Prioritized Fair Round Robin Algorithm with Variable Time Quantum

The performance of the time sharing systems and multiprocessor systems is greatly dependent on CPU scheduling algorithms. Some of the famous algorithms are Shortest Job First (SJF), First Come First Served (FCFS), Priority Scheduling and Round Robin (RR). Round Robin is the preferable choice for time shared systems. The main aim of this paper is to formulate a new methodology for RR algorithm that enhances the performance of the time sharing systems by reducing the waiting time, turnaround time and number of context switches. The proposed algorithm Prioritized Fair Round Robin (PFRR) with variable time quantum is a combination of SJF, Priority Scheduling, and RR with variable time quantum. The idea is to set the time quantum value according to the priority and burst times of the processes in the ready queue. The algorithm is designed for both equal priority processes and different priority processes.