the Priority Scheduling – Non-Preemptive solution for the given data.

Given Process Table

(Assume: lower priority number = higher priority)

Step-by-Step Scheduling (Non-Preemptive)

Time = 0

• Available: P1
• Execute P1 (only process available)

P1 runs from 0 → 5

Time = 5

Available processes:

• P2 (priority 5)
• P3 (priority 1)
• P4 (priority 2)

👉 Highest priority = P3

P3 runs from 5 → 7

Time = 7

Remaining processes:

• P2 (priority 5)
• P4 (priority 2)

👉 Highest priority = P4

P4 runs from 7 → 10

Time = 10

Remaining process:

• P2

P2 runs from 10 → 13

Gantt Chart

| P1 |  P3 |  P4 |  P2 |
0    5     7     10    13

Completion Time (CT)

Turnaround Time (TAT = CT − AT)

Waiting Time (WT = TAT − BT)

Average Times

• Average Waiting Time $$(0 + 2 + 6 + 8) / 4 = \mathbf{4}$$(0+2+6+8)/4=4
• Average Turnaround Time $$(5 + 4 + 9 + 11) / 4 = \mathbf{7.25}$$(5+4+9+11)/4=7.25

✅ This is the complete solution using Priority Scheduling (Non-Preemptive method).
If you want, I can also solve the preemptive version or convert this into exam-ready steps.

PROCESS ID ARRIVAL TIME BURST TIME PRIORITY P1 0 5 3 P2 2 3 5 P3 3 2 1 P4 1 3 2 above algorithm solved non priority and 5 is a highest priority

Below is the Priority Scheduling – Non-Preemptive solution when priority number 5 is the HIGHEST priority.

Given Process Table

(Higher number = Higher priority)

Step-by-Step Scheduling (Non-Preemptive)

Time = 0

Available process:

• P1

👉 Execute P1 (non-preemptive)

P1 runs from 0 → 5

Time = 5

Available processes:

• P2 (priority 5) ⭐
• P3 (priority 1)
• P4 (priority 2)

👉 Highest priority = P2

P2 runs from 5 → 8

Time = 8

Remaining processes:

• P3 (priority 1)
• P4 (priority 2)

👉 Highest priority = P4

P4 runs from 8 → 11

Time = 11

Remaining process:

• P3

P3 runs from 11 → 13

Gantt Chart

| P1 |  P2 |  P4 |  P3 |
0    5     8     11    13

Completion Time (CT)

Turnaround Time (TAT = CT − AT)

Waiting Time (WT = TAT − BT)

Average Times

• Average Waiting Time $$(0 + 3 + 7 + 8) / 4 = \mathbf{4.5}$$(0+3+7+8)/4=4.5
• Average Turnaround Time $$(5 + 6 + 10 + 10) / 4 = \mathbf{7.75}$$(5+6+10+10)/4=7.75

✅ Solved using Priority Scheduling (Non-Preemptive) where 5 is the highest priority.

Below is the Priority Scheduling – Preemptive solution
👉 Higher number = higher priority (5 is highest)

Given Process Table

Step-by-Step Execution (Preemptive)

Time 0

• Available: P1
• Execute P1

P1 runs from 0 → 2 (remaining BT = 3)

Time 2

• P2 arrives (priority 5 – highest)
  👉 Preempts P1

P2 runs from 2 → 5 (finishes)

Time 5

Available processes:

• P1 (remaining BT = 3, priority 3)
• P3 (BT = 2, priority 1)
• P4 (BT = 3, priority 2)

👉 Highest priority = P1

P1 runs from 5 → 8 (finishes)

Time 8

Remaining processes:

• P4 (priority 2)
• P3 (priority 1)

👉 Highest priority = P4

P4 runs from 8 → 11 (finishes)

Time 11

Remaining:

• P3

P3 runs from 11 → 13 (finishes)

Gantt Chart (Preemptive)

| P1 | P2 | P1 | P4 | P3 |
0    2    5    8    11   13

Completion Time (CT)

Turnaround Time

TAT = CT − AT

Waiting Time

WT = TAT − BT

Average Times

• Average Waiting Time

$$(3 + 0 + 7 + 8) / 4 = \mathbf{4.5}$$(3+0+7+8)/4=4.5

• Average Turnaround Time

$$(8 + 3 + 10 + 10) / 4 = \mathbf{7.75}$$(8+3+10+10)/4=7.75

✅ This is the correct Priority-Based Preemptive Scheduling solution where 5 is the highest priority.

If you want, I can also: