Years before the Magnavox Odyssey (1972) and the Atari 2600 (1977), there was Spacewar, created in 1961 by Steve Rusell to run on a DEC PDP-1. Contributing to its success was the fact that the DEC PDP-1 allowed more than one user to interact at the same time. So what better program to create than the first galactic conflict? Spacewar was an epic space battle between two players who had to rotate, thrust and fire simultaneously all while avoiding the gravitational pull of the local star.
"If I hadn't done it, someone would've done something equally exciting, if not better, in the next six months. I just happened to get there first." - Steve Russell aka "Slug" on inventing Spacewar.
Predecessors
There were at least two far-lesser-known predecessors.
OXO (1952), a tic-tac-toe program that had no real-time interaction and displayed progress through updating screens after a move was made. The game was developed by A.S. Douglas in 1952, written for an Electronic Delay Storage Automatic Calculator (EDSAC). EDSAC on one of the first stored-program calculators with memory that could be read from or written to and three small cathode ray tube screens to display the state of the memory. He created the demo for his thesis on human-computer interaction at the University of Cambridge. After the demo, it was discarded.
Tennis for Two (1958) the predecessor to Pong was written for an oscilloscope and controlled by two aluminum controllers with a button and a knob to hit the ball and control the angle of the shot. The Tennis for Two prototype was dismantled so the components could be used for other projects. It remained forgotten until the '70s when it was used during patent lawsuits between Magnavox and Ralph H. Baeur, considered to be the inventor of video games, specifically the home video game consoles using a TV.
Game Inspiration
In 1962, Steve was a young computer programmer from MIT and was inspired by the writings of E. E. "Doc" Smith. The Lensman series centered on the Galactic Patrol, defenders of the universe. , The series followed the book Triplantary which was published in Amazing Stories in 1934. As with many science-fiction books of the time, much of the action included intergalactic space battles with spaceships rocketing into other worlds, fighting every step of the way. What better scenario to use for the first game?
Development
It took the team about 200 man-hours to write the first version of Spacewar. Russell wrote Spacewar on a PDP-1, an early DEC (Digital Equipment Corporation) interactive mini computer which used a cathode-ray tube type display and keyboard input. The computer was donated to MIT from DEC, who hoped MIT's think tank would be able to do something remarkable with their product. The resulting computer game, Spacewar, wasn't what they had in mind but DEC later provided the game as a diagnostic program for their customers.
The PDP-1's operating system was the first to allow multiple users to share the computer simultaneously. This was perfect for playing Spacewar, which was a two-player game involving warring spaceships firing photon torpedoes. Each player could maneuver a spaceship and score by firing missiles at his opponent while avoiding the gravitational pull of the sun. The spaceship and missile trails are not because of some sophisticated programming but because the CRT monitor slowly fading when lit.
For the first few months after the hardware was installed, the PDP-1 programming community at MIT focused on simpler programs to work out how to create software for the computer. During this period, Russell visited his old friends in the community frequently and described the Spacewar! concept to them. Russell hoped someone would implement the game, but had no plans to do so himself. Other members of the community felt he was the logical choice to create the game, however, and began pressuring him to program it. In response, Russell began providing various excuses as to why he could not do so. One of these was the lack of a trigonometric function routine needed to calculate the trajectories of the spacecraft. This prompted Alan Kotok of the TMRC to call DEC, who informed him that they had such a routine already written. Kotok drove to DEC to pick up a tape containing the code, slammed it down in front of Russell, and asked what other excuses he had.
Russell, later explaining that "I looked around and I didn't find an excuse, so I had to settle down and do some figuring", started writing the code around the time that the PDP-1's display was installed at the end of December 1961. The game was developed to meet three precepts Russell, Graetz, and Wiitanen had developed for creating a program that functioned equally well as an entertainment experience for the players and as a demonstration for spectators: to use as much of the computer's resources as possible, to be consistently interesting and therefore have every run be different, and to be entertaining and therefore a game. It took Russell, with assistance from the other programmers—including Bob Saunders and Steve Piner (but not Wiitanen, who had been called up by the United States Army Reserve)—about 200 total hours to write the first version of Spacewar!, or around six weeks to develop the basic game. It was written in the PDP-1's assembly language.
Arcade Release
Spacewar!, the arcade cabinet version was designed by Larry Rosenthal, based on his memories of playing fellow MIT graduate Stephen Russell’s computer classic. His brief exposure to Spacewar comes during a tour of the MIT campus as a possible freshman candidate in 1968. Later Larry built his own version around a vector display, installing the game in an arcade near the Berkley campus. Differing from the current raster graphics monitors of the day, a vector graphics game draws sharp, high-contrast shapes on the screen using straight lines. Rosenthal shops the system to numerous manufacturers while demanding an unheard of 50 percent take in the game’s profits. He calls upon companies such as Atari, who blow him off with Bushnell possibly still stinging from the failure of his own Spacewar! translation, Computer Space. Hungry for a new, original game, Cinematronics snaps it up. In a move they ruefully regret later, theirs is merely a licensing agreement with Rosenthal, allowing him to retain ownership of the technology.
The game was popular, not only because of the ability for two people to battle it out in real-time, but because there were over 250 modifications available. The playfield could be setup to have 'bounce back' from the edges, or the 'expanded universe' where players would disappear from one side of the display and appear on the other. The sun could be turned off, resulting in a 'black hole' effect. Negative gravity or no gravity was another option. With the Beginner, Intermediate and Expert modes each having a speed setting, it could create some challenging wars, especaily for noobs.
One item of note, one of the two spaceships in Space Wars looks very similar in design to Star Trek's Enterprise, first seen in September, 1966. Coincidence? I think not.
Nolan Bushnell and Atari
Russell transferred to Stanford University, where he introduced computer game programming and Spacewar to an engineering student named Nolan Bushnell. Bushnell later founded Atari and eventually produced a Spacewar clone call Computer Space. But it was a commercial failure. Fortunately, in 1973, Atari had purchased Cyan Engineering located in Grass Valley, CA. and the company created the Atari VCS. Later renamed to the 2600, its key difference was the ability to use cartridges to easily switch between games without requiring any computer skills, making gaming easily available to the consumer market.
Legacy
It would take over 20 years but the transition from a mini-frame computer system to arcade cabinets and eventually the home market had started. Spacewar's real legacy was to demonstrate the possibilities for taking gaming from card tables to electronic cabinets and then home entertainment systems. It is at the top of Game Canon, the list of games that are preserved by the Library of Congress.