Anybody who does low-level kernel programming for long enough learns that the hardware is not their friend. Expecting the hardware to be nice is a recipe for disaster; instead, one must treat the hardware as if it were a clever and willful dog. With some effort, it can be made to perform impressive tricks, but, given a moment of inattention, it will snag your dinner from the grill and hide under the couch.
-- Jonathan Corbet. LWN.net