Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.3 alpha 5/22/85; site osu-eddie.UUCP Path: utzoo!watmath!clyde!cbosgd!osu-eddie!sutter From: sutter@osu-eddie.UUCP (Bob Sutterfield) Newsgroups: net.rumor Subject: Re: Computer Horror Stories Message-ID: <1335@osu-eddie.UUCP> Date: Sun, 16-Feb-86 22:38:27 EST Article-I.D.: osu-eddi.1335 Posted: Sun Feb 16 22:38:27 1986 Date-Received: Mon, 17-Feb-86 06:26:29 EST References: <14700001@hplabsb.UUCP> <476@mmm.UUCP> <9345@ritcv.UUCP> Organization: OSU Instruction & Research Computer Center Lines: 28 Summary: self-destructing hardware A professor of mine told the story of how to bring down a line printer: Your average line printer has 132 hammers arranged across the width of the paper, with letters, numbers, etc arranged on a band that passes between the hammers and the ribbon, which then strikes the paper. The characters on the band are arranged carefully, based upon frequency-of-use statistics. As the appropriate character arrives at column "c" the hammer is actuated and the impression is made. During the printing of an average line, at any particular moment, only some small "n" (maybe 5) of the hammers are actuated at once. Then the band moves one more character position to the left and another sparse group of hammers are actuated. So on until the line is printed, then a linefeed happens. So, if you knew the pattern of the print band, and sent a line with that pattern all in the right places to be struck at once... then the next line you sent had the same characters in the same order, just shifted one to the left... All 132 hammers operating at once, repeatedly, at x00 lines per minute... The most durable printer they found could stand this abuse for about 1.25 pages. They all ended up shredding the ribbon almost immediately, then finally smoking from the power supply about the same time as the platen was chewed up. Some fun, huh? for the third-shift operator! -- ----- Human: Bob Sutterfield Mail: sutter@osu-eddie.UUCP sutterfield-r%osu-20@osu-eddie.UUCP or: sutter@ohio-state.ARPA sutterfield-r%osu-20@ohio-state.ARPA