Question

A uni-processor computer system only has two processes, both of which alternate 10 ms CPU bursts with 90 ms I/O bursts. Both the processes were created at nearly the same time. The I/O of both processes can proceed in parallel. Which of the following scheduling strategies will result in the least CPU ulitization (over a long period of time) for this system?

Answer 1

CPU = 10 ms
I/O = 90 ms

FCFS

So CPU idle time is 80
Round Robin

CPU idle time is 85.
Therefore, round robin scheduling with a time quantum of 5ms has least CPU utilization.