【作者】 唐卫明；

【导师】 刘衡竹；

【作者基本信息】 国防科学技术大学 ， 计算机科学与技术， 2009， 硕士

【摘要】 数据存储设备是航天器的关键设备之一,为多种空间试验及探测设备的数据采集、存储以及在轨处理提供了重要的支撑平台。随着航天电子技术的发展,以闪存(Flash Memory)为基本存储介质的大容量固态存储器已经成为当前航天器数据存储的主流方案之一,因此建立一个大容量、高效率的闪存存储管理机制尤为重要。然而与此同时,针对闪存设备设计的存储管理机制相对落后,现有FlashMemory存储管理机制大多基于上个世纪九十年代和本世纪初的设计,无法满足NAND Flash存储容量飞速增长的要求。本文在“航天器嵌入式安全操作系统研究”基础软件研究项目和“921二期VxWorks源代码分析”研究项目的工作基础上,深入探讨了大容量NAND闪存的存储管理机制及其实现。本文首先分析了NAND闪存的特点和NAND闪存的存储管理现状；再在源代码级别上深入研究了Linux MTD和VxWorks TrueFFS两种存储管理方案的原理及其实现；以此为基础提出了一种新的NAND Flash存储管理方案VNFS。VNFS基于传统UNIX文件系统思想设计,针对NAND Flash的存储特性进行了改进。一是针对文件系统中访问频繁的文件系统关键数据进行冗余存储,建立了浮动的超级块及根目录；二是使用索引节点文件存储文件的索引节点,在存储介质上建立了动态的索引节点树；三是针对Flash存储介质的写入重定位特性采用了漫游树算法。VNFS大幅度的缩短了文件挂载时间,降低了内存消耗,能够满足大容量NAND Flash的管理需要。更多还原

【Abstract】 Device for data storage is one of the key equipments in the spacecrafts.It provides an important platform to save data for a lot of kinds of space experiments and detection devices.With the development of the spaceflight technology, the large-capacity solid-state storage system based on flash memeory is needed,and the storage management mechanism supporting large capacity and high efficiency is particularly important. The flash memory capacity is growing rapidly in the last few years,and the applications are more and more multiplex. In the other hand,the current designs of storage management mechanism for flash memory is still lagging behind, they are designed in the nineties of last century and the beginning of this century,and can not meet the rapid increasement of the NAND flash memory.Based on the work of two projects"secure embedded operating system for spacecraft" and "921 second phase source code analysis of vxWorks",this thesis deeply researched implementation of the management mechanism of large-capacity NAND flash memory.In this thesis,firstly researched the characteristic and the storage management technology status of NAND flash memory;and then deeply analysed two flash memory storage management architechture Linux MTD and VxWorks TrueFFS on source code level.Based on it,this thesis puts forwards a new NAND flash memory management system VNFS.VNFS is designed based on traditional UNIX filesystem ideology,and aimed at the storage characteristics of NAND Flash.Firstly,it uses drifting super-block; secondly,it uses dynamic tree of index node; thirdly,for the write out of place specialty of flash memory, it uses wandering tree algorithm.VNFS has shorter file system mounting time and less memory consumption, so it can meet the demand for large-capacity flah memory management needs.更多还原