FAT File Systems
FAT is a family of filesystems, comprising at least, in chronological order:
- FAT12, a filesystem used on floppies since the late 1980s, in particular by MS-DOS;
- FAT16, a small modification of FAT12 supporting larger media, introduced to support hard disks;
- vFAT, which is backward compatible with FAT, but allows files to have longer names which only vFAT-aware applications running on vFAT-aware operating systems can see;
- FAT32, another modification of FAT16 designed to support larger disk sizes. In practice FAT32 is almost always used with vFAT long file name support, but technically 16/32 and long-file-names-yes/no are independent.
Because those filesystems are very similar, they're usually handled by the same drivers and tools. mkfs.vfat and mkfs.fat are the same tool; an empty FAT16 filesystem and an empty vFAT filesystem look exactly the same, so mkfs doesn't need to distinguish between them. (You can think of FAT16 and vFAT as two different ways of seeing the same filesystem rather than two separate filesystem formats.)