Question

5. [27pts.] Given the following set of processes, with arrival times, priorities, and the length of the CPU burst in ms: Priority Burst time Arrival Time Process 3 P1 4 P2 2 10 P3 P4 (Note: a lower number means higher priority) Draw a Gantt chart showing a FCFS scheduling algorithm. a. b. Draw a Gantt chart showing a non-preemptive Priority scheduling algorithm. c. Draw a Gantt chart showing a Round Robin Scheduling algorithm with quantum of 4ms d. Compute the average wait time for the FCFS algorithm. e. Compute the average wait time for the Round Robin Scheduling algorithm.

Answer 1

The answers for your question given below. If any doubts let me know.

a) FCFS Scheduling Algorithm

P1

P2

P3

P4

0                                    3                                    5                                     15                                 16

b) Non Pre-emptive Priority Scheduling Algorithm

P1

P2

P4

P3

0                                    3                            5                                    6                                   16

c) Round Robin Scheduling Algorithm

P1

P2

P3

P4

P3

P3

P3

0                   3                   5                    8                   9                    12                  15                16

d)

Turnaround Time = Completion time – Arrival time

P1 = 3 – 0 = 3

P2 = 5 – 1 = 4

P3 = 15 – 1 = 14

P4 = 16 – 1 = 15

Waiting Time = Turnaround Time – Burst Time

P1 = 3 – 3 = 0

P2 = 4 – 2 = 2

P3 = 14 – 10 = 4

P4 = 15 – 1 = 14

Average = (0 + 2 + 4 + 14) / 4 = 20 / 4 = 5

e)

Turnaround Time = Completion time – Arrival time

P1 = 3 – 0 = 3

P2 = 5 – 1 = 4

P3 = 16 – 1 = 15

P4 = 9 – 1 = 8

Waiting Time = Turnaround Time – Burst Time

P1 = 3 – 3 = 0

P2 = 4 – 2 = 2

P3 = 15 – 10 = 5

P4 = 8 – 1 = 7

Average = (0 + 2 + 5 + 7) / 4 = 14 / 4 = 3.5