Design and Implementation of a FAT File System for Reduced Cluster Switching Overhead

In this paper, we present design and implementation of a New FAT file system (NFAT) for mobile multimedia devices. Conventional file system which has been used for personal computers is the FAT and it is still adopted for most of current portable devices. The major problem of the FAT is overhead due to cluster switching which involves retrieving and updating of cluster connection information saved on the file allocation table. Because of this overhead, response time of file read and write operation cannot be guaranteed in the FAT. This paper proposes the NFAT which guarantees expected response time by reducing cluster switching overhead when it reads and writes data for portable multimedia devices. To verify our proposal, we have implemented a prototype NFAT file system on ARM9 development board and a Secure Digital Card. The experimental results show that the NFAT does not have irregular response time when performing read/write operations. Therefore, the NFAT is suitable file system for mobile devices which have real-time requirements in reading and writing multimedia data.