OS Scheduler

Shortest Remaining Time (SRT)

Shortest Remaining Time is the Preemptive version of SPN policy.

Must estimate processing time.

The scheduler may preempt the current process when a new process becomes ready. As with SPN, the scheduler must have an estimate of processing time to perform the selection function.

Danger: Starvation of long processes (same as SPN).


  • Better general turn-around time than SPN (because we now have Preemption)
  • No bias for long processes like in FCFS


  • Elapsed service time must be recorded