The only thing I’d add is that the emulator has since been ported to Linux and it’s perfectly possible to emulate a lisp machine on a modern Linux distribution

The only thing I’d add is that the emulator has since been ported to Linux and it’s perfectly possible to emulate a lisp machine on a modern Linux distribution (you can find instructions online for Ubuntu, but it should be fairly easy to figure out how to adapt them for an arbitrary distribution). However, the IP issues make running such a system a somewhat grey area.