Scheduling Algorithms

Ways of assigning priorities dynamically (internally)

Highest Response Ratio Next (HRN)

One method for doing this is as follows: For each job, calculate its priority as

priority = ( time waiting + service time ) / ( service time )

where a higher numerical value means a higher priority.

The name comes from the fact that the numerator represents the total turnaround time/response time for the job if it is given the processor now, while the denominator is the actual time needed. The response ratio is the ratio of actual turnaround time to time needed.