Re: ARIANE-5 Failure (DC-X works)

[Ken Garlington <garlingtonke@lmtas.lmco.com>]

Robert Dewar wrote:
> 
> The people writing this [MatrixX] *are* programmers, they are programming. There is
> no difference between a program and an executable specification. In fact
> that's all a program is -- a specification of what needs to be done with
> a method for automatic translation into a machine that does the task.

I can't find fault with the technical accuracy of your statement. However, when I
say "the people who use MatrixX usually aren't programmers," I mean that they
are not always acquainted with knowledge which most people would expect
software engineers to know. For example, although MatrixX permits the decomposition
of diagrams into modules, the average MatrixX user would probably not think too
much about the long-term maintenance effects of their choice of module interfaces.
Also, they usually don't consider the effects of algorithm choices on throughput
or memory. Therefore, they may not be fully equipped to make decisions about the
best language to use when generating code. This decision might -- and I emphasize
might -- make a difference in the quality of the final product, however.

> The
> policy of using Ada applies to the INPUT, not the OUTPUT of the programming
> effort, so in this particular case, if the Ada policy applies, a waiver is
> needed to program part of the aplication in MatrixX instead of in Ada.

Actually, I'm not sure I agree with this. If I deliver the output to the depot,
I don't know if I need a waiver or not. When I've asked this question in the
past, I've always been told that a waiver is not required. Could you cite
where you think the policy excludes the output from consideration? This is
pretty important, since some F-22 Ada code is auto-generated, and by your
definition I would need a waiver for all these cases!

> The use of very high level languages is a very important advance in
> proramming technology, one that has been very slow in coming, but the
> notion that somehow this eliminates the need for programming of
> programmers is absurd and likely to lead to bad decisions.

I certainly agree with this! However, if the 4GL decomposes into Ada code,
and that Ada code is delivered, I think right now the policy assumes that
no waiver is required. (Note that the policy also allows Ada to be written
by people who have no business writing programs!)

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