Research And Realization Of Embedded File System Based On μC/OS II

With the application of embedded system steady deepening and the industrialization degree constantly upgrading, the new application environment and industrialization demand made strict requirement on embedded software. Spurred on by the new requirement, whether embedded software is high-performance, strong real-time character, open source code, cheap and perfect function became the crucial factor of selecting operating system. The embedded operating systemμC/OS-II has the above advantages, so it has been applied widely. ButμC/OS-II is just a real-time kernel, and it doesn't have many other functions, such as system clock management function, file management function, human-computer interaction function, graphics user interface (GUI) function and so on. In order to achieve a relatively comprehensive and practical embedded real-time multi-task operating system, its function should be expanded according to the application requirements. However, because the restraint of the hardware resource of embedded products, running environment and application requirement, the file management system usually require handtailor. This paper expanded the file system functions ofμC/OS-II on the base of its good expanded ability, designed and realized a relatively reliable, efficient, flexible file management module. This expansion can be abundant and initiated the function of the embedded operating system; strengthened data management ability of the embedded system greatly, can also provide support and promote function when to developing other application software at the same time, and has high practical significance.First, this paper analyzed the application requirements of embedded system, and discussed the necessity of introducing file management function. Second, this paper contrast the characteristics, the performances, and use field of employment of the general desktop file system and the current mainstream embedded file system, then got the design goals of embedded file system. Third, this paper focused on the realizing technology of the embedded file system, and expounded the organization method, system structure and the way of realizing of the general embedded file system. Lastly, on the platform of S3C2410 andμC/OS-II, this paper refers to the Minix file system, then designed and realized a file management module which has create, delete, read /write, manage file and directory etc functions and establishing it on NAND FLASH.This file management module is an independent self-contained entity based on theμC/OS-II task. It adopted a clear layering structure, making each layer realized relatively independently, and it has realized the management function of file and directory through file system API interface which according with POSIX standard, so that this file management module can be ported and improved conveniently. It also has used a device driver table to choose the driver automatically, then made the file system have nothing to do with the equipment, thus can be applied on different system resources. It also used block high-speed cache to reduce the number of visiting storage media, thus impoved the efficiency of the file system. The application on the intelligent ammeter, the steam turbine protective meter has shown this file system meet the multi-task and real-time requirements of the embedded system, and has common character and spread value.