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From: Niklas Holsti <niklas.holsti@tidorum.invalid>
Newsgroups: comp.lang.ada
Subject: Re: How large were MIL STD 1750A Ada-running systems?
Date: Thu, 11 Oct 2012 23:03:57 +0300
Organization: Tidorum Ltd
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Date: 2012-10-11T23:03:57+03:00
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On 12-10-11 20:57 , mjsilva@scriptoriumdesigns.com wrote:
> I wondered about this in another thread, but thought I'd start a
> separate thread for visibility.  How large (how much memory) were
> 1750A systems that ran ran Ada (and especially, Ada with some form of
> tasking)?

I worked on one 1750A application, at Space Systems Finland Ltd: the
on-board Application SW for the GOMOS ozone-monitoring instrument on the
ESA ENVISAT satellite (which was a mostly-or-completely Ada satellite,
as I remember).

I think this system had the full 64 kilo-words (128 KiB) of code memory
but only 32 kilo-words (64 KiB) of data memory. We used the TLD Ada
compiler, but (by the customer's decision) a small RT kernel instead of
Ada tasking.

As I remember, some other 1750A systems on ENVISAT needed more memory,
and had to use banking schemes to extend the 16-bit address space (with
the predictable problems that causes).

> I'm only asking about 1750A systems because it was a fairly small
> device with, from what I read, a lot of Ada activity.  What I'm
> really curious to know is how much memory should be required on a
> modern 32-bit device to run a small Ada application with e.g.
> Ravenscar tasking, but without the entire runtime support that full
> Ada requires.

Sorry, I have no experience of Ada tasking on the 1750A. But it seems to
me that the RTOS we used was about as complex as Ravenscar tasking, and
it was definitely not the major consumer of code memory.

-- 
Niklas Holsti
Tidorum Ltd
niklas holsti tidorum fi
      .      @       .