Modeling Hard-Disk Power Consumption

Excessive power consumption is a major barrier to the market acceptance of hard disks in mobile electronic devices. Studying and reducing power consumption, however, often involves running timeintensive disk traces on real hardware with specialized power-monitoring equipment. This paper presents Dempsey, a disk simulation environment that includes accurate modeling of disk power consumption. It includes tools to automatically extract performance and power consumption parameters from a given disk drive, without needing detailed specifications from the manufacturer. The tools use stimulus-based measurements to extract these parameters. Dempsey is experimentally validated for two mobile hard disks, namely, the 1 GB IBM Microdrive and the 5 GB Toshiba Type II PC Card HDD. In the worst observed case, Dempsey’s estimate of power consumption differs from the measured consumption by 7.5%. This demonstrates that disk power consumption can be simulated both efficiently and accurately.