> > wonders how such an implementation can be validated for compliance with > > annex D. > > Since the semantics are the same whether the same-priority tasks are > running completely in parallel (such as on a multiprocessor) or not, I can > not see any problem that could possibly be a result of time slicing. Could > you send some more information? He didn't say "same-priority." Unless the implementation "does the right thing" the semantics are NOT the same and the implementation should not be validated. If you can not turn off O.S. time slicing, and if the O.S. time slicing does not satisfy the Ada rules, then the Ada RTS must implement all its tasks internally in one process. That way, when the O.S. time-slicing switches to another process, it is turning off ALL of your Ada tasks. Then when it switches back to your program, the task that was running when it switched out is still running. As for a problem from time slicing: I have seen environments where EVERY process is guaranteed CPU time, but the lower priority ones just get less of it. Under the right circumstances, this is allocating resources to a process that has a lower priority. If "process" = "task" then this violates D.1(15).