CPU burst time indicates the time, the process needs the CPU. The following are the set of processes with their respective CPU burst time (in milliseconds).

Calculate the average waiting time if the process arrived in the following order:

(i) P1, P2 & P3 


Ans:
Considering FCFS scheduling
Process      Burst Time
P1                   10
P2                    5 
P3                    5 

(i) Suppose that the processes arrive in the order: P1 , P2 , P3 The Gantt Chart for the schedule is: 

Waiting time for P1 = 10; P2 = 0; P3 = 5

Average waiting time: (10 + 0 + 5)/3 = 5 unit of time.