From: steved@lion.inmos.co.uk (Stephen Doyle)
Subject: Re: Transputer simulator for SUN
Reply-To: steved@inmos.co.uk (Stephen Doyle)
Organization: INMOS Limited, Bristol, UK.
Date: Fri, 2 Oct 1992 09:06:07 GMT

In Article 61 of comp.sys.transputer:
alf@uni-paderborn.de (Alf Wachsmann) writes

> The main hint was given by Iain Phillips (Iain.Phillips@cs.man.ac.uk)
> who suggested to use the Toolset "isim" simulator.
> 
> This program simulates a T425-Transputer on a SUN and it IS
> possible to simulate great transputer networks if you set
> the UNIX environment variables IBOARDSIZE to something large.
> 
> Additionally you have to declare the memsize in the .pgm-file
> sufficiently large (e.g. SET Root(type, memsize := "T425", 104*mega) ).
> 
> I tried it with a 26 Transputer network without any problems!

The isim program is only a single processor simulation, what you must have
been doing is to configure multiple configuration level processes on a single
processor, isim doesn't mind this as it is trying to simulate the execution
of this as would happen on a real transputer. You might have 26 configuration
level processes in your system but you don't have 26 PROCESSORS defined to
the configurer. Of course with having identical communications instructions on
the transputer whether using internal channels or hard links you should be 
able to assume that a 26 configuration level process system 
will easily spread over a multiprocessor system.

also in Article 65 of comp.sys.transputer:
luigi@pical2.uucp (Luigi Rizzo) writes

> Recently there has been some discussion on isim. As pointed out by some
> users, the Unix (well, SUN) version has some advantages over the real
> thing because it can emulate a system with a lot of memory (if I'm not
> wrong, limited only by swap space ?); I don't think the
> Transputer-based isim (the one shipped with MSDOS systems) has this
> ability.

isim is a functionally similar simulation of the transputer, there is no
guarantee that the results of running on the transputer will agree with the
results of running on isim (although we have tried to make isim as good as
possible). isim is a tool for debugging low level software and in this
case, and this case alone isim has an advantage over the transputer, also
it is considerably slower than any real transputer (you might get a few 10s of
K transputer instructions/sec). For anyone who wants to run a transputer
application they should run on real transputer hardware, this gets the customer
accuracy of execution model and execution speed.
In the IMSD7214 and IMSD7205 products isim runs on a transputer board and
is limited to the physical memory available - this overcomes the standard
hard limit of MS-DOS 640k memory limits. If you had a 104MB TRAM isim would
quite happily let you use this memory.

> but we'd still like to get/buy a version of isim running on a
> DECstation. Is such a thing available ...

NO

> As an aside, it would be VERY NICE of Inmos if the source for isim were
> made publicly available, same as they did with their servers and other
> stuff (e.g. the 'check' program). I don't think this would stop people
> from buying Transputers!

If anyone wants to develop a public domain transputer simulator they are 
quite at liberty to do so. INMOS do not have a policy of giving away 
valuable intellectual property (especially that containing proprietary 
information). You have already demonstrated that the availability of isim 
has had some effect in stopping people from buying transputers.


regards,

Steve

Steve Doyle, Software Marketing, INMOS Ltd   | Tel +44 454 616616
1000 Aztec West                              | 
Almondsbury                                  | UK: steved@inmos.co.uk
Bristol BS12 4SQ, UK                         | US: steved@inmos.com
Newsgroups: comp.sys.transputer