Research On Flash Transition Layer With Safe File System On Embedded OS

With the development of the national economy,people's attention to the security and integrity of data storage requirements is increasing day by day.Traditional functional safety file systems such as JFFS are mostly based on Linux systems,which are not considered traversal for most people.The native FAT file system has a high penetration rate and good compatibility but cannot ensure data security in unexpected situations such as power failure.Therefore,this analysis proposes Safe FAT,a FAT-type functional safety file system based on the Reworks high security embedded operating system,based on the idea of the log file system.After more than 20 rigorous test cases,Safe FAT has shown good robustness.It can be said that the demand is basically solved.However,only considering the upper file system without caring about the structure of the bottom storage is incomplete for the design of the entire operating system.As the storage medium,the memory semiconductor in the form of Flash does not need to rely on the traditional Winchester mechanism and does not need to seek,which greatly reduces the access delay of input and output requests,and at the same time it is replaced by the advantages of low power consumption,shock resistance,drop resistance,and small size.The FTL algorithm is one of the key technologies in the flash memory system,which will directly have a significant impact on the read and write performance of the solid state disk,and therefore affect the performance of the entire operating system.The article first introduces the basic working principle and physical structure of flash memory,and analyzes the current shortcomings of address mapping,garbage collection,wear leveling,and bad block management in FTL.The focus is on garbage collection and garbage collection based on the dual pool algorithm.In the final simulation and testing analysis,the idea of layer-by-layer testing is used.First,the various FTL algorithms at the bottom layer are individually tested in the Flashsim simulation software with three real trace load data files from the average system response time,the number of block erases,The additional read and write times generated by garbage collection and wear leveling were tested in three aspects,and the results obtained were compared and analyzed,showing that the algorithm based on search trees has improved performance.Secondly,test cases were written and tested for the 23 functional points of Safe FAT.The test results showed that Safe FAT meets the requirements of a functionally safe file system,with stable performance and almost the same read and write speed as the native FAT file system.