Re: Space Station S/W in Ada -- No Tasking?

[dewar@merv.cs.nyu.edu (Robert Dewar)]

Bob says

<<Could we possibly be using this approach for a life-critical
system that will run in an incompletely-understood
environment, be subject to extensive and rapid change, and
have a lifetime of decades?
>>

This is of course an old argument, and proponents of synchronous
cyclic scheduling will be glad to produce similar rhetoric denouncing
the use of the asyncrhonous approach.

Of course one has to decide this on a case-by-case basis, but there are
plenty of examples of disasters and successes created using both approaches.

At least some parts o the space station software definitely use cyclic
scheduling (I remember this because I implemented the ncessary CIFO
primitives to support cyclic scheduling for ALsys who was supplying 
Ada compilers for the Space Station effort).