固态盘的闪存转换层设计与优化

发布时间：2018-04-17 22:24

本文选题：固态盘 + 闪存　；参考：《华中科技大学》2013年硕士论文

【摘要】：固态盘(Solid State Disk,SSD)作为大容量存储介质具有读写速度快、功耗低、防震抗摔等优点，其性能主要由闪存芯片、主控芯片以及固件程序决定。其中主控芯片的接口速度是提高固态盘性能的主要因素之一；固件程序中的闪存转换层(Flash Translation Layer,FTL)将闪存模拟成与磁盘类似的块设备，屏蔽闪存的特性，更好地向上兼容文件系统。选用Xilinx高性能FPGA作为固态盘的主控芯片，移植微处理器MicroBlaze，通过片内总线AXI连接各功能模块，搭建固态盘控制器SOPC系统架构。以固态盘SOPC系统为硬件平台，设计实现了闪存转换层。闪存转换层提供初始化、命令解析地址映射、缓冲区管理、垃圾回收以及坏块管理功能：通过命令解析和地址映射，将文件系统发送的命令传递给闪存控制单元；通过引入缓冲区管理，降低直接读写闪存的开销；通过垃圾回收和坏块管理对闪存芯片的使用空间进行控制和管理。经过测试，验证了闪存转换层的基本功能。闪存转换层的性能直接影响固态盘的性能，为了提高固态盘的效率，针对闪存转换层的缓冲区管理提出并实现了改进的LRU算法：即在LRU算法基础上，，利用数据的冷热属性和更新属性选取替换块。通过在固态盘模拟器SSDsim上运行真实的数据负载，验证算法在命中率、擦除次数以及平均响应时间等方面的性能，相比LRU算法和CFLRU算法都有所提升。
[Abstract]:Solid State disk SSD) as a large capacity storage medium has the advantages of fast reading and writing speed, low power consumption, anti-shock and anti-fall, etc. Its performance is mainly determined by flash memory chip, master control chip and firmware program.The interface speed of the main control chip is one of the main factors to improve the performance of the solid-state disk, and the flash memory conversion layer in the firmware, Flash Translation layer, simulates the flash memory as a block device similar to the disk, shields the characteristics of the flash memory, and is better compatible with the file system up.The Xilinx high performance FPGA is selected as the main control chip of the solid-state disk, the microprocessor MicroBlazeis is transplanted, and each function module is connected through the on-chip bus AXI, and the SOPC system architecture of the solid-state disk controller is built.Using solid state disk SOPC system as hardware platform, flash memory conversion layer is designed and implemented.Flash translation layer provides initialization, command parsing address mapping, buffer management, garbage collection and bad block management functions: through command resolution and address mapping, the file system sent commands to flash control unit;The overhead of direct reading and writing flash memory is reduced by introducing buffer management, and the usage space of flash memory is controlled and managed by garbage collection and bad block management.After testing, the basic function of the flash memory conversion layer is verified.The performance of flash transfer layer directly affects the performance of solid-state disk. In order to improve the efficiency of solid-state disk, an improved LRU algorithm is proposed and implemented for buffer management of flash conversion layer, that is, based on LRU algorithm.Select the replacement block using the hot and cold attributes of the data and the update properties.By running the real data load on the solid state disk simulator SSDsim, the performance of the algorithm in hit ratio, erasure times and average response time is verified. Compared with the LRU algorithm and CFLRU algorithm, the performance of the algorithm is improved.
【学位授予单位】：华中科技大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TP333

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