Specifically:
- The ADM-3A[1] (mid ’70s) had Ctrl above Shift and apparently no Caps Lock.
- The Lisp machines[2,3] (late ’70s to mid ’80s) had Ctrl below Shift and Rub Out above Shift.
- The IBM 3270 series (from the early ’70s onwards) terminals (those that were capable of lower-case input) are pictured in Wikipedia[4] with a Caps Lock above Shift and no Ctrl (which agrees with their input model) but I get the impression that IBM produced a bajillion keyboard variations for these.
- The Model F variants for the XT and the AT (first half of the ’80s) has Ctrl above left Shift, Alt below it, and Caps Lock below right Shift[5], as well as 5×2 function keys on the left and no separate arrow keys; the later Model M variants (1985 onwards) use the modern layout; yet once again, looking at the separate pages for the Model F and the Model M, I get the impression that IBM simply produced a bajillion different versions of them.
- The ANSI standard to which the appellation of “ANSI layout” refers is ANSI X3.154-1988, so presumably things had settled by then?..
[1] https://commons.wikimedia.org/wiki/File:Adm3aimage.jpg
[2] https://commons.wikimedia.org/wiki/File:Space-cadet.jpg
[3] https://commons.wikimedia.org/wiki/File:Symbolics-keyboard.j...
[4] https://commons.wikimedia.org/wiki/File:IBM-3279.jpg
[5] https://en.wikipedia.org/wiki/IBM_PC_keyboard#Keyboard_layou...
To me, it makes no sense to me to make less-reachable the key that gets used the most. To reach the current CTRL key, I have to bend and twist my hand so that the pinky finger can reach the CTRL key. I never use the CAPS LOCK key, which is sitting under and adjacent to where the pinky rests.