``SmartSaver: turning flash drive into a disk energy saver for mobile

Feng Chen, Song Jiang, and Xiaodong Zhang

Proceedings of the 11th International Symposium on Low Power
Electronics and Design (ISLPED'06), Tegernsee, Germany, October 4-6,


In a mobile computer the hard disk consumes considerable amount of
energy. Exist ing disk dynamic power management policies usually take
conservative approaches to save energy, and dis k energy consumption
remains a serious issue. Recently the flash drive is becoming a
must-have portab le storage device for almost every laptop user on
travel.  In this paper, we propose to make another highly desired use
of the flash drive --- saving disk energy.  This is achieved by using
unused space in the flash drive as a standby buffer fo r caching and
prefetching disk data. Our design can significantly extend disk idle
time wi th careful and deliberate consideration of unique
characteristics of the flash drive. The trace-driven sim ulation shows
that the disk energy can be saved up to 42% with a relatively small
amount of data w ritten to flash drive.