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From: tmoran@acm.org
Subject: Re: Timing Block of GNAT code in milliseconds
Date: Fri, 29 Apr 2005 15:24:27 -0500
Date: 2005-04-29T15:24:27-05:00	[thread overview]
Message-ID: <qLednUYN74JmCu_fRVn-iA@comcast.com> (raw)
In-Reply-To: j44ad3vimbbd$.1ugquvdmos17o.dlg@40tude.net

> 2. Real_Time.Clock time is valid no longer next system boot.
Why?  You could surely have a single black box located, say, in Greenwich
England, which could be queried for time over the internet.  Then you make
a body for Real_Time.Clock that does that query to provide a time.  All of
your programs on all of your distributed programs use the same library so
they query the same box and get the same time.  The duration of a call to
such a Real_Time.Clock might be long and might be variable, but that's
true to some extent just running on a single multi-tasking machine.  If
you want something faster and less variable, have each machine read from a
time continually transmitted over a fiber optic cable from a central
source.  There's no requirement that Ada.Real_Time use whatever low
quality clock is provided by the particular computer it's running on.
That just happens to be simpler, and adequate for most uses.



  reply	other threads:[~2005-04-29 20:24 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-04-21 13:28 Timing Block of GNAT code in milliseconds markp
2005-04-21 18:00 ` tmoran
2005-04-21 18:53   ` markp
2005-04-21 19:40     ` Marc A. Criley
2005-04-21 19:44     ` Simon Wright
2005-04-22  1:00   ` Steve
2005-04-23  5:39     ` Simon Wright
2005-04-23 17:49       ` Steve
2005-04-24 18:57         ` Simon Wright
2005-04-24 20:05           ` Dmitry A. Kazakov
2005-04-25 22:56             ` Randy Brukardt
2005-04-28 20:26             ` Simon Wright
2005-04-29  8:11               ` Dmitry A. Kazakov
2005-04-29 18:25                 ` tmoran
2005-04-29 19:19                   ` Dmitry A. Kazakov
2005-04-29 20:24                     ` tmoran [this message]
2005-04-30  9:47                       ` Dmitry A. Kazakov
2005-04-29 20:52                 ` Randy Brukardt
2005-04-30 10:02                   ` Dmitry A. Kazakov
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