A Power-Effective Design of Auto-Sleep Mode for Computer Hard Disks

Abstract

In recent years, auto-sleep functions for hard disk drives of computer systems have been paid much attention in term of the power saving. In this paper, we suggest the optimal design for sleep mode under the performance criterion called power effectiveness. In particular, we consider the situation where access requirements are accumulated in the buffer of a system. When the access requirements occur in accordance with the homogeneous Poisson process, the optimal sleep time which maximizes the power effectiveness is analytically derived. For more general cases, two kinds of approximate methods are proposed.