FCFS - First Come First Serve. The Gantt chart can be used to find the finish times for this non-preemptive scheduling algorithm.
Gantt Chart:+------------------------------------+ | P1 | P2 | P3 | +------------------------------------+ 0 4 10 14 Time 0 1 2 4 READY P1 P2 P2 P2 ... P3 P3
From the Gantt chart, finish times are:
Process | Finish | Wait |
---|---|---|
P1 | 4 | 0 |
P2 | 10 | 3 |
P3 | 14 | 8 |
So, for example, the wait time for P3 is:
Wait = Finish - Arrival - CPU_Burst = 14 - 2 - 4 = 8
and the average wait time for these three:
Avg. Wait = (0 + 3 + 8)/3 = 3.667