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Re: Priority modeling with CSP?
Jim Davies wrote:
I forgot to add that I think the above identification of priority and time
only applies in an interleaving semantics. Of course, original pure CSP is
based on an interleaving semantics. Indeed, that is one gloss we can give
nowadays to the word "sequential" in the name which we may otherwise think
to be an anachronism.
But when we are modelling a synchronous circuit in full detail,
interleaving semantics is inadequate. But it is possible to add true
concurrency into CSP with very little change including retention of traces.
And, (genuinely!) without wishing to start a debate, but simply
wishing to indicate a divergence in views, I would disagree.
I think that there is good reason for wishing to distinguish such a
notation. Calling it CSP suggests that it has the same (fundamental)
notion of event as CSP, which it most certainly does not.
I take that point. And have sometimes worried about it as well. I call it
HCSP. It look and feels like CSP in almost all respects. And with true
concurrency removed, or parked, it then reverts to CSPP which is very close
to a superset of CSP.
I agree that the extensions are disturbing to someone schooled in
conventional CSP. But the ideas of CSP are remarkably robust with respect
to larger interpretation.
Any suggestions for another name? Deviant_CSP perhaps? :-)
Having said all that, I am not so sure as you that the event model is
*really* different. My events always involve the exchange, and thus the
communication, of information. The fact that some processes are passive can
just be regarded as a choice not to block which, as far as the model is
concerned, they might have done. They are still regarded as having
synchronised - very quickly.
I too don't want to get into an extended debate :-) Also genuinely.
Dr A E Lawrence