From: Brian Drummond <brian@shapes.demon.co.uk>
Subject: Re: Concurrency always is non-deterministic?
Date: Mon, 13 Feb 2012 22:10:48 +0000 (UTC)
Date: 2012-02-13T22:10:48+00:00 [thread overview]
Message-ID: <jhc1p8$sr5$1@dont-email.me> (raw)
In-Reply-To: 3721724.784.1329154891821.JavaMail.geo-discussion-forums@pbcwt9
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
next prev parent reply other threads:[~2012-02-13 22:10 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-02-13 17:41 Concurrency always is non-deterministic? Long Hoàng Đình
2012-02-13 18:04 ` Dmitry A. Kazakov
2012-02-13 19:38 ` Simon Wright
2012-02-13 19:56 ` Bill Findlay
2012-02-14 1:13 ` Simon Wright
2012-02-14 11:29 ` John B. Matthews
2012-02-14 2:34 ` Phil Clayton
2012-02-13 18:06 ` Georg Bauhaus
2012-02-13 19:11 ` Niklas Holsti
2012-02-13 22:10 ` Brian Drummond [this message]
2012-02-14 2:18 ` Phil Clayton
2012-02-14 10:05 ` Erich
2012-02-14 15:00 ` Phil Clayton
2012-02-14 18:23 ` Jeffrey Carter
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