CD-ROM access via Linux (fwd)

Web4Lib Moderator listchek at
Thu Sep 21 16:45:19 EDT 1995

---------- Forwarded message ----------
Date: Thu, 21 Sep 1995 10:36:18 +0100 (BST)
From: Jon Knight <J.P.Knight at>
To: lis-elib at, web4lib at
Subject: CD-ROM access via Linux

[This message is long; if you're not interested in networking CD-ROMs, 
kill the article now.  However I had sufficient interest from both 
mailing lists the last time this was talked about to make me think its 
worthwhile sending it to them.  YMMV.]

You might remember from the beginning of August lots of us Library systems
bods were having a rant about CDROMs on both the lis-elib and web4lib
mailing lists.  I mentioned to several people that one of the biggest
problems at LUT (aside from actually mounting the !$#%^%$ things) is that
all of our networked CD-ROMs are DOS based, running from Novell servers. 
This is a pain as it means that only users with DOS PCs on their desks can
use them unless they go to the library and use the public workstations
(which isn't ideal as those machines are already heavily used by the
students during term time).  People with Macs, UNIX boxes and dumb
terminals were out in the cold.  Even MS-Windoze users have problems with
many of the DOS CD-ROMs due to lack of memory or clashes with local CD-ROM
drives (which are becoming the norm it seems). 

Well, this is just a quick note to let you know that I've been playing
with a possible solution to this problem and as I had quite a lot of mail
on the subject last time, I thought I'd share it with the lists.  Note
that this _isn't_ a production service at LUT yet; I've just got the first
prototype going last night but it looks very promising.  It also has the
big advantage for cash strapped libraries of being free (aside from the
cost of a PC - no pay-per-play software is needed). 

The basic idea to overcome the problem is to use an intermediate machine 
to run the CD-ROM software on that can talk TCP-IP and supports telnet 
connections.  OS/2 had been tried in the past but it wasn't too successful 
(it didn't like the PC hardware we had apparently).  I plumped for using 
Linux, a free UNIX like operating system that runs on ordinary 386/486/586 PC
platforms.  Linux is nice because there is an application called DOSEMU 
that runs as a process on the Linux machine and gives you a DOS shell.  
You can run multiple copies of DOSEMU simultaneously on the Linux machine 
and it seems to give a very good DOS virtual machine.

Once I'd installed Linux (Slackware Release 1.2.8) and DOSEMU (v0.60.3)
(which in my case took a while as I reconfigured the Linux kernel and
accidently broke DOSEMU - duh!) it was then a simple matter of using it to
connect to the Novell servers in the library.  Oh yeah, I forgot to
mention that Linux includes IPX in its kernel as well as IP... :-)  You 
can use the normal and netx.exe DOS programs that you've already 
got for your DOS machines.

Once you can make Novell connections, you're half way there.  You should 
find it pretty easy to fire up your CD-ROM software _as_long_as_ it isn't 
overly graphical.  If it is, it might work fine on the Linux console but 
won't be too hot over telnet.  However lots of DOS CD-ROMs are mainly 
text based and they work fine over telnet, with one proviso; your 
client and its telnet application must support function keys as most of 
the DOS CD-ROMs use them like they're going out of style.

This last point was nearly a showstopper for us; it meant that the 
CD-ROMs could be used from the UNIX machines under X (in fact you can 
even use DOSEMU's xdos to give a nice, coloured output that looks 
identical to a PC screen) but our MS-Windoze and Mac telnets weren't up 
to sending function keys.  This was a bummer as the Macs were the main 
reason for doing this.

Luckily, that all round wonder package, Expect, came to the rescue.  For
those of you who haven't met Expect yet, its an extension to the Tool
Command Language (TCL) that allows you to easily script logins to remote
services.  I've used Expect for years to do interesting things (the first
was to add wrappers round queries to our old BLS OPAC to allow it to be 
access directly from a gopher client) and it gets my vote as a really cool 
package.  All systems managers should have it in their tool box.

I wrote a script that would fire up the DOS emulator, do all the
nitty-gritty Novell logins and drive mappings, launch the CD-ROM software
and get through all the tedious banner pages for the user before putting
the session into interactive mode.  However, this interactive mode made
use of Expect's ability to remap keystrokes from the user into completely
different key sequences sent to the application.  As few of our CD-ROMs
use control keys, I mapped <control>-A to the sequence for <F1>,
<control>-B to <F2>, etc, etc.  I also mapped <control>-Z as an emergency
exit button (some of the CD-ROM software makes it less than clear to the
user how to get out so having a standard quit key is a nice bonus). 

And that is more or less it.  It works from DOS (obviously), MS-Windoze
using Lan Workplace, NCSA Telnet 2.4.19 on Macs (even my PowerBook with no
function keys at all) and from my SS5 UNIX workstation.  I guess it should
work from dumb terminals and anything that can emulate a VT100.  I've done
most of the tests on Global Books In Print from Bowker-Saur sitting in a
SCSI Express Novell server and that works fine.  And best of all we can
now make hyperlinks to the CD-ROMs from the Library's WWW pages (just
ordinary telnet URLs). 

As I say, its still very much a prototype as we've got to get OPTINET
discs working (it doesn't like the version of DOS I loaded into DOSEMU :-(
) and check what kind of load the little 486/33 that is running Linux can 
handle (its got a 230MB HD and 16MB of RAM by the way so its nothing 
special.  We're not talking Windows95 levels of resource gobbling here).  
However for any other systems bods confronting the same problem, I'd say 
``give it a go''.  As the software is all free and available from a major 
archive near you, you've little to lose.

Feel free to email me for more details (sorry, I can't give a URL that you
can try as we've naturally had to limit this to on campus use due to the
licensing requirements of most CD-ROMs).


Jon Knight, Researcher, Sysop and General Dogsbody, Department of Computer
Studies, Loughborough University of Technology, Leics., ENGLAND.  LE11 3TU.
*** If French nuclear weapons aren't harmful, what's the point of them? ***

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