to complete a filename, you can use ESC, @ to
complete a hostname (if it is in /etc/hosts) and CTRL-X, @ to list all possible
hostname completions based on /etc/hosts.
Re: xdm and depth
Date: Tue, 12 May 1998 11:32:26 +0100 (IST)
From: Caolan McNamara,
Caolan.McNamara@ul.ie
From: Denny Åberg, Denny@ele.kth.se
Hi, I'm tired of starting my X-session with 'startx -- -bpp 16' to get 16
biplanes instead of the default 8. How do I get
xdm to run with 16 bpp? If I use it now, it starts X with 8bpp on my Red Hat 5
installation.
under redhat in the file
/etc/X11/xdm/Xservers
there's a line
:0 local /usr/X11R6/bin/X
change this to
:0 local /usr/X11R6/bin/X -bpp 16D
and ta-da, thats it.
Caolan McNamara
Re: Shutdown and Root
Date: Mon, 11 May 1998 13:42:44 +0200
From: Aaron Digulla,
digulla@wi-pc44.fh-konstanz.de
Another note to the 2cents Tip "Re: Shutdown and Root":
I have a shutdown user, too, and this is what he looks like:
In /etc/passwd:
shutdown:x:6:0:shutdown:/home/shutdown:/bin/sh
You'll probably have to adjust the user-id (here: 6).
Then you create a home-dir which just contains this script as
.profile:
------------------------ .profile ---------------------------------------
#!/bin/sh
trap "" SIGKILL SIGINT SIGQUIT
PATH=/bin
# List all users which are still logged on
/usr/bin/finger
echo
echo "Really shut down (y/N) ?"
read answer
# Every answer except "y" is no
if [ "x$answer" != xy ]; then
answer=n
fi
if [ $answer = y ]; then
echo 'The system will now shut down. You can turn the power'
echo 'off when the message "System halted" appears'
/bin/sleep 5
./halt
else
echo 'Abgebrochen...'
/bin/sleep 1
fi
------------------------ .profile ---------------------------------------
Now just copy /sbin/halt to /home/shutdown/ and make it executable
for this user (chown shutdown halt and chmod 700 halt).
Aaron "Optimizer" Digulla
Printing with Linux
Date: Sat, 09 May 1998 18:50:06 +1000
From: Mitch Davis,
mjd@alphalink.com.au
To: AFAIZ@cstp.umkc.edu
I've just bought a HP DeskJet 722C printer, but I couldn't get it
to work. I asked around and everyone has answered that Linux
does not support it - is it a Windows-only printer?
If so, is it possible to write a driver for it? or does anyone know
of where I can get my hands on the driver (if it's already been
written, of course).
In an effort to reduce the production cost of their low-end printers,
HP has removed as much of the electronics from the printer as possible,
and put the burden of turning commands into dots on the printer driver
in the computer. Somewhat euphuistically, this is called the Printing
Performance Architecture, a kind of less-is-more concept which I'm
sure is big in the HP marketing Dept.
All is not lost however. There's a guy who reverse-engineered the
protocol, and has written a driver. You can find his page here:
http://www.rpi.edu/~normat/technical/ppa/
(I have not tried it, nor have I corresponded with him).
I hope this helps you.
Mitch.
(I don't work for HP. Well Ok, I do, but further away from the
bit that makes printers than you'd ever believe. I speak as an
outsider)
RE: finite elements programs for Linux
Date: Fri, 22 May 1998 09:39:29 -0700
From: "James Gilb (p27451)",
p27451@email.sps.mot.com
To: berntsen@bkm.dtu.dk
At the department where I am sitting they are planning to buy a PC-bar, and they intend to put NT on the machines.
I would benefit from them putting Linux on them, since I could then use
them for simulations overnight. ...
I don't know anything about that, so I am looking for info; should I accept their arguments or is it
that he just does not know what can be gotten for Linux? Commercial Finite Element Method (FEM) programs are
also in the searchlight!
There a some really neat FEM codes out there that are free or
semi-free. Check out the Scientific Applications for Linux (SAL) page,
sponsored by Kachina Tech at
http:// SAL.KachinaTech.COM/
Next, go to the INTERNET FINITE ELEMENT RESOURCES page at:
http://www.engr.usask.ca/~macphed/finite/fe_resources/
and check out the section on Public Domain FE Programs (I think FElt is
way cool). Also, there may be some commercial vendors that support
Linux as well, you should probably ask your vendors. I found Northwest
Numerics and Modeling on the above page which sells a product called
Zebulon on Linux. Also, some related software is also available on
Linux, e.g. PV-WAVE (graphics), MATLAB, Mathematica, Maple.
Finally, do a search of Linux and FEM software on your favorite search
engine. (linux + FEM + software gave me 1085 hits on www.hotbot.com).
As a postscript, the future of FEM doesn't depend on the OS it is used
on. The real work is done in numerical code that never touches the OS,
indeed an OS call in the middle of the deepest loops would cause a
severe slowdown of the program. Some of the interfaces that you use for
input, pre-processing and post-processing may be moving to NT, but there
are still substantial packages available on the big iron. In any event,
the current IA32 line from Intel is not a leader in double-precision
floating point work, the current crop of workstations will blow it away
in most floating point benchmarks. This is improving with the emphasis
on multi-media, but the new chips will be very expensive within the near
term (USD $2000-$4000 until at least 2000).
If you have any more questions, please email me.
James Gilb, p27451@email.mot.com
RE: How to enable swapping
Date: Thu, 21 May 1998 15:49:17 -0700
From: "James Gilb (p27451)",
p27451@email.sps.mot.com
To: kng@HK.Super.NET, gazette@ssc.com
My machine, which is a Pentium Pro with 64MB memory, reports no swap
space being
used. In procinfo, it always
report 0K swap space.
I did a fdisk on /dev/hda and verified that a 64MB partition of type
Linux swap (83)
is actually there.
So why is the swap never being used ?
First, make sure the partition has been turned into a swap partition by
doing an mkswap on it. Then just do swapon /dev/hda? where ? is the
partition number of the swap partition. Now, if you put an entry for the
swap partition in /etc/fstab and run swapon -a in your boot scripts
(pretty early on), then swap will be automagically enabled whenever you
boot.
James Gilb
Cuckoo Clock
Date: Sun, 24 May 1998 23:48:02 +0200
From: Jjacobsen,
jacobsen@biosys.net
My wife's grandpa has a pretty switzer-cuckoo-clock (kuckucksuhr..).
Well, I love to hear the little bird singing every hour.
That's why I wrote this little script...
#!/bin/sh
#cockoo.sh
time=`date +%I`
count=0
until [ "$count" -eq "$time" ]
do
play /usr/share/sounds/au/cuckoo.au
count=$[$count+1]
done
Then, I edited the crontab file using crontab -e:
00 * * * * /bin/cuckoo.sh
and well, it's really funny... Using my script and cron, your Linux box
will become a great switzer-kuckucks-uhr ;)
Joerg Jacobsen, Schweinfurt, Germany
Published in Linux Gazette Issue 29, June 1998
![[ TABLE OF
CONTENTS ]](../gx/indexnew.gif)
![[ FRONT PAGE ]](../gx/homenew.gif)
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!"
|
Contents:
|
News in General
June Linux Journal
The July issue of Linux
Journal will be hitting the newsstands June 5.
The focus of this issue is Science and Engineering with
articles on using Linux at CERN, the NIST Neutron Lab and the British
Antarctic Society. Also, an introduction to Samba and a look at two
programming languages: Yorick and ICON. Check out the
Table of Contents.
To subscribe to Linux Journal, click here.
Corel & Open Source
Corel and Corel Computer Corporation have announced their official
position on Linux and Open Source Software. At the Ottawa
Carleton Linux Users Group meeting, Corel announced that they will port
all of their commercial applications to Linux, including a $99 version
of Corel Word Perfect Suite 8. Corel Computer will open the source code
for the development of their NetWinder NC.
For more information:
http://www.corelcomputer.com/
http://www.corel.com/
Linus Torvalds & Richard Stallman at the USENIX Conference, June 1998
Date: Thu, 7 May 1998 10:53:17 -0700 (PDT)
Linus Torvalds, developer of Linux, and Richard Stallman, founder of the
GNU project, will participate in the USENIX Annual Technical Conference,
June 15-19, 1998, at the Marriott Hotel in New Orleans.
This year the conference includes a special track showcasing the latest
developments and interesting applications in FreeBSD, GNU, Linux, NetBSD,
OpenBSD, Samba, and more. FREENIX offers 28 talks, plus evening BoF
sessions. Share ideas and actual code with developers and avid users of
freely redistributable software.
Full program and on-line registration:
http://www.usenix.org/events/no98/
For more information:
Jackson Dodd, jackson@usenix.ORG
USENIX, the Advanced Computing Systems Association
O'Reilly's Perl Conference 2.0
Date: Fri, 22 May 1998 09:47:48 -0700 (PDT)
O'Reilly & Associates is presenting the Perl Conference
2.0 from August 17-20, 1998 at The Fairmont Hotel in San Jose,
California. Perl Conference 2.0 features two days of intensive tutorial
sessions followed by a two-day conference led by key Perl developers.
Full program and registration information is at:
http://conference.perl.com
For more information:
Ellen Elias, elias@ora.com
O'Reilly & Associates
Linux Penguins Stickers
Date: Sat, 23 May 1998 01:06:25 +0300 (EEST)
Linux Penguin Sticker Movement announces printed Linux Penguin Stickers
In cooperation with the Linux Penguin Sticker movement
http://www.jyu.fi/~juhtolv/linux-sticker/
Linux Mall has agreed to make available professionally designed and
printed Penguin Stickers for all who do not wish to print their own.
For more information:
http://www.LinuxMall.com/PP.html
Announcement and Call for Papers, 7th International Python Conference
Date: Thu, 28 May 1998 18:29:07 -0400 (EDT)
7th International Python Conference
South Shore Harbour Resort
Houston, Texas
November 10-13, 1998
For more information, visit the conference Web page at:
http://www.foretec.com/python/workshops/1998-11/
IMPORTANT DATES:
June 29: email intent to submit paper
July 27: deadline for papers and tutorials
Aug. 31: notification of acceptance for papers
Sep. 28: deadline for final versions of full papers
For more information about submitting a tutorial:
http://www.foretec.com/python/workshops/1998-11/cft.html
Jeremy Hylton, CNRI, jeremy@cnri.reston.va.us
Program Chair, 7th International Python Conference
Linux Links
Project MUSCLE:
http://www.linuxnet.com/smartcard/index.html
"Introduction to Linux" class:
http://www.learningtree.com/us/courses/330.htm#top
Linux Applications:
http://www.linuxapps.com/
Linux Advocacy:
http://www.netnomics.com/linux/
New Linux Help Page:
http://www.admin.burned.org/
Linux Links:
http://www.linuxlinks.com/
The Linux PenguinPlay Project:
http://sunsite.auc.dk/penguinplay/
ECLiPt Project:
http://eclipt.uni-klu.ac.at/
Linux Discussion Board:
http://paradigm.uor.edu/linux/wishlist/bulletinboard.html
Free Linux Support:
http://support.marko.net/
Current ports of Linux OS:
http://www.ctv.es/USERS/xose/linux/linux_ports.html
Linux Books:
http://www.technologybooks.com/linux.htm
Linux on-line bookstore:
http://www.dragonfire.net/~garym/linux.html
Project Independence: Linux for the Masses
Date: Tue, 12 May 1998 08:16:43 GMT
A system accessible only to a minority will remain a minority OS.
Project Independence believes that this is not an acceptable fate for Linux.
Project Independence aims to make Linux accessible to people with
little computing experience.
A Call For Action:
* If you want to make Linux usable
* If you favour a pragmatic approach
* If you believe in the bazaar model
* If you are unhappy when you are unable to recommend Linux to
friends and relatives,
* If you want to act upon it
Go straight to:
http://independence.dunadan.com/
For more information:
Jean Francois Martinez,
jfm2@club-internet.fr
Linux Application Development Book
Date: Tue, 12 May 1998 08:27:42 GMT
New book available from Linux Central:
Linux Application Development By Michael K. Johnson and Erik W.
Troan from Addison Wesley Publishing.
Linux Application Development helps C programmers write applications
that run on Linux.
For more information:
sales@linuxcentral.com
Software Announcements
Stalker Software Announces CommuniGate Pro Server 2.0 Beta
Date: May 15th, 1998
CommuniGate Pro 2.0 beta is the platform-independent Internet messaging server.
The new generation of the CommuniGate integrated messaging system
unifies the performance of multi-threaded operating systems, the
standards-compliance of the Internet applications, and
flexibility of the modular CommuniGate System, initially designed for MacOS.
The new version of the CommuniGate Pro is based on the Stalker Foundation
framework and can run under all major operating systems. The first released
versions can run on the Linux operating system among others.
The CommuniGate Pro server can be configured, controlled, and monitored from
any computer connected to the Internet using any Web browser application.
The administrators can monitor the Server status, create, update
and modify user accounts, delete and redirect messages in the queues,
update the communication modules settings, and configure the full-featured
CommuniGate Router.
SMTP component of the CommuniGate Pro server incorporates all the anti-
spamming features implemented in the other Stalker mail servers, including
centralized DNS-based blacklisting (RBL).
The CommuniGate Pro server is scheduled for the commercial release in
July'98.
The beta versions of the CommuniGate Pro Server are available now, free of
charge.
They can be downloaded either from the Stalker sites:
http://www.stalker.com/CommuniGatePro/
ftp://www.stalker.com//pub/CommuniGatePro/
For more information:
Ali Liptrot, ali@stalker.com,
http://www.stalker.com/
LPEvol, A Java Application
Date: Wed, 20 May 1998 14:25:25 +0200
This is a first (beta) release of LPEvol, a Java application which allows
you to
interactiveley breed LSystems objects and view the results graphically.
LSystems are (recursive) mathematical models that can be used to describe
growth patters modelling the shapes we see around us every day, like trees,
flowers and many others. LPEvol is an application which uses LParser and
PovRay to generate and draw these LSystems. You as the user then have the
choice to select the LSystems you like and then breed them (doing a
crossover,
using theGenetic Algortihm) to produce a next generation (the children )
which
will have been derived from the formulas ( genes ) describing the parents.
LPEvol requires:
- JDK 1.1.x
- lparser (default works; a modified lparser.c is shipped with LPEvol)
- PovRay 3
- cjpeg
- see the README file for other (hardware/memory) requirements.
LPEvol 0.50 is available from:
ftp://sunsite.unc.edu/pub/Linux/science/biology/
http://www.peoplesoft.com/peoplepages/g/robert_gasch/src/src.htm
For more information:
Robert Gasch, Robert_Gasch@peoplesoft.com
RED HAT LINUX 5.1
Date: May 26, 1998
Red Hat Software, Inc.
announced the June 1 release of Red Hat Linux 5.1, a powerful update
that includes enhanced installation features, as well as system
configuring, web caching, window management features and an added value
CD of applications for Linux.
For more information:
http://www.redhat.com/
Webmin version 0.51 - WWW-based configuration software
Date: Mon, 4 May 1998 07:50:19 GMT
Webmin version 0.51 is now available for download from
http://www.webmin.com/webmin/
This version allows the simple, browser-based configuration of
Unix services such as
- Apache (version 1.1, 1.2 and 1.3)
- Samba
- Crontab
- NFS exports
- BIND
- Inetd
- SYSV init scripts
- Local/remote mounts and /etc/fstab
- Users and groups
- Disk partitions
- Running processes
- Disk quotas
- Software packages
- PPP accounts
Webmin runs on Solaris 2.5 & 2.6, Redhat Linux 4 & 5, Slackware
Linux 3, Debian 1.3 and SUSE 5.1.
For more information:
Jamie Cameron, jcameron@webmin.com
banal 0.05 (bookkeeping software) released
Date: Thu, 7 May 1998 12:50:51 GMT
TITLE INFORMATION: BANAL 0.05 - or BANAL's Absolutely Not A Ledger
AUTHOR INFORMATION: Matthew Rice - Matthew.Rice@ftlsol.com
AFFILIATION INFORMATION: FTL Solutions Inc.
DATE INFORMATION: May 1998
BANAL is a bookkeeping system that allows you to track invoices,
clients, projects, TODOs, bank accounts and expenses. BANAL is a
client/server application so you can keep one set of books one your
system while allowing everyone access.
If you want to obtain BANAL and try it out, ftp to:
ftp://sunsite.unc.edu/pub/Linux/apps/financial/accounting.
and look for a file banal-X.YY.tar.gz, with
X.YY being a version number (0.00 is of course the first).
Unpack it in a "sources" directory and start reading the document
in the "doc" subdirectory.
FTL Solutions Inc. holds the copyright (I am doing it under
their time), however, it is very unrestricted (read: do what you
want but don't think of suing them). There is a more detailed
COPYRIGHT file included with the distribution.
For more information:
Matthew Rice Matthew.Rice@ftlsol.com
satlas-0.95 (solar atlas) released
Date: Mon, 4 May 1998 07:17:18 GMT
I am announcing a first public release of satlas!
Satlas is an electronic atlas of the solar sprectrum and targeted
primaraly for astronomers who do a lot of spectral analysis work.
It is based on Gtk+ and MySQL. MySQL is used to store, manage and
provide a quick access to the data, while Gtk+ is provides GUI.
http://www.physics.unc.edu/~serge/satlas/
Satlas is distributed under GNU Public License.
For more information:
Sergei Naumov, serge@astro.unc.edu
ECLiPt Mirror 2.0b1 (former SimpleMirror)
Date: Mon, 4 May 1998 07:34:37 GMT
I've just released a new version of ECLiPt-Mirror (it's original name
has been SimpleMirror). The new release includes
- - HTML-Logs, including the possibilty to directly download from this
page
- - automatic creating of index-files as an overview over all mirrors
- - download just the most recent version of some files (e.g. the linux
kernel)
- - bug fixes :-)
- - new bugs :-(
Have a look at http://eclipt.uni-klu.ac.at (and then the mirror section)
for a example usage. You can download it from the same page (under the
projects section).
For more information:
Martin Preishuber,
Martin.Preishuber@stuco.uni-klu.ac.at
Whisper 0.1 - Internet Telephone Application
Date: Thu, 7 May 1998 12:32:21 GMT
I announce the availability of Whisper -- Internet Phone.
You can use it to talk to other people on the Internet.
It uses gsm compression and should be suitable for low
speed networks (19.200 bps and up)
I uploaded the sources to /incoming/Linux on sunsite. Hopefully they
will appear in /pub/Linux/apps/sound/talk. Sources (and a binary version)
are also available at:
http://www.itp.uni-hannover.de/~roeden/whisper.html
Copying-policy: GPL
For more information:
Claus Roedenbeck,
roeden@itp.uni-hannover.de
JCam 0.3 - Java-based software for Digital Cameras
Date: Tue, 12 May 1998 08:05:54 GMT
JCam - a single software program for (almost) all OSes and
(almost) all Digital Still Cameras ...
Release 0.3 of JCam, available from http://www.jcam.com introduces
support for cameras from Fuji and Olympus ... this adds to existing
support for cameras from Epsom, Casio, Kodak ... and a neater user
interface with "LEDs" ... ;-)
For more details about supported cameras, etc, please E-Mail to
info@jcam.com or visit the Web Page at "www.jcam.com" ...
For more information:
info@jcam.com, http://www.jcam.com/
gax 1.0 - galaxy DB utility for astronomy
Date: Tue, 12 May 1998 08:14:06 GMT
Announcing the first release of Gax, a program for amateur astronomy.
Gax can create searchable databases of galaxy information that can then
be searched based on user selectable ranges for fields in the database.
The information contained in or derived from the database includes:
RA
Declination
Major/Minor Diameter
Position Angle
Magnitude
Surface Brightness
Constellation
Uranometria 2000 Map number
Local Transit Time
Report formatting is also under complete user control providing the
ability to tailor the report output to your specific needs.
Temporarily at:
http://sunsite.unc.edu/pub/Linux/Incoming/
Permanite site:
http://sunsite.unc.edu/pub/Linux/science/astronomy/
Files: 1664Kb gax-1.0.tar.gz, 1Kb gax.lsm
Copying-policy: GPL
For more information:
Mark Anderson, manders1@csc.com
SampLin, new scientific data acquisition software
Date: Tue, 12 May 1998 08:15:10 GMT
Few days ago I released first public version of scientific data
acquisition software 'SampLin' which can be found at
http://www.troja.mff.cuni.cz/~kvasnica/samplin.html.
Currently is implemented support for serial, gpib devices and
arbitrary labcards with drivers, basic-like script language and
simple plot widget. Software supports data acquisition
over TCP/IP network via RPC protocol from remote servers.
Requirements: X11R6, Qt, KDE libs, GPIB lib
*** I'M LOOKING FOR NEW PROGRAMMERS TO CONTINUE THIS PROJECT ***
For more information:
Samuel Kvasnica,
kvasnica@iaee.tuwien.ac.at
SCNN3.3 cellular neural network simulator
Date: Tue, 12 May 1998 08:33:00 GMT
The new version of our simulation system for cellular neural networks
(CNN) is now available from our home page
http://apx00.physik.uni-frankfurt.de/e_ag_rt/cnn/SCNN/
It is a zero price product, available for Intel x86 (Linux), IBM RS 6000
(AIX4), SGI Indigo (Irix 6.2), HP (HP Unix) and DEC Alpha (Ultrix). It is
planned to add versions for other Unix operating systems on request.
For more information take a look at our homepage.
For more information:
SCNN Team,
Roland Kunz,
kunz@apx12.physik.uni-frankfurt.de
Sox 12.14 - Universal Sound Processing Tool
Date: Fri, 15 May 1998 07:40:31 GMT
The latest patchlevel of Sox is now available. Sox is intended to be
the Swiss Army knife of sound processing tools. Its allows a user to
convert sounds files between any supported format including CD Audio,
.au, .voc, .wav and several others. Latest versions also include
support for playing the sound file to either Linux's /dev/dsp or a Sun
/dev/audio.
It can be downloaded from the following sites:
http://home.sprynet.com/sprynet/cbagwell/projects.html
http://sunsite.unc.edu/pub/Linux/apps/sound/convert/sox-12.14.tar.gz
For more information:
Chris Bagwell,
cbagwell@fujitsu-fnc.com
Linux Point Of Sale
Date: Mon, 18 May 1998 11:16:14 GMT
LinuxPOS Version 1.0 Released for Beta Testing
Linux Canada Inc. wishes to announce that the beta version of
LinuxPOS 1.0 is now available for evaluation. LinuxPOS is an exciting
new point of sale application written in Tcl/Tk. If you require the
power,stability and connectivity of Linux, the graphical user
interface inherent in Tck/Tk, a dynamite point of sale application and
full source code for peace of mind and/or personal customizations ---
then LinuxPOS is for you.
For more information:
Philip Tonellier, phil@linuxcanada.com,
http://www.linuxcanada.com/
SHAREWARE: QuoteGrabber-1.0 Real-time stock quotes.
Date: Tue, 26 May 1998 12:47:06 GMT
The QuoteGrabber, 1.0.0 is a universal stock market client.
A stock market tracker and portfolio manager written in Java and
developed under Linux, the QuoteGrabber provides real-time and delayed
quotes, news and charts. Fully customizable, it is a versatile tool:
- - trading: real-time quotes for www.datek.com clients and registered
users;
- - charting: intra-day, 3 month, 1 year, 2 years, 5 years;
- - news: breaking company news as they arrive;
- - portfolio management: enter all transactions, track portfolio
performance;
- - alerts: based on a combination of four criteria;
- - international stocks: US, Canada, France, UK, Germany, Italy (delayed
15-20 minutes);
The QuoteGrabber is distributed as 30-day trial shareware with a
personal license price of $25.
For more information:
Louis-David Mitterrand, mito@aparima.com,
http://www.aparima.com/quote/
Fortify now on Linux_glibc2: 128-bit Netscape crypto
Date: Tue, 26 May 1998 13:01:39 GMT
Sydney, Australia. (23 May, 1998). By popular demand, Fortify for Netscape
has now been extended to support the Linux_glibc2 editions of the
Netscape web browsers (Communicator and Navigator v4.05).
This functionality is available immediately, as part of the
Fortify-1.2.3-unix distribution. You can download this from the
Fortify web site, at http://www.fortify.net/
In a second addition to the Fortify service, the Fortify-announce
mailing list is now on-line, and open to anyone who wishes to
receive news and announcements via e-mail regarding the Fortify project.
You can subscribe to the mailing list here:
http://www.fortify.net/feedback.html
Farrell McKay, fbm@jolt.mpx.com.au
Organic molecule drawing program
Date: Tue, 26 May 1998 13:30:46 GMT
I have written a program to draw organic molecules
easily under X. You can store the picture as bitmapfile.
It is compiled with the Athena Widget Set and is also
compartible to UNIX.
You can download the sourcecode at:
http://www.uni-ulm.de/~s_tvolk/chemtool.html
copyright is GPL
For more information:
Thomas Volk, thomas.volk@student.uni-ulm.de,
http://www.uni-ulm.de/~s_tvolk/
Toshiba Linux Utilities
Date: Tue, 26 May 1998 13:43:46 GMT
The Toshiba Linux Utilities are a series of three programs that I have
written to replace Toshiba supplied MS-DOS or Microsoft Windows programs
for controlling Toshiba laptops, with Linux versions. Full details and
source code can be found at
http://www2.prestel.co.uk/hex/toshiba.html
FAN:
A update to my fan program that uses a completely new version of turning
the fan on/off. If you have tried a 1.x version of the program and it
did not work on your laptop try this version. This version is known to
work on the new Satellite Pro models (440x, 460x, 480x), and may work
on others that the previous version did not. I am particularly keen to
hear from owners of Tecra's.
SVPW:
A direct replacement for the svpw.exe program found on the Companion
diskette, for the setting/removal of supervisor passwords, and changing
whether setup can be run in user mode. Known to work on a Satellite Pro
400x, 430x, and 440x. I am keen to know if it works on other models.
To anyone reading this, svpw does not, and cannot be made to remove
passwords unless you already know the password. This is not a limitation
impossed by me. I don't know how to *crack* the passwords on Toshiba
laptops and have no interest in doing so. I will not answer any emails
relating to this.
HOTKEY:
This is not exactly a replacement for a Toshiba program, but provides
the same functionality as MaxTime(tm) does under Microsoft Windows, under
X11 when the power-up or battery save mode is changed with the Fn+F2,
Fn+F3 key combinations. Namely a small window pops up in the centre of
the screen with some icons to let you know what you are doing. It is
know to work on a Satellite Pro 400x, 430x, Portage 610x, and Tecra 740x
For more information:
Jonathan A. Buzzard, jab@hex.prestel.co.uk
GNU Midnight Commander 4.1.35 file manager
Date: Tue, 26 May 1998 14:11:12 GMT
The Midnight Commander team has just released version 4.1.35 of the
GNU Midnight Commander. For more information on the Midnight
Commander, please consult
http://www.gnome.org/mc
This program is available now in:
ftp://ftp.nuclecu.unam.mx/linux/local/mc-4.1.35.tar.gz
For more information:
Miguel de Icaza, miguel@nuclecu.unam.mx
Published in Linux Gazette Issue 29, June 1998
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!"
Contents:
Greetings from Jim Dennis
Version-a-go-go
and the Tragedy of being "Left Behind"
- Removing Lilo
from a multi-boot machine
- Question on sendmail... --or--
- 'sendmail' FEATURE
creatures for virtual domain and generic re-write tables
- Kernel
crashes
- Winmodems --or--
- More on 'WinModems': How to "lose"
Gracefully - Just say No!
- Mail on a LAN Linux
to NT --or--
- Basic e-mail Setup for
Linux?
- Remote Tape
Backups
- adduser
- Letter to Dell
- Linux on Dell Hardware
- Hello --or--
- Connecting a Dumb Terminal to your
Linux System
- Why Linux?
- Redhat telnet
- Network Cards
- A little note about
"good times" or emailed viruses --or--
- "Good Times"
are Spread to the "Great Unwashed"
- The Answer Guy --or--
- Regarding the Column's
New Look
- TACACS+ client for
Linux --or--
- TACACS and RADIUS Authentication
Models for Linux and/or PAM
- Sendmail jam --or--
- 'sendmail' Log Jams and
Capacity Problems:
running extra 'sendmail -q' processes
- PPP connection and diald --or--
- Co-ordinating diald and Manual
PPP
- getting
ppp-2.3.3 to work
- Mail access --or--
- Getting at MS-Mail from within
Linux: The Myriad Ways to Co-exist with MS Windows
- Program for
Mailer Daemons --or--
- Automated Handling for MAILER-DAEMON
Messages: Read The Sources, Luke.
Linux Gazette: The Answer Guy for June, 1998
The theme for this month seems to be "vendor support for Linux." From
the responses to my open letter to Dell, through the common problems
with "winmodems" and "winprinters" and even to the impossible dream of
running MS Windows applications and accessing Microsoft proprietary
formats from native Linux applications --- we continue to fight uphill
battles with so many vendors.
This isn't new in the broader Unix world. Readers of
A Quarter Century of Unix by Peter H. Salus should recognize
this as a as an attitude that has dominated hardware vendors for almost
thirty years. They've been prdicting the "death" of Unix (and the "death of
the Internet) almost since from the beginning.
There is some hope on the horizon. As some of you may have heard or
read Corel Computer
(the hardware division of the famous software
company) is basing it's NC (network computer) on a Strong-ARM version of
Linux. Within a week or two after that Corel Software announced their
intention of porting the rest of the applications suite to Linux (their
WordPerfect 7 and 8 have been available in Linux versions for some
time).
A little further afield it appears that
Apple Inc is starthing to make
some sense with their future OS strategy --- by "thinking different",
or "outside of the box" in a manner of speaking. Specifically they've
apparently decided to skip the planned version of Rhapsody with its
"blue" and "yellow" boxes that separated the MacOS and the
Mach/NeXTStep (Unix) personalities. Apparently buried in their
announcement for
MacOS X ("ten") is the i
rumor that your "NeXT"
(Rhapsody) native applications will co-exist on the same desktop
with yor MacOS programs --- and that the MacOS API's will be seamlessly
supported with all the multi-threaded support that the Mach microkernel
can provide. Of course you have to hear that as rumors, or read
between the lines with a considerable background in the Macintosh
architecture since it is not apparent from their own press releases,
or from the San Jose Mercury News articles on the subject. The
San Francisco Examiner sings a similarly hollow tune.
However, I'm not alone in my opinion as we see in
David K. Every's article.
I suspect he knows way more than I do on the subject.
Oddly the MacOS Rumors web site
seems to have no mention MacOS X on their site.
What does this have to do with Linux? Well, I can only continue to
speculate that mkLinux
binaries will eventually run under MacOS X (Rhapsody). I can also still hope
that, with the progress in the G3's, and the plans for the G4
generations of the PowerPC platform, and hopefully the continued
availability development of the DEC (Compaq) Alpha processor, we'll see
some real choices and competition in the market place. Linux is the
one OS that crosses all of these (and Sun
SPARC's and
SGI MIPS and others).
Some form of Unix is available on just about every platform, whether or not
it supports Linux.
As we look beyond the world of PC clones we see that there is some
vendor support. There is some hope that Microsoft's legacy will be
the separation of hardware vendors from their "control" hegemony.
Before Microsoft it was the norm for computer manufacturers to almost
completely control the availability of software for their platforms
--- Unix has undermined that control for over two decades. The popular
backlash from Microsoft's own unique form of control --- over the
collective Wintel platform --- may finally completely sever the
puppet's strings. The trickles of vendor support that you're seeing now
is largely a survival strategy. So not only will these vendors give up
the efforts to control their customer's range of software choices,
they'll be glad they did it, considering the alternative.
Jim Dennis
Copyright © 1998, James T. Dennis
Published in Linux Gazette Issue 29 June 1998
"Linux Gazette...making Linux just a little more fun!"
GUI building using the Java 1.1 AWT
Java Linux Audio CD Player--Part 2
Contents:
In my previous article I described a simple CD player that can be
extended to create a GUI player such as Jcd, a freeware player I've
made available on the Web, see http://www.actrix.gen.nz/users/michael/giveaways.html
In this article I will describe how to extend the Drive object so that
it can carry out programmed play (play a list of tracks) and shuffle
play (play every track once in a random order).
The structure of the new player is described by the class diagram in
the following figure. Rather than starting
with the low level components, I thought it would be more interesting
to start with a description of the GUI interface. For the moment just
assume that there is a new SmartDrive version of Drive that includes
all the old functionality, plus monitoring of the Drive state and the
ability to accept and modify a list of tracks to be played. I'll
introduce the use of the new functionality as we proceed.
In my previous article I described a Java class, called ``Drive'', that
provides the following CD player functionality:
Drive Object:
Informational methods:
currentTrack, currentIndex, numberOfTracks,
currentAddress,
cdEndAddress, trackAddress, trackLength
Control methods:
play, stop, pause, resume, eject, setVolume
In this article I will describe how to extend the Drive object so that
it can carry out programmed play (play a list of tracks) and shuffle
play (play every track once in a random order). But rather than start
with the low level components, I thought it would be more interesting
to start with a description of the GUI interface. For the moment just
assume that there is a new SmartDrive version of Drive that includes
all the old functionality, plus monitoring of the Drive state and the
ability to accept and modify a list of tracks to be played. I'll
introduce the use of the new functionality as we proceed.
Since writing my previous article, the Java Development Kit 1.1 has
been ported to Linux. This code in this article will use features of
the AWT from JDK 1.1. The article was originally written using the
JDK 1.0.1, and the original JDK 1.0.1 code is included in the tar
available at SSC's Linux Journal ftp site.
The Player Class
The new CD player I'm going to describe is called Player and is run
from the command line by entering:
setenv SBPCD 1 # if you have an old SoundBlaster connected drive
java Jcd.Player
Running the application creates the GUI interface in Figure
1 and Figure 2.
The source code for the Player class is presented in
Listing 1.
The
Player class has a static main() method on line 30, which is where
program execution will begin. On line 32 the main() method creates an
instance of the player class:
Player player = new Player();
On lines 38 to 43, the Player's class constructor sets up the
SmartDrive object that communicates with the CD player. The name of
the device to open (/dev/cdrom) and the location of the native module
(Jcd_Drive.so) is hard coded into the Player's constructor. The native
module implements the kernel interface to the CDROM drive. In a real
production version of the system, these parameters would be read from
a configuration file or deduced by interrogating the operating
environment.
As previously stated SmartDrive is an extended version of the hardware
interface class described in my first article--it has been enhanced
to support programmed play, and to provide notification events
concerning the CD players status. On line 56, the Player's
constructor starts the SmartDrive's monitor. The monitor will begin
delivering CD player events to any object that has registered for them.
Figure 1. GUI Components
I'll now go back over Player and look at some of the code involved in
the GUI. On lines 45 to 54 of
Listing 1.
the Player's constructor
creates the GUI components seen in Figure 1: a menu-bar; a display
area for track info; and a control area of push-button CD player
controls.
The Form Panel
The AWT GUI toolkit provides components such as text-labels,
text-entry fields, menus, and buttons. Components are placed into
containers to build windows and pabels. The AWT's top level component
container is the Frame class. A Frame constructs a separate
free-standing window. Like other GUI toolkits, the AWT provides the
programmer with sub-container classes that can be used to control
component placement by subdividing a window into smaller areas. The
AWT's major sub-container is the Panel class. The AWT provides
further control over placement by allowing the programmer to configure
a Frame or Panel's layout policy. For example, the standard AWT
FlowLayout just places components left to right, top to bottom. A
Frame or Panel's layout can be assigned from the layouts provided by
the AWT or you can write your own.
On line 10 of Listing 1, the Player class is declared to extend the
Form class. The source code for Form is presented in Listing 2. Form
is a class I've created that extends the normal top level AWT Frame
class. Player is a Form, a Form is a Frame, a Frame creates a
free-standing window, so Player creates a free-standing window. The
Form class uses the AWT GridBagLayout manager. The GridBagLayout
manager is the AWT's most flexible layout manager. It has a wide
variety of options for the spacing, and placement of objects with a
Frame or Panel. GridBagLayout's flexibility makes it complex to deal
with. Form simplifies dealing with the GridBagLayout by providing an
addCenter() method. On lines 23 to 32 of
Listing 2, the addCenter()
method controls placement by placing the object at the next available
row and making it consume the entire row:
c.gridx = 0;
...
c.gridwidth = GridBagConstraints.REMAINDER;
It sets fill to NONE. It sets the inset space around the component to
1. The end effect is that the Form sub-class will place objects top to
button, one object per row, each consuming the space it needs plus
a little surrounding space.
The Menu Bar
Returning to the Player class. On lines 46 and 47 of Listing 1,
the Player's constructor sets up the windows menu bar:
setMenuBar(new MenuBar());
getMenuBar().add(createFileMenu());
The actual drop-down menu is created by the createFileMenu() method on
Lines 70 to 78 of Listing 1.
It creates the player's file-menu, and
adds individual menu items to it. Lines 76 and 77 of createFileMenu()
setup the event handling for the menu:
fileProgramItem.addActionListener(this);
fileExitItem.addActionListener(this);
These two lines set up the Player object (this) to handle the
ActionEvents from the file-menu's fileProgramItem and fileExitItem.
These events are generated when the user selects a menu item. In
order to be able to handle these events the Player class must
implement the ActionListener interface--it is declared as such on
Listing 1 line 10:
public class Player extends Form implements ActionListener
What's going on here? Player inherits from--``extends''--Form, but
what does ``implements ActionLister'' mean? Player can only inherit
data and method definitions from a single parent--Java doesn't
support multiple inheritance--an object can only ``extend'' one parent
class. However, to provide some of the functionality of multiple
inheritance, Java provides the ``implements/interface'' mechanism. In
other languages multiple inheritance has to deal with the issue of
what to do when a class inherits two more implementations of the same
data-structure or method from two different parents. For example, say
both parents have an add() method, which one should be used in the
sub-class? Java's limited multiple inheritance mechanism, the
``interface'', doesn't support the inheritance of implementation.
Except for class-wide constants, interface definitions must be
completely abstract. An interface definition, such as ActionListener,
cannot provide an implementation of any of the methods it declares.
Any class wishing to ``implement'' an interface must provide its own
code to implement all the methods in the interface. A class can
implement any number of interfaces--a class could implement both
ActionListener and MouseListener and handle both kinds of events. By
not providing an implementation, interfaces leave conflict resolution
in the hands of the programmer designing the implementation.
Listener interfaces such as ActionListener, MouseListener, and others,
were newly introduced in JDK 1.1. The new JDK 1.1 AWT Event model
uses the Java interface mechanism to provide a more flexible event
handling mechanism that the earlier version of the JDK. There are
separate interfaces for different kinds of events such as the mouse or
the keyboard. Multiple objects can register for the same events and
they will all receive them.
In order to implement the ActionListener interface, the Player class
has to have an actionPerformed() method--the method is defined on on
Lines 59 to 68. The Player will be passed menu events via a call to
the actionPerformed() method. The actionPerformed() method checks
which component was the source of the event and invokes an appropriate
code fragment: at lines 62 to 65, the Player's actionPerformed method
checks if the source of the event was the fileProgramItem--if it was,
and there isn't an existing program showing, a new one is created. At
line 66, if the source of the event was fileExitItem the program is
terminated.
AWT Adapters
In some cases the interface necessary to handle an AWT event is quite
complex. To save the programmer the work of having to completely
define all of an AWT event interface, the AWT includes pre-written
Adapter classes that provide default implementations for the more
complex event interfaces. For example the MouseListener interface has
a corresponding MouseAdapter class that provides a default
implementation. These pre-canned AWT Adapter classes can be
sub-classed to selectively override any of their methods.
The Player class makes use of an Adapter class to handle close
requests from the window manager. Close requests are usually the
result of the user double clicking the close button on window's title
bar. On line 52 of Listing 1, the Player registers a WindowListener:
addWindowListener(new DoClose());
The WindowListener interface has several methods and I only want to
override one of them--the windowClosing() method. Unfortunately the
Player class can't inherit from the default WindowAdaptor class
because the Player class already inherits from the Form class. The
solution I've applied in this case is to use another new feature of
the JDK 1.1. JDK 1.1 adds Inner Classes to the Java language--this
means I can declare a class within a class:
public class Player extends Form implements ActionListener {
...
addWindowListener(new DoClose());
...
private class DoClose extends WindowAdapter {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
}
...
}
The Player uses addWindowListener() to register a new instance of its
own inner DoClose class. Because DoClose is an Inner Class of
Player it has access to Player's data and methods and can therefore be
more closely integrated into Player than a separately declared class.
In other languages it's quite common to solve situations such as this
by passing pointers to methods, functions, or code-fragments--but in
Java only objects can be passed, so Inner Classes were provided as one
solution.
The Main Button Controls
Turning now to the remainder of the Player GUI interface: the Controls
and Display classes. I'll describe the Controls class first because
it's the simplest. Controls is a panel of buttons which you can see
on the bottom of Figure 1. Listing 3
shows the source code for the
Controls class. Since it is intended to be a sub-panel of Player it
inherits from Panel:
class Controls extends Panel implements ActionListener
The Controls class also needs to take action when the buttons are
pressed, so it also implements the ActionLister interface.
Lines 17 to 22 of Listing 3 declares the set of buttons. The button
declarations also specify how to initialize the buttons when a
Controls object is created. On lines 26 to 32, the Controls
constructor adds each of the buttons to the Panel. The simple
GridLayout manager, not to be confused with the more complex
GridBagLayout manager, is used to control component placement within
the Panel. GridLayout places components left to right, top to bottom,
in equal sized cells in the grid specified:
setLayout(new GridLayout(1, 6, 2, 2));
In this case the grid is 1 row by 6 columns--a column for each
button. The last two arguments specify a horizontal and vertical gap
between grid cells of 2.
The Controls add() method, on lines 31 to 34, overrides the add()
method inherited from the Panel super-class. Add() behavour has been
modified to set the Controls object as the ActionListener for each
button:
private void add(Button b) {
b.addActionListener(this);
super.add(b); // Now call super class add() method.
}
The Controls actionPerformed() method, lines 36 to 49, reponds to
button press events by invoking corresponding CdPlayer methods.
The CD Player Status Display
The final part of the interface shown in Figure 1
is the Display
panel, the source code for which can be seen in Listing 4. The
Display panel consists of three text fields to display the CD track,
the CD index, and the CD track time remaining--trackField,
indexField, and timeField. They're declared on lines 13 to 15 of
Listing 4 and will be initialized as new TextFields a Display object
is created (which only ever happens once in this application).
The Display() constructor method is on line 20 of Listing 4. Lines 22
to 29 setup the basic components involved in the display. The Panel
is assigned the FlowLayout manager which means that calls to the add()
method will place the three text fields in a left to right layout
butted up to each other with a small amount of separation top and
bottom. And on Lines 23 and 24 I've made the indexField and timeField
read-only so the user can't alter their values:
indexField.setEditable(false);
timeField.setEditable(false);
The trackField is left editable so that the user can enter the number
of a track to start playing from. In order to handle the trackField's
mouse focus events and keyboard events, we have to register a couple
of event Listeners:
trackField.addFocusListener(new TrackFocusLost());
trackField.addKeyListener(new TrackKeyPress());
Both of the Listeners are quite complex, so rather that write our own
complete implementations, two default Adapter classes are sub-classed
to handle the task on lines 53 to 74--more about them later.
On line 34 we register Display() as an Observer of the cdPlayer:
cdPlayer.monitor.addObserver(this);
The status of the CD player is actually kept track of by a Monitor
object--the cdPlayer.monitor object. The monitor runs in its own
thread (a thread can be thought of as a light weight sub-process that
has shared access to the data of the main task). The need to monitor
events and notify other objects is a common programming problem. Java
provides the Observable Class, and its companion Observer Interface,
as a standard basis for addressing this kind of problem. The monitor
object is a sub-class of a Observable class. The Observable class
provides the code necessary to manage the Observer/Observable
relationship. The monitor class will be described in more detail
later. Display is declared to implement Observer, which means it must
define an update() method. The update() method will be called when an
Observable event takes place. Display's update() method is defined on
lines 37 to 51, it is passed the Observable object that caused the
event and an extra argument (which isn't used in this application).
Normally the trackField is updated once a second when the monitor
broadcasts a status update to its Observers. The user can also alter
the value of the trackField by entering a new track which will force
the player to skip to it immediately. To prevent the one second
update from clobbering the users input, the update() method is careful
not to update the trackField text unless the track really has changed:
if (prevText.compareTo(newTrackText) != 0) {
trackField.setText(newTrackText);
prevText = newTrackText;
}
Lines 53 to 75 of Listing 4 define two inner classes to handle user
input into the trackField. TrackFocusLost restores the correct track
number when ever the user changes focus out of the trackField.
The inner class TrackKeyPress checks every key pressed in the
trackField for the enter key. If enter is pressed, an attempt is made
to parse the text entered into an integer value, if this succeeds the
cdPlayer is instructed to immediately start playing at this track.
The SmartDrive and the Monitor Thread
Before we go on to describe how to write a GUI for programmed track
play and shuffle play, we really have to understand more of the new
SmartDrive class that extends the Drive class from my first article.
SmartDrive.java can be seen in Listing
5. SmartDrive is a sub-class
of the original Drive class. SmartDrive mainly adds new methods to
provide for playing a list of tracks.
In order to store the playlist of tracks, a new class called TrackList
is defined at lines 175 to 243. TrackList is a sub-class of the JDK
Vector class. A Vector is is a JDK implementation of a list-like
structure. A Vector can only store java Objects. I would like to
store int-type track numbers, but the int-type isn't a Java Object,
it's a primitive data-type and primitive data types aren't first-class
objects. To get around this problem the JDK provides a class wrapper
for each kind of primitive data type. In this case I have to use the
Integer wrapper class to contain each track number. When ever a track
is added to a TrackList, the code actually stores a corresponding
Integer object:
addTrack(int t) { addElement(new Integer(t)); }
TrackList provides methods to test the state of the list, to advance
along the list, and to reset the list. Because Vectors store generic
Objects, TrackList also has to do a fair bit of casting. For example,
elementAt() returns an Object that has to be cast to an Integer before
I can use it:
Integer elem = (Integer) (elementAt(position)); // Cast Object to Integer
The methods within TrackList have been declared as synchronized.
This prevents multiple threads from simultaneously trying to access
the same TrackList object. For example, we don't want the GUI to
attempt to clear the track list at the same time as the cdPlayer
attempts to advance to the next track in the track list. By declaring
the methods as synchronized we ensures that requests are handled one
at a time--waiting calls will block until the object is available.
In order to implement programmed play, the SmartDrive class includes
an instance of TrackList, called tracksToPlay. SmartDrive methods
such as next() and prev(), on lines 53 to 83, either just play tracks
in the normal numerical sequence, or in the order returned by
the tracksToPlay nextTrack(), prevTrack() methods.
Anytime the player gets to the end of track SmartDrive has to refer to
tracksToPlay and issue a new play() call to play the next track in the
program. In order to do this it sets up an instanse of the Monitor object
mentioned earlier.
2b:The code for the Monitor class is in Listing 6. As described earlier
the monitor object is a sub-class of a Observable class, a JDK class
that provides much of the code necessary to manage Observer/Observable
relationship. The Monitor class runs in a separate thread that
interrogates the hardware player and passes on its status every second.
The monitor is started by calling the monitor's start() method--in
this case the call to start() is made in the main() method in
Listing 1. The Monitor's start()
method, lines 57 to 65 of Listing 6,
creates a new thread and starts it running:
if (updateThread == null) {
System.out.println("Starting thread");
updateThread = new Thread(this);
updateThread.start();
}
The Thread constructor expects to be passed an object that implements
the Runnable interface, in this case the Monitor is its own Runnable,
so it passes itself (``this''). To implement the Runnable interface,
Monitor has to define a run() method. The run() method provides the
code that will be executed in a new thread. When the
updateThread.start() method is called the new execution thread will be
created. The new thread will then call the the monitor's, run()
method. The run() method loops forever collecting status from the
cdPlayer, passing it on, and then sleeping one second. The update is
carried out in a synchronized statement:
synchronized (cdPlayer) {
updateCdInfo();
setChanged(); // Force notifyObservers() to do its thing.
notifyObservers();
}
The synchronized statement will obtain a lock on the cdPlayer before
it updates its info and notifies each observer. This ensures that all
Observers get the same consistent picture. The monitor uses the
setChanged() method, inherited from Observable, to indicate that the
Observers need to be informed. It then calls the notifyObservers()
method, also inherited from Observers, which passes the update event
on to all Observers who have previous registered with the monitor.
The bulk of the Monitor class on lines 72 to 127 implements the
updateCDInfo() method that collects info from the Drive/SmartDrive
object. It caches the CD info to save having to bother the Linux
kernel with repeated requests for constant information such as the
length of the tracks on the current CD. The Drive interface was
extensively covered in my first article, so won't go into the
the details of the calls to the cdPlayer again here.
Although the monitor provides the main means for conveying status
information, the SmartDrives's update() method, lines 118 to 148 of
Listing 5, has to switch into more precise mode to handle the
transition from one track to the next. The normal one second update
from the monitor is insufficient to control precise switching between
tracks so the update() method does it's own frequent polling when ever
the end of track is near:
if (monitor.currentAddress >= tend - 210) { // Near end of
track?
// Poll frequently so we don't miss the event.
while (currentAddress()
&& monitor.status == Drive.STATUS_PLAY
&& currentAddress() != 0) {
try { Thread.sleep(100); } // Sleep 100 msec's.
catch (InterruptedException e) { }
}
This ensures that the listener doesn't hear small sound bites of the
next track.
The Program Window
Figure 2. Program Window
Now we can address the final GUI component--the Program class that
creates the Program window. The Program window can be seen in
Figure 2. The source code for the program class can be seen in
Listing 7.
The Program class lays out its sub-panels by using the same
Form object described earlier. The Program constructor, lines 40 to
87, assembles three sub-panels:
+ programListing - a text field;
+ trackPanel - a grid of track buttons;
+ and buttonPanel - a row of control buttons.
The program class isn't really any more complex than the rest of the
GUI except that it features quite extensive use of Inner Classes and
Anonymous Classes newly introduced in Java 1.1. Most of the following
description will concentrate on these two new language features.
Lines 53 to 70 setup the buttonPanel and the actions to take when each
control button is pressed. The Program() constructor uses the Program's
own addButton() method to add the control buttons to the buttonPanel.
AddButton() expects to passed the panel; the button; and an object to
handle the associated button press action:
void addButton(Panel panel, Button button, DoAction action)
{
panel.add(button);
button.addActionListener(action);
}
The action parameter, is declared to be from the DoAction class.
DoAction is declared at the top of the Program class as an Inner
class--a class contained within the Program class:
class Program extends Form implements Observer {
private abstract class DoAction implements ActionListener {
public void actionPerformed(ActionEvent event) {
this.invoke();
}
abstract void invoke();
}
The DoAction class is abstract because it has no implementation for the
invoke() method. The implementation of invoke() is provided
individually for each button by new sub-classes of DoAction.
These new sub-classes are created inside the Program() constructor on lines
54 to 78--each addButton() call creates a new DoAction sub-class:
addButton(buttonPanel,
editButton,
new DoAction() { void invoke() { setEditMode(); } });
In each of these calls to addButton, the last paramter is an Anonymous
sub-class of DoAction. Like Inner Classes, Anonymous Classes were
added to Java to give programmers the means for implementing objects
like ActionListeners without the programmer having to creating
zillions of free standing mini classes. The new verb, normally used
to create a new object, is used here to create a new class:
new DoAction() { void invoke() { setEditMode(); } }
This code creates a new anonymous, i.e., unnamed, sub-class of DoAction.
The body of the class, in the curly-braces, provides an implementation
of the invoke() method specific to the editButton. In the same manner
6 other anonymous classes are created to handle each control button.
Another anonymous class is used to handle the close-request for the
Program window on lines 71 to 79. Rather than fully declare a single
class to handle the request, I've used an anonymous sub-class of the
AWT WindowAdapter class:
new WindowAdapter() {
public void windowClosing(WindowEvent e) {
dismiss(); // call dismiss(0) for the outer class.
}
}
Again ``new'' is creating a new class. In this case a sub-class of
WindoAdapter is created with an override for the windowClosing()
method.
Because these anonymous classes are inner classes of Program, they
have access to its data and methods. For example, windowClosing() in
the previous example calls dismiss()--dismiss() is a method of the
Program class.
The suggested use for Anonymous classes is for small fragments of
code only. Larger code fragments are more tidily expressed as
named inner classes.
The updateTrackPanel() method, on lines 171 to 194, contains a tricky
use of inner classes. Here inner classes are used to carry extra
information around. When the Program window is created the
updateTrackPanel() method is called to set up the track-number
buttons. The method is also called whenever the number of buttons has
to be altered due to a change in CD.
When the user presses a track-number button, the button event handler
has to know which button was pressed. updateTrackPanel() achieves
this by sub-classing the DoAction class:
for (int i = prev_n; i
class TrackAction extends DoAction {
int track;
public TrackAction(int i) { track = i; }
void invoke() { pickTrack(track); }
}
addButton(trackPanel,
new Button(Integer.toString(i + 1)),
new TrackAction(i + 1));
}
Each TrackAction objects is initialised with the track number it is
associated with.
The rest of the code in the Program class deals with the mechanics of
programmed mode play. This includes switching the mode of the track
panel between add (a track), del (a track), and play (immediately play
a track). The new java feature introduced by this code is the use of
the JDK Random class to select tracks at random on lines 152 to 169.
Summary
This concludes my description of how the CD player works. I started
this whole exercise to try out as much Java as possible, both in terms
of the compilers and tools, and in terms of the language and JDK
libraries. I've found that the langauge, libraries, and compilers are
stable enough to for me to write non trivial programs, the fully coded
Jcd clocks in at 3600 lines of Java and 450 lines of C. The compilers
work but are slow. The JDK libraries are quite functional and offer
far more standard facilities than originally provided with C or C++.
C integration is easily accomplished. Programming in a garbage
collected environment is a real boost to productivity. Xemacs provided
me with a really good Java editing environment.
Resources
See previous article in Linux Gazette issue 28 for detailed references.
Tar file containing all
listings in this article
My home page
containing more infomation on Jcd.
Jcd is
available on Sunsite.
The Linux Java page--a good starting point.
Copyright © 1998, Michael Hamilton
Published in Issue 29 of Linux Gazette, June 1998
"Linux Gazette...making Linux just a little more fun!"
EMACSulation
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.
Emacs as a server
Many people meet Emacs as the default program launched by Elm to edit
an email message. Starting up Emacs in this way is a bit of a pain,
because of the delay and memory use, but also because the fresh Emacs
doesn't share buffers and a kill ring (storage for cut/copied text)
with other invocations. Rather than starting up a new Emacs for each
letter, you can set the environment variable EDITOR to
emacsclient.
The Emacs server mechanism allows one Emacs process to service editing
requests from other applications. To enable it you need to add a line
like (server-start) in ~/.emacs. When you say
emacsclient filename, the program searches for an Emacs
process (launching one if necessary) and sends it a message asking it
to edit filename. The caller process (the shell for example)
is blocked while the file is being edited. When you're finished type
C-x # and the client will be unblocked.
Gnuserv
Gnuserv is a more sophisticated remote invocation mechanism for Emacs,
written by Andy
Norman (also the author of ange-ftp).
It allows arbitrary Emacs Lisp commands to be sent to an Emacs process
running either on the local machine or on another machine on the
network.
- If you're using XEmacs everything is already set up; you will only
need to add a (gnuserv-start) to your ~/.emacs.
- Obtain the gnuserv-2.1alpha RPM from Red Hat contrib, or
the .deb for Debian Hamm and skip to 6 ;
- Download the source ;
- Edit config.h (I suggest using #define
DONT_USE_LITOUT) and gnuserv.h, where you choose the
communication method (the default is Internet domain sockets, which is necessary
if you want to be able to do the remote stuff) ;
- Put the file gnuserv.el somewhere in Emacs' load path. Let's
assume you have an ~/elisp/ directory where you put your
favorite Emacs Lisp extensions; an alternative is to copy gnuserv.el
to a site-wide Emacs Lisp directory such as
/usr/lib/emacs/site-lisp (type C-h v load-path in
Emacs to see a list of possiblities) ;
- Add something like this to your ~/.emacs :
(setq load-path (cons (expand-file-name "~/elisp") load-path))
(autoload 'gnuserv-start "gnuserv" "Better Emacs server support")
(setq gnuserv-frame (current-frame))
(gnuserv-start)
The second line tells Emacs that the function gnuserv-start is
defined in a file called gnuserv.el, which Emacs will load on demand.
The third line inhibits the default behaviour of opeing a new frame for
each new file edited (leave this out if you prefer). The last line
fires up the server.
To check that everything is working, type
~$ gnuclient <filename>
which asks Emacs to open <filename>, just like
emacsclient. If this doesn't work (with a message like ``Refused
connection'' or ``Broken pipe''), skip down to the Security section. You can also send off an
arbitrary bit of Emacs Lisp :
~$ gnudoit '(message "Hi there, %s!" (user-full-name))'
Applications
Now you can do all sorts of silly things. You could get two Emacsen on
networked machines to play ping pong, echoing messages back and forth.
You could use Emacs as a CGI script server, profiting from its powerful
library without incurring the overhead of launching an interpreter for
each script (a little like the FastCGI mechanism). For example,
let's hack together an external interface to Emacs' builtin
psychologist :
(defun eliza-start ()
"Fire up the doctor."
(interactive)
(doctor)
;; We only have to type return once under this interface.
(re-search-backward " twice" nil t)
(replace-match "")
(goto-char (point-max))
(buffer-substring (point-min) (point-max)))
(defun eliza-continue (str)
"Send a string to the doctor and return her response."
(interactive)
(switch-to-buffer "*doctor*")
(insert "\n" str "\n")
(doctor-read-print)
(save-excursion
(re-search-backward "\n\n\\(\\(.+\n?\\)+\\)\n\n")
(match-string 1)))
(defun eliza-cleanup ()
"Pay the bill and leave."
(interactive)
(let ((buf (get-buffer "*doctor*")))
(if buf (kill-buffer buf))))
This can be used from the command line (for CGI use you'd have to
think about the trickier question of concurrent accesses) with a script
such as
#! /bin/sh
gnudoit '(eliza-start)'
while read line
do
gnudoit "(eliza-continue \"$line\")"
done
gnudoit '(eliza-cleanup)'
You might even find constructive uses for the gnuserv technology, like
starting Gnus (an Emacs news/email
client) and ange-ftp transfers from a ``network Emacs'', so that your
primary Emacs isn't affected by networking delays. You could also
communicate with Emacs from a crontab, telling it to fetch some web
pages with Emacs/w3, or send someone an email. You could use
Netscape's third party
email/news API to invoke Emacs instead of the builtin mail and news
clients. It might also be useful for sending commands to Emacs from a
window manager menu.
Security considerations
More and more Linux distributions use good X security
as set up out of the box. You will notice for example that when you su
to root on a modern system, you will no longer be able to launch X
clients, because the X server is protected by an xauth cookie.
While allowing access to your X display is bad enough (someone could
capture all your keystrokes, for example), giving remote access to your
Emacs process is much more worrying, since Emacs can execute arbitrary
commands under your id, delete files, send insulting email to the
President of the United States, etc.
Since release 2.1, gnuserv is able to use MIT-MAGIC-COOKIE-1
authentication for remote requests. This protocol uses the contents of
your ~/.Xauthority file, as described in the xauth(1) man page.
Gnuserv requires a cookie for display number 999, which you can create
as follows (blade is the name of the machine) :
~$ xauth add blade:999 . `cat /etc/passwd | md5sum`
~$ xauth list
blade/unix:0 MIT-MAGIC-COOKIE-1 bc1d627babdbabe9d1f288d2b57c348f
blade:999 MIT-MAGIC-COOKIE-1 d89570b20925d401c05a79be67159cae
(`cat /etc/passwd | md5sum` is just a convenient way of
generating a cookie; on most Linux systems you will be able to use the
mcookie
command, or you can bake a cookie by hand). Now you should be able to
use gnuclient/gnudoit on the local machine. The next step is to
transfer the cookie to each remote machine from which you plan to
access Emacs, with a command such as :
~$ xauth extract - blade:999 | rsh remotehost.edu xauth merge -
If you don't run X you will have to fall back to a host-based access
control system : the environment variable GNU_SECURE is
assumed to point to a file which contains a list of machines which are
authorized to open connections to your Emacs process. Finally, if your
machine isn't networked, you've probably already skipped to the next
section.
How does it work?
Your command takes a fairly convoluted route to reach Emacs. There are
four parties involved in a transaction : the ``client'', or
program which wants a service from Emacs (Elm for example), the
gnuclient program (which runs on the requesting machine), the gnuserv
process (which runs on the machine running Emacs), and of course the
Emacs process itself. They communicate as indicated by the following
diagram :
The fragile aspect of the system is that if the gnuserv program dies
for some reason, everything grinds to a halt. An alternative
communication method which would involve fewer working parts could be
inspired from the Netscape remote invocation protocol. The gnuclient
capabilities would be added directly to Emacs, and a gnudoit request
would look something like
emacs -remote -lisp '(message "Hi")'
The new Emacs process would search for an existing Emacs process to
which it could dispatch the request, or service it directly. The
disadvantage is that each request would be slower, since an Emacs needs
to be forked each time. The image is most often in the disk cache, so
this wouldn't be catastrophically slow (it works OK with Mozilla, which
is far
bigger than Emacs).
Next time ...
I've received a fair bit of email asking how to customize various
aspects of Emacs, so I'll try to scratch the surface of this vast topic
next month, and discuss the Customize package. 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 (and some
systems which only halfway operate). However, as one of the leading
bits of free 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 29 of Linux Gazette, June 1998
"Linux Gazette...making Linux just a little more fun!"
The Importance of Adopting an In-House Linux Expert
Changes, even huge changes, are difficult to evaluate when you happen
to live close to whatever is undergoing the change, be it a child,
global politics, or the world of people who make a living with their
knowledge of information technology (IT) matters.
In our world, as the most common computer-dependent tasks get
standardized and as more and more raw computing power can be tapped
by more people, the figure of the white-clad ``computer priest'' is
about to vanish. But what is the world getting in exchange?
How is the young manager of a new company going to build its IT
infrastructure? No, he most likely won't phone IBM. Instead, he will order a bunch
of PCs, equipped with a various assortment of
Microsoft software. Other Microsoft software will follow, because
that's what everybody does.
Through a brief, fractal period, we have moved from one monopoly to
another, with the added disadvantage that people who blindly accept the new easy solution end up with
less-than-solid material. This material is much harder to
adapt to local needs. In the past, companies who could afford a high
level of informatization hire with a
handful of COBOL or RPGII programmers who could customize the software that needed
to be adapted.
Today, a manager will most probably be equipped with a
NT server, a Microsoft Office suite on Windows 95 for each desk, an
Ethernet network, and an assistance contract with some specialized
firm (who has to deal with dozens of other companies). He may organize
things so that his people have some limited sort of Internet
access. All standard, on a path that is being walked on by a huge mass
of people all around the globe.
As the path gets dug deeper and deeper, it gets harder to choose a
different one. This has to do with gravity: the deeper the path and
the steeper its sides, the harder the person, company or organization
has to want to choose a personal way to its own IT goals.
But why would a reasonable IT manager want to get out of the
mainstream? The keyword is customization.
Yes, you can program in Windows. But when it gets to having an
``intimate'' relationship with what actually happens, Windows leaves you
in the cold. You may find books, but unless you have uncommonly strong
links with the Microsoft engineering circles, you have no way to be
confident in the fact that whatever OS feature you are using won't
disappear without a trace in the next release. Which you will have to
use because everybody will be using it at a certain time. You end up
being dependent on the next brilliant idea they come up with at
Redmond, WA.
This strategy is evident. Human beings' laziness is again tapped, at
the benefit of a company that found itself at the right space-time
coordinates, and has been as un-principled as needed.
But if our young manager were to dedicate a moment of thought to how
to solve his IT problems, what are his choices?
- If he has enough resources, he can go the mainframe way. The road
is still open and fast becoming an elitist choice.
- If his connections with IBM are vital, or for a series of
(constantly diminishing) other reasons, he may go the OS/2 way.
- He may be romantic and like Macintoshes. There are concrete
rewards in these choices, although these give the impression of
diminishing, too.
- He may instead choose the proprietary UNIX way--yes, the
overpriced one.
- If he has a curious attitude, chances are that he has already met
Linux, and that he has seen Linux mentioned at an increasing rate
during the past months. Thanks to the Net, there is no scarcity of
information open to whomever decides to look around a bit.
- He may also decide to either write or pay somebody to write an
operating system from scratch. This seems somewhat improbable.
Let me know if I missed some important options. But of all the above,
the one that promises to bear more fruit is the Linux way. So, how to
give it a try? The best solution for a manager who would like his
computers do what is needed without learning the way himself, is to
engage the services of one or more Linux aficionados.
The Linux Aficionado
Linux has been growing like a big, healthy forest plant. Each branch
has been contributed by someone like us, who decided to spend a bit of
their free time to make the tree look and live better. Not ``for free'':
we humans always do things for a reward; it happens that money is not
the only (nor the best) reward. The impulse behind the Free Software
movement has been and still is to demonstrate to ourselves and to the
world that we worked well, that we brilliantly solved a problem. That
we created a handy tool, that was not there before. That is, that the
world is now a little bit nicer now than before we started developing
our ideas.
Of course, programmers need to survive, too. Here is what the Richard
Stallman has to say about the topic (excerpt from the GNU Manifesto):
``Won't programmers starve?''
I could answer that nobody is forced to be a programmer. Most of us
cannot manage to get any money for standing on the street and making
faces. But we are not, as a result, condemned to spend our lives
standing on the street making faces, and starving. We do something
else.
But that is the wrong answer because it accepts the questioner's
implicit assumption: that without ownership of software, programmers
cannot possibly be paid a cent. Supposedly it is all or nothing.
The real reason programmers will not starve is that it will still be
possible for them to get paid for programming; just not paid as much as
now.
Restricting copying is not the only basis for business in software.
It is the most common basis because it brings in the most money. If it
were prohibited, or rejected by the customer, software business would
move to other bases of organization which are now used less often.
There are always numerous ways to organize any kind of business.
Probably programming will not be as lucrative on the new basis as it
is now. But that is not an argument against the change. It is not
considered an injustice that sales clerks make the salaries that they
now do. If programmers made the same, that would not be an injustice
either. (In practice they would still make considerably more than
that.)
The above was written back in 1985, when programmers were still earning
big money; 12 years later, our market and contracting power has
diminished a lot. Gone are the days when a programmer could be the
best paid man in the company thanks to writing huge bits of database
access/data entry pieces of software that differed very little from
their brothers.
When the need arises for an application that is somehow different,
there is no other way than to call an actual programmer. Here are a
few characteristics that make a Linux aficionado an ideal choice for
such a special need:
- Passion. Something better than money as the reason for what we do.
- Love for quality. Learning from previous experience, and being
able to judge and better our work.
- Ability to solve problems. If a problem exists, we like see it
solved in the best possible way, and we generally find a way.
- Loyalty. If we are given recognition, an interesting place to
work in, interesting things to do and a reasonable wage, we may oppose
more than normal resistance to the lure of head hunters.
I may like to add a couple of counter-indications:
- Lack of particular enthusiasm for wearing ties or adopting
uniforms (or respecting poorly justified liberticide rules).
- The wish to understand what one is doing renders less than
desirable a sort of job where you must focus on a tiny fraction of the
whole thing, knowing nothing about the complete picture.
No Need for Another Windows95
There are recurring, well-financed efforts to create a new
good-for-everybody operating system on the robust structure of
Linux. These efforts are justified by the hope of snatching even a
small percentage of the huge market held by Microsoft.
A very small percentage of a very large sum may promise
reasonable earnings to those who follow this path.
Regardless of how things look like now, the omnipresent PC that
we see today has a limited time to live.
A very big slice of the PCs that are currently in use in the world are
used for standard operations: keeping one's correspondence, making
spreadsheet calculations, maintaining one's agenda, playing games and
looking around the Internet. How many PCs do you
know are being used with software that has been written especially for
them? The logical direction, one that much effort has been spent to
hamper, is that of including everything that a secretary, a
non-IT-oriented office worker or a common home user will ever need in
an idiot-proof box.
This tendency has at last emerged in the shape of network
computers. No matter which way is selected, the result of adopting an NC
is that, from the prospective of the user, there will simply be a
couple of plugs to insert into the respective sockets, and the user
will be ready to work or play. No need to reinstall Windows95 for the
nth time because the maintainer can't divine a better way to recover
from the cryptic error messages.
Along this way, comes the demise of shrink-wrap software.
If the server is the only place where a separate
operating system needs to be installed, it will be much harder for
Microsoft to maintain their stronghold on the computer market. NT has
very little advantage compared to the many UNIX options in the field. In
particular, it is not significantly easier to manage than UNIX by a
knowledgeable person. And if or when the networked world
becomes so easy to manage that a bunch of software wizards can
do the job, the next step will be NSes (Network Servers, I think I'll
patent the name...). Again, something that spells bad to a
software-only company that is programmed to EARN.
Isn't it futile to try to be the new Microsoft? As if it really
mattered much to have so much money that you will not have the
material possibility to spend it all in your lifetime.
Meet the Ideal Entrepreneur
So, what is there that is not futile? Doing something nice, that makes
the world a bit better. I said that before.
A human being has an idea. Some say they float around, and visit you
when you become receptive enough. She finds all the resources that are
needed to turn this idea into a practical product. After some time,
other people can exchange some of their own wealth to take advantage
of the idea of our entrepreneur.
Or the idea can be imported within a sufficiently fertile existing
corporation, one that will recognize the value of the idea and give
our human being enough space and resources to reach her goal.
Or the idea deals with bettering an established way of doing some
task.
What kind of enterprise can you think of, that won't benefit from the
use of IT? Most of the times, she will have to look for computer
assistance. It is to all the entrepreneurs who are
facing the problem of which way to informatize their pet project that
I would like to speak.
Linux may well be the best choice for you. But for Linux to adapt well
to your world, you will want to adopt one or more Linux
aficionados. You will want to secure the continuing services of a
person who deeply knows and appreciates the tools he works with. Who
can craft your personal solution. Who can maintain the operating
system that your solution works on abreast of the latest technical
progress.
Linux cannot be eternal. Nothing is. But it has reached a solid,
mature stage NOW. Especially, it is the ideal tool for tapping into
the networked world. Now is the time not to be lazy and to profit from
this situation. And keeping a Linux aficionado happy and well-fed now
might also imply finding yourself in a more elevated position in the
post-Microsoft world, tomorrow.
Copyright © 1998, Carlo Prelz
Published in Issue 29 of Linux Gazette, June 1998
"Linux Gazette...making Linux just a little more fun!"
Mastering Kernel Modules with Caldera
You shouldn't have to read this article. The concept of Linux kernel
modules is fairly simple. Unfortunately, information needed to compile,
install and use modules is scattered over several HOWTOs, READMEs,
and man pages. Plus, the files which need to be modified are in several
obscure directories.
I finally wrote this cookbook approach to get myself, and you, started.
Once you are up and running with modules, you can dig into the details
later. I tested this material on an X86 processor running Caldera Open
Linux 1.1, which is close to Red Hat 4.2. You mileage with other
processors and distributions may vary.
Why use modules? Modules let you compile a small, fast kernel, then
install and remove device drivers on demand. Without modules the Linux
kernel could bloat to resemble a certain commercial OS.
First, I recommend that you compile a base kernel
that includes all essential capabilities for your system without
modules. I know this sounds like we are going backwards, but you don't
want to lose the ability to boot up because you messed up your modules.
The README in usr/src/linux is your guide, but basically you execute
the command:
make mrproper; make xconfig
(or menuconfig or config) to include
all needed capabilities, then run:
make dep; make clean; make zImage
Save your kernel configuration to a file named kernelconf.base, in case you need to
recompile. The xconfig menu prompts you to save and load configuration
files. If you use menuconfig or config, the current configuration is in
the file /usr/src/linux/.config; copy that file to kernelconf.base. If you
configured too big a kernel, final compilation will fail. If this
happens, execute make bzImage instead of zImage.
Your compiled
kernel will be in the directory /usr/src/linux/arch/i386/boot.
You might have made a mistake in compiling your base kernel, so don't
throw away your old one. If you are running LILO, rename your new
kernel to zImage.base and copy it to the location of your current kernel,
usually / or /boot. Add a section to /etc/lilo.conf that lets you
select either your default or base kernel on boot up. My lilo.conf
is shown here minus some comment lines:
# general section
boot = /dev/hda3
install = /boot/boot.b
message = /boot/message
prompt
timeout = 50
# default entry
image = /bzImage
label = linux
root = /dev/hda3
read-only
# base kernel
image = /zImage.base
label = base
root = /dev/hda3
read-only
The important addition to lilo.conf is the last section
(#base kernel) which tells LILO about your new kernel.
Also, be sure lilo.conf
has prompt and timeout lines. Now execute
lilo and then reboot.
LILO will pause giving the prompt boot:. If you hit TAB, you will be
given the choices linux and base. Enter
base, and your new kernel will
boot. You may get complaining messages about bad module dependencies,
but if your base kernel is complete that shouldn't bother you. If
something goes wrong, reboot and enter linux (or just wait the
timeout interval) and your old kernel will boot. Make sure you have a
working base kernel before proceeding. With this approach you
never burn your bridges (or kernel) behind you.
If you don't use LILO, make a boot floppy for your base kernel. To do
this, insert a floppy and execute make zdisk, instead of zImage.
You are now ready to compile a kernel with modules tailored to your
system. Execute the same commands as above, but when you execute xconfig or
menuconfig pick some features to compile as modules. I suggest
you experiment first by picking nice-to-have, but not-necessary,
modules to add to zImage.base. Good choices might be printer support or
floppy support (unless you are booting from the floppy). Save your
configuration as kernelconf.mod in case you need to go back. Also,
write down which modules you are compiling. To know exactly which
modules are compiled, I suggest you move or delete your old modules (if
any). The Caldera release includes a lot of modules. They are in
/lib/modules/2.0.29. I moved my old ones into subdirectories rather
than deleting them in case I needed to back up. If you are working
with a different release of the kernel, instead of subdirectory 2.0.29
you will have a subdirectory corresponding to your release number.
After executing make zImage, run:
make modules; make modules_install
As before, move (using cd) to the directory containing zImage,
rename it zImage.mod and
move it to the directory where LILO will look for it. Put a new section at
the bottom of lilo.conf to let you boot this kernel with the label
modules. If you don't use LILO, make another zDisk.
Now, execute
depmod -aq. This creates /lib/modules/2.0.29/modules.dep, needed by
module utilities. Next, execute the following:
modprobe -c | grep -v '^path' > /etc/conf.modules
This command sets up another file needed by the module utilities.
Now reboot, choosing label modules at the boot prompt.
Next, move to the
/etc/modules/2.0.29 directory. It should contain a file with a very long name
like the following:
#1 Tue Feb 11 20:36:48 MET 1997.default
This file is read at boot time by /etc/rc.d/rc.modules. It contains a
list of the default modules loaded when the kernel boots. You
need to change both the name and the contents. Fixing the name is the hard
part. In directory /etc/modules/2.0.29 execute the commands:
FILE=i`uname -v`.default
cp "#1 Tue"* "$FILE"
This magic creates a file with the name that rc.modules will look for
on bootup. The name is based on the time when the kernel was compiled.
If you recompile the kernel, you must repeat the magic.
Edit this file to contain just the modules you want loaded at bootup.
For example, it might contain the lines
floppy
lp
which would load the floppy and printer modules, assuming you compiled
them as modules. To get your editor to accept this file, you may need to put
quotes around the name.
To load a module manually, execute
insmod 'modname'. To remove it execute
rmmod 'modname'. To tell which
modules are currently loaded, execute lsmod.
The best toy is kerneld; it automatically loads and unloads modules as
needed. Assume you have compiled the floppy driver as a module. Check
whether it is loaded by executing lsmod. If it is, remove it by
executing rmmod floppy. Then execute
kerneld.
Now execute mount /mnt/floppy
(or whatever mounts your floppy). Magically, kerneld
installs the floppy module when needed. It will also uninstall modules
which haven't been used for a while, keeping your kernel lean and mean.
You now know enough to experiment with modules without crashing your
kernel on bootup. Read the Module mini-HOWTO, the kerneld mini-HOWTO, and
the man pages for the utilities to become a real expert. Happy
moduling!
Resources
Module mini-HOWTO
kerneld mini-HOWTO
Copyright © 1998, David Nelson
Published in Issue 29 of Linux Gazette, June 1998
"Linux Gazette...making Linux just a little more fun!"
Replacing Windows NT Server with Linux
Copyright (c) 1997 Quinn P. Coldiron
qcoldiro@unlinfo.unl.edu
Table of Contents
Introduction
Section 1--Outlining Our Situation
Section 2-- Why we chose RedHat Linux
Section 3--Under the Hood
Appendix A--RedHat
5.0 Installation Guide
Appendix B--Samba
Appendix C--DOSEMU
Manual
Introduction
Network Operating Systems (NOS) have many features and capabilities
that allow the Information Systems departments of most organizations to
better server your organization and help streamline work flow. Each NOS
has different features and a excels in different areas. Traditionally,
Novell Netware has been viewed as the best file/printer server, Unix was
viewed as the premiere application and database server and recently, Windows
NT has come in as a good choice for the smaller networks as a file/printer
server or application server. The market has become very aggressive with
each of these platforms branching out into each others market area. Microsoft
has expanded NT into the midrange server market once dominated by Novell
and is trying to get into the high end market which was once filled by
Unix venders such as Sun, Hewlett Packard and Silicone Graphics.
I inherited an aging Novell Netware 3.11 server when I began my career
at the University of Nebraska Press that was on an under powered Pentium
90 and had older disk drives that were failing. I also wanted to expand
into other areas, so I knew this was going to be my first project. When
I began looking at my options to replace our aging Novell Netware server,
I of course turned first to the just released Windows NT Server 4.0. The
marketing materials, magazines and television advertisements all told me
that this was the one thing that would solve all my problems. The operating
system promised to be easier to setup and maintain than the Netware product
it was replacing and it could easily handle the 55 users on my network.
Fourteen months later, we are running Linux as our server.
Linux is a completely free reimplementation of the POSIX specification,
with SYSV and BSD extensions (which means it looks like Unix, but does
not come from the same source code base), which is available in both source
code and binary form. Its copyright is owned by Linus Torvalds <torvalds@transmeta.com>
and other contributors, and is freely redistributable under the terms of
the GNU General Public License (GPL). A copy of the GPL is included with
the Linux source; you can also get a copy from ftp://prep.ai.mit.edu/pub/gnu/COPYING.
Linux is not public domain, nor is it `shareware'. It is `free' software,
commonly called freeware, and you may give away or sell copies, but you
must include the source code or make it available in the same way as any
binaries you give or sell. If you distribute any modifications, you are
legally bound to distribute the source for those modifications. See the
GNU General Public License for details.
Linux is still free as of version 2.0, and will continue to be free.
Because of the nature of the GPL to which Linux is subject, it would be
illegal for it to be made not free. Note carefully: the `free' part involves
access to the source code rather than money; it is perfectly legal to charge
money for distributing Linux, so long as you also distribute the source
code. This is a generalization; if you want the fine points, read the GPL.
Linux runs on 386/486/Pentium machines with ISA, EISA, PCI and VLB busses.
MCA (IBM's proprietary bus) is not well-supported in 2.0.x and earlier
versions, but support has been added to the current development tree, 2.1.x.
If you are interested, see http://glycerine.itsmm.uni.edu/mca
There is a port to multiple Motorola 680x0 platforms (currently running
on some Amigas, Ataris, and VME machines), which now works quite well.
It requires a 68020 with an MMU, a 68030, 68040, or a 68060, and also requires
an FPU. Networking and X now work. See news:comp.os.linux.m68k
Linux runs well on DEC's Alpha CPU, currently supporting the "Jensen",
"NoName", "Cabriolet", "Universal Desktop Box" (better known as the Multia),
and many other platforms. For more information, see http://www.azstarnet.com/~axplinux/FAQ.html
Linux runs well on Sun SPARCs; most sun4c and sun4m machines now run
Linux, with support for sun4 and sun4u in active development. Red Hat Linux
is (as of this writing) the only Linux distribution available for SPARCs;
see http://www.redhat.com/support/docs/rhl-sparc/
Linux is being actively ported to the PowerPC architecture, including
PowerMac (Nubus and PCI), Motorola, IBM, and Be machines. See http://www.cs.nmt.edu/~linuxppc/
and http://www.linuxppc.org/
Ports to other machines, including MIPS and ARM, are under way and showing
various amounts of progress. Don't hold your breath, but if you are interested
and able to contribute, you may well find other developers who wish to
work with you.
Linux is no longer considered to be in beta testing, as version 1.0
was released on March 14, 1994. There are still bugs in the system, and
new bugs will creep up and be fixed as time goes on. Because Linux follows
the ``open development model'', all new versions will be released to the
public, whether or not they are considered ``production quality''. However,
in order to help people tell whether they are getting a stable version
or not, the following scheme has been implemented: Versions 1.x.y, where
x is an even number, are stable versions, and only bug fixes will be applied
as y is incremented. So from version 1.2.2 to 1.2.3, there were only bug
fixes, and no new features. Versions 1.x.y, where x is an odd number, are
beta-quality releases for developers only, and may be unstable and may
crash, and are having new features added to them all the time. From time
to time, as the current development kernel stabilizes, it will be frozen
as the new ``stable'' kernel, and development will continue on a new development
version of the kernel.
The current stable version is 2.0.31 (this will continue to change as
new device drivers get added and bugs fixed), and development has also
started on the experimental 2.1.x kernels. If 2.0.x is too new for you,
you may want to stick with 1.2.13 for the time being. However, the latest
releases of 2.0 have proved quite stable. Do note that in order to upgrade
from 1.2 to 2.0, you need to upgrade some utilities as well; you may wish
to upgrade to the latest version of your Linux distribution in order to
obtain those utilities. The Linux kernel source code also contains a file,
Documentation/Changes, which explains these changes and more.
Most versions of Linux, beta or not, are quite stable, and you can keep
using those if they do what you need and you don't want to be on the bleeding
edge. One site had a computer running version 0.97p1 (dating from the summer
of 1992) for over 136 days without an error or crash. (It would have been
longer if the backhoe operator hadn't mistaken a main power transformer
for a dumpster...) Others have posted uptimes in excess of a year. One
site still had a computer running Linux 0.99p15s over 600 days at last
report.
One thing to be aware of is that Linux is developed using an open and
distributed model, instead of a closed and centralized model like much
other software. This means that the current development version is always
public (with up to a week or two of delay) so that anybody can use it.
The result is that whenever a version with new functionality is released,
it almost always contains bugs, but it also results in a very rapid development
so that the bugs are found and corrected quickly, often in hours, as many
people work to fix them.
In contrast, the closed and centralized model means that there is only
one person or team working on the project, and they only release software
that they think is working well. Often this leads to long intervals between
releases, long waiting for bug fixes, and slower development. The latest
release of such software to the public is sometimes of higher quality,
but the development speed is generally much slower.
As of October 24, 1997, the current stable version of Linux is 2.0.31,
and the latest development version is 2.1.59.
I will begin this report by covering the areas that we were concerned
about and giving reasons that were chose options that we went with. I will
not get very technical in this fist section, but will cover in detail how
we implemented each part of the system and give examples of the configuration
files in section two.
Section 1
Our Situation
When I became the Information Systems Department manager for the University
of Nebraska Press I inherited a very tired and aging Novell Netware 3.1
server that was handling all the network serving duties for approximately
fifty users. This is not a large network and our needs are not out of the
ordinary, but this machine was due for replacement. Novell was on version
4.x, NT 4.0 had just come out and this machine was only a Pentium 90 with
data drives that were noisier than Nebraska's memorial stadium.
It was time to begin the search for replacements and I had the same
issues to deal with that my predecessors had, plus some new ones. The main
issue was compatibility with our order fulfillment and inventory system
called The Cat's Pajamas. This system was originally developed on the Data
General line of mini and mainframe computers using its interpreted language.
The system was ported to PC servers (mainly Novell Netware) when a company
called Subject Wills ported the interpreter to the PC platform. It has
a character based user interface, stores all its data in flat indexed text
files and is pretty fast and stable on the Novell platform. Our new requirements
were for remote access for our warehouse, and if possible, access for the
five Macs that we have, but spend as little money as possible.
I was not very interested in upgrading our current Netware license,
since at this time Novell was playing the CEO of the Month game which had
caused me to lose much of my confidence in the company. The next logical
choice was Microsoft Windows NT. I called Cats and asked if the application
would run on NT and they told me that they had a few installations and
things seemed to be running fine, but I would need a different version
of the DBC interpreter, which they uploaded for me. I proceeded to copy
the entire system and database to the NT server and logged on from my Windows
95 PC. I had to rewrite the batch file that Cats uses to start because
they were using Netware network commands, but I was able to get them changed
and get a session up.
At this point I thought this looked very good, so I ordered the production
server. The server was a dual CPU Pentium 150 with built in Adaptec 2940UW
SCSI controller and 256MB of RAM. I thought this would be perfect to act
as the CATS server, file server and printer server for 50 people, especially
since Netware was doing this on a Pentium 90 with 64 MB of RAM. I got the
server a few weeks later, installed NT 4.0 and Cats. After I got Cats installed
I had our business department and Customer Service department try running
some large and CPU intensive reports on it and things seemed to run great,
so we pushed it into service. At this same time I was setting up a RedHat
Linux 4.1 machine on a Pentium 100 with 32 MB of RAM. I had used RedHat
Linux in my previous position with great luck as a web server and StreamWorks
audio/video server so I wanted to see if it could fit in here, but I didn't
know where or how.
Life after moving Cats to NT was a nightmare. The system was crashing
two to three times a day with no reason that I could find. I was on the
phone with Microsoft and Cats constantly, but nobody could figure it out.
Microsoft had me apply Service Packs one through three and a few HotFixes,
which helped, but it still was crashing at least twice a week with the
infamous "Blue Screen of Death". After many weeks and about $1500.00 in
phone support from Microsoft, the technical support rep told me that I
should find a better software package than The Cat's Pajamas. This is was
not the solution I was looking for, since this is the package that a sizeable
percentage of presses our size nationwide are running, so I was forced
to bring the old Novell server back into production until I could figure
something out.
By this time I had upgraded the RedHat Linux machine to version 4.2,
but it still wasn't doing much, so I added two IDE 1.6 GB hard drives,
installed SAMBA and copied CATS over to this computer to play a little.
I was able to connect from my Windows 95 computer and run Cats without
any modifications to the batch file I had created for the NT server. I
had the Business manager and Customer Service manager try the reports again
and everything seemed fine, but I still had my doubts, so I just kept the
system up for myself and the IS department to test until a later date.
The Netware server was still holding on and doing its job until I got
a call one Thursday night at about 9:00 from our Customer Service manager.
He had been running the reindexing program to prepare for the month-end
closing that was to start Friday, but the server had crashed. I worked
on it until about 12:30 am and finally got it working, but the whole thing
died again Friday morning at about 6:30 and again at 7:00, so I knew we
were in trouble. The only option left was to replace the server now and
the only thing I had was the Linux server, so I restored Cats off our Windows
NT tape backup machine to the Linux server and changed the login scripts
to connect the users to this server for the Cats drives. Within one hour,
we were back in operation.
After completing the morning duties, we normally run a complete Cats
backup before we continue with closing which usually would take two hours
to complete on the Netware server. The Linux machine was able to do the
entire backup in 45 minutes, cutting a little over an hour off our closing
time. This increase in speed came from a decrease in hardware because the
Linux server was running only 32 MB in RAM and IDE hard drives where the
Netware server had 64 MB in RAM and SCSI drives. The speed increase has
been noticed in daily work also. I get almost daily remarks that the system
seems to be running faster and more reliable.
We have recently upgraded the CPU to a 200Mhz Pentium and have upgraded
the Memory to 64 MB to handle the newest plans of making this server replace
our Windows NT file/printer server, which still crashes about twice a month
for no reason, even after an additional $1,500 in tech support with Microsoft.
This single computer running RedHat Linux will replace both our Novell
Netware 3.11 server and our Windows NT 4.0 server, while decreasing total
hardware requirements. With the recent advances from the Samba team in
supporting the NT domain structure and the December 1997 release of RedHat
5.0, I expect to have a very efficient and inexpensive server for our Windows
95, Windows NT and Macintosh clients.
Section 2
Why
We Chose RedHat Linux
Linux is a very feature rich operating system. Many of its features are
not found on its commercial competitor Windows NT due to the fact that
Unix has been in constant development since it was invented in the early
1970's. Even though Linux has only been around since the early 90's, it
benefits from the rich archives of Unix applications and utilities because
of its POSIX compliance. Linux is unique in that the kernel does not use
any code from previous Unix implementations, but can still tap into the
libraries of BSD and System V distributions. I feel the strongest feature
of Linux is the Internet itself and the many technical users that are responsible
for the development of the many drivers and ports to other hardware platforms.
Many Intel platform bug fixes are release for Linux before they are release
in other ``mainstream'' operating systems mainly due to the fact the users
are also the developers.
-
· multitasking: several programs running at once.
-
· multi-user: several users on the same machine at once (and no
two-user licenses!)..
-
· multiplatform: runs on many different CPUs, not just Intel.
-
· multiprocessor: SMP support is available on the Intel and SPARC
platforms (with work currently in progress on other platforms), and Linux
is used in several loosely-coupled MP applications, including Beowulf systems
(see http://cesdis.gsfc.nasa.gov/linux-web/beowulf/beowulf.html) and the
Fujitsu AP1000+ SPARC-based supercomputer.
-
· runs in protected mode on the 386.
-
· has memory protection between processes, so that one program can't
bring the whole system down.
-
· demand loads executables: Linux only reads from disk those parts
of a program that are actually used.
-
· shared copy-on-write pages among executables. This means that
multiple process can use the same memory to run in. When one tries to write
to that memory, that page (4KB piece of memory) is copied somewhere else.
Copy-on-write has two benefits: increasing speed and decreasing memory
use.
-
· virtual memory using paging (not swapping whole processes) to
disk: to a separate partition or a file in the filesystem, or both, with
the possibility of adding more swapping areas during runtime (yes, they're
still called swapping areas). A total of 16 of these 128 MB swapping areas
can be used at once, for a theoretical total of 2 GB of usable swap space.
It is simple to increase this if necessary, by changing a few lines of
source code.
-
· a unified memory pool for user programs and disk cache, so that
all free memory can be used for caching, and the cache can be reduced when
running large programs.
-
· dynamically linked shared libraries (DLL's), and static libraries
too, of course.
-
· does core dumps for post-mortem analysis, allowing the use of
a debugger on a program not only while it is running but also after it
has crashed.
-
· mostly compatible with POSIX, System V, and BSD at the source
level.
-
· through an iBCS2-compliant emulation module, mostly compatible
with SCO, SVR3, and SVR4 at the binary level.
-
· all source code is available, including the whole kernel and all
drivers, the development tools and all user programs; also, all of it is
freely distributable. Plenty of commercial programs are being provided
for Linux without source, but everything that has been free, including
the entire base operating system, is still free.
-
· POSIX job control.
-
· pseudoterminals (pty's).
-
· 387-emulation in the kernel so that programs don't need to do
their own math emulation. Every computer running Linux appears to have
a math coprocessor. Of course, if your computer already contains an FPU,
it will be used instead of the emulation, and you can even compile your
own kernel with math emulation removed, for a small memory gain.
-
· support for many national or customized keyboards, and it is fairly
easy to add new ones dynamically.
-
· multiple virtual consoles: several independent login sessions
through the console, you switch by pressing a hot-key combination (not
dependent on video hardware). These are dynamically a located; you can
use up to 64.
-
· Supports several common filesystems, including minix, Xenix, and
all the common system V file systems, and has an advanced filesystem of
its own, which offers filesystems of up to 4 TB, and names up to 255 characters
long.
-
· transparent access to MS-DOS partitions (or OS/2 FAT partitions)
via a special filesystem: you don't need any special commands to use the
MS-DOS partition, it looks just like a normal Unix filesystem (except for
funny restrictions on filenames, permissions, and so on). MS-DOS 6 co pressed
partitions do not work at this time without a patch (dmsdosfs). VFAT (WNT,
Windows 95) support is available in Linux 2.0 ·special filesystem
called UMSDOS which allows Linux to be installed on a DOS filesystem.
-
· read-only HPFS-2 support for OS/2 2.1
-
· HFS (Macintosh) file system support is available separately as
a module.
-
· CD-ROM filesystem which reads all standard formats of CD-ROMs.
-
· TCP/IP networking, including ftp, telnet, NFS, etc.
-
· AppleTalk server
-
· Netware client and server
-
· Lan Manager (SMB) client and server
-
· Many networking protocols: the base protocols available in the
latest development kernels include TCP, IPv4, IPv6, AX.25, X.25, IPX, DDP
(AppleTalk), NetBEUI, Netrom, and others. Stable ne work protocols included
in the stable kernels currently include TCP, IPv4, IPX, DDP, and AX.25.
The system has to be available 365 days a year.
The Linux server has proven to be as reliable as any other server operating
system I have ever used, and more reliable than most. My past experience
includes managing Novell Netware, Windows NT 3.51 and 4.0 and Irix (Silicon
Graphics) servers. I must say that Novell has always been a steady performer,
but I have always felt that it was more complex than it needed to be. The
Silicon Graphics machines were always rock solid, but they should be when
you pay more than $20,000 for a single server.
My Linux server was initially setup in January 1997 as a test platform
to see if it could handle being a production server. At this time I had
installed a copy of The Cat's Pajamas, Apache, StreamWorks (audio/video
server) and Samba. Using Samba, I was able to connect the Information Systems
Department to this server so we could run Cats and test the audio/video
server. A typical day of testing the system would include reindexing and
reformatting Cats while serving multiple 100 megabyte video files and acting
as a file server. The Linux machine was able to handle all of this while
running on only 32 megabytes of RAM and using a Pentium 100 CPU.
From January 1997 to July 1997, we experienced only three shutdowns
of this server, two of which were caused by power failures in the building
and the third time was due to stupidity on the administrator's part. This
reliability was a key factor in our judgment to use Linux as our server
platform.
The installation of NT was simple, and it was easy to get the system
connected to all the printers, but it proved to be unreliable. We were
experiencing crashes every day, even after installing service packs one
and two. I then installed a hot fix to service pack two which was to fix
errors in the Macintosh services which helped. I was down to crashing just
one to two times a month. I also tried to run Cats off this system, which
was a complete disaster since we could not get more than five users at
a time in Cats, and reports would take forever to run.
The new server must be able to serve the Mac users
as well as the Windows clients.
The server must be able to allow connections from Windows and Macintosh
clients. All major server operating system allow for this, including Linux.
To server Windows clients, Linux uses a package called Samba. Samba is
server software for computers running under Unix or another Unix-like operating
systems with standard TCP/IP available. Samba, as it stands right now,
depends on Unix file structure, permissions, system calls and services.
It provides file and printer services for clients using some variants of
SMB (Server Message Block) protocol. SMB is a "native" networking protocol
used by MS-DOS based (in a very broad sense, including derivatives) clients.
They include those from IBM, ICL, Microsoft and even one particular Novell
product. In particular clients are distributed with `Windows for Workgroups',
`Windows 95', 'Windows NT', 'OS/2 Warp and others.
Some of Samba's server cousins include DEC Pathworks, Microsoft LAN
Manager/X, OS/2 Lan Manager, IBM LAN Server, Syntax Server and Windows
NT Server. Some clients such as Windows 95/Workgroups or Warp Connect can
also act as low volume servers with limited management facilities.
SMB is becoming very popular, mainly owing to these factors:
-
· Windows 95 has dial-up access to PPP servers with an included
service, and this service allows one to "browse" to public shares on the
Internet.
-
· Samba is "free" and this is a lot less expensive than Novell!
(friendlier too!)
-
· With Samba, Unix servers, well connected to a global network,
can speak in a "native" protocol of clients. It is much simpler to maintain
one more protocol on a capable server than teach new tricks to multiple
clients which were never meant to do something else.
-
· There is an established, well tested way of doing SMB over TCP/IP
described in publicly available RFC 1001 and RFC 1002 documents. This means
that SMB has a head start when it comes to Internet integration.
 |
On the Macintosh side, Netatalk provides the connectivity
services. Netatalk is a Unix implementation of the AppleTalk Protocol Suite,
originally for BSD-derived systems. It includes support for routing AppleTalk,
serving Unix and AFS file systems over AFP (AppleShare), serving Unix printers
and accessing AppleTalk printers over PAP. A number of other minor printing
and debugging utilities are also included. |
Compatibility with Existing Applications
This server would have to be compatible with The Cat's
Pajamas
When we tried to move to Windows NT, we were given a migration guideline
from The Cats Pajama's to follow. The instructions were simple and the
entire migration took little time, but performance was terrible. We needed
a system that could handle serving the system to the network and help maintain
the integrity of the Cats data files. I have been told that Unix heavily
caches file I/O activity (more so than Windows NT or Novell Netware), so
this added to my hopes that Linux would be a strong server platform for
Cats, which is a file I/O intensive application.
My hopes were verified when we formally flipped the switch on the Linux
server and turned off the Novell server. Cats ran smoothly and gracefully
scaled up to the normal daily user level without any slowdowns or misfortunes.
The Novell Netware server would normally experience periods when the system
would slow down severely, and then speed back up to normal levels after
5 to 10 minutes. During these slowdowns, Cat's would become virtually useless,
and sometimes users would be booted out of Cat's totally.
Another key area that I needed to be compatible with was the world Wide
Web. I needed to be able to get CGI programs that were already tested and
in use without having to develop them all myself. I also wanted to be able
to get help easily and cheaply on setting up the web server and fixing
it when it breaks. Linux uses Apache, the most widely used web server in
the world. I can easily get support from mailing lists , news groups and
Internet BBS's.
(http://www.netcraft.com/survey/)
After installing the Windows NT server, many users
complained about slows access times for the network drives.
My users equate network drive access speed with network quality. They were
very pleased with the speed of saving and opening files when they were
on the Novell Netware server, but expressed disappointment in the speed
of saving and opening files when we switch to the Windows NT server. One
way that I have very unscientifically measured the speed of the Linux server
was when we were using a Windows NT 4.0 machine to backup the Cats files
off the Linux machine. This operation took 45 minutes while the exact same
operation on the Novell server would take at least an hour longer. Currently
I am backing up CATS by creating a gzipped tar file directly on the Linux
server and it takes a little less than 45 minutes. Below is part of the
output from the df command that shows the drive I have Cats on. This shows
the current size of our Cats installation so you can get an idea of how
much information is backed up in 45 minutes.
Filesystem 1024-blocks Used Available Capacity Mounted on
/dev/hdc1 2417493 1584580 707923 69%
/usr/local/samba-sys
I could not afford to go through another costly installation
.
During the twelve months of running Windows NT 4.0 server, I have spent
more than $3,000 in technical support with Microsoft to remedy various
problems, including the frequent crashes and problems running Cats. The
fix for the crashes was always ``Install the latest service pack or hot
fix and call us back tomorrow.'' The fix for Cats was ``Get rid of The
Cat's Pajamas and find a better system which was more Windows compatible
to replace it.'' I wish I would have documented that support call with
Microsoft so I had the name of the tech rep.
Technical support is no the only area of expense involved with Windows
NT. The table below shows typical applications and the cost for each platform.
| Service |
Microsoft |
Cost |
Linux |
Cost |
| Operating
System |
Windows NT Server 4.0 |
$2,950.00 |
Linux RedHat 5.0 (CD) |
$49.00 |
| Web
Server |
Internet Information Server |
$0.00
|
Apache |
$0.00
|
| E-Mail |
Exchange 5.0 Enterprise |
$6,400.00
|
Sendmail,UW IMAP,POP-3 |
$0.00
|
| Telnet
server |
SLNet (4 user licensee) |
$300.00
|
Included free unlimited licensee |
$0.00
|
| FTP
server |
Included with IIS |
$0.00
|
Included |
$0.00
|
| Relational
Database |
SQL Server 6.5 |
$10,650.00
|
Just Logic SQL |
$219.00
|
| Proxy
Server |
Microsoft Proxy Server |
$995.00
|
Squid Object Cache |
$0.00
|
| Backup
Software |
Included |
$0.00
|
BRU, included |
$0.00
|
| Total
Cost |
|
$20,995.00
|
|
$268.00
|
|
|
|
|
|
| Number
of Users |
100 |
|
100 |
|
| Cost
per seat |
|
$212.95
|
|
$2.68
|
Low hardware requirements
I did not want to build the next Cray just to serve
55 users.
As at most University Press's, our operating budget is relatively small,
especially when compared to commercial business and some other campus departments.
This financial restriction did not allow me to purchase a server hardware
platform that I would have like to have for the NT server, but the system
was not low-end either.
Our Windows NT 4.0 server:
| OS |
Windows NT Server 4.0 (SP3) |
| CPU |
2 x Pentium 150 |
| RAM |
256 Megabytes |
| SCSI |
Adaptec 2940 |
|
-All data drives are SCSI |
|
-Boot drive is IDE |
| Ethernet |
NE2000 clone |
Our RedHat Linux 4.2 server:
| OS |
RedHat 4.2 |
| CPU |
Single Pentium 200 |
| RAM |
64 megabytes |
| SCSI |
DPT SmartCache IV |
|
-RAID Station 3 (RAID 5) |
|
-Boot drive is IDE |
| Ethernet |
NE2000 clone |
The RAID which is listed on the Linux server was not purchased
strictly for the Linux server, but was purchased to be placed on whatever
server we decided to put into production.
For myself and staff .
 |
Unix usually gets the standard rap of being difficult to
manage and requiring a steep learning curve. While many of the tools that
will be used to manage the system are still command line based, a growing
number are graphical and comparable to Windows in ease of use. This is
especially true with the RedHat distribution, which includes a graphical
control panel which allows the administrator to change system setting without
working through the many text files which store this information. The control
panels I use the most are the ones which setup the printers, file system,
users and packages. If you use the included RedHat Package manager to install
new applications, they are listed in the package manager, which allows
you to graphically see what applications are installed on your system and
remove them if wanted, much like the uninstall option on Microsoft Windows.
|
I don't want to start over each time a new version
comes out.
RedHat Linux provides a very simple upgrade system in its installation
set. The upgrade is actually better than the Microsoft Windows NT upgrade
path, since you do not have to uninstall the previous version first.
While it is not required that you uninstall the previous version of
Windows NT before installing the current release (4.0), it is recommended.
This can be a very intensive installation, since you would need to setup
all the user accounts again, along with reinstalling any software and automated
systems and scripts.
When I upgraded from RedHat 4.1 to 4.2, the installation when smoothly
whiteout any problems. While this was not a major revision step, RedHat
has assured me that the soon to be released version 5.0 will offer a smooth
transition from 4.2.
From the RedHat Linux manual:
| 1.5 Upgrading from a Prior Version
The installation process for Red Hat Linux 4.2 includes
the ability to upgrade from prior versions of Red Hat Linux (2.0, 2.1,
3.0.3, 4.0, and 4.1) which are based on RPM technology. Upgrading your
system installs the modular 2.0.x kernel as well as updated versions of
the packages which are installed on your machine. The upgrade process preserves
existing configuration files using a .rpmsave extension (e.g., sendmail.cf.rpmsave)
and leaves a log telling what actions it took in /tmp/upgradelog. As software
evolves, configuration file formats can change, so you should carefully
compare your original configuration files to the new files before integrating
your changes.
To upgrade a Red Hat Linux system, you must use a boot
floppy (and possibly a supplemental floppy), just as if you were performing
a full install. After selecting the medium to install from (and setting
up networking information if it's required), the installation procedure
prompts you to either Install or Upgrade; select Upgrade. This upgrade
procedure is the functional equivalent of running the upgrade script in
prior versions of Red Hat Linux.
Please note that some upgraded packages may ``depend''
on other packages which may not be installed on your system. The upgrade
procedure takes care of these dependencies, but it may need to install
additional packages in order to satisfy them. |
Remote control and administration
One of the most attractive features of Linux (or Unix in general) is the
ability to truly remotely control the server. Since Linux comes with a
telnet server built in, you can use virtually any computer, regardless
of operating system to telnet into the computer to do all administrative
tasks. To remotely administer a Windows NT server, you must purchase a
separate application to allow remote control. The most popular program
for this is PCAnywhere by Symantec. This approach can become costly because
you must purchase a copy for the server to act as the host, and a copy
for each computer that needs to remotely control the server. How many remote
computers need to control the server? This depends on each installation,
but I have found that it save me a lot of running by having the ability
to control the server from every PC on my network, and from home.
Telnet is text only, so this will be a drawback for many, but luckily
for us, Linux supports X Windows. X Windows can be used locally on the
server's console, like Windows NT, but can also be run remotely from any
computer that can run an X client. These remote terminals can by other
computers running Linux, or any other flavor of Unix and many X clients
can be downloaded or purchased for Windows, Windows NT and Macintosh computers.
Running X terminals does require more bandwidth, so I prefer just telneting
into the server.
Another nice feature is the ability to display results of various system
utilities in a web page. One of the things our Customer Service manager
likes to know is which users have which files open and locked while using
Cats. I wrote a simple Perl script to run the smbstatus program and print
the results as a web page.
The output web page:
| Snapshot of users for: Fri
Dec 5
11:41:18 CST 1997
This page shows currently logged on
users and locked files for the UNPLINUX server.
Right-click this page and select REFRESH
or RELOAD to force an update
Samba version 1.9.17p1
Service uid gid pid machine
----------------------------------------------
cdrom root root 11697 enterprise (129.93.31.35)
Thu Dec 4 16:35:23 1997
quinn root root 11697 enterprise (129.93.31.35)
Thu Dec 4 16:35:23 1997
M-DATA cbrumm cbrumm 11435 ds9 (129.93.31.14)
Thu Dec 4 16:08:16 1997
programs root root 11697 enterprise
(129.93.31.35) Thu Dec 4 16:35:23 1997
L-NE cbrumm cbrumm 11435 ds9 (129.93.31.14)
Thu Dec 4 16:08:29 1997
N-DBC cbrumm cbrumm 11435 ds9 (129.93.31.14)
Thu Dec 4 16:08:29 1997
O-WORK cbrumm cbrumm 11435 ds9 (129.93.31.14)
Thu Dec 4 16:08:29 1997
P-HIST cbrumm cbrumm 11435 ds9 (129.93.31.14)
Thu Dec 4 16:08:29 1997
<snip>
Locked files:
Pid DenyMode R/W Name
------------------------------
19818 DENY_NONE RDWR fileauth.txt
Fri Dec 5 11:41:14 1997
21212 DENY_NONE RDWR fileauth.txt
Fri Dec 5 11:40:28 1997
20590 DENY_NONE RDWR fileauth.txt
Fri Dec 5 11:38:56 1997
21384 DENY_NONE RDWR fileauth.txt
Fri Dec 5 11:06:15 1997
<snip>
19818 DENY_NONE RDWR filebac2.isi Fri
Dec 5 11:02:36 1997
20590 DENY_NONE RDWR filebac2.isi
Fri Dec 5 10:14:44 1997
19818 DENY_NONE RDWR fileauth.isi
Fri Dec 5 11:41:14 1997
21212 DENY_NONE RDWR fileauth.isi
Fri Dec 5 11:40:28 1997
Share mode memory usage (bytes):
92584(90%) free + 7728(7%) used +
2088(2%) overhead = 102400(100%) total |
The script that generates the above page:
#!/usr/bin/perl
# ******************************************************
# * *
# * Author: Quinn P. Coldiron *
# * Date: 12-1-97 *
# * Program: This program shows current
users of the *
# * Samba server. *
# * *
# ******************************************************
# Use cgi-lib CGI library for PERL.
require "/home/httpd/cgi-bin/cgi-lib.pl";
$date = `date`;
$users = `./smbstatus`;
#Get the data from the form.
&ReadParse;
print &PrintHeader;
print "<HTML>\n";
print "<HEAD>\n";
print "<TITLE>Logged In Samba Users</TITLE>\n";
print "</HEAD>\n";
print "<BODY BGCOLOR= #D4D4D4>\n";
print "<H1>Snapshot of users for:
$date</H1>\n";
print "This page shows currently logged
on users and locked files for the UNPLINUX server.<br>\n";
print "Right-click this page and select
REFRESH or RELOAD to force an update<br>\n";
print "<PRE>$users</PRE>\n";
print "</BODY>\n";
print "</HTML>\n"; |
Windows NT provides a graphical program to show a chart us system performance,
but it is recommended that you do not run it on the server that you want
to monitor, because the monitor program itself takes too much of the system
resources, and thus skews the data. Linux provides a system monitoring
tool called TOP that is character based so it can be run on the server.
Since it is character based, you can telnet into the server and run it
from anywhere, getting an accurate picture of how the server is running.
Sample output of TOP:
11:55am up 1 day, 15:02,
3 users, load average: 0.08, 0.04, 0.00
83 processes: 82 sleeping,
1 running, 0 zombie, 0 stopped
CPU states: 2.7% user,
4.2% system, 5.9% nice, 93.7% idle
Mem: 63204K av, 62336K
used, 868K free, 38384K shrd, 5536K buff
Swap: 114908K av, 368K
used, 114540K free 29496K cached
PID USER PRI NI SIZE
RSS SHARE STAT LIB %CPU %MEM TIME COMMAND
22390 root 10 0 540
540 400 R 0 2.8 0.8 0:00 top
22388 cats 3 0 848 848
516 S 0 1.5 1.3 0:00 login
22391 cats 10 0 660
660 524 S 0 0.7 1.0 0:00 bash
6058 root 1 0 3568 3568
1396 S 0 0.5 5.6 1:25 tkdesksh
22283 root 0 0 552 552
424 S 0 0.3 0.8 0:00 in.telnetd
22387 root 1 0 552 552
424 S 0 0.3 0.8 0:00 in.telnetd
21212 quinn 0 0 1084
1084 660 S 0 0.1 1.7 0:02 smbd
20921 root 1 0 588 536
356 S 0 0.1 0.8 0:08 SWserver
1 root 0 0 312 312 244
S 0 0.0 0.4 0:02 init
2 root 0 0 0 0 0 SW
0 0.0 0.0 0:01 kflushd
3 root -12 -12 0 0 0
SW< 0 0.0 0.0 0:00 kswapd
19509 root 0 0 1092
1092 652 S 0 0.0 1.7 0:18 smbd
331 root 0 0 812 812
480 S 0 0.0 1.2 0:00 login
21 root 0 0 280 280
216 S 0 0.0 0.4 0:00 kerneld
240 root 0 0 336 316
280 S 0 0.0 0.4 0:00 gpm
128 root 0 0 368 360
276 S 0 0.0 0.5 0:00 syslogd
137 root 0 0 496 488
268 S 0 0.0 0.7 0:00 klogd |
Under the Hood
Setting up the server
The actual installation of an operating system is often used as a judgement
on how good the system is. Just as with meeting people, you can never change
the first impression. I have found that setting up a RedHat Linux server
is as easy or even easier than setting up a Windows NT server. The setup
includes two floppies have everything needed to get the system to the point
that it can recognize the media (CDROM, FTP site, other server, etc.) that
the installation files are on. Windows NT supplies three floppies for this
purpose, but only supports CDROM installation. I have found that installing
RedHat Linux on a laptop can even be easier, since it can detect the PCMCIA
slots at installation time, while NT cannot. The most important factor
is to be familiar with the hardware you have installed in your machine,
including:
-
· hard drive(s): number and size; if you have more than one, it's
helpful to know which one is first, second, etc.
-
· memory: amount of RAM.
-
· CD-ROM: its interface type (IDE, SCSI, or other interface), and,
for non-IDE, non-SCSI CD-ROMs, the make and model number.
-
· SCSI adapter: make and model number.
-
· network card: make and model number.
-
· mouse: type (serial, PS/2, or bus mouse), protocol (Logitech,
Microsoft, MouseMan, etc.), and number of buttons; also, for serial mice,
the com port it is connected to.
-
· If you will be connected to a network, be sure you know your IP
address, netmask, gateway IP address, name server IP addresses, domain
name, and hostname. If you don't know these values, ask your network administrator.
-
Also, if you will be installing the X Window System, you should be familiar
with the following:
-
· your video card: make and model number or video chipset, amount
of video RAM.
-
· your monitor: make and model number, allowable range of horizontal
and vertical refresh rates.
You can install or upgrade Red Hat Linux/Intel via any of several basic
methods. Depending on the method you use, you need either one or two formatted
high-density (1.44 MB) 3.5-inch diskettes.
Installing from CD-ROM or via NFS requires only a boot diskette. Installing
from a hard drive, via FTP, from an SMB volume, or from a PCMCIA device
(including PCMCIA-based CD-ROMs) requires both a boot diskette and a supplemental
diskette. Section 2.3.1 below explains how to create boot and supplemental
diskettes.
CD-ROM
If you have a Red Hat Linux CD and a boot diskette you will need a supported
CD-ROM drive and either a 3.5 inch floppy drive or an operational installation
of MS-DOS on your machine in order to run the installation utility. If
a boot diskette did not accompany your CD, you will need access to a computer
running either Linux or MS-DOS to create a boot diskette from the CD.
NFS
If you wish to install over a network, you will need to mount the Red
Hat Linux CD-ROM on a machine that supports ISO-9660 file systems with
Rock Ridge extensions. The machine must also support NFS. Export the CD-ROM
file system via NFS. You will need to have name services configured, or
know the NFS server's IP address, and the path to the exported CD-ROM.
FTP
For an FTP install, you must have a boot disk and supplemental disk.
You will need to have a valid name server configured or the IP address
of the FTP server you will be using. You will also need the path to the
root of the Red Hat Linux directory on the FTP site.
SMB Shared Volume
If you wish to install from an SMB shared volume, you will need to mount
the Red Hat Linux CD-ROM on a Microsoft Windows NT or Windows 95 server
that supports shared volumes. You will need to have name services configured,
or know the server's IP address; you will also need the name of the shared
volume containing the Red Hat Linux CD-ROM and the account number and password
to use to access the volume.
Hard Drive
To install Red Hat Linux from a hard drive you will need the same boot
and supplemental disks used by the FTP install. You must first create a
RedHat directory at the top level of your directory tree. Everything you
will install should be placed in that directory. First copy the base subdirectory,
then copy the packages you want to install to another subdirectory called
RPMS. You can use available space on an existing DOS partition or a Linux
partition that is not required in the install procedure (for example, a
partition that would be used for data storage on the installed system).
If you are using a DOS filesystem, you may not be able to use the full
Linux filenames for the RPM packages. The installation process does not
care what the filenames look like, but it is a good idea that you keep
track of them so you will know what you are installing.
PCMCIA
If your CD-ROM, Ethernet card, or local hard disk is connected to a
PCMCIA adapter, you must install with PCMCIA support. You need a supported
PCMCIA controller and a supported PCMCIA SCSI adapter or Ethernet card.
Installing via PCMCIA requires the use of a supplemental diskette.
Please See Appendix A for The Official RedHat Installation Guide.
Samba Installation/Setup
Installing the Samba RPM is the easiest way to install, as you only need
to download the file and type rpm -I filename and it is installed.
Setting up Samba is simple, as you just edit a text file to tell it what
directories are going to be shared to the Windows clients. The text file's
name is smb.conf and is located in the /etc. directory if you installed
Samba using RPM. If you downloaded the .tar archive and installed Samba
using the default installation, you will find the smb.conf file in /usr/local/samba/lib/.
An advantage to installing Samba using RPM is that it is easier. A disadvantage
is that the versions are not as current, but they are usually more stable
and reliable. I choose to go directly to the Samba web pages and download
the most current non-beta release.
The picture on the left is the Network Neighborhood window on my NT
workstation and is currently showing everything that I have access to on
my Linux server.
If you installed Samba using RPM, it will automatically be started on
system startup, but I had to manually add it to my rc.local script to have
it start on bootup because I did not install from the RPM. I chose to install
from the tarballs available at the official Samba site, so I could always
have a current installation. To start the server manually, I just issue
these commands:
/usr/local/samba/bin/smbd -D
/usr/local/samba/bin/nmbd -D
Extensive has been accomplished that allows Samba to act more like an
NT server, including making a Linux server a Primary Domain Controller
and more features are currently being added. I have listed the steps that
I took in making my Linux server the Primary Domain Controller (PDC) for
our network.
1. Set up the server.
a. Create the smb.conf file.
b. Create the netlogon directory.
I put mine in /home.
c. Restart Samba.
2. Setup the Windows 95 clients. (We set our up for roaming profiles.)
Do not reboot until step 3!
a. Control Panel
1. Click Passwords, then Profiles and choose these settings:
a. Users can customize their settings.
b. Include desktop items.
c. Include start menu.
2. In the Control Panel, select Network.
a. Under Identification, set your WORKGROUP name.
b. Access control = USER-LEVEL.
c. Obtain the list from YOUR SERVER NAME.
d. Under Client Configuration
1. Select CLIENT FOR MICROSOFT NETWORKS.
2. Under that client's properties.
a. Log onto Windows NT domain.
b. Enter your WORKGROUP name.
c. Select LOG ON AND RESTORE CONNECTIONS.
e. Set primary network logon to CLIENT FOR MICROSOFT NETWORKS.
b. Set up the user profiles.
1. Install the Policy Editor from the Windows 95 CD.
2. Create a new profile called config.pol and save it into the NETLOGON
share on the Linux server. Make sure you add all the users on your server!
This step only has to be
done once, not on each client.
3. Using the Policy Editor, select Open registry from the File menu and
select the options you want.
4. Save it as config.pol and copy into the netlogon share on the Linux
server. Set its permissions as 755.
3. Reboot the Windows 95 computer(s) and logon.
4. Possible problems.
1. Windows95 OSR2 seems to send
the passwords as uppercase, so try changing the passwords on the Linux
server to uppercase.
2. I had problems making my Linux
server the WINS server, so you have some choices to fix this:
a. If you do have another NT server, make it the WINS server and point
all the clients to it.
b. Disable WINS on each client and edit the c:\windows\Lmhosts.sam file
and add the server and workstations to this file. Save the file as Lmhosts,
NOT Lmhosts.sam This file can be appended to from a server, but
I haven't tried doing it from Linux/Samba. The entries look like this:
xxx.xxx.xxx.xxx computername
c. Disable WINS. At this time, we are running our Win95 clients with WINS
disabled, but we do have a DNS server.
My Samba configuration (smb.conf) file looks like this:
; *******************************************************************
; *
; * Samba config file for UNPLINUX
; * Quinn P. Coldiron
; *
; *******************************************************************
[global]
workgroup = UNP
comment = Unplinux Server
volume = RedHat5
lock directory = /var/lock/samba
locking = yes
strict locking = no
share modes = yes
security = user
os level = 65
domain master = yes
local master = yes
prefered master = yes
domain logons = yes
wins support = yes
;logon script = %m.bat ; per workstation (machine)
;logon script = logon.bat
logon script = %U.bat
preserve case = yes
short case preserve = yes
case sensitive = no
; printing = BSD or SYSV or AIX, etc..
printing = bsd
printcap name = /etc/printcap
load printers = yes
print command = /usr/bin/lpr -r -P %p %s
[netlogon]
comment = Samba Network Logon Service
path = /home/netlogon
case sensitive = no
guest ok = yes
locking = no
read only = yes
browseable = yes ; say NO if you want to hide the NETLOGON share
;admin users = @wheel
create mode = 0755
; ###############################################################################
; # #
; # Printers #
; # #
; ###############################################################################
; I couldn't get the generic printers section to work, so I commented
it out
; and explicitly declared the printers.
;[printers]
; comment = All Printers
; path = /var/spool/samba-print
; browseable = yes
; printable = yes
; Set public = yes to allow user 'guest account' to print
; public = no
; writable = no
; create mode = 0700
[Technology]
comment = Technology Printer
path = /var/spool/samba-print
print = Technology
browseable = yes
printable = yes
public = yes
writeable = yes
create mode = 0777
[Marketing2]
comment = Technology Printer
path = /var/spool/samba-print
print = Marketing2
browseable = yes
printable = yes
public = yes
writeable = yes
create mode = 0777
[Marketing1]
comment = Technology Printer
path = /var/spool/samba-print
print = Marketing1
browseable = yes
printable = yes
public = yes
writeable = yes
create mode = 0777
[CustServ]
comment = Technology Printer
path = /var/spool/samba-print
print = CustServ
browseable = yes
printable = yes
public = yes
writeable = yes
create mode = 0777
[CanonColor]
comment = Color Laser Printer
path = /var/spool/samba-print
print = CanonColor
browseable = yes
printable = yes
public = yes
writeable = yes
create mode = 0777
; ###############################################################################
; # #
; # Shared Volumes #
; # #
; ###############################################################################
[homes]
comment = Home Directories
browseable = no
writable = yes
read only = no
preserve case = yes
short preserve case = yes
;create mode = 0777
[userdata]
comment = All userdata that you are allowed to see.
path = /home
writeable = yes
;Full control for your stuff, full in you group, nothing for other
;people's stuff.
create mode = 0770
[sys]
comment = System drive. Various Press utilities.
path = /usr/local/samba-sys/
writeable = yes
create mode = 0777
[programs]
comment = Program drive. Installation sets and programs.
path = /usr/local/samba-programs
writeable = yes
create mode = 0777
[ulrich]
comment = Ulrich's PLUS.
path = /usr/local/samba-programs/ulrich
create mode = 555
[cdrom]
comment = Internal IDE cdrom. For temporary usage.
path = /mnt/cdrom
[dictionary]
comment = Random House Dictionary.
path = /mnt/scd1
[bip]
comment = Bowker Books In Print CDROM
path = /mnt/scd0
[msoffice]
comment = Microsoft Office Bookshelf Reference.
path = /mnt/scd3
[encarta]
comment = Microsoft Encarta
path = /mnt/scd2
[press]
comment = Press share. Marketing maps this to U:
path = /home/press
writeable = yes
create mode = 0777
[CATS-VOL]
comment = Entire Cats volume for backup
path = /usr/local/samba-cats/
writeable = yes
printable = no
guest ok = yes
public = yes
create mask = 0777
[L-NE]
comment = Cat's root. Map as L.
path = /usr/local/samba-cats/ne
writeable = yes
printable = no
guest ok = yes
public = yes
create mask = 0777
[M-DATA]
comment = Cat's data drive. Map as M.
path = /usr/local/samba-cats/ne/data
writeable = yes
printable = no
guest ok = yes
public = yes
create mask = 0777
[N-DBC]
comment = Cat's program drive. Map as N.
path = /usr/local/samba-cats/ne/dbc
writeable = yes
printable = no
guest ok = yes
public = yes
create mask = 0777
[O-WORK]
comment = Cat's work drive. Map as O.
path = /usr/local/samba-cats/ne/work
writeable = yes
printable = no
guest ok = yes
public = yes
create mask = 0777
[P-HIST]
comment = Cat's history drive. Map as P.
path = /usr/local/samba-cats/ne/hist
writeable = yes
printable = no
guest ok = yes
public = yes
create mask = 0777
|
My actual logon.bat batch file is here:
REM *******************************************************
REM * *
REM * University of Nebraska Press network logon script. *
REM * *
REM * Last modified : 10-16-97 *
REM * By: Quinn *
REM * *
REM * The drive letter scheme is leftover from the past *
REM * network administrator and the Novell Netware 3.1 *
REM * server he had. *
REM *******************************************************
REM User's home drives
net use e: \\unplinux\homes
REM General network drives
net use f: \\intrepid\sys
net use g: \\intrepid\userdata
net use h: \\intrepid\dictionary
net use i: \\intrepid\bip
net use j: \\intrepid\programs
net use s: \\unplinux\ulrich
REM CATS drives
net use l: \\unplinux\l-ne
net use m: \\unplinux\m-data
net use n: \\unplinux\n-dbc
net use o: \\unplinux\o-work
net use p: \\unplinux\p-hist
REM Temp entry for Robotronics
REM The old system had robo on the T:\ drive but
REM all new installations will run robo from the j:\ drive.
net use t: \\unplinux\programs |
Netatalk
Installation/Setup
Netatalk offers the same installation options as Samba, so you can choose
either the RPM, or .tar archives. I would choose the RPM here, as they
are the same versions as the .tar files and make life easier during installation.
I really don't have mush to say about this installation, since it was very
simple and straight forward. After installing the package, I just edited
the AppleVolumes.system file and started the daemon. Below is a very simple
AppleVolumes.system file that will give the Mac users their home directory
and a few other volumes that might have stuff they need.
#
# This file is read before (after if -u is specified) the user's
# AppleVolume file. Add extension mappings and volumes here.
#
/usr/local/samba-sys Sys (F drive)
/home Userdata (G drive)
/usr/local/samba-programs Programs (J drive)
# default translation -- note that CR <-> LF translation is
done on all
# files of type TEXT. The first line turns off translation for
files of
# unknown type, the second turns this translation on.
. BINA UNIX
# . TEXT UNIX
# sounds
.mod STrk STrk
.mid Midi ttxt
.aiff AIFF SNdm
.wav WAVE SNdm
.au ULAW SNdm
# video
.moov MooV mMPG
.mov MooV mMPG
.mpg MPEG mMPG
.mpeg MPEG mMPG
# formatted text
.html TEXT MOS!
.rtf TEXT MSWD
.doc WDBN MSWD
# compressed archives
.bin BINA MB2P
.zip ZIP ZIP
.tar TARF TAR!
.gz Gzip Gzip
.Z ZIVM LZIV
.sea ???? SITx
.cpt PACT CPCT
.sit SIT! SIT!
.hqx TEXT SITx
# graphics
.tiff TIFF JVWR
.tif TIFF JVWR
.bmp BMPp JVWR
.pct PICT ttxt
.pict PICT ttxt
.jpeg JPEG JVWR
.jpg JPEG JVWR
.gif GIFf JVWR |
The other file that you need to edit with NetaTalk is papd.conf. This file
hold the printer information.
# Attributes are:
#
# Name Type Default Description
# pd str ".ppd" Pathname to ppd file.
# pr str "lp" LPD printer name.
# op str "operator" Operator name, for LPD spooling.
#
# Some examples:
#
# On many systems (notably not Solaris), no papd.conf is required,
# since papd shares the same defaults as lpd.
#
# A simple example:
#
# terminator:\
# :pr=lp:op=wes:\
# :pd=/usr/share/lib/ppd/HPLJ_4M.PPD:
#
# Note also that papd.conf can list several printers. |
Installing The Cats Pajamas
Installing
Cats on the Server
Installing Cats on a Linux server can be as simple as copying all the files
and directories from the old server to the Linux server's shared volume
for Cats. The way that I set up out server was to install another drive
in the Linux server to hold the Cats installation. I chose an IDE drive
mainly because I didn't have a SCSI card in the server, didn't have an
extra one handy and I was under an extreme time crunch to get Cats back
online. My intentions were to eventually replace the IDE drive with a SCSI
drive over Christmas break, but the performance has been more than satisfactory,
so we are going to leave the setup alone. I mount this drive as /usr/local/samba-cats
and have the permissions set open to the world by running the command chmod
777 /usr/local/samba-cats -R. This is a security risk, but Cats has told
me that the files must be world writeable and readable for Cats to work
properly. I also have the Samba configuration file set up with a mask of
0777, which will make sure that all files written will be readable by all
the users.
The specific portion of the smb.conf file for Cats is listed here:
[CATS-VOL]
comment = Entire Cats volume for backup
path = /usr/local/samba-cats/
writeable = yes
printable = no
guest ok = yes
public = yes
create mask = 0777
[L-NE]
comment = Cat's root. Map as L.
path = /usr/local/samba-cats/ne
writeable = yes
printable = no
guest ok = yes
public = yes
create mask = 0777
[M-DATA]
comment = Cat's data drive. Map as M.
path = /usr/local/samba-cats/ne/data
writeable = yes
printable = no
guest ok = yes
public = yes
create mask = 0777
[N-DBC]
comment = Cat's program drive. Map as N.
path = /usr/local/samba-cats/ne/dbc
writeable = yes
printable = no
guest ok = yes
public = yes
create mask = 0777
[O-WORK]
comment = Cat's work drive. Map as O.
path = /usr/local/samba-cats/ne/work
writeable = yes
printable = no
guest ok = yes
public = yes
create mask = 0777
[P-HIST]
comment = Cat's history drive. Map as P.
path = /usr/local/samba-cats/ne/hist
writeable = yes
printable = no
guest ok = yes
public = yes
create mask = 0777 |
At the time of this writing, we were still running Cats 2.3, so the major
directories were as follows:
ne----+
|---> data
|---> dbc
|---> work
|---> hist |
While we are currently able to get all of our system onto a 2.5 gigabyte
hard drive, I can see a day when we will have a large enough history that
we will need more space. We could just get a larger hard drive, but an
easier upgrade would be to just add another drive and mount it into the
directory tree. We could actually run four drives for Cats by mounting
a different drive into the ne directory for each subdirectory. By doing
this, data would be running on a drive, dbc would be a drive, work would
be a drive and hist would be a drive. In theory, the performance would
increase, since drive access to data would not slow down history searches,
or read/writes to the work drive.
I have written a CGI Perl script to make it simple for our Business
Department and Customer service department to lock Cats during month-end
closing and reindexing procedures. The script asks for a password, and
then replaces the standard batch files to start Cats with another batch
file that says Cats is locked for closing or maintenance. When they are
finished, they can unlock Cats by running the unlock CGI script. The scripts
are listed here:
Lock Cats:
#!/usr/bin/perl
# ******************************************************
# * *
# * Author: Quinn P. Coldiron *
# * Date: 11-24-97 *
# * Program: This locks Cats *
# * *
# ******************************************************
# Use cgi-lib CGI library for PERL.
require "/home/httpd/cgi-bin/cgi-lib.pl";
#Get the data from the form.
&ReadParse;
print &PrintHeader;
print "<HTML>\n";
print "<HEAD>\n";
print "<TITLE>Finished</TITLE>\n";
print "</HEAD>\n";
print "<BODY BGCOLOR= #b7b7b7>\n";
if ( $in{password} =~ "PASSWORD") {
print "<P><B>Finished.</B></P>\n";
print "<P>Batch files written and CATS is <B>locked</B>.</P>\n";
print "<BR>You may access CATS by going to the M: drive and typing
secret.bat\n";
print "This should only be used for Month-end closing, reindexing and
system repairs.\n";
print "<BR><BR>Quinn.\n";
system ("cp /home/httpd/cgi-bin/cats/lock/*.bat /usr/local/samba-cats/ne/data/");
system ("chmod 777 /usr/local/samba-cats/ne/data/*");
} else {
print "Wrong password\n";
}
print "</BODY>\n";
print "</HTML>\n"; |
Unlock Cats:
#!/usr/bin/perl
# ******************************************************
# * *
# * Author: Quinn P. Coldiron *
# * Date: 11-24-97 *
# * Program: This program copies that cats#.bat files *
# * to the correct location. *
# ******************************************************
# Use cgi-lib CGI library for PERL.
require "/home/httpd/cgi-bin/cgi-lib.pl";
#Get the data from the form.
&ReadParse;
print &PrintHeader;
print "<HTML>\n";
print "<HEAD>\n";
print "<TITLE>Finished</TITLE>\n";
print "</HEAD>\n";
print "<BODY BGCOLOR= #b7b7b7>\n";
if ( $in{password} =~ "PASSWORD") {
print "<P><B>Finished.</B></P>\n";
print "<P>Batch files written and CATS is unlocked.</P>\n";
print "<BR><BR>Quinn.\n";
system ("cp /home/httpd/cgi-bin/cats/unlock/*.bat /usr/local/samba-cats/ne/data/");
system ("chmod 777 /usr/local/samba-cats/ne/data/*");
} else {
print "Wrong password!\n";
}
print "</BODY>\n";
print "</HTML>\n";
|
Configuring
your Windows clients
I have setup our Cats installation to share each required cats directory
as a hard mounted drive letter. The specific portion of the login script
that mounts cats is listed here:
REM CATS drives
net use l: \\unplinux\l-ne
net use m: \\unplinux\m-data
net use n: \\unplinux\n-dbc
net use o: \\unplinux\o-work
net use p: \\unplinux\p-hist |
My cats batch file is here:
PATH=C:\;C:\WINNT;C:\WINDOWS;L:\;M:\;N:\;O:\;P:\
SET DBC_FILEPATH=L:\;M:\;N:\;O:\;P:\
Set DBC_PREP=M:
Set DBC_FILES=140
Set DBC_PGMSIZE=65024
Set DBC_CMDLINE=OLD
SET DBC_XKEYS=ON
Set DBC_COMPAT=DOS
Set DBC_PORT=24
SET DBC_DBCPATH=N:\
M:
DBC.EXE |
I have also followed the suggestions on the Cats web site http://www.tcpj.com
for specific settings for Windows 95. I have found that all of these do
help in getting Cats to run better.
Configuring
the DOS emulator to run Cats
Linux has a very interesting program called DOSEMU which creates a ``DOS
box'' that can run many DOS applications, including MS-DOS, PC-DOS, DR
DOS, Open DOS, Windows for Workgroups 3.11, the Novell Netware client and
many more. I had problems at first getting DOSEMU to run programs on the
redirected drives unless I called them by the full name (go.bat instead
of go) but tracked this down to the version of DOS that I was using. I
was using Novell DOS 7.0 but switched to MS-DOS 6.22 on the advice of Hans
Lermen (one of the DOSEMU developers) and this fixed the problem. He said
that this has been reported many times and it seems to be a bug in the
command.com code that many versions of non Microsoft DOS use.
DOSEMU uses an image file of a hard disk to emulate a DOS hard drive
so you do not need to have a DOS partition. Using the /var/lib/dosemu/setup-hdimage
program will step you through making a basic hdimage file. The only required
item is a bootable DOS 6.22 floppy disk with whatever DOS tools you think
you might need. I included EDIT.COM and QBASIC.EXE. After running through
the setup-hdimage program, start the emulator with xdos or dos, depending
on if you are in X-Windows or not. The default setup gives you the Linux
hard drive as DOS drive D:\. To copy the programs I wanted off the floppy
to the hdimage file, I opened another xterm window and mounted the floppy
to /mnt/floppy, then switched back to DOSEMU, changed to D:\mnt\floppy
and copied EDIT.COM and QBASIC.EXE to C:\. I could now run the MS-DOS editor
to edit the config.sys and autoexec.bat files. If I wanted, I could also
write a quick QBASIC program.
DOSEMU gives you a utility called LREDIR which redirects Linux directories
to DOS drive letters. Below is the AUTOEXEC.BAT that I use with DOSEMU
to give me the drive letters for Cats and for Robotronics.
@echo off
path=c:\;l:\;m:\;n:\;o:\;p:\
prompt $p$g
rem set temp=c:\temp
lredir l: linux\fs\usr\local\samba-cats\ne
lredir m: linux\fs\usr\local\samba-cats\ne\data
lredir n: linux\fs\usr\local\samba-cats\ne\dbc
lredir o: linux\fs\usr\local\samba-cats\ne\work
lredir p: linux\fs\usr\local\samba-cats\ne\hist
lredir t: linux\fs\usr\local\samba-sys\programs\nesb
c:
menu.bat |
This autoexec.bat file loads the redirected drives and displays a menu
which allows the user to select the DOS application they want to run (CATS
and Robotronics). I have set the dos emulator as the shell, so that as
soon as the Mac users or remote users telnet into the Linux server the
DOS emulator is started and they get the main menu. When they exit the
DOS emulator, they are disconnected from the server.
The
RAID that we chose to purchase was a kit that contained a SCSI RAID controller
and subsystem storage cabinet from Distributed Processing Technology.
The SCSI card is a PCI card with a caching module added to it. The cache
module has four SIMM slots on it and will accept any standard 32 pin SIMM
up to 16 meg each for a total of 64 megabytes of cache. The card comes
with a four meg module already installed, and that is what we currently
are using.
The storage subsystem requires you to supply your own drives and comes
in two style. One supports narrow SCSI drives and the other supports wide
drives. We are using the narrow drive cabinet, mainly because I already
had three drives that I wanted to use. Installing the drives can be tricky,
as the data cable is not color coded and I could not tell what wire was
for pin one. The first time around I had the drives installed backwards,
but nothing was hurt. I called the tech support line and they were very
helpful in getting the problem fixed.
After installing the card in the server, the next step is to configure
the RAID with the RAD level of choice. We chose to run RAID level 5. While
Linux does have built in drivers for the DPT controller card, DPT does
not offer Linux utilities to configure the unit. What I did was temporarily
plug a 200 meg IDE hard drive into the server to boot from and ran the
DOS configuration utilities which are graphical and easy to follow. Using
the mouse, I selected the three drives that I wanted to include in my RAID,
then selected the RAID level I wanted, saved the configuration and shutdown
the computer. I then unplugged the IDE DOS drive and reconnected the IDE
Linux boot drive.
I kind of cheated when I installed the driver for the SCSI card by rerunning
the Linux setup program. I had other things that needed fixing, so I thought
this would be the best way. I could have just added the daemon by using
the tools in the control panel as well or by typing insmod eata-dma
at the command prompt and the driver would be loaded and I could see
the report that the system now recognizes my SCSI card and RAID. During
the installation, select YES when asked if you have a SCSI card and select
correct driver (EATA-DMA) for the card you have. When you are finished
and reboot the computer, you will see the RAID initialize and report the
settings you configured under DOS, then the kernel recognizing the card.
Now, you need to create a partition and format the drive. To make a
partition, use the fdisk command and follow the menu to make a Linux primary
partition. Formatting the RAID is as easy as formatting any other drive.
Remember that the system sees your RAID as a single, large disk. To format
it in Linux, issue the mkefs2 /dev/sda1, or whatever SCSI drive it is.
To actually use the disk after formatting, you need to mount it someplace.
I wanted to use this disk for the home directories of our users, so I mounted
it as /home/raid. But, whenever I added a user, they were still being added
to /home and not on the RAID, so I edited the /usr/sbin/adduser script
(which is just a Perl script) and changed the home directory location to
/home/raid. Now, whenever I add a user, they are added to the RAID.
Daily administration
I have a SCSI Hewlett Packard SureStore 6000 4mm DAT drive that I am setting
up for backup duties for our Linux server. Currently, I am backing up all
data through Samba to our Windows NT server using
another SureStore 6000 tape drive and Cheyenne Arcserve software. I
have also been known to make a quick backup to the RAID using tar. Tar
is a simple utility that has been around Unix almost as long as Unix has
been around.
To make a tar backup, just issue the following command:
tar cvf archivename.tar /directory-to-archive
This will create a tar file named archive.tar of the contents of the
directory directory-to-archive. While this works fine, the resulting file
might be very large because we did not apply any compression. By
modifying the command to look like this:
tar cvzf archivename.tar.gz /directory-to-archive
We compress the tar file with gzip after the file is made. At a later
date, we might want to view what is in the tar file, so we can issue the
tar tvf archivename.tar.gz to list the files in the archive.
While backing up to disk is OK for a temporary thing, you should always
backup to tape for critical data. Linux supports two types of tape drives.
The first is the style that connects to the floppy drive
controller, like the Colorado drives and Iomega Ditto. The other style
connect to a SCSI controller. Floppy tape drives have the device names
of /dev/ft0, dev/ft1 and so on. SCSI drives are /dev/st0, /dev/st1 and
so on. These devices are "rewinding" devices which rewind the tape when
the operation is completed. IF you are archiving more than one session
to the tape, then use the non-rewinding devices /dev/nft0, /dev/nrft1,
/dev/nst0, /dev/nst1 and so on.
After writing the archive to tape, you can use the mt (magnetic tape)
command to rewind, retention and find sessions on tape. The table below
shows the commands.
mt /dev/nft0 rewind
mt /dev/nft0 retention
mt /dev/nft0 fsf 1 skips the current session to find the next session
on tape.
To use the mt command, you must use the non-rewinding devices.
Using tar to make backups has its good points and its bad points. On
the bad side, neither tar or gzip are fault-tolerant. Compressing tar files
with gzip will greatly reduce the amount of space on the backup
media, but if even one block of the archive gets corrupted, which can
happen on tapes, the entire file can be useless. Usually, you will be able
to retrieve all data up to that point, though. A better solution is to
use a "real" backup system such as BRU (Backup and Restore Utility) that
comes with a purchased version of RedHat Linux 5.0. Backup systems usually
compress each file individually, so that if the media is damaged, you will
not usually lose the entire archive.
BRU has both a command prompt interface and a graphical X-Windows interface
and is included with RedHat 5.0. BRU offers automated backup scheduling
and scripting, so it is very easy to setup a simple but effective and reliable
backup system. I find the system as easy to maintain as ArcServe on Windows
NT.
Linux has a very easy to use scheduler program called cron that will run
commands, scripts or programs at the scheduled times. To edit the list
of events, issue the crontab -e command. This will start the default editor
(usually vi, but I changed mine to joe). When you exit the editor, cron
will install the new config file you just edited and schedule all the jobs.
You can view the schedule by issuing the crontab -l command:
SHELL=/bin/bash
PATH=/sbin:/bin:/usr/sbin:/usr/bin
MAILTO=root
# Run any at jobs every minute
# * * * * * root [ -x /usr/sbin/atrun ] && /usr/sbin/atrun
# run-parts
# 01 * * * * root run-parts /etc/cron.hourly
# 02 1 * * * root run-parts /etc/cron.daily
# 02 2 * * 0 root run-parts /etc/cron.weekly
# 02 3 1 * * root run-parts /etc/cron.monthly
# Remove /tmp, /var/tmp files not accessed in 10 days (240 hours)
# 41 02 * * * root /usr/sbin/tmpwatch 240 /tmp /var/tmp
# Remove formatted man pages not accessed in 10 days
# 39 02 * * * root /usr/sbin/tmpwatch 240 /var/catman/cat?
#############################################################
# WWW logs. I run 2 so I can compare results.
#############################################################
# Run web one web log utility 0 0-23 * * * /usr/bin/log
02 1 * * * /usr/bin/log
# Run the other web log utility 0 0-23 * * * /usr/local/mkstats/mkstats.pl
-c mkstats.config
02 1 * * * /usr/local/mkstats/mkstats.pl -c mkstats.config
#############################################################
#############################################################
# Live stream management
#############################################################
# Create xdm file for live stream for Sports Nightly (5:45 pm)
45 17 * * 1,2,3,4,5 livestream-on
# Kill xdm file for live stream for Sports Nightly (8:10 pm)
10 20 * * 1,2,3,4,5 livestream-off
# Create xdm file for live stream for Saturday games (7:00 am)
0 7 * * 6 livestream-on
# Kill xdm file for live stream for Saturday games (10:00 pm)
0 22 * * 6 livestream-off
# Check the 3.0 server to see if it is running and not dead! (every
minute)
1-59 * * * * /usr/local/streamworks-3.0/checkSWserver
##############################################################
# Check to see if network volumes are mounted (at 10:00 p.m.).
# These need to be mounted since this machine performs the
# backup at 11:55.
0 22 * * 1,2,3,4,5 checkmounts
# copy BIP from Intrepid to exeter (WWW)
0 23 * * 1,2,3,4,5 /usr/local/bin/mvbip
# backup userdata from intrepid
55 23 * * 1,2,3,4,5 bu-userdata
# backup CATS
55 23 * * 1,2,3,4,5 bu-cats
# backup Marketing
0 3 * * 1,2,3,4,5 bu-marketing
# mail orders to quinn
0 8 * * 1,2,3,4,5 /usr/local/bin/mailunporders.pl |
Each entry has a specific configuration to follow. If you want the command
to run every day at 1:00 AM, specify the minute as 0 and the hour as 1.
The other three fields should be asterisks, which means ``every day and
month at the given time.
You might notice the entry
# Check to see if network volumes are mounted (at 10:00 p.m.).
# These need to be mounted since this machine performs the
# backup at 11:55.
0 22 * * 1,2,3,4,5 checkmounts
This calls a script I wrote to check that the NT server is mounted so
I can backup all data on it. I mount the server using the smbmount command
which allows a Linux machine to mount shares from a Windows machine. This
script just verifies that a certain file or directory is actually at the
mount point. I use these ``reference'' files for checking purposes, so
they are read-only, so they can't be accidentally deleted by users. The
script is listed here:
#!/bin/sh
# Cronjob to remount network drives if they are not mounted.
# Author: Quinn P. Coldiron
if [ -z "`ls /mnt/exeter | grep InetPub | grep -v grep`" ]
then
umount /mnt/exeter
/mnt/mountexeter
echo "Exeter remounted `date`"
fi
if [ -z "`ls /mnt/intrepid-f | grep BLINE | grep -v grep`" ]
then
umount /mnt/intrepid-f
/mnt/mountintrepid-f
echo "Intrepid F remounted `date`"
fi
if [ -z "`ls /mnt/intrepid-g | grep QC | grep -v grep`" ]
then
umount /mnt/intrepid-g
/mnt/mountintrepid-g
echo "Intrepid G remounted `date`"
fi
if [ -z "`ls /mnt/intrepid-mrktdept | grep KK | grep -v grep`" ]
then
umount /mnt/mountintrepid-mrkt
/mnt/mountintrepid-mrktdept
echo "Marketing remounted `date`"
fi
echo "All network volumes mounted." |
Replacing
your Desktop OS with Linux
Places to go:
I have wanted to make Linux my desktop operating system for a long time,
but I couldn't because I needed to be able to run the following applications:
Microsoft Word, WordPerfect, Microsoft Excel, Microsoft Access, our internal
mail system (Pegasus), Microsoft Access and Microsoft Visual Basic. I have
recently narrowed the list of required applications that do not have a
Linux counterpart down to Access and Visual Basic, which we will analyze
later.
I have found that, for the most part, I can replace Microsoft Office
with Applixware. Applixware is an office suite for Linux (an many other
Unix platforms) that can read and write Word and Excel files, which allows
me to share documents with the rest of the press. While I still cannot
read Access databases, I am working out a solution for that which we will
discuss later.
Applix Words
-
· Live links to Applixware or third-party applications
-
· Mail-enabled compound document technology
-
· Landscape, portrait and merge printing
-
· Multiple undo and redo
-
· Hypertext with optional HTML output
-
· Forms editor
-
· International dictionaries, thesauri and spell checkers
-
· Conditional text and cross-referencing; find and replace
-
· Embedded equations and calculation support
-
· Multiple typefaces, type styles and sizes
-
· Highly graphical user interface
-
· Tables and frames; borders and shading
-
· Multimedia support including audio and video
Applix Spreadsheets
-
· Live links to other Applixware and external applications
-
· Calculation-based attributes
-
· 3D spreadsheets and charts
-
· Integration of external functions
-
· Built-in string, financial, mathematical, and statistical functions
-
· Goal seeking
-
· Multiple named views
-
· Dynamic inter-spreadsheet links
-
· Live graphs and charts
-
· Editable graph styles
-
· Print preview
-
· Borders and shading
-
· Drag-and-drop moving of cells
-
· Projection tables
-
· Relative and absolute cell references
-
· Built-in database functions
-
· Built-in shared library, RPC, and shell command mechanisms
-
· True minimal recalculation
Applix Presentation Graphics
-
· Feature-rich palette, fill patterns & drawing tools
-
· Horizontal and vertical shearing
-
· User-definable fill patterns, brush styles and shapes
-
· Unlimited color support and point sizes
-
· Rotating and scaling options
-
· Drop shadows
-
· Text wrapping
-
· Image digitizing
-
· Pixel editing
-
· Managed layers and animation
Applix Mail
-
· Fully mail-enables all Applixware products
-
· Personal and global user lists, distribution lists and aliases
-
· Sorting, filing and querying on incoming messages
-
· Automatic conversion of messages/documents to recipient's preferences
-
· UNIX sendmail transport and MIME compliant
-
· Shared folders
Applix HTML Author
-
· Availability of a wide range of basic and advanced HTML concepts
-
· More than 25 standard HTML styles for headlines, subheads, lists
and text
-
· Auto-conversion of Applix Words styles to standard HTML styles
-
· Auto-conversion of Applix Graphics and Applix Presents to GIF,
including linked or embedded graphics
-
· Auto-conversion or creation of tables
-
· Full control over background color, text and hyperlink colors
-
· Auto-bulleting and auto-listing functions
-
· Dialog boxes and pull-down menus for all attributes and activities
-
· Straightforward linking and editing of existing GIF files
The Extension Language Facility (ELF) and Macros
-
· Robust interpretive programming language
-
· TCP/IP socket interface and remote procedure calls (RPCs)
-
· Interactive debugger, compiler/interpreter
-
· Arithmetic, string and Boolean operators
-
· Over 2500 built-in macros. Time-saving features for all users
-
· User-definable menu bars, dialog boxes and keybindings, menu-bar
editor across all Applixware products
-
· Keystroke and mousepick recorder
-
· Live linking and launching of external applications from Applix
Words,
-
· Spreadsheets, Presents, and Mail.
-
· User-definable ExpressLine icons for automating tasks
-
· Incremental zoom
Changes from Previous Version
This new version features advanced HTML authoring tools for adding pages
to your website simply and directly. It also has dramatically improved
filter technology enabling you, for example, to import and work on Word
or WordPerfect files and export back in those formats. If you want the
``real thing'', Corel has version 7.0 of Word Perfect available for Linux.
The graphical user interface for Linux (and Unix in general) is X Windows.
A typical X Windows setup is shown below. This system is running the Common
Desktop Environment (CDE) window manager. X Windows is divided into two
subsystems consisting of a server and a client and you are free to change
either of these as your want. The main reason for changing an X server
is to gain better speed and better support for your video cards and monitors.
The main reason for changing window managers is to get the look and feel
you desire. You can not change the server or window manager under any of
the Windows products, because Microsoft has decided the look and feel you
get. The closest they get is the Plus! pack and its themes.
Another possibility , which will save money and breath life into your
old 486's is to install Linux on them and use them as a NC (Network Computer).
Linux's GUI is X, so it is perfect for an X terminal (with either another
Linux machine as the server, or any other Unix system) and you can run
Insignia Solutions Inc.'s Keoke client under Java in order to turn your
Linux workstation into a thin client that runs Windows (virtual NT) applications.
As a rule, Linux performs radically better than Windows 3.1 given the
same amount of RAM. Linux can run complete with a graphical desktop on
a 386 with 4MB of RAM, if you're patient. Add Netscape Navigator, and you
can get away with a 486 and 8MB of RAM. Consider 16MB of RAM a performance
sweet spot, especially if you use Communicator. Linux also has unimposing
disk space requirements. The bare-bones Caldera graphical client uses about
68MB of disk space. You'll want to install a few more packages than that
(Netscape, Java, and perhaps a friendlier window manager than the default
Fvwm), and you'll need at least a 32MB swap partition. When you consider
all the factors, a 200MB disk is plenty for most desktops.
Appendix A
RedHat
5.0 Installation Guide
Appendix B
Appendix C
Copyright © 1998, Quinn P. Coldiron
Published in Issue 29 of Linux Gazette, June 1998
"Linux Gazette...making Linux just a little more fun!"
Revisiting VIM
by Andy Kahn
April 29th, 1998
Vim stands for "VI Improved", and certainly,
it a very much improved version of the old text editor, vi. It's been a
while since the gazette had an article on vim (over a year to be exact!),
and a lot has changed since then, including a major version release. I
decided to cover some of the new features (as well as some older features)
that I find extremely useful in vim, but not in vi.
Features
First of all, let me just run down some of
the big features of the latest version of vim:
Syntax highlighting
Win32 GUI version
BeOS version, including GUI
MacOS GUI version
VMS version
Built-in scripting language
Perl and Python support
Unlimited undo
Multiple windows
...and a ton of other good stuff
Syntax highlighting
Personally, I found the syntax highlighting
to be one of the most useful features of vim. Syntax highlighting (or coloring,
as some may call it), colors text according to their attributes. For editing
code, this allows you to have different colors for commented text, keywords,
numbers, etc. You may not think much of it, but believe me, after staring
at code for long periods of time, all the text on the screen starts looking
pretty much the same. It certainly helps to have some color differentiate
between actual code, and comments in the code! A picture is worth a thousand
words, so here's a screen shot of my vim setup editing main.c from the
vim source:
You may notice the curious string on the
very first line of the file: "vi:set ts=8 sts=4 sw=4:"
This is just a little formatting shortcut. If you write code that other
people may look at and/or edit, if they also use vim, then the code will
be properly indented as you intended it to be! This is just like the magic
strings people use in emacs: "-*- Mode: C++; tab-width: 4; indent-tabs-mode:
nil; c-basic-offset: 4 -*-" to make indentation
look consistent.
Gui versions
As for all the wonderful GUI versions of vim,
here's a screenshot I found at http://polder.ubc.kun.nl/~rhialto/be/vim-5.0s-screen1.gif
showing off the BeOS version:
Here is a BIG screenshot of the Unix version
of vim with four different looks (vim in an xterm, vim using Athena, vim
using Athena with Xaw3d, and vim using Motif (for Linux users, Vim also
works with Lesstif)). Click on the image for the full size version:
There are plenty more screenshots here.
Built-in Scripting
The built-in scripting language is a small
language (as opposed to Perl and Python) that let's you do some simple
things in your vim startup file (.exrc or rather, .vimrc). For example,
the simplest thing to do is to check for a version or feature:
if version >= 500
" Switch on syntax highlighting.
syntax on
if has("cscope")
set csexec=/usr/local/bin/cscope
set csto=0
set csta=1
set csverb=0
cs add cscope.out
set csverb=1
else
map ^] g^]
endif
endif
Visual Text Selecting
A feature which is present even in the previous
version of vim that I use frequently is its "Visual" capability. By hitting
"v" when in command mode, you can highly lines and words and then perform
just about any normal vim operation on the selected text! This includes,
deleting, copying, pasting, running more ":ex" commands, and my favorite,
reindenting. For example, let's say I highlighted the following code:
If I hit ">" (that's the greater-than sign,
or Shift-.), the result will look like this:
Or if I were to hit "<" (the less-than
sign, or Shift-,), I get this result:
If I really wanted to, I could highlight
the entire function, and run then run it through the "indent" program:
Before:
After:
C and C++ tags
Another feature programmers will find handy
is vim's ability to deal with multiple tags. Vim comes with "Exhuberant
Ctags", and with it, you can store multiple definitions in the same tags
file. Once in vim, you can do use ":tselect" or ":tjump" on a tag, and
vim will present to you a list of the multiple tag entries. Just select
from the list, and vim will take you there as it normally would with a
single tag entry!
There's More!
Of course, I could go on and on about all
the little (as well as big!) things that make vim such a great editor.
But I won't bore you with the details. :) You can go read
about them yourself on vim's homepage: www.vim.org.
There's plenty of new things being worked on and added all the time, including
more features in the various GUI versions (contact me if you are interested
in doing a GTK and/or a QT version!), ports to other platforms (including
the Amiga), and other nifty features.
There are certainly a lot of text editors
out there, and if you're a vi user, you should definitely consider using
vim if you aren't doing so already!
Andy works at Digital Equipment Corporation doing
Digital Unix filesystems kernel development.
He thinks he's just hacking away at more and more C code,
and in his copious spare time, he hacks on lots of other
things, including all the trees in his neighborhood.
Feel free to send him
email.
Copyright © 1998, Andy Kahn
Published in Issue 29 of Linux Gazette, June 1998
"Linux Gazette...making Linux just a little more fun!"
A Linux Journal Preview:
This article will appear in the August issue of Linux Journal.
Sun Joins Linux International
In May, Sun Microsystems joined Linux International. In a
year where Netscape has released their source and many companies have
announced that their products will be supporting Linux, I felt Sun's move
was an interesting enough development to want to know more. Therefore, I
did a short e-mail interview with Charles Andres, a Group Manager in
Market Development Engineering at Sun Microsystems. Here's what he told me.
Margie:Why has Sun made the decision to join Linux International?
Charles: Sun Microsystems is responding to renewed interest in
running Linux on its UltraSPARC products, such as the Ultra 5.
SPARC products have always been designed to run UNIX extremely well.
Linux runs well on UltraSPARC platforms.
It is important to note that this move in no way diminishes Sun's support
for Solaris, a proven reliable scalable operating system. The Solaris environment
will still be provided with all SPARC systems and is considered by us to be
the best operating system for enterprise and network computing.
Margie: Is Sun planning to have Linux support for all its products?
Charles: Sun Microsystems is not planning on selling any products that are bundled
with Linux. Sun bundles Solaris with every workstation and server
it currently ships. There are also no plans to provide support for
Linux directly. However, there are a number of Linux vendors that
support a variety of platforms. We are working to ensure that these
vendors include UltraSPARC platform support for their Linux products.
Margie: Does this move represent a shift in policy for Sun? Last year, we
asked for a picture of a SunSPARC workstation to use on our cover, and
were refused because ``Linux is a competitor.'' (We used a Ross SPARCplug instead.)
Charles: Sun Microsystems has never had an official policy regarding Linux up to now.
As stated above, Sun Microsystems has gone from having no policy regarding
Linux, to helping to ensure that Linux runs on SPARC by assisting companies who
sell supported versions of Linux.
Margie: How does Sun feel about the ``Open
Source'' movement? (Prominent in the news, because of Netscape
source release.)
Charles: Sun Microsystems has a long tradition of supporting open standards,
typically through standardized interfaces, many of which Sun has invented. Providing
source code may be appropriate in some specific instances, but typically works
well only in situations where trademarks associated with the source code are licensed.
Compatibility, consistency, reliability and upgrades require a
business model that can finance the effort required to provide them.
Users who want the freedom of Open Source take on the responsibility of
maintaining their own source code, but cannot guarantee consistent results
with other variants. This could become a problem for Netscape source variants if
they are not uniquely identified. This is why we feel brand protection
through licensing
is so important.
Margie: Some people feel that Java should be made Open
Source. Any chance of that happening?
Charles: Source for the Java language is available to anyone who signs the Java
license which is free for non-commercial use. This is done to allow
Java to run anywhere, and to avoid problems that could occur when
source is modified to produce variants that are not consistent with
the Java language specification.
Margie: Anything else you'd like to add?
Charles: We look forward to working with you and the Linux community
to promote the advantages of UNIX and Linux on SPARC in the future.
Margie:Thank you for your time.
Copyright © 1998, Marjorie Richardson
Published in Issue 29 of Linux Gazette, June 1998
"Linux Gazette...making Linux just a little more fun!"
Tom's 2 cent Tips
The notes listed below document the author's "show stoppers" which were
made as he learned UNIX, after working on DOS, VMS, and other systems. There
is a small chance that you will make exactly the same error, and this document
will help you to solve it. What is far more likely is that you will skim
through it, and hopefully learn one very important thing:
Almost all errors are trivial, and result from your understanding a Unix
function *almost* completely. Gross errors in understanding are very rare,
although when you hit a show stopper, you usually get the initial impression
that you are hopelessly in left field and will never understand this cryptic
operating system. Not True!! *Do not give up*!
I suppose that you have already guessed it, but the FAQs, man pages and
emacs info documentation comes with Linux, and *really* help out. You have to
really dig: there are bookshelves of documentation in the above sources. You
will probably learn more about certain topics than you wanted to, but after a
while all this knowledge begins to look good on your resume. While I have
tried to avoid overlap in this document, some does exist. It should give you
pause that there is so little overlap! A modern operating system is a complex,
many faceted beast. Take it a facet at a time and you'll get around it!
UNIX is largely free of the system crashes that plague DOS and the
MAC. This is because a user account is almost incapable of accessing the
system resources required to crash the system. When you're running in DOS or
MAC mode, you (or more often, programs that you run) can crash the system. I
once complexly wiped my hard disk while running Borland's C++ compiler. I have
never had this happen with Linux. I've never, in five years, crashed the
system so badly that I had to reset. Granted, some functions (X windows and
the modem) required a reset, but I could always get to a root virtual terminal
to shut down gracefully. I've merrily crashed VMS, other Unicies, and of
course, anything Microsoft has ever produced, from DOS 3.3 to NT. Linux is
robust.
I suppose no introduction is complete without a testimonial. Here goes: I
mentioned above that I had worked on a number of systems before embracing
Unix. Unix (especially Linux) is the best system I have *ever* worked on.
Give it a chance: it takes a while to collect a "critical mass" of Unix
commands to make the system really fly, but once you do, you'll become one of
those insufferable Unix propeller heads who claim (truthfully) that nothing
else even comes close!
Please Note: The author has made every effort to insure the correctness of
the information which follows. However, there are NO warranties, expressed or
implied, for this information. In other words, if something goes wrong, it's
your problem.
Contents:
Alphabetical list of utilities with one or more tips with them:
adduser
You can only run this from root, but it is an essential command. Almost
all of your time spent in Linux should be spent in a user account of your
own creation, as this account is prevented from executing disastrous
commands such as rm -rf /* (This cleans your disk in a disastrously
complete fashion.)
MORAL: Always run in a user account, not root unless you are doing some
system administration which will only work in root.
ar
Ar creates a library file, which, after you get a utility program you'll
be using in other programs, allows you to easily access the object files
of that program. The files are created by the following command:
ar -r libArchiveName.a objectfile.o
ArchiveName is, by convention, named libArchiveName.a. However, you refer
to in your make file only by ArchiveName. e.g
LIBFILES = ... -lArchiveName ...
Backing up.
Having your system crash and not loosing valuable data is what separates
the computer pros from the also rans. Here's how I do it.
All of the software on my system is safely contained on the CD that I used
to load it in. There's no reason to back up this stuff. CDs are more
stable than any tape or disk backup I know of.
I only back up files that I have fiddled with. My programs, configuration
files, documents, etc. I have a script file, sall (save all) which goes
to each directory that I have stuff in, tars it, gzips it and then saves
it to floppy.
This stuff all fits on one 1.44 Mb disk. It represents about 730 pages of
single spaced typewritten output. That's a lot of typing. Most books
aren't that big. If you have more stuff than this, I'd suspect that 80%
of it is stuff you haven't touched in a year. You can back it up to a
disk, put the disk in a safe place and pretty much forget it. Of course,
if you gzip the result, you can usually more than triple the amount of
stuff you back up.
I have 15+ disks which I keep my backups on, and back up at the end of any
day that I have done a substantial amount of input. This gives me access
to a month or more of past versions.
You'll find your own way in this. The important thing is to *do* it.
Then you can feel almost smug when you hard disk finally dies.
bash (and ksh and sh)
To set an environmental variable with bash use the following syntax:
VARIABLE=value
For example, to tell bash
that your are a vt100 type terminal, enter:
TERM=vt100; export TERM
NOTE: There are no spaces around the equal sign. This is true for
all bash commands, not just setting environmental variables.
Remember this and be saved frustration down the road.
C
- As Unix is currently configured, there is no easy way to get a single
keystroke without using curses or changing the terminal characteristics.
Your users will just have to get used to hitting Enter after an input. If
they can't, uses curses or the GCC C manual (actually a superb reference
for C libraries well worth the $50+ bucks!)
- After you have output to an opened text file, it is a good idea to send a
fflush(stdout) command. This will flush the buffer and keep you from
overflowing it if you get over 2048 characters in it, which is easy to do.
- To use math.h functions in a c program:
Link in the math libraries by typing:
gcc source.cxx -lm
Math libraries MUST be linked in last!!! Old UNIX linker convention!
- When declaring pointers, every variable must be proceeded by an asterisk!
int *v1,
v2,
v3;
Results in compiler complaints of bad unary operator arguments! Correct:
int *v1,
*v2,
*v3;
- To capture the output of a compile which is causing problems, and
outputting reams of digital vomit, use this construct from a sh based
shell like bash:
gcc -c flaw.cxx &> TextCapture
or
gcc -c flaw.cxx 2> TextCapture
The errors will be captured in TextCapture.
- A static variable is initialized only once in a function. All other calls
to that function result in the existing value of the variable being used.
- Shifts in most Unix C compliers are actually integer divides and
multiplies by 2. Never mind what the ANSI spec says:
This code gives problems:
long n = 0x80000000;
for (i = 0; i < 24; i++) printf("\n n is now %lx.", n >> i);
n must be declared as an unsigned long for this to produce reasonable
results. The fact that n starts negative fowls the compiler up. This
also indicates that right and left shifts are implemented as divide and
multiply by 2 with the GNU C++ compiler.
- This is perhaps my favorite subtle error. If I only had a dollar for every
hour I've spent searching for this self imposed klutziness...
for (i = 0; i < upper_limit; i++);
{
this = cant_happen;
the_loop = wont_execute;
}
See the semi-colon at the end of the for statement line? The program
pauses for an empty loop of upper_limit cycles, and then proceeds to do
just the first installment of the loop and nothing else. It's quite easy
to to, too, even after you've been bitten a few times by it.
- You can core dump a program sooner than quicker by writing too much stuff
into a string, so that it doesn't end with that all important 0. e.g.:
double age;
char oops[52];
int len; ...
sprintf(oops,"The age of the universe in nanoseconds is %f.\n",age);
len = strlen(oops);
The fragment will die at the strlen call, as the string is longer than 50
characters, even if it is 10 character in the sprintf statement. The age
of the universe in nanoseconds is about 19 characters long.
- This code will pass a file pointer (tfile) to a function:
#include <stdio.h> /* fclose, fopen, printf.*/
#include <stdlib.h> /* exit. */
void main(int argc, char* argv[])
{
/* Function Prototypes:*/
int openfile(FILE** tfile);
/* Variables:*/
FILE *tfile; /* Test file.*/
/* Begin:*/
printf("Starting program. tfile = %p.\n", tfile);
openfile(&tfile);
printf("Back in main. tfile = %p\n", tfile);
fclose(tfile);
}
/* Open the file and return the pointer.*/
int openfile(FILE **tfile)
{
*tfile = fopen("junk","wb");
printf("Tfile just opened. tfile = %p, *tfile = %p.\n",
tfile, *tfile);
return 1;
}
- This code will allow you to reference an array of characters as an array
of longs without using a union:
int bozo(void)
{
void use_long(long *array); // Function prototype.
char *array; // The character array.
use_long((long*) array);
}
void use_long(long *array);
{
// Reference the array as longs here.
}
- Profiling:
Compile with the flag -pg (for gprof compatible output).
Link with the -pg flag AT THE END OF THE LINK LIST. e.g:
gcc -o run_time_image my_main.o my_other_stuff.o -pg
Even then, don't expect miracles. This does not work on an mpeg2 package
I found on the net.
- Reading in a globbed (wildcarded) file list:
If you want you program to work on all files in a directory, you can
enter "myprog *". Argc will count the number of files out there, and
argv will be the char **list of their names.
- The code
string1[i++] = string2[i];
Will take the nth component of string2 and put it the into the nth
component of string1, then increment i. This is how GCC and the SGI C
compiler do it.
The Motorola C compiler takes the (n + 1)th component of string2 and puts
it into the nth component of string1. I gets incremented *before* the
assignment. Safer is to just use this code:
string1[i] = string2[i];
i++;
- The code
if (index++ == NR_PTS) index = 0; // Fails to implement a circular buffer.
Does not implement the desired buffer. Let's say that NR_PTS is 100, and
index is 99. The comparison is made when index is 99. Index is not reset,
by then it is set to 100 by the ++. Next time, of course, the index will
be reset to 0, but by then, it's overwritten whatever was in buffer[100],
which is the 101st entry in buffer, a 100 int (or whatever) array.
use this instead:
if (++index == NR_PTS) index = 0; // Implements the circular buffer.
- Occasionally, if you allocate a *huge* array (I needed one 10.7 MB to
make this one happen) the program will bomb as it tries to pass the array
to another function. For example:
char moby[20000000]; // A really big text file.
There simply wasn't enough room on the C/C++ stack to hold the array,
and the program bombed as soon as it tried to access it. The compiler,
of course, didn't complain.
The fix is to malloc (or new, in C++) the array:
char *moby; // A really big text file.
moby = (char*) malloc(20000000);
if (moby == NULL)
{
printf("Hey! I'm not big enough to hold moby!\n");
}
- When it works on one machine and not on others, or in the debugger and
not out of it:
You might well be not initializing your variables properly. Sometimes
one machine will just happen to initialize a variable to a non lethal
value, and the others won't. See inexplicable errors item 3 as well.
- Inexplicable errors:
Occasionally, you will face very odd errors. A function works perfectly
*most* of the time. The rest of the time, it has very strange errors.
Variables seem to change value in a capricious way, and your frustration
index soars off of the charts. If you're a beginner, you decide that
programming is beyond you, and give up. Don't despair, quite yet. There
are a few tricks, not written in any book that I have seen, that I have
developed over the years to help you over these rough spots. In general,
try these in the order given.
- Rewrite your code until it is remorselessly neat.
- Step through it line by line with a good debugger (I recommend
GNU's GDB for C code. It's a bit flaky (1998) for C++).
- If these steps did not fix the problem, try recompiling
everything with a command like:
rm *.o // Important!
make // Or whatever compilation command you use.
- If you have inconsistent program results, so that the program
works most of the time, and inexplicably fails occasionally,
carefully check to see that all of your variables have been
initialized properly.
- Sometimes the memory can be corrupted by new routines not fitting
into word boundaries on your machine. Granted, this is *not*
supposed to happen, but it does anyway, even in the best
compilers and linkers. Try declaring arrays to be 1 index larger
than they should be and see if that fixes it. (This is getting to
be a rare C error (1998)).
- There are times when the program does not misbehave in the
debugger, and if you put a few diagnostic printfs in it to further
check it out, it still does not die. These temporary measures may
need to be made permanent as the extra variables you created to
let you see what is going on have pushed the memory usage
boundaries of the function to a more robust spot (i.e. to a word
boundary).
- Once you think you've fixed the problem, *TEST EVERYTHING* before
you release anything.
- Keep at it. With practice, you can dumb yourself down to the
intelligence level of a compiler. Good Luck!
chmod
The command chmod XXX .* can have unforeseen after effects. It affects
the directory you're in as well as the files in that directory! You might
find that only root can access the files, and then only after chmoding
them back to where they were supposed to be.
cpio (not often used, most Unix users use tar instead)
To use cpio, for backups, specify:
find (path name) [-name] | cpio -oc > (destination file and directory.)
To extract a cpio file:
cpio -i [-F (full file specification)] [-r rename files]
cshrc
To change the erase key from ctrl h to <-, one has to add the line:
stty erase \x7F
To the .cshrc file. Unfortunately, the C shell interpreter does not
understand the sequence \x7F, and I needed to write a short C program to
insert the byte with value 127 (7F hex) at the end of the file.
To set the terminal from 'console' or 'Linux' to vt100 (needed by elm (a
mail handling utility)) on an SGI, put this line in your .cshrc file in
you SGI home directory:
eval `tset -s -Q vt100`
If your etc/ttytype file is set up to recognize vt100s, this should work.
Note this does not work on all machines. These methods were useless on
a motorola, for example
find
find (path name) -name (file name) -print
wildcards at the beginning of a find names must be preceded by a \. e.g.:
find / -name "\*bozo*" -print
finds all files with the letters bozo in them. Some systems require the
quotes as well.
ftp
Make sure the line setting is binary. Zipped files will not transfer
correctly if this is not set.
gdb (and dbx)
To examine a core file:
gdb <executable file name> <core file name>
The core file name is usually "core".
To examine an array:
p *arrayName@number_of_bytes_you_want_to_see
imake
The new way of handling compiling and linking programs is with a utility
called imake. It makes programs easier to move around from machine to
machine. To use it:
- Read the imake, make and xmkmf man pages. Also any README files
that came with the program you're trying to build. If you're going
to be getting into some serious program development, the emacs
info page on make is a must read.
- Back up everything! Source, Makefile, imakefile, etc.
- imake
- If imake doesn't work, try xmkmf
- If it *still* doesn't work, go back to step 0.
kermit (quick check of file integrity)
This is true for any other data transfer protocol as well, such as ftp.
Check the size of the files that you have transfered to the target system.
If they are not the same size, something went wrong.
login
To disable the annoying wait after an unsuccessful login, edit the file
/etc/login.defs. Change the parameter FAIL_DELAY from whatever it's set
to to 0. You'll have to be root to do this.
link (ln)
to create a symbolic link:
ln -s <existing file or directory> <Linked file or directory$gt;
e.g.:
ln -s OldFile NewLink
This creates a symbolic link name NewLink that points to OldFile.
When you access NewLink, Unix actually accesses OldFile.
Links are mainly used to save disk space, allowing yu to have the same
file in several different places without actually having maintain
multiple copies of the file.
less
Less can't display ANSI color escape sequences like most of the other Unix
text output utilities can. It instead tries to print them with ugly
results. On other unicies, the work around is to use the pg function, but
it's not avalible on Linux (yet).
Linux
To regain text that has scrolled off of the screen, try shift-PageUp
and/or shift-PageDown. This will work on a given console until you shift
to another one. When you shift back, however, you will find that the
scrolled text has been lost.
To change from virtual console to virtual console, use left alt (only the
left alt key works on my machine) FX where FX is one of the function keys
F1 thru F6. F7 will be your X window, and isn't set up for you to log
into it, but see the note below.
When you are in X, you can move back to the text consoles by simultaneously
typing the control and alt keys, and then the function key of the virtual
console you want to be in.
To add more virtual consoles edit your /etc/ inittab file and add a line to
the getty configuration section. I added this line to inittab and it
allowed me to add another virtual console:
c7:456:respawn:/sbin/agetty 38400 tty7
This let me log into F7, but not as root. To log in as root, I added this
line to the /etc/securetty file:
tty7
I did not add further consoles, as 7 is the canonical number for the
maximum number of things you want to juggle at one time, and each virtual
console takes up precious RAM even if it is dormant.
When your screen gives weird output for lower case letters, try this:
echo "^V^[c"
(that's E C H O space control-V escape C return) to fix it.
mail
To send a message with a subject:
mail -s "This is the subject" recipient@computer.full.ip.address < message
To forward your mail:
Create a file in your root directory called .forward. This file
should contain the address of the machine that you want to send the
mail to:
e.g. My .forward file reads:
Thomas.V.Bryant.1@gsfc.nasa.gov
make
The make utility *requires* that commands (as listed under a
target:dependency line) begin with a tab (ASCII 09).
If your emacs tab stops are set to under 8, emacs will insert spaces
(ASCII 32), and not a tab. This will stop make dead in its tracks.
You'll have to reset your tabs to edit a makefile.
If you break up the lines in your make file (a good idea: readability
is king!) don't put anything after your backslash (line continuation
symbol) or make will throw up on it:
LIBS = Lmylib Lyourlib ... \
^
|
|
No spaces or tabs or anything after here!!!
modem
When you install linux, your serial ports will not be configured. You have
to enable the call to /etc/rc.d/rc.serial in /etc/rc/rc.S:
# Run serial port setup script:
# (CAREFUL! This can make some systems hang if the rc.serial script isn't
# set up correctly. If this happens, you may have to edit the file from a
# boot disk)
#
# You need to enable this line (remove the # comment symbol):
. /etc/rc.d/rc.serial
# for your modem to work.
Networking
Installation (for Author's PPP link -- a *very* brief reminder list):
Load the networking module in the slakware file.
Create or copy the /etc/hosts file.
Create or copy the /etc/resolve.conf.
Edit /etc/rc.d/rc.serial.
Run time problems:
Try the ifconfig and netstat commands to find out what your current
network configuration is.
Use the ping command to check you connections.
Make sure that your linux kernel has drivers both for your network
card and ethernet. Networking will not work without them.
nroff
Many text files are quasi-readable, and filled with control characters.
If the file turns out to be an nroff man page, you can read it with the
command:
groff -Tascii -man file.name | less
Often a variation of this command is necessary. See the man pages for
groff and grog. Grog tries to look at the file for you and suggest a
command. This is one that repays a lot of fiddling. Back up the original
file, and groff away. Usually you'll get it. Remember also that
postscript files (usually denoted by a .ps suffix) are read with the
ghostscript command from X.
qsort
Here's a wierd one. The qsort function has a hard time calling it's
comparison function from a C file compiled with gcc. It works fine if gcc
thinks it's compiling a C++ file. Here's a pixel value sort I did,
heavily edited:
int pixCmp(pixel*, pixel*); // Return -1, 0, or 1. For the qsort call.
...
qsort(data, BigNumber, sizeof(pixel), pixCmp);
...
int pixCmp(pixel* a,
pixel* b)
{
if (a->clr > b->clr) return 1;
else if (a->clr < b->clr) return -1;
else return 0;
}
If the file is named pixels.c, it produces the following gcc error:
pixels.c: In function `readData':
pixels.c:164: warning: passing arg 4 of `qsort' from incompatible
pointer type
If the file is named pixels.C, it produces no errors:
PPP
Installing PPP to work with Linux can be done, but it is not trivial.
I'll describe the steps that worked for me, so that you might get a
variation on them to work for you.
Don't expect it to work perfectly the first time. You'll have to futz
with it, unless you are very lucky.
PPP must first be installed in your kernel. To check if it is there:
dmesg | grep -i ppp
You should get something that looks like this:
PPP: version 0.2.7 (4 channels) NEW_TTY_DRIVERS OPTIMIZE_FLAGS
PPP line discipline registered.
If you don't, you'll have to recompile your kernel, or get a copy of a
kernel that has ppp on it from the net. Instructions for doing this are
found in the file /usr/doc/ppp/README.linux.gz. This is where it is in my
Slackware release, yours will probably be similar. You need to read this
file now. Before you go any further. Otherwise, what follows will read
like gibberish.
Read the Readme? Good. Here's how my pppd/chat command looks:
/usr/sbin/pppd connect '/usr/sbin/chat "" ATDT7035551212 CONNECT "" ogin:\
tbryant word: secret_password' /dev/modem 38400 -detach crtscts modem \
defaultroute noipdefault
Fill in your appropriate telephone number, user ID and password.
Run the script from your root directory,unless you have given pppd suid
privileges (recommended).
When I am running the script, I do so from an X windows term, so I can
start netscape (or whatever X application I want) easily.
Once I've established the connection, then I can run netscape, ftp, or
telent to other internet connected machines.
My ISP (Internet Service Provider) assigns me a different IP address each
time I log on. This IP address can be found with ifconfig, or from the
/var/log/messages file.
The last few lines have what you need:
Aug 28 20:01:23 3C273 pppd[168]: local IP address 205.252.11.62
To log off, the PPP-HOWTO.gz document has the following logoff script:
#!/bin/sh
DEVICE=ppp0
#
# If the ppp0 pid file is present then the program is running. Stop it.
if [ -r /var/run/$DEVICE.pid ]; then
kill -INT `cat /var/run/$DEVICE.pid`
#
# If the kill did not work then there is no process running for this
# pid. It may also mean that the lock file will be left. You may wish
# to delete the lock file at the same time.
if [ ! "$?" = "0" ]; then
rm -f /var/run/$DEVICE.pid
echo "ERROR: Removed stale pid file"
exit 1
fi
#
# Success. Let pppd clean up its own junk.
echo "PPP link to $DEVICE terminated."
exit 0
fi
#
# The PPP process is not running for ppp0
echo "ERROR: PPP link is not active on $DEVICE"
exit 1
Additional hints not in the README.linux file:
All exchanges between you and you host computer will be logged in the
/var/log/messages file. Deducing what's going wrong is much easier if
you just look at the end of this file:
tail /var/log/messages
Keep trying, don't be afraid to futz around. If you're well backed up
(you *ARE*, aren't you?) you won't hurt any of you hardware, or
permanently damage any software (even this is very unlikely).
Good Luck!
rm
When a file absolutely refuses to go away, try surrounding its name
with quotes. This might kill it. I needed to remove a file called
#filename#. Here's how I fared.
rm #filename# Refused to work.
rm "#filename#" Worked.
rm '#filename#' Worked.
rm \#filename# Worked.
The top command worked on the older versions of Linux and SGI's IRIX.
This is probably a Posix compatibility problem that caused the more
recent versions of Linux to stop working.
Setup
The setup script will not run unless you are in /usr/lib/setup, and
running as root. Be careful. Back up everything before you start playing
around with this. Don't be afraid to play, however, as you can always
improve on the defaults Linux comes with.
swapon
To set up a swap file, (needed for installation)
- Start you new Linux box with the boot and root disks.
- make a partition (The rule of thumb is 1 - 2 times the size of
the RAM on your machine.) using fdisk. Be sure and set the
data type to Linux swap.
- Format the partition: mkswap -c </dev/partitionName>
- Enable swapping in /etc/rc.d/rc.S: /sbin/swapon -a
tar
To make a tar file:
tar -cf tarfilename filename (or directory. Directory is recursive)
This creates the file.
tar -rf tarfilename filename (or directory. Directory is recursive)
This appends to an existing file.
To extract a tar file:
Get into the directory where you want to have the files.
tar -xf (Complete filespec of the tar file to be extracted.)
test
*NEVER* *NEVER* *NEVER* name an executable test. This is a very easy,
logical thing to do. When you try and run it, the shell will invoke it's
test utility, find nothing there, and exit silently, leaving you very
puzzled.
Time
To set the system clock (CMOS) from Linux:
Set the system time from the CMOS clock, adjusting the time to correct for
systematic error, and writ- ting it back into the CMOS clock.
This option uses the file /etc/adjtime to determine how the clock changes.
It contains three numbers: The first number is the correction in seconds
per day (for example, if your clock runs 5 seconds fast each day, the
first number should read -5.0).
The second number tells when clock was last used, in seconds since
1/1/1970.
The third number is the remaining part of a second that was left over
after the last adjustment.
The following instructions are from the source code:
- create a file /etc/adjtime containing as the
first and only line: '0.0 0 0.0'
- run clock -au or clock -a, depending on whether your CMOS is
in Universal or Local Time. This updates the second number.
- set your system time using the date command. mmddhhmm[yy][.ss]
- update your CMOS time using clock -wu (for UT) or clock -w.
- replace the first number in /etc/adjtime by your correction.
- put the command clock -au or clock -a in your /etc/rc.local,
or let cron(8) start it regularly.
useradd
When a user is added, you have to make sure that the user owns, or at least
has read, write, and execute privileges on his/her home directory. If you
neglect this step, the new user will be unable to function properly, and
perhaps will not be able to log on!
The /usr/bin directory must have its privileges set to 755 in order for
users to be able to execute the UNIX commands contained therein.
Virtual Terminals:
To change from terminal to terminal:
Left Alt + fn
(n is the terminal number, from 1 - 6 and f is a function key.)
To return to virtual terminal text mode from X:
Left Alt + Control + fn
n is again the number of the terminal you want.
To see text that has scrolled off of the screen:
Shift + Page up or Page down.
Moves you up and down by half a screen each time.
To see task information:
+ Scroll Lock
To see memory information:
Shift + Scroll Lock
X:
There are few short X tips. You need to read much of the documentation
that is out there, and but the O'Rielly series in X and Motif if you
intend to do serious developemt. It's an extrodinary, platform
independent, system that solves some very difficult problems with
accessing system resources in a uniform way. It's also very complex, with
all sorts of redundant functions and kludges. Good Luck.
If you're going to just start getting into building user interfaces, I
suggest that you bypass X entirely, and concentrate on Java. Of course,
Java for Unix platforms is based on X, but you shouldn't have to worry
about that.
Copyright © 1998, Tom Bryant
Published in Issue 29 of Linux Gazette, June 1998
"Linux Gazette...making Linux just a little more fun!"
A Linux Journal Preview:
This article will appear in the August issue of Linux Journal.
UniForum '98 Report
I am writing this article as I fly back from the UniForum Association
Spring '98 Conference. This was the first ever East Coast conference
held by UniForum in its 17 year history. It was held in Ocean City,
Maryland--a beautiful town by the Atlantic Ocean.
UniForum is an advocacy
organization that promotes the use of Open Computing solutions--or, to
put it in succinct terms--the use of UNIX and UNIX-like solutions.
UniForum and Usenix have tended to complement each other with UniForum
being the conference for suits and Usenix the conference for T-shirts.
The conference was a two and a half day event that looked light on paper.
Once there, I discovered there was too much to do in such a
short time. For the first two days, there were three tracks: New Open
Software Development Model and Linux, Network Computing and
Best of SCO Forum. All tracks included common Plenary and Keynote
sessions. On the third day there were two three-hour sessions: one presented by
the Open Group and the other by Linux International.
I attended all the Linux track sessions as well as the common sessions.
Monday's Plenary session was Eric Raymond's presentation of his paper The
Cathedral and the Bazaar which is credited with convincing Netscape to
take their Open Source stance.
If you haven't heard the talk or read the paper, it is available on our
Linux Resources page.
After Jon Hall introduced the Linux track, Frank Hecker, who is a systems
engineer at Netscape, gave a talk entitled The Why and the How that
filled in the background of Netscape's decision to embrace the Open
Source model.
For those of us who have been involved in what I call ``revolution from
below''--that is, attempting to sell Linux or Open Source to those in the trenches
and let it move up the corporate ladder--Frank had some interesting
things to say.
He said the engineers didn't believe Open Source could happen with
Netscape. So, Frank went to Marc Andreessen with the idea, and the rest is
history.
After Frank's talk, we got together for the keynote lunch where Ralph
Nader (UniForum Press Release) spoke on the Microsoft monopoly and how Linux could be a big player
in an alternate solution.
It was a treat to get to meet Ralph and to hear the
word Linux come out of his mouth just a few days after hearing Marc
Andreessen saying it.
I brought up how U.S. government procurements used to require a
POSIX-compliant operating system be made available with any system they
purchased, and Ralph and his staffers are going to look into why that
requirement was dropped.
I asked him to keep LJ up to date on any findings, but you might also
wish to check out his web site at http://www.essential.org/.
Two afternoon sessions were held in the Linux track.
The first was presented by Ron Workman of Cygnus Solutions, and the second
was presented by me. Covering mine is easy--I went through a series of
articles which have appeared in our Linux Means Business column,
illustrating how companies identified a problem, then used Linux to
address that problem.
Ron's talk addressed Open Source software from a different direction:
how a company can succeed in the business of supporting freely
available software. Cygnus was
founded in 1989 to provide commercial support for open Internet technologies
and has grown to 160 employees. The company has succeeded by offering
consulting and support on such products as the Free Software
Foundation's GNU C Compiler.
Monday evening was filled with good food and bad beer (Coors
Light?--lucky Linus wasn't there) at a beach party hosted by Red Hat
Software.
Like most parties at these conferences, the evening was filled with
meeting others and talking about computers, the UNIX market and telling
Microsoft jokes.
I found it a valuable time to get to know people better, for example, Morgan Von
Essen and Garry Paxinos of Metro Link, and to thank Alan Fedder and Kathy
Goetz of UniForum for organizing the conference.
Tuesday morning started with a Plenary by Eid Eid, President of Corel
Computer (see LJ, Issue 48). If I had to choose one person who provided
me with the most
new information, I would choose Eid. I did cheat a little however, as I also
talked to him extensively over lunch.
Eid's Plenary was a pleasant combination of future fantasy and a look at
what is available today. The fantasy part consisted of describing a day in
the life of Mr. Twenty O'One, illustrating what we should
expect in the near future (2001 isn't that far away) from our personal
communicator: voice- and e-mail access,
voice commands and an interface to the Corel NetWinder.
At the office, Mr. Twenty O'One will have a typical Intel-based PC
but most of his work will be done on his personal communicator and his
NetWinder. The NetWinder is much faster for doing common tasks
because, while it is a complete Linux system, common tasks (everything
from e-mail to video conferencing and replying to e-mail with a
voice message automatically appended to e-mail) are trivial to
access.
After this fictional introduction, Eid went on to cover the pieces which
actually exist today, including the NetWinder, video conferencing, XML and capable
portable systems.
He went on to say that we need to make all the interfaces and
standards open so any vendor can produce pieces which interoperate.
I expect some people were surprised when he said, ``Corel, Lotus and
others
will have no choice but to provide some source code for commercial
products in the near future.''
Eid also pointed out that Microsoft
controls over 50% of the money made on PC applications.
Eid was the Chief Technical Officer for Corel Corporation, makers
of CorelDraw and owner of Corel Computer before coming President of Corel
Computer.
He explained how Corel had been a Microsoft partner until Corel acquired
WordPerfect, then Microsoft started hiding technology from them.
As many of us have concluded in the past, Eid believes you cannot
successfully fight Microsoft, but went on to point out what you can do.
He sees the network computer as the new wave, being less costly and more
maintainable.
The network computer opens up a new market and, done right, it can become a
market as large as today's personal computer market.
The morning session in the Linux Track included a presentation by Don
Rosenberg of Stromian Technologies on making money with Open Source as
an OEM/VAR.
Differing from Ron Workman's presentation of the previous day, Don's
presentation was a mini-tutorial on how to get into a market and how to
make the right distribution choices along the way.
Next, Morgan Von Essen, President of Metro Link, with the help of Garry
Paxinos, Vice President, presented a talk on Metro Link's cooperative
work with the XFree86 community--another model of a commercial
enterprise working with the free software community.
In this case, they developed technology needed for their
commercial customers and then gave that technology back to the
XFree86 community. Doing this makes it easier for Metro Link to continue
development, because their work becomes standard in new XFree86 releases.
Tuesday's keynote lunch was presented by Janpieter Scheerer who was
President of Sunsoft and has now moved to head the storage division of Sun.
He talked about WebTone and made some very interesting points
demonstrating how the non-Microsoft community is growing faster than
the Microsoft community.
His pointed out that while MS Windows sales are growing at 13% a year,
companies like Cisco are growing at 30%, and that while there are over
100,000,000 MS/PC users, that number is a small minority of the six
billion people on the planet.
He also pointed out that every Quicken user who registers their product
is a UNIX user since the Quicken on-line registration server runs on
Sun systems.
Janpieter explained that today most ISVs will port their product to
either NT or Solaris. By
mentioning an old Dutch saying, ``the enemy of my enemy is my
friend,'' he clearly
sees Linux as an ally. By the same reasoning, we need to see Sun ports as
potential Linux ports of the future.
Janpieter, like Eid, pointed out that the network computer is in--all
we need is a $150 device to connect to the Internet.
He then went on to talk about two subjects: first
``OPEN-standardization''
and then Java.
This got a reaction from both Eric Raymond and Eid Eid, who both pointed out that
for Java to be the answer, its standard needs to be open.
There was no resolution, but I am sure we were heard.
The afternoon Linux track brought Bob Young discussing the size of the
Linux market or, more accurately, explaining how hard it is to come up
with an accurate estimate.
Bob also announced the availability of the Extreme Linux CD which
includes all the Beowulf RPMs for those of you who want to build your
own supercomputer.
Jon Hall of Linux International closed the track with some general
comments and preparation work for the workshop the following morning.
On Wednesday the Linux track attendees changed their plans and
attended the first hour of a presentation entitled What Exciting
Technology is Emerging? by The Open Group, the organization that owns
the UNIX brand and standards.
In this presentation, the Open Group announced the UNIX'98 standard.
Historically, vendors such as Digital, Hewlett-Packard and Sun have paid
a lot of money to use the UNIX brand.
This money goes to support The Open Group's work on the standards and
enforcement of the trademark.
While it would be great for Linux or a Linux distribution to be UNIX
branded, the cost is prohibitive.
The Open Group has now
recognized the advantage of getting the Linux community on board.
While Sun and others anchor the high end of the Open Systems community,
having an entry-level system compatible with the standard would be a plus.
This is not yet a done deal. While the use of the
UNIX trademark is limited to those who have paid the fees, the
opportunity will be present for a system to be conformant with the standard.
Stay tuned, this could be the in necessary to tighten the bond
between Linux and the rest of the UNIX community.
For more information on the UNIX'98 standard, see the web page
http://www.UNIX-systems.org/.
The melding of minds with regard to UNIX standards, Open Computing and Open
Source software needs a venue and UniForum has elected to be that venue.
Here's what Alan Fedder (UniForum Press Release), President of UniForum had to say about it:
UniForum Association is the only forum for open
discussion and open debate about open computing.
Where else could Eric Raymond and Mike Lambert [of The Open Group]
debate each other, listen to each other, and have a
better understanding of each other's position? Where
else could you hear Ralph Nader, Eid Eid, Janpieter
Scheerer, Eric Raymond--all quoting Eric Raymond?
Momentous things happened at the UniForum Spring
Conference in Ocean City--and I honestly believe
that five years from now, 5,000 people will be telling
each other they were there when UNIX was saved.
In conclusion, I found attending the conference to be truly worthwhile
and look forward to going again next year.
Copyright © 1998, Phil Hughes
Published in Issue 29 of Linux Gazette, June 1998
"Linux Gazette...making Linux just a little more fun!"
Using rdist for Backups
In Linux Gazette Issue number 24 Gerd
Bavendiek described his script which he calls "mirror." In this
script he makes use of the utility 'rdist' which is widely available on
Unix systems. In my article I shall explain how I use 'rdist' which
I hope will give the beginning Linux user a background to Gerd's article
and show how useful 'rdist' is to those with multiple computers (which
should be every Linux user nowadays!)
In the UK today you can get a complete 486DX66 system including monitor
for a hundred pounds, which has got to be a bargain and ideal as a backup
system for your "main" computer. Even if you feel its hard disk is too
small (typically they have them in the 200-300meg range) today you can
get a 2gig hard disk for under one hundred pounds or an 850meg one for
sixty pounds. So for no more than a couple of a hundred pounds you not
only have a backup device but a working computer you can use in emergency
in the event of the failure of your "main" machine. I have two 486DX66s,
both other peoples' discards which cost me nothing apart from extra RAM
and a bigger hard disk for the "main" machine (and a modem of course -
though now I have a couple of spare V32bis other people have junked,
isn't progress wonderful). One has 40meg of RAM and is my "main" computer
running Slackware 3.3. The other has 8meg of RAM and Slackware 3.3 again.
The "backup" has a half gig hard disk given to me because it makes an
unpleasant whine during operation. In spite of the noise, the disk
works fine so is good for backup space. A couple of discarded network
cards from a "parts bin" and a look at the NET-3-HOWTO
(you can find this in the directory '/usr/doc/faq/howto' in Slackware 3.3)
gets the two computers talking to each other. Other alternatives are PLIP
or a null modem cable, but network cards are easy to come by nowadays.
(Note: network cards with RJ45 interfaces can connect two computers
together if you make a crossover cable, it works for me.)
Once the computers are talking you can use ftp or even Samba to
transfer files, as well as mounting various drives and partitions
by NFS. All good clean fun. But the ideal way to maintain a "mirror"
of your home directories so you don't lose any precious datafiles is
to use 'rdist'. (Note: the following describes a Slackware 3.3 setup
but the procedure should give the rest of you a start.) Firstly you
must amend the file 'hosts.equiv' on the "backup" machine (i.e. the
one you are going to back-up the files to) to allow users to 'rlogin'
(see the man page for 'rlogin') to the "backup" computer from the "main"
computer without having to supply a password. 'hosts.equiv' is found in
'/etc' (Slackware), the stock 'hosts.equiv' has one entry, 'localhost'.
Simply add the relevant name or IP address for your "main" computer (go
back and read the NET-3-HOWTO, you know you have to)
on a new line. If you have accounts (same user name) on both machines,
you are now able to 'rlogin' to the "backup" from the "main" with the
command 'rlogin <other_computer_name>' and it should not
demand a password (unless you are 'root', but you don't want to mess
around letting 'root' rlogin without a password, do you?).
Now you're cooking with gas. Make a file called 'distfile' in your
home directory on your "main" computer. Here's one I made earlier--
HOSTS = ( johnny@pod )
FILES = ( ~/ )
EXCEPT = ( ~/.netscape ~/\(PROG\) ~/StarOffice-3.1 ~/.trash ~/.bash_history )
${FILES} -> ${HOSTS}
install -oremove,chknfs,younger ;
except ${EXCEPT} ;
Now's the time for you to consult 'man rdist' to see what all this means.
The first three lines set variables - it is possible to give 'rdist'
command line switches to modify these, so it could be helpful when you
get more adventurous. The last three lines are commands for 'rdist'.
The 'install' command copies/deletes files/directories as specified.
The 'except' command omits the specified files/directories from
processing. (If you specify a directory it means that directory's
files and subdirectories and files.) The '->' line tells it what to
where. Note the 'host' is the "backup" computer and given of the form
'user@domain'. This should be an account you can 'rlogin' to without
needing a password (modify 'hosts.equiv' see above). If you look at
the above example, it says,
"Copy the entire home directory to "pod," excepting the Netscape cache
directory, the trash directory, the StarOffice stuff and the .bash_history
file."
The switches to 'install' say,
"Remove any files on the backup that aren't on the main machine,
don't follow through NFS links, and don't update files on the backup
machine that are younger than the equivalent on the main machine."
Note how 'remove'and 'younger' interact: 'remove'
will remove any orphan files, so 'younger' won't keep brand new files
on the backup that haven't been made on the main machine - decide what
you want! In the case of a backup to an account you don't use then
'younger' isn't really necessary. If it's an account you do use, then
don't use 'remove' but do use 'younger'.
A perusal of the 'rdist' man page should make this all clear. Having made
the 'distfile,' all you have to do to synchronize the files on your
two machines is type 'rdist' at the prompt on the "main" machine and
it will go ahead and do it all for you and tell you about it. 'rdist'
will create directories as needed, preserve permissions, ownerships etc.,
will only change files that don't match (you can alter the criteria it
uses to decide this, see the 'man' page). It is excellent! Run 'rdist'
regularly and you need never "lose" your data-files. Even better if
you back-up over the Internet to a remote location.
Now you can go back to Gerd's
article and see how he uses his script to keep his laptop and desktop
in synch. A study of the 'rdist' man page will make evident that 'rdist' has
great power and flexibility for the adventurous. There really is no
excuse for not backing up your work!
John Pate
Last modified: Sat May 2 12:25:18 BST 1998
Copyright © 1998, John Pate
Published in Issue 29 of Linux Gazette, June 1998
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
Tom Bryant
Tom has been working with computers since 1978.
Since then, I wrote my thesis (on emission lines in planetary nebulae)
on an Apple II, wrote the telemetry processing program with which NASA deduced
some of the early problems with the space telescope (its direct descendant is
still in use today), and lately a program that fixes a serious telemetry
formatting error on the EOS AM-1 satellite. I've written programs that
display tesseracts, simulate a star cluster with accurate stellar motions,
implement a new language (related to forth), and play the piano!
My interests include (in alphabetical order) 35mm photography, the
American Civil war, Astronomy, Beethoven, Chopin, Classical piano,
Cryptography, Explorer post 1275, Fixing old cars, History, Mathematics,
Rachmaninov, Science, Single Malt Scotch, Sports cars, Telescope making...
My wife and I have 2 kids, 2 cars, 2 birds and 1 18 year old cat.
Jim Dennis
Jim 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. His wife,
Heather Stern, is now doing the HTML for his column.
Michael Hamilton
Michael has been working as a freelance Unix C/C++ developer
since 1989. More recently he's been working on web applications and
Unix server administration. Michael tripped over one of Linus's
postings back at the beginning of 1992 and has been hooked ever
since.
Phil Hughes
Phil Hughes is the publisher of Linux Journal, and thereby Linux
Gazette. He dreams of permanently telecommuting from his home on the
Pacific coast of the Olympic Peninsula.
As an employer, he is "Vicious, Evil,
Mean, & Nasty, but kind of mellow" as a boss should be.
Andy Kahn
Andy works at Digital Equipment Corporation doing
Digital Unix filesystems kernel development.
He thinks he's just hacking away at more and more C code,
and in his copious spare time, he hacks on lots of other
things, including all the trees in his neighborhood.
Feel free to send him
email.
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.
David Nelson
David manages scientific research at the U.S. Department of
Energy. Before that he earned his living as a theoretical plasma
physicist. He started programming on the IBM 650 using absolute machine
language and later graduated to CDC, DEC and Cray machines for his
research. But Linux is the most fun. He and his wife, Kathy, live
near Washington DC; they enjoy tennis, skiing, sailing, music, theater
and good food.
John Pate
John works part-time at Café
Cyberia Edinburgh and is looking for a full-time job in Unix System
Administration. John has a first degree in Psychology and has
been playing on the Internet since he first discovered it in the
late eighties. Having worked for a while programming for Windows
3.1x he decided Linux was the way forward. He can be contacted at johnny@dvc.org.uk and his homepage
is at http://www.dvc.org.uk/johnny
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. And a special thanks to Heather Stern for the great job
she is doing on htmlizing "The Answer Guy". It looks good and she's saving
me a lot of work. :-)
My wonderful father-in-law, Ralph Richardson, has moved to Seattle from
Southern California. He's been here almost 2 weeks now and it's been fun
helping him get settled in and seeing him on a much more frequent basis. I
know we'll get used to him being here all the time, but right now getting
to see so much of him feels like vacation. And I can use as much vacation
as I can get! :-)
Have fun!
Marjorie L. Richardson
Editor, Linux Gazette, gazette@ssc.com
Linux Gazette Issue 29, June 1998,
http://www.linuxgazette.com
This page written and maintained by the Editor of Linux Gazette,
gazette@ssc.com
Date: Wed, 13 May 1998 13:39:17 -0700
More 2¢ Tips!
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