[TUHS] Emulators

José R. Valverde jrvalverde at cnb.uam.es
Mon Aug 9 23:16:43 AEST 2004

On Mon, 9 Aug 2004 15:22:28 +0400 (MSD)
Sergey Lapin <slapin at drevlanka.ru> wrote:
> Hi all!!!
> While educating people some unix stuff (at time, spare from work as 
> admin), I have a need for making some simple UNIX-like  environment for 
> people to try to type some simple commands. Now I need to make it possible 
> to do it remotely. Are there any emulators, that are capable to run V5/6/7 
> or (better) 4.2BSD, and accessible by telnet or something like that?
> Additional thing I need is vi, any emulator that is capable of
> running vi could make me happy!!! 
I think you can do this with SIMH. Various scenarios come to mind:
UNIX v5/6/7
	AFAIK you don't have support for IP on these by default, hence

	- separate instances for each user: this requires multiplying
the UNIX disks for each user, hence requires more space. OTOH, starting
the system reduces to writing a script to start simh and calling it
from the login script

	- many users sharing the same instance: there's only one copy of
the system and everybody logs-in on it, saves space, but takes more work.
You can set up simh to attach a number of serial lines to telnet ports
and ask people to telnet to those ports. This is akin to coming into a
computer room and looking for a free terminal (only you can't see until
you try). This may be enhanced substituting the login script of a normal
account by a new one that tries the ports in turn looking for a free one

4.x BSD, ULTRIX 3.1, 2.11bsd
	I've been able to run 4.3 from TUHS images without any problem.
I configured the network following the standard procedures and using a
valid IP, and it works as a standalone machines allowing incoming/outgoing
IP connections. No problem here.

> Emulation is needed because of unlimited virtualization possibility, 
> unlimited variation of configurations, and, of course, zero time for 
> recover after root errors. simh runs fast 60 instances on P233.
> But now I need vi :(

That's a toughie. VI is big and demands a lot from the system (on ancient
machines). You'll need to configure them with extra memory.. It does not
depend on the emulator itself, mind you, but on the operating system 
providing the required support libraries. 

There are small-footprint editors around, but most I found require curses
so you'd need to port curses back to these ancient systems.

There is a simplistic vi-clone called s whose source code appeared in "A 
Software Tools Sampler", by Web Miller. You can get the sources from his

The book says it worked on 4.x BSD. I was back-porting it to V7 just
before holidays but found some problems and left it until I find more
spare time to work on it.

If you can get it to work or find another one that works, let us know, I
for one would welcome it.

	These opinions are mine and only mine. Hey man, I saw them first!

			    José R. Valverde

	De nada sirve la Inteligencia Artificial cuando falta la Natural

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