Exploiting flash memory for reducing disk power consumption in portable media players

Portable media players are increasingly using hard disk drives (HDD) to meet their storage requirements, but HDDs consume a significant amount of energy. Therefore video frames are prefetched into dynamic random access memory (DRAM) to allow the disk to go into low-power mode; but most mobile systems have limited DRAM, so little energy is actually saved in this way. We propose two new energy saving schemes: one improves the utilization of DRAM in storing prefetched frames, and the other extends this approach by making use of auxiliary flash memory. Simulations show that deploying a reasonable amount of auxiliary flash reduces disk energy consumption by up to 86% compared with conventional prefetching schemes.