Flash Storage Applications and Challenges

The Solid State Disk (SSD) implemented using NAND flash memory significantly outperforms conventional rotating magnetic disk drive in read performance. However, write performance of flash based SSDs can be up to an order of magnitude slower than its read performance. This fundamental disparity is caused by the fact that flash write operations are immutable and a data sector must be erased before it is rewritten. Furthermore, frequent write operations degrade the lifetime of flash memory over time. In this thesis, various techniques have been proposed to improve write performance of flash memory as well as flash-aware algorithms are designed to avoid frequent update operations.