The scheduling of multiple disk drives

Abstract

Techniques for scheduling disk drives are of two types: those which schedule transfers (based on rotational position) and those which schedule seeks (based on cylinder position). A simulation model has been developed to evaluate both of these approaches in a multiple drive environment. Use of this model for a comparison of two techniques for transfer scheduling has recently been reported [13]. This paper presents additional results of that study and extends it with a preliminary exploration of seek scheduling effects. The results indicate that seek scheduling can be effective for large configurations only when used in conjunction with a transfer scheduling technique.