The point is that PS/2 keyboards were not necessarily
attached to
 PS/2s. They became an extremely widespread industry standard, even
 beyond PC compatibles - e.g. later Acorn ARM RISC machines such as the
 RiscPC and A4000 and A7000 used them, too, as did some PReP Mac
 clones. 
    - Newer SGI machines (Indy, Octane, etc)
    - PA-RISC machines (712/80, 9000/D210 - these I have and can attest)
    - Most things that use external keyboards made after 1990
    - (ops, I forgot other options)