Q82.Marks: +2.0UGC NET Paper 2: Computer Sc 6th Jan 2025 Shift 1
Given the following processes with their times and priority (lower number indicates higher priority)
Process
Burst Time
Priority
P1
10
3
P2
1
1
P3
2
4
P4
1
5
P5
8
2
Which of the following is a value of average waiting time using priority scheduling algorithm?
1.9.2
2.6.8
3.7.6
4.10.0✓ Correct
Solution
Concept:
In Priority Scheduling (Non-Preemptive), the process with the highest priority (i.e., lowest numerical value) is scheduled first. If two processes have the same priority, FCFS (First-Come-First-Serve) is used.
FORMULAE:
TAT = CT − AT
WT = TAT − BT
AT (Arrival Time) is assumed to be 0 for all processes in this question.
Analysis:
GANTT CHART: P₂ → P₅ → P₁ → P₃ → P₄
Pid
BT
Priority
CT
TAT
WT
P₂
1
1
1
1
0
P₅
8
2
9
9
1
P₁
10
3
19
19
9
P₃
2
4
21
21
19
P₄
1
5
22
22
21
Average Waiting Time =\(\frac{0 + 1 + 9 + 19 + 21}{5} = \frac{50}{5} = 10.0\)
Hence, the correct answer is: option 4. The accurate average waiting time is 10.0 units.