Source : Free On-Line Dictionary of Computing

vannevar
     
         /van'*-var/ A bogus technological prediction or a
        foredoomed engineering concept, especially one that fails by
        implicitly assuming that technologies develop linearly,
        incrementally, and in isolation from one another when in fact
        the learning curve tends to be highly nonlinear, revolutions
        are common, and competition is the rule.  The prototype was
        Vannevar Bush's prediction of "electronic brains" the size of
        the Empire State Building with a Niagara-Falls-equivalent
        cooling system for their tubes and relays, a prediction made
        at a time when the semiconductor effect had already been
        demonstrated.  Other famous vannevars have included
        {magnetic-bubble memory}, {LISP machines}, {videotex}, and a
        paper from the late 1970s that computed a purported ultimate
        limit on areal density for {integrated circuits} that was in
        fact less than the routine densities of 5 years later.
     
        [{Jargon File}]
     
        (2000-02-29)