Re: status of PL/I as a viable language

["John R. Strohm" <strohm@airmail.net>]

"Everett M. Greene" <mojaveg@mojaveg.iwvisp.com> wrote in message
news:20030222.7982838.ABFA@mojaveg.iwvisp.com...
> Hyman Rosen <hyrosen@mail.com> writes:
> > John R. Strohm wrote:
> > > And that "simple little limited regular expression matcher" passed the
> > > formal customer acceptance test on the first try, with no deviations
or
> > > waivers or anything.
> >
> > But it took them *two years* to get it specified, designed, and built.
> > Maybe it was a polished piece of perfection, but that's a very long
> > time to build a message filter.
>
> One has to consider the economics of the situation.  Is perfection
> a requirement or just a target?  There is a point of diminishing
> returns beyond which it isn't worth the time and expense to ensure
> perfection.

In this case, perfection was a requirement.

The message flow modulator is a filter.  Grossly oversimplifying, the data
line carried messages with varying security markings.  Anything carrying
certain marks had to be stopped.

You really don't want a previously-undiscovered bug in your security box to
hand a Top Secret / compartmented message to someone who is not allowed to
receive it.  You REALLY don't want to find out that it has been doing that
for over a year.  In this application, you have to KNOW that there are no
bugs in the software.  You have to PROVE it.  Testing just isn't good enough
to get you there.