Block devices
Block devices are also associated with a device node that also has major and minor numbers.
Tip
Although character and block devices are identified using major and minor numbers, they are in different namespaces. A character driver with a major number of 4 is in no way related to a block driver with a major number of 4.
With block devices, the major number is used to identify the device driver, and the minor number is used to identify the partition. Let’s look at the MMC driver on the BeaglePlay:
# ls -l /dev/mmcblk*
brw-rw---- 1 root disk 179, 0 Aug 7 13:25 /dev/mmcblk0
brw-rw---- 1 root disk 179, 256 Aug 7 13:25 /dev/mmcblk0boot0
brw-rw---- 1 root disk 179, 512 Aug 7 13:25 /dev/mmcblk0boot1
brw-rw---- 1 root disk 179, 1 Aug 7 13:25 /dev/mmcblk0p1
brw-rw---- 1 root disk 179, 2 Aug 7 13:25 /dev/mmcblk0p2
brw-rw---- 1 root disk 236, 0 Aug 7 13:25 /dev/mmcblk0rpmb
brw-rw---- 1 root disk 179, 768 Feb 4 09:42 /dev/mmcblk1...
