 These values were arranged so that the entry would also function as an "trap-all" end-of-chain marker for all data clusters holding a value of zero.Additionally, for FAT IDs other than 0xFF (and 0x00) it is possible to determine the correct nibble and byte order (to be) used by the file system driver, however, the FAT file system officially uses a little-endian representation only and there are no known implementations of variants using big-endian values instead.86-DOS 0.42 up to MS-DOS 1.14 used hard-wired drive profiles instead of a FAT ID, but used this byte to distinguish between media formatted with 32-byte or 16-byte directory entries, as they were used prior to 86-DOS 0.42.