Re: Ada as a real time language

["Pat Rogers" <progers@classwide.com>]

"Mikael Lundqvist" <mikael.lundqvist@avionics.saab.se> wrote in
message news:3D6CEB7E.E6930EAD@avionics.saab.se...
> I have heard that the Ada Run Time doesn't handle load
> that well. If you have to many tasks or to much input/output
> the Runtime gives in so to speak. In that regard you should
> be better of with a RTOS. I have not any experience myself
> with large Ada programs. Anybody out there who could comment?

To be precise, there is no such thing as *The* Ada Run-Time; perhaps
you heard about some vendor's buggy *implementation*?  There is no
reason to expect an implementation to fail (is that what you mean by
"give in"?) because there are many tasks or a lot of I/O.  Failure in
such a case would be a bug.

Certainly the performance will vary with the load, just as it would
with an (RT)OS present.  If the performance degrades more quickly than
necessary, that is either a poor implementation or one that is making
tradeoffs in other areas that are not appropriate for the specific
application. Who knows.

For that matter, when Ada is used with an RTOS it is reasonable (and
probably typical) to expect that an Ada task is mapped directly to an
RTOS thread -- on other words, an Ada task *is* an RTOS thread -- so
there would be no difference.  That is the case with GNAT on VxWorks,
to cite one example vendor and RTOS.

We'd be better sticking to facts than what one has heard.