Re: Ada to C Translator

["Ken Garlington" <Ken.Garlington@computer.org>]

Your mentioning the F119 raises a question in my mind that I probably should
have asked a long time ago. IIRC, the Pratt & Whitney gang used Pictures to
Code extensively for the engine control. Did the advantages you describe
below (easy to read, etc.) really matter in that case, given that Ada
essentially became an intermediate language? Now that the rest of the world
seems to be catching on to this idea (automatic code generation from UML,
etc.), I wonder if that trend is going to make other attributes of
text-based languages more important - portability, availability and
robustness of associated compilers, etc. No one extols the readability of
J-code, do they?


"Marin David Condic" <mcondic.nospam@acm.org> wrote in message
news:3A531C4D.7AB64631@acm.org...
: Speaking as someone who has worked on projects with a similarly long or
: longer lifecycle, I'll throw this in: Nobody has a crystal ball with
enough
: magnifying power to see that far ahead. Example: The F119 engine for the
: Advanced Tactical Fighter was in various stages of development for over
ten
: years before it went into production. In that ten years, the engine
control
: went from running 68000 processors to 68040 processors (with stops in
: between). Before it got to production, Motorola decided that they weren't
: going to make a Mil packaged version of the chip anymore no matter how
much
: whining and snivveling we did. The box will ultimately go into production
: using PowerPC chips. The project had frozen a version of the XD-Ada
compiler
: for a long time and kept VAX/VMS systems around to run it on in spite of
: everyone else at the company going to Sun/Unix platforms. Eventually the
: project was forced to move on to the Aonix Ada95 compiler for the PowerPC
: chip. All that meant major rewriting of the system level software and
: reverification of the control. No small task.
:
: Since projects like this can't possibly forsee what will happen 20 years
: from now (new charged particle phased plasma fluidic computational
devices?
: or maybe total economic colapse followed by a meteor impact that throws us
: all back to the stone age?) the powers that be on the project have to have
a
: plan to deal with the inevitable changes. If you were to, for example,
pick
: Ada as your programming language and Linux as your OS, what you would want
: to do is design the software to isolate machine/OS specific features so
they
: could easily be replaced and develop your software so that it is clear,
: easily understood and readily translated if that need should arise. Ada
: shines in these areas for lots of reasons such as readily understood
syntax,
: modular construction, etc. Ada was designed specifically to support large
: projects with a long lifespan. If you write it in Ada, at least your
: grandson can come along 20..30 years from now and maybe understand what
you
: did and translate it into C** or F# or whatever is the new, hip computer
: language  at that time. (Personally, I'm predicting a resurgence in the
use
: of Jovial. :-)
:
: What was it they said in The Mythical Man-Month? When you develop
software,
: plan to write it twice because you will anyway.
:
: MDC
:
: Dave Ptacek wrote:
:
: > I would be interested in some suggestions as to what languages and
: > toolsets would be viable alternatives for maintaining a program 15 - 20
: > years into the future.  Please try to take the Ada hat off before you
: > respond, it still might be your choice, attempt to rationalize it with
: > reasonable statements, consider the logistical situation noted above and
: > lastly this is not a "deep pocket" program so funds are limited.
:
: --
: ======================================================================
: Marin David Condic - Quadrus Corporation - http://www.quadruscorp.com/
: Send Replies To: m c o n d i c @ q u a d r u s c o r p . c o m
: Visit my web site at:  http://www.mcondic.com/
:
:     "Giving money and power to Government is like giving whiskey
:     and car keys to teenage boys."
:
:         --   P. J. O'Rourke
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