Re: [Fwd: F22 completes 11% of its Flight tests]

[kdevlin@mpinet.net (K. Devlin)]

On Sat, 15 Jan 2000 02:04:58 -0000, "Keith Willshaw"
<keith_willshaw@compuserve.com> wrote:

>
>Bill Greene wrote in message <387FCA73.3A61@Ganymede.com>...
>>Ed Falis wrote:
>>
>>Perhaps he is really complaining about the instruction set of a CPU or
>>processor architecture (the VAX), and not about a programming language
>>(Ada) at all.  Note his assertion that "VAX" violated some alleged
>>design goal of Ada.  Having tried unsuccessfully to discover his meaning
>>by direct questions, all I can conclude is that he is blaming the Ada
>>programming language (which he apparently thought was designed by DEC)
>>for the fact that the VAX is non-compliant with the Data General
>>instruction set!
>>
>
>
>More liley its DEC's own compiler he's complaing
>about. Their Fortran compilers had lots of extensions
>that were far from ANSI standard Fortran.
>
>My company had to move a lot of this stuff from
>VMS to Unix and then NT
>
>The DEC extensions were a major headache
>
>Keith
>
>
Have to agree, DEC FORTAN has lots of non-standard extensions, in the
DEC FORTRAN manual I have these extensions are printed in blue to make
them easy to identify. If you stayed away from them, then the program
"should" be portable to any other "standard" FORTRAN.

Ada is much better in this regard. One of the nice features of Ada it
makes it easier (and as far as the compiler itself, requires it) to
compartmentalize the system specific "stuff". If done right (and I
realize thats a big IF) changing processors should be easier using Ada
than any other language. 

As far as processors themselves:

An option I havn't seen mentioned is the life-time buy option.  It has
been done in the past and could have been done for the F-22's i960
(but I don't know if it has) where the quantity of processors (or any
other part) determined to be needed to build some number of systems
and maintain same for a specified period of time, are bought before
the vendor stops production and are put into storage.

However I see that money is being spent to develop an upgrade for the
F18E/F (Military&AeroSpace Electronics Jan 2000 Vol 11 No 1) with a
PowerPC based board from DY 4. While the DY 4 board doesn't currently
appear to be one of the targets for an Ada compiler, rehosting isn't
THAT hard if you start with a compiler that meets the standard for the
processor.  (I count 7 different vendors of PowerPC based compilers
http://www.adaic.org/cgi-bin/vcl/report95.pl) 

For additional information on Ada:

The following URL is an online copy of the Ada reference Manual:

http://www.adapower.com/rm95/index.html

Section 1.1.3 Conformity of an Implementation with the Standard
discusses what's required to conform to the standard
(http://www.adapower.com/rm95/arm95_16.html#SEC16).

kbd