A Study Management and Fast Model Base on NAND Type Flash

• Main Authors: Chun-Ta, Chen, 陳俊達
• Other Authors: Wen-Tzeng Huang
• Format: Others
• Language: en_US
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/07560666300089113984

碩士 === 國立臺北科技大學 === 電腦通訊與控制研究所 === 92 === The NAND type flash memory, briefly denoted by NandFlash, is one of the major applications in the embedded computing system, for its advantages of small size, great capacity, light power consummation, not volatility, and enduring vibration. For the special characteristic of the semi-conductor in NandFlash, its applications will be limited and its manager method will also be complication. It is a major study topic to effectually manage this NandFlash. Especially, when a file system manages the huge size NandFlash, the performance of management mechanism will be more importance. To aim at NandFlash as the main research topic in this thesis, we not only propose a completely effective management mechanism but also implement a fast model NandFlash in the system. We discuss this NandFlash management mechanism first. In our proposal of the management system, since the basic erasing unit is a block in NandFlash, we use a block as the study basis with the meaning. In our NandFlash management mechanism, to reduce the cost of the erasing frequency, to extend its life cycle, and to promotes the system performance are major purposes. By dynamically analyzing the state of the data attribution, the data is divided into cold or hot data attribution and then re-written into the different block for reducing the nonsensical actions. Further, we can reduce the cost and promote the performance of the system. Then, we adopt a dynamic cycle-leveling strategy to extend the life cycle of NandFlash. It only needs to sacrifice a jot cost for extending the life of flash memory and promoting the high usage. The performance will be more explicit with the allocation strategy index and the cycle-leveling strategy of our proposal model. Furthermore, we implement the fast type model of NandFlash, said FNandFlash. According to the characteristic of the flash memory, NOR type flash memory, denoted by NorFlash, and NandFlash are generally in Embedded System used. Moreover, for the major factors, the unit cost, access speed, physical volume, and capacity size, of a flash memory to utilization, we implement a FNandFlash, which is based on the NorFlash issues. The implementation method is to combine a FPGA with NandFlash into a FNandFlash, whose cost is cheaper and random access speed is lower than that of NorFlash. Making the access speed of FNandFlash is about 90% of NorFlash. The major function behavior of FNandFlash can simulate the application of most NorFlash.