Highest Response Ratio Next (HRRN) Scheduling in Operating Systems

Highest response ratio next is an algorithm based on the value of the response ratio where response ratio is equals to division of (waiting time + burst time) and burst time. HRRN algorithm is a non-preemptive algorithm and it is considered to be one of the most optimal scheduling algorithms. It is a modification of the shortest Job Scheduling algorithm. It aims to reduce the problem of starvation among waiting processes. 

This algorithm reduces the waiting time of processes having long burst times. It solves the starvation problem of processes in the ready queue. It performs better than the SJF CPU scheduling algorithm. It prefers jobs with smaller burst times for scheduling next on the CPU. 

HRRN algorithm requires calculating the response ratio for each process. However, RR utilizes burst times of a process and it is not possible to know the burst times of all the processes in advance. HRRN is difficult to implement this algorithm in real-life. HRRN algorithm may lead to an extra overhead on the CPU due to the calculation of RR for each process arriving in the system.

HRRN algorithm:
https://www.geeksforgeeks.org/highest-response-ratio-next-hrrn-cpu-scheduling/