Linux Device Drivers Development

The concept behind major and minor

Character devices are populated in the /dev directory. Do note that they are not only files present in that directory. A character device file is recognizable by its type, which we can display thanks to the ls -l command. Major and minor identify and tie the devices with the drivers. Let's see how it works by listing the content of the /dev directory (ls -l /dev):

[...]drwxr-xr-x 2 root root 160 Mar 21 08:57 inputcrw-r----- 1 root kmem 1, 2 Mar 21 08:57 kmemlrwxrwxrwx 1 root root 28 Mar 21 08:57 log -> /run/systemd/journal/dev-logcrw-rw---- 1 root disk 10, 237 Mar 21 08:57 loop-controlbrw-rw---- 1 root disk 7, 0 Mar 21 08:57 loop0brw-rw---- 1 root disk 7, 1 Mar 21 08:57 loop1brw-rw---- 1 root disk 7, 2 Mar ...