From: ncohen@watson.ibm.com (Norman H. Cohen)
Subject: Re: ADA task
Date: 1996/09/16
Date: 1996-09-16T00:00:00+00:00 [thread overview]
Message-ID: <51jnm6$16qc@watnews1.watson.ibm.com> (raw)
In-Reply-To: 51ep6c$cut@nr1.ottawa.istar.net
In article <51ep6c$cut@nr1.ottawa.istar.net>, "Roumen Roupski"
<Roumen.Roupski@Pika.Ca> writes:
|> In your example above you use Calendar package. I saw GNAT has
|> Ada.Real_Time package. Should I use it instead of Calendar?
Old habits die hard. Yes, you should.
Ada.Real_Time is provided by every Ada-95 compiler that supports the
Real-Time Annex and is guaranteed to provide more accurate time
measurement than Ada.Calendar is guaranteed to provide. The delay-until
statement works not only with type Ada.Calendar.Time, but also with type
Ada.Real_Time.Time.
Paragraph D.9(13) of the Ada-95 RM requires an implementation supporting
the Real-Time Annex to guarantee an upper bound on the difference between
the delay time specified in the delay-until statement and the time at
which execution of the delayed task actually resumes. This can be used
to address Ken Garlington's concerns about guaranteeing on-time execution
of a periodic piece of work. (Careful analysis, such as rate-monotonic
scheduling, is necessary to ensure that the processor will be available,
i.e., that all other tasks of equal or higher priority will be suspended,
when a delay expires; the guarantees in paragraph D.9(13) ensure that
under those conditions a sleeping task awakens quickly when the delay
expires.)
--
Norman H. Cohen ncohen@watson.ibm.com
next prev parent reply other threads:[~1996-09-16 0:00 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
1996-09-11 0:00 ADA task 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 ` Ken Garlington
1996-09-14 0:00 ` Roumen Roupski
1996-09-16 0:00 ` Norman H. Cohen [this message]
1996-09-16 0:00 ` Robert I. Eachus
-- strict thread matches above, loose matches on Subject: below --
1996-09-17 0:00 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
1996-09-17 0:00 Marin David Condic, 407.796.8997, M/S 731-93
1996-09-20 0:00 ` Robert A Duff
1996-09-18 0:00 tmoran
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