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Down the Hyper-Spatial Tube: Spacewar and the Birth of Digital Game Culture
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Down the Hyper-Spatial Tube: Spacewar and the Birth of Digital Game Culture

June 1, 2007 Article Start Previous Page 3 of 4 Next

Called the “Needle” and the “Wedge”, the ships were piloted by two players who faced off in a deadly arena, firing torpedoes at one another as they dodged and spun, fighting the pull of inertia as well as each other. Because it was difficult to judge the ships’ relative speed on the black screen, Russell created a random star field to fill the background.

Once the basic game was in place, the programmers began a series of hacks to modify and extend its play. Through their ad-hoc efforts, Spacewar moved beyond its origins as a demonstration program and became a fully realized game.

Originally controlled from input switches on the PDP-1’s frame, Spacewar was awkward to play, giving the person nearer to the CRT an advantage. Tech Model Railroad members quickly pieced together hand-held controllers out of spare switches, plywood, and Bakelite.

Russell’s random dot background was discarded and replaced by an accurate star field called “Expensive Planetarium”. Programmed by Peter Samson, Expensive Planetarium used star chart data to display a night sky that accurately showed the constellations, including the individual stars’ varying magnitudes.
In J.M. Graetz’s article “The Origin of Spacewar!” reprinted in Supercade by Van Burnham, Russell said, “Dan Edwards was offended by the plain spaceships, and felt that gravity should be introduced. I pleaded innocence of numerical analysis and other things, so Dan did the gravity calculations.”

Introducing a strategic element to the game, Dan Edwards devised the “Heavy Star”, a burning sun in the middle of the screen whose gravity affected the motion of the ships. If ships did not maintain thrust the Heavy Star would slowly draw them down into its fire, forcing players to consider its mass when vectoring their attacks.

Finally, Graetz created the Hyperspace jump. If things were getting dicey, panicked players could hit a jump button and warp their ship out of danger, leaving a delicate photonic stress signature in their wake. However, resorting to hyperspace was a risky maneuver as players had only three chances to use it and its results were unreliable. Ships emerged from hyperspace at a random location on the screen, possibly out of harm’s way or possibly right into the Heavy Star.

By the spring of 1962, the game dreamed up under the influence of cheap sci-fi was finished.

Computer Bums

Not long after completing Spacewar, the hackers began to drift apart, drawn by their own Heavy Stars. Wiitanen was the first to leave, called up for military duty during the Berlin Wall crisis in the fall of ‘61. Russell left for the West Coast and joined Stanford’s AI Laboratory. Graetz and Kotok went to work for Digital while Samson and Edwards moved on to MIT’s new Project MAC laboratory.

But Spacewar had a life of its own, spreading across the computer world like a benign virus. “It was the program that was run into the PDP-1 before it was shipped. It was the last thing--it was used as actually as a final test,” Graetz said. Because the PDP-1’s memory was composed of magnetic cores, small ferrite rings whose polarity indicated whether a bit was 1 or 0, the game stayed in memory even after the power was turned off. “Core memory is non-volatile and once Spacewar was working they just shut the machine down and shipped it. So when the customer set it up and turned it on the first thing they saw was Spacewar,” he explained.

Students at university computer labs embraced the game, drawn to its perfectly tuned combination of twitch and technique. Over the next decade, they would play Spacewar obsessively, holding impromptu late night tournaments. It was ported to every succeeding machine over the years with new generations of hackers adding variations and refinements to the game’s design.

Article Start Previous Page 3 of 4 Next

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