Device drivers
The main purpose of device drivers include
- device discovery,
- detecting device state changes and
- similar low-level hardware functions
When a device driver is loaded, the events the driver detects are sent to the userspace daemon udevd.
udevd then decides how it will react to the given event.
Major and minor numbers
The correct device driver for a device is identified by the
kernel by the major number of the device driver.
The minor number is used by the device driver itself. The meaning changes from driver to driver.