New Embedded Mobile Memory Card Standard Research And Implementation

Recently, with the development of Internet and computer, the embedded systems are becoming the center of interest in the IT industry and exhibiting their broad potential market. Meanwhile, the handheld devices are more and more popular and its applications are calling for the better performance and functionality of embedded systems. More and more media applications are used in embedded devices,also appearing diferent types of store mediator example ,NAND Flash and NOR Flash. Even hough,different store devices,Multiple Media Card,Compact Flash,U disk,which are based on the same media,NAND Flash,appeared.It is not easy to solve the problem of manage files on the different store devices which are used in the operating system not supported by file system. Also how to make the memory card standards compatible in size become a topic of concern.File system is one of the most primary sources in operating system, which is a collection of files and directories in computer system. With the increasing of availability and lowering of embedded system hardware's price, and the expanding of application fields, the embedded systems play a more important role and the development of embedded file system attracts more attention. Embedded systems are usually diskless systems. In order to keep permanent data in the systems, it is a widely adapted strategy to use flash memory disk as its disk system, therefore how to build a flash memory file system is the focus of this thesis in a reasonable embedded system.In my research field, I completed a FAT file system named FFS which is used for managing files on the NAND Flash media, this FAT file system is on the base of MS-DOS standard. FFS supports FAT16 and FAT32, and it can satisfy all the standard file I/O requests with enough application interfaces, including reading file, writing file and deleting file, which are for application use. It also support managing bad clusters on NAND Flash automatically, and this function interface is transparent to users. After practice of using FFS file system on cell phone system, users of FFS got a conclusion that this file system can satisfy all the requests from applications, and it is well fit for cell phone system.The subject also designs the mechanical appearance of a new generation of mobile memory card, its volume is the same with the standard SD/MMC memory card, but it has greater efficiency and capacity than the standard SD/MMC memory card, and it is fully compatible with the standard SD/MMC card.