Which is the correct definition of a valid process transition in an operating…
2009
Which is the correct definition of a valid process transition in an operating system?
Answer: B. Dispatch: ready → running — A process's lifecycle is governed by a fixed state diagram (New, Ready, Running, Blocked/Waiting, Terminated) in which every edge is caused by exactly one…
- A.
Wake up: ready → running
- B.
Dispatch: ready → running
- C.
Block: ready → running
- D.
Timer runout: ready → running
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Correct answer: B
A process's lifecycle is governed by a fixed state diagram (New, Ready, Running, Blocked/Waiting, Terminated) in which every edge is caused by exactly one uniquely-named scheduling event — no two events share the same transition, so identifying the event correctly identifies the transition.
Mapping each event named in the options to the transition it actually causes:
Event | Actual transition |
|---|---|
Dispatch | Ready → Running (CPU scheduler picks the process to run) |
Wake up | Blocked → Ready (an awaited event/resource becomes available) |
Block | Running → Blocked (process requests I/O or waits on an event) |
Timer runout | Running → Ready (time slice expires; preemption) |
Only Dispatch is defined as Ready → Running; Wake up, Block, and Timer runout are each mislabeled in the other options against their true transitions above, so Dispatch: ready → running is the only option whose event and transition genuinely match.
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