From: rracine@draper.com (Roger Racine)
Subject: Re: tasking in Ada and Annex D question
Date: 1999/02/02
Date: 1999-02-02T00:00:00+00:00 [thread overview]
Message-ID: <rracine.8.0008248D@draper.com> (raw)
In-Reply-To: 7963h1$a6h$1@nnrp1.dejanews.com
In article <7963h1$a6h$1@nnrp1.dejanews.com> robert_dewar@my-dejanews.com writes:
>In article <793jl9$hf@drn.newsguy.com>,
> nabbasi@earthlink.net wrote:
>> 1. How could FSU be an Annex D compliant, if one thread
>> will block the other like this? (even though one will
>> expect that doing an IO message will cause a task to
>> yield the CPU).
>Annex D requires run till blocked semantics, and forbids
>any kind of time slicing.
>You say that you "expect" that doing an IO message will
>cause a task to yield the CPU.
>You can expect anything you like, but you read no such
>requirement in the RM, because there is no such
>requirement!
In the Ada 95 Rationale, the last paragraph of section D.2.1 states:
" Another anticipated application requirement is for time slicing.
Implementation-defined time-slicing schemes may conform to this specification
by modifying the active or base priority of a task, in a fashion similar to
that outlined for EDF scheduling."
I re-read the Annex and can find nothing to support your contention that it
requires run till blocked semantics, with your definition of "blocked". It
seems that "task dispatching points" are completely implementation defined
(D.2.2.18).
I am in agreement with those who want tasks to block on I/O calls. An I/O
call must be considered a dispatching point, IMHO.
Roger Racine
next prev parent reply other threads:[~1999-02-02 0:00 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
1999-01-31 0:00 tasking in Ada and Annex D question nabbasi
1999-02-01 0:00 ` Dr. Hubert B. Keller
1999-02-02 0:00 ` robert_dewar
1999-02-02 0:00 ` Roger Racine [this message]
1999-02-02 0:00 ` robert_dewar
1999-02-03 0:00 ` Nick Roberts
1999-02-03 0:00 ` Frank Mueller
1999-02-03 0:00 ` Frank Mueller
1999-02-03 0:00 ` Roger Racine
1999-02-03 0:00 ` Tom Moran
1999-02-02 0:00 ` Markus Kuhn
1999-02-02 0:00 ` robert_dewar
1999-02-02 0:00 ` Markus Kuhn
1999-02-02 0:00 ` Niklas Holsti
1999-02-03 0:00 ` Ehud Lamm
1999-02-03 0:00 ` robert_dewar
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