Alexander Douglas writes OXO for EDSAC
A Cambridge PhD student puts tic-tac-toe on a cathode-ray screen
Quick facts
- Creator
- Alexander S. Douglas
- Machine
- EDSAC, University of Cambridge
- Game
- Noughts and crosses (tic-tac-toe)
- Display
- 35 x 15 dot cathode-ray tube
What happened
Alexander 'Sandy' Douglas, a Cambridge University PhD candidate, wrote a version of tic-tac-toe (called noughts and crosses in Britain) for the university's EDSAC computer as part of his research into human-computer interaction. The program, OXO, let a player choose to move first or let the machine go first, entering moves with a rotary telephone dial while EDSAC drew the three-by-three board on a 35-by-15 dot cathode-ray tube, one of the machine's three small built-in displays. Because EDSAC was a one-of-a-kind research machine at Cambridge, almost no one outside the university ever played it.
Why it matters
OXO is among the earliest programs to draw a genuine picture, rather than blinking lights or printed text, on an electronic screen in response to player input. It shows the graphical game arriving as a byproduct of academic computer science, years before anyone tried to sell games commercially.
How we know
The Computer History Museum's 1952 timeline entry describes the program, its author, the EDSAC hardware, and the rotary-dial input method from its own historical record.
Sources
- Computer History Museum. 1952: Timeline of Computer History · Reputable sourcecomputerhistory.org · The domain "computerhistory.org" is on our Reputable source registry. · Link is live and its text matches the event's key terms (Jul 2026)
- David Winter, Pong-Story. A.S. Douglas 1952 Noughts and Crosses game · General sourcepong-story.com · Cited as a "reference" source (no stronger domain match). · Link is live and its text matches the event's key terms (Jul 2026)
See something wrong? . Corrections with a source get fixed fastest.
Part of a timelineHistory of Video Games32 events · From a radar-lab curiosity to the biggest entertainment medium on EarthView all →