Four common functions of computer system are : Input Output Processing Storage Input The Computer receives its data from input devices as raw dat a which is processed in human readable form with the help of other PC devices. The primary input devices of computer system are:- Keyboard Mouse Scanner Trackball Lightpen Joystick Output The output devices of computer receives data from system and process the data in human readable form. Common Output devices are :: Printers Monitors Speakers Headphones Projectors Processing Processing is the function of computer system when the data is received from the memory for further processing. Storage Two storage unit of PC are :- Primary...