Control
Controlunits are in charge of the computer. Control units fetch and decode machineinstructions. Control units may also control some external devices.
Abus is a set (group) of parallel lines that information (data,addresses, instructions, and other information) travels on inside a computer.Information travels on buses as a series of electrical pulses, each pulserepresenting a one bit or a zero bit (there are trinary, or three-state, buses,but they are rare). An internal bus is a bus inside the processor,moving data, addresses, instructions, and other information between registersand other internal components or units. An external bus is a bus outsideof the processor (but inside the computer), moving data, addresses, and otherinformation between major components (including cards) inside the computer.Some common kinds of buses are the system bus, a data bus, an address bus, acache bus, a memory bus, and an I/O bus.