Re: Ariane5 FAQ, Observer's version, 8th draft

["Alexander E. Kopilovich" <aek@VB1162.spb.edu>]

Brian May wrote:

> I would argue this was in fact an error in the software installed,
> even though the software itself did exactly as in intended.
>
> If I accidently installed software designed for my Microwave oven in
> my fridge, and my fridge subsequently tried to cook food rather then
> cool/freeze food, I would still consider it an error in the software
> installed. Despite the fact the software did exactly as intended.
There may be an error to blame either in the software installed or in the
software of that your fridge, because that improper coupling of components
at general consumer level was not prevented.

If you get an installable software bundle for microwave oven as a general
consumer (bought CD with it or downloaded it from vendor's website), you may
expect that reasonable precautions will be taken against improper use of it;
both sides - your fridge (which permits installation of separately obtained
software and then takes instructions from it) and the software bundle are
responsible for those checks.

If those checks were designed, but did not prevent inappropriate coupling
because of their improper implementation at the software level - then there
was a software error to blame indeed. Otherwise (for example, the checks were
not designed at all) the construction of your fridge is seriously flawed.

I think that your example is perfectly in line with the explanation, which is
given in the next (4th) Q-A pair of the FAQ (and is based on the effects of
general consumer's expectations).





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