SHORTEST REMAINING JOB FIRST
S.R.J.F.
Basic Theory :
The Shortest Remaining Job First (SRJF) is the preemptive version
of SJF scheduling.
In this scheduling algorithm, the process with the smallest amount of time remaining until completion is selected to execute. Processes having same arrival time will convert SRTF to SJF. It involves more overheads than SJF. It is faster in execution than SJF. It leads to increased throughput as execution time is less. When a process arrives to Request Queue, sort it in and select the SJF including the running process, possibly interrupting it (Remember: SJF schedules a new process only when the running is finished).
In this scheduling algorithm, the process with the smallest amount of time remaining until completion is selected to execute. Processes having same arrival time will convert SRTF to SJF. It involves more overheads than SJF. It is faster in execution than SJF. It leads to increased throughput as execution time is less. When a process arrives to Request Queue, sort it in and select the SJF including the running process, possibly interrupting it (Remember: SJF schedules a new process only when the running is finished).
- First, sort the processes in increasing order of their Arrival Time.
- Choose the process having least arrival time with least Burst Time. Then process it for 1 unit. Check if any other process arrives upto that time of execution or not.
- Repeat the above both steps until execute all the processes.