space-cadet keyboard

space-cadet keyboard n.  A now-legendary device used on MIT
   LISP machines, which inspired several still-current jargon terms
   and influenced the design of {EMACS}.  It was equipped with no
   fewer than *seven* shift keys: four keys for {bucky bits}
   (`control', `meta', `hyper', and `super') and three like
   regular shift keys, called `shift', `top', and `front'.  Many
   keys had three symbols on them: a letter and a symbol on the top,
   and a Greek letter on the front.  For example, the `L' key had an
   `L' and a two-way arrow on the top, and the Greek letter lambda on
   the front.  By pressing this key with the right hand while playing
   an appropriate `chord' with the left hand on the shift keys, you
   could get the following results:

     L
          lowercase l

     shift-L
          uppercase L

     front-L
          lowercase lambda

     front-shift-L
          uppercase lambda

     top-L
          two-way arrow (front and shift are ignored)

   And of course each of these might also be typed with any
   combination of the control, meta, hyper, and super keys.  On this
   keyboard, you could type over 8000 different characters!  This
   allowed the user to type very complicated mathematical text, and
   also to have thousands of single-character commands at his
   disposal.  Many hackers were actually willing to memorize the
   command meanings of that many characters if it reduced typing time
   (this attitude obviously shaped the interface of EMACS).  Other
   hackers, however, thought having that many bucky bits was overkill,
   and objected that such a keyboard can require three or four hands
   to operate.  See {bucky bits}, {cokebottle}, {double bucky},
   {meta bit}, {quadruple bucky}.

   Note: early versions of this entry incorrectly identified the
   space-cadet keyboard with the `Knight keyboard'.  Though both
   were designed by Tom Knight, the latter term was properly applied
   only to a keyboard used for ITS on the PDP-10 and modeled on the
   Stanford keyboard (as described under {bucky bits}).  The true
   space-cadet keyboard evolved from the first Knight keyboard.