Freeway Crossing
Around 1971, student programmer Michael Irrgang wrote a video game (one of the earliest) called Freeway Crossing, for the IMLAC PDS-1. He wrote it for Dr. Earl Hunt, for use in a psychological study at University of Washington involving reaction times. The game runs on an early version of the PDS-1 - the so-called "Alpha machine". The code was assembled using punched cards on an XDS Sigma 5 at the Computer Science department. Irrgang retained a copy of the assembly listing, which was later scanned and transcribed.
The object of the game is to run a car vertically up the display without being hit by any of the six cars running horizontally. This game was probably the first in the genre typically exemplified by the Frogger arcade game.
In 2025, the game was updated with conditionals for also running on a IMLAC PDS-1 "Graphics machine" variant, and tested on a real one.
External links
- Assembly listing
- Scanned listing transcribed into text
- Screen Addressing in FREEWAY (1970) for the IMLAC PDS-1
- The game running on an emulator
- The game running on a real IMLAC PDS-1
- Paper by Earl Hunt describing the UofW CS facilities, including the Sigma 5 used to assemble the game, and the newly installed IMLAC PDS-1.
