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From: Alan Brain <aebrain@dynamite.com.au>
Subject: Re: ada and robots
Date: 1997/06/10
Message-ID: <339E143A.349D@dynamite.com.au>#1/1
X-Deja-AN: 247407272
References: <97060510114032@psavax.pwfl.com>
 <339C1ECF.431B@mlb.cca.rockwell.com>
Organization: @Home
Reply-To: aebrain@dynamite.com.au
Newsgroups: comp.lang.ada
Date: 1997-06-10T00:00:00+00:00
List-Id: <comp.lang.ada>


> > Joe Gwinn <gwinn@RES.RAY.COM> writes:
> > >In practice, C was much more successful than Ada83 at riding metal.
> > >Experience with Ada83 shows that it is very bad at direct control of
> > >hardware, especially I/O hardware, and simply does not handle shared
> > >memory correctly.

> Marin David Condic, 561.796.8997, M/S 731-93 wrote:
> >     Maybe with some of the early generation compilers, but we've been
> >     "riding the metal" for years here in Ada and never had any trouble
> >     getting direct control over the hardware.

Jerry Petrey wrote:
> I agree.  As I discussed in an "Embedded Systems Programming" article in
> Sept 95, I did all the low level hardware checkout and built-in test
> software for a gas turbine engine controller in Ada83 using the Rational
> VADScross compiler and found it to be quite easy at getting to "the
> metal".

If Ada-83 is, quote "very bad at direct control of hardware, especially
I/O hardware, and simply does not handle shared memory correctly."
that's news to STN-Atlas Elektronik GmbH.
Submarines in at least 6 navies rely on Ada-83 code that handles shared
memory as the I/O on a VME bus in the CSU-90 and ISUS-90 projects. In
addition, Ada-83 was used extensively for the I/O handling on the BM-502
MFCC consoles on the F-123 class Frigates.
Finally, Ada-83 was used by STN-Atlas on the SEC project, where its
facilities were used by Oerlikon-Contraves Zurich to debug their
software (written in C). The Ada code was so reliable, robust and able
to diagnose problems with incoming telegrams without a debugger and in
real-time. Whereas the C code and that specific deveopment environment
couldn't.

Maybe some early compilers had problems. But not ones built after about
1990.

BTW I was the Team leader for the VME databus comms, and made the
decision to re-write old C code in Ada-83 at the lowest level. Found
bugs in code that had been 'working' with occasional unexplained
glitches for 5 or more years.

-- 
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