Communication between a computer and other devices is normally handled through an intermediary device known as a controller. In the case of a personal computer, a controller has the physical form of a circuit board (the motherboard). From there the controller connects via cables to peripheral devices within the computer or perhaps to a connector on the back of the computer where external devices can be attached. These controllers are often small computers within themselves, each with its own memory circuitry and CPU that performs a program directing the activities of the controller.…
