-9]+)?
Wed Feb  7 08:58:04 JST 1996
           ~~~~~~~~
</pre>
<p>
Now try to represent a hexadecimal number using regular expressions.
(for example: 0x123af00c as well as 0Xbc13590ae are hexadecimal numbers)
</p>
<p></p>
<pre>def chab(s)   # "contains hex in angle brackets"
	(s =~ /<0(x|X)(\d|[a-f]|[A-F])+>/) != nil
end
print chab "Not this one."
print "\n",chab "Maybe this? {0x35}" # use of wrong kind of brackets
print "\n",chab "Or this? <0x38z7e>" # Is this a HEX number
print "\n",chab "Okay, this: <0xfc0004>."
print "\n"
^D
false
false
false
true
</pre>
<H2><B>Iterators</B></H2>
<p>
Iterator means "one which does the same thing many times". Consider the
C code given below:
</p>
<p></p>
<pre>char *str;
for (str = "abcdefg"; *str != '\0'; str++) {
  /* process a character here */
}
</pre>
<p>
Note the abstraction provided by C's for(...) syntax to create loops, 
but in fact, the programmer has to know the internal structure of a
string to test *str with the null character.
</p>
<p>
Flexible support for iteration is one of the few features that mark a 
high-level language. Consider the following shell script (/bin/sh):
</p>
<p></p>
<pre>for i in *.[ch]; do
  # ...  something to do for each file
done
</pre>
<p>
All the C source and header files in the current directory are, 
processed, and the command shell handles the details of picking up and 
substituting file names one by one. Isn't this working at a higher 
level than C? What do you think ?
</p>
<p>
Considering the fact that, it is fine to provide iterators in a 
programming language for built-in data types, but it is a 
disappointment if we have to write low-level loops to iterate our 
dat types. In OOP, this can be a serious problem, since users often 
define one data type after another.
</p>
<p>
To  solve above matters, every OOP language has elaborate ways to make
iterations  easy, for example some languages provide class controlling
iteration,  etc.  On  the other hand, ruby allows us to define control
structures  directly.  In  term  of  ruby,  such  user-defined control
structures are called iterators.
</p>
<p>
Let us see few examples:
</p>
<p></p>
<pre>"abc".each_byte{|c| printf "%c\n", c}
^D
a
b
c
</pre>
<p>
Here, each_byte is an iterator for each character in the string. A 
local variable `c' is being used here, and each character is being 
substituted into it. This can be translated into something that looks
a lot like C code ...
</p>
<p></p>
<pre>s="abc"
i=0
while i &lt; s.length
	printf "%c\n",s[i]
	i+=1
end
^D
a
b
c
</pre>
<p>
... however, the each_byte iterator is simpler conceptually and is 
more likely to continuously work even if the string class happens to
be radically modified in the near future. One benefit of the iterators 
is their tendency of robustness in the face of such changes, and I 
think that is a characteristic of a good code.
</p>
Another iterator of string is each_line.
</p><p></p>
<pre>"a\nb\nc\n".each_line{|l| print l}
^D
a
b
c
</pre>
<p>
Every irksome task like finding delimiters for lines, generating 
sub strings etc. are undertaken by iterators.
</p>
<p>
Now, let's rewrite this example with for statement.

</p><p></p>
<pre>for l in "a\nb\nc\n"
        print l
end
^D
a
b
c
</pre>
<p>
The  for statement does iteration by way of an each iterator. String's 
each works the same as each_line as seen in the previous example.
</p>
<p>
Current iteration can be done or retried again from the top, by using 
a control structure `retry' in conjunction with an iterated loop. 
See below:
</p><p></p>
<pre>c = 0
for i in 0..4
	print i
     if i==2 and c==0
		c = 1
          print "\n"
          retry
     end
end
^D
012
01234
</pre>
<p>
The definition of an iterator may have an occurrence of `yield', which 
moves control to the block of code that is passed to the iterator (we 
will see more of this later). The example below defines the iterator 
repeat, which repeats a block of code the number of times specified in 
an argument.
</p>
<p></p>
<pre>def repeat(num)
	while num &lt; num
		yield
		num-=1
	end
end
repeat(4) {print "hello world\n"}
^D
hello world
hello world
hello world
</pre>
<p>
If it is not clear, then, print the value of num before and after the
occurrence of `yield'.
</p>
<p>
With `retry' one can define an iterator which works the same as `while',
but it is not practical due to slowness.
</p><p></p>
<pre>def MYWHILE(cond)
	return if not cond
	yield
	retry
end
i = 0
MYWHILE(i&lt;3) {print i,"\n" ;i+=1}
^D
0
1
2
</pre>
<p>
By now, I hope you must have got an idea about iterators. There are a 
few restrictions, but you can write your original iterators; and in 
fact, whenever you define a new data type, it is often convenient to 
define suitable iterators to go with it. In this sense this, the above 
examples `repeat() and `MYWHILE()' are not very useful. We will talk 
about practical iterators after we have a better understanding of what 
classes are.
</p>

<H2><B>Object Oriented Thinking</B></H2>
<p>
<B>`Object Oriented'</B> is indeed a very catchy phrase. Ruby claims to 
be an object oriented scripting language; but what does 'object 
oriented' exactly mean?
</p>
<p>
There have been a variety of answers to that question, all of which 
probably boil down to about the same thing. Before arguing and summing 
our definitions too quickly, let's think for a moment about the
traditional programming paradigm. 
</p>
<p>
Traditionally, a programming problem is attacked by coming up with 
some kinds of <B>data representations</B>, and <B>procedures</B> that 
operate on that data. We can associate terms inert, passive,and 
helpless with `data' under this model and that the data sits 
completely at the mercy of a large procedural body with which we 
associate terms active, logical, and all-powerful.
</p>
<p>
The problem with this approach is that programs are written by
programmers, who are only human and can only keep so much detail clear
in their heads at any one time.  As a project gets larger, its
procedural core grows to the point where it is difficult to remember how
the whole thing works.  Minor lapses of thinking and typographical 
errors become more likely to result in well-concealed bugs.  Complex 
and unintended interactions begin to emerge within the procedural core,
and maintaining it becomes like trying to carry around an angry squid 
without letting any tentacles touch your face.  There are guidelines 
for programming that can help to minimize and localize bugs within this
traditional paradigm, but there is a better solution that involves 
fundamentally changing the way we work.
</p>
<p>
What object-oriented does is to let us delegate most of he mundane 
and repetitive logical work <B>to the data itself</B>; we can then 
change our concept of data from <B>passive</B> to <B>active</B>. Put 
another way, 
</p>
<ul>
<li>we stop treating each piece of data as a box with an open lid that 
lets us reach in and throw things around.
<li>We start treating each piece of data as a working machine with a 
closed lid and a few well marked switches and dials.
</ul>
<p>
What is described above as a "machine" may be very simple or complex 
on the inside; we can't tell from the outside, and we don't allow 
ourselves to open up the machine (except when we are absolutely sure 
something is wrong with its design), so we are required to do things 
like flip the switches and read the dials to interact with the data.
Once the machine is built, we don't want to have to think about how it 
operates.
</p>
<p>
You might think we are just making more work for ourselves,but this 
approach tends to do a nice job of preventing all kinds of things from
going wrong.
</p>
<p>
Let's start with an example that is to simple to be of practical value, 
but should illustrate at least part of the concept. My 2-wheeler has a 
trip meter. Its job is to keep track of the distance it has travelled 
since the last time its reset button was pushed. How would we model 
this in a programming language? In C, the trip meter would just be a 
numeric variable, possibly of type float. The program would manipulate 
the variable by increasing its value in small increments, with 
occasional resets to zero when appropriate. What's wrong with that? A 
bug in the program would assign a bogus value to the variable, for any 
number of unexpected reasons. Anyone who has programmed in C knows what
it is like to spend hours or days tracking down such a bug whose cause 
seems absurdly simple once it has been found. (The moment of finding the
bug is commonly indicated by the sound of a loud slap to the forehead.)
</p>
<p>
In object-oriented context, the same problem can be attacked in a 
different manner. A programmer designing a trip meter is supposed not to 
ask "which of the familiar data-types comes closest to resembling the
thing" but instead be interested in "how exactly is this thing supposed 
to act?" The difference winds up being a profound one. It is necessary
to spend a little bit of time deciding exactly what an odometer is for, 
and how the outside world expects to interact with it. We decide to 
build a little machine with controls that allows us to increment it, 
reset it, read its value, and nothing else.
</p>
<p>
We don't provide a way for a trip meter to be assigned arbitrary values;
why?  because  we  all  know trip meters don't work that way. There are
only a few things you should be able to do with a trip meter, and those
are all we allow. Thus, if something else in the program mistakenly
tries to place some other value (say, the target temperature of the
vehicle's  climate  control) into the trip meter, there is an immediate
indication  of  what  went wrong. We are told when running the program
(or possibly while compiling, depending on the nature of the language)
that <B>we  are  not  allowed  to  assign  arbitrary values to Trip meter
objects</B>. The message might not be exactly that clear, but it will be
reasonably  close  to that. It doesn't prevent the error, does it? But
it  quickly  points us in the direction of the cause. This is only one
of several ways in which OO programming can save a lot of wasted time.
</p>
<p>
We  commonly take one step of abstraction above this, because it turns
out  to  be as easy to build a factory that makes machines as it is to
make an individual machine. We aren't likely to build a single
trip meter directly; rather, we arrange for any number of trip meters to
be built from a single pattern. The pattern (or if you like, the
trip meter  factory)  corresponds  to  what  we  call  a  class, and an
factory)  corresponds  to an <B>object</B>. Most OO languages require
a class to  be  defined before we can have a new kind of object, but 
ruby does not.
</p>
<p>
I would like to emphasize on the fact that the use of an OO language 
will not enforce proper OO design. Indeed it is possible in any 
language to write code that is unclear, sloppy, ill-conceived, buggy,
and wobbly all over. What ruby does for you (as opposed, especially, to
C++) is to make the practice  of OO programming feel natural enough 
that even when you are working  on a small scale you don't feel a 
necessity to resort to ugly code to save effort. We will be discussing 
the ways in which ruby accomplishes that admirable goal as this guide 
progresses; the next topic will be the "switches and dials" (object 
methods) and from there we'll move on to the "factories" (classes). Are 
you still with us? 
</p>




<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>

Copyright &copy; 2002, Hiran  Ramankutty.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR> 
Published in Issue 83 of <i>Linux Gazette</i>, October 2002</H5>
</STRONG></SMALL></CENTER>
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<A HREF="http://www.linuxgazette.com/">
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</TD><TD WIDTH="380">


<center>
<BIG><BIG><STRONG><FONT COLOR="maroon">Process Tracing Using Ptrace, part 2</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/sandeep.html">Sandeep S</A></STRONG></BIG>

</TD></TR>
</TABLE>
<P>

<!-- END header -->




<HR>
<EM>The basic features of ptrace were explained in 
<A HREF="../issue81/sandeep.html">Part I</A>. We saw a small example too. As I
said earlier, the main applications of ptrace are accessing memory or registers
of a process being run (either for debugging or for some evil purposes). So
first we should have some basic idea on the binary format of executables - then
only we know how and where to access them. So I shall give you a small tutorial
on ELF, the binary format used in Linux. In the last section of this article,
we find a small program which accesses the registers and memory of another one
and modifies them so as to change the output of that process, by injecting some
extra code.</EM>
<HR>
<P><B>Note:</B>  Please don't get confused. Definitely this is an article about ptrace,
not about ELF. But a basic knowledge of ELF is required for accessing the core images 
of processes. So it should be explained first.
<P>
<P>
<H2><A NAME="s1">1. What is ELF?</A></H2>

<P>ELF stands for Executable and Linking Format. It defines the format of 
executable binaries used on Linux - and also for relocatable, shared object and
core dump files too. ELF is used by both linkers and loaders. They view ELF
from two sides, so both should have a common interface.
<P>
<P>The structure of ELF is such that it has many sections and segments.
Relocatable files have section header tables, executable files have program
header tables, and shared object files have both. In the coming sections I shall
explain what these headers are.
<P>
<H2><A NAME="s2">2. ELF Headers</A></H2>

<P>Every ELF file has an ELF header. It always starts at 
offset 0 in the file. It contains the details of the binary file - should 
it be interpreted, what data structures are related to the file, etc.
<P>
<P>The format of the header is given below (taken from /usr/src/include/linux/elf.h)
<BLOCKQUOTE><CODE>
<HR>
<PRE>
#define EI_NIDENT       16

typedef struct elf32_hdr{
  unsigned char e_ident[EI_NIDENT];
  Elf32_Half    e_type;
  Elf32_Half    e_machine;
  Elf32_Word    e_version;
  Elf32_Addr    e_entry;  /* Entry point */
  Elf32_Off     e_phoff;
  Elf32_Off     e_shoff;
  Elf32_Word    e_flags;
  Elf32_Half    e_ehsize;
  Elf32_Half    e_phentsize;
  Elf32_Half    e_phnum;
  Elf32_Half    e_shentsize;
  Elf32_Half    e_shnum;
  Elf32_Half    e_shstrndx;
} Elf32_Ehdr;
</PRE>
<HR>
</CODE></BLOCKQUOTE>
<P>
<P>A small description on the fields is as follows
<P>
<OL>
<LI><P>e_ident : Contains information about how to treat the binary. Platform dependent.
<P>
</LI>
<LI><P>e_type  : Contains information on the type and how to use the binary. 
Types are relocatable, executable, shared object and core file.
<P>
</LI>
<LI><P>e_machine : As you have guessed, this field specifies the architecture - Intel 386, 
Alpha, Sparc etc.
<P>
</LI>
<LI><P>e_version : Gives the version of the object file.
<P>
</LI>
<LI><P>e_phoff : Offset from start to the first program header.
<P>
</LI>
<LI><P>e_shoff : Offset from start to the first section header.
<P>
</LI>
<LI><P>e_flags : Processor specific flags. Not used in i386
<P>
</LI>
<LI><P>e_ehsize : Size of the ELF header.
<P>
</LI>
<LI><P>e_phentsize &amp; e_shentsize : Size of program header and section header 
respectively.
<P>
</LI>
<LI><P>e_phnum &amp; e_shnum : Number of program headers and section headers. Program 
header table will be an array of program headers (e_phnum elements). Similar is 
the case of section header table.
<P>
</LI>
<LI><P>e_shstrndx : In the section header table a section contains the name of 
sections. This is the index to that section in the table. (see below)
<P>
</LI>
</OL>
<P>
<H2><A NAME="s3">3. Sections And Segments</A></H2>

<P>As said above, linkers treat the file as a set of logical sections described by a 
section header table, and loaders treat the file as a set of segments described by a 
program header table. The following section gives details on sections and 
segments/program headers.
<P>
<H2>3.1 ELF Sections and Section Headers</H2>

<P>The binary file is viewed as a collection of sections which are arrays of bytes 
of which no bytes are duplicated. Even though there will be helper information to 
correctly interpret the contents of the section, the applications may interpret 
in its own way.
<P>
<P>There will be a section header table which is an array of section headers.
The zeroth entry of the table is always NULL and describe no part of the 
binary. Each section header has the following format:
(taken from /usr/src/include/linux/elf.h)
<P>
<BLOCKQUOTE><CODE>
<HR>
<PRE>
typedef struct elf32_shdr {
  Elf32_Word sh_name;           /* Section name, index in string tbl (yes Elf32) */
  Elf32_Word sh_type;           /* Type of section (yes Elf32) */
  Elf32_Word sh_flags;          /* Miscellaneous section attributes */
  Elf32_Addr sh_addr;           /* Section virtual addr at execution */
  Elf32_Off sh_offset;          /* Section file offset */
  Elf32_Word sh_size;           /* Size of section in bytes */
  Elf32_Word sh_link;           /* Index of another section (yes Elf32) */
  Elf32_Word sh_info;           /* Additional section information (yes Elf32) */
  Elf32_Word sh_addralign;      /* Section alignment */
  Elf32_Word sh_entsize;        /* Entry size if section holds table */
} Elf32_Shdr;
</PRE>
<HR>
</CODE></BLOCKQUOTE>
<P>
<P>Now the fields in detail.
<P>
<OL>
<LI><P>sh_name : This contains an index into the section contents of the 
e_shstrndx  string table. This index is the start of a null terminated string 
to be used as the name of the section. There are many, a few are given.
<P>
<UL>
<LI>.text This section holds executable instructions of a program</LI>
<LI>.data This section holds initialized data that contributes to the programs image.</LI>
<LI>.init: This section holds executable instructions that contribute to the process 
initialization code.</LI>
</UL>
<P>
</LI>
<LI><P>sh_type : Section type such as program data, symbol table, string table etc..
<P>
</LI>
<LI><P>sh_flags : Contains information such as how to treat the contents of the section.
<P>
</LI>
<LI><P>sh_addralign : Contains the alignment requirement of section contents,
typically 0/1 (both meaning no alignment) or 4.
<P>
</LI>
</OL>
<P>
<P>The remaining fields seem to be self explaining.
<P>
<H2>3.2 ELF Segments And Program Headers</H2>

<P>The ELF segments are used during loading ie, when the image of the process 
is made in the core. Each segment is described by a program header. There 
will be a program header table in the file (usually near the ELF header).
The table is an array of program headers. The format of the program header 
is as follows.
<P>
<BLOCKQUOTE><CODE>
<HR>
<PRE>
typedef struct
{
  Elf32_Word    p_type;                 /* Segment type */
  Elf32_Off     p_offset;               /* Segment file offset */
  Elf32_Addr    p_vaddr;                /* Segment virtual address */
  Elf32_Addr    p_paddr;                /* Segment physical address */
  Elf32_Word    p_filesz;               /* Segment size in file */
  Elf32_Word    p_memsz;                /* Segment size in memory */
  Elf32_Word    p_flags;                /* Segment flags */
  Elf32_Word    p_align;                /* Segment alignment */
} Elf32_Phdr;
</PRE>
<HR>
</CODE></BLOCKQUOTE>
<P>
<OL>
<LI><P>p_type : Gives information on how to treat the contents. It gives the type
of program header such as 
<P>
<UL>
<LI>unused </LI>
<LI>loadable </LI>
<LI>Dynamic linking information</LI>
<LI>reserved</LI>
</UL>
<P>etc ..
<P>
</LI>
<LI><P>p_vaddr : relative virtual address the segment expects to be loaded.
<P>
</LI>
<LI><P>p_paddr : physical address of the segment expects to be loaded into the
memory.
<P>
</LI>
<LI><P>p_flags : Contains protection flags - read/write/execute permissions
<P>
</LI>
<LI><P>p_align : Contains the alignment for the segment in memory. If the
segment is of type loadable, then the alignment will be the expected page size.
<P>
</LI>
</OL>
<P>
<P>Remaining fields appear to be self explaining.
<P>
<H2><A NAME="s4">4. Loading The ELF File</A></H2>

<P>We have got some idea about the structure of ELF object files. Now we have to 
know how and where these files are loaded for execution. Usually we just type 
program name at the shell prompt. In fact a lot of interesting things happen
after  the return key is hit. 
<P>
<P>First the shell calls the 
standard libc function which in turn calls the kernel routine. Now the ball is 
in kernel's court. The kernel opens the file and finds out the type/format of
the executable. Then loads ELF and needed libraries, initializes the program's
stack, and finally passes control to the program code.
<P>
<P>The program gets loaded to 0x08048000 (you can see this in /proc/pid/maps)
and the stack starts from 0xBFFFFFFF (stack grows to numerically small addresses).
<P>
<H2><A NAME="s5">5. Code Injection</A></H2>

<P>We have seen the details of the programs being loaded in the memory. So when
a process is given and its memory space known, we can trace it (if we have
permission) and access the private data structures of the process. It is very 
easy to say this, but not that easy to do it. Why not make a try? 
<P>
<P>First of all, let's write a program to access the registers of another 
program and 
modify it. Here we use the following values of <CODE>request</CODE>.
<P>
<UL>
<LI>PTRACE_ATTACH : Attach to the process pid.
</LI>
<LI>PTRACE_DETACH : Detach from the process pid. 
<P><B>Note :</B> Do not forget to call this, otherwise the process will
stay in stopped mode and is hard to recover.
<P>
</LI>
<LI>PTRACE_GETREGS : This copies the process' registers into the struct
pointed by data (addr is ignored). This structure is 
<CODE>struct user_regs_struct</CODE> defined as this, in asm/user.h.

<BLOCKQUOTE><CODE>
<HR>
<PRE>
struct user_regs_struct {
                long ebx, ecx, edx, esi, edi, ebp, eax;
                unsigned short ds, __ds, es, __es;
                unsigned short fs, __fs, gs, __gs;
                long orig_eax, eip;
                unsigned short cs, __cs;
                long eflags, esp;
                unsigned short ss, __ss;
        };
</PRE>
<HR>
</CODE></BLOCKQUOTE>

</LI>
<LI>PTRACE_SETREGS : Does just the reverse of GETREGS.
</LI>
<LI>PTRACE_POKETEXT : This copies 32 bits from the address pointed by data
in the addr address of the traced process.</LI>
</UL>
<P>
<P>Now we are going to inject a small piece of our code to image of the process being traced and force the process to execute our code by changing its instruction pointer.
<P>
<P>What we do is very simple. First we attach the process, and then read the 
register contents of the process. Now insert the code which we want to get 
executed in some location of the stack and the instruction pointer of the 
process is changed to that location. Finally we detach the process. Now the 
process starts to execute and will be executing the injected code.
<P>
<P>We have two source files, one is the assembly code to be injected and 
other is the one which traces the process. I shall provide a small program 
which we may trace.
<P>
<P>The source files
<P>
<UL>
<LI>
<A HREF="./misc/sandeep/Tracer.c">Tracer.c</A></LI>
<LI>
<A HREF="./misc/sandeep/Code.S">Code.S</A></LI>
<LI>
<A HREF="./misc/sandeep/Sample.c">Sample.c</A></LI>
</UL>
<P>
<P>Now compile the files.
<P>
<BLOCKQUOTE><CODE>
<HR>
<PRE>
#cc Sample.c -o loop
#cc Tracer.c Code.S -o catch
</PRE>
<HR>
</CODE></BLOCKQUOTE>
<P>
<P>Go to another console and run the sample program by typing
<P>
<BLOCKQUOTE><CODE>
<HR>
<PRE>
#./loop
</PRE>
<HR>
</CODE></BLOCKQUOTE>
<P>
<P>Come back and execute the tracer to catch the looping process and change its
output. Type
<P>
<BLOCKQUOTE><CODE>
<HR>
<PRE>
#./catch `ps ax | grep "loop" | cut -f 3 -d ' '`
</PRE>
<HR>
</CODE></BLOCKQUOTE>
<P>
<P>Now go to where the sample program 'loop' runs and watch what happens. 
Definitely your play with ptrace has begun.
<P>
<H2><A NAME="s6">6. Looking Forward</A></H2>

<P>In the first part we traced a process and counted its number of instructions.
In this part we studied the ELF file structure and injected a small piece of 
code into some process. In next part I would expect to access the memory space
of some process. Till then, bye from Sandeep S.




<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>

Copyright &copy; 2002, Sandeep S.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR> 
Published in Issue 83 of <i>Linux Gazette</i>, October 2002</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">DVD Authoring</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/stoddard.html">Chris Stoddard</A></STRONG></BIG>

</TD></TR>
</TABLE>
<P>

<!-- END header -->




<p>
 This document provides the steps necessary to make a DVD which will play in a stand alone DVD player, using Linux and a DVD+RW or DVD-RW drive.
</p>

<h2>Table of Contents</h2>
<ul TYPE=""> 
  <li>1. Introduction
  <li>2. Hardware Required
  <li>3. Software Required
  <li>4. Recording, encoding and burning the video
  <li>5. Fixing audio sync problems
  <li>6. Final Note
</ul>

<h2>Introduction</h2>
<p>
  I am constantly amazed at how easy it is to accomplish things in Linux once someone works out the process.  DVD Authoring is a good example of this, all the parts are in place, all the information is available and it is a relatively easy thing to do, but no where is there a single document showing how to accomplish it.  Authoring DVD under Linux is still in its infancy, there are no tools for menus or any advanced features, for now all we can do is single straight DVD stream, which is enough for home videos and saving TV shows.  I will not be discussing video editing here, I assume you will either be recording from TV or have a video tape you wish to transfer to a DVD.
</p>

<h2>Hardware Required:</h2>
<p>
 I'm not going into much detail about installing the hardware, if you don't know how to install your hardware, I have provided links to articles for help.
</p>

<ul TYPE="">
  <li>Video Capture device:  I am using a Hauppauge WinTV PCI card, TV tuner cards are cheap and easy to come by, and are well supported by Linux.  There are more expensive solutions which will get you better video quality, but support under Linux varies widely.  <a HREF="http://www.linuxgazette.com/issue62/silva.html">Video Applications on Your Linux Box</a>

  <li>DVD+RW or DVD-RW drive:  I am using an old Ricoh MP5120A DVD+RW drive I purchased refurbished for $150.  Luckily these drives install exactly the same way as a standard CDRW drive.  You also need to be able to play DVD's on you system.  Please be sure your stand alone DVD player supports the format of your burner.  <a HREF="http://www.linuxgazette.com/issue81/durodola.html">Playing DVDs on Linux</a> and <a HREF="http://linuxgazette.com/issue57/stoddard.html">CD-Writing with an ATAPI CDR Mini-HOWTO</a>

  <li>Fast CPU and a huge hard drive:  I am personally using an Athlon 1600XP, 384 MB of RAM and a 40 GB hard Drive.  I probably wouldn't even attempt this with less than 1 Ghz CPU and 20 GB of free hard drive space.

</ul>

<h2>Software Required:</h2>

<p>
  Each of these packages has their own install process, please follow the instructions for each individual package.
</p>

<ul TYPE=""> 
  <li>xawtv comes with streamer, which we will use for recording the video: <a HREF="http://bytesex.org/xawtv/">xawtv</a>

  <li>mjpeg-tools is used for encoding the recorded video into a DVD compatible format: <a HREF="http://mjpeg.sourceforge.net/">mjpeg-tools</a>

  <li>dvdauthor is the key piece of software, without it, we would not be able to do this.  This package generates the IFO files required by DVD player.  There is no automatic install for this program, simply run make, then copy the binaries to /usr/local/bin: <a HREF="http://sourceforge.net/project/showfiles.php?group_id=59028">dvdauthor</a>

  <li>dvdrtools is a fork of cdrtools which we will use to build the iso and write to newer DVD-RW drives: <a HREF="http://www.freesoftware.fsf.org/dvdrtools/">dvdrtools</a>

  <li>dvd+rw tools is used to burn to older DVD+RW format, this is only necessary if you have a first generation DVD+RW drive.  If you have a newer DVD-RW drive this package is not needed: <a HREF="http://fy.chalmers.se/~appro/linux/DVD+RW/">dvd+rw tools</a>
</ul>

<p>
  dvd+rw tools has no Makefile.  You can build the binaries doing this:
</p>

<pre>
    gcc dvd+rw-format.c
    mv a.out dvd+rw-format
    cp dvd+rw-format /usr/local/bin
    gcc growisofs.c
    mv a.out growisofs
    cp growisofs /usr/local/bin
</pre>

<h2>Recording, encoding and burning the video:</h2>
<p>
  Recording the video is the most important step, the size of the video and the frame rate must be right.  The following command uses streamer, which comes with xawtv to record the video:
</p>

<pre>
  streamer -n ntsc -t 60:00 -s 720x480 -r 30 -o stream.avi -f mjpeg -F stereo -c /dev/video0
</pre>

<p>
  The -n switch is for format, if you use PAL, change ntsc to pal. The -t switch is record time in minutes.  -s is the size of the video, in the USA, we use NTSC which requires the video to be 720x480 if you use PAL, change this to 720x576.  -r is the frame rate, for NTSC use 30, for PAL use 24, -c is the video device, change it if need be.  The rest of the switches should remain unchanged.
</p>

<p>
  The next thing to do is to properly encode the audio and video into something a DVD player can read.  The tools we need for this are from mjpeg-tools.  This command line strips the audio out of our avi file and encodes it to mp2 audio.  The -V switch actually is for VCD compatibility, but works for us here:
</p>

<pre>
  lav2wav +p stream.avi | mp2enc -V -o audio.mp2
</pre>

<p>
  Next we strip out the video and encode it to mpeg video.  This part is what takes the longest, the faster your system is the better.  The important switches here are -f 8, which ensures the video will be DVD compatible and -n n, which is for NTSC, if you are using PAL change it to -n p:
</p>

<pre>
  lav2yuv +p stream.avi | mpeg2enc -n n -f 8 -s -r 16 -o video.m1v
</pre>

<p>
  Now we need to join the two encoded files.  Be sure to use the -f 8 switch for DVD compatible video:
</p>

<pre>
  mplex -f 8 audio.mp2 video.m1v -o complete.mpg
</pre>

<p>
  In order for our disc to be played in a stand alone DVD player, the directory structure HAS to be perfect, so please make sure you type the next several commands exactly as shown, in the order shown:
</p>

<pre>
  mkdir dvd
  mkdir dvd/VIDEO_TS
</pre>

<p>
  Next we need an Table of Content IFO file, type:
</p>

<pre>
  tocgen > dvd/VIDEO_TS/VIDEO_TS.IFO
</pre>

<p>
  Now we want to copy our encoded video file into the structure and give it the correct permissions, type:
</p>

<pre>
  cp complete.mpg dvd/VIDEO_TS/VTS_01_1.VOB
  chmod u+w dvd/VIDEO_TS/*.VOB
</pre>

<p>
  IFO and BUP files provide DVD players with information specific to the video file it is trying to play, ifogen looks at the video and extracts the information needed.  To generate the needed files use this command line:
</p>

<pre>
  ifogen -f dvd/VIDEO_TS/VTS_01_1.VOB > dvd/VIDEO_TS/VTS_01_0.IFO
  (cd dvd/VIDEO_TS; for i in *.IFO; do cp $i `basename $i .IFO`.BUP; done)
</pre>

<p>
  Now we need to generate an iso image which can be burned to a DVD disc.  Be sure you are using mkisofs version from dvdrtools, which supports the DVD files system:
</p>

<pre>
  mkisofs -dvd-video -udf -o dvd.iso dvd/
</pre>

<p>
  And, finally, we can burn our disc.  If you are using an older first generation DVD+RW drive, the disc will need to be formated before the image can be burned, use the following commands, replacing srcd0 with the device name of your drive:
</p>

<pre>
  dvd+rw-format -f /dev/srcd0
  growisofs -Z /dev/srcd0=dvd.iso
</pre>

<p>
If you are using a newer DVD-RW, no formating is necessary, dvdrecord will do the job:
</p>

<pre>
  dvdrecord -dao speed=2 dev=0,0,0 dvd.iso
</pre>

<h2>Fixing audio sync problems</h2>
<p>
  The most common problem with this process is audio sync.  The first thing you should try is optimizing your hard drive with hdparm, turn on 32 bit I/O and DMA, it looks something like this:
</p>

<pre>
  hdparm -c 1 -d 1 /dev/hda
</pre>

  Next, load the bttv driver with the gbuffers=10 option:

<pre>
  modprobe bttv gbuffers=10
</pre>

<p>
  This should fix any audio sync problems, if it does not, you may need to use the -O n option when running mplex.  This delays the video by n mSeconds.  The problem with this is it is a trial and error process and often leaves the joined video file in a state that causes ifogen to segfault.  It may also be possible to record the video at a lower size, say 352x240, then use yuvscaler from the mpjeg-tools to resize it to 720x480, but I have not tried this.
</p>

<h2>Final Notes:</h2>
<p>
  This process will not give you "Buy in the Store" DVD quality video, the quality will depend largely on the quality of your capture source, so you should use the best quality settings you can when recording anything on video tape you intend to burn to DVD.  This process takes several hours, I use the shell script below to do the work for me, while I am at work or in bed sleeping.  100 minutes of video will require about 11 GB to record, 2 GB to encode and 1 GB for the iso image.  Your mileage will vary.
</p>

<A HREF="misc/stoddard/make-dvd.sh.txt">Text version of make-dvd.sh</A>
<pre>
-----make-dvd.sh-----
#!/bin/sh

# Cleans out any left over files and makes the necessary directories
rm -r -f dvd video dvd.iso
mkdir dvd
mkdir dvd/VIDEO_TS
mkdir video

# Changes the channel on the TV tuner card
v4lctl setstation 3
# Records the video stream
streamer -n ntsc -t 60:00 -s 720x480 -r 30 -o video/stream.avi -f mjpeg -F stereo -c /dev/video0

# Encodes the video stream
lav2wav +p video/stream.avi | mp2enc -V -o video/audio.mp2
lav2yuv +p video/stream.avi | mpeg2enc -n n -f 8 -s -r 16 -o video/video.m1v
mplex -f 8 video/audio.mp2 video/video.m1v -o video/complete.mpg

# Builds DVD image from the encoded video
# This portion of the script was lifted directly from
# the writedvd script which comes with the dvdauthor tools
tocgen > dvd/VIDEO_TS/VIDEO_TS.IFO
cp video/complete.mpg dvd/VIDEO_TS/VTS_01_1.VOB
chmod u+w dvd/VIDEO_TS/*.VOB
ifogen -f dvd/VIDEO_TS/VTS_01_1.VOB > dvd/VIDEO_TS/VTS_01_0.IFO
(cd dvd/VIDEO_TS; for i in *.IFO; do cp $i `basename $i .IFO`.BUP; done)
mkisofs -dvd-video -udf -o dvd.iso dvd/

# Burns the DVD for 1st Generation DVD+RW
# Comment out the dvd+rw-format line if the disc is already formated and
# contains no data. 
# Comment these two lines out if you are using a newer drive
dvd+rw-format -f /dev/srcd0
growisofs -Z /dev/srcd0=dvd.iso

# Burns DVD for more modern DVD formats like DVD-RW
# Uncomment this line if you are using a newer drive
#dvdrecord -dao speed=2 dev=0,0,0 dvd.iso
-----make-dvd.sh-----
</pre>




<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>

Copyright &copy; 2002, Chris Stoddard.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR> 
Published in Issue 83 of <i>Linux Gazette</i>, October 2002</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">Risk-Free Resource Allocation for I/O Memory-Mapped Device Drivers</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/thangaraju.html">Dr B Thangaraju</A></STRONG></BIG>

</TD></TR>
</TABLE>
<P>

<!-- END header -->




<FONT color=navy><H2>Abstract</H2></FONT color=navy>

	<p>A device driver is an entry point to access a device. Developing a
device driver is not as simple a task as writing application programs. Since
any dynamically-loaded driver module is attached to the existing kernel, any
error in the driver will crash the entire system. Resource allocation for a
device is one of the main concerns for device driver developers. The device
resources are I/O memory, IRQs and ports. This article presents a risk-free way
of allocating resource for an I/O memory mapped device for a dynamically loaded
Linux device driver, and is written so that less experienced Linux users can follow
along.</p>

<FONT color=navy><H2>Introduction</H2></FONT color=navy>

<p>      In the rapidly developing IT field, new devices are constantly being
developed and we see an increasingly wide variety of Input and Output devices.
The I/O subsystem allows a process to communicate with peripheral devices such
as disks, floppies, CD-ROMs, terminals, printers and networks. Kernel modules
that control devices are known as device drivers.  The I/O subsystem handles
the movement of data between memory and peripheral devices.  The type of the
devices can be classified into character and block depending on the way the
system accesses the device. In general, the character devices like keyboard,
mouse, console and modem are accessed as a stream of bytes. However, the block
devices like Hard disk, floppy and CD-ROM move blocks of data to and from the
system. </p>

<p>      The kernel interacts with these devices through device drivers.  A
device driver is a collection of functions used to access any particular
device.  One of the important features of Linux is that the device driver
module can be inserted dynamically into the existing kernel.  Then the driver
module will become part of the kernel and can access the kernel functions.
 In the same way, the loaded driver can be removed dynamically. If the driver is not explicitly removed, it will be persistent in the system until we reboot the machine.</p>

<p>	The most frequent job of any driver is transferring data between
the computer and its external environment.  The external environment consists
of a variety of external devices, including secondary memory devices,
communications equipment and terminals. Three techniques are possible for I/O
operations: programmed I/O, Interrupt - driver I/O and Direct Memory
Access (DMA).  The programmed I/O devices pass the data from system to device
or vice versa in two different ways: I/O port and I/O memory mapped. This
article explains the basic concept of I/O memory mapped devices and the macros
used by the device driver for allocating I/O memory regions for the device and
expounds the concept with well tested device driver code. Since the driver
module is part of the kernel, any attempt to allocate existing address to your
device will crash the system. So the sample driver will first probe whether the
address range is free or not, if it is already in use by other device it will
return immediately with an error, otherwise it will allocate the given address range to
your device. </p>


<FONT color=navy><H2>Basics of I/O memory mapped device</H2></FONT color=navy>

<p>	Device drivers are extremely device dependent. The driver framework
should take responsibility of how the CPU interacts with the device. PIO and
DMA are the two ways of moving data between the kernel and the device. PIO
requires the CPU to move data  to or from the device as each byte is ready,
by responding to an interrupt or polling. For DMA
devices, the kernel gives the source address, the destination address and the size of
the data in memory. The device can transfer the data without CPU intervention,
and when the data is moved it will send an interrupt to notify the kernel of the
completion. Typically, slow devices like modem and line printers are PIO
devices, while disks and graphics terminals are DMA devices.  </p>

<p>	For PIO devices, there are two ways to pass data from the device to
system memory.  Which way a system uses depends on its architecture. For instance, Intel x86
architectures supports I/O port, and Motorola 680x0 maintains memory mapped
device I/O. Moreover, most of the ISA (Industry Standard Architecture) devices
belong to the I/O support allocation and 
  PCI (Peripheral Component Interconnect) devices uphold I/O memory mapped
allocation.  Several parameters that a driver must know are, for example, the
hardware's actual I/O addresses or memory range. Sometimes you need to pass
parameters to a driver to help it in finding its own device or to
enable/disable specific features. 
In my previous article in Linux Focus
(<A HREF="http://linuxfocus.org/English/November2002/article264.meta.shtml">
http://linuxfocus.org/English/November2002/article264.meta.shtml</A>), I explained the
fundamentals of device controllers and intricacies of the fail safe port
allocation for Linux device drivers From the driver developer perspective, the
allocation of I/O memory for a device has some similarity with allocation of
I/O ports because both are based on similar internal mechanisms. So it is
redundant to explain again the basics of device controller and the functions of
status and control registers for transferring data from or to device to system
memory.</p>


<FONT color=navy><H2>Macros used for I/O memory address allocation </H2></FONT color=navy>

<p>To probe whether the address range is already in use or not, use the following
macro in driver.
</p>
<FONT color=#8281e10><h3>int check_mem_region (unsigned long start, unsigned
long length);</h3></FONT color=#8281e10>

<p>Here, the first argument <b>start</b> is the starting address of the I/O
memory and <b>length</b> is the size of the address range. The function returns
zero if the address range is available otherwise returns less than zero.
To register the given I/O memory regions, the macro is 
</P>
<FONT color=#8281e10><h3> void request_mem_region (unsigned long start,
unsigned long length, char
*device_name);</h3></FONT color=#8281e10>


<p>The string argument <b>char *device_name</b> is the name of device, which
will own the I/O memory regions from start address to length size.
	Before the device is unregistered, the allocated I/O memory regions
should be released for other devices.  
</P>

<FONT color=#8281e10><h3>void release_mem_region (unsigned long start, unsigned
long length);</h3></FONT color=#8281e10>

<p>The above function will de-allocate the I/O memory regions.</p>

<br><br><br>
<FONT color=navy><H2>Example Driver Code for I/O memory region
allocation</H2></FONT color=navy>

<table BORDER COLS=1 WIDTH="52%" BGCOLOR="silver" >
<tr> <td>
<p>#include &lt;linux/module.h>
<br>#include &lt;linux/init.h>
<br>#include &lt;linux/fs.h>
<br>#include &lt;linux/ioport.h>
<p>static int Major, result;
<br>struct file_operations fops;
<p>unsigned long start = 0, length = 0;
<p>MODULE_PARM (start, "l");
<br>MODULE_PARM (length, "l");
<p>int Wipro_init (void) {
<br>&nbsp;&nbsp;&nbsp; Major = register_chrdev (0, "Wipro_device", &amp;fops);
<br>&nbsp;&nbsp;&nbsp; if (Major &lt; 0)
<br>&nbsp;&nbsp;&nbsp; {
<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; printk (" Major number allocation
is failed \n");
<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return (Major);
<br>&nbsp;&nbsp;&nbsp; }
<br>&nbsp;&nbsp;&nbsp; printk (" The Major number of the device is %d \n",
Major);
<p>&nbsp;&nbsp;&nbsp; result = check_mem_region (start, length);
<br>&nbsp;&nbsp;&nbsp; if (result &lt; 0)
<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; {
<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
printk ("Allocation for I/O memory range is failed: Try other range\n");
<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;
return (result);
<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; }
<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; request_mem_region (start,
length, "Wipro_device");
<br>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; return 0;
<br>}
<p>void Wipro_cleanup (void) {
<br>&nbsp;&nbsp;&nbsp; release_mem_region (start, length);
<br>&nbsp;&nbsp;&nbsp; printk (" The I/O memory region is released successfully
\n");
<p>&nbsp;&nbsp;&nbsp; unregister_chrdev (Major, "Wipro_device");
<br>&nbsp;&nbsp;&nbsp; printk (" The Major number is released successfully
\n");
<br>}
<p>module_init (Wipro_init);
<br>module_exit (Wipro_cleanup);
</td> </tr> </table> 

	<p>The above program is saved as io_mem.c.  First four lines are the
headers, which are included to access kernel macros and functions. Next is the
variable and file_operations structure declaration. The macro MODULE_PARM is
the driver modules parameter for assigning value of any variable during the
module loading. It will accept two arguments, first one is the variable name
and the second one is data type of the variable. In this code, "<b>l</b>"
means long int. </p>
	<p>In Wipro_init and Wipro_cleanup functions are explicit
initialization and cleanup for this driver module. The modern mechanism
recommends this approach for marking init_module and cleanup_module. The
Wipro_init function first registers the Wipro_device and allocates major number
dynamically. Then it will probe the given address, <b>if the address is already
in use, the function will return an error, otherwise it will allocate the
address range for the device</b>. The Wipro_cleanup function deallocate the I/O
memory region before unregistering the device name and major number.</p>
<p>The file is compiled with 2.4 kernel and has been created io_mem.o  object file. 


	The following <b>device</b> and <b>iomem</b> file contains part of the existing data in my computer shown below. 
</p>
<table BORDER COLS=1 WIDTH="52%" BGCOLOR="silver" >
<tr> <td>
<p><b>$cat /proc/devices</b>
<br>Character devices:
<br>  1 mem
<br>  2 pty 
<br>...
<br>180 usb
</p>

<p><b>$cat /proc/iomem</b>
<br>00000000-0009fbff : System RAM
<br>...
<br>e0000000-e3ffffff : Silicon Integrated Systems [SiS] 620 Host
<br>ffff0000-ffffffff : reserved </p>
</td> </tr> </table> 

<p>	The module is loaded by a command, 
<b>$insmod ./io_mem.o start=0xeeee0000 length=0xeeee</b>. 
After loading successfully, it is evident that the device is registered with
the existing devices list with major number 254 and the given memory range is
allocated and shown in devices and iomem file respectively as shown below. </p>
<table BORDER COLS=1 WIDTH="52%" BGCOLOR="silver" >
<tr> <td>

<p><b>$cat /proc/devices</b>
<br>Character devices:
<br>  1 mem
<br>  2 pty
<br>...
<br>180 usb
<br><b><FONT color=red>254 Wipro_device</b> </FONT color=red>
<br>
</P>

<p><b>$cat /proc/iomem</b>
<br>00000000-0009fbff : System RAM
<br>...
<br>e0000000-e3ffffff : Silicon Integrated Systems [SiS] 620 Host
<br><b><FONT color=red>eeee0000-eeeeeeed : Wipro_device</b> </FONT color=red>
<br>ffff0000-ffffffff : reserved </p>

 </tr> </table> 

<br><br><br><FONT color=navy><H2>Conclusion </H2></FONT color=navy>
<p> We discussed the importance of the risk-free resource allocation for I/O memory mapped
devices for Linux
device drivers. We examined the basics of I/O memory mapped devices, the
macros for 
I/O memory address allocation. We explained the practical approach
of how to allocate resource for 
I/O memory mapped devices with the well tested device driver code.
We verified the code is 
explained and the device register and memory range address allocation. 
</p>

<H2><FONT color=navy>Acknowledgment</H2></FONT color=navy>

I would like to acknowledge <b>Mr.V.Jayasurya and Dr. Sanjay Gupta
</b>,Talent Transformation, Wipro Technologies, India.   

<H2><FONT color=navy> References </H2></FONT color=navy>
 1. Linux Device Drivers (2nd Edition), by Alessandro Rubini and Jonathan Corbet. 
<br>       The book is available from O'Reilly  :  <A HREF="http://linux.oreilly.com/">http://linux.oreilly.com/</A>




<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>

Copyright &copy; 2002, Dr B Thangaraju.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR> 
Published in Issue 83 of <i>Linux Gazette</i>, October 2002</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">Apache Log Analysis Using Python</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/tougher.html">Rob Tougher</A></STRONG></BIG>

</TD></TR>
</TABLE>
<P>

<!-- END header -->




<dl>
<dt><a href=#1>1. Introduction</a>
<dt><a href=#2>2. The Framework</a>
<dd><a href=#2.1>2.1 First pass - Awk attempt</a>
<dd><a href=#2.2>2.2 Next pass - Python to the rescue</a>
<dt><a href=#3>3. Example Handlers</a>
<dd><a href=#3.1>3.1 Return visitors</a>
<dd><a href=#3.2>3.2 Referring domains</a>
<dt><a href=#4>4. Files</a>
<dt><a href=#5>5. Conclusion</a>
</dl>

<a name=1></a>
<h3>1. Introduction</h3>

<p>
I use the <a href="http://httpd.apache.org/">
Apache HTTP Server</a> to run my
<a href="http://www.robtougher.com">web site</a>. 
When a visitor requests a page from the site, Apache
records the following information in a file named "access_log":
</p>

<ul>
<li>The IP address of the computer requesting the page
<li>The name of the page being requested
<li>The date and time of the request
<li>The page that referred the visitor to the requested page
</ul>


<p>
Until recently I used a combination of command line utilities 
(grep, tail, sort, wc, less, awk) to extract
this information from the access log. 
But some complex calculations were difficult and time-consuming
to perform using these tools. 
I needed a more powerful solution - 
a programming language to crunch the data.
</p>

<p>
Enter <a href="http://www.python.org">Python</a>. Python is
fast becoming my favorite language, and was the perfect tool
for solving this problem. I created a framework in Python for 
performing generic text file analysis, and then utilized
this framework to glean information from my Apache access log.
</p>

<p>
This article first explains the framework, and 
then describes two examples that use it. My hope
is that by the end of this article you will be able
to use this framework for analyzing your own text files.
</p>

<a name=2></a>
<h3>2. The Framework</h3>

<a name=2.1></a>
<h4>2.1 First pass - Awk attempt</h4>

<p>
When trying to solve this problem I initially turned to 
<a href="http://www.gnu.org/software/gawk/gawk.html">Gawk</a>, 
an implementation of the Awk language. Awk is primarily used
to search text files for certain pieces of data. The following is 
a basic Awk script:
</p>



<p>Listing 1: 
<a href="misc/tougher/count_lines.awk.txt">count_lines.awk</a></p>
<pre>
#!/usr/bin/awk -f

BEGIN {
	count = 0
}

{ count++ }

END {
	print count
}
</pre>


<p>
This script prints the number of lines in a file. You can
run it by typing the following at a command prompt:
</p>

<pre>
prompt$ ./count_lines.awk access_log
</pre>

<p>
Awk reads in the script, and does the following:
</p>

<ul>
<li>Runs the code in the BEGIN block.
<li>Runs the middle block of code for each line in "access_log".
<li>Runs the code in the END block.
</ul>

<p>
I liked this processing model. It made sense to me - 
first run some initialization code, 
next process the file line by line, 
and finally run some cleanup code. It seemed perfectly
suited to the task of analyzing text files.
</p>

<p>
Awk gave me trouble, though. It was very difficult to create
complex data structures - I was jumping through hoops for
tasks that should have been much more straightforward. 
So after some time I started looking for an alternative.
</p>

<a name=2.2></a>
<h4>2.2 Next pass - Python to the rescue</h4>

<p>
My situation was this: I liked the Awk processing model, 
but I didn't like the language itself. And I liked Python, but 
it didn't have Awk's processing model. So I decided
to combine the two, and came up with the current framework.
</p>

<p>
The framework resides in 
<a href="misc/tougher/awk.py.txt">awk.py</a>.
This module contains one class, <code>controller</code>, which
implements the following methods:
</p>

<ul>
<li><code>__init__(file)</code> - the constructor, which takes a 
file object to process.
<li><code>subscribe(handler)</code> - subscribes a handler to the controller.
<li><code>run()</code> - processes the file.
<li><code>print_results()</code> - prints the results of the process.
</ul>


<p>
A <i>handler</i> is a class that implements a defined set 
of methods. Multiple handlers 
can be subscribed to the controller at any given time. Every
handler must implement the following methods:
</p>


<ul>
<li><code>begin()</code> - gets called once before the file is processed.
<li><code>process_line(line)</code> - gets called for each line of the file.
<li><code>end()</code> - gets called after the file is processed.
<li><code>description()</code> - gets called from 
<code>controller.print_results()</code>. It should
return a description of the handler.
<li><code>result()</code> - also called from 
<code>controller.print_results()</code>. 
It should return the results of the class' calculations.
</ul>


<p>
You create handlers, subscribe them to the controller, and then
run the controller. The following is a simple example with one handler:
</p>



<p>Listing 2: <a href="misc/tougher/count_lines.py.txt">count_lines.py</a></p>
<pre>
# Standard sys module
import sys

# Custom awk.py module
import awk

class count_lines:

	def begin(self):
		self.m_count = 0

	def process_line(self, s):
		self.m_count += 1

	def end(self):
		pass

	def description(self):
		return "# of lines in the file"

	def result(self):
		return self.m_count


#
# Step 1: Create the Awk controller
#
ac = awk.controller(sys.stdin)

#
# Step 2: Subscribe the handler
#
ac.subscribe(count_lines())

#
# Step 3: Run
#
ac.run()

#
# Step 4: Print the results
#
ac.print_results()
</pre>



<p>
You can run this script using the following command:
</p>

<pre>
prompt$ cat access_log | python count_lines.py
</pre>

<p>
The results of the script should be printed to the console.
</p>



<a name=3></a>
<h3>3. Example Handlers</h3>

<p>
Now that the framework was in place, I had to figure
out how I was going to use it. I came up with many ideas, but
the following two were the top priorities.
</p>

<a name=3.1></a>
<h4>3.1 Return visitors</h4>

<p>
The first question that I wanted to answer using my new framework
was the following:
</p>

<ul>
<li><i>How many people have returned to the site more than N times?</i>
</ul>


<p>
My thinking was this: if people return often, they must enjoy
the site, right? The following script answers the
above question:
</p>


<p>
Listing 3: return_visitors (can be found in 
<a href="misc/tougher/handlers.py.txt">handlers.py</a>)
</p>

<pre>
class return_visitors:

	def __init__(self, n):
		self.m_n = n
		self.m_ip_days = {}

	def begin(self):
	    pass

	def process_line(self, s):

		try:
			array = s.split()
			ip = array[0]
			day = array[3][1:7]

			if self.m_ip_days.has_key(ip):

				if day not in self.m_ip_days[ip]:
					self.m_ip_days[ip].append(day)

			else:
				self.m_ip_days[ip] = []
				self.m_ip_days[ip].append(day)

		except IndexError:
			pass



	def end(self):

		ips = self.m_ip_days.keys()
		count = 0

		for ip in ips:

			if len(self.m_ip_days[ip]) > self.m_n:
				count += 1

		self.m_count = count


	def description(self):
		return "# of IP addresses that visited more than %s days" % self.m_n

	def result(self):
		return self.m_count
</pre>


<p>
The script stores the number of days that each IP address has visited
the site. When the file is finished processing, it returns how
many IP addresses have visited more than N times.
</p>


<a name=3.2></a>
<h4>3.2 Referring domains</h4>

<p>
Another thing I wanted to know was how people found out about the
site. I was getting a decent amount of traffic, and I wasn't sure
why. I kept asking myself:
</p>


<ul>
<li><i>Where are all these people coming from?</i>
</ul>

<p>
I guess you shouldn't argue with a site that's popular. But
I was curious to know how people were learning about my site.
So I wrote the following script:
</p>


<p>Listing 4: referring_domains (can be found in 
<a href="misc/tougher/handlers.py.txt">handlers.py</a>)
</p>

<pre>
class referring_domains:

	def __init__(self):
		self.m_domains = {}

	def begin(self):
		pass

	def process_line(self, line):

		try:
			array = line.split()
			referrer = array[10]

			m = re.search('//[a-zA-Z0-9\-\.]*\.[a-zA-z]{2,3}/',
				      referrer)

			length = len(m.group(0))
			domain = m.group(0)[2:length-1]

			if self.m_domains.has_key(domain):
				self.m_domains[domain] += 1
			else:
				self.m_domains[domain] = 1

		except AttributeError:
			pass
		except IndexError:
			pass


	def end(self):
		pass


	def description(self):
		return "Referring domains"


	def sort(self, key1, key2):
		if self.m_domains[key1] > self.m_domains[key2]:
			return -1
		elif self.m_domains[key1] == self.m_domains[key2]:
			return 0
		else:
			return 1


	def result(self):

		s = ""
		keys = self.m_domains.keys()
		keys.sort(self.sort)

		for domain in keys:
			s += domain
			s += " "
			s += str(self.m_domains[domain])
			s += "\n"

		s += "\n\n"

		return s
</pre>


<p>
This script stores the referral information
for each request, and generates a list of
referring domains, sorted by frequency.
</p>

<p>
I ran the script and found that most of the referrals came from my own site.
This makes sense - when a visitor moves from one page to another on
the site, the referring domain for the page is my web site's
domain. But I did find some interesting entries in the referral
list, and my question about site traffic was answered.
</p>


<a name=4></a>
<h3>4. Files</h3>

<p>
The following files contain the code from this article:
</p>

<ul>
<li><a href="misc/tougher/count_lines.awk.txt">count_lines.awk</a> - 
a basic Awk script
<li><a href="misc/tougher/awk.py.txt">awk.py</a> - 
the <code>controller</code> class
<li><a href="misc/tougher/count_lines.py.txt">count_lines.py</a> - 
<code>count_lines</code> handler
<li><a href="misc/tougher/handlers.py.txt">handlers.py</a> - 
<code>return_visitors</code> and <code>referring_domains</code> handlers
</ul>

<a name=5></a>
<h3>5. Conclusion</h3>


<p>
In this article I described how I use Python to process my
Apache HTTP Server access log. Hopefully I explained my techniques
clearly enough so that you can use them for your text files.
</p>




<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>

Copyright &copy; 2002, Rob Tougher.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR> 
Published in Issue 83 of <i>Linux Gazette</i>, October 2002</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">Subnetting your local network with DHCP</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/ward.html">Alan Ward</A></STRONG></BIG>

</TD></TR>
</TABLE>
<P>

<!-- END header -->




<p><b>Why subnet?</b></p>

<p>As hardware prices go down and local networks grow larger, a new size of 
local network is becoming common: the size in between the small office
(5-10 hosts) and the large corporate building-sized LAN (more than 50 hosts).</p>

<p>With less than 10 hosts, it is generally easy to manage the network: 
all hosts get on to the same Ethernet segment, and security -- if necessary -- 
is implemented at host level: passwords and such. With more than 50 
hosts, you can generally obtain funding for managed switches than can 
define virtual networks (VLANs). The Accounting Department will go on 
one VLAN, Production on another and so forth. Every host will have access 
to other hosts in its VLAN and to the company servers, but not across 
VLANs. Security is managed at both host and network levels.</p>

<p>On middlish-sized local networks however, we often must put all hosts
on the same segment once more. Recent cheap LAN switches are capable of
handling traffic between up to 50 hosts easily. However, switches with 
VLAN capability are much more expensive. Well-known brands are selling for 
upwards of US $1200 for a 24-port switch, which may be worth it -- but is 
completely out of many budgets. Mine for one.</p>

<p><b>DHCP and subnetworks</b></p>

<p>One of the local networks I administer in the school I work in 
is a long string of non-managed Ethernet switches. This is basically because 
of how the building was initially drawn up. On this, I must handle traffic 
from several different types of host; to simplify let's say I have 
teacher-level traffic (group A) and student-level traffic (group B). 
These must not mix: I do not want people from each group accessing the 
other group's files or 
printers (passwords tend to be weaker than I would like).</p>

<p>The simplest way to separate the groups at logical level is to give 
each group a different IP network address. For example, group A gets 
addresses on network 192.168.10.0 (e.g. 192.168.10.12), while group B 
get addresses on network 192.168.20.0 (e.g. 192.168.20.34). Servers 
that are present on both must have an address on each network.</p>

<p align=center><img src="misc/ward/map.jpg"><br>
<i>Our network topology</i></p>

<p>A DHCP server is a good way of doing this. This is the service you 
access when using a dial-up Internet connection: you connect to 
your ISP, who assigns you a temporary public IP address. Most Linux
distributions include a DHCP server, which can also be used on a 
local network.</p>

<p>Initially, you can give the DHCP server a range of IP addresses 
to distribute: for example 192.168.1.100 to 192.168.1.199. Any host
that starts up and asks for an address will get one of these. After the
host is switched back off, the address will be liberated and can be
re-used on another host if needed.</p>

<p>But Ethernet cards all carry a unique identification number, called 
a MAC address. This is a 12-digit hexadecimal number that is assigned 
by the manufacturer, and that is guaranteed to be different from any 
other Ethernet card, anywhere in the world. A DHCP server can be configured 
to use this MAC address to always assign the same IP address to the host.</p>

<p>Using this, we can make a list of the MAC addresses of the hosts in 
our group A, and make DHCP serve them fixed IP addresses on the 192.168.10.0 
subnet. The MAC addresses of hosts in group B are served addresses on 
the 192.168.20.0 subnet, and hosts that are not on either list (visitors' 
laptops, for example) get an address on subnet 192.168.1.0 .

<p>DHCP has an advantage over VLANs in this respect: VLANs are defined 
for physical network ports, while DHCP uses card addresses. With a VLAN, 
if you physically change your computer's network connection -- as in 
moving from one room to another -- you may also change its VLAN. With 
DHCP however, its subnet assignation will remain the same.</p>

<p><b>Setting up DHCP</b></p>

<p>On most Linux distributions, the DHCP server is called dhcpd, and 
is started with the standard scripts (the same as httpd, postfix, ...). 
It can be found in RPM form, as for example in <u>dhcp-3.0-3mdk.i386.rpm</u>. 
If you already have it installed on your system, try the dhcpd and 
dhcpd.conf man pages.</p>

<p>To begin, I used the webmin utility to set up a basic subnet DHCP 
service. Notice that this service has to be on network 192.168.0.0 
with netmask 255.255.0.0 . This is because it must be accessible 
from al subnets.</p>

<p align=center><img src="misc/ward/main.jpg"><br></p>

<p>I then set up each specific host, specifying it's name, hardware 
MAC address and the IP address I want to serve to it. Note the 
IP address, now on subnet 192.168.10.0 .</p>

<p align=center><img src="misc/ward/client.jpg"><br></p>

<p>To obtain the Ethernet MAC address, most cards have it printed 
on a label sticking to the card. It yours does not, you can skip this 
step for the moment. Finish setting up the DHCP service and fire up 
the hosts one by one. As each host obtains an IP address (on subnet 
192.168.1.0 for the time being), you will see it appear in file 
<u>/var/lib/dhcp/dhcpd.leases</u>. For example: </p>

<p><pre>
lease 192.168.1.198 { 
   hardware ethernet 00:00:b4:38:cf:6a;  
   client-hostname "bis";
}
</pre></p>

<p>Please note that <strong>only</strong> addresses obtained from 
the general subnet will appear here; not when you have given a 
host a fixed address.</p>

<p>Finish setting up the fixed addresses for hosts on the DHCP server.</p>

<p>Start or restart the DHCP server. Hosts should now be obtaining 
their assigned IP addresses. You can see this on a Linux host with 
the <u>ifconfig</u> utility. On a Windows box, you can use <u>winipcfg</u> 
under Win95/98/ME, or <u>ipconfig</u> (in a terminal window) under WinNT/2k.</p>

<p>But network masks should now still be the default 255.255.0.0 . This is 
not good, as hosts on subnets 192.168.10.0 and 192.168.20.0 can see each 
others (try a ping). We should now go to each host definition for dhcpd, 
and in the "edit client options" set its subnet mask as 255.255.255.0 and 
its default router to 192.168.X.1 for subnet 192.168.X.0 . For example, 
on subnet 192.168.10.0:</p>

<p align=center><img src="misc/ward/client1.jpg"><br></p>

<p>Remember to also set the network mask to 255.255.255.0 for the 
general 192.168.0.0 subnet client options.

<p>You can edit the <u>/etc/dhcpd.conf</u> file by hand. It may even 
be more clear than the webmin interface. This is what you could have:</p>

<p><pre>
#
# main subnet, accessed by default by hosts we do not know
#
subnet 192.168.0.0 netmask 255.255.0.0 {
	option subnet-mask 255.255.255.0;
	option routers 192.168.1.1;
	range 192.168.1.101 192.168.1.199;
	}

# 
# host definition, one for each known host on our LAN
#
host bis {
	option subnet-mask 255.255.255.0;
	option routers 192.168.10.1;
	hardware ethernet 00:00:b4:38:cf:6a;    # 12-digit hex MAC address
	fixed-address 192.168.10.34;
	}

</pre></p>

<p><b>Making the server accessible</b></p>

<p>In the above example, we made 192.168.X.1 the default router for each 
subnet 192.168.X.0 . But for the time being, our server has IP address 
192.168.1.1 -- which means that:<br>

<ul><li>hosts on subnet 192.168.10.0 will try to 
obtain an IP address</li>
<li>they will obtain such an address from server 192.168.1.1</li>
<li>this address will be on subnet 192.168.10.0, netmask 255.255.255.0</li>
<li>they are now unable to contact server 192.168.1.1 <strong>which is 
on another subnet!!!</strong></li>
</ul></p>

<p>This is why our server must have an extra IP address for each 
subnet: 192.168.10.1, 192.168.20.1, etc. This can easily be set up 
by creating virtual network cards eth0:1, eth0:2, etc. with webmin:</p>

<p align=center><img src="misc/ward/virtual.jpg"><br></p>

<p>You can also create this by hand. On a Mandrake or Red Hat distribution, 
the files are in <u>/etc/sysconfig/network-scripts</u>. You 
should already have a file called <u>ifcfg-eth0</u>. Copy this as 
<u>ifcfg-eth0:1</u>, <u>ifcfg-eth0:2</u>, ... changing the addresses 
and netmasks as appropriate. For example, for eth0:1 :</p>

<p><pre>
BROADCAST=192.168.10.0
DEVICE=eth0:1
NETMASK=255.255.255.0
IPADDR=192.168.10.1
NETWORK=192.168.10.0
ONBOOT=yes
BOOTPROTO=none
</pre></p>

<p>This is basically all you need. You may now have to enable routing on the 
server, for example if you 
are using it to access Internet. But be careful to disable routing between 
local subnets; 192.168.X.0 should not be able to see 192.168.Y.0 . Use 
a firewalling package such as iptables to block this. You can also use 
this to block or allow Internet access from any or all subnets if you wish.</p>

<hr>

<p>PS. Should anybody want to translate this article: I wrote it in
the spirit of  the GPL software licence. i.e. you are free (and 
indeed encouraged) to copy, post and translate it -- but please, 
PLEASE, send me notice by email!  I like to keep track of translations --
it's good for the curriculum :-)</p>


<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>

Copyright &copy; 2002, Alan Ward.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR> 
Published in Issue 83 of <i>Linux Gazette</i>, October 2002</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 <FONT COLOR="red"><STRONG>SCARY!!!</STRONG></FONT></I></SMALL>
</TD><TD WIDTH="380">


<center>
<BIG><BIG><STRONG><FONT COLOR="maroon">The Back Page</FONT></STRONG></BIG></BIG><BR>
<STRONG>By <A HREF="../authors/orr.html">Mike ("Iron") Orr</A></STRONG></BIG>

</TD></TR>
</TABLE>
<P>

<!-- END header -->




<ul>
<li><a HREF="#news">Gazette News</a>
<li><a HREF="#wacko">Wacko Topic of the Month #1</a>
<li><a HREF="#nottag">Not the Answer Gang</a>
<li><a HREF="#other">In Other News...</a>
</ul>


<a name="news"></a>
<P> <hr> <P> 
<!--====================================================================-->

<center><H3><font color="maroon">Gazette News</font></H3></center>

<P> <HR> <P> 
<!--======================================================================-->
<P>

LG now has Author pages.  Starting this
issue, every author gets a page with his or her contact information, bio, and
links to all the articles s/he has written.  The "By &lt;author&gt;" link
at the top of each article will now go to the Author's page.
There's also an 
<A HREF="../authors/index.html">author index</A> if you want to browse.
The former TAG Bios have also turned into Author pages, and the 
<A HREF="../tag/bios.html">TAG Bios index page</A>  has been turned into
a set of links.

<P> Over time, we will gradually clean up the links in the back isues
and try to eliminate symlinks from LG.  Some people read LG offline on 
systems without symbolic links, and find it difficult when the files
don't exist.  However, we will maintain the "current/" link at least,
pointing to the current issue.


<a name="wacko"></a>
<P> <hr> <P> 
<!--====================================================================-->

<center><H3><font color="maroon">Wacko Topic of the Month</font></H3></center>

<p> <hr> <p> 
<!--====================================================================-->

The Register <A
HREF="http://www.theregister.co.uk/content/28/27179.html">reports</A>
that if you type "go to hell" into 
<A HREF="http://www.google.com/">Google</A>, the first result is
"Microsoft Corporation, Where do you want to go today?"  
Number two is <A HREF="http://hell.com">hell.com</A>, "which seems to
be a very weird site we do not understand".

<P> Hell.com has now regained the #1 slot, and Microsoft is not to be
seen.  Cynics might wonder if Bill Gates did a backroom deal with
Google to get their entry off the results.


<a name="nottag"></a>
<p> <hr> <p> 
<!--====================================================================-->

<center><h3><font color="maroon">Not The Answer Gang</font></h3></center>

<p> <hr> <p> 
<!--======================================================================-->
<p>

<H3 align="left"><img src="../gx/dennis/qbubble.gif" 
	height="50" width="60" alt="(?) " border="0"
	>Kitchen chemistry</H3>


<p align="right"><strong>Answered By Ben Okopnik, Iron, Dan Wilder and Heather Stern
<p></strong></p>

<P>
<BLOCKQUOTE><STRONG>
What hapens when bicarb is added to a week acid?
</STRONG></BLOCKQUOTE> 

<P>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Ben]

Takes two weeks to come down off the trip, dude. It's like, unreal.

<P> (Yes, I just got back from California. Why do you ask?)

<P>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Iron]

Like totally, dude. 

<P>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Dan]

Same thing as when it is added to a month acid, but faster.

<P>
<IMG SRC="../gx/dennis/bbub.gif" ALT="(!)"
	HEIGHT="28" WIDTH="50" BORDER="0"
	> [Heather]

You wanted "Cecil Adams, The Straight Dope" -- he does stuff like that.
"Women's Day" could probably answer you too.

<P> We're "The Linux Gazette Answer Gang" -- we answer Linux questions, not
chemistry matters.

<P> Please advise us where you encountered the "linux-questions-only@ssc.com" address
and what implied to you that it addressed general questions.  We're
trying to chase down old references and get them updated.




<a name="other"></a>
<p> <hr> <p> 
<!--====================================================================-->

<center><h3><font color="maroon">In Other News...</font></h3></center>

<p> <hr> <p> 
<!--====================================================================-->

<H4>Women hurt when bullet hits computer</H4>

EVERETT, Washington -- A woman was injured in a drive-by shooting about 5:45
a.m. yesterday as she sat at the computer in her home in the 3400 block of
119th Place Southeast. A bullet hit her computer screen, causing glass to
shatter in her face, said Snohomish County Sheriff's Department spokeswoman Jan
Jorgensen.

<P> Police found seven rounds in the house, Jorgensen said.

<P> Although they did not give a motive, police said they do not believe the
shooting was random.

<P> Only the woman and her husband, who are both in their 40s, live at the
home, Jorgensen said.

<P> -- <A HREF="http://seattlepi.nwsource.com/local/89150_filler30.shtml">
http://seattlepi.nwsource.com/local/89150_filler30.shtml</A> 




<HR> <!-- ************************************************************** -->

<P> Happy Linuxing!

<P> Mike ("Iron") Orr<br>
Editor, <A HREF="http://www.linuxgazette.com/"><i>Linux Gazette</i></A>, <A
HREF="mailto:gazette@ssc.com">gazette@ssc.com</a>
<BR CLEAR="all">









<!-- *** BEGIN copyright *** -->
<hr>
<CENTER><SMALL><STRONG>

Copyright &copy; 2002, Mike ("Iron") Orr.
Copying license <A HREF="../copying.html">http://www.linuxgazette.com/copying.html</A><BR> 
Published in Issue 83 of <i>Linux Gazette</i>, October 2002</H5>
</STRONG></SMALL></CENTER>
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