Re: Boeing and Dreamliner

[aek@vib.usr.pu.ru (Alexander Kopilovitch)]

Hyman Rosen wrote:

>Richard Riehle wrote:
> > The Ada code that caused a problem in Ariane 5 was perfectly
> > good code reused from Ariane 4.
>
>It was not perfectly good code.

It was a good example of politically correct phrase, and you simply failed
to sense all its power and beauty -:). Look again:

"The Ada code that caused a problem in Ariane 5 was perfectly
good code reused from Ariane 4."

This is a correct sentense, it conveys truth, but in such a way that you can't
dissect it or extract contiguous part of it without converting the truth to a
lie. Actually, the SRI software code for Ariane 4 was *perfectly good for
Ariane 4*, although it quite probably was not so good in general -- so your
sentense "It was not perfectly good code." is probably true also.

>While people here are focussed on the fact that the trajectory
>specs were not made part of the specs of the Ariane 5 SRI, the
>actual problem was that the Ariane 4 SRI programmers did not
>indicate that the trajectory specs for the Ariane 4 actually
>impacted the implementation of the SRI code.

The actual problem was the absence of testing (and the report stated it
clearly). The absence or weakness of comments or other indications related
to Ariane 4 SRI software is no more than a contributing factor (surely, it
will be better for those developers to write in red and bold: "This software
is for Ariane 4 only, it relies upon Ariane 4 specifications, it should not
be used for any other purpose!" on the title pages of all their documents).



Alexander Kopilovitch                      aek@vib.usr.pu.ru
Saint-Petersburg
Russia