data represented to users in visual formats such as text, graphics and tables following data processing. makes it apps more attractive and understandable to users
after data has been processed it can be presented to users in visual formats such as text, graphics and tables -gis -reality mining
it is in control of the ram. it checks all requests for syirage space are valid ans allocates accoedingky. it also allocates soace and swaps data in and out