Design And Implementation Of Embedded NAND Flash Storage System

With the development of information technology and wide usage of digital products, nowadays embedded system becomes a hotspot in computer technology area. NAND Flash memory is a non-volatile solid state memory and is widely used in many embedded systems because of its low power consumption, fast I/O, large capacity, low cost, shock resistance property and etc. There are two kind of methodology applied to management of Flash storage. The first one is using FTL (Flash Translation Layer) to simulate it as a traditional R/W block device and apply a traditional block file system to manage it. The other is to manage it using specialized file systems. In this paper, an embedded Linux NAND Flash storage system using FTL for mobile internet device is designed and implemented. It includes block layer, FTL layer and LLD layer.This paper first introduces the background and current status of embedded system. The background and value of NAND Flash storage system development project are also be referred. Then, this paper focuses on the Flash technology and Flash memory devices. NOR Flash and NAND Flash are compared in this paper. The usage of NAND Flash is introduced with an emphasis. The last part of this chapter introduces the NAND Flash chips we used. Next, this paper demonstrated about how to design and implement NAND Flash storage system hierarchically,, and emphasized on redesign of block interface layer, optimization of cache replacement algorithm, method of address mapping table storing and wear leveling algorithm we used. At last, the paper summarized about the development of the system and gave an expectation of future developing of the system, including hardware improvement and embedded USB host system's integration to video phone system task.