Coordination and control of the computer. Control device to receive data. Send the data to the memory. Contact with the display device to put the data from the memory to the display device.
Coordinate and control the computer. Control Input Device Send information to memory. Contact with the display device in order to bring the information from the memory to the display device.
Coordination and control functions of the computer. Control input device. Send data to the memory. Contact with the display device to order the data from the memory to the display equipment.