Re: is Ada used in James Webb Space Telescope software?

[Niklas Holsti <niklas.holsti@tidorum.invalid>]

On 2021-12-27 2:37, Paul Rubin wrote:
> John McCabe <john@mccabe.org.uk> writes:
>> I didn't realise there had been so many projects in Forth.
> 
> Much of Forth's early development was at the Kitt Peak observatory where
> I think Charles Moore worked for a while, so it was popular with the
> astronomy community and maybe indirectly with the spaceflight community
> through there and JPL.  As a more general matter, hardware designers
> (electrical engineers who sometimes have to muck with embedded software
> but aren't really into programming as a topic) tend to like it because
> of its simplicity and directness.


Forth is of course one of the few ways to get a self-hosted but fairly 
fast interactive compiler/editor system on small processors.

In the 1980's I was working in radio astronomy and we were planning to 
use Forth to replace HP BASIC on an HP2100 16-bit mini for telescope 
control and data acquisition. I had a little crush on Forth at the time, 
but fell out of love with it when I found that some astronomy SW had 
defined the word 2000.0 as a procedure to convert stellar coordinates to 
the year 2000 ephemeris... very clear :-(

Fortunately IMO we chose to use HP-Algol instead, and much later changed 
to Ada on a MicroVAX.


>> as it looked like we (Matra Marconi Space) might be forced to use the
>> RTX2010 as it was one of very few space qualified processors with
>> hardware floating point support. In the end we used the MA31750, with
>> Ada, instead.
> 
> Interesting.  I hadn't heard of the MA31750 but it appears to be a 16
> bit processor that implements the MIL-STD-1750A instruction set(!),
> which I didn't know about either.  Apparently it was made in the 1980s
> but has since been superseded by SPARC architecture cpu's.
> 
> I wonder if targeting GCC to the RTX2010 might have been feasible.
> Can I ask what Ada compiler you used for the MA31750?  It looks like GCC
> supported the MA31750 until version 3.1, but I don't know whether GNAT
> existed then.


Like John, I used Ada on an MA31750. We used the TLD Ada compiler, where 
(IIRC) TLD stands for the main author, Terry L. Dunbar. GNAT was around, 
but I don't remember if it had support for the MA31750 -- I doubt it. We 
used gnatp 3.<something> for testing the MA31750 SW on workstations (Sun 
Solaris on SPARC, IIRC), but the customer (Matra Marconi Space) 
specified TLD Ada for the target, so there was never a question of using 
GNAT instead.

That project developed the on-board SW for the ozone-monitoring 
instrument GOMOS on the ESA ENVISAT satellite. I believe ENVISAT used 
MA31750 and TLD Ada for all its systems.