The major device number refers to a specific device driver. The minor device number specifies a particular physical unit and possibly characteristics of the unit. For disks, the minor number identifies the drive address and the partition. The major and minor device numbers are displayed by the ls -l command.
There are devices that have identical major and minor numbers, but they are designated in one entry as a block device (a b in the first column) and in another entry as a character device (a c in the first column). Notice that such pairs of files have different filenames or are in different directories (for example, /dev/dsk/dks0d1s0 and /dev/rdsk/dks0d1s0).