What is Shortest Remaining Time First Method?
Shortest Remaining Time First (SRTF) is the preemptive version of Shortest Job Next (SJN) algorithm, where the processor is allocated to the job closest to completion.
This algorithm requires advanced concept and knowledge of CPU time required to process the job in an interactive system, and hence can’t be implemented there. But, in a batch system where it is desirable to give preference to short jobs, SRT algorithm is used.
However, SRT involves more overheads than SJN, as the OS is required to frequently monitor the CPU time of the jobs in the READY queue and perform context switching.
Characteristics of FCFS Scheduling
- It supports non-preemptive and pre-emptive scheduling algorithm.
- Jobs are always executed on a first-come, first-serve basis.
- It is easy to implement and use.
- This method is poor in performance, and the general wait time is quite high.
Advantages
- Many processes execute in less amount of time. So, throughput is increased.
- Processes which have short burst time run fast.
Disadvantages
- Practically it is not possible to predict the burst time.
- Processes which have long burst time will have to wait for long time for execution.