In the embedded industry FAT file systems are commonly used on removable memory that needs to be read by/written to by a PC. However typical FAT (File Allocation Table) file system implementations have a inherent weaknesses which can lead to file and directory corruption if the system is interrupted during a write routine. When you open a file to modify it, the normal FAT process overwrites the existing data. If the system were to reset during that process a portion of the file would have been changed before a new image was built. There would be no way to restore the original data. There could also be a directory entry pointing to a cluster chain that no longer exists or a cluster chain with no directory entry.
RTXCfatfile-safe uses a journaling approach which leaves the original file unchanged until either a file flush or file close is called. At that point the system performs an atomic switch of the file state and the new data becomes valid. The system also includes a new function call, fcloseabort() which allows file modifications to be aborted during a write, restoring the original data. This is only possible because the original data is untouched until the entire write/file close process has been completed.
