Pre-emptive multitasking
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Pre-emptive multitasking is a form of multitasking. To understand the concept, compare to cooperative multiprocessing, in which only the active task (a.k.a. process) may initiate a context switch:
- Because the task has completed processing.
- Because the task has become blocked on a shared resource.
- Because the task is yielding the processor to another, similarly cooperative, task.
In pre-emptive multitasking, the Operating System kernel can also initiate a context switch to satisfy the scheduling policy's priority constraint, thus pre-empting the active task.
Usage: Pre-emptive multitasking is sometimes mistakenly used when the intended meaning is more specific, referring instead to the class of scheduling policies known as time-shared scheduling, or time-sharing.