In this work, we present a novel mobile multimedia file system, MNFS, which is specifically designed for NAND flash memory. It is designed for mobile multimedia devices such as MP3 player, Personal Media Player (PMP), digital camcorder, etc. Our file system has three novel features important in mobile multimedia applications:(1) predictable and uniform write latency,(2) quick file system mount, and (3) small memory footprint. We implement the proto-type file system on ARM9 embedded platform. In experiments, MNFS exhibits uniform I/O latency for sequential write operation. It is mountable within 0.2 seconds, and available with only 34Kbytes heap memory for 128Mbytes volume. Compared to YAFFS which is the de facto standard file system for NAND flash memory, the mounting time is 30 times faster and the heap memory usage is only 5% of YAFFS usage.