In video gaming, single-player refers to the variant of a particular game where input from only one player is expected throughout the course of the gaming session. A "single-player game" usually implies a game that can only be played by one person, while "single-player mode" usually refers to an option in an otherwise multiplayer (or two-player)(3 on 3)video game that allows for play by one player. The majority of early computer games were single-player. Two-player games appeared with the first personal computers, and 1978 introduced the first multiplayer games, known as MUDs. The early 1990s introduced many games which utilized local area networks and null modems for multiplayer mode. Doom is a notable example of one such game.