导　　师： 周功业

学科专业： 081201

授予学位： 硕士

作　　者： ;

机构地区： 华中科技大学

摘　　要： 由于采用闪存芯片作为存储介质,固态硬盘继承了NAND Flash闪存存储器独特的硬件特性。闪存芯片读//写/(编程/)操作以页为基本单位,擦除以块为基本单位,通常块由若干页组成,按页写入时,必须先擦除再写入,还有对同一数据块的擦除次数是有限的,超出规定的擦除次数某些块就会提前损坏。Flash存储器的这些硬件特性严重影响了固态硬盘的写入速度、寿命和可靠性等主要性能。 固态硬盘的闪存损耗均衡一直是固态硬盘研究的热点问题。根据闪存的块擦除方式确定了闪存损耗均衡的性能指标,在此基础上从动态损耗均衡策略和静态损耗均衡策略两方面对闪存损耗均衡进行了系统分析和设计。给出的固态硬盘闪存损耗均衡策略兼顾动态损耗均衡和静态损耗均衡,采用最小擦除次数块分配策略、垃圾回收策略及静态损耗均衡策略使闪存所有物理块的擦除次数趋向一致。 另外,针对闪存的存储特性实现了固态硬盘的存储管理层。固态硬盘的存储管理层可以向上层系统屏蔽闪存的内部特性,实现损耗均衡策略以及标准块设备的访问接口。在分析固态硬盘存储管理层体系结构的基础上,从地址映射机制、坏块管理与数据存储安全、快速启动与掉电恢复等多方面对固态硬盘的存储管理层实现技术进行了论述。 仿真实验结果表明,该策略能够使闪存中的全部块擦除次数均匀化,进而显著提高固态硬盘的使用寿命。 As a result of Nand flash memory being widely used as the storage medium, solid-state disk has inherited the unique hardware features from the Nand flash memory. Unlike standard block devices, ?ash memory media need to be erased before program operations. An erase operation is performed in a unit of a block which is composed of 32–128 pages, while read//program operations are executed in a unit of a page. Unfortunately, the number of block erasure cycles is limited, and the data stored in the block beyond this limit will be unreliable. The hardware characteristics of flash memory have a serious impact on solid-state disk writting speed, longevity and reliability of other major performance. The wear-leveling algorithm of flash memory is a hot issue of research in designing solid-state disk. According to the way of flash memory block erase operation identified the wear-leveling performance indicators, on the basis of a dynamic wear-leveling and static wear-leveling strategy the flash wear-leveling algorithm is analyzed and designed. A solid-state disk wear-leveling algorithm considering both dynamic and static wear-leveling uses the smallest number of erase block allocation strategy, the garbage collection strategy and a static wear-leveling approach which will make all the blocks of flash in the average number of erasure cycles. In addition, on the basis of the characteristics of flash memory the solid-state disk storage management system is implemented. Solid-state disk storage management system can shield characteristics of flash memory to the top user over SSD, and achieve wear-leveling algorithm, as well as the standard block device interface. Based on the architecture analysis of solid-state disk storage management system, the address mapping mechanism, bad block management and data storage security, quick start and power off recovery scheme, and etc are discussed in detail. The simulation results of wear-leveling of solid-state disk show that the strategy can make all the blocks in the fl

关 键 词： 固态硬盘 闪存 损耗均衡 存储管理

领　　域： [自动化与计算机技术] [自动化与计算机技术]