Space-cadet, Lisp Machine Keyboards

By Xah Lee. Date: . Last updated: .

The Knight Keyboard

One of the first Lisp Machine keyboard, called Knight keyboard.

Novena  Knight keyboard 16277937833-s
Knight keyboard with Novena laptop, 2015. 2592×1944 〔photo by MMcM. Image source https://www.flickr.com/photos/35596940@N00/16277937833, ©
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Knight keyboard 〔image source Knight (TK) keyboard At http://world.std.com/~jdostale/kbd/Knight.html

The Knight keyboard is designed by Tom Knight, was used with the MIT-AI lab's bitmapped display system. It was a precursor to the space-cadet keyboard.

Tom Knight is an American synthetic biologist and computer engineer, who was formerly a senior research scientist at the MIT Computer Science and Artificial Intelligence Laboratory, a part of the MIT School of Engineering.

In 1967 Knight wrote the original kernel for the ITS operating system, that ran on PDP-6 and PDP-10 computers.

In 1968, Knight designed and supervised the construction of the first PDP-10 ARPANET interfaces with Bob Metcalfe.

In 1972, Knight designed one of the first semiconductor memory-based bitmap displays…

In 1974, Knight designed and implemented the prototype version of the MIT Lisp Machine processor…

Wikipedia Tom Knight (scientist)

Space-cadet Keyboard

This is the famous Space-cadet Keyboard.

Space-Cadet keyboard 2
Space-cadet Keyboard

For detail and much more photos, see:

Symbolics Keyboard PN 364000

This model comes after the Space-cadet keyboard.

Symbolics keyboard
Symbolics Keyboard PN 364000. (Photo by webwit At http://deskthority.net/viewtopic.php?p=23509. Used with permission.)

Symbolics keyboard PN 365407 Rev C

This model comes after the PN 364000, and is compatible to it.

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Symbolics's Lisp Machine keyboard PN 365407 Rev C. (Photo by Joey Devilla. Used with permission.)
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Left side.

Rub Out key

2017-05-18 ScottBurson wrote

On an ASR33 Teletype, backspace simply moved the carriage one character position to the left.

Rubout was a different concept entirely. The ASR33 had a paper tape punch and reader. The Rubout character was 0x7F, i.e., it had all bits set. So, to “rub out” an erroneous character from the paper tape, you could back the tape up in the punch to the desired character (by pressing a button on the punch; there was no character that invoked this function) and hit Rubout; this would punch the tape at all seven holes, changing whatever character had been there to a Rubout. (The software ignored Rubout characters on input.)

When the world moved on from Teletypes, it was natural for people to want a single keystroke that meant “delete the previous input character”. But there was evidently some divergence of opinion in the industry as to whether that should be Backspace or Rubout — notwithstanding that the ASR33's concept of Rubout didn't really map at all onto the new hardware.

[2017-05-19 from https://news.ycombinator.com/item?id=14367207]

2017-05-18 kps wrote:

notwithstanding that the ASR33's concept of Rubout didn't
really map at all onto the new hardware.

If you are working with paper tape, Rubout (DEL in ASCII parlance), like every other code, advances the tape when punched. So, if the tape is a stream of characters, DEL erases the one under the cursor and leaves the cursor on the character formerly to the right. That is, Rubout/DEL is defined as a ‘forward delete’ operation, and that's something that remains useful. That leaves Backspace as the natural choice for entering ‘backward delete’ on a keyboard, at least after 1979 when you have the ANSI X3.64 escape sequences for explicitly nondestructive cursor keys. I think there's a reasonable argument for Backspace being nondestructive for overstrike effects (accents, underlining, APL, etc.), especially when received by a terminal, but I know none for changing the meaning of DEL.

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Right side. Note the dedicated parenthesis keys.

Hacker Lore Keyboards

  1. History of Emacs and vi Keys
  2. Space-cadet, Lisp Machine Keyboards
  3. Space-cadet Keyboard
  4. How to Create APL or Math Symbols Keyboard Layout
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