[Haskell-cafe] Stone age programming for space age hardware?
michael at schuerig.de
Sun Jun 6 13:05:27 EDT 2010
A few days ago, I watched a presentation by Gerard Holzmann on the
development methodology and programming techniques used at JPL for
writing the software for the next Mars mission. I found the talk
entertaining and learned a few things.
Among the arsenal of methods they use to ensure correctness is model
checking for the algorithms used as well as rather restrictive coding
standards. Well, model checking sounds good, real formal oomph. But the
coding itself? For one thing, they're using C. On top of that, the
coding standards prohibit dynamic memory allocation, recursion, and
loops without explicit bounds; see [*] for more details.
I was dumbfounded, although I have known all this. I have no personal
experience with either embedded or real time software, but I've been
aware that C still is the most popular language for that purpose and
that coding standards are very restrictive.
The real reason behind my surprise was, that I was wondering how more
modern languages could make inroads into such an environment. Haskell
without recursion and dynamic memory allocation? Hard to imagine.
I have a hunch that the real restrictions of this kind of software are
not concerned with fixed memory, iterations, whatever, but rather with
guaranteed bounds. If that is indeed the case, how feasible would it be
to prove relevant properties for systems programmed in Haskell?