The main printed circuit board in an electronic device, which contains
sockets that accept additional boards. In a personal computer, the motherboard
contains the bus, CPU and coprocessor sockets, memory sockets, keyboard
controller and supporting chips. Chips that control the video display,
serial and parallel ports, mouse and disk drives may or may not be present
on the motherboard. If not, they are independent controllers that are plugged
into an expansion slot on the motherboard.