Research And Design For Filesystem Used In Embedded Environment

With the development of embeded computer technology, cost of outside storage devices is decreased gradually, comparatively the data count which embeded application required is increased day by day. How to administer those devices and data effectively becomes an important problem of embeded system development. As a component of embeded realtime control system, the embeded file system offers the specific function of data storage and outside devices administration.Characters of embeded system caused relatively obvious differance between embeded file system and usual desk file system. Firstly, the limitation of embeded system's physical storage decides that embeded file system must has its code tight, and couldn't cause any code cost to system when no file system is being used. Secondly, embeded file system should be separated with hardware system structure as possible as it could, thus it should contain good ability of replanting when being realized. Thirdly, file system is a component of embeded system, which is offered to users as a selection and decided by users whether to load or not.The project based on Chemical Irradiance Detecting System, so take requirement of Chemical Irradiance Detecting System into considerration, we design a file system based on FAT format, architecture of the file system contains three parts form bottom to top : manage layer for drivers, file system kernel layer and application interface layer. This architecture satisfied the demands of Chemical Irradiance Detecting System, such as compact code, support sevrel storrige devise and good ability of replanting. Besides, this file system offers smart application layer API interface and devices drivers administration interface, in order to make Chemical Irradiance Detecting System update and expandsion in future easy.This paper does researchs about usual embeded outside devices and technology of file system, then offers a system structure of embeded file system based on FAT format, describes design plans and concrete realization of each submodules in detail, and designs drivers of usual outside devices which used by embeded file system. At last, this paper makes some conclusions about achievements and shortages of this project, and gives a preview of the development trend of embeded file system.