YAFFS
From Just Solve the File Format Problem
YAFFS (Yet Another Flash File System) is a file system intended for flash memory devices, specifically the NAND variety. It is targeted at storage devices that are sharply limited in how many times a section of memory can be rewrited, by enforcing a "write once rule" and keeping track of which sections of memory have already been used and should be avoided even if they're not part of a file in current use.