Re: SBIRS, Ada and Ignorance
Some answers about the SBIRS program.
- The SBIRS program was plagued by poor initial systems engineering.
Those responsible have been replaced and we were able to get the
program somewhat back on track last fall. We can't undo all of the
stupid mistakes but I think we can get at least 95% functionality.
(The more optimistic think we can score 100%)
- Flight software is written in Ada 95 using Rational Apex compiler.
The only problems we've had with the development environment were
self-induced (e.g., attempting an Apex/ClearCase integration before
it was released by Rational).
- We considered GNAT at the start of the project and contacted ACT.
For whatever reason, they weren't interested in developing a GNAT
compiler for us. (I don't think they realized that we would play
for the development.) In any case, we're happy with Rational Apex.
- We also considered using a GNU C/C++ compiler but it ran slower
than the Rational Ada code. This isn't an Ada is faster than C++
claim -- Lockheed-Martin spent a lot of money to have a good Ada
compiler available; the C++ compiler was an afterthought for the
hardware test group.
- There were several subtle hardware glitches that required software
fixes. This is a typical problem for a development program.
We all learned Chapter 13 of the LRM by heart.
Anyone claiming that Ada was the problem is either ignorant of the
circumstances or hoping to obscure the initial systems engineering
problems. In fact, Ada's language features allowed us to get as
far as we have.
Joe Vlietstra
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