Below is a table of jobs that we must schedule on a batch operating system. All jobs are available from the start.
Job Arrival time Run time
J1 0 5 seconds
J2 0 6 seconds
J3 0 1 second
J4 0 2 secondsCreate a time-line to illustrate the First-Come First-Served (FCFS) strategy. It should include the start/stop times of each job.
Just run the jobs in the order given:
J1 J2 J3 J4
|----------|------------|--|----|-->
0 5 11 12 14Compute the average turnaround time of the four jobs using your FCFS time-line from the previous question.
Turnaround is completion minus arrival time.
J1: 5 - 0 = 5
J2: 11 - 0 = 11
J3: 12 - 0 = 12
J4: 14 - 0 = 14
Sum is 5 + 11 + 12 + 14 = 42
So average is 42 ÷ 4 = 10.5Create a time-line to illustrate the Shortest Job Next (SJN) strategy. It should include the start/stop times of each job.
J3 J4 J1 J2
|--|----|----------|------------|-->
0 1 3 8 14Compute the average turnaround time of the four jobs using your SJN time-line from the previous question.
J1: 8 - 0 = 8
J2: 14 - 0 = 14
J3: 1 - 0 = 1
J4: 3 - 0 = 3
Sum is 8 + 14 + 1 + 3 = 26
So average is 26 ÷ 4 = 6.5