Source : Free On-Line Dictionary of Computing

elevator controller
     
        An archetypal dumb embedded-systems application, like
        {toaster} (which superseded it).  During one period (1983--84)
        in the deliberations of ANSI X3J11 (the C standardisation
        committee) this was the canonical example of a really stupid,
        memory-limited computation environment.  "You can't require
        "printf(3)" to be part of the default run-time library - what
        if you're targeting an elevator controller?"  Elevator
        controllers became important rhetorical weapons on both sides
        of several {holy wars}.