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An operating system uses shortest remaining time (SRT) scheduling algorithm. Consider the arrival times and execution time for the following processes: Proces Arrival Time Execution Time P1 0 20 P2 15 25 P3 30 10 P4 45 15 What is total waiting time for process P2?

An operating system uses shortest remaining time (SRT) scheduling algorithm. Consider the arrival times and execution time for the following processes: Proces Arrival Time Execution Time P1 0 20 P2 15 25 P3 30 10 P4 45 15 What is total waiting time for process P2? Correct Answer 15

Shortest remaining time (SRT)  is pre-emptive algorithms

Gantt chart:

P1

P2

P3

P2

  P4

0      20      30      40     55      70

Process Table:

Process

Arrival Time

Execution Time (Burst Time)

 Completion Time  Turnaround time  Waiting time

P1

0

20

      

P2

15

25

 55 40 15

P3

30

10

      

P4

45

15

      
 

Explanation:

Completion time For P2 =55

Turn around time (TAT) = Completion time - Arrival time = 55 -15 = 40

Waiting Time for P2  = TAT-Execution Time = 40- 25 =15

Therefore waiting time P2 is 15 unit:

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