嵌入式设备的FAT文件系统设计

随着嵌入式系统的复杂性的不断提高，在嵌入式系统中也需要存储和管理大量数据。闪存的众多特性使其成为嵌入式系统的首选存储设备，而FAT文件系统又以其短小精悍的特点被广泛应用的资源有限的嵌入式系统。该文重点讨论了以磁盘为载体的文件系统向以闪存芯片为载体的嵌入式文件系统移植过程中所需要解决的缓冲问题，并最终采用了一种结构上属于哈希双向链表，结合二次机会算法与最久未使用替换算法的动态维护的缓冲区。

The Implementation of FAT Filesystem for Embedded Device

With the increasement of the complexity of embedded system, the capability of storage and manipulation of mass data is definitely required. Flash, with its various unique features, is regarded as the first choice of the storage device for embedded system. In addition, concerning of its compact size and proper capability, DOS filesystem is widely adopted in the embedded system which only possesses limitary resource. Concerning the fact that the structure for hard disk and FLASH differ variously from each other, this article emphasizes the design of buffer zone in the procedure carried out during the transplantation of file system from hard disk to FLASH by the means of comparing several algorithms commonly used. Finally, twice chance algorithm, accompanied by LRU and dynamic kept buffer zone, based on a double- forward link list and a hash table is adopted.