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Consider the following justifications for commonly using the two-level $CPU$ scheduling:

I. It is used when memory is too small to hold all the ready processes.

II. Because its performance is same as that of the $FIFO$.

III. Because it facilitates putting some set of processes into memory and a choice is made from that.

IV. Because it does not allow to adjust the set of in-core processes.

Which of the following is true ?

  1. $I, III$ and $IV$
  2. $I$ and $II$ 
  3. $III$ and $IV$
  4. $I$ and $III$ 
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1 Answer

1 vote

Answer : D

Two-level scheduling uses two different schedulers, one lower-level scheduler which can only select among those processes in memory to run. That scheduler could be a Round-robin scheduler. The other scheduler is the higher-level scheduler whose only concern is to swap in and swap out processes from memory.

Reference : Two-level scheduling 

Answer:

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