Free CPU scheduling lessonsCPU scheduling · Stage 0 · The scheduler's job · Step 1
Why the OS needs a scheduler
See why processes take turns on the CPU, who decides, and when the decision happens. About 12 minutes.
A process has asked for a disk read and is waiting for it. Where is it?
- AIn the waiting state, not in the ready queue
- BIn the ready queue
- CStill running, holding the CPU
Show the answer
In the waiting state, not in the ready queue. It can't use the CPU until the read completes, so the scheduler doesn't consider it.
4 questions on this idea
Short questions that apply the idea to new cases: trace it, work out a number, put steps in order. A wrong answer explains itself.
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