面向Flash存储器的FAT文件系统可靠性增强机制

FAT文件系统针对Flash存储器使用时,其FAT表存储位置不确定且各个簇之间的擦写次数不均衡,导致其可靠性降低.针对上述问题,提出了两种解决方案,分别是FAT表可控迁移和空闲簇磨损均衡.前者在Flash上预留多个块存储FAT表,每次更新FAT表时在其中选择擦除次数最小的块,预留一个块记录最新FAT表的入口地址;后者在Flash上预留一个块记录FAT表中各个簇的擦写次数,每次分配空间时选择擦写次数小于擦除阈值的空闲簇.测试结果表明,改进后的FAT文件系统能够在可控范围内可靠地存储FAT表,同时有效地均衡了各个簇的擦写次数,这些都增强了FAT文件系统的可靠性.

A Mechanism for Enhancing Reliability of FAT File System Faced Flash Memory

When FAT file system is used for flash memory,the storage location of file allocation table is uncertain,and the erase count between clusters is imbalance,all these result in the decrease of reliability.For these problems,this paper proposes two solution,they are controllable migration of file allocation table and wear leveling between clusters.The former reserves a number of blocks in flash to store file allocation table,when updating file allocation table,it selects the block whose erase count is minimum in all reserved blocks.It also reserves a block in flash to record entrance address of the newest file allocation table.The latter reserves a block in flash to record erase count of each cluster,when allocating space,it selects the free cluster whose erase count is less than erase threshold.According to test result,the improved FAT file system storing file allocation table are controllable and reliable,and it also effectively balances the erase count between clusters,all these enhance the reliability of FAT file system.