I/O Performance Optimization Techniques for Hybrid Hard Disk-Based Mobile Consumer Devices

A hybrid hard disk employs the advantages of both a hard disk and a NAND flash memory, thus making it a cost-effective fast secondary storage device. In this paper, we improve its I/O performance by combining an intelligent data pinning policy for the flash memory with a caching technique which is aware of access patterns for the flash memory and DRAM. Our proposed techniques reduce the system boot time and application launching time while reducing energy consumption, which is vital in the mobile devices. We built SimHybrid, a flexible trace-driven hybrid hard disk evaluation environment, and used it to demonstrate how a hybrid hard disk can achieve significantly better I/O performance than a traditional hard disk while using much less energy.