 
Shortest
Processing Time (SPT) :
The shortest job are handled first and completed.
The step for using this rule are:
 Firstly, the user will input the number of jobs, the job names,the
processing time and the due date of each job or use the data values given at the starting
point. 
 The second step is sorting out the shortest processing time among the jobs. 
 Thirdly, calculate the flow time of each job by using the processing time.
the flow time is the accummulations of processing time each job by each job. 
 The delays is calculated from the flow time and due date.
The formula is:
Delay = Flow time  due date
However, there are two conditions for calculating the delays
although apply the formula already:
If the delays calculated is less than flow time, then the delays = zero.
If the delays calculated is more than flow time, then the delays =
the value of (flow time  due
date).

 The next step is calculating the total processing time, total flow
time and total delays from the accummulations processing time, the accummulations flow
time and the accummulations delays. 
 Then, using the total flow time, total processing time, and total
delays for calculating the average completion time, the utilisation, the average number of
jobs in the system and the average job delays. 
 The formulas for calculation are below:
Average completion time = sum of total flow / no. of
jobs
Utilisation = total processing time / sum of total flow
Average no. of jobs = total flow time / total
processing time
Average job delays = total delays / no. of jobs

 These above are the steps for using the SPT priority rules. 
Demo Using SPT in Example
Back to Solution by Using
SPT
Example
of SPT Method
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[Priority Rules] [Types
of Priority Rules] [FCFS]
[EDD] [SPT]
[LPT] [CR]
