SJF Algorithm



2 – SJF ( Shortest Job First ) Or SPN  ( Short Process Next)



process
Burst Time
P1
10
P2
5
P3
20
P4
10




  SJF        P2          p1          p4          p3
CPU |-----------|-----------|-----------|-----------|
       0            5            15           25          45



TA  = Time End Process – 0 (Arrival Time)

TA1= 15 – 0 = 15
TA2= 5 – 0 = 5
                            TA Average           è  90/4 = 18.75
TA3= 45 – 0 = 45
TA4= 25 – 0 = 25


WT = Wait Time Process – 0 (Arrival Time)

WT1 = 5 – 0 =  5
WT2 = 0 – 0 = 0
                          WTAverage          è   45/4 = 11.25                  
WT3 = 25 – 0 = 25
WT4 = 15 – 0 = 15

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