NAND Flash存储管理的设计与实现
发布时间：2018-08-12 19:56
【摘要】：在信息技术飞速发展的今天,数字产品也日益普及,数据的存储与管理已成为人们关注的焦点。NAND Flash由于其价格低、体积小、存储量大等实用性特点成为嵌入式数据存储的主要介质。考虑NAND Flash的硬件特性,有必要对其进行数据存储管理。NAND Flash存储管理的主要方法有两种：一种是通过闪存转换层将NAND Flash模拟成磁盘设备,采用通用文件系统进行管理；另一种是采用专门为NAND Flash设计的文件系统对其进行管理。考虑到以NAND Flash为存储设备的嵌入式系统一般都需要与计算机进行数据通信,采用第一种方法对NAND Flash进行存储管理设计可以保证与通用桌面系统的兼容性。 本文的设计针对广泛应用的NAND Flash存储器,设计并实现闪存转换层将NAND Flash模拟成块设备,采用FAT文件系统对存储数据进行管理。论文分析了FAT文件系统的规范和实现形式,深入理解了NAND Flash存储管理技术,包括地址映射、坏块管理、磨损均衡、掉电保护,并重点对NAND Flash存储管理的关键技术的实现进行了分层介绍。 论文的具体工作包括以下几个方面：(1)设计了适用于大容量NAND Flash的地址映射机制。采用了两种方式对地址映射表进行存储,即使在突然掉电的情况下,也能对地址映射表快速恢复,提高了存储的可靠性。(2)对NAND Flash在出厂时和使用过程中产生的坏块进行分别处理。出厂时的坏块在NAND Flash初始化时进行标记并屏蔽。使用过程中的坏块,采用动态坏块管理方式,对NAND Flash使用过程中遇到的擦写失败的块进行替换。(3)针对NAND Flash擦除次数有限的物理特性,将NAND Flash中每个物理块的擦除情况都记录在一个磨损均衡表中,根据这些信息实现块的均匀擦写。由于嵌入式设备的内存有限,故本文设计了低内存消耗的磨损均衡机策略,尽可能保证各个物理块的擦写次数相近,延长了NAND Flash的使用寿命。(4)采用USB通信协议实现了NAND Flash设备和主机的通信,并在主机上对系统的功能和性能进行测试。
[Abstract]:With the rapid development of information technology, digital products are becoming more and more popular. The storage and management of data has become the focus of attention. NAND Flash is small because of its low price. Large storage capacity and other practical characteristics of embedded data storage become the main medium. Considering the hardware characteristics of NAND Flash, there are two main methods of data storage management. NAND Flash storage management. One is to simulate NAND Flash into disk device by flash transfer layer and manage it by general file system. The other is to use a file system specifically designed for NAND Flash to manage it. Considering that the embedded system with NAND Flash as the storage device generally needs to communicate with the computer, the design of storage management for NAND Flash by the first method can guarantee the compatibility with the general desktop system. The design of this paper aims at the widely used NAND Flash memory, designs and realizes the flash memory conversion layer simulates the NAND Flash into the block device, uses the FAT file system to manage the storage data. In this paper, the specification and implementation of FAT file system are analyzed, and the storage management technology of NAND Flash is deeply understood, including address mapping, bad block management, wear balance, power failure protection, etc. The key technologies of NAND Flash storage management are introduced in detail. The main contents of this paper are as follows: (1) address mapping mechanism for large capacity NAND Flash is designed. The address mapping table is stored in two ways. Even in the case of sudden power failure, the address mapping table can be restored quickly. The reliability of storage is improved. (2) the bad blocks produced by NAND Flash are treated separately. Factory bad blocks are marked and shielded during NAND Flash initialization. In the process of using the bad block, the dynamic bad block management method is used to replace the block that the erasure failure encountered during the use of NAND Flash. (3) aiming at the physical characteristic of the limited number of NAND Flash erasures, The erasure of each physical block in NAND Flash is recorded in a wear equalization table, according to which the block is uniformly erased. Because of the limited memory of embedded devices, this paper designs a wear equalizer strategy of low memory consumption, which ensures that the number of erasures of each physical block is close as much as possible. The service life of NAND Flash is prolonged. (4) USB communication protocol is used to realize the communication between NAND Flash device and host, and the function and performance of the system are tested on the host computer.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP333
本文编号：2180193
[Abstract]:With the rapid development of information technology, digital products are becoming more and more popular. The storage and management of data has become the focus of attention. NAND Flash is small because of its low price. Large storage capacity and other practical characteristics of embedded data storage become the main medium. Considering the hardware characteristics of NAND Flash, there are two main methods of data storage management. NAND Flash storage management. One is to simulate NAND Flash into disk device by flash transfer layer and manage it by general file system. The other is to use a file system specifically designed for NAND Flash to manage it. Considering that the embedded system with NAND Flash as the storage device generally needs to communicate with the computer, the design of storage management for NAND Flash by the first method can guarantee the compatibility with the general desktop system. The design of this paper aims at the widely used NAND Flash memory, designs and realizes the flash memory conversion layer simulates the NAND Flash into the block device, uses the FAT file system to manage the storage data. In this paper, the specification and implementation of FAT file system are analyzed, and the storage management technology of NAND Flash is deeply understood, including address mapping, bad block management, wear balance, power failure protection, etc. The key technologies of NAND Flash storage management are introduced in detail. The main contents of this paper are as follows: (1) address mapping mechanism for large capacity NAND Flash is designed. The address mapping table is stored in two ways. Even in the case of sudden power failure, the address mapping table can be restored quickly. The reliability of storage is improved. (2) the bad blocks produced by NAND Flash are treated separately. Factory bad blocks are marked and shielded during NAND Flash initialization. In the process of using the bad block, the dynamic bad block management method is used to replace the block that the erasure failure encountered during the use of NAND Flash. (3) aiming at the physical characteristic of the limited number of NAND Flash erasures, The erasure of each physical block in NAND Flash is recorded in a wear equalization table, according to which the block is uniformly erased. Because of the limited memory of embedded devices, this paper designs a wear equalizer strategy of low memory consumption, which ensures that the number of erasures of each physical block is close as much as possible. The service life of NAND Flash is prolonged. (4) USB communication protocol is used to realize the communication between NAND Flash device and host, and the function and performance of the system are tested on the host computer.
【学位授予单位】：广东工业大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TP333
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