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This is my write up on the very first game ever: Spacewar. The role of the tech greats in the development of the first game are highlighted. Going down memory lane on the computing industry gave me a sense of nostalgia.

Published in: Entertainment & Humor
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  1. 1. SpacewarIn the annals of hacking history, there are many great computing machines however; nonewould change the history of computing as much as the (Programmed Data Processor-1) PDP-1. Designed by Digital Equipment Corporation (DEC), it was donated to the MIT labs. ThePDP-1 replaced the TX-0. The TX-0 was the world’s first personal computer. Costing $3million in the late fifties, it would trigger the formation of a dedicated community of hackersaround it.The PDP-1 however would go on to make history. First produced in 1960, it would be on thiscomputer that music would first be created via a computer program and the first computergame would be created.When the PDP-1 was delivered to MIT, it came with a simple collection of systems software,which the TX-0 hackers considered completely inadequate. The TX-0 hackers had becomeaccustomed to the most advanced interactive software anywhere, a dazzling set of systemsprograms, written by hackers themselves and implicitly tailored to their relentless demandsfor control of the machine.Alan Kotok already an accomplished TX-0 hacker designed a debugger for the PDP-1 calledthe DDT. It was him and a dedicated team of hackers that would write their own assemblerover a weekend. They accomplished this feat by reworking code from the TX-0 and notsleeping!During the summer of 1961, a plan for the most elaborate hack yet was devised. SteveRussell and his friends came up with a plan to create an elaborate display hack on the PDP-1
  2. 2. using the CRT screen. They collectively agreed that the most effective demonstration of thecomputer’s magic would be a visually striking game. Given their collective background inscience fiction, the team decided to build a game that would feature space warfare.Steve Russell delayed starting work on the project for several months. When pressuremounted from other hackers, he muttered that he had not started the project because he hadnot figured out how to write the elaborate sine-cosine routines necessary to plot thespaceships. Given the spirit of hackerdom, a library was found for the trigonometric functionsand work could start.At that point, Steve Russell had no excuse. So he spent his off-hours writing this fantasyPDP-1 game, the likes of which no one had seen before. He began in December 1961 andwhen the calendar wrapped around to 1962, he was still hacking. By that time, Russell couldproduce a dot on the screen that you could manipulate: by flicking some of the tiny toggleswitches on the control panel, you could make the dots accelerate and change direction.He then set about making the shapes of the two rocket ships: both were classic cartoonrockets, pointed at the top and blessed with a set of fins at the bottom. To distinguish themfrom each other, he made one chubby and cigar-shaped with a bulge in the middle, while thesecond he shaped like a thin tube. Russell used the sine and cosine routines to figure out howto move those shapes in different directions. Then he wrote a subroutine to shoot a “torpedo”(a dot) from the rocket nose with a switch on the computer. The computer would scan theposition of the torpedo and the enemy ship; if both occupied the same area, the programwould call up a subroutine that replaced the unhappy ship with a random splatter of dotsrepresenting an explosion. (That process was called “collision detection.”)In the later stages of programming, Bob Saunders helped Steve Russell out, and they hackeda few intense six-to-eight-hour sessions. Sometime in February, Russell unveiled the basicgame. There were the two ships, each with thirty-one torpedoes. There were a few randomdots on the screen representing stars in this celestial battlefield. You could manoeuvre theships by flicking four switches on the console of the PDP-1, representing clockwise turn,counter clockwise turn, accelerate, and fire torpedo.Once a rough version of the game once shown to the community of hackers, there was nogoing back! Since the code was open-source, modifications beyond the original design weremade to it.Peter Samson for instance loved the idea of Spacewar, but could not abide the randomlygenerated dots that passed themselves off as the sky. Real space had stars in specific places.“We’ll have the real thing,” Samson vowed. He obtained a thick atlas of the universe, and setabout entering data into a routine he wrote that would generate the actual constellationsvisible to someone standing on the equator on a clear night. All stars down to the fifthmagnitude were represented; Samson duplicated their relative brightness by controlling howoften the computer lit the dot on the screen which represented the star.
  3. 3. Another programmer, named Dan Edwards was dissatisfied with the unanchored movementof the two duelling ships. He felt it made the game merely a test of motor skills. He figuredthat adding a gravity factor would give the game a strategic component. So he programmed acentral star-a sun in the middle of the screen.The variations made to the game where endless. Spacewar was played a lot of times. So muchso that Russell eventually wrote a subroutine that would keep scores (High Scores Screen). Inthe course of playing Spacewar, the tedium involved in working the switches on the consoleof the PDP-1 led to the invention of the first computer joysticks! The first computer joystickshad their control boxes made of wood with Masonite tops. They had switches for rotation andthrust as well as a button for hyperspace.Like the hackers’ assemblers and other programs, Spacewar was never sold. It was placed inthe drawer for anyone to access, look at, and rewrite as they saw fit. Gradually the popularityof the program would spread and DEC engineers would use it as a final diagnostic programon PDP-1s before they rolled them out the door.SourcesHackers Heroes of the Computer Revolution by Steven LevyWikipedia