udev 111-0ubuntu1 (amd64 binary) in ubuntu gutsy

 udev is a collection of tools and a daemon to manage events received from
 the kernel and deal with them in user-space. Primarily this involves
 creating and removing device nodes in /dev when hardware is discovered or
 removed from the system.
 .
 Events are received via kernel netlink messaged and processed according to
 rules in /etc/udev/rules.d, altering the name of the device node, creating
 additional symlinks or calling other tools and programs including those to
 load kernel modules and initialise the device.