Re: naval systems

["John R. Strohm" <strohm@airmail.net>]

"Marin David Condic" <dont.bother.mcondic.auntie.spam@[acm.org> wrote in
message news:a55m56$6mk$1@nh.pace.co.uk...
> "David Gillon" <david.gillon@baesystems.com> wrote in message
> news:3C763746.CC8B2965@baesystems.com...
> >
> >
> > Andrew Swallow wrote:
> > >  The runtime support code
> > > needed more memory than most embedded computers had.
> >
> > Only if you didn't tailor it. And how has the embedded market reacted to
> > this supposed limitation? Gone all out for run-time operating
> > systems.....
> >
> Good point. I've built embedded systems with Ada that had nice, small RTKs
> that could be cut down to just what you needed and no more. For very tiny
> computers, you probably couldn't get the whole of Ada into them, but if
you
> made intelligent choices about what you needed, you could get all the way
> down to *NO* RTK if necessary.

Something over ten years ago, I took an Ada training class at Texas
Instruments.  (It was really a review for me, but I needed the review.)  One
of the features of the class was a videotape of a Q&A session with Jean
Ichbiah and two other Ada luminaries.

Ichbiah was asked that precise question, about the size of the runtime, and
how it seemed that it would be too big for anything practical.

His answer was that a just-about-fully-compliant Ada runtime module had been
written in 4K words.  Note well his choice of words:  not "could be" but
"HAD BEEN" (emphasis added).

Not long after that, I had occasion to check that answer, for the Tartan
Labs toolset for the TI 320C30 32-bit floating point digital signal
processor.  The Ada runtime module for that processor was, indeed, about 4K
words.  This rather shocked my supervisor at the time; he'd just assumed it
would be prohibitively big and NEVER LOOKED.

I don't know very many embedded systems that can't scratch up 4K words of
code space for a runtime kernel.