From: bobduff@world.std.com (Robert A Duff)
Subject: Re: ADA task
Date: 1996/09/20
Date: 1996-09-20T00:00:00+00:00 [thread overview]
Message-ID: <Dy0AH1.BM@world.std.com> (raw)
In-Reply-To: 324159A2.6220@watson.ibm.com
In article <324159A2.6220@watson.ibm.com>,
Norman H. Cohen <ncohen@watson.ibm.com> wrote:
>The Ada-95 Real-Time Annex defines certain "metrics" of real-time
>performance, including metrics of the performance of both kinds of delay
>statement. (See RM Section D.9.) The Annex requires implementations
>claiming conformance to the Annex to document their performance with
>respect to these metrics as well as with respect to several
>nonquantitative aspects of real-time performance.
Yeah, but let's not get carried away with this. Ada doesn't define
performance, in general, and neither does any other language I know of.
How long does "X := Y;" take, when X and Y are of type Integer? The RM
doesn't say. So why are we so worried about the fact that delay
statments might take too long? Suppose the Ada compiler makes "X := Y;"
take 1 second. Is that acceptable? Well, no, but it has nothing to do
with the RM. Likewise, suppose a task's delay expires, and the run-time
system doesn't notice that fact for 1 second. Is that acceptable? No,
but it's not the fault of the language. It's the fault of the Ada
implementation, or maybe the OS it's running on top of. (I'm appalled
that certain OS's can't measure time more accurately than 1/18 second!)
- Bob
next prev parent reply other threads:[~1996-09-20 0:00 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
1996-09-17 0:00 ADA task Marin David Condic, 407.796.8997, M/S 731-93
1996-09-19 0:00 ` Norman H. Cohen
1996-09-20 0:00 ` Robert A Duff [this message]
-- strict thread matches above, loose matches on Subject: below --
1996-09-18 0:00 tmoran
1996-09-17 0:00 Marin David Condic, 407.796.8997, M/S 731-93
1996-09-20 0:00 ` Robert A Duff
1996-09-11 0:00 Roumen Roupski
1996-09-12 0:00 ` Philip Brashear
1996-09-13 0:00 ` Norman H. Cohen
1996-09-13 0:00 ` Samuel T. Harris
1996-09-14 0:00 ` Robert Dewar
1996-09-14 0:00 ` Samuel T. Harris
1996-09-15 0:00 ` David C. Hoos, Sr.
1996-09-16 0:00 ` Samuel T. Harris
1996-09-16 0:00 ` Norman H. Cohen
1996-09-14 0:00 ` Roumen Roupski
1996-09-16 0:00 ` Norman H. Cohen
1996-09-14 0:00 ` Ken Garlington
1996-09-16 0:00 ` Robert I. Eachus
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