Question

Topic Round Robin

Answer the following using the First Come First Serve Scheduling Algorithm SHOW COMPLETE SOLUTION 1. Process AT BT P1 1 10 P2 0 15 P3 2 8 P4 5 7 P5 6 5 P6 9 3 P7 8 4 P8 3 5 P9 4. 20

Answer 1

FIrst Come First Serve scheduling executes the process according to their arrival time. The process which comes first or arrive early will be executed first. So let's arrange the process according to their arrival time.

Process	Arrival Time(AT)	Burst Time(BT)
P2	0	15
P1	1	10
P3	2	8
P8	3	5
P9	4	20
P4	5	7
P5	6	5
P7	8	4
P6	9	3

Now Let's find out the completion time of each process

Process which arrives at t = 0 will take burst time to complete while for other process completion time of process executed before plus their burst time must be considered to find the completion time.

Now finding completion time of each process using the above table.

Process	Arrival Time(AT)	Burst Time(BT)	Completion TIme(CT)
P2	0	15	BT = 15 CT2 = 15
P1	1	10	CT1 = Previous Process Completion Time(CT2) + Burst Time CT1 = 15 + 10 CT1 = 25
P3	2	8	CT3 = 25 + 8 CT3 = 33
P8	3	5	CT8 = 33 + 5 CT8 = 38
P9	4	20	CT9 = 38 + 20 CT9 = 58
P4	5	7	CT4 = 58 + 7 CT4 = 65
P5	6	5	CT5 = 65 + 5 CT5 = 70
P7	8	4	CT7 = 70 + 4 CT7 = 74
P6	9	3	CT6 = 74 + 3 CT6 = 77

Let's find out the turn around time and waiting time for each process->

Turn Around Time (TAT) = Completion Time (CT) - Arrival Time(AT)

Waiting Time (WT) = TAT - Burst Time(BT)

Process	Arrival Time(AT)	Burst Time(BT)	Completion TIme(CT)	Turn Around Time(TAT) = CT - AT	Waiting Time(WT) = TAT - BT
P2	0	15	15	15 - 0 = 15	15 - 15 = 0
P1	1	10	25	25 - 1 = 24	24 - 10 = 14
P3	2	8	33	33 - 2 = 31	31 - 8 = 23
P8	3	5	38	38 - 3 = 35	35 - 5 = 30
P9	4	20	58	58 - 4 = 54	54 - 20 = 34
P4	5	7	65	65 - 5 = 60	60 - 7 = 53
P5	6	5	70	70 - 6 = 64	64 - 5 = 59
P7	8	4	74	74 - 8 = 66	66 - 4 = 62
P6	9	3	77	77 - 9 = 68	68 - 3 = 65

Average Waiting Time = 0 + 14 + 23 + 30 + 34 + 53 + 59 + 62 + 65 / 9

= 37.77

GANTT CHART:

P2

P1

P3

P8

P9

P4

P5

P7

P6

0 15 25 33 38 58 65 70 74 77