Online system

Originally a system that allows the computer to work interactively with its user,responding to each instructions as it is given and prompting users for information when nessecary .The term is now most commonly used to refer to large database electronic mail,abd cinferencing systems accessed via a dial up modem these often have tens or hundreds of users from different places-sometimes from different countries-'online' at the same time.
Operating system(OS):This program that controls the basic operation of a cimputer.A typical of Controls the peripherals devices , organize the fuling system,provides means of communicating with the operater and runs other programs
Proprietary operating systems were written forspecific computes but others are accepted standards.These include cp/Mby Digital Research and MS-DOS by Microsoft for micro computers.Unix (devoloped at AT&T's Bell laborataries) is the standard on work-stations ,minicomputers amd super computers it is also used on desktop PCs and mainframes.