"WarGames", an Early Science Fiction Film Focusing on Hacking and War Games Simulations

In 1983 Matthew Broderick, Dabney Coleman, John Wood, and Ally Sheedy starred in the Cold War science fiction film WarGames
written by Lawrence Lasker and Walter F. Parkes and directed by John Badham.

"The film follows David Lightman (Broderick), a young hacker who unwittingly accesses War Operation Plan Response (WOPR), a United States military supercomputer originally programmed to predict possible outcomes of nuclear war. Lightman gets WOPR to run a nuclear war simulation, believing it to be a computer game. The computer, now tied into the nuclear weapons control system and unable to tell the difference between simulation and reality, attempts to start World War III" (Wikipedia article on WarGames, accessed 10-2020)