Design and Implementation for Multi-level Cell Flash Memory Storage Systems

Abstract

NAND flash memory has gained its popularity in a variety of applications as a storage medium due to its low power consumption, non-volatility, high performance, physical stability, and portability. In particular, Multi-Level Cell (MLC) flash memory, which provides a lower cost and higher density solution, has occupied the largest part of NAND flash-memory market share. However, MLC flash memory also introduces new challenges: (1) Pages in a block must be written sequentially. (2) Information to indicate a page being obsoleted cannot be recorded in its spare area. This paper designs an MLC Flash Translation Layer (MFTL) for flash-memory storage systems which takes new constraints of MLC flash memory and access behaviors of file system into consideration. A series of trace-driven simulations is conducted to evaluate the performance of the proposed scheme. Our experiment results show that the proposed MFTL outperforms other related works in terms of the number of extra page writes, the number of total block erasures, and the memory requirement for the management.