Operating System | Shortest Job First scheduling with predicted burst time

Prerequisite – CPU Scheduling, SJF – Set 1 (Non- preemptive), Set 2 (Preemptive)

Shortest Job First (SJF) is an optimal scheduling algorithm as it gives maximum Throughput and minimum average waiting time(WT) and turn around time (TAT) but it is not practically implementable because Burst-Time of a process can’t be predicted in advance.

We may not know the length of the next CPU burst, but we may be able to predict its value. We expect the next CPU burst will be similar in length to the previous ones. By computing an approximation of the length of the next CPU burst, we can pick the process with the shortest predicted CPU burst.

There are two methods by which we can predict the burst time of the process :

1. Static method – We can predict the Burst-Time by two factors :