Problem $5$: Measurements of a certain system have shown that the average process runs for a

time $T$ before blocking on I$/$O$.$ A process switch requires a time $S,$ which is wasted $($overhead$).$

The CPU efficiency equals the CPU execution time of user processes divided by the total CPU

time. For round$-$robin scheduling with quantum $Q,$ give a formula for the CPU efficiency for

each of the following: $(20$ pts$)$

$($a$)Q=$

$($b$)Q>T$

$($c$)Q=SS$

$(d)Q=S$

$(e)Q$ nearly $0$