 If partitions to be used by pre-DOS 3.31 issues of DOS need to be created by modern tools, the only criteria theoretically necessary to meet are a sector count of less than 65536, and the usage of the old partition ID (0x04).In practice however, type 0x01 and 0x04 primary partitions should not be physically located outside the first 32 MiB of the disk, due to other restrictions in MS-DOS 2.x, which could not cope with them otherwise.In 1988, the FAT16B improvement became more generally available through DR DOS 3.31, PC DOS 4.0, OS/2 1.1, and MS-DOS 4.0.