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Date: 16 Oct 92 13:11:57 GMT
From: cis.ohio-state.edu!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!rela
y!apssgi.nswc.navy.mil!bwallet@ucbvax.Berkeley.EDU  (Brad Wallet)
Subject: Re: Ada and real-time
Message-ID: <1992Oct16.131157.27995@relay.nswc.navy.mil>
List-Id: <comp.lang.ada>

In article <1992Oct15.163026.7899@saifr00.cfsat.honeywell.com>, walls@saifr00.c
fsat.honeywell.com (Gerald Walls) writes:
|> In article <1992Oct15.144135.24045@sei.cmu.edu> jbg@sei.cmu.edu (John Gooden
ough) writes:
|> >
|> >By "non-deterministic tasking" do you mean the fact that it can be difficul
t
|> >or impossible to write down a timeline for a set of Ada tasks, given
|> >variations in execution times and the effect of preemption?  If so, this is
|> >not, in itself, sufficient reason to conclude that Ada tasking is unsuitabl
e
|> >for embedded real-time systems.  
|> >
|> 
|> the FAA requires this in avionics software.  Ada tasking is not
|> suitable for real-time avionics software.

But, the FAA is requiring the use of Ada.  Ada tasking is deterministic
given a set of circumstances.  The external inputs to the Ada program are
not deterministic.  Ada running under Unix will not be deterministic.  This
is because of the external effects of the operating system, but, then 
again, Unix is not a suitable real-time operating system.

Brad