Research And Implement Of Nand Flash Memory Management Based On Security U-Disk

With the development of information technology and usage of digital products, nowadays embedded system has become hot spot in computer technology research and application field. Managing the huge amounts of data is the key research point in embedded system. NAND flash is increasingly becoming the new darling of the embedded data storage with the advantages of low price, huge storage capacity and small size. This paper designs and implements an efficient memory management of security U-disk in the base of large research on NAND flash and file system. The memory management which is implemented in the paper is in view of the current memory management that is in lack of consideration for NAND Flash with large capacity.Firstly, the paper researchs the physical features of NAND flash and its specification. And many file systems which are very prevalent nowadays, are researched here. The author analyzed the current U-disk market demand, then hardware and software frame as whole are designed in this paper, according to performance and function.In this paper, the innovative work reflects in the following seveal aspects: 1. Research and implement a unique way of status description which satisfies to MLC NAND flash. 2. Research and implement block map and zone map which make memory managemet suitable for any capacity of NAND flash. 3. Research and implement super stability technology which prevents the complete collapse of the file system int situation of unexpected power outage. 4. Research and implement continuous write and discontinuous write to improve the performance of writing. 5. Research and implement shadow write which makes parallel execution of discontinuous write possible. Because the time which is spent in writing FAT is reduced, progress bar will be shown in short time when copying files. 6. Research and implement dynamic bad block management mechanism is introduced to improve the stability of U-disk. 7. Research and implement wear-leveling to extend the life of U-disk.