Using both the CTRL and META keys. “The command to burn all LEDs is double bucky F.”

This term originated on the Stanford extended-ASCII keyboard, and was later taken up by users of the space-cadet keyboard at MIT. A typical MIT comment was that the Stanford bucky bits (control and meta shifting keys) were nice, but there weren't enough of them; you could type only 512 different characters on a Stanford keyboard. An obvious way to address this was simply to add more shifting keys, and this was eventually done; but a keyboard with that many shifting keys is hard on touch-typists, who don't like to move their hands away from the home position on the keyboard. It was half-seriously suggested that the extra shifting keys be implemented as pedals; typing on such a keyboard would be very much like playing a full pipe organ. This idea is mentioned in a parody of a very fine song by Jeffrey Moss called Rubber Duckie, which was published in The Sesame Street Songbook (Simon and Schuster 1971, ISBN 0-671-21036-X). These lyrics were written on May 27, 1978, in celebration of the Stanford keyboard:

[This, by the way, is an excellent example of computer filk —ESR] See also meta bit, cokebottle, and quadruple bucky.