 A parallel development in MS-DOS / PC DOS which allowed an increase in the maximum possible FAT size was the introduction of multiple FAT partitions on a hard disk.To allow the use of more FAT partitions in a compatible way, a new partition type was introduced in PC DOS 3.2 (1986), the "extended partition" (EBR), which is a container for an additional partition called "logical drive".Since PC DOS 3.3 (April 1987), there is another, optional extended partition containing the next "logical drive", and so on.