UGC NET CSE | December 2014 | Part 2 | Question: 36

Question

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 ?

• A. $I, III$ and $IV$
• B. $I$ and $II$ 
• C. $III$ and $IV$
• D. $I$ and $III$ 

Answer 1

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