[cs33211] OS HW2 question

[Mikhail Nesterenko]

> I have a question about problem 5a from Homework2.
> 
> "A scheduler function of the OS manipulates the ready-queue of PCBs. *The
> scheduler can be run by any process in the system when this process is in
> kernel mode*. However, only one process running the scheduler code is
> allowed to manipulate the ready-queue at a time."
> 
> Does the underlined statement imply that *multiple* processes may be
> running the scheduler concurrently? The statement following it seems to
> concur with this notion.

Multiple processes can be executing the code of the scheduler. The
scheduler is just a set of functions in the OS that runs in the
context the process that is currently running and decides when and if
to switch to the next process and which process to switch to.

Now, it is not clear from the problem statement whether the computer
architecture where the OS is running has a single or multiple
processors or cores. I would like to leave it unclear. I do not
believe your answer should depend on it.

Thanks,
--
Mikhail