udev's main task is to create and remove device nodes in /dev when a
device is discovered or removed from the system. udevd receives all
hotplug events via kernel netlink messages and dispatches them
according to rules in /lib/udev/rules.d/. Matching rules may name a
device node, create additional symlinks to the node, call tools to
initialize a device, or load needed kernel modules.

Authors:
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Greg Kroah-Hartman
Kay Sievers