Re: Would You Fly an Airplane with a Linux-Based Control System?

[Simon Wright <simon@pushface.org>]

Marius Amado Alves <amado.alves@netcabo.pt> writes:

> Sentences like "the behavior of the Ada SW was exactly that
> specified for this situation" (above) or "The software behaved
> _exactly_ as specified" (Vinzent) are worse than irrelevant, they
> are confusing, and actually strictly false. Surely the specification
> for Ariane 5 did not say "plug in software from Ariane 4 at will and
> crash on hardware mismatches."

This argument is just piffle in any reasonably-managed engineering
environment.

Of course the SYSTEM specification said no such thing, how could
it. But the SOFTWARE specification, produced by the SYSTEM engineers
(or maybe management) told the software engineers to do that and not
to check the results -- as software engineers they couldn't have
anyway, you need rigs for that sort of test.

It is perfectly possible for a SYSTEM to have bugs as a result of
containing bug-free but inappropriately specified software.

You would hardly describe software that required an FPU as "buggy" if
it failed to work on a processor without one.

-- 
Simon Wright                               100% Ada, no bugs.