Given the Burst Time (BT) of 4 processes P1, P2, P3 and P4 as BT(t1, t2, t3,…
2017
Given the Burst Time (BT) of 4 processes P1, P2, P3 and P4 as BT(t1, t2, t3, t4) = (4, 8, 6, 7), smoothing factor(α) = 0.5, and T1 = 10, what will be the burst time of process P5 for Shortest Job First scheduling, using the technique of exponential averaging?
- A.
6.875 unit time
- B.
6.25 unit time
- C.
5.785 unit time
- D.
5.5 unit time
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Show answer & explanation
Correct answer: A
The next burst time Tn+1 is predicted using the exponential averaging formula:
Tn+1 = α tn + (1 - α) . Tn
Given α = 0.5 and T1 = 10:
For P2 (T2): 0.5(4) + 0.5(10) = 7
For P3 (T3): 0.5(8) + 0.5(7) = 7.5
For P4 (T4): 0.5(6) + 0.5(7.5) = 6.75
For P5 (T5): 0.5(7) + 0.5(6.75) = 6.875
Thus, the predicted burst time for P5 is 6.875 unit time. Correct option is A.