The creators of Spacewar! were students and faculty at MIT, which by the 1960s was highly invested in computer science and engineering. The computers of these days were clunky, room-sized behemoths, but MIT had acquired a DEC PDP-1, a much smaller machine (but still the size of three full-size refrigerators).
MIT had also had the good sense to acquire real display monitors and keyboards for its computers. Most computers at this time were limited to punch card readers for input and a printer for output; obviously this setup would make any sort of action game implausible.
DEC had a much different philosophy than the long-supreme IBM Corporation. IBM's vision of the computing industry was that individual users or "clients" would have nothing to do with the actual machine; they would take cards, programs, or tasks to designated operators (often sarcastically referred to as "priests"), who would be the only ones to physically interact with the computer.
The idea was that a corporation or university would contract with IBM for its computing services, whose own employees would handle the day-to-day computer operations. This model had made a great deal of sense in the early days of computers, when only highly trained professionals could operate and maintain them.
DEC saw things differently; individual users should be able to use and program their computers themselves. IBM's philosophy might be compared to a passenger train system; anyone could ride, but its professional engineers were the only ones authorized to operate (or even see) the engine, much less determine routes. DEC was more interested in selling "cars"; once you had one, you could go wherever you wanted and do whatever you wanted to with it. Eventually, DEC's approach would lead to the "user-friendly" hardware and software we enjoy today.
The nerdy members of MIT's Tech Model Railroad Club quickly adopted the PDP-1, spending the bulk of their days studying and writing programs or, "hacks," one of many new words they coined to describe their activities. Though most of these programs consisted of neat math or geometry tricks, Steve "Slug" Russell -- by all accounts something of a slacker -- decided to one-up his friends by designing a fully interactive science fiction game.
Russell's project might have sounded overly ambitious, but members of the Tech Model Railroad Club weren't the type to back down from a challenge. Russell's friends offered him a steady stream of encouragement and helped him stay on track however they could. Far from the secretive and highly competitive world of modern software development, Russell worked in what is now called an "open source" environment, where most code was freely shared and implemented without fear of copyright or patent infringement.
One such addition was Pete Sampson's "expensive planetarium" hack, which replaced the game's random backdrop of stars with an actual star field as seen from Earth. Like modern open source projects, Spacewar! would be routinely hacked and modified as individual programmers or groups saw fit to tack on new features.
When it was finally finished, Spacewar! was an impressive feat indeed. Two players controlled one of two spaceships that circled a small star with powerful gravity. The object of the game was to destroy the opponent's ship with a missile, being careful not to get sucked into the star's gravitational field.
Players could also enter hyperspace, which randomly relocated them somewhere else on the screen. This feature, of course, shows up in the much later Defender (which will be discussed in an upcoming bonus chapter, "Defender: The Joys of Difficult Games"), which also shared similarities with much of the rest of Spacewar!'s control options. Players controlled the game by flipping four switches, but this cumbersome control scheme was quickly replaced with custom boxes that ranged from prototypical game pads to joysticks.
Although Spacewar! would undoubtedly have appealed to many people besides the brilliant minds at MIT, its steep hardware requirements severely limited its availability. Only college students, and probably engineering students at that, had much chance to see and play these early video games. Nevertheless, development of ports and modifications continued throughout the 1970s, including Silas Warner's Orbitwar (1974), which let players fight it out in networked bouts on the pioneering mainframe-based PLATO instructional system.
At the beginning of the 1970s, the arcade industry was limited to pinball and other electromechanical games, and home video game consoles and personal computers really wouldn't get off the ground until much later in the decade. Bushnell, the man who would later found Atari, was an electrical engineer who had played Spacewar! during his computer science studies at the University of Utah until his graduation in 1968.
Bushnell had also worked at Lagoon Amusement Park at Salt Lake City while he was home from school. Like most amusement parks then and now, Lagoon Amusement offered all sorts of challenging games that required a fee to play. It wasn't long before Bushnell began brainstorming ways to bring the geeky magic of Spacewar! to the masses -- and make a huge stack of money in the process.
Bushnell teamed up with a friend named Ted Dabney and began work on a cheap, coin-operated version of Spacewar!. As microprocessors weren't readily available, the two had to work with bulkier TTL (transistor-transistor logic) digital circuits. They built a futuristic cabinet for the game out of fiberglass, and stuck in a modified General Electric 15" black-and-white television for the display.
Even if the game itself wasn't very fun to play, the cabinet looked so exotic that Richard Fleischer used it as a prop in his science fiction film, Soylent Green (1973), which is set in the year 2022! Calling themselves Syzygy, the two had to work long hours repairing broken pinball machines to survive as they sought out a manufacturer for Computer Space. They finally settled on Nutting Associates, who made electromechanical arcade machines.
Computer Space, released November 1971, was far from an exact clone of Spacewar!. It did not, for instance, feature either two-player combat or a gravity well. Instead, a single player controlled a rocket in open space, dodging enemy fire and trying to destroy two computer-controlled flying saucers.
The game was difficult to control, and even though an estimated 1,500 units of a two player version were built with enhanced control panels, the game didn't enjoy the mass appeal that Bushnell had hoped for. As the story goes, Bushnell became convinced that a simpler game would have a better shot at success, an insight that led him to develop Pong. However, Computer Space's unimpressive sales might owe more to its lackluster gameplay than the ignorance or incompetence of players.
Screenshot from Cinematronics' Space Wars.
 For more on Silas Warner, see book Chapter 2, "Castle Wolfenstein (1981): Achtung! Stealth Gaming Steps out of the Shadows".