ODSA: A Novel Ordering Divisional Scheduling Algorithm for Modern Operating Systems

CPU scheduling is defined as scheduling multiple processes that are required to be executed in a specific time period. A large number of scheduling algorithms have been proposed to achieve maximum CPU utilization/throughput and minimizing turn around, waiting and response time. Existing studies claim that Round Robin (RR) is providing best results in terms of above-mentioned factors. In RR, a process is assigned to CPU for a fixed time quantum then the process starts its execution, in case that assigned time quantum greater than CPU’s capacity then remaining section of that process waits for its next turn. Although RR schedules processes in an efficient manner, however, it has certain limitations such as if time quantum is too small or large, it causes frequent context switching and response time can increase. To address these identified problems, various improved versions of RR also exist. The purpose of this paper is twofold: 1) a comparison between different improved versions of RR; and 2) a new algorithm named Ordering Divisional Scheduling Algorithm (ODSA) is also proposed that combines various features of different algorithms and is actually an improvement to RR. Our results show that ODSA can schedule processes with less turn around and average waiting time as compared to existing solutions. Keywords—CPU scheduling; round robin scheduling algorithm; turnaround time; waiting time; context switching