 The DCF file system adopted by almost all digital cameras since 1998 defines a logical file system with 8.3 filenames and makes the use of either FAT12, FAT16, FAT32 or exFAT mandatory for its physical layer for compatibility.FAT is also used internally for the EFI system partition in the boot stage of EFI-compliant computers.Hidden FAT filesystems are also used in the UEFI boot partition on modern PCs.