Research On File System Based On Embedded Platform

File system is a way of organizing files on a storage device, which is a kind of storage mechanism based on file and directory. File system is accomplished to store data in files on external memory devices, so a large amount of data can be stored and exchanged in embedded system.In this paper the characteristics and functions of file system in embedded system are researched, and the software is designed to complete the embedded file system based on the FAT file format. In order to further validate the stability and reliability of the file system, data recovery is realized. The research focus on detailed design and implementation of embedded FAT file system and data recovery.Main contents of the research consist of two aspects:one is the design of embedded FAT file system. The modular architecture technology is used to design and analyze hierarchical structure based on the characteristics of embedded file system; The other one is to research loss condition of data in FAT file system, according to the storage structure and mechanism of FAT file system, the method to recover data is designed and completed. The structure of FAT file system is divided into:device driver layer, file system core layer and user interface layer. Device driver layer completes the operations of reading and writing SD card sector. The specific management and control functions of storage media is shield for the upper layer. The functions provided by Device driver layer is the basis of the realization of the file system; The core layer of the file system converts the abstract operation of the file to the sector operation, which implements the logical operation of the file and directory, and the management of the storage space; User interface layer provides interface function to accomplish operation of file and directory in order to provide users with simple and convenient operation of file. The functions of file system are tested by building a set of ARM7 hardware platform in the environment of Keil software. The function of the embedded file system and the method of data recovery are tested to demonstrate the effectiveness and stability of the system.The research is part of the key project of National Science Foundation of China-"New theory and key technology of ship wireless autonomous orientation method based on AIS" NO.61231006. The research meets the requirements of portable data storage in embedded AIS receiver.