Q:design your example  and give computation results of several cpu schedulers

A:

P1:7 P2:3 P3:6 P4:2 P5:9

FCFS:

order: P(1, 2, 3, 4,  5)

average waiting time = (7 + 10 + 16+ 18) / 5 = 10.2

SJF:

order: P(4, 2, 3, 1,  5)

average waiting time = (2 + 5 + 11 + 18) / 5 = 6.4

PSA:

given priority P1:4 P2:1 P3:2 P4:3 P5:5

order: P(2, 3, 4, 1,  5)

average waiting time = (3 + 9 + 11 + 18) / 5 = 8.2