Disklabel

Disklabel sits on the physical disk (wd0c, sd0c, or da0s1c) and has an internal table of partitions on this disk. Disklabel itself is a command to create these partitions.

In openbsd disklabel can be used interactively with disklabel -E option. This is also the same as the OS install.

OpenBSD allows 16 partitions using disklabel wd0 shows the partition table

{drive data cut}
16 partitions:
#                size           offset  fstype [fsize bsize  cpg]
 a:          2104452               63  4.2BSD   2048 16384    1 
 b:          2104515          2104515    swap                   
 c:         50331648                0  unused      0     0      
 d:          2104515          4209030  4.2BSD   2048 16384    1 
 e:         44018100          6313545  4.2BSD   2048 16384    1 

This is a sample OpenBSD disklabel on a 24 GB drive. Partition a is the root disk, historically the root drive is always on a. Partition b is for swap, partition c represents the entire disk and d is /var filesystem. The rest (partition e) is for the /usr filesystem.