It was linked a little up thread, but since you’re (probably) referring to the “Space-cadet” keyboard, it was seven.
Technically, they drew a distinction between the “shift” keys (of which there were three), and the other modifiers (four).
In modern times (or for Linux at least), Meta has essentially coalesced with Alt, so the modifiers we’ve retained are Control, Alt, and Super (Windows), with only “Hyper” having been lost along the way.
The remaining two shifts (also lost to time) were “Top” (symbols) and “Front” (Greek), with the Greek supporting combining with shift (there’s a table on that Wiki page).
Here’s the summary for the wikipedia article you mentioned in your comment:
The space-cadet keyboard is a keyboard designed by John L. Kulp in 1978and used on Lisp machines at Massachusetts Institute of Technology (MIT), which inspired several still-current jargon terms in the field of computer science and influenced the design of Emacs. It was inspired by the Knight keyboard, which was developed for the Knight TV system, used with MIT's Incompatible Timesharing System.
It was linked a little up thread, but since you’re (probably) referring to the “Space-cadet” keyboard, it was seven.
Technically, they drew a distinction between the “shift” keys (of which there were three), and the other modifiers (four).
In modern times (or for Linux at least), Meta has essentially coalesced with Alt, so the modifiers we’ve retained are Control, Alt, and Super (Windows), with only “Hyper” having been lost along the way.
The remaining two shifts (also lost to time) were “Top” (symbols) and “Front” (Greek), with the Greek supporting combining with shift (there’s a table on that Wiki page).
Here’s the summary for the wikipedia article you mentioned in your comment:
The space-cadet keyboard is a keyboard designed by John L. Kulp in 1978 and used on Lisp machines at Massachusetts Institute of Technology (MIT), which inspired several still-current jargon terms in the field of computer science and influenced the design of Emacs. It was inspired by the Knight keyboard, which was developed for the Knight TV system, used with MIT's Incompatible Timesharing System.article | about
I believe this same keyboard is why certain Vim keybindings are the way they are, like the arrow keys were on hjkl,