A Flash File System to Support Fast Mounting and Reliability in NAND Flash Memory

Even though its attractive features such as non-volatility, fast read access time and solid-state shock resistance, NAND flash memory suffers from no-in-place-update, limited erase cycles, and page based read/write operations. JFFS2 and YAFFS, the flash file systems, allocate memory spaces using LFS(Logstructured File System) method to solve the problems. However, because of this, many pieces of a file are scattered through flash memory and the file systems have to fully scan the flash memory to construct the data structures in RAM. This means that it takes a long time to mount such file systems on a large chip and it can be a critical issue to select a flash file system for some devices. In this paper, we design and propose the prototype of a new flash memory file system, RFFS(Reliable Flash File System) which targets mobile devices that require fast booting and fault tolerant file system. We simulated the file system performance and the results shows that RFFS improves the mount time by 50% ~ 80% as flash usage compared to JFFS2 and logging overhead is very small.

Keywords:

NAND flash memory , Flash file system