Udev provides a dynamic /dev directory, and hooks userspace into kernel device events. Udev comes with man pages and doumentation included in the source tarball. Here are some online references:

• README file in the udev source tree.
• A library to access udev device information libudev.
• A GObject wrapper of the library gudev.
• Writing udev rules

The latest released tarball of udev is available at: http://www.kernel.org/pub/linux/utils/kernel/hotplug/.

The git development repository of udev is available at: http://git.kernel.org/?p=linux/hotplug/udev.git;a=summary.

Any questions about udev should be addressed to: linux-hotplug@vger.kernel.org.

Here are some historical documents, which do not have much in common with the current udev implemtation:

• The OLS 2003 paper about how udev was originally designed, and why it was created.
• The OLS 2003 presentation that went along with the paper.
• An article about udev and how it works was published in Linux Journal in 2004.
• The last word on how udev and devfs compare.