Question

Given the following mix of job, job lengths, and arrival times, assume a time slice of 10 and compute the completion for each job and average response time for the FCFS, SJN, SRT, and Round Robin Scheduling Algorithm.

jobs arrival time CPU cycle(ms)

A 0 16

B 3 2

C 5 11

D 9 6

E 10 1

F 12 9

G 14 4

H 16 14

I 17 1

J 19 8

Answer 1

1.FCFS

A

B

C

D

E

F

G

H

I

J

0-------16----------18---------29---------35---------36--------45---------49----------63----64-----72

completion time

A - 16, B - 18, C- 29 , D- 35, E - 36, F - 45, G - 49 , H - 63 , I - 64 , J - 72

Average Response Time = (0+16+18+29+35+36+45+49+63+64)/10 = 35.5

2. SJN

A

E

I

B

G

D

J

C

F

H

0---------16--------17----18-------20-----------24---------30------38---------49--------58---------72

completion time

A - 16, B - 20, C- 49 , D- 30, E - 17, F - 58, G - 24 , H - 72 , I - 18 , J - 38

Average Response Time = (0+18+38+24+16+49+20+58+17+30)/10 = 27

3.SRT

A

B

C

D

E

D

G

I

C

J

F

A

H

0-----3--------5--------9------10-------11------16-------20--21------28---36-------45-----58------72

completion time

A - 58, B - 5, C- 28 , D- 16, E - 11, F - 45, G - 20 , H - 72 , I - 21 , J - 36

Average Response Time = (0+3+5+9+10+36+16+58+20+28)/10 = 18.5

4.RR

A

B

C

D

E

F

G

H

I

J

A

C

H

0-----10------12------22------28------29------38-----42-------52---53---61-----67-------68-----72

completion time

A - 67, B - 12, C- 68 , D- 28, E - 29, F -38, G - 42 , H - 72 , I - 53 , J - 61

Average Response Time = (0+10+12+22+28+29+28+42+52+53)/10 = 27.6

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