OXO

OXO
OXO played in an EDSAC simulator for the Classic Mac OS
Developer(s)	A S Douglas
Platform(s)	EDSAC
Release	UK: 1952
Genre(s)	Puzzle
Mode(s)	Single-player

OXO or Noughts and Crosses is a video game developed by A S Douglas in 1952 for the Electronic Delay Storage Automatic Calculator (EDSAC) computer, which simulates a game of noughts and crosses, also called tic-tac-toe. It was one of the first games developed in the early history of video games. Douglas programmed the game as part of a thesis on human-computer interaction for the University of Cambridge. The EDSAC was one of the first stored-program computers, with memory that could be read from or written to, and had three small cathode ray tube screens to display the state of the memory; Douglas re-purposed one screen to demonstrate portraying other information to the user, such as the state of a noughts and crosses game. After the game served its purpose, it was discarded on the original hardware but later successfully reconstructed. OXO, along with a draughts game by Christopher Strachey completed around the same time, is one of the earliest known games to display visuals on an electronic screen. Under some definitions it thus may qualify as the first video game, though other definitions exclude it due to its lack of moving or real-time updating graphics.

The Electronic Delay Storage Automatic Calculator (EDSAC) mainframe computer was built in the University of Cambridge's Mathematical Laboratory between 1946 and 6 May 1949, when it ran its first program, and remained in use until 11 July 1958. The EDSAC was one of the first stored-program computers, with memory that could be read from or written to, and filled an entire room; it included three 35×16 dot matrix cathode ray tubes (CRTs) to graphically display the state of the computer's memory. As a part of a thesis on human-computer interaction, Alexander S. Douglas, a doctoral candidate in mathematics at the university, used one of these screens to portray other information to the user; he chose to do so via displaying the current state of a game.