Job scheduling guaranteing reasonable turn-around times

Summary

This report describes the algorithm for job scheduling and resource allocation used in the operating system Boss 2 for RC 4000. Most resources in the system are nonpreemptible, which causes the usual deadlock problems. The algorithm gives modest jobs a short turn-around time and more greedy jobs a correspondingly larger turn-around time. All jobs are guaranteed a finite turn-around time even if an infinite stream of other jobs is fed to the system (i.e. Holt's permanent blocking [7] is prevented). An estimate of the expected finishing time is computed when the job is enrolled. The estimate is updated continuously and is available from all terminals. The algorithm is a modification of the Banker's Algorithm described by Habermann [5]. It pays high attention to turnaround time and less attention to resource utilization.