Research And Application Of The UBI File System Based On Nand Flash On The Android Platform

With the rapid development of embedded file system technology, the current mainstream file system can not meet the project requirements in function and performance aspects.Based on the analysis of UBI (Unsorted Block Image) file system's functionality requirements, performance requirements, and structure design, the article attempts to build UBI file system on the embedded system project board (CPU chip is the i.MX51 from freescale) and design four modules and gives the designing and implementing ways of these four modules which are u-boot bootloader module, bad block management module, the system recovery function module and DDR memory parameter module. To achieve this, firstly as for the u-boot bootloader module the author develops a good mechanism of MTD (Memory Technology Device) partitions and passing parameters of UBI file system to ensure the correctness of the system boot. Then in bad block management module aspect, the problem of factory bad block management can be solved by designing a bad block table management strategy. Once more, the article gives an automatic identification method to achieve the factory reset, and adds an enforcement system install function in the system recovery function module. Finally, selecting one of multiple sets of parameters on the basis of test results is to achieve the stability and high-efficiency of system working.The final experimental data show that the function and performance targets of the UBI file system achieve to design requirements.