Star Trek is a text-based mainframe computer game written by Don Daglow on a PDP-10 timesharing computer at Pomona College in 1972, and upgraded periodically through 1974, including contributions by Jonathan Osser. The game was picked up by the DECUS user group in 1972 and distributed to many universities and other PDP-10 installations around the world, often appearing on the same systems alongside the Star Trek text game. Daglow only learned of the game's publication when he began receiving fan letters at his college dorm. The two Star Trek games were each among the most popular mainframe computer games of the 1970s, which were played for free on college systems.
The player began the game by entering their own name (or, if they preferred, "Kirk") as the name of the ship's captain. Spock would then declare that a Klingon, Romulan or Tholian vessel had appeared on the Enterprise's sensors, and announce its position.
The game described the action by printing a script displaying the characters' dialogue in traditional dramatic format. Daglow was a writing major studying playwriting with professor Steven Young, but prior games (including a horse racing game where players guessed the winner) had already used the idea of printing out the dialogue of a fictional character to narrate the action.
On each turn, Sulu or Chekov updated the enemy's position and Uhura asked for the player's orders, and a number (initially from 1 to 10, later from 1 to as high as 19) could be entered to tell the crew of the Enterprise what to do. Options included moving closer or farther away from the enemy vessel, and firing phasers or photon torpedoes. The different weapons each had optimal ranges.