Linux Gazette... making Linux just a little more fun!
Copyright © 1996-98 Specialized Systems Consultants, Inc.
_________________________________________________________________
Welcome to Linux Gazette! (tm)
_________________________________________________________________
Published by:
Linux Journal
_________________________________________________________________
Sponsored by:
InfoMagic
S.u.S.E.
Red Hat
Our sponsors make financial contributions toward the costs of
publishing Linux Gazette. If you would like to become a sponsor of LG,
e-mail us at sponsor@ssc.com.
Linux Gazette is a non-commercial, freely available publication and
will remain that way. Show your support by using the products of our
sponsors and publisher. To subscribe to Linux Journal, click here.
_________________________________________________________________
Table of Contents
March 1998 Issue #26
_________________________________________________________________
* The Front Page
* The MailBag
+ Article Ideas
+ Help Wanted
+ General Mail
* More 2 Cent Tips
+ Apache SSL extensions...
+ Locate
+ Re: Printing Problems
+ Re: LG25, Netscape on the Desktop
+ Re: Linux and VAX 3400 and 3300
+ Binary File Access with dd
+ Follow up to find 2c-tip
+ ispell & Pine 3.96
+ XVSCAN: Combining different parts together
+ 2c-tip: Netscape on the Desktop
+ Linux and Win95
+ My $0.02 tip: Graphical su
+ Easter Eggs in Netscape
+ Core Dumps
* News Bytes
+ News in General
+ Software Announcements
* The Answer Guy, by James T. Dennis
+ Can't Telnet to Red Hat 5.0 Server
+ Use the Source, Luke!
+ 'ifconfig' to Troubleshoot Dropped Ethernet Packets?
+ Cthugha
+ xdm Login doesn't!
* Clueless At The Prompt, by Mike List
* EMACSulation, by Eric Marsden
* Graphics Muse, by Michael J. Hammel
* Linux on a Kapok 7200, by Alessandro Usseglio Viretta
* Low Cost Macintosh-Linux Networking at Home, by Dr. Richard L.
Dubs
* New Release Reviews, by Larry Ayers
+ Tcd and Gtcd
* Setting up Your In-Home (or In-Office) Network, by Tom Kunz
* The Yorick Programming Language, by Cary O'Brien
* The Back Page
+ About This Month's Authors
+ Not Linux
The Answer Guy
The Weekend Mechanic will return.
_________________________________________________________________
The Whole Damn Thing 1 (text)
The Whole Damn Thing 2 (HTML)
are files containing the entire issue: one in text format, one in
HTML. They are provided strictly as a way to save the contents as one
file for later printing in the format of your choice; there is no
guarantee of working links in the HTML version.
_________________________________________________________________
Got any great ideas for improvements? Send your comments, criticisms,
suggestions and ideas.
_________________________________________________________________
This page written and maintained by the Editor of Linux Gazette,
gazette@ssc.com
"Linux Gazette...making Linux just a little more fun!"
_________________________________________________________________
The Mailbag!
Write the Gazette at gazette@ssc.com
Contents:
* Help Wanted -- Article Ideas
* General Mail
_________________________________________________________________
Help Wanted -- Article Ideas
_________________________________________________________________
Date: Sun, 01 Feb 1998 21:43:23 -0800
From: Bradley Akey, bakey@slip.net
Subject: Creative Labs SB-16 & Sony CDU76E-S
I am attempting to install RedHAt Linux ver 4.2 from a Sony CDU-76E-S
CD-ROm connected to a Sound Blaster 16 via an IDE interface at base io
0x1E8, IRQ 15. Waht is the correct boot parameter to get this CD-ROM
to function properley
_________________________________________________________________
Date: Tue, 3 Feb 1998 08:25:32 -0500 (EST)
From: Michael Stutz, stutz@dsl.org
Subject: Help Wanted: recording audio data
Is there any way to read and save the data that is currently being
played by the soundcard, regardless of the sound source?
(There is a program in alpha which does this called paudio, at
http://web.syr.edu/~jdimpson/proj/. It creates a readable /proc/audio
-- but I haven't yet gotten it to work with the OSS-compatible driver
produced by the Linux Ultrasound Project which I use.)
Michael Stutz
_________________________________________________________________
Date: Mon, 09 Feb 1998 14:18:49 -0500
From: Todd Blake, tbb@enterprise.aacc.cc.md.us
Subject: Help Wanted
I like most people am the only person to use my linux system at home.
What I'd like to do is when my system is done booting to have me
automatically login as my main user account(not as root though) on one
virtual console(the first) and leave all other consoles and virtual
consoles alone, so that someone telnetting in will get a login prompt
like normal, just that I won't. I'd still like the other vc's have
login's for others to login and other reasons. I've tried just putting
/bin/sh in /etc/inittab and that didn't work, and I'm stumped. Does
anyone have any ideas on this?
Todd Blake
_________________________________________________________________
Date: Mon, 09 Feb 1998 17:47:08 -0600
From: peter smith, psmith@computek.net
Subject: Problems with Linux through Wingate Socks
I'm having a few problems accessing the internet through Wingate v2.0
on my Windows95 machine using my Linux Redhat 4.2 installation. I've
had this SOCKS server set-up for quite some time on my internet
dial-out machine and have previously had no problems accessing the
internet through this server via my second machine's installation of
Windows95 or even WindowsNT. The problem is directly related to DNS
lookups. If I access a domain-name from my Linux machine that seems to
get redirected, I will receive an error that the DNS address does not
exist. For instance, if I attempt to open the web page
http://www.kernel.org (which gets redirected to
http://linux.kernel.org) my browser (Netscape v4.04 for Linux 2.0*
i386 rpm) reports a DNS error. However if I instead attempt to open
the redirected web page http://linux.kernel.org my browser will open
it ok, without error. I'm baffled by this behavior and have tried a
number of different things! I can provide more detailed information if
needed. Thanks in advance to any who try to help! ;)
I love Linux Gazette and have a great time browsing all the cool
suggestions and tips! Keep up the ideas and info!
PeterS
_________________________________________________________________
Date: Mon, 09 Feb 1998 19:04:42 -0500
From: Melmac88, smegan@erols.com
Subject: Shadow passwords
Can someone do a clear explanation on how to set up a shadow password
file, and exactly how it works? I've seen this recommended for
security purposes in many books and articles, but there never seems to
be an explanation on how to do this.
_________________________________________________________________
Date: Wed, 09 Dec 1998 04:38:06 -0900
From: David Lev, dlev@polarnet.com
Subject: my dual pentium
My name is David Lev, I have a problem with my second CPU.
I am currently using a Caldera OpenLinux Standard with Kernel
(2.0.29-2). After I install the system I try to enable the 2 CPU and
my computer FREEZE or I loss my DeskTop and it takes for ever to do
one process. but with one CPU the computer work fine no problems at
all. I ask for your help. If you can help me also on how to enable 2
modems and run them as one.
My computer content:
ATX Dual Motherboard - GA-586DX with SCSI on board
Adaptec 7880
CPU - 2x 233MMX Pentium
128M RAM EDO
2x 3.1G HDD - W.D - IDE
2x 8X CD-ROM - IDE
2x 56K Modem
ESS Sound card
_________________________________________________________________
Date: Sat, 14 Feb 1998 15:00:34 EST
From: Andreas M. Weiner, HGuAWeiner@aol.com
Subject: Linux and AMD K6 Processor - any Problems?
This is my hardware configuration. Support answered that there would
be problems with using the K6 with Linux; for instance a crash.
What dou you know about this problem ?
Could you send me a some informations to solve this problem ?
Are there Kernel patches available ?
I'm looking forward of getting the answers from you
Andreas M. Weiner
_________________________________________________________________
Date: Sun, 15 Feb 1998 10:26:36 -0800
From: David, elvii@writeme.com
Subject: X without a Mouse?
Been searching around the net and ldp, and can't seem to find anything
on this one. Trying to be able to use X WITHOUT a mouse. Yes, I know,
it works bets with a mouse, but I'd like to be able to get at least
limited x funcationality without it. Any help is greatly appreciated,
and being waited. Also, is there any was to do mouse emulation without
a mouse? I found a program that translated ps/2 to a standard serial
mouse, for before x supported ps/2, i assume... anyone know if a
program has been written to allow the keypad to do mouse, ie,
translate keypad input to /dev/mouse? Thanks for your time, hoping
some kind linux guru's out there can help. :)
David
_________________________________________________________________
Date: Mon, 16 Feb 1998 21:59:04 -0700
From: Todd Jamison, jamisont@littoneos.com
Subject: Help with Sound Card
I currently am running RedHat 5.0 on a Pentium 150 W/48 MB Ram. I =
cannot get my ESS ES1868 plug and play sound card to work. I am very =
new to linux and am still learning. If anyone can help me i would =
really appreciate it.
Todd
_________________________________________________________________
Date: Tue, 17 Feb 1998 16:41:49 -0600
From: John Gorman, John.H.Gorman@MCI.Com
Subject: HP4 & font
I just installed a HP LaserJet 4L on RedHat 4.2 Intel and when I print
postscript (from emacs, etc), it prints at about a size 24 font. How
to I set my font where I want it.
Thanks
John Gorman
_________________________________________________________________
Date: Fri, 20 Feb 1998 08:46:12 +0100
From: Jeroen Bulters, jbulters@scoutnet.nl
Subject: Changing XDM windows
Can I change the XDM login window/screen? I have a cool house logo so
i want to use it in my own Home Network. And at my school they want to
know to so. Is it possible. If yes, how? If no, WHY NOT.
Jeroen Bulters, The netherlands
_________________________________________________________________
Date: Tue, 17 Feb 1998 01:36:30 +0000
From: Mackenzie St. Louis, mstlouis@tiac.net
Subject: New Motherboards
A lot of motherboards have been coming out lately with built in
graphics and sound. Any plans to cover them. I just bought a TX-Pro-II
board with graphics and sound. However I think I will be returning it
since I can't get the sound to work. It has a SoundPro chip. Can not
also get XFree 3.3.1 to run properly. It will only come in 8 bit
320x200, even though the graphic chip is supposed to be AGP. If you
could point out where I can get some info. I would gladly write an
article for the Gazette in case any else comes across this same
problem. Please email me with any info or questions.
_________________________________________________________________
Date: Tue, 24 Feb 1998 16:28:09 -0800
From: chewey nougat, daiger@usc.edu
Subject: HELP-Installing Linux on a FAT32 Drive
I'm interested in installing linux on a machine I built recently, but
= when I installed Win95(b), I idiotically opted to format the drive
using = FAT32, which in a 95-only environment is great, but linux
can't read it = for greek.
I've looked around for utilities to effectively un-FAT32 the drive, =
which I will then partition with Partition Magic to use the freespace
as = a native ext2 partition, etc., but am having little luck.
Reformating is = a disheartening prospect I would rather not face, but
am fully prepared = to do so if I don't find any help here.
much thanks,
nate daiger
_________________________________________________________________
Date: Thu, 26 Feb 1998 13:47:06 -0500
From: Brian O. Bush, bbush@xtdl.com
Subject: question on motor control
Does anyone know how to interface and control two motors from a Linux
box? I am looking for a simple solution (in circuit at least).
Thanks,
Brian
_________________________________________________________________
Date: Fri, 27 Feb 98 14:16:13 -0500
From: Bill R. Williams, brw@ETSU.Edu
Subject: Wanting HELP!
First off: I can *not* believe I am the only one bitten by this.
In the process of getting a System installed I upgraded from the
original CD-ROM install of (Intel) RedHat 4.2 to the new RedHat 5.0
CD-ROM. One of the significant items on this system is the mars-nwe
Netware emulator.
Under the RedHat 4.2 with mars-nwe 0.98pl8-1 the mars package ran
fine, but logged copious errors about there being "too many
connections -- increase the number in config.h". But it ran, and I
*liked* the way it happily did Netware duties! (Especially the printer
part.)
The *new* RedHat 5.0 with mars-nwe 0.99pl2-1 offered some very
desirable abilities, not the least of which is the move of some items
(such as number of connections) to the run-time config file
(/etc/nwserv.conf under RedHat, probably nw.ini on other
distributions.) Now the bad news...
Of lesser, but still irritating, importance is the fact that the mars
package won't shutdown without some hard kills. This may be related to
the really important problem which is:
This new package spawns out nwconn processes with an empty parenthesis
as the last token instead of the USERID ('nwconn ... ()') until all
connection slots are eaten, and then, of course, will not recognize
any new attempts. Any users already logged into the nwserv(ice) are
Ok.
Since I am neither a Netware guru nor a mars guru I can only hazard a
guess, but since the nwconn(s) are children of the ncpserv daemon I
suspect that ncpserv is the source of the troubles.
I have tried every combination of parameter twiddling in the run-time
config file that can think of, but to no avail.
One thing I have noticed, the 2.0.32 linux kernel
/usr/src/linux/.config no longer has the 'CONFIG_IPX_INTERN' setting
(should be unset according to mars-nwe docs) which existed in 2.0.27.
This may or may not have anything to do with the problem. Checking the
kernel sources, it appears that the RedHat rpm of the 2.0.32 kernel
has the mars patches incorporated into the source.
Anyone who has solved this problem, please share the secret.
BTW: I attempted resolution through the RedHat Support system as a
registered RedHat customer, and if anybody wants a good laugh I'll be
happy to share the "circle of correspondence" from RedHat support. I
did learn from the attempt that no *human* at RedHat actually ever
sees the E-Mail to the support team or 'Bugs' team. (The "auto answer"
mechanism will get right back to you, though, and tell you not to
expect an answer.)
As I said, I can *not* believe I am the only one bitten by this,
because I've looked on the news groups and seen several posts with
"Mars and RedHat 5.0" in the Subject fields. These were all on the
French os.linux.... lists, and unfortunately I do not read French!
Sorry for the rambling on...
Bill R. Williams
_________________________________________________________________
Date: Sat, 7 Feb 1998 13:03:24 +0100 (CET)
From: Manfred Lemke, lema0019@FH-Karlsruhe.DE
Subject: Support for IBM Ethernet card?
I'm frantically searching for some kind of support for IBM's LAN
Adapter/A for Ethernet. Does any of you know of a driver in the Linux
Kernel that works?
Best regards and thanks in advance,
Manfred Lemke
_________________________________________________________________
General Mail
_________________________________________________________________
Date: Fri, 27 Feb 1998 00:09:33 +0100 (MET)
From: Radoslav Dejanovic, rdejanov@public.srce.
Subject: Linux Journalists International
Linux Journalists International is an effort to make a meeting point
for journalists who use Linux or simply write about it. It is also a
place where other journalists and other people can take a look what is
going on with Linux and media that supports it. There will be info
pages about magazines/media and journalists who use Linux and/or write
about Linux & related software.
I am editor in one croatian computer magazine (http://www.pcchip.hr)
and this is my effort to give the Linux community something that
lacks: popularity in media and a chance to boost media coverage of
Linux. The homepage is at http://www.purger.com/~rado/lji.html -
please take a look at it. LJ and LG are the strongest "Linux inside"
media :), so your support in this project is essential.
Rado
_________________________________________________________________
Date: Wed, 4 Feb 1998 10:02:08 -0500 (EST)
From: Paul Lussier, plussier@LanCity.COM
Subject: Retraction Re: Linux and routing
It was just called to my attention that this came across a little to
strongly and I'd like to clarify what I had previously written.
On Tue, 6 Jan 1998, I wrote:
Some words of caution. DO NOT HAVE YOUR LAN CONNECTED AT THE TIME
OF THE CABLE MODEM INSTALLATION!!!! [Comapany names removed], and
most of the other cable companies (we deal with them all here) will
refuse to connect a LAN to their broadband network. Simply remove
your hub or coax cable from view, and let them do what they need to
do, then connect everything else up after they leave.
This was probably a little of an overstatement. I know only of 1
company that has this as a policy, but have heard of people having
problems with some of the others. I have even recently been informed
of one company that is *quite* Linux friendly and will "encourage the
use of Linux as firewall/routers" as well as "allow and assist
individuals & companies to setup there own Web servers, either at
their permises or ours. We offer web hosting and will assist in
registering a domain name". So, I obviously made an improper, blanket
statement which does not represent the attitudes or policies of all
companies.
Some other interesting tidbits of information about cable modems
and cable companies:
1. Do not expect support for running a LAN over the cable modem
from the cable company. They don't want you to do it, they won't
help you do it.
2. Do not expect to put up a web server to be accessed by from the
internet. You are a client, not a server. This technology,though
fully capable of performing in this manner, is not being deployed
for use this way.
Again, this is a blanket statement that *does not* apply to all cable
companies. There is a good reason for those companies who do hold this
policy, and perhaps I should have gone into more detail. When you get
a cable modem from a cable company, *typically* you are agreeing to
lease the equipment from them under similar agreement as you rent the
TV set top box for cable television reception. The agreement typically
states that you are not allowed to run the cable to any other TV for
which you do not rent a box. The same goes for the cable modems. They
are agreeing to lease you 1 modem for 1 computer. Setting up a
firewall/proxy server to enable other systems access is exactly like
placing a diplexor on you TV set, and running the cable to another
television. That is a violation of the agreement, and is illegal,
immoral, and unethical; it's stealing. And again, I re-iterate, this
is not true for *all* companies. Check with your cable company, they
should be happy to explain their policies to you.
I don't really think you *should* expect to be able to do either of
these though, unless the cable company has provisions in place. You
are agreeing to connect one computer to their network as a client.
Anything more, you should expect to pay more, as they are providing
you with increased capabilities. Just like the phone company charges
more per added service (*69, caller ID, etc) so should the cable
companies. Personally, I think that average rate of US$40-$50 a month
for the equivalent of a T1 to my house is an awesome deal. If I want
more capability, I should expect and be willing to pay more.
Cable companies WILL shut you down for running a server of anykind
on your end of the network, and it can be *forever* :(
Again, I spoke without clarification. Obviously it depends upon the
policies of your local cable company. I know of 2 or 3 instances where
this has been the case. By stating the above, I was trying to warn of
the possible consequences of violating the contract with the cable
company. If the cable company specifies in the contract what you are
allowed to do and what you are not allowed to do, you should expect to
deal with the consequences of violating the agreement.
Spammers love cable/broadband networks. There have been several
cases where a broadband network customer has been used by spammers
and were subsequently shutdown for life by the cable company. What
happens is the person decides to connect their private LAN to the
cable modem but sets the firewall up incorrectly. Spammers search
cable/broadband networks for proxy servers/firewalls (Usually
Win95/NT) that allow incoming connections and then use that system
to spam the entire cable/broadband network making the spam appear
as if you sent it.
Spammers love any insecure system or network. Broadband Technology
though, for the first time has allowed people more extensive and
closer contact with other people on the internet. When you dial into
an ISP with a normal modem, it's a little more difficult for devious
minded people to take advantage of other users. But with cable modems,
you now have hundreds and/or thousands of people all on the same
private network, all with similars IP addresses, many of whom, now
leave their systems connected for much longer periods of time. This
makes it much easier for crackers, and other mischievous people, to
take advantage of anyone who isn't running a properly secured system.
Usually you will be given 1 warning by the cable company, but there
have been cases where none was given and the customer was
completely shut down.
I have heard of this happening on several occasions, where usually the
person was running an improperly configured firewall, and spammers
used their system to launch e-mail to thousands of people connected to
cable companies' private broadband networks. If I'm paying $40 or $50
a month for this service, I, as a paying customer do not want to
receive solicitous e-mail (spam) from some one else, especially if
they are on the same broadband network as I. I would complain to my
cable company about it and expect them to do something. It was these
exact circumstances that has led to several people having their cable
modems permanently removed.
Current modems are capable of transmitting at 10Mbs in both
directions, but are usually deployed throttled back to a trasmit
speed of 300Kbs and a recieve speed of 1.5Mbs. You want more
bandwidth, they'll be happy to charge you more money :)
Personally, I think this is very fair. The cable companies are
providing us with a service. We, as consumers, have to pay for this
service. Just like my electric bill, if I use a lot of electric
service, I pay a lot of money; or like the telephone company, if I
have more features or want a T1, I pay more money than if I only had a
normal telephone line. It's the same with cable modem technology, the
capability is there for 10Mbps bandwidth in both directions. The
technology is also there to regulate that flow. I expect the cable
companies to use that technology. If I want LAN speeds to my house, I
should expect to have to pay for it.
Again, I want to apologize for not clarifying my previous statements a
little more. Please check with your local cable company before you do
anything like connecting your private LAN to theirs. There are as many
different policies as there are cable companies, so make sure to
explicitly ask if what you want to do is permitted. This is a great
technology and has tremendous benefits. Playing by the rules that the
cable company has put in place will only help the technology spread.
By violating the rules, you run the risk of losing access to it, as
well as making it more difficult for the cable comapanies to contiue
selling this service. Like any other market driven product, if there's
no money in it, or it costs too much to implement, it will fall by the
wayside, and no one benefits. By not folling the rules, we as
customers can make it cost prohibitive for implementation, and
conversely, by following the rules, we create more market demand,
which in turn, continues pushing the technology forward, and everyone
benefits.
#include <std_disclaimer.h>
I don't pretend to know all the policies of all the cable companies. I
don't assume to speak for any of the,, nor do I tell them how to
operate. My opinions are my own, and no one else's. Dammit Jim, I am a
Unix sysadmin, not a sales rep :)
Please feel free to send me questions, comments, criticisms, etc.
Paul
_________________________________________________________________
Date: Thu, 5 Feb 1998 15:01:30 -0500
From: Jack Chaney, JAC14@chrysler.com
Subject: New Direction
I heard on the radio last night, an announcement that IBM has just
successfully masked, produced and tested their newest piece of
silicon. The processor is based on the PowerPC design and is reported
to run at 1000MHz. Knowing what I know about the PowerPC and its
various flavours, I think it would do to examine the idea of porting
Linux in a native coded version to this processor platform. The
pricing of this chip with a heavy duty operating environment could
give the Alpha a real run for its money.
The PowerPC (for those who don't know) is a RISC based processor with
three major operation blocks, each capable of independent operation.
This enables the instruction flow to become parallelized so as many as
three instructions can be done simultaneously, and because it is a
RISC processor the instructions have been optimised so most occur in
only one or two cycles. The other element of the design is to have an
extremely large cache memory on-board the processor to reduce fetch
time for instructions. To give an idea of the improvement in speed
realised by this method, a PowerPC emulates the Intel part by keeping
an interpreter block in the cache memory of the chip and interprets
the Intel object code at comparable speeds of the Intel parts. The
lure of creating a native Linux for this processor has crossed my mind
on a number of occasions prior to the IBM announcement, and now I hope
with encouragement this can move from fantasy to fact.
Jack Chaney
_________________________________________________________________
Date: Fri, 6 Feb 1998 08:50:00 -0500
From: Hampton, Mike, hamptom1@INDY.NAVY.MIL
Subject: Picking a nit
Maybe I should have called the subject of this "pet peeve" or
something like that. What I am writing about is a simple grammatical
error that I have seen many people make, but one that shouldn't appear
in the Gazette or any published effort and that is the incorrect use
of "it's" when the author should have used "its." An example is in the
following sentence from a recent issue:
"This was necessary in order for a *nix version to behave to
applications like it's counterparts so applications could run
everywhere."
If you take the "it's" and expand it, the sentence would read:
"This was necessary in order for a *nix version to behave to
applications like it is counterparts so applications could run
everywhere."
The sentence no longer makes sense. Authors should remember that
"it's" is a contraction of "it is." If they want a possessive of "it,"
they should use "its." I have also seen instances of authors using the
apostrophe-s when they intended to form a plural but made a possesive
instead (for example, using menu's, a possesive, instead of menus, the
proper plural form). Like I said before, these are very simple and
common errors, but ones which I feel can hurt the author's
credibility.
Before anybody gets too defensive, let me say that as an employee of a
major defense contractor, I have made the above error and have had it
pointed out to me. Maybe that's why it stands out so much when I see
it now.
Now I'll put down my pen and let others point out my errors.
Mike Hampton
_________________________________________________________________
Date: Fri, 06 Feb 1998 08:12:09 -0600
From: Tyree Gwyn, bounti@myriad.net
Subject: love your site!!
i very much enjoy the information found on LG!! even though i am
posting from a windows machine, i use linux(redhat 5.0) the majority
of the time. i just happen to be at work, at this time.
anyway, being a newbie to this whole linux scheme, i have used your
site, dejanews, oreilly books, and many howto's to get my system up to
my specs. linux is very exciting, and has alot of promise. please keep
up the good work.
Tyree
_________________________________________________________________
Date: Sun, 08 Feb 98 17:34:41 -0500
From: Leon C. Isaacson, lci2@global.co.za
Subject: Incomplete Book Reviews
In Linux Gazette 25, the review of "A Practical Guide to Linux" , by
Mark Sobell, fails to supply the publishers name, publication date,
and price. I enjoyed the review, but surely this information should be
included as a matter of course. Given your reviewers laudatory
comments, how or where can the rest of us hope to acquire this book?
Leon
(I agree. He should have included that information. Here's what I
know:
Publisher: Addison Wesley Longman, info@awl.com,
http://www.awl.com/
Price: $38.00 US
ISBN: 0-201-89549-B
-- Editor)
_________________________________________________________________
Date: Fri, 21 Nov 1997 18:59:53 -0500
From: Timothy D. Gray, timgray@lambdanet.com Subject: Getting Linux to
the public...
Has anyone noticed that when your friends see your neat-o Linux system
with the nice 17 inch monitor, high quality video card, and fast
computer that when they say, "Wow! that is nice, and you can do almost
anything on that!" you cringe with the fact that they are going to
want you to put it on their system? now mind you, I dont cringe on
sharing the best O/S on the planet, In fact I want everyone to use
Linux. It's just that almost all X windows software is written for
1024 X 768 or higher resolution video screens and that 99% of those
wanting to use Linux and X windows only have a 14" monitor that can
barely get past 640X480 at 256 colors. I tried several times to get
friends into Linux and X but to no avail because the software
developed for X is for those that have Gobs of money for good video
boards and humoungous monitors. It's not a limitation of Linux or X,
it that the software that is developed for these platforms are by
professionals or professional users that can afford that new 21 inch
monitor at the computer store. We as a group might want to see
software scaled back to the 640X480 crowd.. then Linux would take the
world by storm.. Until then It's going to be limited to us pioneers
and Scientists...
Tim Gray
_________________________________________________________________
Date: Wed, 25 Feb 1998 15:42:09 +0000
From: Jaime E. Villate,villate@fe.up.pt
Subject: uptime record
In Issue 25 (February 98) Sean Horan wrote about a Linux system that
ran continously for 274 days. Here is a quote from Bruce Perens
(president of Debian, works at Pixar) that I took from
http://www.debian.org
"I thought three months without a reboot was a big deal. When I
mentioned it to our developers, one of them showed me details about
his system. It was up for 458 days, and was halted to move it to
another floor. The network and disk device drivers had handled tens
of millions of interrupts in that time."
It would be interesting to know what the record is for other operating
systems older than Linux.
Jaime Villate, University of Porto, Portugal
http://www.fe.up.pt/~villate/
_________________________________________________________________
Published in Linux Gazette Issue 26, March 1998
_________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Next
This page written and maintained by the Editor of Linux Gazette,
gazette@ssc.com
Copyright © 1998 Specialized Systems Consultants, Inc.
"Linux Gazette...making Linux just a little more fun!"
_________________________________________________________________
More 2ў Tips!
Send Linux Tips and Tricks to gazette@ssc.com
_________________________________________________________________
Contents:
* Apache SSL extensions...
* Locate
* Re: Printing Problems
* Re: LG25, Netscape on the Desktop
* Re: Linux and VAX 3400 and 3300
* Binary File Access with dd
* Follow up to find 2c-tip
* ispell & Pine 3.96
* XVSCAN: Combining different parts together
* 2c-tip: Netscape on the Desktop
* Linux and Win95
* My $0.02 tip: Graphical su
* Easter Eggs in Netscape
* Core Dumps
_________________________________________________________________
Apache SSL extensions...
Date: Fri, 27 Feb 1998 15:49:41 -0800
From: Glenn D'mello, glenn@arbornet.org
From Frank: My problem is this one ... I've gone bananas in trying
to find a document that explains how to install, in a step by step
fashion, the Apache SSL "extensions" to one of my Apache WWW
Webservers (the performance increase is awesome) can you or anyone
that reads this help...
This is how I did it:
1. Get SSLeay 0.8.0 or later from
ftp://ftp.psy.uq.oz.au/pub/Crypto/SSL
2. Build and test and install it!
3. Get Apache 1.2.5 source
4. Get Apache SSLeay extensions from
ftp://ftp.ox.ac.uk/pub/crypto/SSL/apache_1.2.5+ssl_1.13.tar.gz
5. Unpack it in the apache-1.2.5 source directory and patch Apache as
per the README.
6. Configure and build it.
7. Read the docs before building (set your paths, etc, etc)
Worked the first time too! Hope this helps:
Glenn.
_________________________________________________________________
Locate
From: John Corey, <A HREF="mailto:norm@comanche.dyn.ml.org">
norm@comanche.dyn.ml.org</A>
One of my annoyances with the locate program have been that with it,
users can see files they have no access to otherwise. So, I have
deviced a little patch to the original sources to fix that, along with
a few other annoyances. It inherently does a few other things as well.
It will only list files that do currently exist (not just files that
existed when updatedb was last run). Also, it adds the option -l to
locate which simply performs a ls -l on the files returned.
To compile, get the sources from
ftp://prep.ai.mit.edu/pub/gnu/findutils-4.1.tar.gz . Extract that,
then apply the attached diff to it with: patch The only file modified
is locate.c, so you can skip the installation process if you already
have updatedb/locate installed, and just simply replace your existing
locate binary with the new one (keeping a backup of the original,
should anything evil happen).
Enjoy
_________________________________________________________________
Re: Printing Problems
Date: Wed, 04 Feb 1998 22:05:40 +0100
From: M.H.M. Verhoeven, leeuweri@stad.dsl.nl
Anyone that can help me. I'd love to hear it. I try running lpr,
but everytime I get no name for local machine. How do I set this
and/or what is the problem. -- Manish Oberoi
I had the same problems with printing (no name for local machine). You
should put a entry for your machine in /etc/hosts, and your problem is
solved. In my case, the name of my computer had changed, but
/etc/hosts still contained the old name for my machine.
Gertjan
_________________________________________________________________
Re: LG25, Netscape on the Desktop
Date: Thu, 05 Feb 1998 00:26:03 +0100
From: Soenke J. Peters, peters@on-line.de
I use a similar trick to start up the browser-/mail-/news-window from
three different buttons in my windowmanager's panel. For the
mail-window, you have to start the script with 'mailbox:' as the url
parameter, for the news-window simply use 'news:'. For urls beginning
different from the above, netscape opens the normal browser window.
Soenke J. Peters, Hamburg, Germany
_________________________________________________________________
RE: Linux and VAX 3400 and 3300
Date: Thu, 05 Feb 1998 10:11:00 -0700
From: James Gilb, p27451@email.sps.mot.com To:
dennis.j.smith@ArthurAndersen.com
I have just purchased a MicroVAX 3400 and 3300. I would like to put
Linux on these two systems. Can you provide any help in this
aspect.
I believe those are MIPS 3000 boxes, try the Linux VAX Port Homepage
at http://ucnet.canberra.edu.au/~mikal/vaxlinux/home.html and the
Linux/MIPS project at http://lena.fnet.fr/
My guess is that you will need to get your hands dirty on this one.
You could also try NetBSD, they may have a port now.
If they are not MIPS boxes, then you could have a real challenge on
you hands, but then isn't that half the fun of Linux?
James Gilb
_________________________________________________________________
Binary File Access with dd
Date: February 9, 1998
From: Leonard R Budney lbudney@fore.com
dd stands for Disk Dump. Or if it doesn't it should. The "main" use
for dd is to duplicate a floppy disk, bit for bit, to a file. You
probably used it to create boot disks when you installed Linux for the
first time, unless you used its much less functional cousin rawrite.
If you're sick of keeping boxes of floppies around, you can use dd in
reverse, and throw the floppy away. Depending on permissions, you
might have to do this as root.
dd if=/dev/fd0 of=quicken_install_disk_1.img bs=1440k
The if argument specifies an input file (which defaults to the
standard input). Naturally, the of argument names the output file
(which defaults to the standard output). Finally, the bs argument
tells dd what block size to use. Here we set the block size equal to
the size of a floppy disk, and let dd read one block of data.
The man page says that the purpose of dd is to "convert a file while
copying it." In English, that means that dd does not assume a file is
made of text! It doesn't look for carriage returns to delimit lines,
it doesn't stop reading at the first binary zero, nothing! This gives
us the power to read files exactly, byte for byte. It allows us to
read a fixed number of bytes, or physically to overwrite a file.
As just one example, consider /dev/random. That's a nifty Linux
innovation--a pseudo device that accumulates randomness. Would you
like to read 10 bytes of random data from /dev/random? It's a snap.
dd if=/dev/random of=/tmp/random.bin bs=1 count=10
Note that /dev/random provides binary data, so if we omit the of
argument then that data will probably trash our display. Alternately,
we could have omitted the of argument, but piped the output through
cat -v to escape any non-printable characters. In addition to the
arguments explained above, we use the count argument to specify the
number of blocks to read. In conjunction with a blocksize of 1,
count=10 tells dd to read exactly 10 bytes.
Here's a final example, for the paranoid. When you delete a file using
rm, you only delete the inode pointing to your data. The data is still
there, on the disk, waiting for somebody with a "Disk Doctor" utility
to resurrect and read. Does that bother you? Well, you should delete
your data, not just your file. Again, dd comes to the rescue. Normally
dd truncates its output file before writing. The argument conv=notrunc
overrides that behavior, and causes dd to write over any existing
data. The following shell script combines all of these ideas, and
wipes out your file by overwriting it five times with pseudorandom
data, and then deleting it.
#!/bin/sh
FILE=$1
SIZE=`ls -l $FILE | awk -- '{print \$5;}'`
{
for iteration in 1 2 3 4 5
do
dd if=/dev/urandom of=$FILE bs=${SIZE} count=1 conv=notrunc
sync
done
} && rm -f $FILE
Enjoy!
Len.
_________________________________________________________________
Follow-up to find 2c-tip
Date: Tue, 10 Feb 1998 19:20:44 +0000
From: Markus Pilzecker, mp@rhein-neckar.netsurf.de
in your December issue, one of the 2-cents about find had been:
A shorter and more efficient way of doing it uses backticks:
grep "string" `find . -type f`
Note however, that if the find matches a large number of files you
may exceed a command line buffer in the shell and cause it to
complain.
The solution to this is using xargs:
find <find_roots> <other_options> -print0 | xargs -0 grep <options>
. xargs only puts as much onto grep's [or whatever else's] command
line as fits without overflow. Only in the latter case will it start a
new instance of grep. The trick of the first proposal to add
``/dev/null'' to grep's command line to make it print the name of the
file in work is [mostly] superfluous then, since xargs [mostly] puts
more than one filename onto grep's command line.
The find option ``-print0'' and the xargs option ``-0'' work together
to assure correct handling of odd filenames.
Markus
_________________________________________________________________
ispell & Pine 3.96
Date: Fri, 13 Feb 1998 08:39:34 -0800 (PST)
From: Peter Struijk, peter@ssc.com
To use ispell in Pine, go into Pine SETUP (press S, then C), search
using WhereIs for "speller" (press W) and make sure the value set
there is "ispell". That will do it.
Peter
_________________________________________________________________
XVSCAN: Combining different parts together
Date: Sat, 13 Sep 1997 01:04:29 -0500
From: Earl Fryman, fryman@io.com
To: xvscanlist@tummy.com
Is it possible to combine two (or more) different parts from
different pages on same fig? For example, if I scan pages and want
to print transparencies from small part of the text enlarged. Now,
if the part 1 is at the end of a page and the part 2 is on the
following page, I have not been able to combine them on one single
fig (part 1 and below it part 2). How could I do that with xvscan?
If the parts are on the same page I have used cut, past and crop.
--
Juha Perkkio, juha.perkkio@mikkeliamk.fi
Yes it is posible. Load the first image and select the portion of the
image to cut. Press Alt-C (hold down Alt key and press C). Load the
second image and press Alt-V. A frame window the size of the cut in
the first image will appear. Position the frame where you want the
image to be pasted, then press Alt-V (again). This even works if the
two image are of different type (bmp, jpg, gif, etc.).
Earl Fryman
_________________________________________________________________
2c-tip: Netscape on the Desktop
Date: Sun, 15 Feb 1998 19:43:58 -0100
From: Victor-A. Bruessow, Christian.Bruessow@t-online.de
I'm using this little bash script to start Netscape:
#!/bin/sh
if [ $1 ] ; then
REMOTE_COMMAND="openURL($@,new-window)"
else
REMOTE_COMMAND="openBrowser"
fi
netscape -remote $REMOTE_COMMAND || netscape $@
I think it has some advantages over the script from Tim Hawes:
* no need to look for a lock file, which means:
* it even starts Netscape, if there is a stale lock file from a
crashed browser session :-)
* you can call it without any arguments, it doesn't matter if there
is a running Netscape or not ("openURL($@,new-window)" will cause
an error, if "$@" is empty, so I use "openBrowser" instead)
Christian
_________________________________________________________________
Linux and Win95
Date: Wed, 18 Feb 1998 14:55:22 +1300
From: Justin Lodge, justin.lodge@optimation.co.nz
Rexson Re: Your Question e-mail to Linux Gazette
Your big problem is that Win95 has probably helped itself to the
entire drive already - so there is no space left available to install
extra Linux partitions.
What you really should do first is to back up all the existing
partitions using a tape or a Zip or a Jaz drive. Let me guess you
don't have one of these..... if you can beg/borrow/steal one
temporarily and back everything up before you do anything that would
be good.
Maybe your D: partition doesn't hold much and you can transfer the
data to the C: drive where Win95 is installed - this will allow you to
re-use the D: partition for Linux.
Next - buy/beg/borrow/steal a recent copy of Red Hat for Linux (make
sure you get the book and the floppy disks that come with the CD) and
the Doctor Linux book.
Red Hat has a beginners book with it that explains a lot that you need
to know to install Linux and a set of excellent scripts that lead you
though the installation.
doctor linux has good beginners sections and more complex ones about
dual booting Win95 and Linux
I would recommend that you DO NOT try to make the machine dual boot -
it could cock-up the win95 installation but these articles will help
you understand the mechanics around this area. The HOWTO articles in
Doctor Linux are all available on the Internet if you don't want to
buy a book but having a hard copy to reference is much easier.
once you have re-located any useful data off the D: to the C: then use
the disk partitioning tool that comes with red hat to de-allocate the
D: partition and then create the root, usr, swap and home (and any
others) in this area. From memory I believe that the root partition
has to be in a primary partition but all the rest can be logical
partitions contained in a single "extended" partition.
This re-allocation of partitions is EXTREMELY dicey - make absolutely
sure you understand which partition is C: and which is D: IF you
de-allocate C by mistake then it is almost definitely un-recoverable
unless you have Norton for Win95 or something similar that can repair
the damage.
Create a boot diskette using red hat so that when you want to run
Linux you just plug it in and re-boot the machine - booting off the
floppy may seem awkward but it is much much faster than any version of
Windoze.
Any one else using the family using the machine will not have this
boot diskette and will not be able to see your partitions from Win95
and won't even know that Linux is there. This is how I keep my family
off my copy of Linux.
Justin
_________________________________________________________________
My $0.02 tip: Graphical su
Date: Wed, 18 Feb 1998 22:01:25 +0100 (CET)
From: Andreas Kostyrka, andreas@rainbow.studorg.tuwien.ac.at
Sometimes one want to do su but be able to use X11 programs like RH
control-panel. There are several ways to accomplish this: *) The hard
way: su - and copy&paste the xauth:
$ xauth list $DISPLAY # mark the output
$ su -
# xauth add <paste the above line>
# export DISPLAY=<display mentioned in the pasted line.)
*) The overkill net way:
$ ssh localhost -l root
This depends upon you haveing installed ssh (ftp.replay.com is the
site where one gets the crypto stuff for RH Linux in .rpms), and is
probably not that fast, as it uses a X11 proxy forwarding server.
*) The graphical (XDM) way, or the way to show off for your WinNT
friends:
$ Xnest :10 -query localhost &
:10 must be perhaps customized if it is already in use. localhost is
your xdm host. This should work if you use xdm for login. (==You have
a graphical login screen.)
Andreas Kostyrka
_________________________________________________________________
Easter Eggs in Netscape
Date: Wed, 18 Feb 1998 13:32:57 -0800 (PST)
From: Eric Geyer, corduroy@sfo.com
I saw the list of Easter Eggs in Netscape, and I have two more, both
much less useful than the ones you listed.
about:mozilla
On all the Unix netscapes I've seen, it changes the Netscape logo in
the upper right.
about:jzw
This will take you to Jamie Zawinski's homepage, and will change the
Netscape logo on Unix netscape except for version 4.
Just thought you would like to know...
Eric Geyer
_________________________________________________________________
Core Dumps
Date: Thu, 19 Feb 1998 13:56:51 PST
From: Marty Leisner, leisner@sdsp.mc.xerox.com
I was annoyed on Linux that file(1) couldn't tell what file dumped
core if a core dump was seen.
For a while, I was doing strings | head and guess at it by inspection.
But size will do the job:
: leisner@dw;size core
text data bss dec hex filename
45056 295036 0 340092 5307c core (core file invoked as minicom - dp
p2)
marty
_________________________________________________________________
Published in Linux Gazette Issue 26, March 1998
_________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
_________________________________________________________________
This page maintained by the Editor of Linux Gazette, gazette@ssc.com
Copyright © 1998 Specialized Systems Consultants, Inc.
"Linux Gazette...making Linux just a little more fun!"
_________________________________________________________________
News Bytes
Contents:
* News in General
* Software Announcements
_________________________________________________________________
News in General
_________________________________________________________________
April Linux Journal
The April issue of Linux Journal will be hitting the newsstands March
6. The focus of this issue is Workplace Solutions with articles on
Marketing Linux, WordPerfect 7, Satellite Remote Sensing, Linux in
Biomedical Labs and much more. Check out the Table of Contents.
_________________________________________________________________
Washington, DC Linux Users Group InstallFest
1 Feb 1998
On March 28, 1998, the Washington DC area Linux User Group (DC LUG)
will have its next Linux Installation Fest. Volunteer experts from
several local Linux user groups will assist computer users interested
in trying out Linux, the operating system that Byte Magazine, Wired,
PC Magazine and other industry publications agree is a significant
software phenomenon. Bring your PC and leave with Linux co-installed,
or just visit the demo room to see what Linux is all about.
Started as an exercise in Internet-based collaboration among hundreds
of software developers around the globe, Linux has acquired a
reputation for superior power and robustness, along with a relentless
pace of improvements, a combination rarely matched by the mainstream
software Unix and Windows NT industry.
Linux has attracted an estimated 3 to 15 million users, and also
garnered commercial support, evidenced by several shrinkwrap vendors
with shelf space in mass-market computer stores. Even though in most
cases an installation of Linux is a simple procedure, DC LUG will help
those who may have unusual configurations or simply some trepidations
about jumping in. Representatives from RedHat Software, one of Linux
vendors, will also attend and provide advice.
The InstallFest will be held at the Uniformed Services University of
the Health Sciences, the medical school at the Bethesda Naval Medical
complex, just inside the Beltway between Wisconsin and Connecticut
Avenues.
Doors open at 10 AM through 4 PM, Saturday 28 March 1998. See
http://www.tux.org/fest for details and a requested pre-registration
form.
For more information:
David Lesher, wb8foz@nrk.com, (301) 608-9775
Przemek Klosowski, przemek@tux.org, (301) 975-6249
_________________________________________________________________
Linux in the News
A new spot to get Linux news information is
http://www.eklektix.com/lwn/, and don't forget
http://www.linuxhq.com/.
Linux for Dummies by Jon "maddog" Hall and others and Linux for
Dummies Quick Reference by Phil Hughes are out from IDG books. Get
your copy today.
InfoWorld's 02/02/98 issue names Red Hat Linux 5.0 as it's OS of the
year for 1997. The article can be found on-line at
http://www.infoworld.com/cgi-bin/displayArchive.pl?/98/05/poy2a.dat.ht
m under the Operating Systems heading.
Red Hat's Press Release
_________________________________________________________________
Debian Year 2000 Compliance
1 Feb 1998
Debian's Y2K compliance statement is at
http://www.debian.org/news.html#19980104
For more information:
Bruce Perens, bruce@pixar.com
_________________________________________________________________
"open source" -- new term for libre software
10 Feb 1998
The Open Source Definitionby Bruce Perens
Goodbye, "free software"; hello, "open source" by Eric Raymond
For more information:
http://www.opensource.org/
_________________________________________________________________
Linux receives the Softwarove noviny "Product of the year" award
1 Feb 1998
Date: Mon, 9 Feb 1998 13:53:30 GMT
The Czech computer monthly "Softwarove noviny" awarded the Linux 2.0
operating system with its award "Product of the Year 1997". This award
is regularly (for the sixth time this year) assigned to the best
computer products available on the Czech market without any other
limitation. The "Product of the Year" award is strictly
non-commercial, no fee is paid and no application is put in. Among the
criteria is technical excellence, amount of innovation, price /
performance ratio as well as the amount of value added by the domestic
vendor. The award was granted to 18 products for the past year, among
them two operating systems.
Softwarove noviny (www.softnov.cz) is a prestigious Czech computer
monthly. Its name (with meaning Software News) is rather traditional
than descriptive: actually it is a generally oriented computer
magazine that focuses on software as well as hardware, networking and
other aspects of IT market. It is published in Czech language and
distributed in both Czech and Slovak Republics. The Softwarove noviny
reader?s group includes professional IT users, entrepreneurs and
managers. The Softwarove noviny is the only Czech computer monthly
prepared entirely from domestic sources without translated articles
from American or German industry press. Softwarove noviny magazine
publishes now 16,000 copies (total population of Czech Republic is 10
million), 85 % of which are paid (1/3 by subscribers). About 40 % of
the magazine are occupied by advertisements of both Czech and
worldwide IT companies. According the independent surveys from
November 1996, the Softwarovй noviny magazine is the most known IT
magazine in the Czech Republic.
The WWW page of Softwarove noviny is available at
http://www.softnov.cz/. The Czech Linux Users' Group has its WWW page
at http://www.linux.cz/czlug/.
For more information:
Jan "Yenya" Kasprzak, kas@informatics.muni.cz,
http://www.fi.muni.cz/~kas/
_________________________________________________________________
WWW: inofficial StarOffice 4.0 for Linux FAQ
16 Feb 1998
Michael Hoennig has collected some questions and answers into an
inofficial FAQ of Linux (and some UNIX-) specific topics of StarOffice
4.0. This FAQ in the German language can be found at:
http://www.on-line.de/~michael.hoennig/soffice4-linux-faq-49.html
This FAQ in an English version can be found at:
http://www.on-line.de/~michael.hoennig/soffice4-linux-faq-01.html
For more information:
Michael Hoennig, mhoennig@on-line.de
_________________________________________________________________
WANTED: Project LEAP: Linux-Equipped Astronauts Project
1 Feb 1998
17 Feb 1998
Recent articles on the International Space Station (ISS) have
mentioned that astronauts will be issued laptop computers running
MSWin95. Other reports have predicted disastrous trouble with the
station control software, because of poor engineering practices and
unrealistic schedules.
This situation creates a real opportunity for Linux. While we
(probably) can't help with the main station software, at least the
astronauts can be freed from Win95 crashes. Imagine the sound bites:
"At least our laptops don't crash all the time."
PEAL is a project to port the applications that the astronauts use to
run under Linux, so each astronaut has a choice of operating systems.
Many of them will continue using MSWin95, for a time, but if any
astronaut chooses Linux, the others will begin to pick it up, just as
happens on the ground.
Anyone who wants to take over the web page, design a project logo, set
up a mail reflector, create a newsgroup, become group leader, or
(almost forgot :-) port software, please write. We need to know what
codes the astronauts need ported, and where the sources are. The
project web page, for now, is:
http://www.cantrip.org/leap.html
For more information:
Nathan Myers, ncm@nospam.cantrip.org, http://www.cantrip.org/
_________________________________________________________________
[INLINE]
4th Annual Linux Expo, May 28-30th
February 17, 1998:
Linux is making waves in the news, and now is the opportunity for the
world to find out why. It's time to get ready for the largest
gathering of the best and brightest minds in the computer world. For
three business-centered and technology-packed days, May 28-30, the
fourth annual Linux Expo will take over Duke University in Durham,
North Carolina.
This year's Linux Expo is shaping up to be a can't-miss event. Visit
the record number of Expo exhibitors (there is still time for your
company to become involved) showing the latest in Linux-based
hardware, software, and service solutions. And stop in on the business
and technical discussions to hear talks by some of the most important
names in technology today.
Yes, Linus Torvalds will be there. And so will many others.
Technical track speakers include:
* *Eric Youngdale - Future Directions of Linux SCSI Development
* *Dirk H Hohndel - XSuSE -- adding more to the XFree86 offerings
* *Frank T. Kujawski - Setting Up Diskless Computers, Quickly!
* *Simon Horman - Creating Redundant Servers in Linux
* *Jacques Gelinas - LinuxConf
* *Alan Cox - "I don't care if space aliens ate my mouse" or Porting
Linux to the Apple Macintosh 68K
* *Mike Westall - ATM Device Driver Development in Linux
* *Jes Sorensen - Linux/HIPPI - Linux Joins Supoercomputing
Networking
* *Bruce Perens - The Computer Graphics of Pixar
* *Lars Wirzenius - Linux Anecdotes
* *Greg Badros - A Caching NFS Client for Linux
* *Eric S. Raymond - Homesteading the Noosphere: Custom and Property
Rights in the Free Software Community
* *David S. Miller - Optimizing the Cobalt Microserver
* *Miguel de Icaza - GNOME: The GNU Network Object Model Environment
* *Alex "Mr. Worf" Yuriev - Optimizing Network Performance
* *Peter J. Braam - The Linux 2.1 New VFS Interface
* *Steffen Seeger - KGI: Graphics and Games with the Kernel
* *Andreas Beck - LibGGI The next generation fully portable graphics
library
* *Jason McMullan - EvStack - Linux Console Design, Take II
* *Daryll Strauss - Linux helps create Titanic
* *Stephen C. Tweedie - Journalling the Linux Filesystem
* *Peter J. Braam - The Coda Distributed Filesystem on Linux
There will also be Tutorial Sessions featuring among others:
* *Peter J. Braam - Coda Demonstrations
* *Jakub Jelinek - Hacking the Linux Kernel
Business track speakers include:
* *Bruce Perens, Software in the Public Interest--Free Software
Licensing
* *Jon maddog Hall, Digital Equipment Corp.-- Linux Around the World
* *James Gray, S.u.S. E.-- A Cooperative Model for Linux
Certification
* *Tim Bird, Caldera, Inc.-- The COAS Project
For more information:
linux@linuxexpo.org http://www.linuxexpo.org/
_________________________________________________________________
WWW: linux for starters WWW-page
Fri, 20 Feb 1998 08:29:00 GMT
Here's Yet Another Page Concerning Linux For Starters. In case
anyone's interested... http://www.ping.be/leminator/leminator.htm
For more information:
Koen Janssens, trott@mail.dma.be
_________________________________________________________________
WANTED: OpenBIOS - Freeware x86 BIOS iniatitive
1 Feb 1998
Fri, 20 Feb 1998 08:42:53 GMT
Some discussion about the possibility of a freeware 'GNU' BIOS was
casually mentioned on the Linux kernel mailing list last week. Talk
about it escalated, and a mailing list was quickly formed. After a few
more days of ideas, it seems like a very good possibility and some
people just hell bent on getting started.
What we are looking for now are people with a high degree of knowledge
about the low-level workings of the x86 PC architecture, and real mode
programming experience. Please join the mailing list and offer what
help you can.
Also understand that many Linux people are involved with this, but the
purpose is a COMPLETE BIOS replacement for use with all Intel x86
OS's, not just some new boot loader.
To subscribe to the OpenBIOS Mailing list, write an email To:
openbios-request@linkscape.net Subject [leave blank!] subscribe [in
the body] It is a majordomo managed list. Feel free to use extended MD
commands as needed.
OpenBIOS web pages: (DO NOT expect to find much here yet! )
http://www.linkscape.net/openbios/
http://www.freiburg.linux.de/OpenBIOS/
For more information:
Dave Cinege
_________________________________________________________________
Linus Torvalds at next SVLUG meeting March 4th
1 Feb 1998
20 Feb 1998
March 4, 1998, Linus Torvalds will speak at the Silicon Valley Linux
Users Group (SVLUG) meeting. The meeting begins at 7pm.
This meeting will be held at our new location, the GateWay Conference
Center, Building J, ciscoSystems. The address for this conference
center is:
255 W. Tasman Drive
San Jose, CA 95134
Please enter through the front entrance of the building, and the
conference center will be to your left. There will be signs.
For more information:
Rob Walker, rob@svlug.org
http://www.svlug.org/
_________________________________________________________________
[gtk-list] Qt/KDE Netscape -- An estimate of Work!
1 Feb 1998
John McNulty wrote: I'm sure after Netscape's source code
announcement, a number of people (like me) must have wondered about
the possibility of a port to KDE and/or Qt. So I asked one of the
Netscape engineers for an opinion on this. Below is the answer I got.
* The GUI frontend is clearly seperated from the rest of the browser
by a well defined API (which all 3 frontends - MFC, Mac, Motif -
use).
* There are about 50 widgets ( ls *.c | wc -l) that are Netscape
specific, which'll have to be ported.
* The GUI itself is composed of around 160 C++ files, which
instantiate these widgets.
Depending on the number of people working on it, it could take
anywhere between 2 months to an year. Of course, stripped down
versions are possible in a shorter period of time.
So if anyone put there is thinking about this, you can use this as a
guideline to figure out how much work is involved.
--John
_________________________________________________________________
Software Announcements
_________________________________________________________________
ZINC Software
9 Feb 1998
Zinc's flagship product, Zinc Application Framework, is a very high-
quality C++ GUI API and interface builder which supports popular
desktop operating systems (Windows, Motif, DOS, ...) *and* which is
scalable to embedded platforms as well (in 1/10th the space of Windows
CE!).
Zinc has recently negotiated distribution agreements with popular
Linux vendors to include ZAF with their CD-ROM distribution. Zinc has
also been engaged by top embedded operating systems' vendors to
provide reference ports of ZAF for their embedded OS.
For more information:
Robert Bishop, rbishop@zinc.com
Zinc Software Incorporated, http://www.zinc.com/
_________________________________________________________________
EDA Software: Linux VHDL Simulator Sells Via Web
9 Feb 1998
Essex Junction, Vt. -- Despite considerable user interest, very few
Linux-based EDA tools have become available. One of the first is a new
Linux version of the Green Mountain Computing Systems VHDL compiler,
available for $169 via the World Wide Web.
Green Mountain currently offers a DOS-based VHDL simulator, and
Accolade Design Automation (Duvall, Wash.) sells a Windows-based
version of the same simulator. The new version 2 of the Green Mountain
VHDL compiler supports most, but not all, of the features of IEEE
1076-87 and 1993 VHDL.
The Linux version is a port of the DOS version and includes all the
same features, except for the user interface. Both versions come with
two simulation environments for batch or interactive simulation,
precompiled IEEE packages, an online VHDL tutorial, a Motorola HC11
microcontroller example model and free technical support via e-mail.
Scott Thibault, president of Green Mountain Computing Systems, said he
developed the Linux version because that freely distributed operating
system is becoming more important in universities, which have made up
Green Mountain's primary market. He said the Linux version is slightly
slower than the DOS version because of its support for multitasking.
Linux has gained a following because it's viewed as a stable, robust
operating system that gives PCs full Unix compatibility. Thus,
commonly used Unix utilities such as "make" are available. Linux also
has minimal memory requirements. The Green Mountain Linux VHDL
compiler can run in about 8 Mbytes of RAM. The simulator can be
ordered only by mail or over the Internet.
For more information:
Andy@Piziali.dv.org
http://together.net/~thibault
_________________________________________________________________
EAGLE LINUX M68K
for AMIGA, Atari, Mac 68k and all computers based on the Motorola
MC680x0 CPU is now available. The end user delivery starts the first
week of March. Linux is pre-available on CDR for press and magazines.
Distribution:
Eagle Computer Products GmbH,
S.u.S.E. GmbH
Update CDs will follow every 2-3 months. Planned versionen which will
come soon:
* Intel PC Linux
* PowerPC Linux
* DEC Alpha Linux
For more information:
Dragon Internet Design, Frank Rosendahl & Klaus-Peter Walter
linux@eagle-cp.com
_________________________________________________________________
Olicom Linux Token-Ring driver released
6 Feb 1998
Olicom is pleased to announce the release of a Linux Driver for
Olicom's high performance Token-Ring Adapters OC-3118 and OC-3137. The
driver is also compatible with the older OC-3136 adapter. The
combination of Olicom's Token-Ring adapters and new Linux drivers
provide superior performance in a Linux Token-Ring environment.
The driver has been tested with the (currently) latest version of the
2.0 kernel, 2.0.33. It will probably work with any 2.0 kernel, i.e.
all of the kernels used by the Linux distributions, but this has not
been tested and can not be guaranteed.
For the current development versions of Linux 2.1 the driver has been
tested with version 2.1.78. Changes to the development kernel are
occurring in rapid pace and compatibility can not be guaranteed.
The Olicom Linux driver is available from Olicom's WEB site
http://www.olicom.dk/ (Europe) or http://www.olicom.com/ (US).
Pre-compiled kernels with the driver builtin - based on Linux 2.0.33 -
for RedHat 4.2, RedHat 5.0 and other systems using the Linux 2.0.x
kernel, are available from
ftp://ftp.olicom.dk/pub/releases/Unix-Driver/Linux/unsupported/
For more information:
henrik_stoerner@olicom.dk
http://www.olicom.dk/ (Europe)
http://www.olicom.com/ (US)
_________________________________________________________________
GNU plotting utilities 2.0 released
6 Feb 1998
Release 2.0 of the GNU plotting utilities is now available at
ftp://ftp.gnu.org/pub/gnu/plotutils-2.0.tar.gz . It should soon be
available via ftp from the GNU mirror sites. A list of mirror sites is
appended below; please try them before you try ftp.gnu.org.
This is a major release. The centerpiece of the package is now
`libplot', a function library for 2-D device-independent graphics.
Libplot is installed as a DLL (dynamically linked library), on systems
that support DLL's. Libplot now supports Hewlett-Packard Graphics
Language (HP-GL and HP-GL/2) output, in addition to Postscript, xfig,
Tektronix, and X11 output. So HP LaserJet and other PCL 5 printers are
now supported.
The manual for the plotting utilities is now over 100 pages long. To
install and print the documentation, be sure that you have the current
release of the GNU texinfo package (v. 3.11) installed on your system.
You may retrieve it from ftp://ftp.gnu.org/pub/gnu/texinfo-3.11.tar.gz
.
For more information:
Mathematics Department, University of Arizona
Robert S. Maier, rsm@math.arizona.edu
_________________________________________________________________
Data Plotting Library DISLIN 6.3c
6 Feb 1998
DISLIN is a high-level and easy to use plotting library for displaying
data as curves, bar graphs, pie charts, 3D-colour plots, surfaces,
contours and maps. Several output formats are supported such as X11,
VGA, PostScript, CGM, HPGL, TIFF and Prescribe. The library contains
about 400 plotting and parameter setting routines and is available for
several C, Fortran 77 and Fortran 90 compilers.
Version 6.3c of DISLIN is now released for Linux. The supported
compilers are GCC, G77, Imagine F, NAGf90, Absoft f77 and Absoft f90.
Plotting extensions for the programming languages Perl 5.003 and
Python 1.5 are included.
All DISLIN distributions for Linux are free. DISLIN is available from
the DISLIN Home Page:
http://www.mpae.gwdg.de/dislin/dislin.html
and via FTP from the server:
ftp://ftp.gwdg.de/pub/grafik/dislin/
For more information:
Max-Planck-Institut fuer Aeronomie
Helmut Michels, michels@linax1.mpae.gwdg.de
_________________________________________________________________
ktalkd-0.4.1 - Enhanced talk daemon
6 Feb 1998
ktalkd is an enhanced talk daemon with answering machine for Unix
systems, designed to work under KDE, but can also work without it. It
is available at:
ftp://aurora.resi.insa-lyon.fr/pub/people/dfaure/linux/ktalkd-0.4.1.tg
z
ftp://ftp.kde.org/pub/kde/Incoming/ktalkd-0.4.1.tgz
Tested on Linux or BSD, with or without KDE.
For more information:
David Faure, david.faure@ifhamy.insa-lyon.fr
_________________________________________________________________
angela! 1.7 BETA - graph editor w/ Tcl/Tk interface
9 Feb 1998
angela! stands for:
A ngela is a
N atural
G raph
E ditor with
L ayout
A lgorithms
!
angela! is free of charge (GPL LICENSE)
It is intended to help the user creating simple graphs for courses,
technical diagrams or simply demonstrating what graph algorithms can
do.
The developpment platform is Linux 2.0.32 with glibc libraries as
there are provided with RedHat 5.0. Porting angela! to other systems
should not be difficult as it uses these Programs:
* Standard C compiler (no C++ code at this time)
* CWEB Version 3.4
* Tcl/Tk Version 8.0p2
* Tix 4.1
For binary distributions, only Tcl/Tk Version 8.0p2 and Tix 4.1 are
necessary. Contact your system administrator to help you installing
these tools (also used by other programs, so the disk space is not
wasted ;) )
The actual version is at this time under the following URL:
http://www.mpi-sb.mpg.de/~pabst/angela/
For more information:
Oliver Pabst, olpa@itm.uni-sb.de
University of Saarland, Computing Center, Germany.
_________________________________________________________________
Tsinvest, version 0.4, stock trading program released.
9 Feb 1998
The C sources to a stock trading program, tsinvest.tar.gz, version
0.4, are available at ftp://sunsite.unc.edu:/pub/Linux/Incoming/"> or
ftp://sunsite.unc.edu:/pub/Linux/apps/financial/investment/. The
sources are free for non-commercial use.
The program tsinvest is for quantitative financial analysis of equity
values. An optimal portfolio investment strategy for multiple equities
is computed. The program decides which of all available equities to
invest in at any single time, by calculating the instantaneous future
value of all equities, and using statistical estimation techniques to
estimate the accuracy of the calculated values. Entropic techniques
are used throughout. A tutorial is presented in the man(1) pages. A
companion equity market simulation program is included.
For more information:
John Conover, conover@netcom.com
_________________________________________________________________
Linux Logo 1.04 - shows system info with a linux logo
9 Feb 1998
linux_logo outputs a color ansi version of a penguin, accompanied by
system info gathered from proc. SUPPORTS Linux, SMP, Atari m68k, and
even some non-Linux OS's
USES [instructions included]:
* Have a boot-up penguin in userspace [avoid kernel bloat]
* Impress your friends with a fancy color penguin login/motd
* Have a "penguin" port on your computer
* Use your imagination!
WHERE TO GET LINUX_LOGO:
http://www.glue.umd.edu/~weave/vmwprod/linux_logo-1.04.tar.gz
http://sunsite.unc.edu/pub/Linux/Incoming/linux_logo-1.04.tar.gz -- at
first
http://sunsite.unc.edu/pub/Linux/logos/penguin/linux_logo-1.04.tar.gz
Check out other programs at http://www.glue.umd.edu/~weave/vmwprod
For more information:
Vince Weaver, weave@eng.umd.edu, http://www.glue.umd.edu/~weave/
_________________________________________________________________
xfpovray v1.3 - An X interface for POV-Ray raytracer
16 Feb 1998
I would like to present a new version (1.3) of my xforms interface to
the ray tracer POV-Ray. If you have ever used POV-Ray from the command
line, you might find this program useful. Check:
http://cspar.uah.edu/~mallozzir/
Source code is available in tgz, bzip2, and rpm formats.
For more information:
Robert S. Mallozzi, mallors@crazyhorse.msfc.nasa.gov
http://cspar.uah.edu/~mallozzir/
University of Alabama
_________________________________________________________________
Casio Digital Diary Backup/restore v2.2
17 Feb 1998
Casio Diary is a package that allows communication to the CASIO series
of hand-held organizers based on a protocol posted by Knut Radloff,
knut@krhh.hanse.de.
Version 2.2 has been tested on Linux2.x , Solaris2.x, sunos4.x. For
both the BOSS and ILLUMINATOR models and is released under the GPL.
It is provided as is i.e. jamal is not to be responsible for any
damages it causes to you, your CASIO or your environment.
Primary-site: http://sunsite.unc.edu/pub/Linux/apps/comm/
100kB casio22.tgz, 1kB casio.lsm Alternate-site:
ftp://ftp.cyberus.ca/pub/users/hadi/casio/casio22.tgz
For more information:
Jamal Hadi Salim, hadi@cyberus.ca
Ottawa, Canada
_________________________________________________________________
Telnet98 - updated telnet source distribution
18 Feb 1998
Telnet98 is a new release of the ubiquitous "telnet" utility, based on
the 1995 MIT telnet distribution from ftp.cray.com and
net-dist.mit.edu. Telnet98 adds some new features to the distribution
including new 'configure' based build and install scripts and support
for additional authentication and encryption types.
Telnet98 can be downloaded from
ftp://quasimodo.stanford.edu/pub/telnet/, and US/Canadian users can
find instructions there for downloading source with strong (128-bit)
encryption enabled.
For more information:
Thomas Wu, tjw@xenon.stanford.edu
Stanford University: Computer Science Department, CA USA
_________________________________________________________________
Subject: fetchmail-4.3.7 - mail retriever for POP and IMAP
18 Feb 1998
The 4.3.7 release of fetchmail is now available at the usual
locations, including http://earthspace.net/~esr/fetchmail/. Here are
the release
For more information:
Eric S. Raymond, esr@snark.thyrsus.com
Organization: Eric Conspiracy Secret Labs, http://earthspace.net/~esr
_________________________________________________________________
leap 1.1.9 - A free RDBMS
20 Feb 1998
LEAP is a free RDBMS (Relational Database Management System) that has
been used as an educational tool in Universities around the world to
aid students as they learn database theory. It allows relational
algebra expressions to be entered directly into the system, and the
results to be queried. It supports relational closure, so complete
expressions can be deeply nested. Examples are included from popular
database texts, including C.J.Date's "An introduction to database
systems".
LEAP is entirely free (it is distributed under the terms of the GNU
General Public License), and is very easy to install. All
distributions contain the full 'C' source code. Versions exist for all
Unix implementations, and Windoze 95/3.1/NT. Full documentation is
included in the distribution, and is available on the web. LEAP is in
active development (on a Linux 2.0 slackware system) by the author.
Full details, including links to the main ftp archives, are available
on the LEAP web page:
http://www.dogbert.demon.co.uk/leap.html
http://www.brookes.ac.uk/~e0190404/leap.html
Strictly speaking LEAP 1.1.9 is BETA software, but extensive testing
has shown no major problems.
For more information:
Richard Leyton, rleyton@acm.org
_________________________________________________________________
WMF - WebMailFolder 1.0.1 mail folder to html converter
20 Feb 1998
This tool is for converting mails to html and can be used for
mailinglist archive.
It can be found on: ftp://sunsite.unc.edu/incoming/Linux/ or
ftp://sunsite.unc.edu/pub/Linux/Incoming/ should be moved to
ftp://sunsite.unc.edu/pub/Linux/apps/www/converters/
ftp://ftp.lugs.ch/incoming should be moved to
ftp://ftp.lugs.ch/pub/linux/mail
For more details see the doc/ChangeLog or Norbert Kuemin, Swisscom,
Norbert.Kuemin@gd2.swissptt.ch
http://www.lugs.ch/LUGS_Members/norbert.kuemin/wmf.html
_________________________________________________________________
bash Book Released
27 Feb 1998
New Edition of the "Definitive Guide to bash" released--O'Reilly's
Learning the bash Shell By Cameron Newham & Bill Rosenblatt now covers
Version 2.0. This second edition covers all of the features of bash
Version 2.0, while still applying to bash Version 1.x. New features
include one-dimensional arrays, parameter expansion, and more
pattern-matching operations. In addition, bash 2.0 is POSIX.2
conformant. This updated edition covers new commands, security
improvements, additions to ReadLine, improved configuration and
installation, and an additional programming aid, the bash shell
debugger.
For more information:
O'Reilly & Associates, info@ora.com, http://www.oreilly.com/
_________________________________________________________________
Published in Linux Gazette Issue 26, March 1998
_________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
_________________________________________________________________
This page written and maintained by the Editor of Linux Gazette,
gazette@ssc.com
Copyright © 1998 Specialized Systems Consultants, Inc.
"Linux Gazette...making Linux just a little more fun!"
_________________________________________________________________
The Answer Guy
By James T. Dennis, answerguy@ssc.com
Starshine Technical Services, http://www.starshine.org/
_________________________________________________________________
Contents:
* Can't Telnet to Red Hat 5.0 Server
* Use the Source, Luke!
* 'ifconfig' to Troubleshoot Dropped Ethernet Packets?
* Cthugha
* xdm Login doesn't!
_________________________________________________________________
Can't Telnet to Red Hat 5.0 Server
From: Brad Lackey, lackeyb@holly.colostate.edu
I am trying to set up a LINUX web server for Colorado State =
University - CIS Dept. I have Red Hat 5.0 Installed with user accounts
= set up but I cannot telnet to the machine. I get the login prompt,
but = none of the user accounts that I have created seem to work,
including = root. they all give me "Login incorrect". I was wondering
how to fix = this validation problem...
Thanks, Brad
First I'll have to assume that you installed RH5 on a fresh x86
machine with no previous OS, and that you've just installed the
package from a CD and have yet to apply any upgrades or patches to it.
If that's the case -- fire up the old browser and go to Red Hat's
"Errata" pages at:
http://www.redhat.com/support/docs/rhl/rh50-errata-general.html
There are about 30 upgrade packages there -- including fixes for the
utils package (fixes 'vipw' command), and glibc (the core c libraries
which most of your other programs depend upon through the magic of
shared libraries).
I don't see a specific entry for the problem that you're describing --
and I haven't upgraded any systems to RH5 yet -- so I don't know if
this problem is generic.
A quick search of Yahoo!/Alta Vista and DejaNews doesn't show a match
to exactly this problem either -- but it does show that telnet to RH5
boxes is working for many people. (Many of the problems reported have
to do with long delays, caused by the "double-reverse lookup" that TCP
Wrappers uses to prevent most varieties of spoofing). So, given that
the search string "+red +hat +5 +telnet +login" didn't give us an easy
answer we'll have to do some troubleshooting.
Let's start with some questions:
Does your syslog (/var/log/messages or /var/log/security) tell you
anything?
Have you run pw5conv to enable shadow passwords?
If you run 'vipw' ('vi' the /etc/passwd file) do the password hashes
appear there?
Have you installed a different PAM (pluggable authentication modules)
or modified its configuration (any of the files under /etc/pam.d/)?
I didn't see a new PAM RPM up at the site listed above -- though
things like the initscripts package and the glibc package might help.
If these questions don't help you find the problem and resolve it I'd
suggest that you grab a Red Hat 4.2 or a S.u.S.E., Debian or other
distribution and install that. If you use Red Hat 4.2 you'll want to
fetch all the upgrades for that -- and you might be able to install
specific RH5 rpms (including the glibc which *should* co-exist cleanly
with the libc 5.x that most (almost all) Linux distributions prior to
RH5 rely on).
As a support volunteer I find Red Hat's decision to push the release
of "Hurricane" out the door at the end of last year to be abominable.
I suggested to them that they do a 4.5 first -- and wait until about
March of this year for a 5.0 (hoping that glibc would be better
understood, that PAM would move much closer to 1.0, and that the 2.2
kernel *might* ship by then).*
*** Please note: I don't have any "inside" hints as to when any of
these event will occur. I don't know how long it will take to go from
the 2.1.8x kernels through the inevitable 2.1.99.x flurry and get to
2.2. I read the kernel mailing list and cross my fingers like everyone
else. Obviously Red Hat Inc (the company) and Caldera, and Yggdrasil,
and many other organizations and individuals can help. If I were a
programmer I might be able to help more.
However, I was sure that 5.0 was too soon -- and the 34 Mb of upgrades
and patches that were available as of last November needed to be
released on CD to save the 'net a bunch of bandwidth. (I occasionally
cut these and similar new stuff onto CD's using my ISDN line and my
CD-R and give them away. I'm hoping to give one or two away at
tonight's SVLUG (Silicon Valley Linux User's Group) meeting where
we'll be hearing from Bruce Perens of the Debian project, and Eris S.
Raymond, whose paper on the "Crystal Cathedral" was cited as a key
part of Netscape's decision to release their sources)).
I'd like to see Red Hat adopt a subscription model, where I can get
monthly update of their "updates" and "contrib" mirrors for about
$10/month. (I suppose it doesn't *have* to be Red Hat to do this,
anyone with a CD-R and a reasonable trickle feed from the 'net could
do it. Though the economies of scale don't work until we get a few
hundred subscribers).
Heck, if there's enough interest I'll do it.
In any event, I hope one of these methods works.
At the risk of starting serious flame wars and raising questions about
my "loyalty to the cause" (which cause we're not sure) I'd also
suggest that you look at the OpenBSD (and FreeBSD and NetBSD)
distributions if you don't have a specific reason for picking Linux
for this application.
Linux is the most popular of the free Unix' -- but it's not the only
one -- and it's not necessarily the best for all applications.
OpenBSD, in particular, seems to be very well suited to multi-user
"student use" and "computer lab" use. This is because Theo de Raadt
and his team have found and corrected a large number of buffer
overflows and other vulnerabilities in the sources for FreeBSD and
NetBSD (and probably in the sources of many Linux utilities as well).
Obviously this depends quite a bit on your intended applications.
However, if I was setting up a general use shell account system for a
school lab, an ISP, or a USENIX "terminal room" I'd probably suggest
OpenBSD.
For personal workstations I think Linux holds the edge in performance
and applications availability.
--Jim
_________________________________________________________________
Use the Source, Luke!
From: SuatChoo Lua, suatchoo@yahoo.com
Here there something that maybe you can answer me. From where i can
get the information about Linux File system,memory managemant,and
scheduling algorithm. Thank you!
coco
In many ways I'm not the best person to answer this question. Remember
that I am not a coder -- and I haven't contributed any programming to
the Linux kernel (which I'm sure we all appreciate). However, I've
read a bit of it -- and will offer some opinions.
If you want deep information about -- technical details -- about Linux
filesystem, memory management, and scheduling internals than the
obvious thing to do is to read the sources.
/usr/src/linux/kernel/sched.c is about 1700 lines long (about 80
pages). There are about 30 .c files under /usr/src/linux/fs (the
filesystems directory) -- and about 160 .c files under that whole
tree. Linux supports many different filesystems -- although the one
that is considered to be "native" to Linux is the ext2fs.
A variant of this filesystem has been adopted by the FSF for their
ongoing HURD project (which is a microkernel OS for which rms and the
Free Software Foundation developed gcc, GNU emacs, and most of the
applications and utilities that make Linux possible).
The code for ext2fs is about 5000 lines. Probably the simplest
filesystem that ships with Linux is the Minix compatible one. Minix is
a simple microkernel operating system written by Andrew S. Tanenbaum
for inclusion with (and publication in) his text book on "Operating
Systems: Design and Implmentation." That book is one of the seminal
works on the topic -- and has probably been studied by every major
contributor to Linux.
The memory management code is in /usr/src/linux/mm. It probably shows
off the greatest innovations in the Linux kernel. The aggressive
strategies here allow a Linux kernel to operate within a pretty modest
footprint despite the "freeping creaturism" that some of its
detractors lament.
Where to begin:
* I'd start by reading Tanenbaum's book (there's a second edition
where he's joined by Albert S. Woodhull). Just read the first half
to get all the key concepts. The latter half of the book are the
sources for Minix; which don't relate to Linux.
* I'd then pick up a copy of the The Linux Kernel Hacker's Guide by
Micheal K. Johnson (should be at any good LDP -- Linux
Documentation Project -- mirror site).
* Then grab a copy of The Linux Kernel by David A. Rusling and LINUX
Kernel Internals by Michael Beck et al. (This last one is
published by Addison Wesley -- the others are available online --
and published/printed in various editions of _The_Linux_Bible_,
_Dr._Linux_, etc).
After you've read some of those the kernel sources will hopefully make
sense. Keep in mind that many of these things are still changing in
the form of patches and in the newer 2.1.x kernels. For example there
is a "evolution scheduler" which allows you to experiment with
different scheduling algorithms for your Linux system. You can learn
quite a bit about current Linux limitations by perusing Kurt Huwig's
collection of "unofficial" Linux patches at
http://linuxhq.sigkill.org/ or http://www.huwig.de if you'd like to
read them in the original German. These include several experimental
shedulers and memory management tweaks (like one that search for
duplicated pages and aliases them to one another on the fly).
I hope you find all those interesting and informative.
--Jim
_________________________________________________________________
'ifconfig' to Troubleshoot Dropped Ethernet Packets? Uh-Unhg!
From: Chris Oliphant, Chris.Oliphant@nextel.com
I have a HP Vectra XM2 4/100i computer with an onboard PCnet/32
ethernet chip running Red Hat Linux 4.0, kernal version 2.0.18. I
currently am having problems communicating over the ethernet
connection for the last three days. I want to use IFCONFIG to
troubleshooting the problem, but don't understand how to use the
command's output. My problems are excessive receive packets being
dropped and excessive transmit errors. I am able to ping the onboard
chip, and the port connect is good with other systems connected to it.
But when I connect my Linux system to the port, I have problems.
Please advise. Thanks for any assistance you may provide. --Chris
Oliphant
'ifconfig' is the "interface configuration" utility. It isn't a
troubleshooting tool. I'd usually 'ping', 'tcpdump' and 'netcat'* or
'kermit'* for troubleshooting this sort of problem.
* netcat is at ftp.avian.org (It is a little "swiss army knife" for
TCP/UDP -- providing a simple facility for scripted TCP
connections and transfers).
* kermit (C-Kermit) is at kermit.columbia.edu (Aside from being a
venerable file transfer protocol and serial communications
packages, C-Kermit is also a telnet/rlogin client -- offering file
transfers, scripting, debugging, and log-to-file features over TCP
connections).
Based on your question here's a few standard support questions to echo
back:
"for the last three days"? What happened then or before then? Did
the link work fine before then? Did you upgrade your kernel? Change
drivers? Add a new video card? Did this kernel/driver/module ever
work acceptably with this ethernet card? With this system's mixture
of other components? With a similar (so-called "identical") system?
Excessive errors on an ethernet line suggests the following sorts of
problems:
1. high collision rates -- Are there other boxes on your LAN segment
that might be utilizing an excessive amount of the bandwidth? How
many systems are on this segment? What applications are they
running (particularly network intensive)?
As an example if you put a few xterminals or diskless workstation
on a network and they fetch all of their X resources, binaries and
libraries over the wire (rather than tftp to a local RAM disk for
example) then you can flood an unswitched ethernet segment in no
time.
2. hardware problems with your card or someone else's (on the same
network segment) --
It is possible that some ether card on your segment is broken and
"chattering" (generating spurious signals which corrupt the data
frames (network layer "packets") from other cards. This is likely
to show symptoms across the entire segment (all the machines will
be affected). It is also possible that any particular card is
damaged. It is also possible for the problem to be in a particular
wire (are you using 10BaseT, coax/thin net, or (heaven forbid!)
thicknet?), or even a particular port on one of your hubs
(repeater, concentrator, whatever the "term du jour" for that
thingie-me-bob is). It could be as simple as "someone kinked the
wire by running it over with their chair wheel."
A good way to test for this is to get an ethernet "cross over"
cable (sort of a "null modem" for 10BaseT) and plug it between the
problem system and a known good one. This bypasses all the
intervening components to help isolate the problem.
(Basic troubleshooting 101: identify all components, eliminate as
many as possible for testing, continue simplifying the
configuration -- and possibly the tests -- until something works,
re-add components back until failure. That isolates the problem.)
3. bad driver or configuration -- If this has never worked under
Linux (or under the specific kernel your working with) you should
boot under some other OS and use whatever diagnostic utilities HP
provides. If those work and Linux still fails it suggests a
software configuration or driver problem. If you had an older
kernel that did work without a problem, try booting with it and
running your tests -- it's always possible that the card is broken
in someway that only shows up under conditions that don't occur
from DOS or Win '95. It's also possible that something in your
kernel is broken.
Naturally you'll also want to try a 2.0.33 or 2.0.34 kernel to see
if that helps.
As I've pointed out -- you need to do basic troubleshooting in
situations like this. You also want to ask yourself: "Have I provided
enough information for anyone (short of a psychic) to answer this
question?"
--Jim
_________________________________________________________________
Cthugha
From: kim angel, angelk@cadvision.com
Could you please tell me when Cthungha will be available for Win95?
Thanks!
Kim Angel
Sorry. Can't be much help there. I presume you mean Cthugha (no 'n')
which would be the audio/video amusement (turn your $3K multi-media
system into a $40 "discoteque" light).
Hmm....I detect a tad of dissatisfaction with the product!
I've never run it. I have a lack of interest in the class of software.
I had to look it up in the LSM (software map) to remember what it was
-- since I mis-remembered it as a "game").
I have no idea if or when it would be available for Win '95 -- or even
why anyone would port it. However, I'd contact the author/maintainer
(should find his/her/their name(s) in the man pages or docs).
What I am seeking is a program that is capable of applying digitized
animation choreographed to audio sequences. Could you help me with
this?
I'm the "Linux Answer Guy" (or, to be more specific and a little less
pretentious, the "Linux Gazette Answer Guy").
It appears that Cthugha *is* just what you want -- for Linux. I'm not
the "Windows '95 Answer Guy." A role which I probably would be wholly
inadequate at since I don't run it on any of my systems and I don't
like what little of it I've had to run.
Despite this I can offer you a pretty simple piece of advice:
Ask the author.
Another possibility is that you could try the port yourself. I'm not
sure what the licensing of Cthugha and its sources is -- but it's
probably GPL. That license lets you port it to any OS or platform you
like -- or pay anyone else to perform the port to your specs.
If you should find that the port to native Windows API's is too
difficult you could try DESQview/X (which offers X Windows API's over
DOS) or you could try OpenNT (from Softway Systems at
www.softway.com). OpenNT offers reasonably complete Unix API's -- and
some X Windows if I heard correctly -- and runs under NT. I have also
heard of several developers tools that purport to compile Unix/X
Windows code into native MS Windows API's. However I don't have any
experience with them, nor any personal interest in them.
-- Jim
_________________________________________________________________
xdm Login doesn't!
From: Cesar Augusto Kant Grossmann, ckant@fazenda.gov.
I run my Linux Box in the "graphics mode" (changing inittab
accordling) = bu I can't login as normal user. When I try to login as
normal user, the = screen flickers like a logout in the X, and the
login screen comes back.
This is also referred to as "using 'xdm'" (X Display Manager) which
provides a GUI login to X.
You don't mention what sort of system you have (which distribution
what architecture/platform, what packages you've installed or updated,
etc). You also don't mention whether you can login via a text mode
console (VC/VT) or via telnet or a serial line.
If you can, the problem is likely to be a mismatch between your 'xdm'
binary and the authentication model/settings that you have for your
other 'login' modes.
This is one area where the FreeBSD crowd definitely had a better
model. Under Linux you can use the old-fashioned (traditional -- and
insecure) authentication mode where the hashes of your passwords are
stored in the /etc/passwd. Alternatively you can install or enable
some variation of the "shadow" suite. This removes the password hashes
from the /etc/passwd file and stores them in a different file -- one
which is only accessible to privileged (SUID) programs -- and not
readable by normal users.
The purpose of all that is to make the system more resistant to
dictionary and cryptanalytic (brute force or otherwise) attacks. In
other words using the 'shadow' options is more secure than allowing
normal users to just snarf the hashes up, and copy them to a machine
running 'crack'.
The problem is that there are many programs that authenticate users
under Unix/Linux. In addition to login there's xdm, ftpd, xlock,
vlock, screen's lock feature, popd, imapd, the passwd command etc. In
FreeBSD they modified the libraries -- and ensured that all the
programs were linked against the same shared library. This hides the
details -- because the library calls that "getpwent()" (get password
file entries) automatigically merge the passwd hash from the shadow
file (called /etc/pwdb.master? or somethine like that -- in FreeBSD)
if that file exists and is readable.
Thus unprivileged files on a shadow enabled get pw entries with an
"obscured" password field (usually just a "x") while privileged (SUID)
program get a merged one that's suitable for comparison to a properly
crypted/hashed password as provided by an alleged user.
The other advantage to the FreeBSD method is that changing the hashing
algorithm (from the traditional 56-bit DES on a string of zeros -- to
a MD5 sum) is relatively easy -- only has to be supported in one place
(the shared libraries) and doesn't require that all the other programs
be changed. (Another feature of the FreeBSD password/account
management libraries is that they support dbm hashes of the account
names -- meaning that *huge* lists of accounts are possible without
suffering a "linear" increase in login/authentication response times)
For now Linux has three different, and partially incompatible
account/authentication schemes:
* Traditional /etc/passwd files
* Shadow suite (still with flat text files)
* PAM and libpwdb (dbm files and modular authentication model).
The frustrating thing is that these can all work together do some
degrees -- a pwdb system maintains a set of text flatfiles that are
sync'd to the dbm/hash tables (these hashes are the indexed/search
type -- as opposed to the cryptographic variety that I referred to
earlier -- like 56-DES and MD5).
Although Red Hat has shipped their last 2 or three releases with PAM
-- it isn't quite all there yet. The most recent version of PAM is
about 0.63 (beta). However -- if you installed a recent Red Hat Linux
(4.2 or 5.0 with patches) you should be able to use its xdm and all of
their stock utils without trouble.
If you compiled your own 'xdm' or fetched it from somewhere you should
consider recompiling it -- but looking for options that relate to
"shadow" support.
What seems to happen? Where I can find more informations about these?
A FAQ or something like...
I'd start by reading the Shadow HOWTO. I'd also suggest a web search
on PAM (pluggable authentication modules): Here's some URL's I have
for them:
* Andrew Morgan's Page: http://www.kernel.org/pub/linux/libs/pam/
* The Linux-PAM System Administrators' Guide:
http://www.math.muni.cz/linux/Linux-PAM/html/pam.html
* PAM - Pluggable Authentication:
http://www.redhat.com/linux-info/pam/
* PAM specs -- OSF RFC 86.0:
http://sysadm.sorosis.ro/devel/pam/rfc86.0.txt
It's a good idea to read about PAM since several other Unix flavors
are also moving towards it (currently appearing in Solaris and HP-UX,
at least).
Sorry for my bad English, but I think it's better than your
Portuguese...
Undoubtedly your English is better than my Portugese -- or even my
French (I've never studied the former and only had a couple of high
school years of the latter). --Jim
_________________________________________________________________
Copyright © 1998, James T. Dennis
Published in Linux Gazette Issue 26 March 1998
_________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
"Linux Gazette...making Linux just a little more fun!"
_________________________________________________________________
Clueless at the Prompt
By Mike List, troll@net-link.net
_________________________________________________________________
[INLINE]
Welcome to installment 6 of Clueless at the Prompt,
Here's this month's account of the triumphs, trials and tribulations
that I caused myself or encountered since the last time, and a couple
tips that may come in handy and increase your understanding of linux.
_________________________________________________________________
*Splitvt and Screen:
Last month, I suggested splitvt as a substitute for virtual consoles
when using a serial terminal. I still recommend splitvt since you can
work in two separate windows that are in sight of each other- cut and
paste with gpm is a snap for scavenging previously written scripts
or.... But several people wrote to tell me about screen, which is an
even better substitute for virtual consoles when using that dumb
terminal. I'm still working on making screen work fluidly, Alt-F* took
a little getting used to at first. Instead of the A-F* combination you
use the C-a* keys to open a new window. There are some other features
that I have only read about, the only difference between screen and
virtual consoles is that each new screen is already logged on.
Like I said, I'm not familiar with all of screen's features, but to
use it, basically you type:
screen progname
and your screen session is started in VT0. To add more VTs you can
use:
Ctrl-a c
and to change from one screen to another:
Ctrl-a 0-9
and you can change from screen to screen, depending on how many you
have opened. Note that the screens are numbered 0-9 rather than 1-10,
the only clumsy feature of this program, IMHO.
_________________________________________________________________
*Back to basics:
Some friends of mine, the nefarious UGD folks have a page "User Guide
Dog"which details many, if not most of the usual commands that a new
user might find useful but not clearly documented. I don't have to
tell you that man pages can be pretty hostile to a gnubee (ever wonder
what that picture was?), but if you check them out after using the
programs to do the things you most commonly need to do, you will most
likely achieve enlightenment - the information is suddenly much more
clear. The UGD Project is shaping up as a good vehicle for this
journey, if you can take the ride. Bring along your sense of humor,
one of the guys is a Canadian from out on the tundra ; ).
_________________________________________________________________
*Some stuff you may not hear anywhere else (so basic they forgot to tell
you):
Here's some stuff you probably already know about, if you've been into
Linux (or other unices)for a while.
*
Filename Completion
: If you aren't an enthusiastic typist, you'll find this of value.
Just type enough of the filename to make it unique, then hit
tab
it will complete the filename so you can get on with your life and
file manipulation.Play with this feature, if you haven't typed
enough of the name to be unique, it will sit and stare at you, try
another character or two.Likewise, if you specified the wrong
directory,you'll get nada.
*
Quick cd
: Another keystroke saving apparatus is:
..
and its close relative
.
The details for a quick cd areas follows: as you may be already aware,
the dots represent your current directory(single dot) and parent
directory (double dot).By CDing to
..
you will be magically transported to the parent directory, ie from
/usr/bin to /usr.You can use:
cd -
to return to the previous directory, and to go up two or more levels:
../../and so on
will work. The single dot is not as useful in terms of cd, but it does
have its use. If you are in a directory that's not in your path,
or dont have
.
in your path statement, you must give a path to run an executable
file. This is easily accomplished by typing:
./execuname
which will give the relative pathname, allowing it to be found and
run. There are a few good reasons why using the single dot in your
path statement isn't a good idea, suffice to say, if you'd like
more info on that subject, you should read up on system security.
*
GPM
: This has been so basic to my linux experience that I would be
crippled without it, in fact once when I flubbed an installation
and didn't have it running, it became my first priority to correct
that little oversight. The mere fact that the non unix OS seem not
to have this is reason to upgrade to Linux, although I found a dos
program that allows a similar use of the mouse on simtelnet. In a
related matter, if you dual boot(most home boxes, I'd imagine)you
might find yourself using
ls -aF
when you actually meant to type
dir
or
cp
when what you wanted was
copy
you can create batch files(like shell scripts) named for your favorite
unix commands, using your favorite switches. Not as cool as dosemu
or just plain staying in Linux, but ya gotta do what ya gotta do.
_________________________________________________________________
*Errata:
No I don't really do "make dev" when I make a kernel (maybe I could
blame it on my keyboard)make dep is what I meant.
_________________________________________________________________
If you have a subject that you would like to see covered or have any
corrections, comments or flames let me know, and I'll look into the
matter. troll@net-link.net
See you next month!
_________________________________________________________________
Copyright © 1998, Mike List
Published in Issue 26 of Linux Gazette, March 1998
_________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
_________________________________________________________________
"Linux Gazette...making Linux just a little more fun!"
_________________________________________________________________
EMACSulation
by Eric Marsden
_________________________________________________________________
This column is devoted to making the best use of Emacs, text editor
extraordinaire. Each issue I plan to present an Emacs extension
which can improve your productivity, make the sun shine more
brightly and the grass greener.
Internet-ready!
You've probably heard the hype about ``Internet-ready'' operating
systems where you can access the Internet with a click of your mouse.
Well, users of the customizable Emacs user interface have had the Net
only a keypress away since as early as 1989!
Emacs has built-in networking capability, which it uses for connecting
to news or SMTP servers and for web browsing. To illustrate its use,
here is a bit of code which opens a TCP connection to port 13 of your
local machine to request the current time :
;; usage: M-x display-date
(defun display-date ()
(interactive)
(let ((stream (open-network-stream "DAYTIME" nil "localhost" "daytime"))
)
(set-process-filter stream 'my-process-filter))
(defun my-process-filter (proc string)
(message "Current date is %s" (substring string 0 -1)))
This code --which assumes you're running inetd-- should display
something like the format of date in the minibuffer. The rich set of
primitives and the integrated error management provided by Emacs make
it easy to program useful utilities; consider how many lines of code
would have been required to provide the equivalent functionality in C.
Ange-ftp
Ange-ftp is a package by Andy Norman which allows Emacs to see the
entire Internet as a virtual filesystem. It adds remote editing
capability by mapping requests for remote files to FTP commands. For
example, if you ask Emacs to open a file named
/marsden@ondine.cict.fr:~/.emacs
then ange-ftp will spawn an FTP process, connect to the host
salines.cict.fr as user marsden, CWD to my home directory, GET my
Emacs initialization file and display the file as if it were on your
local filesystem. If ange-ftp needs a password it will read one from
the minibuffer. If you make changes to the file and save it, it will
be PUT back to the server for you. You can even copy files from one
remote machine to another by typing M-x copy-file RET
/user1@host1:/path/to/file1 RET /user2@host2:/path/file2 ; ange-ftp
looks after opening two ftp connections for you.
Ange-ftp comes pre-installed with Emacs (XEmacs features efs, a
complete rewrite by the same author). The only customization you might
need to make is to configure a gateway, if you don't have direct
Internet access. You can use ~/.netrc to configure default logins for
oft used hosts in the traditional way (and even passwords if you're
foolhardy).
Perhaps the most elegant feature of ange-ftp is its seamless
integration with Emacs; the only visible change it introduces is the
extended filename syntax. Filename completion (by pressing TAB in the
minibuffer) is available on remote hosts in the same way as on your
local machine. Ange-ftp works well with Dired, the directory editor,
allowing you to browse though distant machines, operate on several
remote files at once, etc. It also works with bookmarks, so you can
memorize an interesting spot on your favorite ftp server, and jump
back to the same spot next week with ease. Take a typical usage: ask
Emacs to open the following directory (with C-x C-f or from the Files
menubar) :
/anonymous@ftp.kernel.org:/pub/linux/kernel/
You will be presented with a directory listing many different releases
of Linux kernels (if you have a line like default login anonymous
password user@site in ~/.netrc then ange-ftp can infer the anonymous@
for you automatically). Type C-x r m to bookmark the location. There's
more on bookmarks in Jesper Pedersen's article in issue 7 of the Linux
Gazette.
Web browsing
Emacs-w3 (also referred to by some as Gnuscape) is a web browser
written by William Perry in Emacs Lisp. It is fairly sophisticated in
certain respects, having been the first production browser to support
cascading style sheets. It understands tables, and can display images
inline under XEmacs, or by invoking external viewers when hosted by
GNU Emacs. Its author notes that Emacs-w3 is yet another reason never
to leave the comfort of the One True Editor, but to me it serves more
as a reminder of the deficiencies of Emacs Lisp : it is slow, and has
a tendency to block while waiting on a slow link (unfortunately Emacs
is not multi-threaded, though you can set the variable
url-be-asynchronous to t to reduce this annoyance). If you want to try
it out get the latest version from the betas directory, which has many
improvements over the version distributed on most Linux CDROMs.
browse-url is an nifty Emacs extension which can dispatch references
to URLs to Mozilla or to Emacs-w3. It does this by using Netscape's
remote invocation protocol, which as a side note even works when
you're running the browser on a distant machine (the implementation
uses the X11 inter-application communication protocol). Emacs features
its own remote control mechanism which lets you send commands to a
running Emacs (even on another machine), called gnuserv/emacsclient,
which I might talk about another time.
Recent versions of Emacs are set up to use browse-url in mail and news
reading modes. URLs should be highlighted when you pass the mouse over
them, and you can click on them with the middle mouse button to invoke
your favorite browser. Here's how you can set up browse-url to use
Mozilla when you're running X11 and Emacs-w3 otherwise :
(if (eq window-system 'x)
(setq browse-url-browser-function 'browse-url-netscape
browse-url-new-window-p t)
(setq browse-url-browser-function 'browse-url-w3))
Another more indirect use of browse-url is WebJump by Neil W. Van
Dyke. This Emacs plugin provides a programmable hotlist of interesting
web sites with which to feed your browser. Perhaps its most
interesting feature is the ability to send a query to Internet search
engines such as AltaVista and Yahoo! without having to load the first
page of ads, but it also includes features for dispatching searches to
FAQ and RFC archives, to the online Webster or Thesaurus, or to bring
up an appropriate page of the Java API. Naturally (this is Emacs) you
can extend it to include your own favorite sites. You might find
yourself using it more than your browser's bookmarks.
Files at your Fingertips
ffap is a powerful package which extends the find-file command (the
one which prompts for a file name in the minibuffer, normally bound to
C-x C-f). It searches the text around the cursor position for
something which might represent a filename -- a file in the current
directory, a C #included file, a newsgroup reference, an ange-ftp
style reference to a file on a remote machine or an URL -- and prompts
you either to open that file, or to send the URL to a browser (via
browse-url). Once experiencing this you quickly get sick of typing
filenames into the minibuffer, and may find yourself inserting
``hyperlinks'' in strategic places in your files to save typing. ffap
is distributed with both Emacs and XEmacs; I bind it to the F3 key as
follows :
(autoload 'find-file-at-point "ffap" nil t)
(define-key global-map [(f3)] 'find-file-at-point)
or if you prefer you can simply override the traditional find-file by
saying
(autoload 'find-file-at-point "ffap" nil t)
(define-key global-map [(control x) (control f)] 'find-file-at-point)
ffap is pretty good at determining interesting filenames; it even
knows how to recognize RFC names, and from which server they may be
obtained. It goes to the trouble of pinging remote machines to
determine whether they are alive, and can naturally be extended to
recognize personal types of filename references. To conclude on
filename shortcuts, you might enjoy Noah Friedman's fff (Fast File
Finder) which helps you find files hidden somewhere deep in
inode-space by querying your locate database (part of the GNU
findutils).
Feedback
Several people wrote to me with comments on last month's article on
jka-compr. Chistopher B. Browne told me he prefers crypt++, which
provides on-the-fly decryption and encryption as well as automatic
compression and decompression. Whereas jka-compr trusts the filename
extension, crypt++ reads the first few bytes of the file to determine
its type. The package also has functions for dealing with DOS-style
linefeeds which you might find useful if you have to exchange files
with other operating systems, although you could just as well say
(standard-display-ascii 13 ""), which simply hides those ^M
characters. Crypt++ is not a standard part of Emacs (it's not included
in the GNU Emacs distribution, though it is bundled with XEmacs). I
haven't tested its cryptographic capabilities, because
<POLITICS>
As a French citizen I am prohibited from using any form of
encryption. In France encryption requires authorization from the
President, which is accorded only to large military companies and
to financial institutions (and then only if the keys are held in
escrow). These laws are one of the reasons holding back the
incorporation of kernel-level support for encryption in Linux.
Before accusing France of being backward, please consider the fact
that countries such as Iran, China and Russia impose similar
restrictions on the freedom of their citizens.
</POLITICS>
If you're using the latest version of XEmacs (20.3 stable as of this
writing), the suggestion I make last month for enabling jka-compr
won't work. The XEmacs maintainers have decided that the behaviour of
your editor shouldn't be modified by loading an extension module, but
by calling an appropriate initialization function. The correct way of
enabling jka-compr is to say (toggle-auto-compression 1 t). Sorry
'bout that, folks.
Next time ...
In the next issue I'll review ediff, a powerful interface to diff and
patch. Don't hesitate to contact me at <emarsden@mail.dotcom.fr> with
comments, corrections or suggestions (what's your favorite
couldn't-do-without Emacs extension package?). C-u 1000 M-x hail-emacs
!
PS : Emacs isn't in any way limited to Linux, since implementations
exist for many other operating systems. However, as one of the leading
bits of open-source software, one of the most powerful, complex and
customizable, I feel it has its place in the Linux Gazette.
_________________________________________________________________
Copyright © 1998, Eric Marsden
Published in Issue 26 of Linux Gazette, March 1998
_________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
_________________________________________________________________
"Linux Gazette...making Linux just a little more fun!"
_________________________________________________________________
Welcome to the Graphics Muse
Set your browser as wide as you'd like now. I've fixed the Muse to
expand to fill the aviailable space!
© 1998 by mjh
______________________________________________________________________
Button Bar muse:
1. v; to become absorbed in thought
2. n; [ fr. Any of the nine sister goddesses of learning and the arts
in Greek Mythology ]: a source of inspiration
W elcome to the Graphics Muse! Why a "muse"? Well, except for the
sisters aspect, the above definitions are pretty much the way I'd
describe my own interest in computer graphics: it keeps me deep in
thought and it is a daily source of inspiration.
[Graphics Mews][WebWonderings][Musings] [Resources]
T his column is dedicated to the use, creation, distribution, and
discussion of computer graphics tools for Linux systems.
Not much to say this month. I've been very busy working on some
things for Linux Journal and a few other projects. I did manager to
get the reviews done that I had promised last month. Well, 2 out of 3
of them. Thats better than I usually do.
In this months column I'll be covering the following:
* XeoMenu, a Java based menuing program
* an update on X server support for 3D cards and the X Input
Extension
* VRWave, a VRML browser for Linux
Graphics Mews Disclaimer: Before I get too far into this I
should note that any of the news items I post in this section are just
that - news. Either I happened to run across them via some mailing
list I was on, via some Usenet newsgroup, or via email from someone.
I'm not necessarily endorsing these products (some of which may be
commercial), I'm just letting you know I'd heard about them in the
past month.
indent
XFPovray 1.3
Robert Mallozzi announces a new version (1.3) of his XForms interface
to the ray tracer POV-Ray. If you have ever used POV-Ray from the
command line, you might find this program useful. Check
http://cspar.uah.edu/~mallozzir/
Source code is available in tgz, bzip2, and rpm formats.
Robert S. Mallozzi
University of Alabama
http://cspar.uah.edu/~mallozzir/ indent
XMRM 2.0 (Alpha release)
The Institute of Computer Graphics at Vienna University of Technology,
Austria, announce the release of XMRM 2.0alpha
XMRM (multi resolution morphing for X) is an image morphing program
written for XWindows. A special feature of this program, which is not
found in other morphing packages, is the ability to control the
morphing speed of details in relation to the morphing speed of big
features.
Check out the XMRM homepage:
http://www.cg.tuwien.ac.at/research/ca/mrm/
For a few animated GIFs visit the Online manual:
http://www.cg.tuwien.ac.at/~xmrm/
For download got to:
ftp://ftp.cg.tuwien.ac.at/pub/linux/xmrm/
Greetings, The XMRM-Team <xmrm@cg.tuwien.ac.at>
[INLINE] [INLINE]
FREETYPE 1.0 The FREE TrueType Font Engine
Copyright (C) 1996-1998 The FreeType Development Team
The FreeType engine is a free and portable TrueType font rendering
engine, available in ANSI C and Pascal source code. It has been
developed to provide TrueType support to a great variety of
platforms and environments.
Notice that FreeType is a library. It is not a font server for
your preferred environment, even though it has been designed to be
the basis of many high-level libraries, tools and font servers.
It's a clean-room implementation that is not derived from the
original TrueType engine developed by Apple and Microsoft, though
it matches it regarding rendering quality. To our knowledge, it's
the only royalty-free complete TrueType engine available.
For more information, please visit the Freetype web site at:
http://www.physiol.med.tu-muenchen.de
/~robert/freetype.html
Thats its. Not much in the way of announcments this month. I had a
few more, but lost them pasting them into my XPostitPlus program.
Thats the first time its crashed in that manner - where I lost the
data. Bummer.
[INLINE]
Did You Know?
...there is a OpenGL widget for GTK? Take a look at
ftp://ftp.gimp.org/pub/gtk/contrib/glgtk-demo.971104.tgz.
Q and A
Q: How do you use anti-aliasing with POV-Ray? Do higher values
cause more anti-aliasing?
A: Ron Parker responded on the IRTC-L discussion list: Whenever
POV-Ray detects a sufficient change, the threshold, in colour from one
pixel to it's neighbour, it will calculate the in-between color pixels
by shooting multiple rays into the scene, rather than just one, to
determine the colour. The higher the "+A" number is (from 0 to 1),
the more rays will be shot into the scene, and the smaller a
difference in colour from one pixel to the next will be needed to
cause the anti-aliasing to be brought into effect. Anti-aliasing is
triggered when the threshold between two pixels is reached. The number
of rays is controlled by +R, and the "spread" is controlled by +J.
Setting +A0.1 will trigger on smaller color differences than +A0.3, so
it actually anti-aliases more than higher values of +A. All this is
the description for +AM=1. Adaptive supersampling (+AM=2) works
somewhat differently.
For more information, see section 6.2.5.4 of the POV documentation.
Ron Parker * parkerr@mail.fwi.com * http://www2.fwi.com/~parkerr
Q: I took an image to a printer today who requested that I bring back
the image when I have increased the resolution from 72 pixels/inch to
300 pixels /inch. I cant locate how to do this with the GIMP. Any
pointers?
A: You can scale the image, but that will decrease the quality of
the image. The best way to deal with images you plan to print is to
plan to create them using the correct resolution. For example, if you
want an 8.5" by 11" image at 300pixels/inch:
width: 8.5*300 = 2550 pixels
height: 11*300 = 3300 pixels
So you need to start with an image window that is 2550x3300 and work
from there. Keep in mind - doing this sort of image manipulation
(with such large image sizes) is better suited to:
1. faster CPU's.
2. tons of memory
3. lots of disk space
As to "can I convert from 72 to 300 pixels from my original image":
yes, use the scale option (image->scale) and set the correct size.
But remember - scaling up will reduce image quality, especially going
from 72dpi to 300dpi.
[INLINE]
Reader Mail
An unnamed reader sent the following information:
I've recently written 3 Perl scripts which help to distribute the task
of rendering with povray between several CPU's. One script is for
SMP (multiple processor) machines. It will break an image into
halves and start a separate process for each. This utilizes both
CPU's in a dual processor machine, and nearly halves the rendering
time. The other two scripts work together to utilize multiple
machines on a network. The server script tells each client script
how much of an image to render (also sending the .pov file and any
necessary files to each client).
These scripts were created using Perl 5.004, Linux 2.0.32, and
POVRay 3.0. I'd be honored if you would like to include a link
from your excellent graphics site to my page at
http://www.frozenwave.com/~hixson/projects.html.
'Muse: I really need to update the LGH and UGU pages. Anyway, if any
of my readers tries these scripts, let me know what you think of
them. I don't have any multiprocessor boxes, although I do have a
network. I just don't have time right now to experiment with these
scripts.
Syd Logan, Senior Software Engineer @ NetManage, Inc., writes:
I was perusing an old copy of The Linux Journal in preparation to do
an article or two for them on the X Image Extension when I came
across your article in the November 1996 issue. This isn't so much
about the article, but I just thought I'd drop you a line to make
you aware of my home page which is devoted to XIE at
http://www.users/cts.com/crash/s/slogan. Feel free to point any
queries you may hear about or receive regarding XIE or XIElib to
my home page, or to me directly at slogan@cts.com.
'Muse: Thanks for the note. While working for Xi Graphics I had read
the XIE specification and wondered why it hadn't been used much.
Perhaps its like X Input - it just needed a market to drive its use.
Well, the exposure Linux will give X Windows may be that driving
force. We'll have to wait and see.
Thomas Vaughan writes:
My work involves writing code in Iris GL and OpenGL. I am
particularly interested in accelerated 3D graphics, as I just
bought a ViRGE 3D accelerator for my home PC which runs linux 24
hours a day. I have played with Mesa, but there is apparently no
real free hardware support yet.
'Muse: No free support, but Xi Graphics has recently announced ViRGE
3D support in their commercial Accelerated X server.
The GGI project sounds interesting, but I don't really know whether
it's worth investigating seriously yet.
'Muse: I don't really like the idea of GGI, partly because I don't
think sticking the graphics driver in the kernel is a good idea but
also because I don't want to see the desktop interface splintered into
seperate camps. X is just really coming into its own on the desktop
and I'd like to see it continue.
At work my supervisor has, on my advice, just made a capital request
for a graphics card based on the 3D Labs Permedia chip which comes
with accelerated OpenGL support for Windows NT. In the back of my
mind, I am hoping that I can convince people at work to give linux
a serious look as a low-cost alternative to the SGI platform.
After all, even with GNU/Win32, the NT platform is not nearly as
nice as real Linux. Unfortunately, however, this seems just a
little out-of-reach at the moment, because of the apparent lack of
3D hardware support on Linux. Any news on this front would be
heartily appreciated, and I would love to write bug reports and
use either machine as a test platform.
'Muse: I got a similar request from Anand Rangarajan:
I noticed that SuSE http://www.suse.de/XSuSE/XSuSE_E.html has
developed a bunch of drivers for the ELSA Gloria family of 3D
graphics cards. Will their drivers accelerate Open GL or Mesa?
Also, these drivers are free and will be integrated into the XFree
4 release.
'Muse: Well, I thought it was about time I did a little survey of the
various graphics card vendors. See the X Server Update article below.
Marc S. Jensen writes to the GIMP User mailing list:
When I run xscanimage, it complains about my system not having a
/dev/scanner device. So, here's my question: What do I do to my
Red Hat 5.0 system to get a /dev/scanner device installed. I'm
using an Adaptec 2940 SCSI adapter, and my kernel is compiled with
SCSI support. What's wrong here?
'Muse: Assuming your scanner is the only deviced attached to your
scsi card:
ln -s /dev/sga /dev/scanner
and you're all set. If you have more than one device connected to the
scsi bus (re: cable) then you'll need to figure out which one of the
/dev/sg[x] devices maps to your scanner. Then link that one to
/dev/scanner.
Joel Becker also wrote to the GIMP User mailing list:
Just a quick question. What is a reccomened drawing tablet, for best
use and easiest XInput setup? I think I heard the Wacom ArtPad
thrown around here. Also, what is a good scanner to work with
SANE? I mean ease of setup as well as quality of image.
'Muse: Can't answer about the tablet, but I just happened to install
a scanner recently. I bought a Adaptec 2940 SCSI card and a UMAX
1200S scanner. The Adaptec dropped right in on my Pentium 200MMX
board with no hardware config necessary. The RH 4.2 distribution I
use already had the necessary scsi module prebuilt in /lib/modules
(the module name is aic7xxx.o). I ran insmod aic7xxx and up it came.
The scanner I chose from the list of scanners I reviewed last year for
my Graphics Muse column in the Linux Gazette. I first tried a 610s,
but it only worked in greyscale modes. So I exchanged it for the more
expensive (about $250) 1200s. Works quite well with the Umax
drivers. Image quality is excellent. I've been scanning hardware
(twisted pair and thinnet cables), and my hand once, and the scans
were quite good although very dark. I just brightened them up with xv
and the GIMP and all was well.
However, I haven't tried the scanner and drivers in conjunction with
SANE.
Marco Iannacone wrote:
First of all I want to say thanks for all the great stuff you wrote
(and still write) about Linux & Graphics.
'Muse: No problem.
Since a friend of mine uses Photoshop on Mac, I wanted to show how
powerfull is Linux, so I installed RedHat 5.0 on a Pentium 166
with 64Mb of RAM, with a Matrox Mystique. When I showed him GIMP
he was REALLY impressed but he found it quite slowly compared to
Photoshop. I told him that the reason was probably that XFree86
was using the generic SuperVGA driver since it doesn't have a
native driver for it.
'Muse: Possibly, but that would only make a difference in screen
updates. The majority of the GIMP's processing is done before it
updates the screen.
Is that true or maybe GIMP is only slower that Photoshop?
'Muse: Define "slower"? Slower loading the same file? Slower in
computing a new brightness or contrast? Slower how?
What he might be talking about is the use of tiles, which may appear
to update slowly, wherease in Photoshop they may all appear almost at
once (I've never used Photoshop, so I don't know if this is true or
not). So before I can answer "is GIMP slower than Photoshop" I need
to know by what means you've been measuring the two.
More than this I was not able to open any GIF, JPG or TIFF coming from
Photoshop... do you know the reason?
'Muse: You may not have installed the proper image libraries.
Download the libgr package and install it, then try again. You may
want to build the GIMP from the sources, after you install the
libraries in the libgr package. Or, if you installed GIMP from one of
the distributions (Red Hat, Debian, etc) you may want to verify you
installed all the graphics libraries that came with that distribution
too.
Tero Auvinen wrote:
In a past Graphics Muse you wrote:
...from the archive of shaders from Guido Quaroni. This archive
includes shaders from the RenderMan Companion by Steve
Upstill, from Texturing and Modeling by Ebert, Musgrave, et
al, Larry Gritz, and various other places.
Where could I get this semi-wonderous package? Found one link from
BMRT homepage, but it was defunct (anonymous ftp access denied).
If you'd happen to have it somewhere, I'd appreciate a copy,
otherways I'll just go and grab everything from the aforementioned
fellows homepages etc.
'Muse: If the link from Larry's page (the BMRT home page) is not
working I'm not certain where this package can be found. Try the
Renderman Repository: http://rmr.spinne.com/.
Also hmm, I might've missed it, highly possible, but I remember that
you 'promised' a 3 part BMRT special, seen 2 so far(issues
15&17), maybe in march issue?
'Muse: No, there wasn't a third part. I wanted to do one but I'm not
that experienced with it and I had too many other things come up.
I've never had a chance to go back and revisit it.
Re: Modellers: I can't seem to find one GOOD one, if it's nice to
look and use at, then it won't export RIB, or does it in a silly
way, using polygons and whatnot, one'd prefer RMan primitives huh?
Sure I can do the basic primitives in a non-wysiwyg way, the ascii
way. But anything more complex, no thanks.
'Muse: No modellers are available for Linux which export RIB
primitives. All of the ones I know of export polygons only.
I've been thinking on getting another computer, running only
MSWindows, networked together with linux, I could edit [3D models]
using Rhino or equivalent free Win95/NT modeler and render in
Linux. (oh yeah, now there's Win32 port of BMRT even...but Linux I
will NOT leave, Windows generally drives me nuts). Only if I had
the money.
'Muse: You couldn't pay me to run MS on anything. But thats just me.
You happen to know what Larry uses for modeling? (besides Alias on SGI
sighs..)
'Muse: I think he's got some big boxes, SGI's and Sun's probably.
I'm sure Pixar feeds him well. On Linux he may be using AC3D (as do
I). Its a pretty good modeller, but still exports everything as
polygons only. It does import 3DS and Lightwave files, though. Thats
quite useful for using the canned models from the various model sites
and CDs that are available. AC3D -
http://www.comp.lancs.ac.uk/computing/users/andy/ac3dlinux.html.
Marsel Osipov writes:
I am starting a project called Virtuoso. It's a 3D
Modeling/Animation/Rendering package for Linux. I am sure that I
would not be able to create a high quality package by myself, so
if you would like to join, visit my home page for more info.
http://www.geocities.com/SiliconValley/Lakes/7705/
'Muse: We can never have too many modellers.
______________________________________________________________________
[INLINE]
XeoMenu 1.1
One of the problems with pages based around standard HTML constructs
is the inability to easily modify navigation aides. A navigation aid
can be a set of text links, a set of images with individual links or
it can be an image map using hot spots for links. These tools allow
readers of a page to move around a Web site easily. Properly done,
they can remove the linearity (the hierarchical structure) of a Web
site and allow the reader to move freely between pages.
Adding an text links is fairly easy to do and updating them simply
requires editing the HTML. But text links lack pizazz. Images used
as text links are better, but aside from using JavaScript to do image
rollovers, the images are fairly static. They lack the feel of a real
user interface. Image maps are no better and, in fact, don't even
allow rollover changes as easily making them even more static than
individual images used as links.
Fortunately, issues such as this is part of why Java exists. Java
allows for more programmatic interfaces. These interfaces can take on
the more familiar menu-based interfaces that readers will be
accustomed to. Although it can be argued that such interfaces are not
any better than static image maps, for the sake of this article we'll
assume that menuing systems are a good thing.
XeoMenu is a simple Java program from Patrick Chan at Xeo
(www.xeo.com) that overlays a menuing system over an image in a Web
page. The program is run as an applet and is used by embedding it
within HTML source code. Readers can retrieve a copy from
http://java.sun.com:81/share/classes/menu/source/source.html. Java
source code is included, along with an example HTML file, sample
images, a users manual (a sort of man page in HTML) and the compiled
Java byte code. There is also a second version of the code, called
horizMenu, that permits menus to be layed out horizontally instead of
vertically. Since I can't seem to get Java working on my Red Hat 4.2
system (neither through the javac compiler nor through my version of
Vibe - something about my CLASSPATH is not set up right I think), I
won't be able to provide information on compiling the source in this
article. If I do get javac and/or Vibe working, I'll start talking
about how to compile Java programs. If anyone has a write up of what
I need to do to get my stock RH 4.2 version of the Java compilers
working, please drop me a line.
To use XeoMenu you need to first create an image that contains two
parts: The menu as it is displayed without the mouse over the image
and the image as it would look if the mouse were over different parts
of the original. For our example, we'll use the following image:
[INLINE] The image is divided into 2 halves. The left half is the
image as it displays without the mouse over it. The image is actually
going to be subdivided into a top (Linux) and bottom (Gazette)
section. The right side, then, shows how each section will be
displayed when the mouse is over that section. For example, if the
mouse is over the word Linux in the image then the blue Linux text
will be displayed. By default, the red colors (the left half of the
image) is displayed.
Now, in order not to annoy readers without Java support, you need to
move to the next section of this article, which will show how the Java
application is used and what it looks like when it runs. You will
need a Java compatible browser to view this part of the article.
Summary
This was just a simple example. XeoMenu itself comes with a more
sophisticated example, but there is no real explanation (ie
documentation) of what is going on in the code. Hopefully, between
that example, the user manual, and this article you'll be able to do
something useful with XeoMenu. The main applet page for Java.sun.com
shows an example of the horizontal version of XeoMenu running and its
quite slick. Although the interface uses a fairly large number of
optional parameters and the format for menu descriptions is less than
ideal, it is still a useful tool that takes only a little getting used
to in order to make a very usable menu-based interface for your Web
pages.
______________________________________________________________________
Musings
[INLINE]
X Server Update
I've been doing this column now for over a year and writing for
Linux Journal on and off for another year. In that time I haven't
really addressed one of the more obvious topics related to doing
graphics on Linux - the X server. Part of the reason for that is that
I don't have the resources to test a bunch of different server
configurations. If I got paid to do this it would be a different
story, but this column is born from whatever time and system resources
I can spare each month.
Still, I get requests fairly often asking for information about
what 3D video cards are supported under Linux and which ones support
various hardware extensions such as the X Input Extension. Most of
the questions specifically ask "which are supported under XFree86".
But some readers ask about support in general, either free or
commercial.
Well, I thought it was time I sent a query to the various vendors
and find out where things stand. The email I sent was fairly
generic. It read as follows:
Do you have any information which I may use in my column related to
your current or planned support for 3D hardware acceleration
(specifically related to OpenGL/Mesa, but not necessarily so)? What
about support for alternative input devices via the X Input
Extension. The GIMP, and its X toolkit Gtk, both make use of X
Input if available and I expect many other tools will do so as well
in the near future.
This query was sent out around the 12th of this month to Xi Graphics,
Metro Link, SuSE, and the XFree86 project. I received responses from
all 4, however Metro Link did not receive my query immediately and so
their response came in too late for this article. I will cover Metro
Link's response next month. Please note that this article is
intended to list which servers support what features/devices and is
not intended to explain how to use those features.
The responses have been edited to remove what appeared to be editorial
comments, where recognizable. I will refrain from editorializing on
these responses in this article as well.
The first reply was nearly immediate and came from Dirk H Hohndel
at SuSE. He sent two emails, one as the Vice President of The XFree86
Project, Inc. and one as the Lead Developer, S.u.S.E. GmbH. Dirk
wears both hats, and therefore his comments are considered official
responses, one from each organization. Both responses were direct and
to the point. First his XFree86 response:
Well, XSuSE and XFree86 are mostly identical. As far as legally
possible, all work done on XSuSE is integrated into the next XFree86
version. XFree86 in itself focuses on the X Window System and 2D
support for the different cards. While they are not actively pursuing
3D support, they are in contact with several groups working in that
area.
I do not speak for Metro Link, but I can tell you that Metro Link and
XFree86 are in very positive cooperation on the 2D side of servers.
Metro Link donated lots of code to XFree86 recently, and Metro Link
and XFree86 are working together on many aspects of the design of our
future X servers.
Because Dirk's response came quickly, and because responses from the
other vendors provided more detailed information, I thought I should
offere XFree86 a chance to expand their reply. When asked to comment
on architectural details and XFree86's relationship to the commercial
vendors, Dirk responded:
Why would I bore you or anyone else with architectural details that no
one really cares about.
He followed up his XFree86 reply with a response from SuSE:
SuSE is working on hardware 3D support, but there is no release date
for that, yet.
The 2D drivers from SuSE are intended to be integrated into
XFree86-4.0, but we are currently running into some legal problems
with that for one of them (3DLabs GLINT), as some of the docs are
under NDA and we have not been able to get the permission to release
sources, yet. We are working on it, though. All the other drivers
from SuSE have already been included into XFree86-3.3.2
The other replies came from Xi Graphics. Both Thomas Roell, President
of Xi Graphics and technical architect for their servers, and Jeremy
Chatfield responded.
Thomas wrote:
Our next generation X-Server will support additional new input devices
for the XInputExtension. The extension itself is supported since
Accelerated-X 4.1. Planned devices are mainly CAD oriented input
systems, like Tablets, Touchscreens and Space-Balls. As for Hardware
3D, you can bet that the next generation will have that.
Jeremy Chatfield followed up with the following (edited partially for
length):
Accelerated-X 4.1 supports the XInputExtension, using a small and
fixed list of devices, with very limited device management. Future
releases will support a wider range of devices.
We've been evolving Accelerated-X ever since 1994, to take advantage
of 3D hardware acceleration. Examples of the technology introductions
and the reason for needing them for 3D support:
* Memory allocation and buffer management. 3D uses a lot of
memory. Standard malloc() (as of 1994, when we started this work)
did not permit programs to decrease in size, tended to thrash
memory when freeing and sometimes when allocating, and exhibited
other behaviors that were not suitable to long running processes
with a mix of temporary and long term storage in a wide variety of
data sizes. We do things like lazy buffer allocation, only
allocating stencil buffers when needed, and so on. This improves
speed and reduces system impact, seen in total Server size, and
paging demand.
-Top of next column-
[INLINE]
More Musings...
VRWave 0.9
--
[INLINE]
* Coprocessor locking. When using the host processor, graphics
engine and 3D engine, all writing in the same memory areas, and
when using both system memory (via AGP) and graphics board memory,
fast and correct mutex locking is essential. [Without locking]
this will cause problems when all three processors (or more)
attempt to handle the same memory. We have continued to refine
our mutex locking for several years, though this is not visible in
any product other than multihead, at present.
* Asynchronous I/O When X Servers with high levels of hardware
acceleration are handling buffered drawing requests, keyboard and
mouse input is put into the end of the queue. This results in
sluggish response, and in mouse and keyboard data being handled in
bursts. Mouse acceleration can be triggered inappropriately, so
mouse motion becomes very hard to control, and sequential single
button clicks can be misinterpreted as double clicks. We
introduced the "Velvet Mouse" mechanism to permit input even while
the Server was in heavy rendering, as will be typical of 3D
dynamic applications.
* Overlays. Many 3D applications on workstations rely on the
presence of overlays. [Overlays] also benefit from the memory
management and other architectural changes in Accelerated-X.
Xi Graphics recently announce support for ViRGE 3D (see the February
1998 Graphics Muse).
Beyond these two vendors, there is also 3D hardware support available
for Mesa for the following video hardware:
* 3Dfx Voodoo - Cards based on the 3Dfx Voodoo chipset (such as
Diamond Monster 3D and Orchid - Righteous 3D) are supported under
Linux and Windows 95. Look here for the latest info. This is the
best supported 3-D hardware for Linux at this time.
* 3Dfx Voodoo Rush (rendering into window) - Supported under
Windows. Linux support is underway.
* GLINT-based boards - Look here for the latest info.
* Cirrus Mondello - No longer supported- download Mesa 1.2.8 if
you're interested in this driver.
This information was taken directly from the Mesa Web pages. I
ignored any cards for which Linux was not mentioned except the Cirrus
Mondello. I don't know if its for Linux or Windows. Also, I don't
know exactly how Mesa makes use of this hardware without actually
being part of the X server. You will have to investigate the Mesa
pages and its links for more information in that area.
So, now you should know as much as I do with respect to 3D and X Input
support from XFree86/SuSE and Xi Graphics. In summary, most of the 3D
work seems to be planned and under development, but no word on when
the support (at least for wide spread 3D support) will be available.
Neither XFree86/SuSE nor Xi specifically mentioned any 3D boards being
supported, although Xi did have the announcement for the ViRGE 3D last
month. Xi stated they support the X Input Extension in their
Accelerated-X 4.1 release. Although XFree86 didn't mention it, I know
that X Input is supported in their product as well. Don't forget:
I'll be covering Metro Link's responses to my query next month.
I should mention again that I have worked for Xi Graphics in the past,
and in fact worked with both Thomas and Jeremy at Dell computer and
with Jeremy at Information Foundation (a USL source code licensee back
around 1993 or so). I have made every attempt to remove all editorial
comments, both my own and any from the respondents, from this article.
Contact Information
XFree86:
* Announcements: comp.os.linux.announce and other announcement
groups
* Web site: http://www.xfree86.org
* Support: XFree86@XFree86.Org
* Business: BOD@XFree86.Org
S.u.S.E.:
* Announcements: comp.os.linux.announce
* Web site: http://www.suse.de/XSuSE/XSuSE_E.html
* Support: x@suse.de
* Business: x@suse.de
Dirk reports: In both cases we try to keep the web pages up to date
and XFree86 has a FAQ online that contains workarounds for known bugs.
Xi Graphics:
* Announcements: accelx-announce-request@xig.com with the one word
message "subscribe"
* Web: http://www.xig.com
* User-to-User mailing list: accelx-users-request@xig.com with the
one word message "subscribe"
* Email: sales@xig.com - automated initial response, but a human
reader.
* Phone: +1 800 946-7433 (US), +1 303 298-7478 (Int'l).
* Fax: +1 303 298-1406
Jeremy added: We keep the web site up to date.
[INLINE]
Resources The following links are just starting points for finding
more information about computer graphics and multimedia in general for
Linux systems. If you have some application specific information for
me, I'll add them to my other pages or you can contact the maintainer
of some other web site. I'll consider adding other general references
here, but application or site specific information needs to go into
one of the following general references and not listed here.
Linux Graphics mini-Howto
Unix Graphics Utilities
Linux Multimedia Page
Some of the Mailing Lists and Newsgroups I keep an eye on and where I
get much of the information in this column:
The Gimp User and Gimp Developer Mailing Lists.
The IRTC-L discussion list
comp.graphics.rendering.raytracing
comp.graphics.rendering.renderman
comp.graphics.api.opengl
comp.os.linux.announce [INLINE]
Future Directions
Next month: Unknown. I've got some prior obligations (paying ones,
that is) that I absolutely must get done. And soon.
Let me know what you'd like to hear about!
______________________________________________________________________
© 1998 Michael J. Hammel
_________________________________________________________________
Copyright © 1998, Michael J. Hammel
Published in Issue 26 of Linux Gazette, March 1998
_________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
_________________________________________________________________
More...
Musings
indent
© 1998 Michael J. Hammel
indent
VRWave 0.9
Quite some time ago a reader, a fellow named Paulo, had sent me email
asking if I had taken a look at VRWave yet. This is a VRML 2.0
browser available from the Institute for Information Processing and
Computer Supported New Media (IICM), GrazUniversity of Technology,
Austria. The program is freely available for private use and includes
source code. The current version, 0.9, includes a Java-based port of
the code, although all rendering code is still in C using either
OpenGL or Mesa.
Looking through my backlog of things to do for the Muse, I decided to
take a look at VRWave. At a minimum I wanted to see if I could simply
get it to run. Hopefully, I would be able to say something
intelligent about the source code and build environment as well. I
jumped on the Internet and went off to grab a copy of the package from
a US mirror of the VRWave Home Page (http://www.iicm.edu/vrwave). The
first thing I noticed was that there were both source and binary
distributions available. The binary distributions cover a few flavors
of Unix, including ports for Linux 2.0. There are actually two
versions of the binary distribution - a Java 1.1.3 based version and a
Mesa version which uses Java 1.0.2. These are actually the platform
specific libraries needed by VRWave. I grabbed both along with the
gzipped Common tar file which must accompany any binary version that
is downloaded. The Mesa version is not compiled with any of the
hardware accelerated drivers available for Mesa. If you want to use
those drivers you need to recompile the source with the Mesa package
properly built with the drivers of interest. Also, the Mesa code is
statically linked into the platform specific libraries, so you
shouldn't need any other libraries or files outside of those contained
in the Common tar file and the platform specific tar file.
The directions say to unpack the Common file first, then cd into the
vrwave-0.9 directory this process creates and unpack the platform
specific files. The first time I did this I didn't do it in the right
order and got myself confused. So I redid the unpacking, following
the directions. Its true - men never read the directions. The
instructructions in the INSTALLATION file for running VRWave are quite
complete so I won't rehash them here. Just be sure you actually read
the file! In my environment I use Java 1.0.2, the default
installation of Java on Red Hat 4.2, so I set my CPU environment
variable to LINUX_ELF. You may need to set it to LINUX_J113 if you
have the Java 1.1.3 package installed on your system.
Once you set up a couple of environment variables you're ready to
start vrwave. Since VRWave uses your Java runtime environment, be
sure your CLASSPATH is set correctly first. On my Red Hat 4.2 system
I have it set as follows:
CLASSPATH=/usr/lib/java/lib:/usr/lib/java/lib/classes:/home/mjhammel/s
rc/graphics/vrwave-0.9/classes
Type vrwave and the interface opens a window. On my system I got
messages like the following:
java.lang.InternalError: unsupported screen depth
VRwave: could not load icons at
/home/mjhammel/src/graphics/vrwave2/vrwave-0.9/icons.gif
VRwave: could not load logo at
/home/mjhammel/src/graphics/vrwave2/vrwave-0.9/logo.gif
java.lang.InternalError: unsupported screen depth
at
sun.awt.image.ImageRepresentation.setPixels(ImageRepresentation.java:1
70)
at
sun.awt.image.InputStreamImageSource.setPixels(InputStreamImageSource.
java:459)
at
sun.awt.image.GifImageDecoder.sendPixels(GifImageDecoder.java:243)
at
sun.awt.image.GifImageDecoder.readImage(GifImageDecoder.java:295)
at
sun.awt.image.GifImageDecoder.produceImage(GifImageDecoder.java:155)
at
sun.awt.image.InputStreamImageSource.doFetch(InputStreamImageSource.ja
va:215)
at sun.awt.image.ImageFetcher.run(ImageFetcher.java:98)
at
sun.awt.image.ImageRepresentation.setPixels(ImageRepresentation.java:1
70)
at
sun.awt.image.InputStreamImageSource.setPixels(InputStreamImageSource.
java:459)
at
sun.awt.image.GifImageDecoder.sendPixels(GifImageDecoder.java:243)
at
sun.awt.image.GifImageDecoder.readImage(GifImageDecoder.java:295)
at
sun.awt.image.GifImageDecoder.produceImage(GifImageDecoder.java:155)
at
sun.awt.image.InputStreamImageSource.doFetch(InputStreamImageSource.ja
va:215)
at sun.awt.image.ImageFetcher.run(ImageFetcher.java:98)
These may be due to either an incorrect Java configuration on my
system or because the Java 1.0.2 libraries do not support the
TrueColor (24 bit depth) visual I'm running with my X server. In
either case it didn't seem to matter, as the window opened and I was
able to begin playing with VRWave. Also, during all my
experimentation I had no display or color problems at all.
The first thing I should say at this point is that I know very little
about VRML other than its a language for describing navigable 3D
worlds. VRML 2.0 includes features such as spatial sound, where the
sound of an object in the distance can grow louder as the object is
moved closer. To my knowledge VRWave does not yet support sounds, but
I didn't test any VRML worlds in which sound was availalble. In any
case, what I'll describe here is what an casual user might encounter,
what someone who is just beginning to explore VRML might find
interesting and useful. Also please note that the slight blur in the
images is due to reducing them from the screen captures in order to
fit the image in a 640 pixel wide Web browser.
The interface
[INLINE]
The image above show the initial window if no input file is provided
on the command line. You can specify any VRML file as an input file.
These carry the .wrl extension in the file name and you can find
numerous example in the examples directory in the distribution.
Scene files are ordinary text files, not unlike the POV-Ray
programming language in a sense. The look like the sample code below,
which is the code for the convexify.wrl example:
#VRML V2.0 utf8
# sample for applying perface materials onto non-convex shape
# kwagen/mpichler
Viewpoint
{
position 5 5.25 10
orientation -0.6 0.8 0.1 0.5
}
Shape
{
geometry IndexedFaceSet
{
coord Coordinate
{
point [ 0 0 1, 1 0 1, 3 4 1, 2 4 1, 1 2 1, 1 4 1, 0 4 1,
0 0 0, 1 0 0, 3 4 0, 2 4 0, 1 2 0, 1 4 0, 0 4 0 ]
}
coordIndex
[
0 1 2 3 4 5 6 -1 # front, lt. green
0 7 8 1 -1 # red
1 8 9 2 -1 # blue
2 9 10 3 -1 # yellow
3 10 11 4 -1 # cyan
4 11 12 5 -1 # magenta
5 12 13 6 -1 # dk. cyan
6 13 7 0 -1 # dk. magenta
13 12 11 10 9 8 7 # back, dk. green
]
color Color { color [ 0 1 0, 1 0 0, 0 0 1, 1 1 0, 0 1 1, 1 0
1, 0 0.5 0.5, 0.5 0 0.5, 0 0.5 0 ] }
# colorIndex [ 8 7 6 5 4 3 2 1 0 ] # reverse color binding
colorPerVertex FALSE
convex FALSE
}
}
The following table summarizes most of the features in the VRWave main
window:
Window Feature Description
File Basic file input/output functions, plus camera information.
Navigate Set mode for movement through VRML world; reset and align
functions for current view.
Display Lighting, rendering (static and interative) methods, colors,
background, transparency, etc.
Help HTML based help system that relies on Netscape. Netscape must
be in your path for this to function properly.
Flip Navigation mode; Scene translation around origin and zoom.
Walk Navigation mode; move forward, backwards, sideways pan and move
"eyes".
Fly To Navigation mode; sets a Point of Interest from which all other
movements in this mode are relative.
Heads Up Places a "heads up display" in the center of the viewing
area; 3 navigation types in display: eyes, body and pan. These
correspond to the same types of movements that Walk provides but gives
visual cues to movement settings.
Behaviour Purpose unknown
Interaction Purpose unknown
Navigation
In the following example, the sample scene examples/office2.wrl was
opened (File->Open) into the default window (ie the window was not
resized or adjusted in any way). To move around this scene you can
use the mouse or keyboard. Keyboard bindings are described in the
help/mouse.html file, which will also give you a little more
information about what kind of movements within a scene are available.
An example of movement through this scene would be to hold down the
middle mouse button (with the Flip button pressed as it is in the
example image below) and drag it around the viewing area. This would
rotate the entire room and its contents around the origin, which is
positioned, but not visible, in the middle of the viewing area. When
this movement is started the image will change to a wireframe view to
speed processing. The use of wireframe, flat shaded, smooth shaded
and textured objects during navigation and static display (when you
aren't moving the scene around) can be controlled from the Display
option in the menu bar.
[INLINE]
examples/office2.wrl example scene
[INLINE]
examples/office2.wrl example scene in wireframe mode
This scene is probably the nicest image, asthetically speaking, of all
the examples. The image fills the viewable area and is a complete
room. If you navigate around the room you quickly learn that the
walls to the room disappear if you're viewing area would be blocked by
those walls For example, tilt the room down, then rotate it to the
left. You're view of the room is now outside of the right wall, but
in order to view the inside of the room the right wall is not drawn.
You can change this behaviour by using the Display->Two-sided Polygons
option and setting this option "On". The default setting, Auto, will
not display the wall if it gets in your way. Turning this option on
causes the back sides of the walls to become visible, and so your view
inside the room is blocked.
[INLINE]
examples/sensors/touchsensor.wrl, with the Display->Background
set to gray and the Heads Up Navigation button set.
In this next example the Heads Up option is selected and you can see
the three view functions displayed in the middle of the viewing area.
These small boxes don't move with the rest of the scene as you drag it
around the viewing window. They stay centered in that window. A red
line is drawn from the center of one of these boxes to the current
cursor location showing direction and speed (longer lines give faster
speed).
The movement of the small sphere in this image is managed through the
use of the left mouse button, but only when the cursor is over the
large green box. Moving the cursor, left mouse button held down,
moves the sphere around the viewing area. If the mouse leaves the
area of the box then the sphere stops moving. Note that the area of
the box does not mean just a side of the box - it means what ever
region of the box is actually visible to the user.
If you have a fast enough computer and enough memory you can turn on
interactive texturing. This allows you to view the the objects in the
scene with their full textures displayed while you move the scenes and
objects around the viewing area. Although I can't show this feature
here, I can show you another example scene which has a texture map
applied to the sides of a cube. The first example shows the texturing
on a cube with Two-sided Polygons turned off. The next example, which
is a full sized capture so you can see the details a little better,
shows the same image with Two-sided Polygons turned on.
[INLINE]
examples/isub/cube.wrl, with static texturing turned on
[INLINE]
Same image, but with two sided polygons turned on so
you can see the transparent parts of the image better.
Visiting VRML 2.0 URLs
VRWave's beta Netscape plug-in does not work with Netscape 4.0 due to
changes from 3.0 to 4.0 in Netscapes security code. Since I use the
4.03 release at home I was not able to test the plug-in. Also, since
all of the VRML sites I visited used VRML embedded in HTML, and since
those pages caused my 4.03 version of Netscape to crash when I tried
to load them, I wasn't able to test the mime/type installation that
would launch VRWave as an external viewer. I also tried to download a
newer version of Netscape, but my connection kept timing out during
the download (its about 10Mb now). This is what I get for waiting
till the last few days before my deadline for this column before
trying to get this all working. Its my fault - not VRWaves.
Getting Help and other information
There is a Help option in the menu bar at the top of the interface.
This requires that Netscape be in your path so that VRWave can launch
it. If Netscape is already running, it won't matter, since VRWave
still needs to try to run Netscape first, so it still must be in your
PATH before running VRWave. I'm not sure if I prefer this or would
rather see them use the NetHelp inteface for Netscape. I think I
prefer the latter, although NetHelp may not be accessible from Java
(I use an Xlib based API for it).
The README file that comes with the binary distribution states that an
online users guide for VRWeb (VRWave's predecessor) is available from
http://www.iicm.edu/vrweb/help. However, this link doesn't seem to
work any more. I browsed the main VRWave web site and found a link to
http://www.iicm.edu/vrwave/release, which contains various online
documentation. Unfortunately, I didn't find a users guide per se.
The best printed help available will be the help/install.html and
help/mouse.html files in the runtime directories from the binary
distribution. In particular, the mouse.html file contains detailed
information about mouse and keyboard bindings for scene navigation.
Compiling from source
The bad news here is that my Java development environment just doesn't
seem to be working and so I can't talk intelligently about building
VRWave from the source distribution. I had my Java environment
marginally working in Denver, but when I moved to Dallas I must have
changed something because neither javac nor Vibe seem to be working
any more. It may be time to upgrade to Red Hat 5.0 anyway, so maybe
I'll fix it then.
To Wave or not to Wave
The question remains: is VRWave a good tool for viewing and learning
about VRML? Yes, absolutely. Its still early in its development but
the tool is very stable, it didn't crash at all on any test files I
loaded (although I was only able to use the example files in the
distribution). Some things I'd like to see is a little better help
system or at least one that can allow me to configure where Netscape
is (since I used to upgrade often I didn't have it in my path, I have
a script that knows how to find it). The URL feature is handy but it
would be nice to be able to select from a list of URLs. Such a
feature is more the realm of a browser than a VRML viewer. I suppose
it depends on which VRWave wants to be in the long run.
If you are just getting started with VRML and would just like to look
at a few examples, this is a good place to start. You will need to
have a working Java environment - one that can run Java applets if not
compile Java code. Other than that, installation is a breeze and
there are enough example files to keep you at least midly entertained
until you can write your own VRML worlds.
indent
© 1998 by Michael J. Hammel
More...
Musings
indent
© 1998 Michael J. Hammel
indent
...XeoMenu (continued)
This first example shows the basic workings of XeoMenu. Note that
when you place the mouse over either word in the image it changes
colors and shifts slightly in position. The latter was originally
just a typo but I liked it the effect so much I left it in. The
"Linux" text also provides a drop down menu when you place your cursor
over it. The menu contains two simple entries. Moving the mouse over
either entry would take you to another page (although the links in
this source are fictitious - they don't really exist).
The applet code for this first example looks like this:
<APPLET CODEBASE="." CODE="XeoMenu" WIDTH=150 HEIGHT=200>
<PARAM NAME=copyright VALUE="(c) 1997 Sun Microsystems Inc. All
Rights Reserved.">
<PARAM NAME=author value="Patrick Chan. www.xeo.com">
<PARAM NAME=bg-color value="206 114 28">
<PARAM NAME=image VALUE="./gx/hammel/xeomenu-1.gif">
<PARAM NAME=separator VALUE="|">
<PARAM NAMe=newline VALUE="^">
<PARAM NAME=font VALUE="Helvetica">
<PARAM NAME=font-height VALUE="18">
<PARAM NAME=marginh VALUE=2>
<PARAM NAME=marginv VALUE=2>
<param name=fg-menu-color value="0 0 0">
<param name=bg-menu-color value="206 114 28">
<param name=fg-hi-menu-color value="232 221 18">
<param name=bg-hi-menu-color value="206 114 28">
<!-- param name=target value="_self" -->
<PARAM NAME=menu0
VALUE="0 0 150 100|151 0 150 100|0 0|d|/path/to/file-1.html|What
is Linux?|/path/to/file-2.html|How can I get
it?|/path/to/file-3.html">
<PARAM NAME=menu1
VALUE="0 101 150 100|151 101 150 100|0
101|d|/nav/new/index.html">
</APPLET>
We'll step through these one time to explain briefly what each line
does. The first line starts the applet code and establishes the
current directory (the one from which this page was taken) as the
location for the applet code. The CODE argument gives the name of the
Java program. Note that you don't have to include the ".class"
extension (all Java programs, once compiled, have a .class extension
in the filename). The width and height arguments give the dimensions
in which the applet will live in the page. Note that this code was
placed right after a table, inside the BODY section of the HTML
document. After this line come the set of applet parameters, each of
which is specified using the HTML PARAM tag.
The next two lines give the copyright and program author, giving
credit to Sun Microsystems and Patrick Chan for this code. Sun paid
Xeo for its development, I believe, for use on the Java Web site.
The next line gives a background color to use in the transparent
regions of the image. This particular example does not have any
transparent areas, however the next one does.
The image to use is specified with the image parameter line. The
VALUE can be any valid URL.
The seperator is a single character used to delimit fields in the menu
parameters. The menu parameters are the last two PARAM entries which
we'll cover in a moment. For now, just note that the seperator is
used in the VALUE argument for the menu parameters.
Menu items can have multiple lines using this program. In order for
XeoMenu to recognize a line break, the text uses a caret (^) to denote
a newline. These are not used in these examples, but the caret would
be embedded in the menu text in the menu parameters.
The next two lines specify the font and font height to use for the
menu text. According to the man page for XeoMenu there are only 3
possible font types: Helvetica, TimesRoman, and Courier. This is
probably a limitation in the early Java class libraries, but I'm not
certain of that.
Marginh and marginv are used to pad the region around the menu text
with empty space. The values are given in pixels.
Now come the text color parameters. First are the foreground and
background colors to use for the text when the cursor has not been
moved over the text, ie the default text colors. The latter two
specify the colors to use when the cursor is placed over a menu
entry. Note that in the first example the background colors are the
same but the foreground colors are changed. This isn't a recommended
method - the results are somewhat unappealing - but it does give you
an idea of how the colors can provide variations of effects.
The last line before the two menu parameteers is actually commented
out, but is given for the sake of completeness. This parameter is
recognized by XeoMenu as the frame to display a menu items targe URL
if it is selected.
Finally, we have the two menu parameters. XeoMenu recognizes any
parameter prefixed with the word "menu" and suffixed with a numeric
value as a menu item. This parameters value field contains a set of
seperator delimited values that define the display location, contents,
and URLs for each menu. The first set of 4 numbers is the hotspot.
This is the region, specified by an x,y location and its width and
height, in which the mouse must enter for XeoMenu to begin handling
the menu features of the image. The next 4 numbers specify a
secondary region of the image to overlay on the image when the mouse
enters the hotspot. The next two numbers specify the offset into the
image to place the overlay. In this example the offsets are specified
so the overlay is place over the hotspot, blotting it out as it were.
This is not the only way to use this feature, since the overlay can be
placed anywhere on the image. Note that all of the x,y coordinates
are given as pixel coordinates in the image.
After the offset comes a single character. This can either be a "d"
or a "u". The "d" is used to post menus in a downward direction and
the "u" draws them upward. The location of the upper left corner for
the downward menus (and the lower left corner for upperward menus) is
also the offsets specified for the overlay location (ie the two
numbers that preceeded the "d" or "u").
Next comes the default URL. This is the URL that will be used if the
user simply clicks in the hotspot without actually using a menu.
After this comes the menu definitions. These are the text of the menu
entries paired with a URL that follows immediately after it. Note
that in the second menu parameter there is only one URL specified -
the default URL. That means that no drop down menus are displayed
when you place the mouse over the Gazette hotspot, but the overlay is
still used.
In this next example, both regions of text use menus. One uses an
upward menu and the other uses an overlay that is not directly over
the original hotspot. Also, this image has a transparent region. Can
you guess how to create this example? Try it first, before looking at
the source code.
Back to the main Muse page.
indent
© 1998 by Michael J. Hammel
"Linux Gazette...making Linux just a little more fun!"
_________________________________________________________________
next up previous
Next: Characteristics and chipset
Linux on a Kapok 7200
4.2.98 version 1.0
Alessandro Usseglio Viretta
Lab for EM 1
Schmelzbergstrasse 7, CH-8092 Zurich
e-mail: usseglio@biol.ethz.ch
Fax + 41 1 6321103
Abstract:
The Kapok 7200 is a portable computer, Intel-based, manufactured by
Kapok - http://www.kapok.com.tw - in Taiwan. It is sold under a
variety of names is USA and Europe. BSI http://www.bsicomputer.com,
ATC http://www.at-computers.com, NewChip http://www.newchip.it, AJP
http://www.ajp.co.uk, JET http://www.jet.ch, A&O
http://www.aocomputer.com, Computer Direct http://www.direct.ch,
Gericom http://www.gericom.com, Pro Star http://www.pro-star.com,
Megashop http://www.megashop.ch are just a few vendors of this
computer. It's a bulky and heavy computer, but it's provided with a
big nice TFT screen - up to 14.1" - and a easily upgradable Pentium
MMX processor. It is usually delivered with Windows 95 already
installed. The aim of this document is to explain how to install Linux
on such a machine. If you want to keep Windows, please refer to the
HOWTOs available, for example, at
http://sunsite.unc.edu/pub/Linux/docs/. This document is aimed to
absolute beginners and is not intended to provide a deep insight into
the Linux operating system. After reading it, the newby should be
ready to successfully install a RedHat Linux system on his/her laptop
and start working with it.
_________________________________________________________________
* Characteristics and chipset
* Installing Linux
+ Where to get RedHat Linux
+ Partitions
+ Which packages?
* X Window
+ XF86Config
+ Which window manager?
* XDM
* PCMCIA
* Networking
+ Ethernet
+ PPP
* Kernel
* Copyright notice and disclaimer
* About this document ...
_________________________________________________________________
Copyright © 1998, Alessandro Usseglio Viretta
Published in Issue 26 of Linux Gazette, March 1998
_________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
_________________________________________________________________
"Linux Gazette...making Linux just a little more fun!"
_________________________________________________________________
Low Cost Macintosh-Linux Networking at Home
by Dr. Richard L. Dubs
_________________________________________________________________
Contents:
* I. Introduction
* II. Network Overview
* III. Network Hardware and Software
* IV. Setting Up
* V. Operations
* VI. Final Comments
I. Introduction
Only one hour after I taught my wife, Lois, how to access the Internet
with our Macintosh Quadra 605, I knew that my dream of having a
Linux-based home network would be realized. Surely, I reasoned, it
would now be unacceptable for me to "hog" our Internet connection and
prevent Lois from tracking down Star Trek Collector's Cards online.
Fortunately I had used Linux IP Masquerading in a previous life as a
LAN administrator and knew that a Linux solution would allow us both
to be on the Internet at the same time with only a single modem
connection and IP address from our Internet Service Provider.
There were a couple of constraints, however. First, there was no space
in my family room for another computer; any additional system would
have to be set up in the basement. Second, our Mac did not have an
Ethernet card, nor was I inclined to pull Ethernet cable through my
house. Third, any solution would have to be achieved on a shoestring
budget (Did you hear the one about the guy whose wife had her credit
cards stolen, and the guy didn't report it because the thief spent
less than the wife?)
This article describes the Linux networking solution I came up with -
it consists of my Mac, a Linux Box and a low cost dos-based router. It
is not "state of the art", but it is a solution that works within the
constraints I imposed, it is relatively simple, and it is one that
many people haven't heard about before. As you will see, it heavily
leverages software and information available on the Internet. Mac,
DOS, and Linux users will all find something of interest in the
material presented herein.
The remainder of this article is organized as follows: Section II
presents an overview of my home network; Section III describes the
network hardware and software; Section IV addresses setting up;
Section V describes operations; and Section VI presents final
comments, including things to try.
II. Network Overview
[INLINE]
Figure 1 presents a schematic of my home network. My Macintosh (family
room) has connectivity to my Linux box (basement) through a low cost
dos-based router (also basement). The Macintosh-router segment is
LocalTalk and the router-Linux box segment is Ethernet (thinnet). The
Linux box provides the dialup PPP connection to my Internet Service
Provider (ISP) and runs IP Masquerading which allows the Macintosh and
the Linux box to use the Internet at the same time through the single
dialup connection.
III. Network Hardware and Software
LocalTalk
LocalTalk seemed the best way to establish connectivity between my
family room (Mac) and my basement (PC's) for two reasons:
* LocalTalk support is already built into every Macintosh. I didn't
have to buy additional hardware for my Mac.
* A LocalTalk network can be run over ordinary phone lines. I used
the free pair of wires in the existing telephone line in my house
for the localtalk segment of my LAN.
Some people might say that LocalTalk, at 230 KB/sec is too slow to be
useful for networking. (Ethernet, in comparison, is 10MB/sec).
However, my modem connection is only 14.4 KB/sec (57.6 KB/sec maximum
throughput) making LocalTalk seem more than adequate.
Router
Having a LocalTalk connection from my Mac to my basement still didn't
help me connect to my Linux box. Linux does offer AppleTalk support,
but it does not yet offer support for LocalTalk (although I understand
the hooks for LocalTalk are now built into the AppleTalk code).
Figure 1. Schematic of My Mac-Linux Home Network
That's where the free router software, PCROUTE by Vance Morrison,
comes in. PCROUTE is dos-based software available on the Internet
(PCRTE224.ZIP at http://www.nova.edu/Inter-Links/simtel/network.html)
that routes TCP/IP packets between LocalTalk and Ethernet networks.
PCROUTE can run on a PC XT or better ( and it doesn't require an
AppleTalk - IP Gateway like the LocalTalk packet driver-based routers
such as KA9Q). Once PCROUTE is set up correctly, you don't even need a
keyboard or monitor if your computer can boot without them. I run
PCROUTE on an old 386 PC with 1Meg of Ram and a 5.25 inch floppy
drive.
PCROUTE comes with excellent instructions on how to compile and
configure it as a LocalTalk/Ethernet router. Of course the router
needs both a LocalTalk PC card and an Ethernet card. The latter I
already had and the former I bought for $27 + shipping from
MacResource Computers, a Texas-based company I found on the Internet
(http://www.mac-resource.com/mac-resource/).
Some more comments about the LocalTalk connection between my Mac and
the router. To use phone lines for LocalTalk, both my Mac and the
router required LocalTalk/RJ-11 adapters. The 8 pin mini-din variety
is available at any computer superstore, however, the LocalTalk PC
board required the older 9 pin variety. Those are easy enough to find
for sale on the Internet, but I found the circuit itself on the
Internet instead
(http://www.jura2.uni-hamburg.de/~kai/LAM_HTME/cap1.htm)! It turns out
that you can build the 8 or 9 pin variety with only 5 resistors, 2
capacitors, and some miscellaneous parts - and it all fits in a 35mm
film canister! I built one for my router and it works great. (One word
of caution - the pinouts for the 9 pin adapter or left/right backward
in the figure provided with the circuit.)
I have a single phone line in my house; it uses the inner red and
green wires of the modular phone plug for the telephone connection.
The outer black and yellow wires are available for LocalTalk.
Fortunately, LocalTalk/RJ-11 adapters are already wired to use the
outer wires.
Linux
My Linux box is a 486DX33 PC with 16Megs of Ram, a 270MB hard disk,
and a 14.4 baud Modem. It uses a thinnet Ethernet connection to the
router. The only unusual part of installing Linux was that my 486 does
not have a CD-ROM drive. To load the Linux software, I decided I
needed to get the software on the DOS partition of my 486 so I could
install Linux from there.
To accomplish this I temporarily installed the LocalTalk PC card in
the 486 and loaded the software that came with the card. The software
allows you to mount Macintosh folders as letter drives (e.g. f:) on
your PC. I simply copied the Linux installation software off the
CD-ROM into a folder on my Macintosh hard disk, mounted that folder
over the LocalTalk network as drive f: on the 486, and used XCOPY to
move all the LINUX software to my 486 (e.g. XCOPY f:*.* c: /s /e).
IV. Setting Up
I followed RFC 1597, which allocates certain IP addresses for private
networks, and internally assigned 192.168.1.x for my LocalTalk segment
and 192.168.2.x for my Ethernet segment. In the next three sections, I
provide specific instructions for configuring the network.
Macintosh Setup
The Macintosh setup is straightforward. Select MacTCP from the control
panel. In the first MACTCP window, select the "More" button. In the
second window, set the server to "Manual" and the gateway IP to
192.168.1.1 (This is the IP address for the router's LocalTalk PC
card). I leave the DNS servers the same as I use to access the
Internet directly with my Mac's modem.
Click "OK" to return to the first MacTCP screen. On the first screen,
change the Mac's IP address to 192.168.1.2 and select the LocalTalk
icon. Make sure that LocalTalk is turned on in the Chooser.
Router Setup
PCROUTE comes with excellent documentation which I will not repeat
here. I set up the LocalTalk interface with an IP address of
192.168.1.1 and the Ethernet interface with an IP address of
192.168.2.1. For the Ethernet interface I have successfully compiled
and run two different configurations of PCROUTE, one that uses a
direct interface to an 8 bit WD8003 Ethernet card and one that uses an
Ethernet packet driver interface. The nice feature of the packet
driver interface is that it allows you to use any Ethernet card for
which a packet driver exists. I have successfully used PCROUTE with
both the WD8003 card and a 16-bit NE2000 compatible card using packet
drivers.
In the router, I set a static default route to 192.168.2.2 (the Linux
box) so that any IP address not recognized by the router (e.g. www
sites from my Mac intended for the Internet) will be routed by default
to the Linux box.
A neat feature of PCROUTE is that it allows you to designate the Linux
box as a syslogd host that logs status messages from the router. When
the router starts up, and approximately every 15 minutes thereafter,
the router sends the Linux box a "Router is up" message that is
recorded in a file on the Linux box that you specify.
Linux Setup
I set the IP address for the Linux Ethernet interface to 192.168.2.2
and designated the router (192.168.2.1) as the gateway for packets
addressed to the LocalTalk segment (192.168.1.x).
To log syslog messages from the router, edit the /etc/syslog.conf file
as described in the PCROUTE documentation. Then reboot Linux or type
kill -HUP <pid>, where pid is the syslogd process id obtained by
typing ps -x.
IP Masquerading
As stated earlier, I use IP Masquerading to give my Mac and Linux box
simultaneous access to the Internet through a single PPP connection to
my ISP. However, because I use Linux 1.2.13, the IP Masquerading
capability has to be built into the kernel as a patch. Fortunately, IP
Masquerading comes with excellent instructions for applying the patch.
To configure IP masquerading, I use:
ipfw a m all from 192.168.2.0/24 to 0.0.0.0/0
ipfw a m all from 192.168.1.0/24 to 0.0.0.0/0
These steps will automatically masquerade my Mac and any future
computer I add to either my LocalTalk segment or my Ethernet segment.
If you don't want to retype these lines each time you reboot your
computer, add the steps to one of the startup scripts executed from
the /etc/rc.d directory.
I will not describe setting up a PPP connection from my Linux box to
my ISP; good instructions are already provided in the Linux How-To
documents. When the PPP link is up and running and IP Masquerading is
set up as described, my routing table (obtained by typing "route -n")
looks like:
Destination Gateway Genmask Iface
207.96.96.102 * 255.255.255.255 ppp0
192.168.2.0 * 255.255.255.0 eth0
192.168.1.0 192.168.2.1 255.255.255.0 eth0
127.0.0.0 * 255.0.0.0
lo
default 207.96.96.102 * ppp0
V. Operations
My setup works great! I can initiate a PPP connection to my ISP by
logging into my Linux box, either by walking down the basement, or
telnetting to the Linux box from my Mac. Best of all, thanks to IP
Masquerading, my wife and I can now both use the Internet at the same
time!
With my new LAN setup, my Internet programs (e.g. my web browser) run
slightly faster now because my Mac no longer has to simultaneously
maintain a modem connection and run MacPPP. Further, when I have to
reboot my Mac (yes, it does happen occasionally with Macs) I don't
have to redial my ISP because the connection is maintained by my Linux
box; as soon as I reboot, I'm back online.
VI. Final Comments
Things to Try
I have not tried to optimize the performance of my Mac-Linux LAN.
However, since Ethernet packets can be almost 3 times larger than
LocalTalk packets, one thing to try is to move the burden of reducing
the packet size from the router to the Linux box by reducing the MTU
parameter of the Linux Ethernet interface. (For example, to change the
MTU size to 500, type "ifconfig eth0 mtu 500.") Another interesting
thing to try is IRQTUNE which lets you give the serial port on the
Linux box higher processing priority so that it has less chance of
dropping packets (http://www.best.com/~cae/irqtune). I have not tried
IRQTUNE yet, but it might be a good thing to run for anyone using a
modem with a Linux box.
One of the things I'd like to try is accessing my Linux box using
X-server software on my Mac. I'll have to make sure that the X-server
software can run over LocalTalk.
Summary
This article has described a low cost way of creating a Mac - Linux
network at home. I hope that Mac, DOS, and Linux users have all found
something of interest in the setup I've described.
I would be happy to hear from anyone with comments or questions.
_________________________________________________________________
Copyright © 1998, Dr. Richard L. Dubs
Published in Issue 26 of Linux Gazette, March 1998
_________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
_________________________________________________________________
"Linux Gazette...making Linux just a little more fun!"
_________________________________________________________________
Tcd and Gtcd
by Larry Ayers
_________________________________________________________________
Introduction
CD-players for Linux abound these days, with both curses-based console
programs and X programs available in a variety of degrees of
usefulness, complexity, and polish. There are even command-line
players, though with the current CDROM drives (with their built-in
controls) a player is no longer strictly necessary. The main advantage
of using a dedicated CD-player program is the possibility of using a
database containing titles and track names, as well as play-lists,
auto-repeating and other user conveniences.
Xmcd is one of the more popular X-windows players; it's a freely
available program but does require the proprietary Motif libs for
compilation from source, though statically-linked binaries are
available. One reason for its popularity is the internet database of
CD titles and tracklists which is accessible from within the program.
This database is remarkably complete, and once you start using it only
the most obscure titles should ever have to be entered manually. This
database project has really mushroomed; originally Ti Kan (author of
Xmcd) created the database format for use in his program, and
distributed database files made up of user contributions. The files
began to become excessively large and cumbersome, so the idea of
making them directly accessible via the internet arose. Ti Kan
recruited Steve Scherf to write a protocol which would make possible
quick retrieval of individual queries, and Steve found sites which
agreed to become servers. There are now CDDB servers distributed
across the planet, and the databases are even accessible from behind
firewalls from many HTTP servers. Information on incorporating the
protocol into a CD-player program is available from the cddb website;
this material is freely available, and assistance is offered for
freeware and shareware developers.
Unfortunately, I never have been able to get Xmcd to work consistently
on my system; there is something in the way my ATAPI drive works which
causes problems. Xmcd was originally written with SCSI drives in mind,
and although ATAPI IDE drive support has been added it didn't seem to
care for my drive's peculiarities.
Tcd and Gtcd
I've been using Tim Gerla's simple but useful console-mode player tcd
for several months, and have become quite adept at quickly typing in
disc and track information. Recently Tim introduced a new version. and
after unpacking it I was surprised and pleased to see that not only
had he produced a GTK-based X version, but the program now supports
the CDDB protocol. So one day I was on the internet, downloading some
beta software, and started up the new tcd version. I was playing a
disc which I hadn't entered into the program's database, and I
happened to see a notice on the screen which said "[D] Download CDDB
data". I gave it a try, thinking that it would probably take awhile,
and that the particular CD I was playing probably wasn't even listed.
Within two seconds the title and track data was displayed on the
screen, which startled and impressed me.
This newly released version, 2.0b, is a beta, though I haven't
encountered any but the most minor bugs. The GTK version doubtless
will be revised, as GTK is still under active development. Here's a
screenshot of the interface:
Gtcd
It's a nice-looking interface, with that distinctive GTK look made
familiar by the Gimp. When the CDDB button is clicked a window opens
with the default server and port displayed in entry fields, which can
then be edited depending on your location. A convenient drop-down menu
of track titles (invoked by clicking the Goto button) is a feature not
found on many players.
Most of tcd's features can be found on other X-windows players, though
the only others which are CDDB-enabled (as far as I know) are Xmcd and
the KDE CD-player Kscd, written by Johannes Wuebben. The
last-mentioned is a very usable and well-done application, but
requires the KDE and Qt libraries in order to function. Gtcd only
needs gtk+-0.99.3, which is also needed by the Gimp.
An unusual feature is the existence of both console and X executables
which share the same features, configuration, and database. I use X
about two-thirds of the time, shutting it down when I'm compiling
large applications or just writing in an editor, and it's nice to be
able to use the same CD-player in each environment.
Availability
As I write this, the source and binary distributions are still in the
incoming directory at Sunsite, with the filenames prefixed by
tcd-2.0b; an alternate site is here.
_________________________________________________________________
Copyright © 1998, Larry Ayers
Published in Issue 26 of Linux Gazette, March 1998
_________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
_________________________________________________________________
"Linux Gazette...making Linux just a little more fun!"
_________________________________________________________________
Setting up Your In-Home (or In-Office) Network
By Tom Kunz
_________________________________________________________________
Contents:
* What Does This Article Cover?
* Before You Begin - Have a Working Network!
* Configuring Your Local Network
* Installing diald
* Installing pppd
* Kernel Configuration
* Configuring IP Forwarding Firewall
* Configuring pppd
* Configuring diald
* Setting Time-Outs and Other Options
* Application Notes
* Conclusion
What Does This Article Cover?
Well, this article covers a couple of topics that you've probably seen
discussed before in Linux Gazette and/or Linux Journal. Let's say you
have 2 or more computers, maybe in an office, maybe at home, and you
want to have one of them be the "gateway" for the other(s). If your
ISP charges by the minute (or in 5/10/15 minute increments), which
many of them do for corporate accounts, then you don't want to spend
excessive amounts of time on the line to your ISP. You also don't want
to risk forgetting that you are connected and running up a bill while
doing nothing! So what you want is a way to get your local network
onto and off of the Internet with ease, and with a minimum of
extraneous cost. This includes demand-dialing, IP forwarding, IP
Masquerading, PPP configuration, and some basics of networking. Sounds
like a lot (and believe me, it can be!), but it's not so bad when you
find out that, for the most part, you don't necessarily need all the
power and flexibility that the packages involved in this setup have.
Please note that while I will be detailing how to set up your Internet
gateway in Linux, that does not imply that your entire network needs
to be running Linux. You can have one Linux box acting as the gateway,
while the rest of the network is a mix of other platforms. You can
have any kind of hardware and software on the network, provided that
the systems have a TCP/IP stack. Any mix of DOS, Mac, Win95, or unix
workstation can be applied to a network configured in this way.
This kind of arrangement is extremely useful for a number of reasons.
If WWW browsers are going to be used heavily, this kind of network is
ideal. WWW browsers open transient TCP connections for operation,
which download chunks of information in spurts, usually not remaining
connected for more than a few seconds. While someone reads a web page,
the browser generates no (or very little) network traffic, thus
leaving the connection idle, and allowing someone else to share the
unused bandwidth to full potential. Another reason for installing this
kind of arrangement is so that users don't tie up valuable phone lines
for extended periods. Recently, I installed a similar arrangement for
a small company whose employees were frequently on the Internet from
their PC's, each using their own phone line at their desk. Of the few
and costly phone lines they had, usually half of them were doing
dial-up connections, while the other half could handle voice calls. By
the arrangement that I prescribe here, they limited it to one phone
line, and everybody was able to access the Internet while using the
phone line at their desk for voice.
To describe what I've done here, I'm working from the reference frame
of having installed a fresh copy of Red Hat 4.2, with the option of
installing everything set. From what I've seen, 5.0 isn't incredibly
different (for this stuff, anyway), and I'll also be pointing out the
differences between setting this up on Red Hat and setting this up on
Slackware 3.3.
Before You Begin - Have a Working Network!
First and foremost, I would recommend some other documents for your
perusal before engaging in setting up a working LAN. These would be:
* The Network Administrator's Guide
* Linux System Administrator's Guide
* NET-3-HOWTO, Linux Networking
* Ethernet-HOWTO, the details about ethernet hardware for Linux
In order to set up a home or office network with a dial-up gateway,
you first need to have a local area network (LAN) working correctly. I
would recommend you read over the above documents in some detail as
you attempt to get your network going. The exact type of network card
you use is not important to the discussion of the text, but if asked,
I would recommend ISA cards, either 16- or 8-bit, in order to cut your
teeth on networking. They provide the least hassles and have been well
supported by Linux for years. My personal favorites are the SMC/WD
80*3 cards, but virtually all legacy ISA cards (non-PnP,
jumper-configurable cards) should work. See the documentation listed
above for exact details on making your network run.
Configuring Your Local Network
I will be using the term "Linux gateway" or "gateway" to denote the
machine on your network which will be running Linux and actually have
the modem and will be performing the connections to the outside world
for your network.
Networks for small offices or within a home are generally not in
registered domains. If you are setting up a connection for an office
which is in a registered domain with an IP address which is part of
the Internet (ie, not one of the reserved network numbers for private
use), then you will need to configure your network according to that
registered domain and IP address block which you have been allocated
by InterNIC. If you don't know what I'm talking about, then you want
to use one of the "reserved" network numbers that are set aside for
private usage. The network number which I will use will be
"192.168.1.0", which I have configured for my home usage. Because it's
reserved, I know that all my packets will not conflict with anyone on
the Internet, since all packets destined for reserved addresses are
dropped by your ISP's routers, and the main backbone routers on the
Internet.
Note that the steps I describe here are often done in parallel with
the previous section on "Have a Working Network". Once you've selected
a reserved IP address block for your network, you need to configure
your hardware to be recognized and give the appropriate parameters to
the software. I recommend setting the gateway's address to the ".1"
node number of your network. It's not a law, but it's commonly
accepted and easy to remember. For example, if you are using
192.168.1.0 as your network, then 192.168.1.1 will be your Linux
gateway. Then have the other systems on the network numbered as
192.168.1.2 through 192.168.1.254. Some administrators like to have
their nameserver for the LAN set up as ".254", but if you only have a
few machines on your network, you're not likely to need or want a
nameserver.
Selecting a domain name doesn't deserve a huge amount of thought. It's
just a matter of coming up with something that is easy to remember,
describes your network, and will not conflict with any registered
domain names. The extensions of ".com", ".org", and ".edu", as well as
country abbreviations (".de", ".uk", ".au", etc.) are off-limits. Just
don't use anything that looks like a typical address, and you'll be
ok. For example, my local network at home is the domain of
"kunz.home". There's no domain out there belonging to ".home", so it's
OK. Or if you want to set up an office network for "ACME Inc.", then
you might try "acme.office" as your domain name.
The network parameters can be set up in Linux either while performing
the initial installation or after the installation has been done. If
you decide that you would like to have your gateway named "linux-gw",
and that you want your domain to be "smith.home", you will not have
any conflicts with names outside of your network. If you are using
192.168.1.0 as your network number, then the parameters for networking
should look like this:
* Host Name: linux-gw
* Domain Name: smith.home
* IP Address: 192.168.1.1
* Netmask: 255.255.255.0
* Broadcast: 192.168.1.255
* Default Gateway:
* Primary Nameserver: (IP address of your ISP's primary nameserver)
* Secondary Nameserver: (IP address of your ISP's secondary
nameserver)
* Tertiary Nameserver: (IP address of your ISP's tertiary
nameserver)
Note: Not all TCP/IP implementations will ask for or be configurable
for more than one or two nameservers. Just ignore the "secondary" and
"tertiary" fields if that's the case.
Also, notice that it's important to leave the default gateway empty!
The routing tables will be modified by diald, which will be discussed
later.
On "linux-gw", you should make/edit the /etc/hosts file. It should
contain the IP addresses and names of all the machines on the network.
Let's say you will have 4 machines on the network besides the Linux
gateway. You might, conceivably, have an /etc/hosts file that looks
something like this:
127.0.0.1 localhost localhost.localdomain
192.168.1.1 linux-gw.smith.home linux-gw
192.168.1.2 winchester.smith.home winchester
192.168.1.3 ruger.smith.home ruger
192.168.1.4 browning.smith.home browning
192.168.1.5 mossberg.smith.home mossberg
By doing this, the Linux gateway knows the names of all the machines
on the network. This should also be done on any unix workstations or
other Linux machines you have on the network. On Slackware
installations, you'll need to edit this by hand. On Red Hat, you can
use the "netcfg" program under X to modify the "Hosts" entry.
On each of the other machines in the network, you will need to
configure their parameters as follows. Be sure not to duplicate IP
addresses between different machines! The following sample entry is
for a client on the "smith.home" network named "winchester".
* Host Name: winchester
* Domain Name: smith.home
* IP Address: 192.168.1.2
* Netmask: 255.255.255.0
* Broadcast: 192.168.1.255
* Default Gateway: 192.168.1.1
* Primary Nameserver: (IP address of your ISP's primary nameserver)
* Secondary Nameserver: (IP address of your ISP's secondary
nameserver)
* Tertiary Nameserver: (IP address of your ISP's tertiary
nameserver)
Now, notice basically only one major change: the default gateway. When
any of the machines on the network send out packets, we want them to
route them through 192.168.1.1, which is your Linux gateway. As the
gateway for the rest of the network, Linux will decide where packets
get sent. You should configure all the machines on the network with
the above paramters, changing only the host name and the IP address
for each. Any TCP/IP-capable platform should have the provisions to be
configured as above, save only possibly for the secondary and tertiary
nameserver portion. Note that it's also quite possible that your ISP
will only provide one or two nameservers, and that the third is
unlikely to be filled, most of the time.
If you are configuring a Slackware Linux machine as your gateway after
installation, the appropriate way to change the network parameters is
to run the program "netconfig" as root. You will be prompted for the
network parameters one at a time, and should follow the "linux-gw"
listing above. Under Red Hat, you should run the "netcfg" program from
X while root. This provides a graphical tool for doing the same thing.
Running "control-panel" as root in Red Hat provides an X front-end to
many of the administrative tasks, including networking.
By the time you get this far, you should have a working network, where
you can telnet from any of the machines on your network into the Linux
gateway.
Installing diald
The package that we will be using for performing the automatic
dialling is "diald". This assumes that you have a modem which Linux is
already aware of. If not, you need to consult your installation
documentation and the incredibly useful Linux Resources page
Once you can verify that your modem is working ok and is recognized by
Linux correctly, we can configure diald to do the work for us. As a
note, I would like to say that I've had the least problems with
external modems and with non-PnP modems. These days, it's hard (if
possible at all) to find a non-PnP internal modem. If you absolutely
have to use a PnP modem, then I recommend getting the isapnptools
package for initializing PnP configuration.
First, you need to obtain and install diald. If not already installed
on your system, it's possible to obtain the code from Sunsite. If you
have Red Hat, you can find the binary distribution in RPM format on
your Red Hat 4.2 CDROM. It is located in
/[mountpoint]/RHSCont/i386/diald-0.16-3.i386.rpm. The file
diald-config-0.1-1.i386.rpm is found in the same directory, and I
recommend you install it, since it contains some sample configurations
that may be useful to you. Under Red Hat 5.0, I was unable to find it
on the 2-CDROM distribution set from Red Hat, so the latest version of
diald should be downloaded from Sunsite. The same goes for Slackware.
Download the pacakge and follow the build instructions included. [LG
HTML note: if you find those links are broken by the time you read
this, you should be able to browse
http://www.sunsite.unc.edu/pub/Linux/system/network/serial/ to find
the current version of diald]
Installing pppd
Once you have diald installed, we need to install pppd. This comes up
in both Slackware and Red Hat 4.2/5.0 as packages that are selected
for installation if you install everything. If it is not installed, it
can be found on your Red Hat 4.2 CD in
/[mountpoint]/RedHat/RPMS/ppp-2.2.0f-3.i386.rpm. If you have RedHat
5.0, you will find it on the first CD of the set, in
/[mountpoint]/RedHat/RPMS/ppp-2.2.0f-5.i386.rpm. Slackware contains
the ppp.tgz package at or around floppy N3 or
/[mountpoint]/slakware/n3. If you don't have it installed on your
Linux gateway already, you may need to download the source for it from
Sunsite. Basically, just follow the build instructions and install it
via the Makefile.
Kernel Configuration
Now you have diald and pppd installed, but you may not have any
support for IP Masquerading, which is an absolute MUST for this kind
of networking scheme. If you are using a stock Red Hat 5.0 kernel, you
will be fine, as just about everything is compiled as a module. IP
forwarding will be provided on-demand by kernel module loader, as long
as you have modified /etc/sysconfig/network (see "Configuring IP
Forwarding Firewall", below). If you're using a stock kernel that came
with Slackware, you probably don't have support for the IP
Masquerading ready. If you installed everything as I recommend in the
beginning, you'll have the kernel sources already on your Linux
gateway. But if not, you can download the source code for kernel
2.0.33 from Sunsite. Be patient! It's a 6M file!
Just untar it in your /usr/src directory, and the do the following:
1. cd /usr/src/linux
2. If you are in X, type "make xconfig". Otherwise, just "make
config".
3. You will need to set several options in the "Networking Options"
section of the configuration. You should say "Y" to:
+ Network firewalls
+ TCP/IP networking
+ IP: forwarding/gatewaying
+ IP: firewalling
+ IP: masquerading
+ IP: ICMP masquerading
4. Note that you need not configure any of the logging/accounting
features. Most users won't need that. Only configure it if you
know why you are doing it. I won't mention anything substantial
about accounting or logging features in this article.
5. When you've configured all your hardware the way it should be, you
will want to click on "Save & Exit" if you're running "make
xconfig". If you need help determining how your kernel should be
set up, you need to consult the resources at Linux Resources to
find out how to best compile your kernel to support all your
hardware correctly.
6. If you are reasonably certain your kernel configuration is
correct, you will type in "make dep ; make clean ; make zlilo". If
you are compiling in loadable module support for certain items,
you will want to also do "make modules ; make modules_install"
after "make zlilo" finishes. If "make zlilo" finishes with saying
something about the kernel being too big (usually a result of
trying to compile too many drivers into the kernel directly,
rather than as modules), then you will want to try "make bzlilo",
which allows for larger kernel.
7. When you complete the previous step, you will want to reboot the
machine so that the new kernel can take over. Provided you
configured your kernel correctly, you'll be booting up a system
capable of IP forwarding and masquerading!
Configuring IP Forwarding Firewall
The next step along the path to having a Linux machine that can act as
a gateway to the Internet is to configure IP forwarding. IP forwarding
can be a very complicated and involved thing, however, to act as a
simple gateway and firewall to the Internet, all we need to do is
configure the forwarding rules so that packets of all types found on
the ethernet interface are copied onto ppp interface.
Please be aware that you should be fully informed of the security
concerns of this. I recommend that you read some materials on
security, keep a copy of SATAN handy, and consult some security
experts if you worry about security. If you have a dial-up service to
a local ISP, there is a lower probability that you will be hacked on
than if you are using a university as your ISP. College kids aren't
necessarily malicious, but they can be deemed a security risk, as they
are usually more "inquisitive" than the typical Windoze 95 user at
home who happens to be a customer of your local ISP. Don't take me as
Gospel Truth, check into it for yourself and find out the issues about
security if it is something you want to know about.
The first thing to have is the ipfwadm package installed on your
system. If you have it already installed and your kernel has been
compiled in the previous step to support packet forwarding, then
you're set, and you can move onto the actual configuration of the
firewall. If you are using Red Hat 4.2, the package can be found at
/[mountpoint]/RedHat/RPMS/ipfwadm-2.3.0-2.i386.rpm. If you are using
Red Hat 5.0, you should find it on the first CD of the set, in
/[mountpoint]/RedHat/RPMS/ipfwadm-2.3.0-5.i386.rpm. If you're using
Red Hat, you will note that you'll also have to modify the file
/etc/sysconfig/network, making the line containing "FORWARD_IPV4" to
say "FOWARD_IPV4=true". For Slackware, you should find installed in
the base TCP/IP package (N6, "tcpip.tgz"), so if you have TCP/IP
networking installed, it should already be there. If you need to
download it, the source can be found at its home page.
Once you have the package installed, you need to know how to use it!
Depending on how secure you would like it to be, you can make a few
changes to what I have here. What you want to do is flush the table of
all previous firewall forwarding entries, set a default policy for
either accepting or rejecting packets, and then tell it how to forward
packets between different interfaces. For example, the following
script will flush all forwarding rules, set the default policy to
"accept" packets, and will forward packets between all of the
available interfaces:
#!/bin/sh
ipfwadm -F -f
ipfwadm -F -p accept
ipfwadm -F -a m -S 192.168.1.0/24 -D 0.0.0.0/0
We can view the IP forwarding rules by issuing the command "ipfwadm -F
-l -n", which will list the rules numerically. If we do that, we will
get output looking like this:
IP firewall forward rules, default policy: accept
type prot source destination ports
acc/m all 192.168.1.0/24 0.0.0.0/0 n/a
This tells us that any packets going from our network to anything
other than just our network will be forwarded between all of the
interfaces. Now, if we specify an additional "-e" option to the
previous command, we get extended output of the forwarding rules. This
is to our advantage, but you should have a 132 character wide screen
when you run it. Here is a sample output:
IP firewall forward rules, default policy: accept
pkts bytes type prot opt tosa tosx ifname ifaddress source
destination ports
113 9452 acc/m all ---- 0xFF 0x00 any any
192.168.1.0/24 anywhere n/a
Thus, we can see that even though IP forwarding can be incredibly
complicated and selective, we can write a simple script which will do
all the work for us and establish a forwarding firewall.
If you read the manpage for ipfwadm, you will find that the -W option
may be used to specified. For simple situations and a simple network
in a generally trusted environment, the -W option isn't necessary,
because you are probably interested in having all interfaces able to
see all packets. However, if you are interested in keeping certain
interfaces from receiving packets, you may use the -W option for
security.
Configuring pppd
The first thing we want to do is configure pppd, because it's often
easier to test out than diald. To do this, we want to create a chat
script, which will dialog with the ISP, and establish the connection.
You will want to read the man page for "chat" first, but here is an
example of a chat script I use:
REPORT CONNECT ABORT BUSY '' atdt5551212 CONNECT '' : tkunz : PaSsWoRd
action ppp
>From the manpage:
This sequence will expect nothing; and then send the
string ATDT5551212 to dial the telephone. The expected
string is CONNECT. If the string CONNECT is received the
remainder of the script is executed. In addition the pro-
gram will write to the expect-file the string "CONNECT"
plus any characters which follow it such as the connection
rate.
First, the script will report what the modem returns after "CONNECT"
into the report file, to be analyzed later, in order to diagnose what
could have gone wrong with the dial-up. The ABORT string means to
abort the script should it see the "BUSY" string returned by the
modem. After that, this script will diald "555-1212" as the phone
number, and wait for the CONNECT message to come back from the remote
end. It will then wait for a colon (":"), and reply with "tkunz". It
will wait for another color (":"), and reply with "PaSsWoRd". When the
string "action" is received from the remote end, it replies with "ppp"
and the chat script terminates. Chat will then pass control back to
the program that called it. But here's another script that will work
fine, provided we don't need the "REPORT" error checking, and we don't
ever expect to get a busy signal:
atz OK atdt5551212 CONNECT name: tkunz word: PaSsWoRd action: ppp
This one will do the same thing, only it will initialize the modem to
the default setting by issuing "atz" first, and instead of expecting
only a colon, it waits for "name:" and "word:" to be received before
issuing "tkunz" and "PaSsWoRd", respectively, to the remote end.
These simple one-line scripts like the above examples can be used with
chat to automate the login procedure with your ISP.
pppd uses chat to establish a connection, and then when chat
terminates, pppd continues to dialog with the remote end, determining
its local and remote IP addresses, and then pppd follows the other
command line options to secure a reliable connection.
To give you an idea of what a set of scripts would look like that
starts a PPP connection, here is a sample of something I use to
manually bring up a PPP connection to my ISP.
The contents of a file in my own directory, named "startppp":
#!/bin/sh
/usr/sbin/pppd /dev/cua3 115200 connect 'chat -f /etc/ppp/chatscript'
defaultroute crtscts proxyarp passive
This tells pppd to use my modem, located on /dev/cua3 (COM4 in DOS),
at a speed of 115200, which my 33.6kbps modem can handle. The
"connect" parameter says to use the next quoted string as the
command-line which will connect pppd to the remote host.
* Note to programmers: pppd connects its stdin and stdout to the
stdin and stdout of the command-line specified by the "connect"
option. This is good to know, if chat doesn't work with your
modem. This is often the case with PCMCIA modems or some
non-standard modems, so you might decide to write a shell script
incorporating "expect" and/or other text utilities, or a Perl
script that does the same. A chat replacement is only required to
use stdin and stdout to dialog with the remote end and then exit
by returning 0. See the "chat" manpage for more details on
termination codes.
The option "defaultroute" tells pppd to modify the routing tables so
that this connection is added as a default route to the rest of the
world. The "crtscts" option tells pppd to use hardware flow control
for the modem, a MUST for modems faster than about 9600 baud.
"proxyarp" says to add an ARP entry for the local and remote systems
to the ARP table. The "passive" option tells pppd to be patient about
receiving LCP packets from the ISP. If pppd does not immediately
receive an LCP packet from the remote end, it drops carrier. I have
personally found this to be the "magic ingredient" to getting pppd
working with several different ISP's. The contents of the file
/etc/ppp/chatscript, used by "chat" in "startppp":
REPORT CONNECT ABORT BUSY '' atdt5551212 CONNECT '' : tkunz : PaSsWoRd
action ppp
Substitute in your login name, password, and the command which starts
ppp (if any) for the appropriate fields in the /etc/ppp/chatscript,
and see what happens. You may need to contact your ISP if you have
never used pppd in Linux before to establish a PPP connection, to
determine if there are specific options necessary to make and sustain
a PPP connection. You can try the above script and then watch the
/var/log/messages file to see what happens. You might need to modify
your /etc/syslog.conf file to get the messages printed to the right
location if you use Red Hat. I prefer a slightly modified Slackware
/etc/syslog.conf, which is shown here:
# /etc/syslog.conf
# Very Important! All whitespace are TABs, not " " (space) characters!
#
*.=info;*.=notice /var/log/messages
*.=debug /var/log/debug
*.warn /var/log/syslog
After making this your syslog.conf file, you can do a "touch" on
/var/log/messages, /var/log/debug, and /var/log/syslog, restart
syslogd and watch the messages appear. Occaisonally, I've noticed
strangeness with syslogd not wanting to give up the previous
configuration, so you might find a reboot rather than just a restart
of syslogd is in order.
Once you have syslogd logging the right level of messages to the
locations mentioned above, you can watch the progress of pppd from one
window or virtual console while you execute "startppp" from another.
By watching /var/log/messages (and possibly by watching the modem
lights if you have an external modem), you can determine if chat
succeeded or failed, or if the right options were specified to pppd.
As root, the command "tail -f /var/log/messages" will enable you to
see messages as they are dumped into /var/log/messages.
By experimentation, you should be able to get a PPP connection started
by using these scripts and commands. Again, I mention that you might
have to call your ISP to find out if any special LCP or IPCP options
need to be set.
Configuring diald
By this time, you should be able to regularly initiate a PPP link to
your ISP by executing "startppp", and you should be able to use web
browsers and the like to get onto the Internet from the other machines
on the network once you have the IP forwarding rules installed. The
next peice of the puzzle is diald. diald is designed as a
demand-dialer, meaning that when it senses that you want to get from
the local network out onto the Internet, it dials your ISP and sets up
the connection for you.
The first thing to realize is that we are going to have to change the
way we think about pppd and chat for the moment. Before, in our
previous script in the section about configuring pppd, we had pppd
start up, then issue the "connect" command. After that occurred, pppd
would run according to the options we put on the command line. In
diald, we have to recognize that diald will be handling many of the
details that pppd handled before. These details include the dialing
script and options that would normally be passed to pppd. diald will
be responsible for implementing these things now, not pppd.
What diald does is it creates a "virtual" interface, sl0, which is a
slip interface to nowhere. We will have it assign the IP address of
192.168.0.1 to sl0, and an IP address of 192.168.0.2 to the remote end
(basically nothing!) of the fake slip interface. Then it creates a
route so that traffic not intended for the local network will go into
sl0. When diald finds packets being copied onto sl0, it realizes that
those packets should go into the Internat, and starts the dialing
process. In order to make our particular network arrangement work, we
have to set up the IP forwarding to be promiscuous, in a sense, in
that it forwards between all interfaces, including sl0. Thus, packets
which are generated by one of the other machines on the network will
go into the Linux gateway, the IP forwarding mechanism will copy them
onto the sl0 interface if they are not destined for only the local
network, and then diald will take over, starting the dialing process
and pppd to bring up the link.
The manpage of diald-examples should have been installed on your
system when you installed it. If you read that, you will probably find
your own situation there in the manpage, however, most of you will
probably find that it corresponds with the section named "A Leaf Node
with Dynamic Local Address using PPP". The following comes directly
from the diald-examples(5) manpage for this situation:
mode ppp
connect /etc/diald/connect
device /dev/ttyS1
speed 115200
modem
lock
crtscts
local 192.168.0.1
remote 192.168.0.2
dynamic
defaultroute
include /usr/lib/diald/standard.filter
To start off with, you should have the above as your initial
/etc/diald.conf file. We will add options to it later. At this point,
please understand that diald has to know exactly where to find the
external programs of route, ifconfig, and pppd. This article assumes
that you have installed pppd, ifconfig, and route into their default
locations, which are:
/usr/sbin/pppd
/sbin/ifconfig
/sbin/route
If for some reason you do not have them installed in the above
locations, please make links or move them to the appropriate
locations.
Now we come to the part where we modify that initial /etc/diald.conf
file. First of all, we have created a working chat script in an
earlier part of this article, "Configuring pppd". Using that
information, we modify the lines starting with "connect ...", "device
..." and "speed ..." to reflect your configuration. If you followed my
directions exactly in "Configuring pppd" and have a 33.6kbps modem on
COM4 like I do, then you would get a diald.conf that looks like this:
mode ppp
connect "chat -f /etc/ppp/chatscript"
device /dev/cua3
speed 115200
modem
lock
crtscts
local 192.168.0.1
remote 192.168.0.2
dynamic
defaultroute
include /usr/lib/diald/standard.filter
Note that if you have a 28.8k, 33.6k, or 56k modem, your "speed ..."
line will look the same. If you're using a 14.4k, you'll most likely
have to use "speed 57600". Also, make sure you use the correct number
of the COM port. COM ports in DOS are one higher than the appropriate
cua number, since DOS starts numbering from "1" and unix tends to
number things starting from "0".
One thing to note about the diald.conf file is the set of options
which would normally have been specified to pppd. According to the
diald manpage, you must not specify those as direct options to pppd.
This is one of those details handled only by diald. In our original
"startppp" script, we specified "... defaultroute crtscts proxyarp
passive". In our new situation, using diald instead of pppd to
manipulate those options, we need to set those here in diald.conf. All
but the "passive" option can be specified. Thus, we get a diald.conf
that looks like this:
mode ppp
connect "chat -f /etc/ppp/chatscript"
device /dev/cua3
speed 115200
modem
lock
crtscts
local 192.168.0.1
remote 192.168.0.2
dynamic
defaultroute
proxyarp
include /usr/lib/diald/standard.filter
If we need to add the "passive" command to pppd to make it work with
your ISP correctly, then we can insert a new line into the above of
the form:
pppd-options passive
The above diald.conf should get you started with a working connection
to your ISP. If not, you may need to consult your ISP's technical
support line to find out what they recommend.
At this point, you should be able to start diald and watch the
messages in /var/log/messages appear which it generates upon start-up.
After diald starts, you should also be able to send packets from other
nodes of your network to the Internet, and then watch as diald
automatically dials out and establishes a connection. If not, go back
over the previous steps to find out what went wrong.
Setting Time-Outs and Other Options
A very useful feature of diald is its ability to detect inactivity,
and then bring down the ppp link appropriately after a user-specified
amount of time. If you have a single phone line in your home, which
you need to use only in short spurts for dialing out, you'll enjoy
this feature. Or if you're a corporate entity who is charged on
5/10/15 minute increments, you can be sure that the link will go down
after a certain time of inactivity, keeping costs low.
There are also important variables which are not associated with the
link uptime itself, but with the time that different portions of diald
take to execute or time-out. For example, if dialing your ISP and
passing the username, password and related actions take more than 60
seconds, typically, you will want to add a line to the file that says
something like:
connect-timeout 120
Or, if you wish to have diald attempt a redial 10 times before giving
up and only wait 15 seconds to clear the modem between dials, you will
want to add in the following two lines:
retry-count 10
redial-timeout 15
You may also wish to play with some of the other options that diald
has to offer. For example, one option that can be useful is "two-way".
This tells diald that if carrier is dropped while in operation, that
it will not retry dialing. What good is that? Well, if you have to
forcibly terminate the PPP connection to your ISP (killing off pppd
manually to free the line, physically pulling the phone line
connection, etc.) diald will not try to outsmart you and dial again.
If you have a somewhat dedicated line, and you are not concerned about
how long you are connected to your ISP, you won't need that option
very much, as you'll probably stay connected for longer periods of
time.
If you are concerned with accounting for the time that is spent
online, then you will want to play with the "accounting-log ..."
option. The parameter to "accounting-log" should be the full pathname
of a file which will log the times when the link comes up and goes
down, and how much data was sent down the wire. But I said I wouldn't
spend any time talking about accounting and logging ...
The diald manpage is rich with options, and I would recommend that you
read it in parallel with reading this article. Diald is wonderfully
configurable, and can meet a wide variety of needs, depending on how
complex of an arrangement you wish.
Application Notes
OK! Now you can go to any node of your network, start up {Netscape,
IE, Arena, Mosaic, any browser} and get to somewhere out on the rest
of the Internet. However, why does it seem like sometimes your Linux
gateway almost randomly fires up a connection? What's it doing?
Well, now you need to delve into the particular applications on your
network and how they're configured. Two of the big things to check are
mail client and web browsers which contain mail clients. If your mail
client makes requests for new mail, it will generate a packet which
goes to your gateway, and initiates a call. This means that while the
Internet connection is down, someone with a mail client up and running
somewhere on your local network can unwittingly cause the gateway to
establish a connection. This can be annoying and/or costly, both for
the typical home user and the corporation. I know that I've
accidentally done this to my wife on a number of occaisons, where my
gateway attempted to dial out while she was on the phone with someone!
(But she's a wonderful, patient, forgiving wife.)
To fix this, what you need to do is to inform your staff (or family)
that once they finish with their mail client, they should terminate it
immediately. And they should also be informed that they should turn
off the automatic mail-fetching for any mail client that they use,
especially if you are billed for connection time to your ISP or per
minute of call (European countries often bill for even local calls).
Another thing to watch out for is the /etc/resolv.conf on the unix
hosts on your network. You must not have any nameservers which are
outside of your local network listed in it, or else every application
that accepts a hostname will generate packets and cause your gateway
to dial out. For this reason, it's wise to keep every hostname your
local network needs in /etc/hosts on each unix machine. If your local
network is large enough to warrant the effort, you might also set up
your own local nameserver to handle the name requests. A local
nameserver with its own maps for the local domain, and a caching
nameserver for outside requests is probably the most efficient way of
handling that. If you are going to be using a local mail agent like
sendmail, then you will want to be sure to configure it in such a way
that it will not cause the gateway to dial-up the ISP at every
instance of outgoing mail. You'll want it spooled until a connection
is available, or at a routinely scheduled time when all queued mail
will be transmitted out.
Obviously, this document is not going to go into any detail about how
to configure the various applications on your network around using a
demand-dialed gateway. It is useful, however, to be aware of some of
the issues you will face when you add different applications and
platforms to your network, and why things may not be going the way you
initially supposed they would. If you are faced with a larger network
which requires greater upkeep in order to keep it working right, and
high bandwidth to the Internet on a regular basis, it may be time to
consider investing in faster connections (ISDN, T1, T3, OC3, etc.) and
leased lines which better suit your needs. Note that diald can work
with ISDN, but in a larger-scale network with higher bandwidth
demands, a full-time connection may be the best solution.
Conclusion
Well, it's seems apropriate to say that configuring a small network
with demand dialing via diald is a task which can be quite involved,
depending on the complexity of your network. But if you have fairly
"ordinary" needs, you can follow the above procedures to get a working
and reliable demand-dialed connection. Many, at this point, will say
"Well, what are 'ordinary needs' anyway?" or "How big of a network
will this support?". The answer is subjective, however I can say with
reasonable certainty that a network of 2 to 8 machines, each running
their own web browsers, mail clients, and the like, will be quite
adequate over even a 28.8kbps modem. The connection I get to my local
ISP rarely gets past 28.8kbps on my 33.6kbps modem, because of the
lines in my area, and often drops down to 21.6kbps or so, yet I still
get reasonably quick response from having 2 or 3 machines accessing
the Internet simultaneously. If you lust for speed, then you will do
well to get a 56kbps modem, and a line to your ISP that can sustain
56kbps (yes, 53k download by FCC law). From my experience, diald will
have no trouble with a 56kbps, provided it is either external and
connected to a 16550 UART, or if you have built some version of a PnP
configuration manager which can reliably configure an internal 56k
modem.
_________________________________________________________________
Copyright © 1998, Tom Kunz
Published in Issue 26 of Linux Gazette, March 1998
_________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
_________________________________________________________________
"Linux Gazette...making Linux just a little more fun!"
_________________________________________________________________
The Yorick Programming Language
By Cary O'Brien
_________________________________________________________________
Contents:
* 1. Introduction
* 2. Basic operations
* 3. Advanced Array Operations
* 4. Graphics Operations
* 5. Closing Remarks
* 6. Additional Resources
_________________________________________________________________
1. Introduction
Linux leverages a vast amount of academic software, either easy ports
of existing Unix packages, or increasingly in recent years software
that is already ready to run under Linux.
One example is Yorick, and this article is an attempt to provide a
brief overview of the nature and capabilities of this system.
Yorick is not just another calculator -- readable syntax, array
notation, and powerful IO and graphics capabilities make Yorick a
favorite tool for scientific numerical analysis. Machine-independent
IO, using the standard NetCDF file formats, simplifies moving
applications between hardware architectures.
Yorick is an interpreted language for numerical analysis, developed at
Livermore Labs by David H. Munro. Implemented in C, it is freely
distributed under a liberal copyright. Yorick runs on a vast range of
machines, from 486SX Linux Laptops (in my case) to Cray YMP
supercomputers.
Who uses Yorick? The majority of users are physicists, many with
access to the most powerful computers in the world. Specific
applications include Astrophysics, Astronomy, Neurosciences, Medical
Image Processing and Fusion Research.
In this article I will discuss the basics of running Yorick, describe
the key array operations, and briefly discuss array operations,
programming, and graphics. I hope that this quick look is enough to
get the more mathematically inclined of you to give Yorick a try.
_________________________________________________________________
2. Basic operations.
When invoked without arguments, Yorick presents a typical command line
interface. Expressions are evaluated immediately, and the result is
displayed. Primitive types include integers, floating point values,
and strings, and all the built-in functions and constants you would
expect are present.
Variable names are unadorned -- no leading $, and need not be
pre-declared, and C style comments are supported.
Arrays
One might not expect an interpreted language to be suitable for
numerical analysis -- and indeed this would be the case if arrays were
not built into the language. Arrays are first-class objects that can
be operated on with a single operation. Since the virtual machine
understands arrays, it can apply optimized compiled subroutines to
array operations eliminating the speed penalty of the interpreter.
Arrays can be created explicitly:
> a1 = [1.1, 1.2, 1.3, 1.4, 1,5]
And elements can be accessed singly or as a subset, with 1 being the
origin. Parenthesis indicate the indexing operation, and a single
index or a range of indexes can be specified.
> a1 [1.1,1.2,1.3,1.4,1,5] > a1(2) 1.2 > a1(1:3) [1.1,1.2,1.3]
Since array operations are built into the language, functions applied
to the array are automatically applied to all elements at once.
> sqrt(a1) [1.04881,1.09545,1.14018,1.18322,1,2.23607]
Arrays are not limited in dimension. The rank (number of indices) of
an array is not limited to one (a vector) or two (a matrix), but can
be as large as desired. Arrays of rank 3 can be used to represent the
distribution of a parameter across a volume, and an array of rank 4
could model this over time.
Online Help
Yorick also provides a simple but effective help system. Executing the
help command describes the help system. Executing it with a command
name as an argument provides information on that command.
3. Programming
Yorick provides a complete programming language that closely matches C
in terms of control flow, expressions, and variable usage. For
example,
> for(i=1; i<10; i++) { print,1<<i; }
print the powers of two just as you would expect, and function
declarations, introduced with func, work as expected.
> func csc(x) { > return 1/sin(x); > }
There are differences -- variables need not be declared, and arrays
are much more powerful than C. The major difference is in function
invocation. Passing arguments to a function in parenthesis causes an
evaluation and printing of the result, however passing arguments
separated by commas simply executes the function and does not return
the result. Since in most cases intermediate results are not required,
many scripts contain function calls of the form f,x,y rather than the
more familiar f(x,y).
Having a programming language close to C allows easy migration between
Yorick for prototyping and C for final implementation. However, as
several Yorick users have indicated, moving to C was often unnecessary
-- the Yorick program proved to be fast enough to get the job done,
and with a minimum of programming effort.
If C extensions are required, a straightforward framework allows
extending the Yorick command language with whatever new operations are
necessary.
_________________________________________________________________
3. Advanced Array Operations
Now things get really interesting. Yorick has a compact and
sophisticated mechanism for describing array indexing and operations,
which are used to precisely specify the desired operation to the
interpreter.
As you recall, applying an operation to an array causes the operation
to be applied to each element of the array. For example
a = [1,2,3,4,5]
sqrt(a)
[1,1.41421,1.73205,2,2.23607]
But what about multiplying two vectors? The default is to perform an
element by element by multiplication.
b = [2,4,6,8,10]
a*b
[2,8,18,32,50]
But those of you that remember physics or linear algebra will recall
the inner and outer products. The inner product is defined as the sum
of the pairwise products:
a(+)*b(+)
110
And the outer product creates a matrix out of each possible
multiplication
a(-,)*b(,-)
[[2,4,6,8,10],
[4,8,12,16,20],
[6,12,18,24,30],
[8,16,24,32,40],
[10,20,30,40,50]]
The + and - symbols used where an index would be are called
special-subscripts, and provide precise control over how array
operations are executed.
The + is the matrix multiplication pseudo-index, which indicates to
Yorick along which dimension the addition part of a matrix multiply
should be performed.
The - is a pseudo-index, creating an index where one did not exist
before. Rank-Reducing Operators:
The operators sum, min, max, and avg can be used in place of indexes.
a(max)
5
b(avg)
6
One might wonder why this is necessary, when the equivalent functional
operators (i.e. min() or avg()) exist? The reason is that for matrices
of rank more than one, the rank-reducing index operators allow you to
specify exactly how to perform the operation. For example, given a 3x3
array, to you want to average across rows, columns, or the entire
array?
c = [[1,2,3],[4,5,6],[7,8,9]]
dimsof(c)
[2,3,3]
avg(c)
5
c(avg,avg)
5
c(avg,)
[2,5,8]
c(,avg)
[4,5,6]
Here we have also introduced the dimsof() operator, which reports the
dimensions of the argument. In this case the result tells us that c is
an array of rank 2, with 3 elements in each direction.
_________________________________________________________________
4. Graphics Operations
Under Linux, Yorick is linked with the GIST graphics subsystem,
allowing immediate display of plots and diagrams. Plots are
interactive, allowing the user to zoom in and out, stretch axes, and
crop the displays using the mouse. Yorick is capable of displaying
sequences of plots over time as a move, and because of this the
command to prepare for a new image is fma, or frame advance. Onward.
To plot the value of a function at evenly spaced points we need to
first create the x values.
x = span(0,10,256)
dimsof(x)
[1,256]
X is now a 256 element long array with values that range from 0 to 10.
The plg function, given vectors for the x and y values, plots x-y
graphs.
plg, sin(x^2), x
The result is shown in plot 1. Note that the arguments are supplied
y,x (not x,y). This allows Yorick to supply a default x vector
(ranging from 1 to the number of y points) if desired.
Parametric plots are also supported. Consider the following:
window, style="vgbox.gs"
a = span(0,20,256)
x = a * sin(a)
y = a * cos(a)
plg, y, x
This produces the spiral in plot 2. The style of the plot has also
been changed.
Surface plots are also available, either as a wire frame
#include "plwf.i"
orient3
x = span(-pi,pi,32)(,-:1:32)
y = transpose(x)
fma
plwf, sin(x)*cos(y)
Or a shaded surface rendition:
fma
plwf, sin(x)*cos(y), shade=1, edges=0
A host of advanced graphics options are used in the demonstration
programs distributed with Yorick, and the latest copy of the
documentation has an extensive description of graphics options. In
addition, libraries to read, write, and display PNM format images is
provided.
_________________________________________________________________
5. Closing Remarks
Yorick is an exceptionally rich environment for numerical analysis.
Many capabilities such as file IO, debugging, animation, and
distributed operation using MPY have been omitted. If you are at all
interested please take the time to read through the documentation and
the example programs. You will not be disappointed.
_________________________________________________________________
6. Additional Resources
Yorick Home Page:
ftp://ftp-icf.llnl.gov/pub/Yorick/yorick-ad.html
Yorick Archive Sites:
ftp://sunsite.unc.edu/pub/Linux/apps/math/matrix/yorick-1.4.src.tar.gz
Linux Software for Scientists (and Curious Layfolk):
http://www-ocean.tamu.edu/~baum/linuxlist.html
Scientific Applications under Linux:
http://SAL.KachineTech.COM/
_________________________________________________________________
Copyright © 1998, Cary O'Brien
Published in Issue 26 of Linux Gazette, March 1998
_________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back Next
_________________________________________________________________
Linux Gazette Back Page
Copyright © 1998 Specialized Systems Consultants, Inc.
For information regarding copying and distribution of this material see the
Copying License.
_________________________________________________________________
Contents:
* About This Month's Authors
* Not Linux
_________________________________________________________________
About This Month's Authors
_________________________________________________________________
Larry Ayers
Larry Ayers lives on a small farm in northern Missouri, where he is
currently engaged in building a timber-frame house for his family. He
operates a portable band-saw mill, does general woodworking, plays the
fiddle and searches for rare prairie plants, as well as growing
shiitake mushrooms. He is also struggling with configuring a Usenet
news server for his local ISP.
Jim Dennis
Jim Dennis is the proprietor of Starshine Technical Services. His
professional experience includes work in the technical support,
quality assurance, and information services (MIS) departments of
software companies like Quarterdeck, Symantec/ Peter Norton Group, and
McAfee Associates -- as well as positions (field service rep) with
smaller VAR's. He's been using Linux since version 0.99p10 and is an
active participant on an ever-changing list of mailing lists and
newsgroups. He's just started collaborating on the 2nd Edition for a
book on Unix systems administration. Jim is an avid science fiction
fan -- and was married at the World Science Fiction Convention in
Anaheim.
Dr. Richard L. Dubs
When Dr. Dubs is not playing with Linux, he is a Senior Scientist with
a Virginia-based defense contractor. He lives in an idyllic community
in Rockville, MD with his wife, two kids and the family cat.
Michael J. Hammel
Michael J. Hammel, is a transient software engineer with a background
in everything from data communications to GUI development to
Interactive Cable systems--all based in Unix. His interests outside of
computers include 5K/10K races, skiing, Thai food and gardening. He
suggests if you have any serious interest in finding out more about
him, you visit his home pages at http://www.csn.net/~mjhammel. You'll
find out more there than you really wanted to know.
Tom Kunz
Tom is 24 years old, married to the most wonderful woman in the world,
and he works as a Systems Programmer for Rutgers University
Telecommunications Division. Hobbies, other than Linux, include
listening to and performing classical/romantic-period piano music,
writing piano arrangements for church, woodworking, and recreational
shooting. I can be reached at tkunz@hardees.rutgers.edu or
tkunz@fast.net.
Mike List
Mike List is a father of four teenagers, musician, and recently
reformed technophobe, who has been into computers since April,1996,
and Linux since July.
Eric Marsden
Eric is studying computer science in Toulouse, France, and is a member
of the local Linux Users Group. He enjoys programming, cycling and Led
Zeppelin. He admits to once having owned a Macintosh, but denies any
connection with the the Eric Conspiracy Secret Labs.
Cary O'Brien
Cary O'Brien lives in Washington DC, and refers to himself, when
pressed, as a "systems engineer". He is currently Vice President of
Optim Systems, Inc., which provides products and services to the the
telecommunications industry. He has been messing with computer
hardware and software since high school. He is married with two
children, 4 and 7, who are starting with computers even earlier.
Alessandro Usseglio Viretta
Alessandro, European citizen and physicist, is a Ph.D. student at the
Swiss Federal Institute of Technology in Zurich. During daytime he's
trying to learn the art of cryo-electron-microscopy but at night he
turns himself into the abominable kernel-compiler.
_________________________________________________________________
Not Linux
_________________________________________________________________
Thanks to all our authors, not just the ones above, but also those who
wrote giving us their tips and tricks and making suggestions. Thanks
also to our new mirror sites.
Lots of excitement in the air these days what with free Netscape and
the debate over OpenSource. We're going through some interesting
times.
Well, not much to report this montho on a personal front--work! work!
work! makes Margie a dull woman.
Have fun!
_________________________________________________________________
Marjorie L. Richardson
Editor, Linux Gazette, gazette@ssc.com
_________________________________________________________________
[ TABLE OF CONTENTS ] [ FRONT PAGE ] Back
_________________________________________________________________
Linux Gazette Issue 26, March 1998, http://www.linuxgazette.com
This page written and maintained by the Editor of Linux Gazette,
gazette@ssc.com