Modified Pre-emptive Priority-Based Round Robin Scheduling Algorithms with Dynamic Time Quantum: MPPBRRACBDQ and MPPBRRALBTDQ

Scheduling is an essential part of an operating system. The main aim of scheduling is to schedule jobs and allot them to the CPU in a balanced way. It follows a set of rules to give prioritization to various processes. This would ensure that a system serves all requests and would achieve a certain quality of service with the existing hardware. In this paper, analysis of two Round Robin Scheduling Algorithms is carried out and modifications are made to improve the two algorithms which result in a quicker completion of the processes. The performance of the proposed algorithms, MPPBRRACBDQ and MPPBRRALBTDQ, is analyzed by comparing with existing well-known algorithms such as FCFS, SJF, PS and RR and also OMDRRS (Goel et al. in Int J Adv Comput Sci Appl 7:216–221, 2016) and improved Round Robin ( H. B. Parekh, S. Chaudhari (2016) Improved round robin CPU scheduling algorithm. International Conference on Global Trends in Signal Processing, Information Computing and Communication, 184–187.). In MPPBRRACBDQ, the time quantum is varied dynamically based on the remaining burst time and is multiplied by two, while in MPPBRRALBTDQ, the time quantum is dynamically assigned based on the burst time, i.e., the least burst time among the processes is chosen to be the time quantum. The results prove that the new proposed algorithms perform better than the existing algorithms. Notable improvements are observed in waiting time (WT), turnaround time (TAT) and the number of context switches. The TAT, WT and context switches are compared and graphically represented. This research is an attempt to enhance the efficiency of the scheduling by developing and implementing new scheduling algorithms.