When do Ada compilers make scheduling decisions...

[dog.ee.lbl.gov!hellgate.utah.edu!caen!uakari.primate.wisc.edu!samsung!umi ch!umeecs!dip.eecs.umich.edu!warack@ucbvax.Berkeley.EDU (Christopher Warack)]

General question...  When do Ada compilers make scheduling decisions?
Or, when are context switches possible.  For sake of discussion, consider a
single processor with multiple tasks.

The LRM discusses blocking a task during rendezvous's and completion of
task activation before beginning the first statement following the
declarative block or statement following task creation.  What other
conditions are there?  Are time slice schedulers used?

When priorities are used, the LRM requires a higher priority task to run
when both it and a lower priority task are waiting to execute.  What if a
higher priority task becomes "available" while the lower priority task is
running (e.g., expiration of a delay statement).

What prevents a non-blocking (no-rendezvous, no shared vars, no I/O) task
from running forever.  (I suppose this may be pathological, since this
implies that the task does not communicate so cannot do anything useful.)
Related, will a task that encounters a "non-termination" bug "hang" the
whole system?

How are shared variables handled?

I realize that this may be compiler dependant.  I'm interested in how
various implementations differ, however.

-- Chris
--
Christopher A. Warack                   warack@eecs.umich.edu
Graduate Dept, EECS			(313) 665-4789
University of Michigan


-- 
Christopher A. Warack                   warack@eecs.umich.edu
Graduate Dept, EECS			(313) 665-4789
University of Michigan