Definition: a flexible/generic mechanism for describing a single device (aka package).

o A device description has some type (could be class with sub-classes), used to match drivers to devices (akin to PCI). o Contains a device's resources (I/O, interrupt, etc) o Contains attributes o Can contain “hints” to the OS for purposes of wiring devices down to drivers and unit numbers.

Definition: a collection of device descriptions organized in a hierarchical structure.

o Can be partial; sub-trees that can be mapped/rooted at runtime.

o Textual representation. At first, the kernel will parse and translate to make it easier to 1) compile-in, 2) load as module, and 3) manually enter while booting. o Bus driver that takes a device tree, parses it and creates the appropriate newbus hierarchy, followed by the standard probe and attach.