design your example and give computation results of several cpu schedulers

Process          Burst Time

P1                8

P2                5

P3                1

P4                3

 

first-come, first-served ( FCFS ) scheduling algorithm:

average waiting time = ( 0+8+13+14) / 4 = 8.75 ms

 

shortest job first (SJF) scheduling algorithm:

average waiting time = ( 9+4+0+1 ) / 4 = 3.5 ms

 

Process      Arrival Time    Burst Time

P1           0              8

P2           1              5

P3           2              1

P4           3              3

 

round-robin ( RR ) scheduling algorithm:

average waiting time = ( ( 10 – 1 ) + ( 6 – 1 ) + 2 + 3 ) / 4 = 4.75