Noughts And Crosses - The oldest graphical computer game


Introduction

Electronic calculators appeared between the two world wars, mostly because of the need of calculating balistic calculations. Each balistic weapon used a specific hand calculated table of trajectories. Calculating a single table took a considerable amount of time. Electronic calculators partially solved this problem until computers arrived. They were the next generation of electronic calculators: they executed a sequence of instructions called program (software).

In the 1940s, computers had very limited abilities and could only execute a very short program. But they were revolutionar. They could compute a table of square roots, solve complex equations, etc.


EDSAC, first computer (United Kingdom, 1949)

The first programs in the world were written on EDSAC, a unique computer built in 1949 at the University of Cambridge in the United Kingdom. One computed a table of square roots, another computer a table of prime numbers.

Early computers like EDSAC occupied a huge place, mainly because they used vaccuum tubes (the semi-conductors predecessors) which took much more place than a microprocessor and required a lot of power. Computers were also limited by two other factors: their speed and their memory. Computing a typical arithmetic table often required many hours or even days (something that engineers were used to).

EDSAC used 32 mercury delay lines (or "long tanks") storing 1024 words. Each tank stored 16 words of 35 bits. EDSAC also used 3 monitor tubes (CRTs), one of which displayed the contents of one of the long tanks. Thus, the display was a matrix of 35 x 16 dots. EDSAC was not very stable but worked pretty well. It operated 600 instructions per second.


Noughts and Crosses by A.S. Douglas

The picture shown on the top of this page is a simulation of Noughts And Crosses, a Tic-Tac-Toe game programmed in 1952 by A.S. Douglas who was passing his PhD degree at the University of Cambridge. His ingenious idea was the use of the tank display CRT as 35 x 16 pixel screen to display his game.

The game was played against the machine and the player determined who played first (EDSAC / USER). Once the game started, the player specified where he wanted to place his nought or cross using a mechanical telephone dialer.

The reason why A.S. Douglas programmed this game is his PhD dissertation about Human-Computer interraction. People willing to read this dissertation will need to visit the library of the University of Cambridge in order to obtain a copy.

People willing to simulate this game can follow this link to download the latest version of the EDSAC simulator (both MAC and PC versions are available). The software includes a number of programs and subroutines, recent contributions from EDSAC amateurs, as well as a very detailed documentation for those willing to write EDSAC programs.

Noughts and Crosses is considered as being the first real graphical computer game and preceeds Space War by almost a decade. One might wonder why it had no success outside of the University of Cambridge. The reason is obvious: EDSAC was unique, so nobody could play the game outside of the University.

Below is the text output of a game I tried on the EDSAC Simulator...: