/dev/bsak (AKA BSAK device) is an integral part of all modern computers. Although it's name comes from the *nix world, it applies equally well when referring to the Microsoft operating system and the people who use it.

In the unix world, the set of devices attached to ones computer are stored in the /dev special directory in the filesystem (called the /dev filesystem, or virtual directory.) /dev/bsak is a particularly troublesome device that tends to have a habit of spewing out incomprehensible data and royally screwing up a machine. Unfortunately for computers everywhere, every computer still has one, and they seem to be multiplying.

BSAK = Between Seat And Keyboard

(see PEBKAC, Operator error)