how to determing lenngh of next cpu burst ??

Question

Three processes have the cpu burst times 5,4,3 ms respectively .what will be the predicted value of the next processs cpu burst in milliseconds for shortest job first sheduling ?

Ans: 3.125 i am getting 3.85 ??

Comments

then question is not correct

no need to worry about

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Thanks

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Is arrival time of jobs required to solve this question?

prediction of B.T may be either static ( process Type or Process Size ) or dynamic ( simple averaging, aging). in all these four methods it is independent of arrival time then why we require arrival time of jobs to solve this question. Of course smoothening factor and intial guess is required if the question is solved in aging method.

Am I right Srestha Mam ?

Answer 1

The above is a question of SJF with the prediction of BT. It is incomplete though. If I use simple averaging then:

(5+4+3)/3 = 4       which is right if I followed this method.

For using exponential averaging we need, α: smoothening factor and τ1: predicted burst of process 1.

How did you get 3.85? Maybe I'm wrong somewhere.