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From: gwyn@brl-smoke.ARPA (Doug Gwyn )
Newsgroups: comp.lang.c
Subject: Re: "Cost of Portability" [really deterministic timing]
Message-ID: <5822@brl-smoke.ARPA>
Date: Fri, 1-May-87 15:30:36 EDT
Article-I.D.: brl-smok.5822
Posted: Fri May  1 15:30:36 1987
Date-Received: Sun, 3-May-87 01:34:01 EDT
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Reply-To: gwyn@brl.arpa (Doug Gwyn (VLD/VMB) <gwyn>)
Organization: Ballistic Research Lab (BRL), APG, MD.
Lines: 14

Generally, if one can bound the worst-case response of the system,
and if the maximum possible response time is still sufficient, then
that's good enough.

Also, most reasonable data acquisition systems are buffered, and
if one can guarantee that the buffering is sufficient so that no
overrun will occur, that also is good enough.  This may involve
guaranteed statistical behavior of a non-deterministic system.

Note that an upper bound can be placed on time taken by the code
generated for almost any C expression.  One may have to make
worst-case assumptions, such as a jmp being generated for every
conditional, but most C compilers I've worked on have code
generation tables that can be used to make such predictions.