Re: Array mappings

[dewar@cs.nyu.edu (Robert Dewar)]

Mike, I know you enjoy vendor bashing, but let's keep facts straignt (and
this particular point is one I have made before). You DEFINITELY cannot
say that Alsys was "fixated" on the DoD market when it was first formed.
For years, it agressively persued the non-DoD market, and please note that
there is not very much US DoD business in France, where Alsys had some
considerable success in penetrating various application fields.

Indeed, Jean always thought of Ada as a general purpose language with
possible application to a wide variety of fields. Some people even
criticized Jean for not being sufficiently concentrated on the US DoD
market!

As for your question of what is more important than the array ordering
matter, I would say two things:

   Realiability and maturity (note the posting we already saw on this issue)

   Performance. This is a really tough one, Fortran compilers typically have
   been squeezed furiously on performance of numerical loops, and are where
   you find the most aggressive optimization of this type of code. The
   effort of competing in code quality with mature optimizing Fortran
   compilers was and is huge and very expensive.

You keep saying that what you want to be sure is that vendors did extensive
market surveys of this part of the market. I don't know how much business
experience you have, but this is the sort of thing that is often recommended
by people without such experience. THe fact of the matter is that meaningful
surveys of markets are VERY difficult and VERY expensive. The trick in a
market like the Ada market is to be able to guess where to go WITHOUT blowing
huge amounts of capital in studies like this that do not turn out to be
useful.

My own feeling is that the performance issue was so central at the time,
that there was little chance for Ada to make serious headway (one of the
problems with the Cray compiler was that, espeically early on, it was a
little bit less efficient than Fortran).

As to why numerical people are moving to C, it is partly because they are
moving to work stations where C is perceived as part of the general
environment, and yes, I do think this represents an opportunity!