Nine Five And Two

Three jobs arrive on a single CPU. The scheduler is STCF (preemptive shortest time-to-completion first) and preempts the instant a shorter-remaining job becomes runnable. Context switches are free.

Job	Arrival (ms)	Run time (ms)
A	0	9
B	2	5
C	2	2

Recall $T_{turnaround} = T_{completion} - T_{arrival}$ and $T_{response} = T_{firstrun} - T_{arrival}$ .

What are the average turnaround time and the average response time?

Turnaround 9.67 ms, response 2.00 ms

Turnaround 8.33 ms, response 0.67 ms

Turnaround 11.67 ms, response 6.33 ms

Turnaround 10.67 ms, response 5.33 ms