Are there any Cobal compilers that will run under Linux, I have a
serious need to move some code to the Linux platform if there is
something available. Thanks.
I have a Packard Bell Pack-Mate 4990CD, which has a soundcard apparently
called a "SOUND16A" (the documentation doesn't make it clear whether PB or
Aztech made it, or if it was a joint production). It is a 16 bit sound
card, which I can use under Windows 95 as such. However, in Linux, the
best I can do is 8 bit sound (via Sound Blaster Pro 2.0 emulation). The
card claims to support MSS, but nowhere in the documentation or setup
program does it specify which IRQ this runs at, although it does tell what
port. I have contacted Packard Bell's tech support, but they say they only
support Windows software for free, and that if I wanted to talk about Linux
or some such operating system, I would need to get "special support" which
would cost a ridiculously high number.
As a struggling college student, I don't have much money to spend on the
computer (it is actually my family's that I scratched up enough space to
install Linux on), so I can't get a new sound card, and I am not even sure
if the commercial sound drivers support this particular sound card.
I'm probably spoiled by Windows, but it's not asking too much for 16 bit
sound so I can listen to 44KHz samples in stereo (I'm quite a MOD fan),
listen to MP2's or MP3's, etc...
I'm not much of a coder, so I can't go about writing my own drivers. If
anyone knows of how to set up this sound card for full 161 bit sound,
please inform me. Or, if you know of any 8 bit .MP? players, that would
work too =)
I would like to install Linux on a Sun 386i machine with 16 meg of ram, 2
350 meg scsii drives color video adapter and a tape drive, and Network
support. When I try to install using a boot disk, I get the following message.
This occurs with any boot disk except for Sun. Is there a way I can get
Linux to install to this system? Any suggestions would be greatly
appreciated. If you can not help me, Please redirect this message to
someone who could. I don't know where to get this type of information. I
received these machines for free and would like to put them to use using
Linux.
Thank you
Albert F. Race
Is there a chance to correctly configure a Matrox Mystique with 4MB RAM
under X or I must throw away it ?
Hello,
Please help-me to interface my Color Page CS desktop scanner to Linux.
Now, I can scan only from Windows (Argh!!) and it would be fine to have
The Gimp accessing my scanned material. I can program in C and Tcl/tk, if
I at least have the information on its SCSI card, and the scanner itself.
Any information you may have is precious to me. When I have this job done,
of course, I'll be happy to publish my adventures in the Gazette.
My screen maybe 800x600 but my virtual screen is set at something like 1600x1200. How do I change this?
Note:
Sir,
I am a 35 from Sweden using at present *2 90 Pentium /NT4 and Slakeware
1.2.13 and Red Hat 3.0 (and DOS 6.22 !) all on the same machine. (paranoid !)
I am interested in knowing how to take advantage of the *2 cpu's on a Linux
based machine.
Any thing regarding *2 + processing is of interest to me, as i use the NT4 as
a server and would like to try using Linux instead.
many thanks in advance
I have a mess of family photographs and possibly 35mm slides that I
want to preserve. One idea I'm considering is scanning these and putting
them on CDs. So I have a few questions.
When I use a dos ftp(in ascii mode) program to download a Linux Script,
because it is not running yet, the script fails to work when installed.
This is because a ^M is appended to every line, take them out and it works.
I'm a new user to Linux and the problem still XFree86! So then I tried
to know want can I do to Linux community. In Issue #16, you said
that the problem is not video card and is Monitor balancing. So why
Windows 95 can have all these preset on monitor and Linux don't have?
Why we can't use the stuff in the Microsoft Lib to transfer it into the
database of XF86Setup or something like that. Cause that's real that
the dotclock and all this is very scrambled! Why not just resolution
and Virtual Refresh, that's all we need to know, the program could do
the rest! We don't have to know what horizontal frequency and dotclock
it is!
Hi,
If you happen to have time on your end please be so kind as to answer a
few questions for a newbie!
Well , here is the situation and I need to get some serious advice
from people like you. I have been reading the newsgroups and HOWTO's .
They have been quite informative and ,increasingly so, as I continue .
Now , thank GOD I got my Linux (RED HAT 4.1) box set up and running on
my slave drive with Win95 on the Master. It detected my CDROM and I also
configured my Xwindows (X11R6) .
Hello!
Please can you point me to some direction were I can find a user-level
driver for the HP ScanJet 5p? There exist the HPSCANPBM driver which
works in part, but does not support the -width and -height options
for the ScanJet 5p. I guess it was written for a ScanJet 4c or something like that.
BTW: The homepage of HP does not give much support for Linux users. They do not publish the ESCAPE sequences of the scanners.
Before more users spend many hours downloading the 50 megabyte (!)
WordPerfect for Linux, you may want to note that the beta download lets
you get a demo version that times out after just 15 days. They seem to
have demo versions of WordPerfect 6 available, so it is not that big a
deal.
However, I would like to see a comparison of WordPerfect for Linux,
StarOffice's word processor and the what is planned for GNU WP.
Hello,
I'd like to download the past issues of LG (having enjoyed LJ now since
last fall), but I don't think I could even get an 11 meg file downloaded
over my 14.4 modem within the 1 hour that I have before my local Internet
connection (the Greater Detroit Free Net) times out on me. Is there any
way to download the past issues in smaller "chunks"?
(Hmmm, that is a problem. No, I don't save the individual tar files of
previous issues separately. There is, of course, TWDT,
option for each issue which gives you the issue as one great big
file. Not as nice as the normal multi-file format but very popular so must
work for some. --Editor)
Date: Wed, 04 Jun 1997 22:52:36 -0700
From: James Zubb jimz_@ecom.net
Subject: ActiveX for Linux
Hi,
I read the ActiveX for Linux question in the Answer Guy's article, I did a
little looking and came up with a web site:
http://www.sagus.com/Prod-i~1/Net-comp/dcom/index.htm
I don't know if this is actually the ActiveX port for Linux or not, I
didn't feel like trying to figure it out, but there is a Beta for Linux
there. Beats me what it does or how it does it...
--
Jim Zubb
Date: Fri, 6 Jun 1997 19:01:40 +0100 (BST)
From: Adrian Bridgett apb25@cam.ac.uk
Subject: Re: X Color Depth
(In response to the message by Roland Smith)
Normally 8-bit displays use 256 colours chosen from 2^24 (16,777,216), and
15/16/24/32 bits displays just use a fixed number of colours spread
"evenly" throughout the colour spectrum.
16-bit displays use 5 bits for red, 5 bits for blue and 6 bits for green,
however the 65536 colours cannot be changed and so the overall
"resolution" of colour is lower than 256 bit displays. For instance you
can only have 2^5 different shades of green, rather than 2^8.
Adrian
Date:Thu June 12 08:39:19 PDT 1997
Timothy Gray timgray@lambdanet.com
Subject: CNE Certification for Linux?
Oh, no not a certification suggestion......
Linux was developed as a better and free version of UNIX.
Now someone wants to make a CNE for Linux? As a successful Linux Network
Administrator (and Business owner that proudly states no Microsoft here!)
I am appalled at charging ten's of thousands of dollars to get a piece of paper
that states I can do my job. As an Internet service provider and an avid
Linux, Freeware, and Free Software Foundation supporter I hire my network
administrators and Engineers( We call them System Administrators ) based on
their abilities and trainability. A CNE paper does not nor will ever impress
me. Even suggesting such an idea toward Linux is appalling. Let's keep our
last bastion of freedom from the clutches of cooperate greed! If we must
have a Linux CNE make it 100% free and available to everyone on the planet.
Thank you,
Timothy Gray
Published in Linux Gazette Issue 19, July 1997
![[ TABLE OF
CONTENTS ]](../gx/indexnew.gif)
![[ FRONT
PAGE ]](../gx/homenew.gif)
This page written and maintained by the Editor of Linux Gazette,
gazette@ssc.com
Copyright © 1997 Specialized Systems Consultants, Inc.
"Linux Gazette...making Linux just a little more fun!
"
Send Linux Tips and Tricks to
gazette@ssc.com
Contents:
Rude Getty
Date: Mon, 23 June 1997 21:12:23
From: Heather Stern star@starshine.org
I have a fairly important UNIX box at work, and I have come across a good
trick to keep around.
Set one of your console getty's to a nice value of very rude, -17 or worse.
That way if a disaster comes up and you have to use the console, it won't
take forever to respond to you (because of whatever went wrong).
Keeping Track of File Size
Date:Mon 16 June 1997 13:34:24
From: Volker Hilsenstein vhilsens@aixterm1.urz.uni-heidelberg.de
Hello everyone,
I just read Bob Grabau's 2C-tip for keeping track of the size of
file. Since it is a bit inconvenient to type all these lines
each time you download something I wrote this little script:
#!/bin/bash
# This script monitors the size of the files given
# on the command line.
while :
do
clear
for i in $@; do
echo File $i has the size `ls -l $i | tr -s " " | cut -f 5 -d " "` bytes;
done
sleep 1
done
Bye ... Volker
Reply to "What Packages do I Need?"
Date: Tue 24 June 1997 11:15:56
From: Michael Hammel, mjhammel@long.emass.com
You asked about what packages you could get rid of and mentioned that you
had AcceleratedX and that because of this you "can get rid of a lot off the
X stuff". Well, thats not really true. AcceleratedX provides the X
server, but you still need to hang onto the X applications
(/usr/X11R6/bin/*) and the libraries and include files (/usr/X11R6/lib and
/usr/X11R6/include) if you wish to compile X applications or run X binaries
that require shared libraries.
Keep in mind that X is actually made up of three distinct parts: the
clients (the X programs you run like XEmacs or Netscape or xterm), the
server (the display driver that talks to your video adapter), and the
development tools (the libs, header files, imake, etc). General users
(non-developers) can forego installation of the development tools but need
to make sure to install the runtime libraries. Each Linux distribution
packages these differently, so just be careful about which ones you remove.
One caveat: I used to work for Xi Graphics, but that was over a year and a
half ago. Although I keep in touch with them, I haven't really looked at
the product line lately. Its possible they ship the full X distributions
now, but I kind of doubt it. If they are shipping the full X distributions
(clients, server, development tools) then disregard what I've said.
Hope this helps.
--
Michael J. Hammel
Sound Card Support
Date: Mon 24 June 1997: 11:16:34
From: Michael Hammel, mjhammel@long.emass.com
With regards to your question in the LG about support for the MAD16 Pro from
Shuttle Sound System under Linux, you might consider the OSS/Linux product
from 4Front-Techologies. The sound drivers they supply support a rather
wide range of adapters. The web paget http://www.4front-tech.com/osshw.html
gives a list of what is and isn't supported. The Shuttle Sound System 48 is
listed as being supported as well as generic support for the OPTi 82C929
chipset (which you listed as the chipset on this adapter).
This is commercial software but its only $20. I've been thinking of
getting it myself. I have used its free predecessor, known at times as
OSS/Lite or OSS/Free, and found it rather easy to use. I just haven't
gotten around to ordering (mostly cuz I never seem to have time for doing
installation or any other kind of admin work). I will eventually.
4Front's web site is at http://www.4front-tech.com.
Hope this helps.
--
Michael J. Hammel
InstallNTeX is Dangerous
Date: Fri 06 June 1997 12:31:14
From: Frank Langbein langbein@mathematik.uni-stuttgart.de
Dear James:
On Fri, 6 Jun 1997, James wrote:
You have still
make_dir " LOG" "$VARDIR/log" $DOU 1777
make_dir " TMP-FONTS" "$VARDIR/fonts" $DOU 1777
If I hadn't (now) commented-out your
(cd "$2"; $RM -rf *)
then both my /var/log/* and /var/fonts/* files and directories would have
been deleted!
Actually VARDIR should also be a directory reserved for NTeX only (something
like /var/lib/texmf). Deleting VARDIR/log is not really necessary unless
someone has some MakeTeX* logs in there which are not user writable. Any pk
or tfm files from older or non-NTeX installations could cause trouble later.
Sometimes the font metrics change and if there are some old metrics used with
a new bitmap or similar the resulting document might look rather strange.
Further log and fonts have to be world writable (there are ways to prevent
this, but I haven't implemented a wrapper for the MakeTeX* scripts yet), so
placing them directly under /var is not really a good idea. I am aware that
the documentation of the installation procedure is minimal which makes it
especially hard to select the directories freely.
The real problem is that allowing to choose the directories freely. Selecting
the TDS or the Linux filesystem standard is rather save and at most any other
TeX files are deleted. The only real secure option would be to remove the free
choice and only offer the Linux filesystem standard, the one from web2c 7.0
which is also TDS conform and a TDS conform sturcutre in a special NTeX
directory. The free selection would not be accessible for a new user. I could
add some expert option which still allows to use a totally free selection.
Additional instead of deleting the directories they could be renamed.
There are plans for a new installation procedure, also supporting such things
as read only volumes/AFS, better support for multiple platform installation,
etc. This new release will not be available before I managed to implement all
the things which were planed for 2.0. But that also means that there will
probably be no new release this year as I have to concentrate on my studies.
Nevertheless I will add a warning to the free selection in InstallNTeX. That's
currently the only thing I can do without risking to add further bugs to
InstallNTeX. Considering that my holiday starts next week I can't do more this
month.
BTW, on another point, I had difficulty finding what directory was searched
for the packages to be installed. Only in the ntex-guide, seemingly buried,
is there:
This is caused by different ways to look for the package in NTeX-install, the
text version of InstallNTeX and the Tcl/Tk version of InstallNTeX. Therefore
you get some warnings even if NTeX-install would be able to install the
packages. The minimal documentation is one of the real big drawbacks of NTeX.
I'm currently working on a complete specification for the next release which
will turn into a real documentation.
Thanks for pointing out the problems with the free selection of that paths. So
far I concentrated on setting the installation paths to non-existing
directories.
Regards,
Frank
Reply to Dangerous InstallNTeX Letter
To: Frank Langbein, langbein@mathematik.uni-stuttgart.de
Date: Sat, 07 Jun 1997 10:11:06 -0600
From: James james@albion.glarp.com
Dear Frank:
The hidden application of the operation
rm -rf *
to the unpredictable and
unqualified input from a broad base of naive users is highly likely to
produce unexpected and undesired results for some of these users. This is
the kind or circumstance more usually associated with a "prank". If this is
_not_ your intent, then further modifications to the script "InstallNTeX"
are required.
The script functions at issue include: mk_dirchain() ($RM -f $P), make_dir()
($RM -rf * and $RM -f "$2"), make_tds_ln() ($RM -f "$3"), and link_file()
($RM -rf "$2"). The impact of the operations when using unexpected
parameters, from misspellings or misinterpretations, for instance, should be
considered.
You might simply replace these operations with an authorization dialog, or
you could create a dialog with several recovery options. (For the moment, I
have replaced them with `echo "<some <warning parm&gr;"'.)
James G. Feeney
Monitoring An FTP Download
Date: Tue, 10 Jun 1997 19:54:25 +1000 (EST)
From: Nathan Hand Nathan.Hand@anu.edu.au
I saw the recent script someone posted in the 2c column to monitor
an ftp download using the clear ; ls -l ; sleep trick. I'd just like
to point out there's A Better Way.
Some systems will have the "watch" command installed. This command
works pretty much like the script, except it uses curses and buffers
for lightning fast updates. You use it something like
watch -n 1 ls -l
And it prints out the current time, the file listing, and it does
the refreshes so fast that you don't see the ls -l redraws. I think
it looks a lot slicker, but otherwise it's the same as the script.
I don't know where the watch command comes from. I'm using a stock
standard Red Hat system (4.0) so hopefully people with similar setups
will also have a copy of this nifty little tool.
Programming Serial Ports
Date: Wed 18 June 1997 14:15:23
From: Tom Verbeure to_verbeure@mietec.be
Hello,
A few days ago, I had to communicate using the serial port of a Sun workstation.
A lot of information can be found here:
http://www.stokely.com/stokely/unix.serial.port.resources
and here:
http://www.easysw.com/~mike/serial
Reading chapters 3 and 4 of that last page, can do wonders. It took me about 30
minutes to communicate with the machine connected to the serial port. The code
should work on virtually any unix machine.
Hope this helps,
Tom Verbeure
Another Way of Grepping Files in a Directory Tree
Date: Thu 12 June 15:34:12
From: Danny Yarbrough danny@interactive.visa.com
That's a good tip. To work around the command line length limitation,
you can use xargs(1):
find . -name "\*.c" -print | xargs grep foo
this builds a command line containing "grep foo" (in this case), plus as
many arguments (one argument for each line of its standard input) as it
can to make the largest (but not too long) command line it can. It then
executes the command. It continues to build command lines and executing
them until it reaches the end of file on standard input.
(Internally, I suppose xargs doesn't build command lines, but an array
of arguments to pass to one of the exec*(2) family of system calls. The
concept, however is the same).
xargs has a number of other useful options for inserting arguments into
the middle of a command string, running a command once for each line of
input, echoing each execution, etc. Check out the man page for more.
Cheers!
Danny
More Grepping Files
Date: Mon 16 June 1997 08:45:56
From: Alec Clews Alec@tca.co.uk
grep foo `find . -name \*.c -print`
The only caveat here is that UNIX is configured to limit max chars in a
command line and the "find" command may generate a list of files too
huge for shell to digest when it tries to run the grep portion as a
command line. Typically this limit is 1024 chars per command line.
You can get around this with
find . -type f -name \*.c -exec grep foo {} /dev/null \;
Notes:
The -type f skips directories (and soft links, use -follow if
needed) that end with a c
The /dev/null is required to make grep display the name of the file
it's searching. grep only displays the file name *and* the search string
when there are multiple files to search, and /dev/null is a 0 length
file.
Regards,
Alec
Still More On Grepping Files
Date: Sat 14 June 1997 10:57:34
From: Rick Bronson rick@efn.org
Here is similiar way to grep for files in a directory tree. This
method uses xargs and as such does not suffer from the max chars in
a command line limit.
sea ()
{
find . -name "$2" -print | xargs grep -i "$1"
}
I've defined it as a function in my .bashrc file, you would use it
like:
sea "search this string" '*.[ch]'
Rick
Grepping
Date: Thu 19 June 1997 09:29:12
From: David Kastrup dak@neuroinformatic.ruhr-uni-buchum.de
Reply to "Grepping Files in a Tree Directory"
Well right. That's why most solutions to this problem are given
using the xargs command which will construct command lines of
appropriate size.
You'd write
find . -name \*.c -print|xargs grep foo
for this. This can be improved somewhat, however. If you suspect
that you have files containing newlines or otherwise strange
characters in them, try
find . -name \*.c -print0|xargs -0 grep foo --
This will use a special format for passing the file list from find to
xargs which can properly identify all valid filenames. The -- tells
grep that even strange file names like "-s" are to be interpreted as
file names.
Of course, we would want to have a corresponding file name listed even
if xargs calls a single grep in one of its invocation. We can manage
this with
find . -name \*.c -print0|xargs -0 grep foo -- /dev/null
This will have at least two file names for grep (/dev/null and one given by
xargs), so grep will print the file name for found matches.
The -- is a good thing to keep in mind when writing shell scripts.
Most of the shell scripts searching through directories you find
flying around get confused by file names like "-i" or
"xxx\
yyy"
and similar perversities.
David Kastrup
More on Grepping Files in a Tree
Date: Mon 02 June 1997 15:34:23
From: Chris Cox ccox@central.geasys.com
My favorite trick for look for a string (or strings - egrep) in
a tree:
$ find . -type f -print | xargs file | grep -i text |
cut -f1 -d: | xargs grep pattern
This is a useful technique for other things...not just
grepping.
Untarring/Zip
Date: Sun 22 June 1997 13:23:14
From: Mark Moran mmoran@mmoran.com
I read the following 2-cent tip and was excited to think that I've
finally reached a point in my 'linux' expertise I COULD contribute a
2-cent tip! I typically run:
tar xzf foo.tar.gz
to unzip and untar a program. But as Paul mentions the directory
structure isn't included in the archive and it dumps in your current
directory. Well before I do the above I run:
tar tzf foo.tar.gz
This will dump out to your console what going to be unarchived easily
allowing you to see if there's a directory structure!!!!
Mark
An Addition to Hard Disk Duplication (LG #18)
Date: Thu 12 June 1997 15:34:32
From: Andreas Schiffler schiffler@zkm.de
Not suprisingly, Linux can do that of course for free and - even from a
floppy bootimage for example (i.e. Slackware bootdisk console).
For identical harddrives the following will do the job:
cat /dev/hda >/dev/hdb
For non-identical harddrives one has to repartition the target first:
| fdisk /dev/hda | record the partitions (size, type) |
| fdisk /dev/hdb | create same partitions |
| cat /dev/hda1 >/dev/hdb1 | copy partitions |
| cat /dev/hda2 >/dev/hdb2 |
...
To create image files, simply redirect the target device to a file.
cat /dev/hda >image-file
To reinstall the MBR and lilo, just boot with a floppy using parameters
that point to the root partition (as in LILO> linux root=/dev/hda1) and
rerun lilo from within Linux.
Have fun
Andreas
Reply to ncftp (LG #18)
Date: Fri 20 June 1997 14:23:12
From: Andrew M. Dyer, adyer@mcs.com
To monitor an ftp session I like to use ncftp which puts up a nice
status bar. It comes in many linux distributions. When using the
standard ftp program you can also use the
hash
command which prints
a #
every 1K bytes received. Some ftp clients also have the bell
command which will send a bell character to your console for every file
transferred.
For grepping files in a directory tree I like to use the -exec
option to find. The syntax is cryptic, but there is no problem with
overflowing the shell argument list. A version of the command shown in
#18 whould be like this:
find . -name \*.c -exec grep foo {} /dev/null \;
(note the /dev/null forces grep to print the filename of the matched
file). Another way to do this is with the mightily cool xargs
program, which also solves the overflow problem and its a bit easier to
remember:
find . -name \*.c -print | xargs grep foo /dev/null
(this last one is stolen from "UNIX Power Tools" by Jerry Peek, Tim
O'Reilly and Mike Loukides - a whole big book of 2 cent tips.
For disk duplication we sometimes use a linux box with a secondary
IDE controller, and use
dd
to copy the data over.
dd if=/dev/hdc of=/dev/hdd bs=1024k
this would copy the contents of /dev/hdc to /dev/hdd. The bs=1024k
tells linux to use a large block size to speed the transfer.
Sockets and Pipes
Date: Thu, 12 Jun 1997 23:22:38 +1000 (EST)
From: Waye-Ian Cheiw, itchy@jaguar.snafu.com
Hello!
Here's a tip!
Ever tried to pipe things, then realised what you want to pipe to is on another
machine?
spiffy $ sort < file
sh: sort: command not found
spiffy $ # no sort installed here! gahck!
Try "socket", a simple utility that's included in the Debian distribution.
Socket is a tool which can treat a network connection as part of a pipe.
spiffy $ cat file
c
b
a
spiffy $ cat file | socket -s 7000 & # Make pipe available at port 7000.
spiffy $ rlogin taffy
taffy $ socket spiffy 7000 | sort # Continue pipe by connecting to spiffy.
a
b
c
It's also very handy for transferring files and directories in a snap.
spiffy $ ls -F
mail/ project/
spiffy $ tar cf - mail project | gzip | socket -qs 6666 &
spiffy $ rlogin taffy
taffy $ socket spiffy 6666 | gunzip | tar xf -
taffy $ ls -F
mail/ project/
The -q switch will close the connection on an end-of-file and conveniently
terminate the pipes on both sides after the transfer.
It can also connect a shell command's input and output to a socket. There is
also a switch, -l, which restarts that command every time someone connects to
the socket.
spiffy $ socket -s 9999 -l -p "fortune" &
spiffy $ telnet localhost 9999
"Baseball is ninety percent mental. The other half is physical."
Connection closed by foreign host.
Will make a cute service on port 9999 that spits out fortunes.
-- Ian!!
Hex Dump
Date: Tue 24 June 1997 22:54:12
From: Arne Wichmann aw@math.uni-sb.de
Hi.
One of my friends once wrote a small vi-compatible hex-editor. It can be
found (as source) under vieta.math.uni-sb.de:/pub/misc/hexer-0.1.4c.tar.gz
More on Hex Dump
Date: Wed, 18 Jun 1997 10:15:26 -0700
From: James Gilb p27451@am371.geg.mot.com
I liked your gawk solution to displaying hex data. Two things (which
people have probably already pointed out to you).
- If you don't want similar lines to be replaced by * *, use the -v
option to hexdump. From the man page:
-v The -v option causes hexdump to display all input data.
Without the -v option, any number of groups of output lines,
which would be identical to the immediately preceding group
of output lines (except for the input offsets), are replaced
with a line comprised of a single asterisk.
- In emacs, you can get a similar display using ESC-x hexl-mode. The
output looks something like this:
00000000: 01df 0007 30c3 8680 0000 334e 0000 00ff ....0.....3N....
00000010: 0048 1002 010b 0001 0000 1a90 0000 07e4 .H..............
00000020: 0000 2724 0000 0758 0000 0200 0000 0000 ..'$...X........
00000030: 0000 0760 0004 0002 0004 0004 0007 0005 ...`............
00000040: 0003 0003 314c 0000 0000 0000 0000 0000 ....1L..........
00000050: 0000 0000 0000 0000 0000 0000 2e70 6164 .............pad
00000060: 0000 0000 0000 0000 0000 0000 0000 0014 ................
00000070: 0000 01ec 0000 0000 0000 0000 0000 0000 ................
00000080: 0000 0008 2e74 6578 7400 0000 0000 0200 .....text.......
00000090: 0000 0200 0000 1a90 0000 0200 0000 2a98 ..............*.
(I don't suppose it is supprising that emacs does this, after all, emacs
is not just and editor, it is its own operating system.)
Reply to Z Protocol
Date: Mon 09 June 1997 19:34:54
From: Gregor Gerstmann gerstman@tfh-berlin.de
In reply to my remarks regarding file transfer with the z protocol
in LinuxGazette issue17, April 1997, I received an e-mail that may
be interesting to others too:
Hello!
I noticed your article in the Linux Gazette about the sz command, and really
don't think you need to split up your downloads into smaller chunks.
The sz command uses the ZMODEM protocol, which is built to handle transmission
errors. If sz reports a CRC error or a bad packet, it does not mean that the
file produced by the download will be tainted. sz automatically retransmits
bad packets.
If you have an old serial UART chip ( 8250 ), then you might be getting
intermittent serial errors. If the link is unreliable, then sz may spend most
of its time tied up in retransmission loops.
In this case, you should use a ZMODEM window to force the sending end to expect
an `OK' acknowledgement every few packets.
sz -w1024
Will specify a window of 1024 bytes.
-- Ian!!
Published in Linux Gazette Issue 19, July 1997
This page maintained by the Editor of Linux Gazette,
gazette@ssc.com
Copyright © 1997 Specialized Systems Consultants, Inc.
"Linux Gazette...making Linux just a little more fun!"
|
Contents:
|
News in General
SPAM Counter Attack!
If you'd like to have your voice heard regarding SPAM mail, why don't you
consider writing a letter to your representative?
If you're not sure of who your representatives are, check the Congressional
websites:
The postal addresses for your members are:
| The Honorable (Senator name) | The Honorable (Rep. name) |
Washington, DC 20510 | Washington, DC 20515 |
The letter doesn't have to be long... two paragraphs is as effective as 10
pages. And you don't need to write different letters, the same one can be
sent to each Member. (Just remember to change the mailing address!)
Linux-Access Web Pages
The Center for Disabled Student Services at the University of
Utah in Salt Lake City Utah, today announced it's newly re-designed
linux-access web pages. linux-access is a mailing list hosted by
CDSS which is used by both developers and users of the Linux operating
system in order to aid development and integration of access related
technology into the Linux OS and available software.
Both users and developers of Linux are encouraged to join the
mailing list and help Linux become more accessible to everyone. Among
those encouraged to subscribe to the list are companies making Linux
distributions so that they can incorporate access technology into their
products as well as get valuable feedback from users.
Location of the new pages is at:
http://ssv1.union.utah.edu/linux-access/.
Location of the blinux FTP mirror is at
ftp://ssv1.union.utah.edu/pub/mirrors/blinux/.
An archive of the mailing list can be found on the Linux v2 Information HQ
site at:
http://www.linuxhq.com/lnxlists/linux-access/.
Supreme Court Ruling
The U.S. Supreme Court extended free-speech rights
to cyberspace in its recent ruling striking down a federal law
that restricted indecent pictures and words on the Internet computer
network.
The court declared the law that bans the dissemination of
sexually explicit material to anyone younger than 18 unconstitutional.
"Notwithstanding the legitimacy and importance of the congressional goal
of protecting children from harmful materials, we agree ... that the
statute abridges 'freedom of speech' protected by the First Amendment,"
Justice John Paul Stevens said for the court majority in the 40-page
opinion.
The ruling represented a major victory for the American Civil Liberties
Union (ACLU) and groups representing libraries, publishers and the
computer on-line industry, which brought the lawsuit challenging the law.
The Power OS
Matthew Borowski has created a new website featuring Linux information. Entitled
"Linux - THE POWER OS", and featuring Linux links, software, help,
and a discussion forum, Linux - THE POWER OS is also a member of the
Linux Webring.
The software listing is top-of-the-line, featuring a list of powerful
applications that will change the way you make use of Linux. The modem
setup section will help you get your modem working under Linux,
and the StarOffice-miniHOWTO will help fix Libc problems when
installing Staroffice under Linux.
If you have a chance, visit "Linux - THE POWER OS" at:
http://www.jnpcs.com/mkb/linux
or
http://www.mkb.home.ml.org/linux/
For more information write to
mkb@poboxes.com
June 1997 PowerPC Project
The Linux for PowerPC project announces its June 1997 CD of the Linux
operating system for the PowerPC. The CD is the second release following
the first one in January 1997. The June release is significantly faster
and has improved memory handling. It now contains over 400 different
software packages and everything needed to install and run Linux on any
of the PowerPC machines manufactured by Be Inc, Apple Computer, IBM,
Motorola and most other manufactures of PowerPC computers. Go to
http://www.linuxppc.org/ to order your own CD or to find out more
about
Sunsite Link
Check out
http://sunsite.unc.edu/paulc/liv
This lets you view the contents of SunSITE's /pub/Linux/Incoming
directory, but extracts all the descriptions out of the map files (.lsm)
and displays them in a table. It has links for 24 hours/7 day/14 day and
28 day lists.
GLUE Announcement
Caldera has announced that it will give a free copy of OpenLinux
Lite on CD-ROM for each group member of GLUE. Caldera, Inc.
(http://www.caldera.com/) is located in Provo, Utah. For full details on
GLUE and to register your group as a member, visit the GLUE web site at
http://www.ssc.com/glue.
Software Announcements
Woven Goods for LINUX
World-Wide Web (WWW) Applications and Hypertext-based Information about
LINUX. It is ready configured for the Slackware Distribution and
currently
tested with Version 3.2 (ELF). The Power Linux LST Distribution contains
this collection as an integral part with some changes.
The Collection consists of five Parts, so it can be used for multiple
purposes depending on the installed Parts:
The five Parts of Woven Goods for LINUX are:
- World-wide Web Browser
The World-wide Web Browser from Netscape for X11 and Lynx for
ASCII terminals.
- LINUX Documents
The LINUX Documents contain the HTML Pages of Woven Goods for
LINUX,
FAQs, HOWTOs, LDP Documents and more in different formats like
Hypertext Markup Language (HTML), Text, PDF and Postscript.
- World-wide Web Server
The Apache World-wide Web Server with additional CGI Scripts for
Statistics, viewing MAN Pages and Counters, Glimpse Search Engine
and
the Documentation for Apache Server. Furthermore the Apache Module
PHP/FI as well as the BSCW system and the necessary Python
interpreter
are included.
- Hypertext Markup Language
The HTML-Editor asWedit allows the creation of HTML-Pages.
Some Graphic Tools allow the creation and modification of GIFs.
- External Viewers
The external Viewers are nessesary to present Information which can
not
be viewed by the WWW Browsers. Only the usefull Viewers (xanim,
acroread, ia, raplayer, str, splay, swplayer, vrweb, etc.) are
included
which are not part of the Slackware Distribution (xv, ghostview,
showaudio).
Availabilty & Download
Woven Goods for LINUX is available via anonymous FTP from:
ftp://ftp.fokus.gmd.de/pub/Linux/woven
Installation
For Installation Instructions see the Installation Guide:
ftp://ftp.fokus.gmd.de/pub/Linux/woven/README.install or
http://www.fokus.gmd.de/linux/install.html
Qbib Version 1.1
Qbib is a bibliography management system based on Qddb. Features include
the Qddb database, import BibTeX .bib giles, custom export options and a
friendly user-interface just to name a few.
For more information about Qbib (including an on-line manual),
see
http://www.hsdi.com/qddb/commercial
To order Qbib or other Qddb products/services, visit the Qddb store:
http://www.hsdi.com/qddb/orders
WipeOut Version 1.07
WipeOut is an integrated development environment for C++ and Java. It
contains project manager, class browser, make tool, central text editor
with syntax highlighting and a debugger frontend. WipeOut is available
for Linux and SunOS/Solaris both under XView.
For the new release we have especially extended the class browser and
the text editor.
Check out the changes list for all new features and fixed bugs.
You can obtain the software and documentation at:
http://www.softwarebuero.de/ndex-eng.html
Published in Linux Gazette Issue 19, July 1997
This page written and maintained by the Editor of Linux Gazette,
gazette@ssc.com
Copyright © 1997 Specialized Systems Consultants, Inc.
"Linux Gazette...making Linux just a little more fun!"
Contents:
Mounting Disks Under Red Hat 4.0
From: Bigby, Bruce W. bbigby@frontiernet.net
Hi. The RedHat 4.0 control-panel has an interesting problem. I have
two entries in my /etc/fstab file for my SCSI Zip Drive--one for
mounting a Win95 Zip removable disk and another for mounting a removable
Linux ext2fs disk--
/dev/sda4 /mnt/zip ext2fs rw,noauto 0 0
/dev/sda4 /mnt/zip95 vfat rw,noauto 0 0
I do this so that I can easily mount a removable zip disk by supplying
only the appropriate mount point to the mount command--for example, by
supplying
mount /mnt/zip
when I want to mount a Linux ext2fs disk, and
mount /mnt/zip95
when I want to mount a Windows 95 Zip disk.
Yes,
I do this all the time (except that I use the command
line for all of this -- and vi to edit my fstab). I also
add the "user" and a bunch of "nosuid,nodev,..." parameters
to my options field. This allows me or my wife (the only
two users with console access to the machine) to mount a
new magneto optical, floppy, or CD without having to
'su').
Unfortunately, the control-panel's mount utility treats the two lines as
duplicates and removes the additional lines that begin with /dev/sda4.
Consequently, the control panel's mount utility only sees the first
line,
/dev/sda4 /mnt/zip ext2fs rw,noauto 0 0
In addition, the utility also modifies my original /etc/fstab. I do not
Bummer! Since I don't use the GUI controls I never noticed
that.
desire this behavior. I prefer that the utility be fairly dumb and not
modify my original /etc/fstab. Has RedHat fixed this problem in 4.2?
I don't know. There are certainly enough other fixes and
upgrades to be worth installing it (although -- with a .1
version coming out every other month -- maybe you want to
just download selective fixes and wait for the big 5.0).
(My current guess -- totally unsubstantiated by even
an inside rumor -- is that they'll shoot for integrating
glibc -- the GNU C library -- into their next release.
That would be a big enough job to warrant a jump in
release numbers).
Can I obtain the sources and modify the control-panel's mount utility so
that it does not remove, "so-called," duplicates?
Last I heard the control-panel was all written in Python
(I think they converted all the TCL to Python by 4.0)
In any event I pretty sure that it's TCL, Python and Tk
(with maybe some bash for some parts). So you already have
the sources.
The really important question here is why you aren't asking
the support team at RedHat (or at least posting to their
"bugs@" address). This 'control-panel' is certainly
specific to Red Hat's package.
According to the bash man page, bash is supposed to source the .profile,
or .profile_bash, in my home directory. However, when I login, bash
does not source my .profile. How can I ensure that bash sources the
.profile of my login account--$HOME/.profile?
The man page and the particular configuration (compilation)
options in your binary might not match.
You might have an (empty?) ~/.bash_profile or ~/.bash_login
(the man page looks for these in that order -- with .profile
being the last -- and only it sources the first of them that
it finds).
You might have something weird in your /etc/profile or
/etc/bashrc that's preventing your ~/.bash_* or ~/.profile
from being sourced.
Finally you might want to double check that you really are
running bash as your login shell. There could be all sorts
of weird bugs in your configuration that effectively start
bash and fail to signal to it that this is a "login" shell.
Normally login exec()'s bash with an "ARG[0]" of "-bash"
(preceding the name with a dash). I won't get into the
gory details -- but if you were logging in with something that
failed to do this: bash wouldn't "know" that it was a login
shell -- and would behave as though it were a "secondary"
shell (like you invoked it from your editor)).
If all else fails go over to prep.ai.mit.edu and grab the
latest version of the GNU bash sources. Compile them
yourself.
--
Jim
Weird LILO Problem
From: David Runnels david_runnels@smb.com
Hi Jim. I read your column in the Linux Gazette and I have a question. (If I
should have submitted it some other way I apologize.)
I recommend using the tag@starshine.org address for now.
At some point I hope to have SSC set up a tag@gazette.ssc.com
address -- or maybe get linux.org to give me an account and
set up some custom mail scripts.
I've been using Linux casually for the last couple of years and several
months ago I installed RedHat 4.0 on the second IDE drive of a Win95
system. Though I've used System Commander in the past I don't like
using it with Win95 so I had the RedHat install process create a boot
floppy. This has always worked fine, and I made a second backup floppy
using dd) which I also made sure booted fine.
This probably isn't really a "boot" floppy. It sounds
like a "lilo" floppy to me. The difference is that a
boot floppy has a kernel on it -- a "lilo" floppy just has
the loader on it.
The confusing thing about Linux is that it can be
booted in so many ways. In a "normal" configuration
you have Lilo as the master boot program (on the first
hard drive -- in the first sector of track 0 -- with
the partition table). Another common configuration places
lilo in the "superblock" (logical boot record) of the
Linux "root" partition (allowing the DOS boot block,
or the OS/2 or NT boot manager -- or some third party
package like System Commander) to process the partition
table and select the "active" partition -- which *might*
be the Linux root partition.
Less common ways of loading Linux: use LOADLIN.EXE
(or SYSLINUX.EXE) -- which are DOS programs that can
load a Linux kernel (kicking DOS out from under them
so to speak), put Lilo on a floppy (which is otherwise
blank) -- or on a none Linux boot block (which sounds
like your situation).
Two others: You can put Lilo on a floppy *with* a
Linux kernel -- or you can even write a Linux kernel
to a floppy with no lilo. That last option is rarely
used.
The point of confusion is this: LILO loads the Linux
kernel using BIOS calls. It offers one the opportunity
to pass parameters to the kernel (compiled into it's
boot image via the "append" directive in /etc/lilo.conf --
or entered manually at boot time at the lilo prompt).
Another source of confusion is the concept that LILO
is a block of code and data that's written to a point
that's outside the filesystems on a drive -- /sbin/lilo
is a program that writes this block of boot code according
to a set of directives in the /etc/lilo.conf. It's best
to think of the program /sbin/lilo as a "compiler" that
"compiles" a set of boot images according to the
lilo.conf and writes them to some place outside of your
filesystem.
Yet another source of confusion is that the Linux
kernel has a number of default parameters compiled into
it. These can be changed using the 'rdev' command
(which was originally used to set the "root device"
flags in a kernel image file). 'rdev' basically
patches values into a file. It can be be used to set
the "root device," the "initial video mode" and a
number of other things. Some of these settings can
be over-ridden via the LILO prompt and append lines.
LOADLIN.EXE can also pass parameters to the kernel that
it loads.
There's a big difference between using a kernel image written
directly on a floppy -- and a LILO that's built to load an
image that's located on a floppy filesystem (probably minix
or ext2fs). With LILO the kernel must be located on some
device that is accessible with straight BIOS calls.
This usually prevents one from using LILO to boot off of a
third IDE or SCSI disk drive (since most systems require a
software driver to allow DOS or other OS' to "see" these
devices). I say "usually" because there are some BIOS' and
especially some BIOS extensions on some SCSI and EIDE
controllers that may allow LILO to access devices other than
the first two floppies and the first two hard drives. However,
those are rare. Most PC hardware can only "see" two floppy
drives and two hard drives -- which must be on the same
controller -- until an OS loads some sort of drivers.
In the case where a kernel is directly located on the
raw floppy -- and in the case where the kernel is
located on the floppy with LILO -- the kernel has the
driver code for your root device (and controllers) built
in. (There are also complex new options using 'initrd'
-- an "initial RAM disk" which allows a modular kernel
to load the drivers for it's root devices.
Yet another thing that's confusing to the DOS user -- and
most transplants from other forms of Unix -- is that the
kernel doesn't have to be located on the root device. In
fact LOADLIN.EXE requires that the kernel be located on
a DOS filesystem.
To make matters more complicated you can have multiple
kernels on any filesystem, any of them might use any
filesystem as their root device and these relationships
(between kernel and root device/filesystem can be set
in several ways -- i.e. by 'rdev' or at compile time,
vs. via the LOADLIN or LILO command lines).
I recommend that serious Linux users reserve a small
(20 or 30 Mb) partition with just a minimal installation
of the root/base Linux software on it. This should be
on a separate device from your main Linux filesystems.
Using this you have an alternative (hard drive based)
boot method which is much faster and more convenient than
digging out the installation boot/root floppies (or having
to go to a working machine and build a new set!). I recommend
the same thing for most Solaris and FreeBSD installations.
If you have a DOS filesystem on the box -- at least stash a
copy of LOADLIN.EXE and a few copies of your favorite kernels
in C:\LINUX\ (or wherever).
Now that more PC SCSI cards support booting off of CD-ROM's
(a feature that's been long overdue!) you can get by
without heeding my advice -- IF YOU HAVE SUCH A CONTROLLER
AND A CD TO MATCH.
(Incidentally -- I found out quite by
accident that the Red Hat 4.1 CD is "bootable"
on Adaptec 2940 controllers -- if you have the
Adaptec configured to allow it. I've also heard
that the NCR SymBIOS PCI controller supports this
-- though I haven't tested that yet).
In any event we should all make "rescue disks" --
unfortunately these are trickier than they should be.
Look for the Bootdisk HOWTO for real details about this.
About a week ago I put the Linux floppy in the diskette drive, reset
the machine and waited for the LILO prompt. Everything went fine, but
all I got were the letters LI and everything stopped. I have tried
several times, using the original and the backup diskette, with the
same results.
Did you add a new drive to the system?
I have done nothing (that I can think of!) to my machine and I'm at a
loss as to what might be causing this. Just to ensure that the floppy
drive wasn't acting funny, I've booted DOS from it and that went fine.
When you booted DOS where you able to see the drive?
I'd get out your installation floppy (or floppies --
I don't remember whether Red Hat 4.0 had a single
floppy system or not -- 4.1 and 4.2 only require one
for most hardware). Boot from that and choose "rescue"
or switch out of the installation script to a shell
prompt. You should then be able to attempt mounting
your root filesystem.
If that fails you can try to 'fsck' it. After that
it's probably a matter of reinstallation and restoring
from backups.
Any ideas you have would be appreciated. Thanks for your time.
Dave Runnels
Glad I could help.
Running FileRunner
David E. Stern kotsya@u.washington.edu
I wanted to let you know that you were right about relying too heavily
on rpm. In the distant past, I used file text-based file compression
utilities, so I tried it again and tarballs are actually quite nice. I
also found that rpm --nodeps will help. Tarballs are also nice because
not all apps are distributed with rpm. (bonus! :-) I'm also told that
multiple versions of tcl/tlk can peacably coexist, although rpm won't
allow it by default. Another ploy with rpm which I didn't see
documented was that to avoid circular dependencies, update multiple rpms
at the same time; i.e.: rpm -Uvh app1.rpm app2.rpm app3.rpm . Another
thing I learned about was that there are some non-standard (contributed)
libraries that are required for certain apps, like afio and xpm. Thanks
for the great ideas and encouragement.
The end goal: to install FileRunner, I simply MUST have it!
My intermediate goal is to install Tcl/Tk 7.6/4.2, because FileRunner
needs these to install, and I only have 7.5/4.1 . However, when I try to
upgrade tcl/tlk, other apps rely on older tcl/tk libraries, at least that's
what the messages allude to:
libtcl7.5.so is needed by some-app
libtk4.1.so is needed by some-app
(where some-app is python, expect, blt, ical, tclx, tix, tk, tkstep,...)
I have enough experience to know that apps may break if I upgrade the
libraries they depend on. I've tried updating some of those other apps,
but I run into further and circular dependencies--like a cat chasing it's
tail.
In your opinion, what is the preferred method of handling this scenario?
I must have FileRunner, but not at the expense of other apps.
It sounds like you're relying too heavily on RPM's.
If you can't afford to risk breaking your current stuff,
and you "must" have the upgrade you'll have to do some
stuff beyond what the RPM system seems to do.
One method would be to grab the sources (SRPM or tarball)
and manually compile the new TCL and tk into /usr/local
(possibly with some changes to their library default
paths, etc). Now you'll probably need to grab the
FileRunner sources and compile that to force it to use the
/usr/local/wish or /usr/local/tclsh (which, in turn, will
use the /usr/local/lib/tk if you've compiled it all right).
Another approach is to set up a separate environment
(separate disk, a large subtree of an existing disk
-- into which you chroot, or a separate system entirely)
and test the upgrade path where it won't inconvenience you
by failing. A similar approach is to do a backup, test your
upgrade plan -- (if the upgrade fails, restore the backup).
Thanks, -david
You're welcome.
This is a big problem in all computing environments (and
far worse in DOS, Windows, and NT systems than in most
multi-user operating systems. At least with Unix you have
the option of installing a "playpen" (accessing it with the
chroot call -- or by completely rebooting on another partition
if you like).
Complex interdepencies are unavoidable unless you require that
every application be statically linked and completely self-sufficient
(without even allowing their configuration files to be separate.
So this will remain an aspect of system administration where
experience and creativity are called for (and a good backup
may be the only thing between you and major inconvenience).
--
Jim
Adding Linux t a DEC XLT-366
From: Alex Pikus alex@webexpress.net
I have a DEC XLT-366 with NTS4.0 and I would like to add Linux to it. I
have been running Linux on an i386 for a while.
I have created 3 floppies:
- Linload.exe and MILO (from DEC site)
- Linux kernel 2.0.25
- RAM disk
I have upgrade AlphaBIOS to v5.24 (latest from DEC) and added a Linux
boot option that points to a:\
You have me at a severe disadvantage. I've never
run Linux on an Alpha.
So I'll have to try answering this blind.
When I load MILO I get the "MILO>" prompt without any problem. When I
do show
or boot ...
at the MILO I get the following result ...
SCSI controller gets identified as NCR810 on IRQ 28 ... test1 runs and
gets stuck "due to a lost interrupt" and the system hangs ...
In WinNTS4.0 the NCR810 appears on IRQ 29.
My first instinct is the ask if the autoprobe code in
Linux (Alpha) is broken. Can you use a set of command-line
(MILO) parameters to tell pass information about your
SCSI controller to your kernel? You could also see about
getting someone else with an Alpha based system to compile
a kernel for you -- and make sure that it has values in
it's scsi.h file that are appropriate to your system -- as
well as insuring that the corrective drivers are built in.
How can make further progress here?
It's a tough question. Another thing I'd look at
is to see if the Alpha system allows booting from a
CD-ROM. Then I'd check out Red Hat's (or Craftworks')
Linux for Alpha CD's -- asking each of them if they
support this sort of boot.
(I happened to discover that the Red Hat Linux 4.1 (Intel)
CD-ROM was bootable when I was working with one system that
had an Adaptec 2940 controller where that was set as an
option. This feature is also quite common on other Unix
platforms such as SPARC and PA-RISC systems -- so it is
a rather late addition to the PC world).
Thanks!
Alex.
Disk Support
From: Andrew Ng lulu@@asiaonline.net
Dear Sir,
I have a question to ask:
Does Linux support disks with density
2048bytes/sector?
Apparently not.
This is a common size for CD-ROM's -- but it not
at all normal for any other media.
I have bought a Fujitsu MO drive which support up to 640MB MO disks with
density 2048bytes/sector. The Slackware Linux system does not support
access to disks with this density. Windows 95 and NT support this density
and work very well. Is there any version of Linux which support
2048bytes/sector? If not, is there any project working on that?
I believe the drive ships with drivers for DOS, Windows,
Windows '95 and NT. The OS' don't "support it" the manufacturer
supports these OS'.
Linux, other the other hand, does support most hardware
(without drivers being supplied by the hardware manufacturers).
Granted we get some co-operation from many manufacturers.
Some even contribute code to the main kernel development.
We prefer the model where the hardware manufacturer releases
free code to drive their hardware -- whether that code is
written for Linux, FreeBSD or any other OS. Release it once
and all OS' can port and benefit by it.
I hear a lot of praise about Linux. Is Linux superior to Windows NT in all
aspect?
That's controversial question. Any statement like:
Is "foo" superior to "bar" in all aspects?
... is bound to cause endless (and probably acrimonious)
debate.
Currently NT has a couple of advantages: Microsoft is a
large company with lots of money to spend on marketing and
packaging. They are very aggressive in making "partnerships"
and building "strategic relationships" with the management of
large companies.
Microsoft has slowly risen to dominance in the core applications
markets (word processors, spreadsheets, and databases). Many
industry "insiders" (myself included) view this as being the
result of "trust"-worthy business practices (a.k.a. "verging
on monopolistic").
In other words may people believe that MS Word isn't the
dominant word processor because it is technically the superior
product -- but because MS was able to supply the OS features
they needed when they wanted (and perhaps able to slip the
schedules of certain releases during the critical development
phases of their competitors).
The fact that the OS, and the principal programming tools,
and the major applications are all from the same source has
generated a amazing amount of market antagonism towards
Microsoft. (Personally I think it's a bit extreme -- but
I can understand how many people feel "trapped" and understand
the frustration of thinking that there's "no choice").
Linux doesn't have a single dominant applications suite.
There are several packages out there -- Applixware, StarOffice,
Caldera's Internet Office Suite. Hopefully Corel's Java Office
will also be a useful to Linux, FreeBSD and other users
(including Windows and NT).
In addition to these "suites" there are also several individual
applications like Wingz (a spreadsheet system), Mathematica,
(the premier symbolic mathematics package), LyX (the free word
processor -- LaTeX front-end -- that's under development),
Empress, /rdb (database systems), Flagship and dbMan IV
(xBase database development packages), Postgres '95, mSQL,
InfoFlex, Just Logic's SQL, MySQL (database servers) and a
many more. (Browse through the Linux Journal _Buyer's_Guide_
for a large list -- also waltz around the web a bit).
Microsoft's SQL Server for NT is getting to be pretty good.
Also, there are alot of people who program for it -- more
than you'll find for InfoFlex, Postgres '95 etc. A major
problem with SQL is that the servers are all different enough
to call for significant differences in the front end applications
-- which translates to lots of programmer time (and money!) if
you switch from one to another. MS has been very successful
getting companies to adopt NT Servers for their "small" SQL projects
(which has been hurting the big three -- Oracle, Sybase and
Informix). Unfortunately for Linux -- database programmers and
administrators are very conservative -- they are a "hard sell."
So Linux -- despite the excellent stability and performance --
is not likely to make a significant impact as a database server
for a couple of years at least. Oracle, Sybase and Informix
have "strategic relationships" with SCO, Sun, and other Unix
companies.
The established Unix companies viewed Linux as a threat until
recently. They now seem to see it as a mixed blessing. On the
up side Linux has just about doubled the number of systems
running Unix-like OS', attracted somewhere between two and
eight million new converts away from the "Wintel" paradigm,
and even wedged a little bit of "choice" into the minds of
the industry media. On the down side SCO can no longer charge
thousands of dollars for the low end of their systems. This
doesn't really affect Sun, DEC, and HP so much -- since they are
primarily hardware vendors who only got into the OS business to
keep their iron moving out the door. SCO and BSDI have the
tough fight since the bulk of their business is OS sales.
(Note: BSDI is *not* to be confused with the FreeBSD, NetBSD,
OpenBSD, or 386BSD (Jolix) packages. They are a company that
produces a commercial Unix, BSDI/OS. The whole Free|Net|Open-BSD
set of programming projects evolved out of the work of
Mr. and Mrs. Jolitz -- which was called 386BSD -- and I call
"Jolix" -- a name with I also spotted in the _Using_C-Kermit_
book from Digital Press).
So there don't seem to be any Oracle, SyBase, or Informix
servers available for Linux. The small guys like JustLogic
and InfoFlex have an opportunity here -- but it's a small
crack in a heavy door and some of them are likely to get their
toes broken in the process.
Meanwhile NT will keep getting market share -- because their
entry level still a tiny fraction of the price of any of the
"big guys."
I've just barely scratched the tip of the iceberg (to thoroughly
blend those metaphors). There are so many other aspects of
comparison it's hard to even list them -- let alone talk about
who Linux and NT measure up to them.
It's also important to realize that it's not just NT vs.
Linux. There are many forms of Unix -- most of them are
quite similar to Linux from a user and even from an
administrators point of view. There are many operating systems
that are vastly different than either NT (which is supposed to
be fundamentally based on VMS) and the various Unix variants.
There are things like Sprite (a Berkeley research project),
Amoeba and Chorus (distributed network operating systems),
EROS, and many others.
Here's a link where you can find out more about operating
systems in general:
Yahoo!
Computers and Internet: Operating Systems: Research
--
Jim
Legibility
From: Robert E Glacken glacken@bc.seflin.org
I use a 256 shade monochrome monitor. The QUESTIONS are invisible.
What questions?
What OS?
What GUI? (I presume that the normal text is visible in
text mode so you must be using a GUI of some sort)?
I wouldn't expect much from a monochrome monitor set to
show 256 (or even 127) shades of grey. That's almost no
one in the PC/Linux world that uses those -- so there almost
no one that tunes their color tables and applications to
support it.
Suggestions -- get a color screen -- or drop the GUI and
use text mode.
--
Jim
MetroX Problems
From: Allen Atamer atamer@ecf.toronto.edu
I am having trouble setting up my XServer. Whether or not I use MetroX
or Xfree86 to set it up it's still not working.
When I originally chose metrox to install, i got to the setup screen,
chose my card and resolution, saved and exited. Then i started up the
xwindows, and my screen loaded the Xserver, but the graphics were all
messed up. I exited, then changed some settings, and now i can't even
load the xserver. The Xerrors file says it had problems loading the
'core'.
Hmm. You don't mention what sort of video card you're using
or what was "messed up." As I've said many times in my
column -- I'm not must of an "Xpert" (or much of a "TeXpert"
for that matter).
MetroX and XFree86 each have their own support pages
on the web -- and there are several X specific newsgroups
where you'd find people who are much better with X than I.
Before you go there to post I'd suggest that you type up
the type of video card and monitor you have in excruciating
detail -- and make sure you go through the X HOWTO's and
the Red Hat manual. Also be sure to check the errata
page at Red Hat (http://www.redhat.com/errata.html) --
this will let you know about any problems that were discovered
after the release of 4.1.
One other thing you might try is getting the new version
(4.2 -- Biltmore) -- and check it's errata sheet. You can
buy a new set of CD's (http://www.cheapbytes.com is one
inexpensive source) or you can use up a bunch of bandwidth
by downloading it all. The middle road is to to download
just the parts you need.
I notice (looking at the errata sheets as I type this)
that XFree86 is up to version 3.3.1 (at least). This upgrade
is apparently primarily to fix some buffer overflow (security)
problems in the X libraries.
By the way, how do I mount what's on the second cd and read it?
(vanderbilt 4.1)
First umount the first CD with a command like:
umount /cdrom
Remove it.
Then 'mount' the other one with a command like:
mount -t iso9660 -o ro /cdrom /dev/scd0
... where /cdrom is some (arbitrary but extent) mount point
and /dev/scd0 is the device node that points to your CD drive
(that would be the first SCSI CD-ROM on your system --
IDE and various other CD's have different device names).
To find out the device name for your CD use the mount command
BEFORE you unmount the other CD. It will show each mounted
device and the current mount point.
Personally I use /mnt/cd as my mount point for most CD's.
I recommend adding an entry to your /etc/fstab file
(the "filesystems table" for Unix/Linux) that looks something
like this:
# /etc/fstab
/dev/scd0 /mnt/cd iso9660 noauto,ro,user,nodev,nosuid 0 0
This will allow you to use the mount and umount commands
as a normal user (without the need to su to 'root').
I also recommend changing the permissions of the mount
command to something like:
-rwsr-x--- 1 root console 26116 Jun 3 1996 /bin/mount
(chgrp console `which mount && chmod 4550 `which mount`)
... so that only members of the group "console" can use the
mount command. Then add your normal user account to that
group.
The idea of all this is to strike a balance between the
convenience and reduced "fumblefingers" exposure of running
the privileged command as a normal user -- and the potential
for (as yet undiscovered buffer overflows) to compromise the
system by "guest" users.
(I recommend similar procedures for ALL SUID binaries -- but
this is an advanced issue that goes *WAY* beyond the scope of
this question).
Allen,
You really need to get a copy of the "Getting Started"
guide from the Linux Documentation Project. This can be
downloaded and printed (there's probably a copy on your
CD's) or you can buy the professionally bound editions from
any of several publishers -- my favorite being O'Reilly &
Associates (http://www.ora.com).
Remember that the Linux Gazette "Answer Guy" is no
substitute for reading the manuals and participating in
Linux newsgroups and mailing lists.
--
Jim
Installing Linux
From: Aryeh Goretsky aryeh@tribal.com
[ Aryeh, I'm copying my Linux Gazette editor on this since I've put in
enough explanation to be worth publishing it ]
..... why ... don't they just call
it a disk boot sector . ....
Okay, I've just got to figure out what the problem is, then. Are
there any utilities like NDD for Linux I can run that will point
out any errors I made when entering the superblock info?
Nothing with a simple, colorful interface. 'fsck' is
at least as good with ext2 filesystems as NDD is with
FAT (MS-DOS) partitions. However 'fsck' (or, more specifically,
e2fsck) has a major advantage since the ext2fs was designed
to be robust. The FAT filesystem was designed to be simple
enough that the driver code and the rest of the OS could fit
on a 48K (yes, forty-eight kilobytes) PC (not XT, not AT, and
not even close to a 386). So, I'm not knocking NDD when I
say that fsck works "at least" as well.
However, fsck doesn't touch your MBR -- it will
check your superblock and recommand a command to restore
the superblock from one of the backups if yours is damaged.
Normally the newfs (like MS-DOS' FORMAT) or mke2fs
(basically the same thing) will scatter extra copies of the
superblock every 8K sectors across the filesystem (or so).
So there are usually plenty of backups.
So, usually, you'd just run fdisk to check your
partitions and /sbin/lilo to write a new MBR (or other
boot sector). /sbin/lilo will also update its own
"map" file -- and may (optionally) make a backup of
your original boot sector or MBR.
(Note: There was an amusing incident on
one of the mailing lists or newsgroups -- in which
a user complained that Red Hat had "infected his
system with a virus." It turns out that lilo had moved
the existing (PC/MBR) virus from his MBR to a
backup file -- where it was finally discovered.
So, lilo had actually *cured* his system of the
virus).
Actually when you run /sbin/lilo you're "compiling" the
information in the /etc/lilo.conf file and writing that
to the "boot" location -- which you specify in the .conf
file.
You can actually call your lilo.conf anything you like --
and you can put it anywhere you like -- you'd just have to
call /sbin/lilo with a -C switch and a path/file name.
/etc/lilo.conf is just the built-in default which the -C
option over-rides.
Here's a copy of my lilo.conf (which I don't actually use
-- since I use LOADLIN.EXE on this system).
As with many (most?) Unix configuration files the comments
start with hash (#) signs.
boot=/dev/hda
# write the resulting boot block to my first IDE hard drive's MBR.
# if this was /dev/hdb4 (for example) /sbin/lilo would write the
# resulting block to the logical boot record on the fourth partition
# of my second IDE hard drive. /dev/sdc would mean to write it to
# the MBR of the third SCSI disk.
# /sbin/lilo will print a warning if the boot location is likely to
# be inaccessible to most BIOS' (i.e. would require a software driver
# for DOS to access it).
## NOTE: Throughout this discussion I use /sbin/lilo to refer to the
## Linux executable binary program and LILO to refer to the resulting
## boot code that's "compiled" and written by /sbin/lilo to whatever
## boot sector your lilo.conf calls for. I hope this will minimize the
## confusion -- though I've liberally re-iterated this with parenthetical
## comments as well.
# The common case is to put boot=/dev/fd0H1440 to specify that the
# resulting boot code should be written to a floppy in the 1.44Mb
# "A:" drive when /sbin/lilo is run. Naturally this would require
# that you use this diskette to boot any of the images and "other"
# stanzas listed in the rest of this file. Note that the floppy
# could be completely blank -- no kernel or files are copied to it
# -- just the boot sector!
map=/boot/map
# This is where /sbin/lilo will store a copy of the map file --
# which contains the cylinder/sector/side address of the images
# and message files (see below)
# It's important to re-run /sbin/lilo to regenerate the map
# file any time you've done anything that might move any of
# these image or message files (like defragging the disk,
# restoring any of these images from a backup -- that sort
# of thing!).
install=/boot/boot.b
# This file contains code for LILO (the boot loader) -- this is
# an optional directive -- and necessary in this case since it
# simply specifies the default location.
prompt
# This instructs the LILO boot code to prompt the user for
# input. Without this directive LILO would just wait
# upto "delay" time (default 0 tenths of a second -- none)
# and boot using the default stanza.
# if you leave this and the "timeout" directives out --
# but you put in a delay=X directive -- then LILO won't
# prompt the user -- but will wait for X tenths of a second
# (600 is 10 seconds). During that delay the user can hit a
# shift key, or any of the NumLock, Scroll Lock type keys to
# request a LILO prompt.
timeout=50
# This sets the amount of time LILO (the boot code) will
# wait at the prompt before proceeding to the default
# 0 means 'wait forever'
message=/etc/lilo.message
# this directive tells /sbin/lilo (the conf. "compiler") to
# include the contents of this message in the prompt which LILO
# (the boot code) displays at boot time. It is a handy place to
# put some site specific help/reminder messages about what
# you call your kernels and where you put your alternative bootable
# partitions and what you're going to do to people who reboot your
# Linux server without a very good reason.
other=/dev/hda1
label=dos
table=/dev/hda
# This is a "stanza"
# the keyword "other" means that this is referring to a non-Linux
# OS -- the location tells LILO (boot code) where to find the
# "other" OS' boot code (in the first partition of the first IDE --
# that's a DOS limitation rather than a Linux constraint).
# The label directive is an arbitrary but unique name for this stanza
# to allow one to select this as a boot option from the LILO
# (boot code) prompt.
# Because it is the first stanza it is the the default OS --
# LILO will boot this partition if it reaches timeout or is
# told not to prompt. You could also over-ride that using a
# default=$labelname$ directive up in the "global" section of the
# file.
image=/vmlinuz
label=linux
root=/dev/sda5
read-only
# This is my "normal" boot partition and kernel.
# the "root" directive is a parameter that is passed to the
# kernel as it loads -- to tell the kernel where its root filesystem
# is located. The "read-only" is a message to the kernel to initially
# mount the root filesystem read-only -- so the rc (AUTOEXEC.BAT)
# scripts can fsck (do filesystem checks -- like CHKDSK) on it.
# Those rc scripts will then normally remount the fs in "read/write"
# mode.
image=/vmlinuz.old
label=old
root=/dev/sda5
append= single
read-only
# This example is the same except that it loads a different kernel
# (presumably and older one -- duh!). The append= directive allows
# me to pass arbitrary directives on to the kernel -- I could use this
# to tell the kernel where to find my Ethernet card in I/O, IRQ, and
# DMA space -- here I'm using it to tell the kernel that I want to come
# up in "single-user" (fix a problem, don't start all those networking
# gizmos) mode.
image=/mnt/tmp/vmlinuz
label=alt
root=/dev/sdb1
read-only
# This last example is the most confusing. My image is on some other
# filesystem (at the time that I run /sbin/lilo to "compile" this
# stanza). The root fs is on the first partition of the 2nd SCSI drive.
# It is likely that /dev/sdb1 would be the filesystem mounted under
# /mnt/tmp when I would run /sbin/lilo. However it's not "required"
# My kernel image file could be on any filesystem that was mounted
# /sbin/lilo will warn me if the image is likely to be inaccessible
# by the BIOS -- it's can't say for sure since there are a lot of
# BIOS' out there -- some of the newer SCSI BIOS' will boot off of a
# CD-ROM!
I hope that helps. The lilo.conf man page (in section 5) gives
*lots* more options -- like the one I just saw while writing this
that allows you to have a password for each of your images -- or
for the whole set. Also there are a number of kernel options
described in the BootPrompt-HOWTO. One of the intriguing ones is
panic= -- which allows you to tell the Linux kernel how long to
sit there displaying a kernel panic. The default is "forever" --
but you can use the append= line in your lilo.conf to pass a
panic= parameter to your kernel -- telling it how many seconds to
wait before attempting to reboot.
In the years that I've used Linux I've only seen a couple (like
two or three) kernel panics (that could be identified as such). Perhaps
a dozen times I've had a Linux system freeze or go comatose enough that
I hard reset it. (Most of those involve very bad hardware IRQ conflicts).
Once I've even tricked my kernel into scribbling garbage all over one of
my filesystems (don't play with linear and membase in your XConfig file --
and, in particular don't specify a video memory base address that's
inside of your system's RAM address space).
So I'm not sure if setting a panic= switch would help much. I'd be
much more inclined to get a hardware watchdog timer card and enable
the existing support for that in the kernel. Linux is the only PC
OS that I know of that comes with this support "built-in"
For those that aren't familiar with them a watchdog timer card is
a card (typically taking an ISA slot) that implements a simple count-down
and reset (strobing the reset line on the system bus) feature. This is
activated by a driver (which could be a DOS device driver, a Netware
Loadable Module, or a little chunk of code in the Linux kernel. Once
started the card must be updated periodically (the period is set as
part of the activation/update). So -- if the software hangs -- the
card *will* strobe the reset line.
(Note: this isn't completely fool-proof. Some hardware states might
require a complete power cycle and some sorts of critical server failures
will render the systems services unavailable without killing the
timer driver software. However it is a good sight better than just
hanging).
These cards cost about $100 (U.S.) -- which is a pity since there's
only about $5 worth of hardware there. I think most Sun workstations
have this feature designed into the motherboard -- which is what
PC manufacturers should scramble to do.
AG
At 11:43 AM 6/10/97 -0700, you wrote:
Subject: Once again, I try to install Linux...
...and fail miserably.
This is getting depressing.
Someone wanna explain this whole superblock concept to me? Use
small words....
Aryeh,
Remember master boot records (MBR's)? Remember "logical"
boot records -- for volume boot records?
A superblock is the Unix term for a logical boot record.
Linux uses normal partitions that are compatible with the
DOS, OS/2, NT (et al) hard disk partitioning scheme.
To boot Linux you can use LILO (the Linux loader) which can
be written to your MBR (most common), to your "superblock"
or to the "superblock" of a floppy. This little chunk of code
contains a reference (or "map") to the device and logical sector
of one or more Linux kernels or DOS (or OS/2) bootable partitions.
There is a program called "lilo" which "compiles" a lilo.conf
(configuration file) into this LILO "boot block" and puts it
onto the MBR, superblock or floppy boot block for you. This is
the source of most of the confusion about LILO. I can create a
boot floppy with nothing put this boot block on it -- no
kernel, no filesystems, nothing. LILO doesn't care where I put
any of my linux kernels -- so long as it can get to it using
BIOS calls (which usually limits you to putting the kernel on
the one of the first two drives connected to the first drive
controller on your system).
Another approach is to use LOADLIN.EXE -- this is a DOS
program that loads a Linux (or FreeBSD) kernel. The advantage
of this is that you can have as many kernel files as you like,
and they can be located on any DOS accessible device (even if you
had to load various weird device drivers to be able to see that
device.
LOADLIN.EXE is used by some CD-ROM based installation packages
-- avoiding the necessity of using a boot floppy.
The disadvantages of LOADLIN include the fact that you may have
loaded some device drivers and memory managers that have re-mapped
(hooked into) critical BIOS interrupt vectors. LOADLIN often needs
a "boot time hardware vector table" (which it usually writes as
C:\REALBIOS.INT -- a small hidden/system file). Creating this file
involves booting from a "stub" floppy (which saves the table) and
rebooting/restarting the LOADLIN configuration to tell it to
copy the table from the floppy to your HD. This must be done whenever
you change video cards, add any controller with a BIOS extension
(a ROM) or otherwise play with the innards of your machine.
Call me and we can go over your configuration to narrow down the
discussion. If you like you can point your web browser at
www.ssc.com/lg and look for articles by "The Answer Guy" there.
I've described this a greater length in some of my articles there.
--
Jim
Adding Programs to the Pull Down Menus
From: Ronald B. Simon rbsimon@anet.bna.boeing.com
Thank you for responding to my request.
By the way I am using RedHat release 4 and I think TheNextLevel window
manager. I did find a .fvwm2rc.programs tucked away in...
Ronald,
TheNextLevel is an fvwm derivative.
/etc/X11/TheNextLevel/. I added a define ProgramCM(Title,,,program
name) and under the start/applications menu I saw Title. When I put
the cursor over it and pressed the mouse button, everything froze. I
came to the conclusion that I am in way over my head and that I
probably need to open a window within the program that I am trying to
execute. Any way I will search for some 'C' code that shows me how to
do that.
Thanks again!
I forgot to mention that any non X program should be run
through an xterm.
This is normally done with a line in your rc file like:
Exec "Your Shell App" exec xterm -e /path/to/your/app &
... (I'm using fvwm syntax here -- I'll trust you to translate
to TNL format).
Try that -- it should fix you right up.
Also -- when you think your X session is locked up --
try the Ctrl-Alt-Fx key (where Fx is the function key
that corresponds to one of your virtual consoles).
This should switch you out of GUI mode and into your
normal console environment. You might also try Alt-SysReq
(Print-Screen on most keyboards) followed by a digit from
the alphanumeric portion of you keyboard (i.e. NOT from the
numeric keypad). This is an alternative binding for VC
switching that might be enabled on a few systems.
If all of that fails you can try Ctrl-Alt-Backspace. This
should (normally) signal the X server to shutdown.
Mostly I doubt that your server actually hung. I suspect
that you confused it a bit by running a non-X program
not "backgrounded" (you DO need those trailing ampersands)
and failing to supply it with communications channel back to
X (an xterm).
Please remember that my knowlege of X is very weak. I
hardly ever use and almost never administer/customize it.
So you'll want to look at the L.U.S.T. mailing list, or
the comp.windows.x or (maybe) the comp.os.linux.x (although
there is nothing to these questions which is Linux specific).
I looked extensively for information about TheNextLevel
on the web (in Yahoo! and Alta Vista). Unfortunately
the one page that almost all of the references pointed
to was down
The FVWM home page is at:
http://www3.hmc.edu/~tkelly/docs/proj/fvwm.html
--
Jim
Linux Skip
From: Jesse Montrose jesse@spine.com
Time warp:
This message was lost in my drafts folder while I was
looking up some of the information. As it turns out the
wait was to our advantage. Read on.
Date: Sun, 16 Mar 1997 13:54:34 -0800
Greetings, this question is intended for the Answer Guy associated with
the Linux Gazette..
I've recently discovered and enjoyed your column in the Linux Gazette,
I'm hoping you might have news about a linux port of sun's skip ip
encryption protocol.
Here's the blurb from skip.incog.com:
SKIP secures the network at the IP packet level. Any networked
application gains the benefits of encryption, without requiring
modification. SKIP is unique in that an Internet host can send an
encrypted packet to another host without requiring a prior message
exchange to set up a secure channel. SKIP is particularly well-suited
to IP networks, as both are stateless protocols. Some of the
advantages of SKIP include:
- No connection setup overhead
- High availability - encryption gateways that fail can reboot and
resume decrypting packets instantly, without having to
renegotiate (potentially thousands) of existing connections
- Allows uni-directional IP (for example, IP broadcast via
satellite or cable)
- Scalable multicast key distribution
- SKIP gateways can be configured in parallel to perform
instant-failover
I heard a bit about SKIP while I was at a recent IETF
conference. However I must admit that it got lost in
the crowd of other security protocols and issues.
So far I've paid a bit more attention to the Free S/WAN
project that's being promoted by John Gilmore of the
EFF.
I finally got ahold of a friend of mine (Hugh Daniel --
one of the architects of Sun's NeWS project -- and
well-known cypherpunk and computer security professional)
He explained that SKIP is the "Secure Key Interchange Protocol"
-- that is is a key management protocol (incorporated in
ISAKMP/Oakley).
For secure communications you need:
- Key management (which -- between strangers
requires some sort of RSA (Public Key) or
Diffie-Hellman key exchange or even some
variant of elliptic curve -- from what
I've heard).
- Encrypted Link (which will be built into
IPv6 and will be available as IPSec extensions
to IPv4 -- using tunnelled interfaces from
what I gather).
- Secure-DNS (this is related to the key management
problem -- we need a trustworthy source of
public key information -- Verisign and Thawte
offer commercial "Certification Authority"
services -- but the 'net needs something a
bit more open and standards based).
My employer is primarily an NT shop (with sun servers), but since I
develop in Java, I'm able to do my work in linux. I am one of about a
dozen telecommuters in our organization, and we use on-demand ISDN to
dial in directly to the office modem bank, in many cases a long distance
call.
I'm finally working on configuring my dial-on-demand ISDN
line here at my place. I've had diald (dial-on-demand over
a 28.8 modem) running for about a month now. I just want to
cut down on that dial time.
We're considering switching to public Internet connections, using skip
to maintain security. Skip binaries are available for a few platforms
(windows, freebsd, sunos), but not linux. Fortunately the source is
available (http://skip.incog.com/source.html) but it's freebsd, and I
don't know nearly enough deep linux to get it compiled (I tried making
source modifications).
If I understand it correctly SKIP is only a small part of
the solution.
Hopefully FreeS/WAN will be available soon. You can
do quite a bit with ssh (and I've heard of people
who are experimenting with routing through some
custom made tunnelled interface). FreeBSD and Linux
both support IP tunneling now.
For information on using ssh and IP tunnels to build a
custom VPN (virtual private network) look in this
month's issue of Sys Admin Magazine (July '97).
(Shameless plug: I have an article about C-Kermit appearing
in the same issue).
Another method might be to get NetCrypto. Currently the
package isn't available for Linux -- however McAfee is
working on a port. Look at http://www.mcafee.com
After much time with several search engines, the best I could come up
with was another fellow also looking for a linux version of skip :)
Thanks!
jesse montrose
Jesse,
Sorry I took so long to answer this question. However,
as I say, this stuff has changed considerably -- even in
the two months between the time I started this draft message
and now.
--
Jim
ActiveX for Linux
From: Gerald Hewes hewes@OpenMarket.com
Jim,
I read your response on ActiveX in the Linux Gazette.
At ../issue18/lg_answer18.html#active
Software AG is porting the non GUI portions of ActiveX called DCOM
to Linux. Their US site where it should be hosted appears down
as I write this e-mail message
but there is a link of their home page on a Linux DCOM beta:
http:/www.sotwareag.com
I beleive the link ought to be
http://www.sagus.com/prod-i~1/net-comp/dcom/index.htm
As for DCOM, its main value for the Linux community is in making
Microsoft Distributed Object Technology available to the Linux
community. Microsoft is trying to push DCOM over CORBA.
I know that MS is "trying to push DCOM over CORBA"
(and OpenDOC, and now, JavaBeans). I'm also aware that
DCOM stands for "distributed component object model" and
CORBA is the "common object request broker" and SOM is
IBM's "system object model" (OS/2).
The media "newshounds" have dragged these little bones
around and gnawed on them until we've all seen them.
Nonetheless I don't see its "main value to the Linux
community."
These "components" or "reusable objects" will not make
any difference so long as significant portions of their
functionality are tied to specific OS (GUI) semantics.
However, this coupling between specific OS' has been a
key feature of each of these technologies.
It's Apple's OpenDoc, IBM's DSOM, and Microsoft's DSOM!
While I'm sure that each as their merits from the programmer's
point of view (and I'm in no position to comment on their
relative technical pros or cons) -- I have yet to see any *benefit*
from a user or administrative point of view.
So I suppose the question here becomes:
Is there any ActiveX (DCOM) control (component)
that delivers any real benefit to any Linux user?
Do any of the ActiveX controls not have a GUI component
to them?
What does it mean to make the "non-GUI portions" of
DCOM available?
Is there any new network protocol that this gives
us? If so, what is that protocol good for?
For more information, checkout http://www.microsoft.com/oledev
While I encourage people to browse around -- I think
I'll wait until someone can point out one DCOM component,
one JavaBean, one CORBA object, or one whatever-buzzword-
you-want-to-call-it-today and can explain in simple "Duh!
I'm a user!" terms what the *benefit* is.
Some time ago -- in another venue -- I provided the net
with an extensive commentary on the difference between
"benefits" and "features." The short form is this:
I benefit is relevant to your customer. To
offer a benefit requires that you understand
your customer. "Features" bear no relation to
a customers needs. However mass marketing
necessitates the promotion of features -- since
the *mass* marketer can't address individual and
niche needs.
Example: Microsoft operating systems offer a "easy to use
graphical interfaces" -- first "easy to use" is highly subjective.
In this case it means that there are options listed on menus
and buttons and the user can guess at which ones apply to
their need and experiment until something works. That is a feature
-- one I personally loathe. To me "easy to use" means having
documentation that includes examples that are close to what
I'm trying to do -- so I can "fill in the blanks" Next there is
the ubiquitously touted "GUI." That's another *feature*. To
me it's of no benefit -- I spend 8 to 16 hours a day looking at
my screen. Text mode screens are far easier on the eyes than
any monitor in graphical mode.
To some people, such as the blind GUI's are a giant step
backward in accessibility. The GUI literally threatens to cut
these people off from vital employment resources.
I'm not saying that the majority of the world should abandon
GUI's just because of a small minority of people who can't
use them and a smaller, crotchety contingent of people like
me that just don't like them. I'm merely trying to point
out the difference between a "feature" and a "benefit."
The "writing wizards" offered by MS Word are another feature
that I eschew. My writing isn't perfect and I make my share
of typos, as well as spelling and grammatical errors. However
Most of what I write goes straight from my fingers to the
recipient -- no proofreading and no editing. When I've
experimented with spell checkers and "fog indexes" I've consistently
found that my discourse is beyond their capabilities -- much too
specialized and involving far too much technical terminology.
So I have to over-ride more than 90% of the "recommendations of
these tools.
Although my examples have highlighted Microsoft products we
can turn this around and talk about Linux' famed "32-bit
power" and "robust stability." These, too are *features*.
Stability is a benefit to someone who manages a server --
particularly a co-located server at a remote location. However
the average desktop applications user could care less about
stability. So long as their application manage to autosave
the last three versions of his/her documents the occasional
reboot is just a good excuse to go get a cup of coffee.
Multi-user is a feature. Most users don't consider this to
be a benefit -- and the idea of sharing "their" system with
others is thoroughly repugnant to most modern computer users.
On top of that the network services features which implement
multi-user access to Linux (and other Unix systems) and NT are
gaping security problems so far as most IS users are concerned.
So having a multi-user system is not a benefit to must of us.
This is particularly true of the shell access that most people
identify as *the* multi-user feature of Unix (as opposed to the
file sharing and multiple user profiles, accounts and passwords
that passes for "multi-user" under Windows for Workgroups and
NT).
So, getting back to ActiveX/DCOM -- I've heard of all sorts
of features. I'd like to hear about some benefits. Keep in
mind that any feature may be a benefit to someone -- so
benefits generally have to be expressed in terms of *who*
is the beneficiary.
Allegedly programmers are the beneficiary of all these
competing component and object schema. "Use our model
and you'll be able to impress your boss with glitzy results
in a fraction of the time it would take to do any programming"
(that seems to be the siren song to seduce people to any of these).
So, who else benefits?
--
Jim
Bash String Manipulations
From: Niles Mills nmills@dnsppp.net
Oddly enough -- while it is easy to redirect the standard error
of processes under bash -- there doesn't seem to be
an easy portable way to explicitly generate message or redirect
output to stderr. The best method I've come up with
is to use the /proc/ filesystem (process table) like so:
function error { echo "$*" > /proc/self/fd/2 }
Hmmmm...how about good old
>&2
?
$ cat example
#!/bin/bash
echo normal
echo error >&2
$ ./example
normal
error
$ ./example > file
error
$ cat ./file
normal
$ bash -version
$ bash -version
bash -version
GNU bash, version 1.14.4(1)
Best Regards,
Niles Mills
I guess that works. I don't know why I couldn't come up
with that on my own. But my comment worked -- a couple of
people piped right up with the answer.
Amigo, that little item dates back to day zero of Unix and
works on all known flavors.
Best of luck in your ventures.
Niles Mills
Blinking Underline Cursor
From: Joseph Hartmann joeh@arakis.sugar-river.net
I know an IBM compatible PC is "capable" of having a blinking
underline cursor, or a blinking block cursor.
My linux system "came" with a blinking underline, which is very
difficult to see. But I have not been able (for the past several
hours) to make *any* headway about finding out how to change the
cursor to a blinking block.
You got me there. I used to know about five lines of
x86 assembly language to call the BIOS routine that sets
the size of your cursor. Of course that wouldn't work under
Linux since the BIOS is mapped out of existence during the
trip into protected mode.
I had a friend who worked with me back at Peter Norton
Computing -- he wrote a toy program that provided an
animated cursor -- and had several need animated sequences
to show with it -- a "steaming coffee cup," a "running man,"
and a "spinning galaxy" are the ones I remember.
If you wanted to do some kernel hacking it looks like
you'd change the value of the "currcons" structure in
one of the /usr/src/linux/drivers/char/ files --
maybe it would be "vga.c"
On the assumption that you are not interested in that
approach (I don't blame you) I've copied the author of
SVGATextMode (a utility for providing text console mode
access to the advanced features of most VGA video cards)
Hopefully Koen doesn't mind the
imposition. Perhaps he can help.
I've also copied Eugene Crosser and Andries Brouwer
the authors of the 'setfont' and 'mapscrn' programs
(which don't seem to do cursors -- but do some cool
console VGA stuff). 'setfont' lets you pick your
text mode console font.
Finally I've copied Thomas Koenig who maintains the
Kernel "WishList" in the hopes that he'll add this as
a possible entry to that.
Any hints?
Best Regards,
Joe,
As you can see I don't feel stumped very often -- and
now that I think about it -- I think this would be a neat
feature for the Linux console. This is especially true since
the people who are most likely to stay away from X Windows are
laptop users -- and those are precisely the people who are
most likely to need this feature.
--
Jim
File Permissions
From: John Gotschall johng@frugal.com
Hi!
I was wondering if anyone there knew how I might actually change the
file permissions on one of my linux box's DOS partition.
I have Netscape running on one box on our local network, but it can't
write to another linux box's MSDOS filesystem, when that filesystem
is NFS mounted. It can write to various Linux directories that have
proper permissions, but the MSDOS directory won't keep a permissions
setting, it keeps it stuck as owned by, read by and execute by root.
What you're bumping into is two different issues.
The default permissions under which a DOS FAT filesystem
is mounted (which is "root.root 755" that is: owned by
user root, group root, rwx for owner, r-x for group and
other).
You can change that with options to the mount (8) command.
Specifically you want to use something like:
mount -t msdos -o uid=??,gid=??,umask=775
... where you pick suitable values for the UID and GID from
your /etc/passwd and /etc/group files (respectively).
The other culprit in this is the default behavior of NFS.
For your own protection NFS defaults to using a feature called
"root squash" (which is not a part of a vegetable). This
prevents someone who has root access to some other system
(as allowed by your /etc/exports file) from accessing your
files with the same permissions as you're own local root account.
If you pick a better set of mount options (and put them in your
/etc/fstab in the fourth field) then you won't have to worry
about this feature. I DO NOT recommend that you over-ride that
setting with the NFS no_root_squash option in the /etc/exports
file (see 'man 5 exports' for details). I personally would
*never* use that option with any export that was mounted
read-only -- not even in my own home between two systems that
have no live connection to the net! (I do use the no_root_squash
option with the read-only option -- but that's a minor risk
in my case).
Is there a way to change the MS-DOS permissions somehow?
Yes. See the mount(8) options for uid=, gid=, and umask=.
I think you can also use the umsdos filesytem type
and effectively change the permissions on your FAT based
filesystem mount points.
This was a source of some confusion for me and I've never
really gotten it straight to my satisfaction. Luckily I find
that I hardly ever use my DOS partitions any more.
Copyright © 1997, James T. Dennis
Published in Issue 19 of the Linux Gazette July 1997
"Linux Gazette...making Linux just a little more fun!"
Adventures in Linux: A Redhat Newbie Boldly Treks Onto the Internet
Frontier
Ever tried using chat to dial out with your modem? If you have, then
after a few hours of mind-numbing inproductivity you may have found
yourself developing an odd, convulsive twitch and banging your head
against your monitor? Another dozen hours of typing in reworded chat
scripts and you will find yourself wishing the program was a living,
tangible entity so you could delete it once and for all out of the known
universe, and thus gain a measure of relief knowing that you have spared
others the terrible ordeal of sitting in front of their monitors for
perhaps days on end coding pleas for chat to just dial the #!%$
telephone. Truthfully, I have found few programs under any of the
operating systems I am familiar with give me the jitters the way chat
does.
I recall one frosty summer morning (I live in Alaska, so I can honestly
describe some summer mornings as being frosty) when I boldly set off
where no Microsoft hacker has gone before-Linux, the final frontier.
Well, that's a bit extreme. Many Microsoft hackers have seen the light
and made the transition. Anyway, I had decided I was going to resist
Bill Gatus of Borg, and not be assimilated, so I put a new hard drive in
my computer, downloaded Redhat Linux 4.1 from Redhat's ftp server (a two
day ordeal with a 33.6 modem, I might add) and read enough of the
install documentation to get started.
Now friends already familiar with the Linux OS offered to come by and
help me set it up. But I'd have none of it. After all, I owned a
computer and electronics service center. I was the expert. And I was
firmly convinced that the best way to truly learn something is to plow
through it yourself. So I sat down in front of my PC with a cup of tea,
made the two required floppy disks for a hard drive install, and began
my voyage into Linux gurudom.
About 45 minutes later I was surprised to discover that I was done.
Linux had been installed on my system and little fishies were swimming
around my monitor in X windows. Well, I was impressed with myself.
"Hah!" I said to the walls. "They said it couldn't be done. Not without
background. Not without experience. But I've showed them. I've showed
them all! Hah! Hah! Hah!" And then, being the compulsive hacker that I
am, I began to do what comes naturally. I hacked. And being the Net buff
that I am, the first thing I decided to do was get on the Internet
through Linux. And all the stuff I'd read about in my printed copy of
the works of the Linux Documentation Project said that the way to dial
out with Linux was through chat.
Four days later I found myself on my knees in front of my computer,
wearily typing in yet another reworded script for chat, half plea, half
incantation, hoping beyond reason that this time chat would perform the
miracle I had so long sought and just dial the $#%! phone. Yes, I was by
that time a broken man. Worse, a broken hacker. My spirit was crushed.
My unique identity was in peril. I could hear Bill Gatus in the
distance, but getting closer, closer, saying, "Resistance is futile. You
will be assimilated." Resigned to my fate, I wrung my hands, achy and
sore from writing enough script variants to fill a novel the size of War
and Peace, and prepared to type halt and reboot into Windows 95.
Then a voice said, "Luke. Luke! Use the X, Luke!" I don't know why the
voice was calling me "Luke" since my name is Cliff, but somehow I knew
to trust that voice. I moved the cursor onto the background, clicked,
and opened up the applications menu. There I found a nifty little
program called Minicom. I clicked on Minicom, it opened, initialized the
modem, and a press of [CTRL-a, d] brought up the dial out options. I
selected the edit option with the arrow keys, and at the top entered the
name and number of my server. Then I selected the dial option with the
arrow keys, and pressed [RETURN]. The X was with me, the modem dialed
out, logged into my server, and with a beep announced that I should
press any button. Minicom then asked me to enter my login name and
password. I breathed a sigh of relief, opened up Arena, typed in an
address, and . . . nothing happened. Worse, after about a minute, the
modem hung up.
"What?" I wondered aloud, squinting into my monitor, certain that behind
the phosphorescent glow I could see little Bill Gatuses frantically
chewing away the inner workings of my computer. "Join me, Cliff," they
were saying. "It is your destiny."
"I'll never join you," I cried out and whipped out my Linux
Encyclopedia. I couldn't find anything in the index on how to avoid
assimilation, but I did find out that I needed to activate the ppp
daemon and give control of the connection from Minicom to the daemon.
The command line that worked best was:
pppd /dev/cua2 115200 -detach crtscts modem defaultroute
-detach
is the most important option to include here. It causes the
daemon to take over control of the modem from Minicom. pppd activates
the Point to Point Protocol daemon. /dev/cua* should be given whatever
number corresponds to the serial port your modem is attached to, as long
as you have a serial modem. 115200 is the max speed of my modem with
compression. You should set this to the max speed of your own modem.
crtscts tells your modem to negotiate high speed transmissions. modem
simply indicates the daemon should use the modem as its means of
networking. It is a default setting, but I like to set it anyway to
remind me whats going on. And defaultroute tells the daemon which route
the incoming and outgoing data are going through.
The trick is to enter all this before the Minicom connection times out.
You could go through the trouble writing it out every time you log on,
but a better way is to edit an alias in .bashrc. Go down to the /root
directory and type emacs .bashrc (or whatever your prefered editor is)
and enter the line below as follows:
alias daemon = <pppd /dev/cua* <your modem speed> -detach crtscts modem
defaultroute>
(Do not forget the quotes or your alias will not function.)
Finally, go into the control panel, double click on the networking icon,
and select the last tab that appears. There you will find near the top
the option to set your default gateway and your device. Set your default
gateway to whatever your Internet server specifies. Specify your device
as /dev/cua (whatever serial port your modem is attached to). Sometimes
simply /dev/modem will work if it has been symbolically linked in your
system. (By the way, if you haven't already done it, in X you also need
to double click the modem icon in the control panel and set your modem
to the correct /dev/cua(serial port number) there too). And if you have
a SLIP account (rare these days) add the pertinent info while setting up
your gateway.
Reboot your system. Now your new alias and settings will all be in
effect. Now just invoke Minicom and dial out. Then at xterminal type
daemon. Minicom will beep at you for taking away its control of the
modem. To be on the safe side, I like to kill Minicom to make sure it
stops fighting with the daemon for control of the modem. Occasionally it
will succeed and weird things will happen. Then invoke your browser and
you are on the World Wide Web.
As a final note, Arena's HTML is kind of weak, and you may find it
locking up with newer, more powerful web code. It is a good idea to
download a more capable browser such as Netscape 3.01, which makes a
fine Linux browser, and install and use that as soon as possible.
And that's all there is to taking your Linux webship onto the
Information frontier. Well, I'm enjoying my time on the web. I think
I'll build a new site dedicated to stopping the assimilation.
Copyright © 1997, Cliff Seruntine
Published in Issue 19 of the Linux Gazette, July 1997
"Linux Gazette...making Linux just a little more fun!"
Atlanta Showcase Report
The Atlanta Linux Showcase
is over, and everyone is beginning to recover.
Recover, that is, from being awake too long, being on a plane too long and
stuffing more Linux than will fit into one weekend.
ALS was put together by the Atlanta Linux Enthusiasts, the local
Linux user's group in Atlanta, Georgia.
The show began on Friday evening, June 6 and ran through Sunday
afternoon.
More than 500 people attended.
The report following this one by Todd Shrider covers much of the show,
including the talks.
I want to thank Amy Ayers and Karen Bushaw for making their photos
available to us with a special thank you to Amy for getting them scanned and
uploaded to the SSC ftp site.
I spent most of my time in the Linux Journal booth giving away
magazines and talking to show attendees.
One aspect that made this show special for me is that I didn't spend
most of my time explaining that Linux is a Unix-like operating system to
the attendees.
Instead, I got to discuss Linux with experienced people with thoughtful
questions, letting them know in the process how LJ could help them.
Each attendee was truly interested in Linux and stopped at each booth in
the show.
I expect attendees appreciated the low signal-to-noise ratio in the
booths; that is, conversations were solely about Linux.
The Roast
On Saturday night there was a roast--no, I didn't change from a
vegetarian into a meat eater overnight--we were roasting Linus.
That is, a group of people presented interesting stories about Linus,
intended to only slightly embarrass him.
At the end of the evening, I felt that the roast had been successful in
every way.
In front of a crowd of about 115 people, Eric Raymond, David Miller, Jon
"maddog" Hall and I got to pick on this Linus character.
Topics varied from Linus almost being hit by a car in Boston because he was
so engrossed in talking about a particular aspect of kernel code, to the evolution of
the top-half/bottom-half concept in interrupt handlers and to why Linus was
apparently moving from geekdom to becoming a "hunk"
sportswear model. (See the cover of the San Jose Metro, May 8-14, 1997.)
Maddog finished the roasting by telling a few Helsinki stories and showing
a video that included Tove's parents talking about Linus.
A good time was had by the roasters and the audience and, as Linus'
closing comment was "I love you all," we assume he had a good
time too and wasn't offended by our gentle ribbing.
The Future
The show came off very well. I consider this sucess an amazing feat for an
all-volunteer effort.
The ALE members plan to write an article for Linux Gazette about how
they made this happen.
We'll also make this information available on the GLUE web site.
I would like to see more shows put on by user groups.
The local involvement, the enthusiasm of the attendees and the all Linux
flavor of the show made this weekend a great experience.
We are already thinking about a Seattle or Portland show and would like to
help others make regional shows a reality.
Take a look at the ALS Photo Album.
More on ALS
by Todd M. Shrider,
todds@ontko.com
I first started writing this article in my hotel room late Sunday evening
(or early Monday morning) planning to get just enough sleep that I would
wake up in time to catch my plane. The plan didn't work--I
missed my 6:00 AM flight out of Atlanta.
I did the second draft while waiting for my new 9:45 AM flight.
The third draft
came (yes, you guessed it) while waiting for my 1:30 PM connection from
Detroit to Dayton, also having missed the previous connection because of
my first flight's late arrival. Suffice it to say, I'm now back home in
Indiana and still enjoying the high received from the Atlanta Linux
Showcase.
Thanks to all the sponsors and to our host, the Atlanta Linux Enthusiasts
user group, the conference started with a bang and went off
without a hitch. The conference was a three day event, starting with
registration Friday and ending Sunday with a kernel hacking session led
by none other than Linus himself. In between there were numerous
conferences found in both a business and technical track, several birds of
a feather (BoF) sessions and a floor show. These events were broken up
with frequent trips to local pubs and very little sleep.
This was my first (but not last) Linux conference, and I found that an
added benefit of ALS was meeting all the people who
use Linux as a viable business platform/tool. (These same people tend to be doing
very cool things with Linux on the side).
From companies such as Red Hat to Caldera to others such as
MessageNet, Cyclades and DCG Computers, it was obvious that many people
have very creative ways to make money with
Linux. This wasn't limited, by any means, to the vendors. Many of the
conference speakers talked of ways to make money with Linux or of their
experiences with Linux in a professional environment.
All of these efforts seemed to compliment the key-note address, World
Domination 101, where Linus Torvalds, called for applications,
applications, applications. Did I say he thought Linux needed a few
more useful applications? Anyway, he pointed out the more or less obvious
fact that, if Linux is going to be a
success in a world of commercial operating systems, we need every
application type you find in other commercial operating systems. In other
words, if you're thinking about doing--don't think--just
do it.
Another thing that Linus pointed out, and that I was glad to hear echoed
throughout the conference, was that Linux needs to be easy to use. It
needs to be so easy that a secretary or corporate executive
could sit and be as productive as they would be
with Windows 95. We need to make people realize that Linux has gotten rid
of the high learning curve usually associated with Unix.
Something pointed out by Don Rosenberg, while speaking on the "how-to" and
"what's needed next" of commercial Linux, was that we are now in a stage
where the innovators (that's us) and the early adopters (that's us as well
as the people using Linux in the business world today) must continue to
push forward so that we can get a group of early adopters (the old DOS
users) to take us seriously. In Maddog's closing remarks he urged us all
to find two DOS users, convert them to Linux and then tell them to do the
same. As a step in this direction, today I introduced a local computer corporate sales
firm to Linux; whether they take my advice and run is left to be seen, but
believe me, I'm pushing.
The rest of the conference was filled with business and technical talks.
The business talks included things such as Eric Raymond's "The Cathedral
and the Bazaar", talks on OpenLinux by both Jeff Farnsworth and Steve
Webb and "Linux Connectivity for Humans" by none other than Phil Hughes.
Lloyd Brodsky was on hand to talk about Intranet Support of Collaborative
Planning while Lester Hightower brought us the story of PCC and their
efforts to bring Linux to the business world. Mark Bolzern spoke of the
significance of Linux and Bob Young talked of the "process" not
the "product" of Linux.
The technical discussion track started with Richard Henderson's discussion
of the shared libraries and their function across several architectures.
Michael Maher gave a HOWTO of Red Hat's RPM package management system and
Jim Paradis discussed EM86 and what remains to be done,
so that one can run Intel/Linux binaries under Alpha
Linux. David Miller then followed giving a boost of enthusiasm with his
discussion of the tasks involved in porting Linux to SPARC and Miguel de
Icaza took us on a trip to the world of RAID and Linux. We convened the next
day to hear David Mandelstam discuss what is involved with wide-area
networks and Mike Warfields anatomy of a cracker's intrusion.
All in all, the conference was a huge success. What I might suggest as an
improvement for next year is more involvement from the vendors (or maybe
just more vendors), a possible sale from the vendors of their special
Linux wares to the conference attendees and a possible tutorial session
like the ones seen at Uselinux (Anaheim, California, January 1997). Other than
that, a few virtual beers (I owe
you Maddog) and lots of great geek conversation made for one wild weekend.
Copyright © 1997, Phil Hughes and Todd M. Shrider
Published in Issue 19 of the Linux Gazette, July 1997
"Linux Gazette...making Linux just a little more fun!"
SSC is expanding Matt Welsh's Linux Installation & Getting
Started by adding chapters about each of the major distributions. Each
chapter is being written by a different author in the Linux community.
Here's a sneak preview--the Caldera chapter by Evan Leibovitch.--editor
Caldera OpenLinux
This section deals with issues specific to the Caldera releases of
Linux, how to install the current release (Caldera OpenLinux) and
prepare for the steps outlined in the following chapters. It is
intended to be a complement to, not a replacement for, the "Getting
Started Guides" Caldera ships with all of its Linux-based
products. References to the Getting Started Guide for Caldera Open
Linux Base will be indicated throughout this chapter simply as "the
Guide".
What is Caldera?
The beginnings of Caldera the company come from an internal Novell
project called "Corsair". While Novell had owned Unix System V in
the early 1990s, Corsair was formed to see if there were things Novell
could learn from Linux.
Corsair was a casualty of the changing of the guard at Novell that
also caused it to sell off Unix to SCO and WordPerfect to
Corel. Novell founder Ray Noorda gave startup capital to this group
with the intention of making Linux available in a manner that would be
as acceptable to business users and corporate MIS as commercial
versions of Unix. Caldera is a privately-held company based in Orem,
Utah.
The implementation of this goal has resulted in a series of
Linux-based products that "broken the mold" in a number of
ways. Caldera was the first Linux distribution to bundle-in commercial
software such as premium X servers, GUI desktops, backup software and
web browsers; at the time of writing, Caldera is the only Linux
distribution officially supported by Netscape.
The Caldera Network Desktop
Caldera's first product, the Caldera Network Desktop (CND), was
released to the public in early 1995 in a $29 "preview" form (a
rather unusual manner to run a beta test), and in final release
version in early 1996. The CND was based on the 1.2.13 Linux kernel,
and included Netscape Navigator, Accelerated-X, CrispLite, and the
Looking Glass GUI desktop. It also was the first Linux release to
offer NetWare client capabilities, being able to share servers and
printers on existing Novell networks. Production and sale of CND
ceased in March 1997.
Caldera OpenLinux
In late 1996, Caldera announced its releases based on the Linux 2.0.25
kernel would be named Caldera Open Linux (COL) and would be made
available at three levels;
- COL Base, which includes Navigator, CrispLite, and the Metro-X server;
- COL Standard, which would add the Netscape FastTrack secure web
server, the StarOffice desktop productivity suite, and NetWare
connectivity;
- COL Deluxe, which incorporates all the features of Standard and
also offers NetWare--server--capabilities.
As this is written, only the COL Base release is shipping,
and feature sets of the other packages are still being determined.
For specific and up-to-date lists of the comparative features of the
three levels, check the Caldera web site http://www.caldera.com.
Because all three levels of COL build on the Base release, all three
are installed the same way. The only difference is in the different
auxiliary packages available; their installation and configuration
issues are beyond the scope of this guide. Most of COL's add-on
packages contain their own documentation; check the /doc directory of
the Caldera CD-ROM for more details.
Obtaining Caldera
Unlike most other Linux distributions, COL is not available for
downloading from the Internet, nor can it be distributed freely or
passed around. This is because of the commercial packages which are
part of COL; while most of the components of COL are under the GNU
Public License, the commercial components, such as Looking Glass and
Metro-X, are not. In the list of packages included on the COL media
starting on page 196 of the Guide, the commercial packages are noted
by an asterisk.
COL is available directly from Caldera, or through a network of
Partners around the world who have committed to supporting Caldera
products. These Partners can usually provide professional assistance,
configuration and training for Caldera users. For a current list of
Partners, check the Caldera web site.
Preparing to Install Caldera Open Linux
Caldera support the same hardware as any other release based on Linux
2.0 kernels. Appendix A of the Guide (p145) lists most of the SCSI
hosts supported and configuration parameters necessary for many
hardware combinations.
Taking a page out of the Novell manual style, Caldera's Guide provides
an installation worksheet (page 2) that assists you in having at hand
all the details of your system that you'll need for installation. It
is highly recommended you complete this before starting installation;
while some parameters, such as setting up your network, are not
required for installation, doing it all at one time is usually far
easier than having to come back to it. Sometimes this can't be
avoided, but do as much at installation time as possible.
Creating boot/modules floppies
The COL distribution does not come with the floppy disks required for
installation. There are two floppies involved; one is used for
booting, the other is a "modules" disk which contains many hardware
drivers.
While the Guide recommends you create the floppies by copying them
from the CD-ROM, it is better to get newer versions of the disks from
the Caldera web site. The floppy images on some CD-ROMs have errors
that cause problems, especially with installations using SCSI disks
and large partitions.
To get newer versions of the floppy images, download them from
Caldera's FTP site. In directory {\tt pub/col-1.0/updates/Helsinki}, you'll
find a bunch of numbered directories. Check out the directories in
descending order---that will make sure you get the latest versions.
If you find one of these directories has a subdirectory called
bootdisk
, the contents of that directory
are what you want.
You should find two files:
install-2.0.25-XXX.img
modules-2.0.25-XXX.img
The
XXX
is replaced by the version number of the disk images.
At the time of writing, the current images are 034 and located in the
001 directory.
Once you have these images, transfer them onto two floppies using the
methods described on page 4 of the Guide, using RAWRITE from the
Caldera CD-ROM if copying from a DOS/Windows system or
dd
from a Linux system.
While Caldera's CD-ROM is bootable (if your system's BIOS allows it),
if possible use the downloaded floppies anyway, since they are newer
and will contain bug-fixes that won't be in the CD versions.
Preparing the hard disks
This procedure is no different from that of other Linux distributions.
You must use fdisk on your booted hard disk to allocate at least two
Linux partitions, one for the swap area and one for the root
file system. If you are planning to make your system dual-boot COL
with another operating system such as MS Windows or DOS or even OS/2,
it's usually preferable to install COL last; its "fdisk" recognizes
"foreign" OS types better than the disk partitioning tools of most
other operating systems.
To run the Linux fdisk, you'll need to start your system using the
boot (and maybe the modules) floppy mentioned above. That's because
you need to tell COL what kind of disk and disk controller you have;
you can't even get as far as entering
fdisk
if Linux doesn't
recognize your hard disk!
To do this, follow the bootup instructions in the Guide, from step 2
on page 33 to the end of page 36. Don't bother going through the
installation or detection of CDROMs or network cards at this time; all
that matters at this point is Linux sees the booting hard disk so you
can partition it using fdisk. A brief description of the use of the
Linux fdisk is provided on page 28 of the Guide.
Remember that when running fdisk, you need to set up both your root
file system (type 83) and your swap space (type 82) as new partitions.
A brief discussion of how much swap space to allocate is offered on
page 10 of the Guide.
As soon as you have completed this and written the partition table
information to make it permanent, you will need to reboot.
Copyright © 1997, Evan Leibovitch
Published in Issue 19 of the Linux Gazette, July 1997
"Linux Gazette...making Linux just a little more fun!"
CLUELESS at the Prompt: A new column for new users
by Mike List,
troll@net-link.net
Welcome to installment 6 of Clueless at the Prompt:
a new column for new users.
This time let's take a quick look at
the XF86Setup utility. at X window managers, concentrating on FVWM, adding
popup menus, adding and subtracting apps from existing popups and other
relatively easy ways to get a custom appearance and feel.
Using XF86Setup to configure X
Judging from the posts I've seen on the usenet, a lot of people aren't
aware that there's an easier way to get X up and running than configuring
it the old confusing way(at least I found it to be that way), using a
tcl/tk script called XF86Setup. While it doesn't totally eliminate the
need to manually edit your XConfig, it does provide a method of getting a
usable configuration for most common video cards and monitors. XF86Setup
first appeared in the XFree86 3.2 distribution, and uses the lowest common
denominator VGA 16 color mode server and a tcl/tk(corrections welcome)
script to start the config process in X and by using the graphical nature
of this utility script you can be almost certain to have X running in a
couple of tries, and if worst comes to worst you can have it running in 16
color mode until you can get the details to optimize it to your video
hardware. Current downloads of Xfree86 all seem to have this included, and
if your CDROM diskribution has X 3.2 or better you already have it
available to install to your HD. If you download it from xf86.org, be sure
to read the Relnotes for the component files necessary to insure a
successful install. You'll need :
- preinst.sh Pre-installation script
- postinst.sh Post-installation script
- X3?bin.tgz Clients, run-time libs, and app-defaults files
- X3?doc.tgz Documentation
- X3?fnts.tgz 75dpi, misc and PEX fonts
- X3?lib.tgz Data files required at run-time
- X3?man.tgz Manual pages
- X3?set.tgz XF86Setup utility
- X3?VG16.tgz 16 colour VGA server (XF86Setup needs this
server)
, where ?=the level of the distribution you're using, ie.3.2,
3.3 etc.,
for all installations, read the relnotes for any oher files your specific
hardware might need.
Since the 3.3 version just came out, if you are just getting around to
setting up X you will most likely want to get this distribution, since
every successive version has support for more hardware and often better
support for hardware already supported.
OK, you have the files you need, that is the ones listed above, and the
server for your particular video card, in my case the SVGA server, you may
need to do a little detective work to determine which server to use.
If you are using the X version that comes on your CDROM, you can probably
install all the servers(assuming there's space on your HD)and let the
XF86Setup prog make the choice. To install,type:
cd /usr/X11R6
Next, copy the preinst.sh and postinst.sh scripts to /var/tmp, then go to
/usr/X11R6 and type:
cd /usr/X11R6
sh /var/tmp/preinst.sh
the script will remove some symbolic links, and check to see that all the
files you need are available, and may output a message asking for those
files that are needed but not present. But assuming that you have followed
the above, everything should be in place, and you should get a generally
encouraging message on exit from the script.
Now for the installation itself,type:
tar -zxvf /wherever/you/have/X3?files.tgz
you'll have to repeat this step with each of the required files, although
if you have these files in a directory by themselves, you may be able
to type:
tar -zxvf /wherever/youhavethem/*.tgz
although it's been awhile, and I can't recall if it works, it won't hurt
anything to try, since the alternative is to unpack each tgz file
separately.
Next you run the postinst.sh script in the same manner as the
preinst.sh above, this will make sure that you have all the X components
in the correct places.Run ldconfig something like:
ldconfig -m /usr/X11R6/lib
or reboot to run ldconfig automatically. This links the libraries
necessary to run X. At this point you should be able to start the actual
setup by typing, naturally:
XF86Setup
which will present a dialog box asking if you want to start in graphical
mode or tell you it will start momentarily.
At this point you'll be in X, using the 16 color VGA server.Read all the
instructions, and follow the routine, which I found to be pretty
self-explanatory. You will probably have the most trouble finding the
right mouse device and protocol, but try each one in turn if you aren't
sure. You'll probably also want to change the keyboard to 102key US
International keyboard. Specify the video card, and monitor info, don't
worry if you don't know the salient monitor inf, you cna start at the top
of the list and work your way down the list until you reach a good
setting.Much easier if you have your monitor manual available, so have it
on hand if you can. Finish the routine when you think it's right and that
should do it. Congratulations on your hopefully valid Xconfiguration. If
you muff it just try again using slightly different settings until you do
get it right.
Window Managers
Most Linux distributions that i'm familiar with use the FVWM window
manager as default and the rest of them should have it present, unless you
downloaded the files directly from xf86.org, in which case the default is
TWM.
FVWM is highly configurable by editing the
/var/X11R6/lib/fvwm/system.fvwmrc file.You can use the file as it is,
since it has the most common installed features already configured, but
you can comment out those programs that you don't have installed by adding
a "#" at the beginning of the lines you wish to drop, change colors, add
popup menus, and more just by following the examples. Just be sure to save
the system.fvwmrc by typing:
cp /var/X11R6/lib/fvwm/system.fvwmrc
/var/X11R6/lib/fvwm/system.fvwmrc.old
or something similar, so if you do mess up on your customization you can
always start from scratch by cp'ing .old to the original system.fvwmrc.A
couple of months ago The Weekend Mechanic column had some very cool ideas
on wallpapering the root window, so you might want to check them out.
I made "Internet" and "PPP" popup menus to include lynx, Netscape and a
couple of telnet sites, as well as an IRC client, and to use the chat
script from X. you may have other ideas more to your liking, don't be
afraid to try, you can always start over again if you don't like the
results.
Take a look at my system.fvwmrc, nothing too
sophisticated, but if you compare it to the original you should get the
idea. I commented the changes that I made so you can see some of the
ways in which you can customize yours.
Copyright © 1997, Mike List
Published in Issue 19 of the Linux Gazette, July 1997
"Linux Gazette...making Linux just a little more fun!"
Graphics Muse
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Set your browser to the width of the line below for best viewing.
© 1997 by
mjh
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muse:
- v; to become absorbed in thought
- n; [ fr. Any of the nine sister goddesses of learning and the
arts in Greek Mythology ]: a source of inspiration
 elcome
to the Graphics Muse! Why a "muse"?
Well, except for the sisters aspect, the above definitions are
pretty much the way I'd describe my own interest in computer graphics:
it keeps me deep in thought and it is a daily source of inspiration.
[Graphics Mews]
[Musings]
[Resources]
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column is dedicated to the use, creation, distribution, and discussion of
computer graphics tools for Linux systems.
This month has been even more hectic than most. I finished the first
pass of an article on the 1.0 release of the GIMP and submitted it to the
LInux Journal editors. That will be out in the November Graphics issue.
I'll probably have to do some updates after I get back the marked up
version. I'm also working on the cover art for that issue, using the
developers release (currently at 0.99.10) of the GIMP. I've also had
quite of bit of regular work (that kind that pays the rent) since I'm
getting very close to my code freeze date. This weekend I'll be writing up
documentation for it so I can give an introductory class to testers, other
developers, Tech Pubs, Tech Support, and Marketing on Monday. I think I
picked a bad time to start lifting weights again.
In this months column I'll be covering ...
- More experiences with printing using the Epson Stylus Colro 500
- A brief discussion about DPI, LPI, and Halftoning
- An even briefer discussion about 3:2 pulldown - transerring film
to video.
Next month may not be much better. I don't know exactly what I'll be
writing about, although I do have a wide list from which to choose. Mostly
I'm looking forward to my trip to SIGGRAPH in August. Any one else going?
I should have plenty to talk about after that. I plan on going to at
least two of the OpenGL courses being taught at the Conference. I haven't
completely decided which courses I'm going to take, however.
I'm also looking forward to a trip to DC in August as well. A real
vacation. No computers. Just museums and monuments. I may need to take
some sort of anti-depressant. Nah. I need the break.
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Disclaimer:
Before I get too far into this I should note that any of the news items I
post in this section are just that - news. Either I happened to run
across
them via some mailing list I was on, via some Usenet newsgroup, or via
email from someone. I'm not necessarily endorsing these products (some of
which may be commercial), I'm just letting you know I'd heard about
them in the past month.
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Announcing bttv version 0.4.0
BTTV is a device driver for Booktree Bt848 based frame grabber cards
like the
Hauppauge Win/TV pci, Miro PCTV, STB TV PCI, Diamond DTV2000, and
AverMedia. Major new features in version 0.4.0 are rudimentary
support for grabbing into user memory and for decoding VBI data
like teletext, VPS, etc. in software.
The Motif application xtvscreen now has better support for selecting
channels and also works in the dual visual modes (255+24 mil. colors)
of Xi Graphics AcceleratedX 3.1 X server.
Author:
Ralph Metzler
rjkm@thp.uni-koeln.de
Marcus Metzler
mocm@thp.uni-koeln.de
Web Site:
http://www.thp.uni-koeln.de/~rjkm/linux/bttv.html
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OpenGL4Java 0.3
This is an initial developer's release of an (unoffical) port of
OpenGL(tm) for java. Leo Chan's original package has been
ported to both WindowsNT/95 and to Linux.
Several features have been added, the main
one being OpenGl now draws into a Java Frame.
What advantage does this provide? Well, you can now add menus
to the OpenGL widget as well as receiving all normal events such
as MouseMotion and Window events. You
could very simply have a user rotate a OpenGL object by moving the mouse
around in the Frame ( the demo for the next release will have this
feature ).
You can grab it from the developers web page at
http://www.magma.ca/~aking/java.
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WebMagick Image Web Generator - Version 1.29
WebMagick is a package which makes putting images on the Web as
easy as magick. You want WebMagick if you:
- Have access to a Unix system
- Have a collection of images you want to put on the Web
- Are tired of editing page after page of HTML by hand
- Want to generate sophisticated pages to showcase your images
- Want to be in control
- Are not afraid of installing sophisticated software packages
- Want to use well-documented software (33 page manual!)
- Support free software
After nine months of development, WebMagick is chock-full of
features. WebMagick recurses through directory trees, building
HTML pages, imagemap files, and client-side/server-side maps to
allow the user to navigate through collections of thumbnail
images (somewhat similar to xv's Visual Schnauzer) and select
the image to view with a mouse click. In fact, WebMagick
supports xv's thumbnail cache format so it can be used in
conjunction with xv.
The primary focus of WebMagick is performance. Image thumbnails
are reduced and composed into a single image to reduce client
accesses, reducing server load and improving client performance.
Everything is pre-computed. During operation WebMagick employs
innovative caching and work-avoidance techniques to make
successive executions much faster. WebMagick has been
successfully executed on directory trees containing many tens of
directories and thousands of images ranging from tiny icons to
large JPEGs or PDF files.
Here is a small sampling of the image formats that WebMagick
supports:
- Windows Bitmap image (BMP)
- Postscript (PS)
- Encapsulated Postscript (EPS)
- Acrobat (PDF)
- JPEG
- GIF (including animations)
- PNG
- MPEG
- TIFF
- Photo CD
WebMagick is written in PERL and requires the ImageMagick (3.8.4
or later) and PerlMagick (1.0.3 or later) packages as well as a
recent version of PERL 5 (5.002 or later). Installation
instructions are provided in the WebMagick distribution.
Obtain WebMagick from the WebMagick page at
http://www.cyberramp.net/~bfriesen/webmagick/dist/.
WebMagick
can also be obtained from the ImageMagick distribution site at
ftp://ftp.wizards.dupont.com/pub/ImageMagick/perl.
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EasternGraphics announces public release of `opengl' widget
EasternGraphics announces the public release of `opengl' widget
which allows windows with three-dimensional graphics output,
produced by OpenGL to be integrated into Tk applications. The
widget is available for Unix and MS-Windows platforms.
You can download the package from
ftp://ftp.EasternGraphics.com/
pub/egr/tkopengl/tkopengl1.0.tar.gz
Email:
wicht@EasternGraphics.com
WWW:
http://www.EasternGraphics.com/
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ELECTROGIG's GIG 3DGO 3.2 for Linux for $99.
There is a free demo package for Linux. Its roughly 36M tarred
and compressed. A 9M demo's file is also available for download.
I had placed a notice about this package in the May's Muse column,
but I guess ELECTROGIG had missed that, so they sent me another
announcement (I got the first one from comp.os.linux.announce).
Anyway, one thing I didn't mention in May was the price for the
full Linux product: $99. This is the complete product, although
I'm not sure if this includes any documentation or not (it doesn't
appear to). The Linux version does not come with any product
support, however. You need a 2.0 Linux kernel to run GIG 3DGO.
I also gave a URL that takes you to an FTP site for downloading the
demo. A slightly more informative page for downloading the demo and
its associated files is at
http://www.gig.nl/support/indexftp.html
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Type1Inst updated
James Macnicol
uploaded version 0.5b of his type1inst font installation utility
to sunsite.unc.edu. If its not already there, it will end up in
/pub/Linux/X11/xutils.
Type1inst is a small perl script which generates the
"fonts.scale" file required by an X11 server to use any
Type 1 PostScript fonts which exist in a particular
directory. It gathers this informatiom from the font files
themselves, a task which previously was done by hand. The
script is also capable of generating the similar "Fontmap"
file used by ghostscript. It can also generate sample sheets
for the fonts.
FTP:
ftp://sunsite.unc.edu/pub/Linux/X11/xutils/type1inst-0.5b.tar.gz
Editors note: I highly recommend this little utility if you
are intent on doing any graphics arts style work, such as with
the GIMP.
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libgr-2.0.13 has been updated to png-0.96
It seems the interface to
png-0.96 is not binary compatible with png-0.89, so the major
version of the shared library was bumped to libpng.so.2.0.96
(last version was libpng.so.1.0.89).
WHAT IS LIBGR?
Libgr is a collection of graphics libraries,
based on libgr-1.3, by Rob Hooft (hooft@EMBL-Heidelberg.DE),
that includes:
- fbm
- jpeg
- pbm
- pgm
- png
- pnm
- ppm
- rle
- tiff
- zlib, for compression
These are configured to build ELF static and shared libraries.
This collection (libgr2) is being maintained by
Neal Becker <neal@ctd.comsat.com>
FTP:
ftp.ctd.comsat.com:/pub/linux/ELF
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Did You Know?
...there is a site devoted to settign up Wacom tablets under XFree86?
http://www.dorsai.org/~stasic/wacomx.htm
The pages maintainer,
Edward, says:
So far, nobody has told me that he or she couldn't follow the
instructions.
Fred Lepied is the man who actually created the support for the
Wacom tablets under XFree86. He gave me instructions on setting
my ArtPad II up and I repeated this, periodically, on Usenet.
When the requests for help there turned into a steady stream,
I decided to put up a web page (mainly to show that I can make
one but not use it for a lame ego trip).
Adam D. Moss
<adam@uunet.pipex.com> has said he's also gotten this to work
and offered to help others who might need assistance getting
things set up.
...there is rumored work being done on 3Dfx support for Linux?
Tige writes:
I was looking around for info about the 3Dfx based cards and came across
a guy's page that said he is working on a full OpenGl driver for 3Dfx
boards for NT. What does this have to do with Linux? Well, he says
that after the NT driver is done, he is going to start work on 3Dfx
drivers for Linux and an OpenGl driver for XFree86/3Dfx.
The guy's name is Zanshin and the address of his site is:
http://www.planetquake.com/gldojo/
Most of this stuff is in the News Archives section under 4/18/97
Oh yeah, he also mentions hacking SGIQuake to work with Linux, so we may
get to see a hardware accelerated version of Quake for Linux.
...the MindsEye Developers mailing list has moved to
mindseye@luna.nl.
unsubscribing can be done by sending a body of
unsubscribe
to
mindseye-request@luna.nl
and a body of
unsubscribe mindseye@luna.nl
to
majordomo@luna.nl
Other majordomo commands should be send to majordomo@luna.nl
a body of 'help' gives an overview.
Users which are subscribed to the old mindseye@ronix.ptf.hro.nl adress
do not need to unsubscribe. The list will be removed shortly afterwards.
They will get this message twice: one from mindseye@luna.nl and one from
mindseye@ronix.ptf.hro.nl.
A HTML interface by using hypermail is under construction.
Q and A
Q:
Forgive what might be a dumb question, but what exactly is meant by
"overlays"?
A:
Imagine a 24bpp image plane, that can be addressed by 24bpp visuals.
Imagine an 8bpp plane in front of the 24bpp image plane, addressed by
8bpp visuals.
One or more of the 8bpp visuals, preferably the default visual, should
offer a 'transparent pixel' index. When the 8bpp image plane is painted
with the transparent pixel, you can see through to the 24bpp plane.
You can call an arrangement like this, a 24bpp underlay, or refer to the
8bpp visuals as an overlay.
Strictly, we call this "multiple concurrent visuals with different color
depths", but that's rather a mouthful. Hence, shorthand we refer to it
as "24+8" or "overlays", with "24+8" as the preferred description.
From Jeremy Chatfield @ Xi Graphics, Inc.
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Microstation update
After last months 3D Modeller update I received email
from Mark Hamstra at Bentley Systems, Inc. Mark is the man
responsible for the ports of Bentley's MicroStation and Masterpiece
products that are available for Linux. I've included his response
below. The stuff in italics is what I had orginally written:
Thanks for the mention in Gazette #18 --it's kinda fun watching where
MicroStation/Linux info pops up. Being the guy that actually did the
ports of MicroStation and Masterpiece, I'll lay claim to knowing the most
about these products. Unfortunately, you've got a few errors in Gazette
#18; allow me to correct them:
Includes programming support with a BASIC language and linkages
to various commericial databases such as Oracle and Informix.
Programming support in the current product includes the MicroStation
Development Language (C syntax code that compiles to platform-independent
byte-code), BASIC, and support for linking MDL with both MDL shared
libraries and native code shared libraries (i.e., Linux .so ELF
libraries). For a look at the future direction of Bentley and
MicroStation, take a look on our web site at the recent announcement by
Keith Bentley at the AEC Systems tradeshow of MicroStation/J and our
licensing agreement with Javasoft.
Because of the lack of commercial database support for Linux, there are
no database linkage facilities in the current Linux port of MicroStation.
This looks like the place to go for a commercial modeller, although
I'm not certain if they'll sell their educational products to the
general public or not.
Nope, academic-only at this time; although we're collecting requests for
commercial licensing (at our normal commercial prices) at
http://www.bentley.com/products/change-request.html.
The only thing preventing MicroStation from being available
commercially for Linux is a lack of adequate expressed interest.
Note that the Linux ports have not been released (to my knowledge - I'm
going by whats on the web pages).
The first two of our new Engineering Academic Suites that contain the
Linux ports, the Building Engineering and GeoEngineering Suites, have been
available in North America since the middle of February. European and
worldwide distribution should be underway now too, although it took a
little longer. Incidentally, the web pages you list are for our Europe,
Middle East, and Africa (ema) division; you probably actually want
http://www.bentley.com/academic.
[output formats] Unknown
We output a wide range of formats (and import a wider range than you give
us credit for). I always forget just which ones are actually in the
product and which are only in my current builds from the most recent
source, so I'll just refer you to
http://www.bentley.com/products/microstation95 and
http://www.bentley.com/products/masterpiece, and note that my copy of
MicroStation/Linux currently lists DGN, DWG, DXF, IGES, CGM, SVF, GRD,
RIB, VRML, Postscript, HPGL, PCL, TIFF, TGA, BMP, and a couple other
raster and animation formats as output options -- and I know I haven't
currently got some of our soon-to-be-released translators compiled. Like
I said, probably not all of these are in the current Linux port, but it's
a simple matter to add whatever's not there to future versions of the
Linux products, provided there's enough demand to keep the project
going.
I wasn't sure what a few of these formats were, so I wrote Mark back
to ask about them. He informed me on the following (which were the ones I
had asked specifically about):
- DGN is MicroStation-native design file format and
has its ancestry in the Intergraph IGDS file format.
- SVF is the Simple Vector Format (see
http://www.softsource.com),
which works pretty good for web browser plug-ins.
- GRD is used by our MicroStation Field product.
- CGM is the Computer Graphics Metafile format, a
vendor-independent standard supported in various software
packages, browser plug-ins, printers/plotters, etc.
I want to thank Mark for offering updated information so quickly. My
information is only as good as what I can find or am fed, and it helps
when vendors, developers or end users provide me with useful info like
this. Many thanks Mark.
If you've used this product on MS platforms feel free to drop me a
line and let me know what you thought of it. I'm always out to support
commercial ports of graphics-related products to Linux.
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Printing with an Epson Stylus Color 500
I bought an Epson Stylus Color 500 printer back in December of last year
so I could print in color. I had done some
research into what printers would be best,
based in part on reviews in online PC magazines
and also on support available in the Ghostscript 4.03 package. The
Epson Stylus Color 500 was rated very high by the reviews and I found a
web page
which provided information on how to configure Ghostscript
for use with the printer. I bought the printer, got Ghostscript
working in a very marginal way (that is to say, it printed straight
text in black and white). But thats as far as it went. I had gotten
some minor printing in color done, but nothing very impressive and
most of it was downright bad.
Earlier this month I was given the opportunity to work on the cover
art for an issue of the Linux Journal. A few trial runs were given
the preliminary ok but they were too small - the size of the image
needed to be more than twice as big as the original I had created.
Also, because the conversion of an image from the monitors display to
printed paper is not a straightforward one (see the discussion on
LPI/DPI elsewhere in this months column) it became apparent I needed
to try printing my artwork to sample how it would really look on paper.
I had to get my printer configuration working properly.
Well, it turned out to be easier than I thought. The hardest part
is to get Ghostscript compiled properly. The first thing to do is
to be sure to read the text files that accompany the source code.
There are 3 files to read:
- make.txt - general compiling and installation instructions
- drivers.txt - configuration information for support of the
various devices you'll need for your system.
- unix-lpr.txt - help on setting up a print spooler for Unix
systems.
The first two are the ones that made the most difference to me. I
didn't really use the latter, but my solution isn't very elegant.
However, what it lacks in grace it makes up for in simplicity.
Building the drivers was fairly simple for me - I took most of the
defaults, except I added support for the Epson Stylus Color printers.
There is a section in make.txt devoted specifically to compiling on
Unix systems (search for How to build Ghostscript from source
(Unix version) in that file). In most cases you'll just be able
to type "make" after linking the correct compiler specific makefile
to makefile. However, I needed to configure in the Epson
printers first.
What I did was to edit the unix-gcc.mak file
to change one line. The line that begins
DEVICE_DEVS=
was modified to add
stcolor.dev
right after the equal sign. I also didn't need support for
any of the HP DeskJet (DEVICE_DEVS3 and DEVICE_DEVS4) or
Bubble Jet (DEVICE_DEVS6) devices so I commented out those lines.
Now, once this file had been linked to makefile I could just
run
make
make install
At this point the Ghostsript package was ready for use. Note that
many of the current distributions already include Ghostscript, but may not
have the 4.03 release. Run
gs -v
to find out if you have Ghostscript 4.03. You'll need it to work
with the Epson Stylus Color 500.
Now I needed to set up my print spooler. This turned out to be
rather easy. First, you need to know that the stcolor driver
(which is the name of the driver Ghostscript uses to talk to
Epson Stylus printers) has a pre-built Postscript file that is
used to prepare the printer for printing. This file, called
stcolor.ps, is included with the 4.03 distribution. The file
contains special commands that are interpreted by the printer,
however it does not actually cause anything to be printed.
-Top of next column-
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When you
want to print something you need to first print this file followed
by the file or files you want to print. Don't worry about how to
do this just yet - I have a set of scripts to make this easier.
There were a number of options I could use with Ghostscript for
my printer, but I found I only needed to work with one: display
resolution or Dots Per Inch (DPI). In order to handle the two
resolutions I simply created two scripts which could be used as
input filters for lpr (the print spooler). The
scripts
are almost
exactly the same, except one is called stcolor and one
is called stcolor-high, the latter being for the higher
resolution. Both of these were installed under
/var/spool/lpd/lp and given execute permissions.
Next came the configuration for lpr. I needed to edit the
/etc/printcap
file to create entries for the new printer filters.
I decided to give the printers different names than the standard,
non-filtered printer name. In this way I could print ordinary
text files (which I do more than anything else) using the default
printer and use the other printer names for various draft or
final prints of images, like the cover art.
Now the system was ready to print my images, but I still needed
to do a couple more things. First, I wanted to write a script
for handling printing of my images in the most common formats
I created. I wrote a
script
to do this which I named print-tga.sh. I made symbollic
links from this file to variations on the name. The script
uses the name used to invoke it to determine which type of
conversions to run before printing the file.
The script converts the various formats, using the tools in
the NetPBM kit, to Postscript files and then prints them to the
high resolution printer setup in the previously mentioned printcap
file.
Once I got all this done I was able to print full page images
on high-gloss paper. They come out beautifully. The images I
created for the cover art are far bigger than the paper, so Ghostscript
resizes them to fit. It wasn't until I got this working that I
realized just how good Ghostscript is. Or just how good the Epson
Stylus Color 500 is.
As a side bonus, I also discovered that I could now print pages
from my Netscape browser to my printer. I configured the
print command to be lpr -llpps (using the lower resolution
printer from the /etc/printcap file) in the Print dialog. Since
Netscape passes the page as a Postscript file to the filter, there
is no need to do any conversions like I do with my images. I now
get full color prints of the pages I wish to save (like SIGGRAPH's
registration forms). I also can print directly from Applixware
using the same printer configurations. I just had to set up the
print options to output as Postscript, which was simply enough to do.
There are a number of other settings that can be set using the
filters. If you are interested in using these you should consult the
devices.txt file for information on the stcolor driver. There are
probably some better settings than what I'm using for other types of
printing needs.
Well, thats about it. I hope this was of some use to you. I was
really thankful when I got it working. My setup is probably not
exactly like anyone elses, but if you have the Epson Stylus Color
500 you should be able to get similar results. Don't forget: if
you plan on printing high resolution images using the 360 DPI (as
opposed to the 180 DPI also supported by the printer) then you'll
probably want to print on high-gloss paper. This paper can be rather
expensive. The high-gloss paper Epson sells specifically for this
printer is about $36US for 15 sheets. Also, I should note that
I recently heard Epson now has a a model 600 that is to replace
the model 500 as their entry level color printer. I haven't
heard if the 600 will work with the stcolor driver in Ghostscript
so you may want to contact the drivers author (who is listed
in the devices.txt file, along with a web site for more info) if
you plan on getting the model 600.
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The following links are just starting points for finding more information
about computer graphics and multimedia in general for Linux systems. If
you have some application specific information for me, I'll add them to my
other pages or you can contact the maintainer of some other web site. I'll
consider adding other general references here, but application or site
specific information needs to go into one of the following general
references and not listed here.
Linux Graphics mini-Howto
Unix Graphics Utilities
Linux Multimedia Page
Some of the Mailing Lists and Newsgroups I keep an eye on and where I get alot
of the information in this column:
The Gimp User and Gimp Developer Mailing Lists.
The IRTC-L discussion list
comp.graphics.rendering.raytracing
comp.graphics.rendering.renderman
comp.graphics.api.opengl
comp.os.linux.announce
Future Directions
Next month:
I have no idea. I have a ton of things that need doing, but I just
haven't had time to figure out what I *should* do. I still have part 3 of
the BMRT series to do, which I plan on doing as part of the process of
creating an animation. The animation is another topic I'd like to do.
I've also had requests for a number of other topics. One good one was to
cover the various Image Libraries that are available (libgr or its
individual components, for example). I have a review of Image Alchemy to
do (long ago promised and still not done *sigh*). Well, at least I'll
never be short a topic.
Let me know what you'd like to hear about!
Copyright © 1997, Michael J. Hammel
Published in Issue 19 of the Linux Gazette, July 1997
Graphics Muse
More...
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Raster images are always discussed in terms of pixels, the
number of dots on the screen that make up the height and width of the
image. As long as the image remains on the computer there is no need to
worry about converting this to some other resolution using some other
terminology. Pixel dimensions work well for Web pages, for example.
The reality is that many images aren't very useful if they remain on the
computer. Their real usefulness lies in their transfer to film, video tape or
printed paper such as magazines or posters. The trouble with this is that
printing an image is much different than simply viewing it on the screen.
There are problems related to color conversions (RGB to CMYK), for example.
We'll have to deal with that some other time (like when I learn something
about it). Printing also requires a different set of dimensions
because of the way they work. Printed images are handled by the number of
Dots Per Inch that the printer can handle. In order to get the image to
look the way you want it on the printer, you'll need to understand how
printers work.
First, some background information:
- Printer resolution is given in dots per inch (DPI). That is the number
of dots the device can output in an inch.
-
Lines per inch (LPI) relates to halftoning. Many devices (such as
printers) only have bilevel channels, that is, either they paint a
colored dot or they don't (there are no smooth steps). Halftoning
means using different patterns of dots to simulate a greater
number of color shades. Obviously, several dots must be used in
certain on/off combinations to simulate having more shades.
LPI comes from the world of photography while DPI comes from the world of
design. Whether it makes sense to speak of DPI resolution for a raster image
depends on what you'll be using that image for. Most magazines, such as
Time, are printed with 153 LPI or less. Newspapers such as the Wall Street
Journal are printed at 45-120 LPI.
Halftoning masks are the patterns used to create the shades of color
or levels of gray seen in the lines per inch on the printed media.
Most masks are square. Let's say you have a printer which can do 300 DPI,
that is, it can print 300 dots in an inch. If the halftoning mask is
4 pixels wide, then you'll have 300/4 = 75 lines per inch (LPI) for
the halftones. That is the effective resolution of the device, since
you are interested in nice shaded printouts and not in single bilevel
dots.
An ultra-expensive 1200 DPI typesetter will be able to do 300 LPI if
you use 4-pixel wide halftone masks. Of course, the larger the
halftone size, the more shades you'll get, but the lower the effective
resolution will be.
If you are only going to display an image on your screen, then perhaps
speaking of DPIs in the image is pointless. You'll be mapping one
pixel in the image to one pixel on your display, so how physically
big the image looks will depend only on the size of your monitor.
This makes sense; when you create images for display on a monitor, you
usually only think in terms of available screen space (in pixels), not
about final physical displayed size. I.e. when you create a web page
you try to make your images so that they'll fit on the browser's
window, regardless of the size of your monitor.
The story is a bit different when you are creating images for output
on a hardcopy device. You see, sheets of paper have definite physical
sizes and people do care about them. That's why everyone tries to
print Letter-sized documents on A4 paper and vice-versa.
The simplest thing to do is to just create images considering the
physical output resolution of your printer. Let's say you have a 300
DPI printer and you create an image which is 900 pixels wide. If you
map one image pixel to one device pixel (or dot), you'll get a 3-inch wide
image:
900 pixels in image / 300 dots per inch for printing = 3 inches of image.
That sucks, because most likely your printer uses bilevel dots and
you'll get very ugly results if you print a photograph with one image
pixel mapped to one device pixel. You can get only so many color
combinations for a single dot on your printer --- if it uses three
inks, Cyan/Magenta/Yellow (CMY) and if it uses bilevel dots (spit ink
or do not spit ink, and that's it), you'll only be able to get a
maximum of 2*2*2 = 8 colors on that printer. Obviously 8 colors is
not enough for a photograph.
So you decide to do the Right Thing and use halftoning. A halftone
block is usually a small square of pixels which sets different
dot patterns depending on which shade you want to create.
Let's say you use 4-pixel square halftones like in the previous
paragraphs. If you map one image pixel to one halftone block, then
your printed image will be four times as large as if you had simply
mapped one image pixel to one printer dot.
A good rule of thumb for deciding at what size to create images is the
following. Take the number of lines per inch (LPI) that your printer
or printing software will use, that is, the number of halftone blocks
per inch that it will use, and multiply that by 2. Use that as the
number of dots per inch (DPI) for your image.
Say you have a 600 DPI color printer that uses 4-pixel halftone
blocks. That is, it will use 600/4 = 150 LPI. You should then create
your images at 150*2 = 300 DPI. So, if you want an image to be 5
inches wide, then you'll have to make it 300*5 = 1500 pixels wide.
Your printing software should take all that into account to create the
proper halftoning mask. For example, when you use PostScript, you can
tell the interpreter to use a certain halftone size and it will convert
images appropriately. However, most Linux software doesn't do this yet.
If you have a need to create an image destined for print you should check
with the printer to get either the LPI or DPI and the number of pixels used
in the Halftone that will be used. You can then compute the number of
pixels you'll need in your image.
The story is very different if you do not use regular halftoning
masks. If you use a stochastic (based on randomness) dithering
technique, like Floyd-Steinberg dithering, then it may be a good idea
to design images with the same resolution as the physical (DPI)
resolution on your output device. Stochastic screening is based on
distributing the dithering error over all the image pixels, so you
(usually) get output without ugly Moire patterns and such. Then
again, using the same physical resolution as your output device can
result in really big images (in number of bytes), so you may want to
use a lower resolution. Since the dithering is more or less random,
most people won't notice the difference.
My thanks to Federico Mena Quintero for the majority of this discussion.
He summarized the discussion for the GIMP Developers Mailing List quite
some time back. Fortunately, I happened to hang onto this his posting.
How many frames makes a movie?
The following comes from Larry Gritz in response to a question I posed to
him regarding something I noticed while framing through my copy of Toy
Story one day. I thought his explanation was so good it deserved a
spot in the Muse. So here it is.
BTW: I noticed, as I framed through various scenes, that I had 4 frames of
movement and one frame of "fill" (exactly the same as the previous frame).
Standard video is 30 frames/sec and I've read that 15 or 10 animated frames
is acceptable for film but that this requires some fill frames. Lets see,
if you did 15 frames per second you could actually render 12 frames with 3
fill frames. Is this about right?
No, we render and record film at a full 24 frames a second. We
do not "render on two's", as many stop motion animators do.
When 24 fps film is converted to video, something called 3:2 pulldown
is done. Video is 30 frames, but actually 60 fields per second --
alternating even and odd scanlines. The 3:2 pulldown process records
one frame for three fields of video, then the next frame for 2 fields
of video. So you get something like this:
| video frame
| video field
| film frame
|
| 1
| 1 (even)
| 1
|
| 1
| 2 (odd)
| 1
|
| 2
| 1 (even)
| 1
|
| 2
| 2 (odd)
| 2
|
| 3
| 1 (even)
| 2
|
| 3
| 2 (odd)
| 3
|
| 4
| 1 (even)
| 3
|
| 4
| 2 (odd)
| 3
|
| 5
| 1 (even)
| 4
|
| 5
| 2 (odd)
| 4
|
So every 4 film frames get expanded into 5 video frames, and hey,
30/24 == 5/4 ! This is how all films are transferred to video
in a way that doesn't mess up the original timing.
Your video probably only shows the first field when you're paused,
which makes it look like 1 in 5 frames is doubled, but it's actually
just a bit more complicated than that.
"Linux Gazette...making Linux just a little more fun!"
Intranet Hallways Systems Based on Linux
Using Linux: An Intranet
Hallways System
Like many of you, I like to use Unix, esp.
Linux when ever and where ever it seems to be the best fit for the job.
This means I have to work fast and be creative; making opportunities when
and where ever I can't take them. I had just such an opportunity recently
when I put together a system which allows my
workplace to publish the common file sharing areas of its Microsoft
Windows NT based desktops. I thought others might be interested in this
system and created a distribution
have your own Intranet Hallways system or as the popular press would put
it an "enterprise information warehouse". Don't let on how easy it
is and you'll be able to make a bundle reselling the system. Here's
what you need to do to make it happen:
Kernel Options
Support Utilities
HTML pages and scripts
Some Configuration Changes
A Quick installation
Other things you might
do with it
Once you've retrieved the distribution,
it shouldn't take more than an hour to get things running; let me
know what you think about the system when you do.
The Opportunity
Microsoft's Windows NT suffers from a
file system inherited from its MS-DOS lineage. For those of you who haven't
had the displeasure this means file systems are cryptically named A-Z,
can't automount and the process of manually mounting them is much more
complicated and error prone than the more user friendly tools like Red
Hat's
fstool. These problems have been worked around somewhat at my agency through
a series of .bat files which mount server drives in standard places so
users can say "Just look at the T: drive" or something similar. This still
left users with problems searching tens of thousands of files spread thousands
of directories located on servers across the world. The Microsoft Windows
NT operators were trying to figure out a way to present an efficient, agency-wide
view of these servers so that users could easily find and retrieve things.
We used Linux to integrate and publish these file sharing areas on our
intranet.
Before theShow
Key to the system is the ability of the
Linux kernel (later 2.0 and 2.1 versions) to mount local
NTFS and remote SMB
volumes. There's nothing esoteric about enabling or using this option,
just check it off when
you're compiling the kernel. (Don't run away at the thought of compiling
a kernel! Most distributions
include these options in their default kernel so you probably don't have
do anything- just try it out smbmount
and see if it works). If any of your network shares are coming from Windows
95 machines, make sure to also select the patch for Windows 95 machines
and long file names. If you are just serving Microsoft Windows NT or Samba
shares, don't use the Windows 95 option as I've found it has a noticeable
impact on the speed of the SMB mount and file operations.
Once you've got an SMB capable kernel installed
you're almost ready to go. The other critical components are thesmbfs
utilities, the wu-ftpd
suite, a web server, a search engine
and a javascript - capable browser.
Your distribution has probably installed an operational FTP and HTTP server
and most people nowadays have a Netscape browser installed so all you really
need to do is compile the smbfs utilities and setup a search engine. If
most of the documents on your SMB shares are in text or HTML format, there
are a number of search engines that you can choose from- htdig and glimpse
come to mind. If you want to be able to search non-HTML documents then
you might need one of the commercial search engine. We use Netscape's catalog
server for Solaris.
The system will work without a javascript
browser; it just won't be a easy to use. Hit
the links to grab the software tools you need from the list above set it
up. If you run into problems, be sure and check out the linux HOWTOs and
mailing list documentation on the sites offering the software. If
you have RedHat's RPM or Debian's package tools somebody else has probably
already made a binary available; just check your local archive.
Set andStage
I'm assuming you've tested your kernel
to make sure you can indeed mount SMB shares and that your ftp server is
up and alive. Before we can start serving your "enterprise information
warehouse" there are a few files which need to be added to or modified
on your system in addition to the HTML
files we'll discuss later. The first addition is a new init.d file for
automatically mounting SMB shares when you boot your system. Then we'll
enable a few features of your FTP server.
First, let's contend with mounting shares
automatically. I do this with a standard run-level 3/5 initscript; here's
an excerpt with the most critical lines:
# Check that networking is up.
[ ${NETWORKING} = "no" ] exit 0
# See how we were called.
case "$1" in
start)
echo -n "Mounting SMB shares..."
echo "Mounting share1"
/usr/sbin/smbmount //hostname/share /home/ftp/mountpoint -n
-uftp -gftp -f755 -Ihostnames_IP_address
# mount your other shares
echo ""
;;
stop)
echo -n "Umounting SMB shares..."
/usr/sbin/umount /home/ftp/mountpoint
#insert other mount comments here ....
echo ""
;;
*)
echo "Usage: hallways {start|stop}"
exit 1
esac
The smbmount(8)
and umount(8) man pages have
more details on what all those flags are about. Basically, we are mounting
the shares into a directory accessible via anonymous FTP. The permissions
and groups are "fake" in the sense that they don't map to anything sensible
in the NT file system; they are only for the convenience and protection
of the Unix system. Our common shares are read/write for everyone; if your
site is more cautious you may want to review the implications of the file
permissions and ownership or perhaps impose access controls using your
file system and web server's security mechanisms.
Now, let's take a look at the scripts used
to startup your FTP server. You have to make sure you're taking advantage
of wu-ftpd's ftpaccess(5)
configuration capabilities. If you start your FTP daemon using the -a
option the /etc/ftpaccess
file will allow you to customize many aspects of the FTP server's performance
and capabilities. Normally, you enable the -a option of your FTP server
in your /etc/inetd.conf file;
some people run their FTP full time, in this case check out the startup
files in your /etc/rc.d/rc3.d
or rc5.d directory and add
the option when the daemon is started up. Among the benefits of using ftpaccess
is the ability to specify header and trailer messages in the directory
listings generated by your FTP server. These directives, message
and readme are
key to our system's capabilities.
We created an HTML
file within the directory structure accessible to the FTP daemon; in our
case it is called 'welcome.html', this file is placed in the root directory
of the FTP daemon's file area and the entry in ftpaccess looks
like:
...
message /welcome.html login
...
Now the contents of welcome.html
will be displayed at the beginning of directory listings. The contents
of welcome.html are a little
tricky if you're not familiar with javascript. They are designed to both
dynamically tailor the HTML based on the position of the page within a
browser. These dynamic web pages tailor the help message to the context
of the display.
<HTML>
<HEAD>
<SCRIPT LANGUAGE="JavaScript">
function OpenNewWindow()
{
alert("To Upload a file go to file...Upload File on the browser's
button bar")
parent.frames[2].location.protocol = "ftp:"
window.open(parent.frames[2].location.href)
}
</SCRIPT>
</HEAD
<BODY bgcolor="#FFFFFF">
<FORM>
<SCRIPT LANGUAGE="JavaScript">
if (self!=top) {
document.write('<i><B>Hi!</b></i>' + "You can preview,
download files or search for information here.<p>You can also upload
a file<br>" + '<FORM>' +
'<CENTER>' + '<INPUT TYPE="button" Value="Upload File"
onClick="OpenNewWindow()
">' + '</CENTER>' + '</FORM>');
}
else
{
document.write('<i><B>Hi!</b></i> This is a special
screen for adding information to hallways.<p> To Upload a file, go to
FILE | Upload, like <a href="http://webserver/access_directory/file_upload.gif">
this</a>
<p>');
}
</SCRIPT>
</FORM>
</BODY>
</HTML>
This interface is not the first one we
tried. I really wanted to make the system intuitive; then we'd have to
spend less time answering questions and could spend more time working on
new ideas. The tests we conducted showed most people knew how to download
files but were not aware you could upload files or view the contents of
non-HTML files. We tried HTTP uploads and downloads but settled on the
combination of FTP and HTTP generated screens. We needed a design which
allowed easy navigation around a complicated system and kept at least minimal
help hints in front of the users all the time. The final HTTP based frame
design allowed us to put together an attractive interface. Encapsulating
the FTP file display simplified uploads and downloads. Unlike a web server,
our FTP server labels all files as a single MIME type allowing us to use
a single helper application to easily display all files.; Getting this
preview function to work will require editing the association of mine types
with an application on the user's computer. We use a universal viewer,
you can use one of these if your network already has one installed or you
might investigate one of the many plug-ins which allow viewing files within
the browser itself.
The Curtain
Rises
Now the majority
of the work and trickery is done; all that remains is a frame based user
interface, a few snazzy graphics and some help files. In a nutshell,
if the FTP listing is contained within a frame then the if part of the
conditional is presented. This HTML allows the user to press an "upload"
button which will pop open another browser instance with the FTP directory
within the root window. When welcome.html
is displayed within this root window, it contains instructions on how to
upload a file using the FTP capabilities of the browser. The
best way to understand how the code works is of course to just load it
up and experiment.
This isn't a tutorial on HTML so I'll just
let you know you can download this whole package (minus a few of the graphics
we used in our user interface) from ftp://www.disa.mil/pub/linux_gazette_stuff.tgz.
We can't redistribute some of the graphics we use but you can just draw
up your own and stick them into HTML code.
During your review of the code you may
notice that our frame definition document distributes this system across
several machines; for us this is an important feature. We make use of local
proxy servers for FTP and HTTP traffic. These proxy servers keep down the
loading of our backbone. Our system is distributed such that the web server
documents and graphics will be served from a local departmental web server
while the FTP server distributes information from another, centralized
location. Since the proxy and web are local to our subnet documents stored
on the SMB hallways area are served from the proxy (cache)- speeding up
the file transfer times dramatically and reducing our wide area network
traffic. We are also using the Solaris version of the Netscape Catalog
Server to allow users to expediently find any document or content within
a wide variety of popular Unix, MacIntosh and Windows application formats.
This feature provides some much needed help to users who must retrieve
one of several hundred thousand documents stored on servers spread across
the globe; it was absolutely infeasible using the Microsoft Windows NT
file manager search feature previously recommended by the Microsoft Windows
NT operators
Applause
and Royalties
You can provide many other enhancements
such as browser access to multiple file system types (NFS, Appleshare,
SMB, AFS, etc) and internet/intranet FTP areas are easily added. We are
also working on a management add-on using PHP/FI and Postgress to present
users with a fully graphical file upload facility which will also store
meta data on documents such as the originator of the information, the originators
e-mail address, etc. In fact I think with a little more work this system
is a pretty good replacement for some the proprietary commercial document
management applications that cost tens of thousands of dollars.
I hope these ideas and this system will
help you and your workplace out. If you have other creative examples of
simple systems that help bring people working around the world together,
I'd like to here about them. Thanks
for listening...
Copyright © 1997, Justin Seiferth
Published in Issue 19 of the Linux Gazette, July 1997
"Linux Gazette...making Linux just a little more fun!"
Linux and Artificial Intelligence
Three years ago when I was starting my last year of my masters of
philosophy degree. I found myself asking that eternal question,
"Ok, now what in the hell am I going to do?" Not wanting to
continue on in philosophy, what could a philosopher (and computer
enthusiast) do that would be both fun and profitable. Artificial
Intelligence of course (but you saw that coming didn't you?)
I had fallen in love with Linux in late 1993 and after seeing all
the Suns scattered about the AI Dept, it seemed like the perfect
OS for AI research. Guess what, I was right. I have found so many
resources available for doing AI research on Linux that I had to
write them all down (warning: blatant plug follows), thus my Linux AI/Alife
mini-HOWTO came into being.
Ok, enough of this drivel, now on to the meat of the article.
Modern AI is a many faceted field of research, dealing with
everything from 'traditional' logic based systems, to
connectionism, evolutionary computing, artificial life, and
autonomous agents. With Unix being the main platform for AI, there
are many excellent resources available for Linux in each of these
areas. The rest of this article I'll give a brief description
of each of these areas along with one of the more interesting
resources available to the Linux user.
- PROGRAMMING LANGUAGES
-
I know I didn't mention this above, but there are many
programming languages that have been specifically designed
with AI applications in mind.
- DFKI OZ
Web page: www.ps.uni-sb.de/oz/
FTP site: ps-ftp.dfki.uni-sb.de/pub/oz2/
-
Oz is a high-level programming language designed for
concurrent symbolic computation. It is based on a new
computation model providing a uniform and simple foundation
for several programming paradigms, including higher-order
functional, constraint logic, and concurrent object-oriented
programming. Oz is designed as a successor to languages such
as Lisp, Prolog and Smalltalk, which fail to support
applications that require concurrency, reactivity, and
real-time control.
DFKI Oz is an interactive implementation of Oz featuring a
programming interface based on GNU Emacs, a concurrent
browser, an object-oriented interface to Tcl/Tk, powerful
interoperability features (sockets, C, C++), an incremental
compiler, a garbage collector, and support for stand-alone
applications. Performance is competitive with commercial
Prolog and Lisp systems.
- TRADITIONAL ARTIFICIAL INTELLIGENCE
-
Traditional AI is based around the ideas of logic, rule
systems, linguistics, and the concept of rationality. At its
roots are programming languages such as Lisp and Prolog.
Expert systems are the largest successful example of this
paradigm. An expert system consists of a detailed knowledge
base and a complex rule system to utilize it. Such systems
have been used for such things as medical diagnosis support
and credit checking systems.
- SNePS
Web site: www.cs.buffalo.edu/pub/sneps/WWW/
FTP site: ftp.cs.buffalo.edu/pub/sneps/
-
The long-term goal of The SNePS Research Group is the design
and construction of a natural-language-using computerized
cognitive agent, and carrying out the research in artificial
intelligence, computational linguistics, and cognitive science
necessary for that endeavor. The three-part focus of the group
is on knowledge representation, reasoning, and natural-language
understanding and generation. The group is widely known for its
development of the SNePS knowledge representation/reasoning
system, and Cassie, its computerized cognitive agent.
- CONNECTIONISM
-
Connectionism is a technical term for a group of related
techniques. These techniques include areas such as Artificial
Neural Networks, Semantic Networks and a few other similar
ideas. My present focus is on neural networks (though I am
looking for resources on the other techniques). Neural
networks are programs designed to simulate the workings of the
brain. They consist of a network of small mathematical-based
nodes, which work together to form patterns of information.
They have tremendous potential and currently seem to be having
a great deal of success with image processing and robot
control.
- PDP++
Web site: www.cnbc.cmu.edu/PDP++/
FTP site (US): cnbc.cmu.edu/pub/pdp++/
FTP site (Europe):
unix.hensa.ac.uk/mirrors/pdp++/
-
As the field of connectionist modeling has grown, so has the
need for a comprehensive simulation environment for the
development and testing of connectionist models. Our goal in
developing PDP++ has been to integrate several powerful
software development and user interface tools into a general
purpose simulation environment that is both user friendly and
user extensible. The simulator is built in the C++ programming
language, and incorporates a state of the art script
interpreter with the full expressive power of C++. The
graphical user interface is built with the Interviews toolkit,
and allows full access to the data structures and processing
modules out of which the simulator is built. We have
constructed several useful graphical modules for easy
interaction with the structure and the contents of neural
networks, and we've made it possible to change and adapt many
things. At the programming level, we have set things up in
such a way as to make user extensions as painless as
possible. The programmer creates new C++ objects, which might
be new kinds of units or new kinds of processes; once compiled
and linked into the simulator, these new objects can then be
accessed and used like any other.
- EVOLUTIONARY COMPUTING [EC]
-
Evolutionary computing is actually a broad term for a vast
array of programming techniques, including genetic algorithms,
complex adaptive systems, evolutionary programming, etc.
The main thrust of all these techniques is the idea of
evolution. The idea that a program can be written that will
evolve toward a certain goal. This goal can be
anything from solving some engineering problem to winning a
game.
- GAGS
Web site: kal-el.ugr.es/gags.html
FTP site: kal-el.ugr.es/GAGS/
-
Genetic Algorithm application generator and class library
written mainly in C++.
As a class library, and among other thing, GAGS includes:
- A chromosome hierarchy with variable length
chromosomes. Genetic operators: 2-point crossover,
uniform crossover, bit-flip mutation, transposition (gene
interchange between 2 parts of the chromosome), and
variable-length operators: duplication, elimination, and
random addition.
- Population level operators include steady
state, roulette wheel and tournament selection.
- Gnuplot wrapper: turns gnuplot into a
iostreams-like class.
- Easy sample file loading and configuration file parsing.
As an application generator (written in PERL),
you only need to supply it with an ANSI-C or C++ fitness
function, and it creates a C++ program that uses the above
library to 90% capacity, compiles it, and runs it, saving
results and presenting fitness thru gnuplot.
- ALIFE
-
Alife takes yet another approach to exploring the mysteries of
intelligence. It has many aspects similar to EC and
connectionism, but takes these ideas and gives them a
meta-level twist. Alife emphasizes the development of
intelligence through emergent behavior of complex
adaptive systems. Alife stresses the social or group
based aspects of intelligence. It seeks to understand life and
survival. By studying the behaviors of groups of 'beings' Alife
seeks to discover the way intelligence or higher order
activity emerges from seemingly simple individuals. Cellular
Automata and Conway's Game of Life are probably the most
commonly known applications of this field.
- Tierra
Web site: www.hip.atr.co.jp/~ray/tierra/tierra.html
FTP site: alife.santafe.edu/pub/SOFTWARE/Tierra/
Alternate FTP site: ftp.cc.gatech.edu/ac121/linux/science/biology/
-
Tierra's written in the C programming language. This source
code creates a virtual computer and its operating system,
whose architecture has been designed in such a way that the
executable machine codes are evolvable. This means that the
machine code can be mutated (by flipping bits at random) or
recombined (by swapping segments of code between algorithms),
and the resulting code remains functional enough of the time
for natural (or presumably artificial) selection to be able to
improve the code over time.
- AUTONOMOUS AGENTS
-
Also known as intelligent software agents or just agents, this
area of AI research deals with simple applications of small
programs that aid the user in his/her work. They can be mobile
(able to stop their execution on one machine and resume it on
another) or static (live in one machine). They are usually
specific to the task (and therefore fairly simple) and meant
to help the user much as an assistant would. The most popular
(ie. widely known) use of this type of application to date are
the web robots that many of the indexing engines
(eg. webcrawler) use.
- Ara
Web site: www.uni-kl.de/AG-Nehmer/Ara/
-
Ara is a platform for the portable and secure execution of
mobile agents in heterogeneous networks. Mobile agents in this
sense are programs with the ability to change their host
machine during execution while preserving their internal
state. This enables them to handle interactions locally which
otherwise had to be performed remotely. Ara's specific aim in
comparison to similar platforms is to provide full mobile
agent functionality while retaining as much as possible of
established programming models and languages.
Copyright © 1997, John Eikenberry
Published in Issue 19 of the Linux Gazette, July 1997
"Linux Gazette...making Linux just a little more fun!"
Linux: For Programmer Only--NOT!
A couple of weeks ago, I was in a computer repair shop, trying to get a
deal on some hardware. The owner was trying to sell me on how cool Win95 is. I told
him I run Linux, then gave him the same hard/soft sell I give to every
one that I think might have use for Linux. I'm just a glutton for
punishment that way. He looked at me blankly, and said Unix is a
programmer's OS and it's not good for the average user. My turn to look
blankly, "Apparently that means that MS is an illiterate's OS, and not
good for the educated user". I didn't say that but I thought it
very loudly, and the conversation was over....
I should have been more understanding of his attitude. Part of the reason
that Linux hasn't become more mainstream is the belief that you must be a
highly trained programmer to make it run. That simply isn't the case.
I hope to dispel some of this notion by pointing out my personal
experience with Linux. I am not a programmer, I can barely write a good
shell script, but I am happy as a clam with my Slackware 3.2 beta
installation and only very infrequently boot to the DOS/WFWG 3.11
partition.
Programming consists of writing code and compiling it, and
very little of this is required to effectively use Linux. Although many
applications are distributed as source code, the source code in most cases
require very little modification. Compiling source code, moreover is not
as complicated as it might seem. One command, "make" can usually
accomplish this compilation and the advice to inspect MakeFiles can
largely be ignored(I probably should be horsewhipped for the previous
statement, but in my experience it's nonetheless true.).
There is no doubt that the Linux experience is enhanced by programming
ability. Linux does lend itself to source code modification, which is part
of the reason that its development and bug fixes have been so rapid, and
continuous improvement has been the hallmark of Linux, as well as the
whole of the GNU organization.
It might be closer to the truth to consider Linux a hacker's medium,
simply because "hacker" means different things to different people.I do
not consider myself a hacker, although several MS Windows users have
described me that way. "Hacker", "cracker" and "programmer" are, in my
opinion often erroneously used as synonyms, by people who haven't acquired
computer skills beyond user level.
This myth is probably furthered by manufacturers of the more well known
OS, although not necessarily deliberately. Salesmanship requires
manipulation of certain facts, and in the case of OS software, this is
even more likely to be the case. FACT: There is no perfect OS. FACT:
Proponents of any OS tend to misplace that fact, even Linux advocates.
In my own family there exists a conflict of opinion regarding WFWG 3.11
vs. Linux, which in time is growing weaker, with Linux becoming more
acceptable to my wife and kids(I have admittedly used subversive
techniques to accomplish this goal, such as leaving the computer on all
the time, in X). In addition, I made sure to download programs that were
similar to ones used by my kids in WFWG, such as xpaint, and Netscape, as
well as several games, both SVGALIB, and X. Koules is a big favorite, as
is SASTEROIDS, and some while ago I had a flight sim, FLY8111, that was a
litle too challenging so it quietly disappeared. I have put the BSD text
based games on as an inducement to get my 15 year old foster son to read
with some enthusiasm, with moderate success. All I have to do now is find
a word processing application that my wife will accept readily, and I'll
experience little resistance, hopefully to commandeering the drive that's
currently loaded with DOS and WFWG.When I recompiled the kernel, I added
sound support, and even though I've had a little trouble installing a
sound playing program, the kids and I still make use of a pair of
extremely basic scripts based on the drivers README that allow us to
record and playback music. My sound card is an old eight bit SoundBlaster
so the sound quality isn't great, but I used it to rehearse the song I
sang at my oldest daughter's wedding, to good effect.
Earlier, I stated that I'm not really capable of writing a decent shell
script, but very simple scripts similar to DOS batch files can be written
by nearly anyone, and examples of scripts abound on many sites, so
keystroke saving measures are available to any one who cares to try their
hand at it. The Linux Gazette, in particular has provided me with plenty
of template like scripts from which I have learned what little I know
about more advanced scripting.
Linux advocates need, in my opinion to show patience with new users to a
greater degree than is currently the fashion. Banter among the initiated
has camaraderie value, but often puts off the prospective Linux convert.
When I was investigating Linux, I was told by one respondent to my usenet
posting "Do not meddle in the ways of wizards for their ways are subtle
and quick to anger." Hardly an encouraging statement, but with my
temperament it served to strengthen my resolve to show the SOB. I daresay
most casual computer users would not respond as I did, however.
For the advancement of Linux I would recommend that you (Linux gurus)
choke on RTFM, unless you're sure that the person you are talking to has
acquired the skills needed to effectively read those FMs. My experience
has shown me that Linux distributions are almost as plug and play as
anything MS, IBM, Apple or anyone else has to offer. This provides a
jumping off point that will motivate users to learn skills that they
previously thought to be beyond them. By drawing them into Linux operation
slowly, they may become capable programmers, at which point they will have
made it their OS. A programmer's OS.
Copyright © 1997, Mike List
Published in Issue 19 of the Linux Gazette, July 1997
"Linux Gazette...making Linux just a little more fun!"
QPS, A New Qt-Based Monitor
Introduction
The Qt C++ software development toolkit, by Norway's Troll Tech, has been
available long enough now that applications are beginning to appear which use
Qt rather than Motif, Xlib or Tcl/TK. Programs developed with Qt have an
identifiable and distinctive appearance, with some resemblance to both Windows
and Motif. There has been some resistance in the Linux community to
widespread adoption of the toolkit due to its hybrid licensing arrangement.
The toolkit is freely available in the Linux version, and its use in the
development of free, GNU-ish software is free and unrestricted, but for other
platforms and for commercial Linux software Qt is a commercial product.
Remember when Tcl/Tk began to become widely used a couple of years ago?
Applications and utilities written with the toolkit began to proliferate, one
reason being that the learning curve is relatively gentle and a quick X
interface to a command-line utility could be contrived in a short time. C
programmers found that the guts of a program could be written in C, while the
tricky X-windows interface could be quickly put together with Tcl/Tk. This
benefited the Linux community as a whole, making it easier for new users and
developers to gain a foothold on the sometimes forbiddingly steep unix
terrain.
Qt is an entirely different sort of toolkit than Tk, since it is based on
C++ and doesn't have the interpreted script layer of Tk. (It more closely
resembles Bruce Wampler's V
package, described in the Dec. 1996 issue of Linux Journal.) In order to run QT
applications the libqt shared lib must be available as well as a
small executable, moc. The Qt header (include) files are needed as
well to compile these applications from scratch. The Qt source package is
available from the Troll Tech FTP site.
Many small sample applications and demos, as well tutorials and ample
documentation, are included in the package.
QPS
Mattias Engdegård has recently
written and released a process monitor similar to top, the classic
interface to ps. Top, though a character-mode application,
is commonly run in an xterm or rxvt window in an X session. There is one
problem with top in a window; scrolling down to the bottom of the
process list doesn't work, so the entries at the bottom are inaccessible
without resizing the window. There may be a way to do this, but I haven't
been able to find one. A minor issue, I suppose, since the
ordering of the entries can be easily toggled so that either the most
memory-intensive or the most CPU-intensive processes appear at the top.
Qps is a more X-friendly application than top, with scrollbars and
a mouse-oriented interface. Clicking on any of the header categories, such as
%CPU, SIZE, or %MEM, will sort the processes in descending order.
Alt-k will kill a highlighted process. A series of bar-graphs
along with an xload-like meter form a status bar at the top of the window.
This can be toggled on and off from the menu-bar. When Qps is iconified the
icon is the small xload-like pane from the status-bar, which is a nice touch.
Here's a screenshot:
Qt applications don't use the X resources typical of most X programs; one
result of this is that Qps seems to be confined to the default white, gray,
and black color scheme. It can generate a resource file in your home
directory which specifies which fields you'd like to see and whether the
status-bar should be visible or not.
Qps could be thought of as a sort of second-generation Linux utility,
written for users who rarely work from the console and boot directly into an X
session. It should fit in well with the KDE
suite of applications, which are also being developed with Qt. Though it uses
more memory than top in an rxvt window, I find myself using it often
while running X. I think this is a solid, dependable application and deserves
attention from the Linux community.
Availability
Currently the Qps-1.1 source is in the Sunsite
Incoming directory, but
will most likely end up in the
status directory.
An alternate Swedish site is
here.
Copyright © 1997, Larry Ayers
Published in Issue 19 of the Linux Gazette, July 1997
"Linux Gazette...making Linux just a little more fun!"
The UnRpm-Install Package
Introduction
No matter what distribution of Linux you have installed, there will come a
time when you would like to install a package in one of the other
distribution's formats. No one distribution has available every possible
package, and the updates to packages often depend on a volunteer's inclination
and time constraints.
On a reasonably current and well-maintained Linux system, most of the
quality source-code packages will compile without much effort beyond perusal
of the README and INSTALL files. In other words, *.rpm and
*.deb packages aren't vitally necessary, though the ease of upgrading
or removal possible with these packages makes them a time-saving convenience.
But few people have both the time and/or inclination to compile every new
program from source. It does take more time than using a precompiled
package, and often a package maintainer will have access to patches which
haven't yet been incorporated into an official release. One of these patches
might be just what it takes to insure a successful installation on your
system! Therefore it stands to reason that the more different genera of
precompiled packages you have available, the wider the pool of available
software.
A year and a half ago I was running a Slackware 3.0 system, but had used
Redhat just long enough to appreciate the value of an rpm package. As I
remember, there were a few pieces of software which I was unable, no matter
what tweaking I did, to successfully compile. The rpm's available for those
packages were tempting, but I didn't want to start from scratch and reinstall
the Redhat Linux distribution just for a few packages. Poking around the
Redhat FTP site, I saw that the source for the then-current version of rpm
was available, and after various trials and tribulations I managed to
successfully compile and install it. The crucial factor which made it all
work was downloading and installing a newer version of cpio, which was
right there in the Redhat rpm directory. It wasn't the easiest installation
I've ever done, but I don't blame the folks at Redhat for not making it a
no-brainer. After all, they evidently worked long and hard developing the rpm
package system and they surely wanted to leverage its value in influencing
users to buy their distribution. Redhat is to be commended for resisting
purely commercial urges and making rpm freely available.
Two distributions later, I never have gotten around to reinstalling rpm,
partly because the Debian distribution has a utility called alien,
which will convert an *.rpm file into a *.deb file. This is
a nice utility, but sometimes I'd just like to poke around inside a package
and see what's there without actually installing it. Both rpm and Debian's
dpkg utility have command-line switches for just listing the
contents, or extracting individual files from a package. These aren't the
sort of switches I would use often enough to memorize, and it's a pain to read
the man page each time. So I gradually meander my way to the point of this
article...
UnRpm-Install
Recently, in nearly daily updates,
Kent Robotti has been releasing to the Sunsite archive site a
package of programs and scripts which simplify working with these various
package formats. UnRpm is most useful when used in conjunction with the
Midnight Commander file manager, as one component of the package is a
set of entries meant to be appended to the mc user menu.
This is what the package includes:
- the version of cpio which works well with rpm
- two shell scripts from the Slackware distribution, installpkg
and removepkg
- rpm2cpio, a program from Redhat which converts an rpm
archive to a cpio archive
- dpkgdeb, a program from the Debian distribution which unpacks,
packs, or provides information about a Debian archive file
- unrpm and undeb, two shell scripts which can either be
used as is or be called by the Midnight Commander.
- Update.mc, a shell script which will append entries for the above
scripts and programs to the /usr/lib/mc/mc.menu file
- Install, a shell script which installs the above binaries and
shell scripts, and also thoughtfully renames any pre-existing
equivalents in case you may want to back out any of the installed files
The earlier versions of UnRpm-Install included statically-linked binaries, no
doubt to make them usable by a wider variety of users, but with the
disadvantage of large binaries. Since most systems have compatible
libc versions installed, which is the only library linked with the
binaries, recent versions have included the smaller dynamically-linked
versions.
The Midnight Commander in its recent incarnations has excellent
support built-in for treating these various archive formats as virtual
file-systems, allowing the user to browse through their contents without
actually expanding them. The menu entries provided by UnRpm expand upon these
capabilities, making it easier than ever to convert one format to another and
to see just what an archive will install on your system.
There's nothing in UnRpm-Install which you couldn't gather up yourself, from
various FTP sites or distribution cd's. What makes the package valuable is
that Kent Robotti has done this for you, and presented these disparate
binaries and scripts as a coherent whole, bound together by the Midnight
Commander used as archive manager.
Availability
Various versions of UnRpm-Install are still in the /pub/Linux/Incoming directory of
the Sunsite FTP
archive, but the most recent version will eventually make its way into
the archive
utility directory.
Copyright © 1997, Larry Ayers
Published in Issue 19 of the Linux Gazette, July 1997
"Linux Gazette...making Linux just a little more fun!"
Single-User Booting Under Linux
I was trained as a system administrator on HP, IBM, and Sun workstations
while working as a DRT consultant assigned to Informix as an alpha-tester.
There I learned the need for a true single-user operating mode in Unix.
When I tried to use the single user mode with Linux, it did not work in the
way that I expected. After many, many reboots I worked out the right
configuration to support a true single-user mode on the distribution I was
using, Slackware 3.2, by modifying the boot process.
This article will now explain how to setup the bootup process for Linux so
that single-user mode really works if you are using the Slackware 3.2
distribution (or a derivative). I will begin by assuming that your kernel
is correctly configured and that the init program starts successfully.
See the Installation-HOWTO at
ftp://sunsite.unc.edu/pub/Linux/docs/HOWTO/Installation-HOWTO
for help to get this far. Once you have a system that boots, however, you
have only begun. Why? Most distributions will give you a generic set of
initialization scripts that are designed to work for an average installation.
You will want to customize this in order to run extra things you want and/or
to prevent running things you do not want. With the dozen or so standard
startup scripts things can seem confusing, but after you read this article
you should be able to understand enough to create a custom environment
when you boot that exactly suits you.
As I stated earlier, I will begin by assuming that init has started
successfully. It will examine the file /etc/inittab to determine
what to do. In that file are located the lines to activate your login
devices such as terminals, modems, and your virtual consoles. Leave that
stuff alone. What we are interested in are the lines which call the
startup/shutdown scripts. These lines will look something like this:
# Default runlevel.
id:3:initdefault:
# System initialization (runs when system boots).
si::sysinit:/etc/rc.d/rc.S
# Script to run when going single user (runlevel 1).
l1:1:wait:/etc/rc.d/rc.K
# Script to run when going single user (runlevel S or s)
mm:S:wait:/etc/rc.d/rc.K2
# Script to run when going multi user.
rc:23456:wait:/etc/rc.d/rc.M
# Runlevel 0 halts the system.
l0:0:wait:/etc/rc.d/rc.0
# Runlevel 6 reboots the system.
l6:6:wait:/etc/rc.d/rc.6
The comments are present and are very helpful. First you need to determine
your default runlevel. In this case it is 3. The format of the /etc/inittab
file section we are looking at is simple. Blank lines are ignored. Lines
with '#' as the first character are comments and are ignored. Other lines
have 4 parts separated by the colon character. These parts are 1. symbolic
label, 2. runlevel, 3. action and 4.command to run. These are documented in
the section 5 manual page for /etc/inittab (man 5 inittab). First
we must find a line with an action of initdefault, and then see what runlevel
it has. That will be the default runlevel. Obviously you should not have 2
lines that have initdefault as the action in an /etc/inittab file. Once you know
the default runlevel, you will be able to know what /etc/inittab entries
will be processed by init. The 1 runlevel is considered single-user
maintenance mode, but it supported multiple simultaneous logins in virtual
terminals with the default /etc/inittab on my systems. You can prevent this by
removing the 1 from the getty lines of the tty2, tty3, tty4, etc. The 3
runlevel is considered the normal multi-user mode with full networking
support. The S runlevel is supposed to be true single-user, and you can
theoretically enter that runlevel using the lilo parameter
single. However, for the Slackware 3.2 distribution, that does
not put you in a single-user mode as you would expect, but instead you wind
up in runlevel 3. The /etc/inittab file I show here does not have that problem
however. Once you have read this article you can change the system to
behave in the expected manner. So we know we will go to runlevel 3. That
means init will perform every command in the /etc/inittab file that has a sysinit,
then boot, or bootwait, and finally any entries for our runlevel 3. When you
want to run a script when entering a runlevel, it doesn't make sense to have
more than one script line in the /etc/inittab file for that level. Instead, you
should put everything in 1 script, or call scripts from within the script
mentioned in the /etc/inittab file using the dot method. Once thing to note is
that field 2, the runlevel field, can have more than 1 runlevel specified.
The init program will first run the si entry
(and we will wait for it to finish running /etc/rc.d/rc.S) since it has
sysinit (which implies wait) in the third field. Then it will run everything
with 3 specified. So in our example file we will run the si target, then
the rc target (and we will wait for it to finish running the
/etc/rc.d/rc.M script since the third field is wait), and finally
we it will do the c1 through c6 targets which set up the virtual ttys during
a normal boot.
If we boot (via lilo) and add the single
parameter, we will still run the si target (/etc/rc.d/rc.S) and wait for it to
complete, but then we will run the mm target (/etc/rc.d/rc.K2). Keep in mind
that runlevel 1 and runlevel S are essentially the same when you enter them,
but how you get there is very different. Runlevel 1 can be entered by using
the command /sbin/telinit 1, but /sbin/telinit s will send you to runlevel 5
often for some reason (some kind of bug). Runlevel 1 will give you a normal
log in, and allows 1 user (any 1 user) to log in at the console.
With this setup, runlevel S will give you a special root-only login that
allows only root to use the console. Since only root can log in, only a
special password prompt is displayed. If you press enter or ctl-D, the system
will return to runlevel 3. This root-only login is accomplished by using
the /bin/sulogin program. Runlevel S is probably what you want when you think
single-user, but you have to reboot the machine and use lilo and have the
single parameter to make it work. You can use runlevel 1 to accomplish the
same things, but remember you will have to manually return to runlevel 3
when you are done with another call to /sbin/telinit 3 or a reboot, and you
must insure that nobody else can get to the console but the root user.
WARNING: The true single-user mode entered with the single parameter to
lilo with my /etc/inittab and /etc/rc.d/rc.K2 will support only 1 console and no other
virtual terminals. Do not run anything that locks up the terminal!
Ok, so what do we know now? We know what scripts init will call and when they
will be called. But what can be in those scripts? The scripts should be
written for bash unless you are a real guru and KNOW the other shell you
wrote scripts for will be available during boot. There is nothing preventing
you from using perl or tcsh or whatever, but traditionally most everyone uses
bash scripts (ok, ok, Bourne shell scripts) for unix boot scripts. The /etc/rc.d/rc.S
script which is called at system boot time should take care of things like
fsck'ing your file systems, mounting them, and starting up swapping and other
essential daemons. These are things that you need independent of runlevel.
The /etc/rc.d/rc.M script which is called when you enter runlevel 3 should start all
the processes that remain that you usually need during normal system
operation EXCEPT things like getty. Processes that must be restarted whenever
they stop running like getty should be placed in the /etc/inittab file instead of
being started by a boot script. So what is in a typical /etc/rc.d/rc.M script?
Usually configuring the network , starting web servers, sendmail, and
anything else you want to always run like database servers, quota
programs, etc.
The only startup script I mention in my /etc/inittab that is not included in the
Slackware 3.2 distribution is /etc/rc.d/rc.K2, and it is merely a modified version
of /etc/rc.d/rc.K set up for single user mode. Remember this is the startup script
that will be used if you choose to enter the single parameter to lilo. At
the end of this file you will see a line:
exec /bin/sulogin /dev/console
This will replace the current process which is running the script with the
/bin/sulogin program. This means, of course, that this has to be the last
line in your script, since nothing after this line will be processed by bash.
After that program starts, it displays a message to either enter the root
password or press ctl-D. If you enter the correct root password, you will
be logged in as root in a true single-user mode. Be careful, though,
because when you exit that shell the machine will go into runlevel 3.
If you want to reboot before entering runlevel 3 you must remember to do
it (via shutdown) instead of just exiting the shell. If you press ctl-D
instead of the root password, the system will enter runlevel 3. I have
changed the incorrect calls to kill to use the killall5 program, since
the lines with kill caused init to be killed and a runlevel change was
happening incorrectly.
Well, I hope that this description of how I enabled my Linux machine to
have a single-user mode similar to that of the big-name workstations
proves helpful to you. Customizing your boot process is not too hard,
once you understand something about how the /etc/inittab
and /etc/rc.d/*
scripts work. Be sure you 1. backup your entire system, 2. have a boot
floppy, and 3. a rescue floppy that can restore the backup (or any
individual files) you made in step 1 using the boot floppy from step 2 to
boot the machine. If you make a 1 character typo you can prevent the
machine from booting, so the backup steps, while tedious, are really
necessary to protect yourself before you experiment.
The Files
Here are the files I used. Use at your own risk. They work for me, but
may need to be modified to work for you.
/etc/inittab
#
# inittab This file describes how the INIT process should set up
# the system in a certain run-level.
#
# Version: @(#)inittab 2.04 17/05/93 MvS
# 2.10 02/10/95 PV
#
# Author: Miquel van Smoorenburg, miquel@drinkel.nl.jugnet.org
# Modified by: Patrick J. Volkerding, volkerdi@ftp.cdrom.com
# Modified by: John Gatewood Ham, zappaman@alphabox.compsci.buu.ac.th
#
# Default runlevel.
id:3:initdefault:
# System initialization (runs when system boots).
si::sysinit:/etc/rc.d/rc.S
# Script to run when going maintenance mode (runlevel 1).
l1:1:wait:/etc/rc.d/rc.K
# Script to run when going single user (runlevel s)
mm:S:wait:/etc/rc.d/rc.K2
# Script to run when going multi user.
rc:23456:wait:/etc/rc.d/rc.M
# What to do at the "Three Finger Salute".
# make the machine halt on ctl-alt-del
ca::ctrlaltdel:/sbin/shutdown -h now "going down on ctl-alt-del"
# Runlevel 0 halts the system.
l0:0:wait:/etc/rc.d/rc.0
# Runlevel 6 reboots the system.
l6:6:wait:/etc/rc.d/rc.6
# What to do when power fails (shutdown to single user).
pf::powerfail:/sbin/shutdown -f +5 "THE POWER IS FAILING"
# If power is back before shutdown, cancel the running shutdown.
pg:0123456:powerokwait:/sbin/shutdown -c "THE POWER IS BACK"
# If power comes back in single user mode, return to multi user mode.
ps:S:powerokwait:/sbin/init 5
# The getties in multi user mode on consoles an serial lines.
#
# NOTE NOTE NOTE adjust this to your getty or you will not be
# able to login !!
#
# Note: for 'agetty' you use linespeed, line.
# for 'getty_ps' you use line, linespeed and also use 'gettydefs'
# we really don't want multiple logins in single user mode...
c1:12345:respawn:/sbin/agetty 38400 tty1 linux
c2:235:respawn:/sbin/agetty 38400 tty2 linux
c3:235:respawn:/sbin/agetty 38400 tty3 linux
c4:235:respawn:/sbin/agetty 38400 tty4 linux
c5:235:respawn:/sbin/agetty 38400 tty5 linux
c6:235:respawn:/sbin/agetty 38400 tty6 linux
# Serial lines
#s1:12345:respawn:/sbin/agetty 19200 ttyS0 vt100
#s2:12345:respawn:/sbin/agetty 19200 ttyS1 vt100
# Dialup lines
#d1:12345:respawn:/sbin/agetty -mt60 38400,19200,9600,2400,1200 ttyS0 vt100
#d2:12345:respawn:/sbin/agetty -mt60 38400,19200,9600,2400,1200 ttyS1 vt100
# Runlevel 4 used to be for an X-window only system, until we discovered
# that it throws init into a loop that keeps your load avg at least 1 all
# the time. Thus, there is now one getty opened on tty1. Hopefully no one
# will notice. ;^)
# It might not be bad to have one text console anyway, in case something
# happens to X.
x1:4:wait:/etc/rc.d/rc.4
# End of /etc/inittab
/etc/rc.d/rc.K
# /bin/sh
#
# rc.K This file is executed by init when it goes into runlevel
# 1, which is the administrative state. It kills all
# deamons and then puts the system into single user mode.
# Note that the file systems are kept mounted.
#
# Version: @(#)/etc/rc.d/rc.K 1.50 1994-01-18
# Version: @(#)/etc/rc.d/rc.K 1.60 1995-10-02 (PV)
#
# Author: Miquel van Smoorenburg miquels@drinkel.nl.mugnet.org
# Modified by: Patrick J. Volkerding volkerdi@ftp.cdrom.com
# Modified by: John Gatewood Ham zappaman@alphabox.compsci.buu.ac.th
#
# Set the path.
PATH=/sbin:/etc:/bin:/usr/bin
# Kill all processes.
echo
echo "Sending all processes the TERM signal."
killall5 -15
echo -n "Waiting for processes to terminate"
for loop in 0 1 2 3 4 5 6 7 ; do
sleep 1
echo -n "."
done
echo
echo "Sending all processes the KILL signal."
killall5 -9
# Try to turn off quota and accounting.
if [ -x /usr/sbin/quotaoff ]
then
echo "Turning off quota.."
/usr/sbin/quotaoff -a
fi
if [ -x /sbin/accton ]
then
echo "Turning off accounting.."
/sbin/accton
fi
/etc/rc.d/rc.K2
# /bin/sh
#
# rc.K This file is executed by init when it goes into runlevel
# 1, which is the administrative state. It kills all
# deamons and then puts the system into single user mode.
# Note that the file systems are kept mounted.
#
# Version: @(#)/etc/rc.d/rc.K 1.50 1994-01-18
# Version: @(#)/etc/rc.d/rc.K 1.60 1995-10-02 (PV)
#
# Author: Miquel van Smoorenburg miquels@drinkel.nl.mugnet.org
# Modified by: Patrick J. Volkerding volkerdi@ftp.cdrom.com
# Modified by: John Gatewood Ham zappaman@alphabox.compsci.buu.ac.th
#
# Set the path.
PATH=/sbin:/etc:/bin:/usr/bin
# Kill all processes.
echo
echo "Sending all processes the TERM signal."
killall5 -15
echo -n "Waiting for processes to terminate"
for loop in 0 1 2 3 4 5 6 7 ; do
sleep 1
echo -n "."
done
echo
echo "Sending all processes the KILL signal."
killall5 -9
# Try to turn off quota and accounting.
if [ -x /usr/sbin/quotaoff ]
then
echo "Turning off quota.."
/usr/sbin/quotaoff -a
fi
if [ -x /sbin/accton ]
then
echo "Turning off accounting.."
/sbin/accton
fi
# Now go to the single user level
exec /bin/sulogin /dev/console
zappaman@alphabox.compsci.buu.ac.th
Information about me.
Copyright © 1997, John Gatewood Ham
Published in Issue 19 of the Linux Gazette, July 1997
"Linux Gazette...making Linux just a little more fun!"
User Groups and Trade Shows: Lessons from the Atlanta Linux Showcase
User Groups and Trade Shows
Lessons from the Atlanta Linux Showcase
by Andrew Newton
Trade shows and expos are not at all uncommon in the computer industry. But not since the early
days of microcomputers, when CP/M was King and toggle switches were the user interface, have
user groups been heavily involved. So in the era of powerful non-commercial software, couldn't
the trade shows also be non-commercial?
We, the members of the Atlanta Linux Enthusiasts (ALE), found out the answer is yes.
Originating from correspondence with Linux International for some local help for Linux vendors
at COMDEX and our own Linux demo fest (called the "Geek-Off") a year earlier, we put
together a non-commercial, user group organized trade show. On June 7, 1997, we put on the
largest Linux vendor showcase to date.
Get Started With The Essentials
So let's say you, being the Linux activist of your community, want to do your bit to spread the
word. Where would you start?
Although we didn't necessarily do this, we learned there are two essential things to get a Linux
trade show off the ground: 1) a time and place, and 2) a checking account. And in the words of
our own Marc Torres, once you have those two items, "the rest grows from there."
It was a given that we would hold the Atlanta Linux Showcase as close to COMDEX as possible.
After all, this whole idea came from helping out the Linux vendors at COMDEX. Plus the idea
of getting the COMDEX crowd was good. We theorized that many people flying in for
COMDEX would stay over the following weekend to save on air fare. And they could easily
justify it if they were attending another computer show.
Picking the place was a little more troublesome, but not impossible. We finally decided on The
Inforum because it was located only blocks away from the venue for COMDEX, was in
downtown Atlanta, and well known to many.
Finally, the checking account is very important. As it turns out we didn't do this immediately
and paid the price in countless hours of meetings discussing logistics. A checking account is
important because it gives you a place from which to send money and, more importantly, a place
to receive money. People like it better when they can write checks to "Big Time Linux Event"
instead of "Bob Smurd."
One of the major inhibitors behind our acquisition of a checking account was our incredible lack
of knowledge when it comes to the law. After all, we are a bunch of computer jocks, not
attorneys. We had many seemingly endless discussions on issues such as incorporation,
non-profit status, tax codes, the right to bear arms, etc. In the end, David Hamm, one of our most
active members, just ended up going to a bank and getting a new checking account under his
control. Incidentally, David became the treasurer.
David Miller eyes a bottle of ALS Ale. - Photo by Amy Ayers
Put Time On Your Side
Unfortunately, we didn't. Of course, we had the COMDEX target date to shoot for giving us
little time between our mobilization and the event. If you can pick a date over six months out, do
so. There are multiple reasons for this, most of which have to do with reserving space.
First, you must reserve space somewhere to hold your event. We lucked out in our case, but
many venues will require booking many months ahead of time, especially the ones that don't
often cost so much money such as college campuses and state buildings.
Second, you must reserve space in print media for advertising and publicity. While we were able
to get ads in our local computer magazines and the event listed in some calendars, we did miss
deadlines elsewhere. You may have noticed there were no advertisements for the Atlanta Linux
Showcase in Linux Journal. We missed the deadline. In addition, it takes time to grease the
wheels for free publicity.
A brief word about FREE PUBLICITY - There is no such thing; you'll work for every last bit of
it. Free publicity means getting listed in upcoming events calendars and maybe an article or two
about Linux in the local paper with a small plug at the end for the event. If you do take the time
to pay for advertising, use the advertising representative as a way of getting your event some
extra publicity in that publication. Many publications put on the appearance that their articles are
completely disjoint from their advertising on the basis of journalistic ethics, but with the
exception of SSC that isn't true.
A brief word about paid advertising - It is like buying a used car. What an ad rep puts on a rate
card isn't necessarily the price you have to pay. Try talking them down. Again, this doesn't apply
to SSC.
Organize Your Volunteers
We divided our group into two major camps, organizers and volunteers. The first were the
people that planned the event out for months and did a lot of the leg work. The second were the
people that showed up the day of the show and manned the registration desk, checked badges,
etc.
You don't want to have too many organizers as it becomes difficult to manage a large group of
people over a large span of time. We divided up our group into teams of 3 or 4, with many
people being on 2 or more teams. This gave us what philosophical management types like to call
cross-functional teams. By having more than one person on a team, it helped insure no one
person was the only source of information or action.
We had the following teams:
- Vendor - contacted vendors
- Talks - organized the speakers and presenters
- Publicity - handled advertising and publicity
- Finance - dealt with our mounds of gold
- Logistics - managed booth layouts and site coordination
In hind sight, we should have also created a "Registration" team to handle all the registrations for
both walk-in and pre-paid registrations. Our answer to this was to make the Talks team and the
Logistics team work together, which worked but not as smoothly as we would have liked. It is
better to have a group of people who are solely in charge of registration and aren't distracted with
other problems.
We didn't solicit for volunteers until a month before our show. In retrospect, it probably should
have been two months. We gave our volunteers a briefing the day before the Showcase and had a
work schedule already printed when they arrived. We also required them to work 2 three-hour
shifts for manageability purposes and to keep the number of volunteers to a minimum but in the
end solicited for some more at the last minute (thanks Ben and Vicki).
A brief note about Volunteers - Treat them well, because they are working for free. And if you
do that, most will go the extra mile treating the attendees well and pulling those extra shifts or
duties you didn't anticipate (thanks James). Also put your "people-person" types at the
registration desk where they will likely be needed the most. More personable people will be able
to sell t-shirts and so forth much more easily (thanks Karen). Finally, thank your volunteers.
Everybody likes to be told they've done a good job (thanks everyone else).
Another seemingly weird thing we did was to make our volunteers pay for the honor to work our
event. It seems odd, but it worked. The idea was to have them show us they weren't going to
volunteer and then back out on us at the last minute. In exchange for their $30, they got a polo
shirt and were able to see all the presentations at a lower price than anyone else. And the cash
flow didn't hurt either. While we didn't mandate this for the organizers, it wouldn't be a bad idea.
However, all the organizers did have to pay for their own shirts and many loaned hundreds of
dollars to the effort.
Linus, Tove and Patricia meet Zeph Hull, a showcase volunteer. - Photo by Amy Ayers
Coordinate Vendors
Organize your vendor team so everybody knows which person is calling what company but only
one person is calling each. It is nice for everyone to know the status of a potential vendor. It is
not nice to have 3 separate people make 3 separate cold calls to the same potential vendor.
When contacting vendors, use the phone as your primary means of communications and not
e-mail. While it seems e-mail would work, it is human nature to give it a much lower priority
than a phone call. We found many companies that ignored our e-mail's responded quite
positively to our phone calls.
One of the things we should have done sooner was bill the vendors. We charged each vendor
$400 for a booth and sent them an invoice. While we were expecting one week turn turnarounds
on payment, the business world doesn't work that way. In many cases, paperwork and payments
can take up to 30 days to get through the accounting offices of some companies.
Get People To Talk
We solicited for speakers and presenters over the comp.os.linux.announce news group. This had
to be done multiple times, but eventually the offers started rolling in. We also drew upon some
local talent. And in many cases, the vendors also wanted to give presentations.
Getting speakers to volunteer was the easy part. Getting them to the Showcase was the difficult
part. We had to solicit money from sponsoring companies and the vendors in order to pay for the
travel and lodging expenses for Linus Torvalds, Eric Raymond, David Miller, Richard
Henderson, Miguel de Icaza, and the rest of the crew (and we still owe a debt of gratitude to
Digital and Caldera for all they did in this department).
Once the money was appropriated, travel plans and hotel accommodations were made - at least
that's how it works in the ideal world. A lot of the travel costs were floated on the credit cards of
organizers until they could be reimbursed. Do make plane reservations and travel arrangements
as far ahead of time as possible; you can save on air fare that way.
Work The System
This involves taking advantage of perks and getting the extras out of the people with whom you
are doing business. For example, we decided to also rent some conference rooms at the Days Inn
which was just next store to The Inforum. These conference rooms were used for Birds Of A
Feather sessions and impromptu meetings by our attendees. In order to secure a good price on
the room rental, we made an agreement with the hotel management that we would guarantee they
got a certain number of room bookings based on our event. We then set-up that hotel as our
"Official" hotel and asked most of our out-of-town guests to try the Days Inn first. In addition,
our attendees were able to get a reasonable rate at a downtown hotel. Our guest speakers were
also booked there.
Genie Travel
also became our "Official" travel agent. Genie gave us a certain percentage on
every flight booked through them, and their air fares were very reasonable. Although we didn't
take advantage of this until very late in the game, it would be very advantageous for us to do it
again. Genie Travel uses Linux in their day-to-day operations and probably would be very happy
to repeat this arrangement with another Linux event.
Another good idea would be to solicit the help of other Linux users groups. Often other users
groups that are geographically close by may be able to help. Be sure to get them in on it early in
the planning stage. For instance, we solicited SALUG (Southern Alabama) and CHUGALUG
(Athens, GA), albeit at the last minute. Coordinating with other users groups also insures that
the Linux community isn't throwing a trade show every month in towns only 100 miles apart
(this stretches the resources of the Linux vendors and the enthusiasm these shows generate)..
One last thing that can help is to have a Sugar-Daddy. In our case it was Linux International.
Jon "Maddog" Hall of Linux International helped get us credit through which we were able
secure our lease on the rooms at The Inforum. If you ask him nicely, he may do the same for
you.
Have Fun
Keep in mind that organizing such an event is very hard word and requires a lot of time. We
estimate over 2000 man hours were spent by ALE members putting together our show. But with
any luck, your user group will be able to pull off a grand Linux event. And remember, have fun.
Don't hold your trade show to make money. Do it to spread the word of Linux and to cavort with
other like-minded Linux hobbyists.
Finally, we'd like to thank all our volunteers, vendors, speakers, and organizers for helping out
with the Atlanta Linux Showcase. If you are interested in any videos of the presentations at the
1997 Atlanta Linux Showcase or t-shirts and polo shirts, please visit our web site at
http://www.ale.org/showcase/. And if you have any questions, please feel free to send us e-mail
at ale-expo@cc.gatech.edu.
Greg Hankins hangs out with Maddog and David Hamm. - Photo by Amy Ayers
Copyright © 1997, Andrew Newton
Published in Issue 19 of the Linux Gazette, July 1997
"Linux Gazette...making Linux just a little more fun!"
Using Python to Generate HTML Pages
Introduction
I have waited for a long time to set up my own Web site, mostly
because I didn't know what to put there that others may want to
see. Then I got an idea. Since I'm an avid reader and an aviation
enthusiast, I decided to create pages with a list of aviation books I
have read. My initial intention was to write reviews for each book.
Setting up the pages was easy to start with, but as I added more books
the maintenance became tedious. I had to update couple of indices with
the same data and I had to sort them by hand, and alphabetizing was
never my strong suit. I needed to find a better way.
Around the same time I became interested in the programming language
Python and it seemed that Python would be a good tool to automatically
generate the various HTML pages from a simple text file. This would
greatly simplify the updates of my book pages, as I would only add one
entry to one file and then create complete pages by running a Python
script.
I was attracted to Python for two main reasons: it's very good at
processing strings and it's object oriented. Of course the fact that
Python interpreter is free and that it runs on many different systems
helped. At first I installed Python on my Win95 machine, but I just
couldn't force myself to do any programming in the Windows
environment, even in Python. Instead I installed Linux and moved all
my Web projects there.
The Problem
The main goal of the program is to generate three different book
indices, by author, by title and by subject, from a single input
file. I started by defining the format of this file. Here is what a
typical entry describing one book looks like:
title: Zero Three Bravo
author: Gosnell, Mariana
subject: General Aviation
url: 3zb.htm
# this is a comment
Each line starts with a keyword (eg. "title:" or "author:") and is
followed by a value that will be shown in the final HTML
page. Description of each book must start the "title:" line, there
must be at least one "author:" tag, and the "url:" entry points to a
review of the book, if there is one.
Since Python is object-oriented we begin program design by
looking for "objects". In a nutshell, object oriented (OO) programming
is a way to structure your code around the things, that is "objects",
that the program is working with. This rather simple idea of
organizing software around what it works with (objects), rather than
what it does (functions), turns out to be surprisingly powerful.
Within an OO program similar objects are grouped into "classes" and the
code we write describes each class. Objects that belong to a given
class are called "instances of the class".
I hope it is pretty obvious to you that since the program will
manipulate "book" objects, we need a Python class that will represent
a single book. Just knowing this is enough to let us suspend design
and write some code.
The Book Class
Before we start looking at the code we need to consider briefly how
Python programs are organized. Each program consists of a number of
modules, each module is contained in a file (usually named with the
extension ".py") and the name of the file (without the ".py") serves
as the module name. A module can contain any number of routines or
classes. Typically things that are related are kept in one module. For
example, there is string module that contains functions that
operate on strings. To access functions or classes from another module
we use the import statement. For example the first line of
the Book module is:
from string import split, strip
which says that the routines split and strip are
obtained from the strings module.
Next, I have to point out few syntactic features of Python that are
not immediately obvious the code. The most important is the fact that
in Python indentation is part of the syntax. To see which statements
will be executed following an "if", all you need to look at is
indentation - there is no need for curly braces, BEGIN/END
pairs or "fi" statements.
Here is a typical "if" statement extracted from the set_author
routine in the Book class:
if new_author:
names = split (new_author, ",")
self.last_name.append (strip (names[0]))
self.first_name.append (strip (names[1]))
else:
self.last_name = []
self.first_name = []
The three statements following the "if" are executed if "new_author"
variable contains a non-null value. The amount of indentation is not
important, but it must be consistent. Also note the colon (":") which
is used to terminate the header of each compound statement.
The Book class turns out to be very simple. It consists
of routines that set the values for author, title, subject and the URL
for each book. For example, here is the set_title routine:
def set_title (self, new_title):
self.title = new_title
The first argument to the "set_title" method (that is a routine which
belongs to a class) is "self". This argument always refers to the
instance to which the method is applied. Furthermore, the attributes
(i.e. the data contained in each object) must be qualified with "self"
when referenced within the body of a method. In the example above the
attribute "title" of a "Book" object is set to value of "new_title".
If in another part of a program we have variable "b" that references an
instance of a "Book" class this call would set the book's title:
b.set_title ("Fate is the Hunter")
Note that the "self" argument is not present in the call,
instead the object to which the method is applied (i.e. the object
before the ".", "b" above) becomes the "self" argument.
At this point a reasonable question to ask is "Where do the objects
come from?" Each object is created by a special call that uses the
class name as the name of a function. In addition a class can define a
method with the name __init__ which will automatically be
called to initialize the new object's attributes (in C++ such a
routine is called a constructor).
Here is the __init__ routine for the Book class:
def __init__ (self, t="", a="", s="", u=""):
#
# Create an instance of Book
#
self.title = t
self.last_name = []
self.first_name = []
self.set_author (a)
self.subject = s
self.url = u
The main purpose of the above routine is to create all the attributes
of the new "Book" object. Note that the arguments to "__init__" are
specified with default values, so that the caller needs only to pass the
arguments that differ from the default.
Here are some examples of calls to create "Book" objects:
a = Book()
b = Book ("Fate is the Hunter")
c = Book ("Some book", "First, Author")
There is one small complication in the "Book" class. It is possible
for a book to have more than one author. That's why the attributes
"first_name" and "last_name" are actually lists. We'll look more at
lists in the next section.
The complete Book class is show in
Listing #1. To test the class we add a little piece of code at the end
of the file to test if the code is running as __main__ routine,
that is execution started in this file. If so, the code to test the Book
will run.
The Book_List Class
Once the Book is tested we can go back to designing. The next
obvious object is a list which will contain all the "book"
objects. For the purposes of our program we have to be able to create
the book list from the input file and we have to sort the books in the
list by author, title or subject. Sorted list will then be used as
input into the code that actually generates HTML pages.
As it turns out one of Python's built-in data structures is a list. Here is
a snippet of code showing creation of a list and addition of some items
(this example was produced by running Python interactively):
Python 1.4 (Dec 18 1996) [GCC 2.7.2.1]
Copyright 1991-1995 Stichting Mathematisch Centrum, Amsterdam
>>> s = []
>>> s.append ("a")
>>> s.append ("hello")
>>> s.append (1)
>>> print s
['a', 'hello', 1]
Above we create a list called "s" and add three items to it. Lists
allow "slicing" operations, which let you pull out pieces of a list by
specifying element numbers. These examples illustrate the idea:
>>> print s[1]
hello
>>> print s[1:]
['hello', 1]
>>> print s[:2]
['a', 'hello']
>>> print s[0]
a
s[1] denotes the second element of the list (indexing starts
at zero), s[1:] is the slice from the second element to the
end of the list, s[:2] goes from the start to the third
element, and s[0] is the first item.
Finally, lists have a "sort" operator which sorts the elements according to
a user supplied comparison function.
Armed with the knowledge of Python lists, writing the Book_List class
is easy. The class will have a single attribute, "contents", which will be a
list of books.
The constructor for the Book_List class simply creates a
"contents" attribute and initializes it to be an empty list. The
routine that parses the input file and creates list elements is called
"make_from_file" and it begins with the code:
def make_from_file (self, file):
#
# Read the file and create a book list
#
lines = file.readlines ()
self.contents = []
The "file" argument is a handle to an open text file that contains the
descriptions of the books. The first step this routine performs is to
read the entire file into a list of strings, each string representing
one line of text. Next, using Python's "for" loop we step through this
list and examine each line of text:
#
# Parse each line and create a list of Book objects
#
for one_line in lines:
# It's not a comment or empty line
if (len(one_line) > 0) and (one_line[0] != "#"):
# Split into tokens
tokens = string.split (one_line)
If the line is not empty or is not a comment (that is the first
character is not a "#") then we split the line into words, a word
being a sequence of characters without spaces. The call "tokens =
string.split (one_line)" uses the "split" routine from the "string"
module. "split" returns the words it found in a list.
if len (tokens) > 0:
if (tokens[0] == "title:"):
current_book = book.Book (string.join (tokens[1:]))
self.contents.append (current_book)
elif (tokens[0] == "author:"):
current_book.set_author (string.join (tokens[1:]))
elif (tokens[0] == "subject:"):
current_book.set_subject (string.join (tokens[1:]))
elif (tokens[0] == "url:"):
current_book.set_url (string.join (tokens[1:]))
The first token (i.e. word) on the line is the keyword that tells us
what to do. If it is "title:" then we create a new Book
object and append it to the list of books, otherwise we just set the
proper attributes. Note that the remaining tokens found on each line
are joined together into a string (using "string.join" routine). There
is probably a more efficient way to code this, but for my purposes
this code works fast enough.
The other interesting parts of the Book_List class are the sort
routines. Here is how the list is sorted by title:
def sort_by_title (self):
#
# Sort book list by title
#
self.contents.sort (lambda x, y: cmp (x.title, y.title))
We simply call "sort" routine on the list. To get proper ordering we
need to supply a function that compares two Book objects. For
sorting by title we have to supply an anonymous function, which is
introduced with the keyword "lambda" (those of you familiar with Lisp,
or other functional languages should recognize this construct). The definition:
lambda x, y: cmp (x.title, y.title)
simply says that this is a function of two arguments and function result comes
from calling the Python built-in function "cmp" (i.e. compare) on the "title"
attribute of the two objects.
The other sort routines are similar, except that in "sort_by_author" I
used a local function instead of a "lambda", because the comparison
was little more complicated - I wanted to have all the books with the
same author appear alphabetically by title.
Generating Pages:
Now that we have constructed a list of books, the next step is to create
the HTML pages. We begin by creating a class, called Html_Page, that
generates basic outline of a page and then we extend that class to create
the titles, authors and subjects pages.
The idea that existing code can be extended yet not changed is the
second most import idea of OO programming. The mechanism for doing
this is called "inheritance" and it allows the programmer to create a
new class by adding new properties to an old class and the old class
does not have to change. A way to think about inheritance is as
"programming by differences". In our program we will create three
classes that inherit from Html_Page.
Html_Page is quite simple. It consists of routines that
generate the header and the trailer tags for an HTML page. It also
contains an empty routine for generating the body of the page. This
routine will be defined in descendant classes. The __init__
routine let's the user of this class specify a title and a top level
heading for the page.
When I first tested the output of the HTML generators I simply printed
it to the screen and manually saved it into a file, so I could see the
page in a browser. But once I was happy with the appearance, I had to
change the code to save the data into a file. That's why in Html_Page
you will see code like this:
self.f.write ("<html>\n")
self.f.write ("<head>\n")
for writing the output to a file referenced by the attribute "f".
However, since the actual output file will be different for each page
opening of the file is deferred to a descendant class.
You can see complete code for Html_Page in
Listing #3.
The three classes Authors_Page, Titles_Page and
Subjects_Page are used to create the final HTML pages. Since these
classes belong together I put them in one module, called books_pages.
Because the code for these is classes is very similar we will only look at
the first one.
Here is how Authors_Page begins:
class Authors_Page (Html_Page):
def __init__ (self):
Html_Page.__init__ (self, "Aviation Books: by Author",
"<i>Aviation Books: indexed by Author</i>")
self.f = open ("books_by_author.html", "w")
print "Authors page in--> " + self.f.name
To start with that the class heading lists the name of the class from
which Authors_Page inherits, mainly Html_Page. Next
notice that the constructor invokes the constructor from the parent
class, by calling the __init__ routine qualified by the class
name. Finally, the constructor names and opens the output file. I decided
not to make the file name a parameter for my own convenience to keep
things simple.
Since the book list is needed for to generate the body of each page I added
a book_list attribute to each page class. This attribute is set
before HTML generation starts.
The generate_body routine redefines the empty routine from
the parent class. Although fairly long, the code is pretty easy to
understand once you know that the book list is represented as an HTML
table and the "+" is the concatenation operator for strings.
In addition to replacing the generate_body routine we also redefine
generate_trailer routine in order to put a back link to the book index
at the bottom of each page:
def generate_trailer (self):
self.f.write ("<hr>\n")
self.f.write ("<center><a href=books.html>Back to Aviation Books Top Page</a></center>\n")
self.f.write ("<hr>\n")
Html_Page.generate_trailer (self)
Notice how right after we generate the back link, we include a call to
parent's generate_trailer routine to finish off the page with
correct terminating tags.
Complete listing for the three page generating classes are found in
Listing #4.
The main line of the entire program is shown in
Listing #5. By now the code there
should be self explanatory.
Summary
As you can see this particular program was not hard to write. Python is
well suited for these types of tasks, you can quickly put together
a useful program with minimal fuss.
After I have got the program to work I realized that its design
is not the best. For example, the HTML generating code could be more
general, perhaps the Book class should generate it's own
HTML table entries. But for now the program fits my purposes, but
I will modify if I need to create other HTML generating applications.
If you like to see the results of this script visit my
book page.
To learn more about Python you should start with the Python Home Page which will point you
to many Python resources on the net. I also found the O'Reilly book
Programming in Python by Mark Lutz extremely helpful.
Finally, any mistakes in the description of Python features are
my own fault, as I'm still a Python novice.
Copyright © 1997, Richie Bielak
Published in Issue 19 of the Linux Gazette, July 1997
"Linux Gazette...making Linux just a little more fun!"
Using SAMBA to Mount Windows 95
Many major universities are now offering network connections to
students in their rooms. This is really a wonderful thing for the
Linux community. Whereas, the majority of student owned computers
on these networks are still running Windows 95, many students are
making the switch to Linux. One thing that newcomers to Linux are
constantly asking is, "Can I access a directory shared by a
Windows 95 computer in the 'Network Neighborhood', and can I
share files to Windows 95 users?" The answer, of course, is YES.
I keep trying to tell them that there is nothing that Linux can
not do, yet they continue to come to me and ask if they can do
this in Linux, or if they can do that. I have never once answered
no.
Samba
To mount a Windows 95 share, we use a program called Samba. Samba
is a program that allows Linux to talk to computers running
Windows for Workgroups, Windows 95, Windows NT, Mac OS, and Novel
Netware. Samba even allows you to share a printer between
computers using these different operating systems. Samba comes
with most distributions of Linux, but if you do not have it
installed, you can obtain a copy from the Samba home page at
http://lake.canberra.edu.au/pub/samba/.
Mounting Windows 95 Shares
The first thing you will probably want to do, is check to see
what directories are shared on the computer you are trying to
mount off of. To do this type smbclient -L computername. This
will list all the directories shared by the machine. To mount the
directory, we use the command smbmount. Smbmount can be a little
tricky though. I have created a script, named smb, that allows
users to mount drives using smbmount, with relative ease.
#usage smb computername sharename
#!/bin/sh
if [ $UID = 0 ]; then
if [ ! d /mnt/$1 ]; then
mkdir /mnt/$1
fi
#You may want to add the -u option here also if you need to
#specify a login id (ie: mounting drives on Windows NT)
/usr/sbin/smbmount //$1/$2 /mnt/$1 I $1 c etc
else
if [ ! d ~/mnt/ ]; then
mkdir ~/mnt/
fi
if [ ! d ~/mnt/$1 ]; then
mkdir ~/mnt/$1
fi
#You may want to add the -u option here also if you need to
#specify a login id (ie: mounting drives on Windows NT)
/usr/sbin/smbmount //$1/$2 ~/mnt/$1 I $1 c etcfi
To execute this script you simply type smb followed by the name
of the computer you are mounting off of, and then the directory
you wish to mount (ex. smb workstation files). If you are root,
the script creates a directory in /mnt by the same name as the
computer, and mounts the directory there. For any other user, the
script makes a directory in the users home directory named mnt.
In that directory it makes another directory by the same name as
the computer and mounts the share there.
Sharing files with Windows 95
Now to share a file. This also is not too difficult. To share a
directory you need to edit /etc/smb.conf. By default, Samba
shares users' home directories, but they are only visible (and
accessible) to the owner. This means that the person accessing
the share should be logged into Windows 95 with the same loginid,
as they use to log into your Linux box.
Let's say you want to let 'bob' access the directory
'/shares/files', and you do not want anyone else to access it. To
do this, add these lines to your /etc/smb.conf file.
[bobsfiles]
comment = files for bob
path = /shares/files
valid users = bob
public = no
writable = yes
printable = no
- indicates the name the directory will be shared under.
- is a comment that can be displayed in the Windows 95
Network Neighborhood.
- lists the directory on your computer that will be shared
- when set to yes allows users to access the directory with
guest privileges.
- indicates whether or not the user has write permissions to
the indicated directory
- when set to yes allows users to spool print jobs from that
directory
More examples on sharing files can be found in the default
smb.conf file. For more help on setting up this file, see the
Samba web page, or type man smb.conf.
More cool Samba stuff
If a Windows 95 user on your network is running winpopup (an
instant massaging program), you can send them a winpopup message
using Samba. To do this just type
smbclient -M computername
message_text
.
Copyright © 1997, Jonathon Stroud
Published in Issue 19 of the Linux Gazette, July 1997
Copyright © 1997 Specialized Systems Consultants, Inc.
For information regarding copying and distribution of this material see the
Copying License.
Contents:
About This Month's Authors
Larry Ayers
Larry Ayers lives on a small farm
in northern Missouri, where he is currently engaged in building a
timber-frame house for his family. He operates a portable band-saw mill,
does general woodworking, plays the fiddle and searches for rare
prairie plants, as well as growing shiitake mushrooms. He is also
struggling with configuring a Usenet news server for his local ISP.
Jim Dennis
Jim Dennis
is the proprietor of
Starshine Technical Services.
His professional experience includes work in the technical
support, quality assurance, and information services (MIS)
departments of software companies like
Quarterdeck,
Symantec/
Peter Norton Group, and
McAfee Associates -- as well as
positions (field service rep) with smaller VAR's.
He's been using Linux since version 0.99p10 and is an active
participant on an ever-changing list of mailing lists and
newsgroups. He's just started collaborating on the 2nd Edition
for a book on Unix systems administration.
Jim is an avid science fiction fan -- and was
married at the World Science Fiction Convention in Anaheim.
John Eikenberry
John currently lives in Athens, GA where he is both a student and an
employee of the University of Georgia. He is working on his masters thesis
in artificial intelligence while working full time as a system administration
and programmer for the College of Education. Prior to his coming to Athens,
John studied psychology and philosophy ending with a Masters of Philosophy
from the University of Toledo. He has been using Linux since 1994 and
maintains the Linux Ai/Alife
mini-Howto.
John Gatewood Ham
John Ham was born June 10, 1964, in Florence, Alabama.
He has a
B.S., Mathematics, from The University of the South, Sewanee, TN and an
M.S., Computer Science, from The University of Missouri-Rolla, Rolla, MO.
He is currently working as an Instructor in the Computer Science Department
at Burapha University, Bang Saen, Cholburi, Thailand.
He teachs in English -- he does not speak Thai. He lives in Thailand, because his
wife is Thai and did not wish to live in the United States.
His Home Page
Michael J. Hammel
Michael J. Hammel,
is a transient software engineer with a background in
everything from data communications to GUI development to Interactive Cable
systems--all based in Unix. His interests outside of computers
include 5K/10K races, skiing, Thai food and gardening. He suggests if you
have any serious interest in finding out more about him, you visit his home
pages at http://www.csn.net/~mjhammel. You'll find out more
there than you really wanted to know.
Evan Leibovitch
Evan is a Senior Analyst for Sound Software of Brampton, Ontario, Canada.
He's installed almost every kind of Unix available for Intel systems over
the past dozen years, and this year his company became Canada's first
Caldera Channel Partner.
Mike List
Mike List is a father of four teenagers, musician, printer (not
laserjet), and recently reformed technophobe, who has been into computers
since April,1996, and Linux since July.
Andy Newton
Andy Newton is a Java programmer for Automated Logic Corporation and has
been an active member of the Atlanta Linux Enthusiasts for two years.
When not playing with computers, he enjoys running, backpacking, political
banter and spending time with his fiancee, Karen.
His Home Page
Justin Seiferth
When Justin's
not busy improving our nation's information boreen, he's at home hacking
various projects.
If you are cut off by a silver coupe
with New Mexico plates on the roads around our nation's capital, feel free
to wave hello! Justin and his family will be making their annual
sojourn to relatives in Ireland
during July- he'd like to hear from fellow Linux users over there.
Cliff Serutine
Cliff Seruntine is a writer and an electronics and computer technician,
web designer and all around hacker. He lives in Alaska with his family
of four where they fight a never-ending battle against the evil computer
assimilators and spend their weekends salmon fishing. He'd love to have
you over to visit. Meet him at http://www.micronet.net
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.
My assistant, Amy Kukuk, did all the work again this month.
She's so good to me. Thank you, Amy.
I'm going on vacation from July 3 to July 13, and I am truly looking
forward to it. I've been working much too hard since taking over as Editor
of Linux Journal, and a week or so with no work in my thoughts is
going to be a much needed break. Riley and I are flying to Southern
California to visit his dad--the esteemed UCLA Professor Emeritus, Dr.
Ralph Richardson. We also will be visiting my daughter Lara and her
children. Pictures of all my grandchildren are on my home page--they are, of
course, the most beautiful and most intelligent grandkids in the world. I
am very proud of them, as you can see.
Have fun!
Marjorie L. Richardson
Editor, Linux Gazette gazette@ssc.com
Linux Gazette Issue 19, July 1997, http://www.ssc.com/lg/
This page written and maintained by the Editor of Linux Gazette,
gazette@ssc.com
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