Re: Reactive Systems in Ada?

[Matteo Bordin <matteo.bordin@gmail.com>]

On Apr 7, 10:25 am, Dimonax <dimo...@nospam.net> wrote:
> I've been experimenting with the Ravenscar profile and the various
> tasking facilities available in Ada.
>
> I'm curious, has anyone written any Reactive Systems of any sort using
> the Concurrency features in Ada?
>
> How does it compare to Reactive Languages such as Esterel, or Lustre,
> etc...?

Both Esterel and Lustre are domain-specific, formal modeling
technologies and thus have a completely different scope/goal than a
general-purpose programming language such as Ada. From a computational
model point-of-view, they employ the synchronous execution model and,
if they target source code, they generate purely sequential code (no
threading). Ada on the other side employs the asynchronous/parallel
model. The main advantage of asynchronous model is that it can easily
scale to multi-core (or multi-processors) systems and is easier to
compile. However, synchronous systems are usually much simpler to
analyse for their timing behaviour, information/data flow and to prove
properties on the system state.

It is possible to imagine a concurrent system whose concurrency/
synchronization architecture is implemented in Ada (possibly using
Ravenscar) and executing in (pseudo)parallelism a set of SCADE blocks.
Take a look at "A verifiable architecture for multi-task, multi-rate
synchronous software" (http://www.esterel-technologies.com/technology/
WhitePapers/).


>
> My curiosity is piqued.
>
> Dimonax