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From: Brian Drummond <brian@shapes.demon.co.uk>
Newsgroups: comp.lang.ada
Subject: Re: Concurrency always is non-deterministic?
Date: Mon, 13 Feb 2012 22:10:48 +0000 (UTC)
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Date: 2012-02-13T22:10:48+00:00
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On Mon, 13 Feb 2012 09:41:31 -0800, Long Hoàng Đình wrote:

> The author of this post said so. If Ada were non-deterministic at
> concurrency, I guess it couldn't be real-time, right?
> 
> http://ghcmutterings.wordpress.com/2009/10/06/parallelism-concurrency/
> 
> Please let me know your opinions about that post.

As a counterexample, the VHDL language's model of concurrency is 
deterministic. 

(In the terms of the article, it is a side-effecty language, but there is 
a two-stage execution model where the side effects happen as "postponed 
assignments" which are scheduled after all the concurrent processes have 
suspended. It follows that the processes have to have well defined 
suspend intervals; these are guaranteed in hardware by static timing 
analysis. After the assignments, the next scheduling event restarts some 
or all processes)

So I can't entirely agree with the article.

- Brian