Fritz Whittington kirjoitti viestiss� (l�tysaika torstai, 25. elokuuta 2005 01:26): > In 1977, > I designed and built a gadget that read paper tape a lot > faster than the Teletype could, and I'm a software engineer, > not a hardware designer! What makes paper tape so easy is > that the sprocket hole gives you a positive indication that a > set of holes is ready to be sensed at a fairly precise offset > distance away. Nine teeny light sensors mounted in the proper > pattern, and nine input bits on the computer to read them. > Didn't matter if you pulled the tape through at any particular > speed (as long as it wasn't too fast for the computer > software). So, you re-invented the method used by the British Colossus code-breaking machine. http://www.codesandciphers.org.uk/lorenz/rebuild.htm The Colossus actually used the sprocket hole signal as its system clock. -- Markku Kolkka markku.kolkka@xxxxxx
