Exercise (4)

Exercise

• Assume the following jobs are executed with one processor, with the jobs arriving in the order listed in the table.– Suppose a system uses FCFS scheduling. Create a Gantt

chart illustrating these processes.

– What is the turnaround time for process p3?

– What is the average waiting time for processes?

– How about Shortest-Job-Next (SJN) scheduling?

2

i (pi)

0 80

1 20

2 10

3 20

4 50

3

p1 p2 p3

Avg. waiting time of FCFS is:

i (pi)

0 80

1 20

2 10

3 20

4 50

p0

p4

0

Avg. waiting time of SJN is:

0

FCFS:

SJN:

Turnaround time of process p3 with FCFS:

Turnaround time of process p3 with SJN: