FAT12: The oldest type of FAT used a 12-bit binary number to hold the cluster number. A volume formatted using FAT12 could hold a maximum of 4,086 clusters, minus a few values (to allow for reserved values to be used in the FAT). FAT12 was therefore most suitable for very small volumes, and was used on floppy disks and very small hard disk partitions. (Less than 16MB)