> >KeyKOS used meters to freeze a process. You could use schedules.
>
> But in that case you have to take priority inheritance into consideration.
> You can no longer stop a thread merely by revoking its source of CPU time:
> if another thread tries to make a call to it, it may donate its own
> source of CPU time, and the "stopped" thread will run anyway.
> Of course, if priority inheritance can be disabled on a thread-by-thread
> basis, you can solve this simply by revoking the schedule _and_
> disabling priority inheritance on the thread.
The idea that meters provided a connection like power lines to a utility rather than like being given batteries which you could draw down whenever you wanted to was central to their design. I have not considered what would happen if this assumption were changed for many years. There are many people who feel that meters are not adaquate to solve all scheduling problems (being too inefficent), but as far as I know, no one has ever made a serious effort to implement any scheduling policy using meters and measure it.
Bill Frantz Periwinkle -- Computer Consulting (408)356-8506 16345 Englewood Ave. frantz@netcom.com Los Gatos, CA 95032, USA