The user interface (also known as human computer interface or man-machine interface (MMI)) is the aggregate of means by which people—the users—interact with the system—a particular machine, device, computer program or other complex tool. The user interface provides means of:
* Input, allowing the users to manipulate a system
* Output, allowing the system to indicate the effects of the users' manipulation.
* Input, allowing the users to manipulate a system
* Output, allowing the system to indicate the effects of the users' manipulation.