The history of computer technology has involved a sequence of changes ~ZT\ one type of physical realization to another from gears to relays to valves to ~3nsistors to integrated circuits and so on. Today's advanced lithographic *r-:hniques can squeeze fraction of micron wide logic gates and wires onto the s^face of silicon chips. Soon they will yield even smaller parts and inevitably each a point where logic gates are so small that they are made out of only a -^ndful of atoms; i.e. the size of the logic gates become comparable to the size r atoms."
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