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Re: CSP and Petri nets?

A collagure of mine when I was at Sheffield Poly did a lot of work in this
area.  he is called Geoff Cutts and Sheffield Poly is now called Sheffield
Hallam University


Professor JM Kerridge		tel   	+(0) 131 455 4395
Department of Computer Studies	fax 	+(0) 131 455 4552
Napier University		email 	j.kerridge@xxxxxxxxxxxxxxxx
219 Colinton Road               web     http://www.dcs.napier.ac.uk/~jmk
EH14 1DJ

On Fri, 11 Jun 1999, P.H.Welch wrote:

> Dyke,
> >   What are the relative strengths of and relations between CSP and
> > Petri nets?
> I've always steered well clear of Petri nets.  In their strict form,
> they give a data-driven parallelism (nodes fire only when input tokens
> arrive from *all* sources) that is always deterministic.  To model
> an ALT (say) that's listening and reacting to just one of many input
> sources, you have to arrange dummy tokens to be continually moving.
> I've always found them bewildering - especially when compared with
> occam-style network diagrams.  Petri net nodes are simply modelled
> by an occam process, but not vice-versa.  My feeling (I've never ever
> done it!) is that you have to go to a lot of trouble to build a Petri
> net model of an event-reacting CSP design ... and I don't see the
> end benefit from all that trouble.  Petri nets have well-defined
> mathematical properties, but so does CSP ... I don't know how Petri
> net analysis tools compare with those from CSP nor whether they can
> deliver as many useful properties ... need input from proper Petri
> experts ...
> Peter.