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From: rmj@tcom.stc.co.uk (Rhodri James, the beardless wonder)
Newsgroups: comp.lang.c
Subject: Re: Crash a RISC machine from user-mode code:
Keywords: Stress
Message-ID: <1860@islay.tcom.stc.co.uk>
Date: 17 Aug 90 13:35:09 GMT
References: <1990Aug13.053147.11714@laguna.ccsf.caltech.edu> <481@demott.COM> <1990Aug15.052856.28006@laguna.ccsf.caltech.edu> <17425@haddock.ima.isc.com> <1990Aug16.051437.21661@laguna.ccsf.caltech.edu>
Reply-To: rmj@htc1.UUCP (Rhodri James, the beardless wonder)
Organization: STC Telecomms, Harlow Technical Centre, Harlow
Lines: 37

In article <1990Aug16.051437.21661@laguna.ccsf.caltech.edu> bruce@seismo.gps.caltech.edu (Bruce Worden) writes:
>In article <17425@haddock.ima.isc.com> karl@kelp.ima.isc.com (Karl Heuer) writes:
>>In article <1990Aug15.052856.28006@laguna.ccsf.caltech.edu> bruce@seismo.gps.caltech.edu (Bruce Worden) writes:
>>>In article <481@demott.COM> kdq@demott.COM (Kevin D. Quitt) writes:
>
>>>>....  But when you try to stress the system, it's going to fail.
>
>>>[Disagree.]
>
>>Clarify.  Are you saying that (a) the `crashme' program never causes your
>>machine to crash, (b) such a crash does not constitute `failure',[...]
>
> [...]    (b) that such a crash does not constitute `failure' unless it 
>significantly detracts from the machine's utility.  By `significant' I 
>mean more than a few percent of a given installation's system crashes 
>are caused by the bug.

Here I have to side with Karl. Given that the crash can happen with a
program following a rogue function pointer off into the wide blue
yonder, something which is not implausible in a development environment,
then just ignoring it is very short sighted. However you look at it,
your system is then shown to be vulnerable to crashing, deliberate or
accidental. You might consider the degree of risk acceptable in your
conditions, I certainly wouldn't accept it in an academic or commercial
development environment.

Again; you may consider the risk acceptable, just don't ask me to. I'll
see you after the next crash.

The problem is basically that your definition of "failure" is much less
stringent than mine or Karl's, or a fair number of other contributors to
this argument at a guess.
-- 
* Windsinger                 * "Nothing is forgotten..."
* rmj@islay.tcom.stc.co.uk   *                    Mike Whitaker
*     or (occasionally)      * "...except sometimes the words"
* rmj10@phx.cam.ac.uk        *                    Phil Allcock