Re: Ariane 5 failure

["Marin David Condic, 407.796.8997, M/S 731-93" <condicma@PWFL.COM>]

Matthew Heaney <mheaney@NI.NET> writes:
>
>Why, yes.  If the rocket blows up, at the cost of millions of dollars, then
>I'm not clear what the value of "faster execution" is.  The rocket's gone,
>so what difference does it make how fast the code executed?  If you left
>the range checks in, your code would be *marginally* slower, but you'd
>still have your rocket, now wouldn't you?
>
    It's not a case of saving a few CPU cycles so you can run Space
    Invaders in the background. Quite often (and in particular in
    *space* systems which are limited to rather antiquated
    processors) the decision is to a) remove the runtime checks from
    the compiled image and run with the possible risk of undetected
    constraint errors, etc. or b) give up and go home because there's
    no way you are going to squeeze the necessary logic into the box
    you've got with all the checks turned on.

    It's not as if we take these decisions lightly and are just being
    stingy with CPU cycles so we can save them up for our old age. We
    remove the checks typically because there's no other choice.

    MDC

Marin David Condic, Senior Computer Engineer    ATT:        561.796.8997
M/S 731-96                                      Technet:    796.8997
Pratt & Whitney, GESP                           Fax:        561.796.4669
P.O. Box 109600                                 Internet:   CONDICMA@PWFL.COM
West Palm Beach, FL 33410-9600                  Internet:   CONDIC@FLINET.COM
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