The udev program is designed to simplify the chaos that had overtaken the /dev directory with huge numbers of mostly unneeded devices. Understanding how udev works is key to dealing with devices, especially hotplug devices and how they can be managed. Although udev is designed to provide persistent device naming, I find that there are some issues with this and devices such as multiple Network Interface Cards (NICs) can be (apparently) arbitrarily renamed after upgrades from Fedora 11 to fedora 12 or from pre-udev releases of Fedora to post-udev releases.

Here are links to two papers written by the authors of udev. They provide insight into the details of udev and how it is supposed to work.

• Udev on Fedora by Harald Hoyer
• Kernel Korner – udev — Persistent Naming in User Space by Greg Kroah-Hartman