Re: Open Systems closed to Ada?

[agate!usenet.ins.cwru.edu!magnus.acs.ohio-state.edu!zaphod.mps.ohio-state .edu!cis.ohio-state.edu!news.sei.cmu.edu!ae@ucbvax.Berkeley.EDU (Arthur Evans)]

mfeldman@seas.gwu.edu (Michael Feldman) says:
>> My experience is that the projects are sufficiently complex that the
>> numbers can be cooked to show savings or lack of savings according to
>> the motive of the writer. Lots of people are trying to show that Ada
>> saves money, and because they want these numbers to come out right,
>> they do. Others want just as desperately to show no savings, and I'm
>> sure the numbers would come out their way too. Maybe I'm too cynical,
>> but I don't put all that much faith in these arguments, one way or
>> the other.

True, of course.  Nonetheless, the paper "Ada Outperforms Assembly: A
Case Study" (citation below) given at TRI-Ada '92 last month is surely
relevant.  I quote the abstract in its entirety:

    With the intent of getting an Ada waiver, a defense contractor wrote
    a portion of its software in Ada to prove that Ada could not produce
    real-time code.  The expectation was that the resultant machine code
    would be too large and too slow to be effective for a communications
    application.  However, the opposite was verified.  With only minor
    source code variations, one version of the compiled Ada code was
    much smaller while executing at the same speed, and a second version
    was approximately the same speed but much faster than the
    corresponding assembly code.

What was interesting here is that they intended to prove Ada inadequate
and ended up proving just the opposite, somewhat to their initial
dismay.  Details are in the paper, which I commend to your attention.

Here are two quotes from the paper, both being paragraphs quoted in
their entirety:

    How can a compiler for a high-order language beat assembly code in
    both size and performance?  It is because of a reasonably high level
    of maturity on the part of compiler development in general and the
    compiler vendor in specific.  When a vendor brings a wealth of
    experience to bear on optimization, it goes beyond the capabilities
    of any one individual, no matter how experienced.

    QRS [the pseudonym for the defense contractor, which is not
    identified] is convinced.  It has now decided to use Ada extensively
    because it believes the use of Ada will provide the company with a
    competitive edge in the market place.

The paper is by Patricia K Lawlis and Terance W Elem and appears on
pages 334-337 of the Conference Proceedings.  I suspect that you can get
a reprint from Tartan, which is rather proud of the fact that their
compiler was used.

Art Evans
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Arthur Evans, Jr, PhD           Ada Consultant
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