Re:Language Used in Spacecraft Computers

Thomas Anderson wrote:

> oh, Ada. run! run! a language cooked up by the DoD 

This statement is a little "factually challenged". Would you care to
read the history of the language, and try again? Try having a look at
http://www.adahome.com/

> ada was used in the on-board computer on Ariane 501. Ariane 501 was
> lost in flight because the on-board computer was unable to correctly
> handle a sensor misconfiguration.

Nope. At least, not quite. They re-used software from Ariane IV whose
specifications said, basically, "If you accelerate faster than X, it
means the ship's blown up, so dump everything you can on telemetry even
though this will break everything else."

The software worked exactly to specification, directly causing loss of
the ship shortly after launch, as the specs said it should. DOH!

Ariane V had a lot more accelleration than Ariane IV... and management
refused to check the specs were still valid. This just proves that
management stupidity baffles even good software engineering.

> those who are into programmatic self-discipline could also look at
Eiffel,
> for which there are also free compilers (www.eiffel.com).

An excellent language too! Design-by contract is a useful feature. Wish
it had more of em.

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