I used this keyboard, as well as the ones for MIT-AI's graphics terminals from which it was inspired, and a 2nd generation of those (long story), at the same ti

I used this keyboard, as well as the ones for MIT-AI's graphics terminals from which it was inspired, and a 2nd generation of those (long story), at the same time I was using "standard" keyboards including the IBM PC's, and if you have the ability to ignore keys you don't need, you can focus on the home keys and Control and Meta (and ideally use the key left of A as rubout/backspace; it not being Caps Lock is not really a problem for coders). The big issue is that the IBM layout is Ctrl-Alt, whereas the Lisp Machine was [too many other "bucky bits"]-Meta-Ctrl. Since I learned EMACS with the latter layout, for many years I just remapped those keys on other systems.