Levy_S-Hackers-Heroes-Computer-Revolution

Slug was not as driven as some of the other hackers. Sometimes he needed a push.After he made the mistake of opening up his big mouth about this program he wasgoing to write, the PDP-1 hackers, always eager to see another hack added to thegrowing pile of paper tapes in the drawer, urged him to do it. After mumblingexcuses for a while, he said he would, but he'd first have to figure out how to writethe elaborate sine-cosine routines necessary to plot the ships' motion.Kotok knew that hurdle could be easily solved. Kotok at that point had beengetting fairly cozy with the people at DEC, several miles away at Maynard. DECwas informal, as computer manufacturers went, and did not regard MIT hackers asthe grungy, frivolous computer-joyriders that IBM might have taken them for. Forinstance, one day when a piece of equipment v/as broken, Kotok called upMaynard and told DEC about it; they said, Come up and get a replacement. By thetime Kotok got up there, it was well after five and the place was closed. But thenight watchman let him go in, find the desk of the engineer he'd been talking to,and root through the desk until he found the part. Informal, the way hackers like it.So it was no problem for Kotok to go up to Maynard one day, where he waspositive someone would have a routine for sine and cosine that would run on thePDP-1. Sure enough, someone had it, and since information was free, Kotok tookit back to Building 26."Here you are, Russell," Kotok said, paper tapes in hand. "Now what's yourexcuse?"At that point, Russell had no excuse. So he spent his off-hours writing this fantasyPDP-1 game the likes of which no one had seen before. Soon he was spending his"on" hours working on the game. He began in early December, and whenChristmas came he was still hacking. When the calendar wrapped around to 1962,he was still hacking. By that time, Russell could produce a dot on the screen whichyou could manipulate: by nicking some of the tiny toggle switches on the controlpanel you could make the dots accelerate and change direction.He then set about making the shapes of the two rocket ships: both were classiccartoon rockets, pointed at the top and blessed with a set of fins at the bottom. Todistinguish them from each other, he made one chubby and cigar-shaped, with abulge in the middle, while the second he shaped like a thin tube. Russell used thesine and cosine routines to figure out how to move those shapes in differentdirections. Then he wrote a subroutine to shoot a "torpedo" (a dot) from the rocketnose with a switch on the computer. The computer would scan the position of thetorpedo and the enemy ship; if both occupied the same area, the program wouldcall up a subroutine that replaced the unhappy ship with a random splatter of dotsrepresenting an explosion. (That process was called "collision detection.")