FCFS(FIRST COME FIRST SERVED) question

Question 11

find the average Turn Around Time and Waiting Time of following processes using FCFS(FIRST COME FIRST SERVED) process scheduling algorithm?

Process	Arrival Time (AT)	Burst Time (BT)
P1	0	3
P2	2	6
P3	4	4
P4	6	5
P5	8	2
P6	9	7

Solution

Formulas :

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

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

Gantt Chart

Process	Arrival Time (AT)	Burst Time (BT)	Completion Time (CT)	Turn Around Time (TAT)	Waiting Time (WT)
P1	0	3	3	3	0
P2	2	6	9	7	1
P3	4	4	13	9	5
P4	6	5	18	12	7
P5	8	2	20	12	10
P6	9	7	27	18	11

Formulas:

• Average Turn Around Time (Average TAT) = Σ(TAT) / Number of Processes
• Average Waiting Time (Average WT) = Σ(WT) / Number of Processes

Average Turn Around Time (TAT) = (TAT1 + TAT2 + TAT3 + TAT4 + TAT5 + TAT6) / 6 = (3 + 7 + 9 + 12 + 12 + 18) / 6 = 61 / 6 = 10.17

Average Waiting Time (WT) = (WT1 + WT2 + WT3 + WT4 + WT5 + WT6) / 6 = (0 + 1 + 5 + 7 + 10 + 11) / 6 = 34 / 6 = 5.67

Question 12

find the average Turn Around Time and Waiting Time of following processes using FCFS(FIRST COME FIRST SERVED) process scheduling algorithm?

Process	Arrival Time (AT)	Burst Time (BT)
P1	0	5
P2	1	9
P3	2	6
P4	3	7
P5	5	4
P6	6	3

Solution

Formulas :

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

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

Gantt Chart

Process	Arrival Time (AT)	Burst Time (BT)	Completion Time (CT)	Turn Around Time (TAT)	Waiting Time (WT)
P1	0	5	5	5	0
P2	1	9	14	13	4
P3	2	6	20	18	12
P4	3	7	27	24	17
P5	5	4	31	26	22
P6	6	3	34	28	25

Formulas:

• Average Turn Around Time (Average TAT) = Σ(TAT) / Number of Processes
• Average Waiting Time (Average WT) = Σ(WT) / Number of Processes

Average Turn Around Time (TAT) = (TAT1 + TAT2 + TAT3 + TAT4 + TAT5 + TAT6) / 6 = (5 + 13 + 18 + 24 + 26 + 28) / 6 = 114 / 6 = 19.00

Average Waiting Time (WT) = (WT1 + WT2 + WT3 + WT4 + WT5 + WT6) / 6 = (0 + 4 + 12 + 17 + 22 + 25) / 6 = 80 / 6 = 13.33

Problem 13

find the average Turn Around Time and Waiting Time of following processes using FCFS(FIRST COME FIRST SERVED) process scheduling algorithm?

Process	Arrival Time (AT)	Burst Time (BT)
P1	0	2
P2	1	4
P3	2	8
P4	3	3
P5	4	7
P6	5	6

Solution

Formulas :

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

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

Gantt Chart

Process	Arrival Time (AT)	Burst Time (BT)	Completion Time (CT)	Turn Around Time (TAT)	Waiting Time (WT)
P1	0	2	2	2	0
P2	1	4	6	5	1
P3	2	8	14	12	4
P4	3	3	17	14	11
P5	4	7	24	20	13
P6	5	6	30	25	19

Formulas:

• Average Turn Around Time (Average TAT) = Σ(TAT) / Number of Processes
• Average Waiting Time (Average WT) = Σ(WT) / Number of Processes

Average Turn Around Time (TAT) = (TAT1 + TAT2 + TAT3 + TAT4 + TAT5 + TAT6) / 6 = (2 + 5 + 12 + 14 + 20 + 25) / 6 = 78 / 6 = 13.00

Average Waiting Time (WT) = (WT1 + WT2 + WT3 + WT4 + WT5 + WT6) / 6 = (0 + 1 + 4 + 11 + 13 + 19) / 6 = 48 / 6 = 8.00

Problem 14

find the average Turn Around Time and Waiting Time of following processes using FCFS(FIRST COME FIRST SERVED) process scheduling algorithm?

Process	Arrival Time (AT)	Burst Time (BT)
P1	0	6
P2	1	3
P3	2	5
P4	3	7
P5	5	4
P6	6	2

Solution

Formulas :

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

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

Gantt Chart

Process	Arrival Time (AT)	Burst Time (BT)	Completion Time (CT)	Turn Around Time (TAT)	Waiting Time (WT)
P1	0	6	6	6	0
P2	1	3	9	8	5
P3	2	5	14	12	7
P4	3	7	21	18	11
P5	5	4	25	20	16
P6	6	2	27	21	19

Formulas:

• Average Turn Around Time (Average TAT) = Σ(TAT) / Number of Processes
• Average Waiting Time (Average WT) = Σ(WT) / Number of Processes

Average Turn Around Time (TAT) = (TAT1 + TAT2 + TAT3 + TAT4 + TAT5 + TAT6) / 6 = (6 + 8 + 12 + 18 + 20 + 21) / 6 = 85 / 6 = 14.17

Average Waiting Time (WT) = (WT1 + WT2 + WT3 + WT4 + WT5 + WT6) / 6 = (0 + 5 + 7 + 11 + 16 + 19) / 6 = 58 / 6 = 9.67

Problem 15

find the average Turn Around Time and Waiting Time of following processes using FCFS(FIRST COME FIRST SERVED) process scheduling algorithm?

Process	Arrival Time (AT)	Burst Time (BT)
P1	0	7
P2	2	2
P3	4	6
P4	6	5
P5	8	3
P6	10	8

Solution

Formulas :

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

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

Gantt Chart

Process	Arrival Time (AT)	Burst Time (BT)	Completion Time (CT)	Turn Around Time (TAT)	Waiting Time (WT)
P1	0	7	7	7	0
P2	2	2	9	7	5
P3	4	6	15	11	5
P4	6	5	20	14	9
P5	8	3	23	15	12
P6	10	8	31	21	13

Formulas:

• Average Turn Around Time (Average TAT) = Σ(TAT) / Number of Processes
• Average Waiting Time (Average WT) = Σ(WT) / Number of Processes

Average Turn Around Time (TAT) = (TAT1 + TAT2 + TAT3 + TAT4 + TAT5 + TAT6) / 6 = (7 + 7 + 11 + 14 + 15 + 21) / 6 = 75 / 6 = 12.50

Average Waiting Time (WT) = (WT1 + WT2 + WT3 + WT4 + WT5 + WT6) / 6 = (0 + 5 + 5 + 9 + 12 + 13) / 6 = 44 / 6 = 7.33

Problem 16

find the average Turn Around Time and Waiting Time of following processes using FCFS(FIRST COME FIRST SERVED) process scheduling algorithm?

Process	Arrival Time (AT)	Burst Time (BT)
P1	1	4
P2	2	5
P3	3	6
P4	4	7
P5	5	8
P6	6	9

Solution

Formulas :

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

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

Gantt Chart

Process	Arrival Time (AT)	Burst Time (BT)	Completion Time (CT)	Turn Around Time (TAT)	Waiting Time (WT)
P1	1	4	5	4	0
P2	2	5	10	8	3
P3	3	6	16	13	7
P4	4	7	23	19	12
P5	5	8	31	26	18
P6	6	9	40	34	25

Formulas:

• Average Turn Around Time (Average TAT) = Σ(TAT) / Number of Processes
• Average Waiting Time (Average WT) = Σ(WT) / Number of Processes

Average Turn Around Time (TAT) = (TAT1 + TAT2 + TAT3 + TAT4 + TAT5 + TAT6) / 6 = (4 + 8 + 13 + 19 + 26 + 34) / 6 = 104 / 6 = 17.33

Average Waiting Time (WT) = (WT1 + WT2 + WT3 + WT4 + WT5 + WT6) / 6 = (0 + 3 + 7 + 12 + 18 + 25) / 6 = 65 / 6 = 10.83

Problem 17

find the average Turn Around Time and Waiting Time of following processes using FCFS(FIRST COME FIRST SERVED) process scheduling algorithm?

Process	Arrival Time (AT)	Burst Time (BT)
P1	0	4
P2	1	6
P3	2	8
P4	3	3
P5	4	5
P6	5	2

Solution

Formulas :

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

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

Gantt Chart

Process	Arrival Time (AT)	Burst Time (BT)	Completion Time (CT)	Turn Around Time (TAT)	Waiting Time (WT)
P1	0	4	4	4	0
P2	1	6	10	9	3
P3	2	8	18	16	8
P4	3	3	21	18	15
P5	4	5	26	22	17
P6	5	2	28	23	21

Formulas:

• Average Turn Around Time (Average TAT) = Σ(TAT) / Number of Processes
• Average Waiting Time (Average WT) = Σ(WT) / Number of Processes

Average Turn Around Time (TAT) = (TAT1 + TAT2 + TAT3 + TAT4 + TAT5 + TAT6) / 6 = (4 + 9 + 16 + 18 + 22 + 23) / 6 = 92 / 6 = 15.33

Average Waiting Time (WT) = (WT1 + WT2 + WT3 + WT4 + WT5 + WT6) / 6 = (0 + 3 + 8 + 15 + 17 + 21) / 6 = 64 / 6 = 10.67

Problem 18

find the average Turn Around Time and Waiting Time of following processes using FCFS(FIRST COME FIRST SERVED) process scheduling algorithm?

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

Solution

Formulas :

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

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

Gantt Chart

Process	Arrival Time (AT)	Burst Time (BT)	Completion Time (CT)	Turn Around Time (TAT)	Waiting Time (WT)
P1	0	4	4	4	0
P2	1	5	9	8	3
P3	2	6	15	13	7
P4	3	7	22	19	12
P5	4	8	30	26	18
P6	5	9	39	34	25

Formulas:

• Average Turn Around Time (Average TAT) = Σ(TAT) / Number of Processes
• Average Waiting Time (Average WT) = Σ(WT) / Number of Processes

Average Turn Around Time (TAT) = (TAT1 + TAT2 + TAT3 + TAT4 + TAT5 + TAT6) / 6 = (4 + 8 + 13 + 19 + 26 + 34) / 6 = 104 / 6 = 17.33

Average Waiting Time (WT) = (WT1 + WT2 + WT3 + WT4 + WT5 + WT6) / 6 = (0 + 3 + 7 + 12 + 18 + 25) / 6 = 65 / 6 = 10.83

Problem 19

find the average Turn Around Time and Waiting Time of following processes using FCFS(FIRST COME FIRST SERVED) process scheduling algorithm?

Process	Arrival Time (AT)	Burst Time (BT)
P1	0	3
P2	1	4
P3	2	5
P4	3	6
P5	4	7
P6	5	8

Solution

Formulas :

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

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

Gantt Chart

Process	Arrival Time (AT)	Burst Time (BT)	Completion Time (CT)	Turn Around Time (TAT)	Waiting Time (WT)
P1	0	3	3	3	0
P2	1	4	7	6	2
P3	2	5	12	10	5
P4	3	6	18	15	9
P5	4	7	25	21	14
P6	5	8	33	28	20

Formulas:

• Average Turn Around Time (Average TAT) = Σ(TAT) / Number of Processes
• Average Waiting Time (Average WT) = Σ(WT) / Number of Processes

Average Turn Around Time (TAT) = (TAT1 + TAT2 + TAT3 + TAT4 + TAT5 + TAT6) / 6 = (3 + 6 + 10 + 15 + 21 + 28) / 6 = 83 / 6 = 13.83

Average Waiting Time (WT) = (WT1 + WT2 + WT3 + WT4 + WT5 + WT6) / 6 = (0 + 2 + 5 + 9 + 14 + 20) / 6 = 50 / 6 = 8.33

Problem 20

find the average Turn Around Time and Waiting Time of following processes using FCFS(FIRST COME FIRST SERVED) process scheduling algorithm?

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

Solution

Formulas :

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

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

Gantt Chart

Process	Arrival Time (AT)	Burst Time (BT)	Completion Time (CT)	Turn Around Time (TAT)	Waiting Time (WT)
P1	0	4	4	4	0
P2	1	5	9	8	3
P3	2	6	15	13	7
P4	3	7	22	19	12
P5	4	8	30	26	18
P6	5	9	39	34	25

Formulas:

• Average Turn Around Time (Average TAT) = Σ(TAT) / Number of Processes
• Average Waiting Time (Average WT) = Σ(WT) / Number of Processes

Average Turn Around Time (TAT) = (TAT1 + TAT2 + TAT3 + TAT4 + TAT5 + TAT6) / 6 = (4 + 8 + 13 + 19 + 26 + 34) / 6 = 104 / 6 = 17.33

Average Waiting Time (WT) = (WT1 + WT2 + WT3 + WT4 + WT5 + WT6) / 6 = (0 + 3 + 7 + 12 + 18 + 25) / 6 = 65 / 6 = 10.83