A New Hybrid Process Scheduling Algorithm (Pre-Emptive Modified Highest Response Ratio Next)
G. A. Shidali, Sahalu Balarabe Junaidu, Saleh El-Yakub Abdullahi · 2015
Highest Response Ratio Next (HRRN) scheduling is a non-preemptive discipline, in which the priority of each job is dependent on its estimated run time and the amount of time it has spent waiting. Jobs gain higher priority the longer they wait, which prevents indefinite postponement (process starvation). Also, the jobs that have spent a long time waiting compete against those estimated to have short run times. HRRN prevents indefinite postponements but is neither preemptive nor suitable for priority systems. In this research, HRRN has been modified to accommodate external priority and to include preemption. Hence, a preemptive modified HRRN (PMHRRN) algorithm has been developed.