A Compressed Page Management Scheme for NAND-type Flash Memory

Abstract

Compressed data management in NAND-type flash memory is difficult because it only supports page I/O. For example, when the size of compressed data is smaller than page size, internal fragmentation occurs, and this degrades the effectiveness of compression seriously. To reduce internal fragmentation, the compression unit should be sufficiently large. However, larger compression unit induces longer read and write latencies for random accessing. We, therefore, present a novel compressed page management scheme that stores several small compressed pages to one physical page by using a write buffer. Simulation results show that our proposed scheme can significantly expand storage capacity without having to delay read and write latencies.