Method for building file systems on NAND flash memory in embedded system

Abstract

The invention discloses a method to establish a file system in NAND Flash storage in an embedded system. The invention is a single-leveled directory file system that utilizes a page interlinking page to manage storage space; a file registration list and a file allocation table of the system are stored in a float address mode; variation of FRT and FAT in the RAM memory will be written into a Flash storage in a real-time on-line increment mode for an increment file registration list and an increment file allocation table; in the single-leveled directory file system, relevant information of the file registration list and the file allocation table is simultaneously written into redundancy bits in relevant block pages in the Flash data area, so as to provide backup for the single-leveled directory file system. The invention improves FRT and FAT with fixed storage addresses into movable storage addresses, in order to establish a wearing balancing mechanism; in Delta FRT and Delta FAT of a Flash storage, the invention can fulfill real-time record for FRT and FAT variations in RAM memory, so as to provide a file system failure recovery mechanism; besides, the invention utilizes redundancy bits of each page in a Flash storage to write relevant information for the file system, in order to establish a redundancy backup mechanism.

Description

technical field [0001] The invention relates to the technical field of Flash memory, in particular to a method for establishing a file system on a NAND Flash memory in an embedded system. Background technique [0002] Embedded systems use rewritable non-volatile Flash memory to store code and data. The file system shields the technical details of the physical memory, and organizes the managed information into files, thereby increasing the portability and maintainability of the program, which is convenient for users to effectively manage a large amount of data. Therefore, it is common to establish a file system on the Flash memory. actual meaning. At present, there are many mature file systems on general-purpose computers, such as the FAT file system under Dos, the NTFS file system under Windows NT, and the Unix and Linux file systems, but the above file systems are not suitable for direct use in embedded systems. The problems are as follows: firstly, the application enviro...

AI Technical Summary

Problems solved by technology

At present, there are many mature file systems on general-purpose computers, such as the FAT file system under Dos, the NTFS file system under Windows NT, and the Unix and Linux file systems, but the above file systems are not suitable for direct use in embedded systems. The problems are as follows: firstly, the application environment of embedded systems is far worse than that of computers, and the design of general-purpose file systems has insufficient consideration for reliability; secondly, general-purpose file systems are based on resource-rich computer platforms and slow disk drives, and often use caches that consume a lot of resources. And other technologies, which are completely different from the situation of limited resources in embedded systems; the third point comes from the inherent characteristics of NAND Flash, NAND Flash memory is composed of several blocks, a block is composed of several pages, and a page contains a certain number of bytes storage unit and several redundant bytes

[0003] At present, there are three types of file systems on the large-capacity Flash memory: JFFS2, YAFFS and TyueFFs. These three file systems based on the log structure need to occupy more resources.

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