Newsgroups: comp.sys.transputer
From: andyr@wizzy.com (Andy Rabagliati)
Subject: Re: Please help with Occam/tranputers
Organization: W.Z.I.
Date: Thu, 17 Mar 1994 19:35:09 GMT
Message-ID: <CMtqEL.67w@wizzy.com>

In article <1994Mar17.073111.7166@bnr.ca>,
Gene Clendon  <clendon@bnr.ca> wrote:

>I'm having a few problems coming to grips with Occam at the moment.  Can
>anyone help me on this?
>
>When communicating on channels, the process will hold until that
>communication is complete.  If the receiver is expecting more than what
>is sent, it will deadlock.

Communicating processes on the same transputer sychronise at the
message level, not the byte level.

An outputting process that must wait (because the corresponding
input is not ready) leaves no information for the inputting process
as to exactly how much data is output. All that is indicated is
that a message is ready, and it starts here.

The inputting process may input as much as it pleases.

Conversely, if the input gets there first, it merely indicates where
to put the message, not how much to put there. The outputting process
is at liberty to completely trash the inputting process workspace by
outputting too much.

This is why occam has protocols. If you input / output differing
amounts, you are on your own.

Cheers,      Andy.

--
The man pulling radishes	             Andy Rabagliati  andyr@wizzy.com 
pointed the way						    W.Z.I. Consulting
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