Fdisk

fdisk allows you to manipulate slices (another word for partition) on a disk. PC hardware limits a disk to four physical slices and a number of logical slices. Most UBO fdisk utilities don't support logical slices but have their own disklabel to greatly increase the number of partitions from the fdisk's four.

Here is a sample OpenBSD fdisk where OpenBSD used exclusively on the disk.

# fdisk wd0
Disk: wd0       geometry: 3133/255/63 [50331648 Sectors]
Offset: 0       Signature: 0xAA55
           Starting         Ending         LBA Info:
#: id      C   H   S -      C   H   S [       start:        size ]
-------------------------------------------------------------------------------
 0: 00      0   0   0 -      0   0   0 [           0:           0 ] unused      
 1: 00      0   0   0 -      0   0   0 [           0:           0 ] unused      
 2: 00      0   0   0 -      0   0   0 [           0:           0 ] unused      
*3: A6      0   1   1 -   3132 254  63 [          63:    50331582 ] OpenBSD     
#