[comp.realtime] real-time scheduling

dbae@beach.cis.ufl.edu (Doohwan Bae) (04/12/90)

Hello!
I am a student working on real-time scheduling.
I have read a paper recently regarding ``cyclic executive'' used to schedule
real-time tasks.  The paper tell that cyclic executive can be used to 
schedule tasks that have precedence relations, but I do not know of it.

So, my question is:
	Q: Is it possible to use cyclic executive to schedule tasks
	    with precedence relations?
	   If possible, please tell me how to do it.

I have several other questions about real-time scheduling.
	Q: Have you ever seen (or tried) scheduling several resources such
	   as CPU, communication media and so on, in an integrated fashion?
	   (For example, each task needs services from more than one resource.
	    Then how do you schedule these tasks to meet final deadlines?
	    More specifically, every task needs a service from cpu and then
	    I/O service. Then Is there any way to schedule cpu and I/O service
	    integratedly?)

	Q: The rate monotonic scheduling is known as optimal among fixed
	   priority schedulings.    Do you really use this scheduling
	   in real-time scheduling?    If not, I would like to know
	   why this is not used.    If used, please tell me when, how, 
	   and where the ratemonotonic scheduling can be used.

	Q: I think that there are two different kind of real-time tasks:
	   periodic and aperiodic.
	   What are examples of periodic tasks and what are those of aperiodic
	   tasks.   Can you tell me specific examples of these?

Thank you for your reading this message.

dbae@beach.cis.ufl.edu (Doohwan Bae) (04/12/90)

Hello!
I am a student working on real-time scheduling.
I have read a paper recently regarding ``cyclic executive'' used to schedule
real-time tasks.  The paper tell that cyclic executive can be used to
schedule tasks that have precedence relations, but I do not know of it.

So, my question is:
	Q: Is it possible to use cyclic executive to schedule tasks
	    with precedence relations?
           If possible, please tell me how to do it.

I have several other questions about real-time scheduling.
        Q: Have you ever seen (or tried) scheduling several resources such
	  as CPU, communication media and so on, in an integrated fashion?
          (For example, each task needs services from more than one resource.
	  Then how do you schedule these tasks to meet final deadlines?
	  More specifically, every task needs a service from cpu and then
	  I/O service. Then Is there any way to schedule cpu and I/O service
	  integratedly?)

	Q: The rate monotonic scheduling is known as optimal among fixed
	   priority schedulings.    Do you really use this scheduling
           in real-time scheduling?    If not, I would like to know
	   why this is not used.    If used, please tell me when, how,
	    and where the ratemonotonic scheduling can be used.

	Q: I think that there are two different kind of real-time tasks:
           periodic and aperiodic.
	   What are examples of periodic tasks and what are those of aperiodic
	     tasks.   Can you tell me specific examples of these?

Thank you for your reading this message.