Re: Interesting thread in comp.lang.eiffel

["Ken Garlington" <Ken.Garlington@computer.org>]

"Veli-Pekka Nousiainen" <vp.nousiainen@lapinlahden-teknologiakeskus.fi>
wrote in message news:vnZc5.210$2y3.8676@read2.inet.fi...
> What if I'm _designing_ a new control computer (Endaira v.4 -> v.5)
> and a new software for it. Maybe I want the contracts from
> the earlier HW/SW builders and some test material?

Certainly. Sextant had both, and used both (since they *were* the original
builders).

> Here we go again: You think I would have used that old
> test material right away, don't you?

No, you probably would have compared it against your revised requirements.
And, as in the Ariane 5 case, if your requirements had a hole in them (but
were internally consistent), you probably would have ended up with a poor
validation test (as did Ariane 5). Then, if your software was never tested
by someone who had the information that would have filled that hole, they
obviously wouldn't have caught the problem (as in the case of Ariane 5).
Then, if your software were put in the system where the hole WAS filled
(because it's the real system!), and the system executed, it quite possibly
would find the hole (as did Ariane 5 -- with catastrophic results)!

As a simple example -- determine if the implementation below meets the
requirement:

-- Requirement: Set the variable to the value 100

X := 100;