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Date: 17 Oct 92 01:29:52 GMT
From: cis.ohio-state.edu!udecc.engr.udayton.edu!blackbird.afit.af.mil!mawhelan@
ucbvax.Berkeley.EDU  (Michael A. Whelan)
Subject: Re: What is "real-time"?
Message-ID: <1992Oct17.012952.13340@afit.af.mil>
List-Id: <comp.lang.ada>

Real-time software does not have to be fully deterministic.  It has to
meet the deadlines of the application domain for a response.  The key is
deadline or response time guarantee.  As long as an acceptable response
is made by the deadline, then it operates in real-time.  If by
deterministic you mean ability to meet deadlines than I agree. 
If however you mean the response is exactly the same, i.e. can be
determined for every case than I must disagree.  Since we are found of
using missiles and pilots, imagine what a pilot would think of a missile
avoidance system that responded deterministically.  The first it might
work great, the second time it might be okay.  The third time the
aircraft does not return.  The reason is the responses were
deterministic.  Even to the guy shooting.  Again, the key is meeting a
response time requirement for the application domain, not a fully
deterministic system.  


P.S.  My wife operates in real-time, but I truly believe she is not
deterministic!

Mike Whelan