Question

Five processes arrive to run on a CPU. The scheduler puts them in its data structure. The table below lists the processes, how much CPU time each will need, and the priority of each process. One(1) is the highest priority and 4 is the lowest priority. Process CPU time needed Priority P1 P2 P3 NNW-W a. The scheduler uses First Come First Serve to schedule the jobs. Fill in the time line below showing at what time each process starts and finished. Ignore process switching overhead. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 b. The scheduler uses Shortest Job First to schedule the jobs. Fill in the time line below showing at what time each process starts and finished. Ignore process switching overhead. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 c. The scheduler uses Round Robin to schedule the jobs. Fill in the time line below showing at what time each process starts and finished. Ignore process switching overhead. Assume a time quantum of 1 unit. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 es Priority il in the time ligwitching o d. The scheduler uses Priority Scheduling (1st) and Round Robin (2nd) within the queues to schedule the jobs. Fill in the time line below showing at what time each process starts and finished. Ignore process switching overhead. Assume a time quantum of 1 unit. 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20

Answer 1

Answer a): First Come First Serve Shedular :

we schedule first job first and continue its execution until it completes.

P1	P1	P1	P1	P2	P2	P2	P3	P3	P4	P4	P4	P4	P4	P5
0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20

Answer b) Shortest Job First:

we schwdule shortest job among the all job first and continue its execution until it completes.

P5	P3	P3	P2	P2	P2	P1	P1	P1	P1	P4	P4	P4	P4	P4
0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20

Answer c)Round Robbin

we schedule all job with the time quantum 1 as per first come firt serve basis we repeat scheduling until it completes.

P1	P2	P3	P4	P5	P1	P2	P3	P4	P1	P2	P4	P1	P4	P4
0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20

Answer d)Priority Scheduling and Round Robbin

we schedule all job with their Priority and apply time quantum 1, we repeat scheduling until it completes.

P2	P4	P5	P1	P3	P2	P4	P1	P3	P2	P4	P1	P4	P1	P4
0	1	2	3	4	5	6	7	8	9	10	11	12	13	14	15	16	17	18	19	20