[dekhn]

Likely any early implementation of ML would have been on a mainframe or minicomputer, not a 6502. A mainframe/minicomputer would have had oodles of storage (both durable and RAM), as well as a compiler for a high level language (which fits what I can see in https://smlfamily.github.io/history/ML2015-talk.pdf and other locations).

[noelwelsh]

So I've been mildly nerd sniped. It looks like the first target was a PDP-10 [1]. It ran Stanford Lisp used by the "DEC 10" implementation of ML. The architecture is pretty unusual by modern standards, but it doesn't look to be that powerful and seems to top out at around 1MB of RAM. Next up we have a VAX [2] implementation. It's not clear which specific system it was originally developed for, but we're talking early 80s so it probably wasn't much more powerful than the PDP-10. Either way, I think a maxed Apple IIGS with a hefty 8MB of RAM and perhaps overclocked to 14MHz is more than enough raw power to handle ML. Unfortunately I haven't been sufficiently nerd sniped to actually implement this. I leave that as an exercise for the reader ;-)

[1]: https://en.wikipedia.org/wiki/PDP-10

[2]: https://en.wikipedia.org/wiki/VAX

[dekhn]

an enormous amount of software was developed on the PDP-10 and PDP-11 and later VAX systems that could not have been done on microcomputers in the day. You can't just compare raw RAM and clock rates, the PDPs were set up for multi-user productivity on complex problems and had a wide range of system software to enable building and deploying advanced software.