Assume that the following jobs are to be executed on a single processor…
2021
Assume that the following jobs are to be executed on a single processor system. All jobs have arrived at 0 msec.
If the system uses Shortest Job First (SJF) scheduling, then calculate the average waiting time of the jobs.
- A.
4
- B.
2.75
- C.
7
- D.
11
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Correct answer: B
Using Shortest Job First (SJF) scheduling, processes are executed in increasing order of burst time.
Burst times:
b = 1, d = 2, a = 4, c = 7
Execution order:
b → d → a → c
Waiting times:
• b = 0
• d = 1
• a = 1 + 2 = 3
• c = 1 + 2 + 4 = 7
Average waiting time: 7+3+1+0 /4 = 2.75 ms
So, the average waiting time is 2.75 ms.