Allows the user and the computer to communicate with each other. User Interfaces Allows the user and the computer to communicate with each other.

Three different types of User interfaces Command-line interface Menu driven interface Graphical User Interface (G.U.I.)

Command-line User enters structured commands through the keyboard. The user must remember the exact command and the syntax MS DOS (Disk operating System) and Unix are O.S. that use command line E.g. start http://msn.com

Menu Driven Interface List of options that allow the user to select from.

Graphical User Interface WIMP (windows icons menus pull down and pop ups Easy to understand, very user friendly Use both mouse and keyboard Windows XP, Vista