Shows Elite running on a 2MHz 6502.
Full comment
We were talking about "the 70s and 80s", not 01959. My point about APT is that a "beefy machine" in 01959 was the embedded controller in your keyboard by 01983; it wasn't a beefy machine any more. The PDP-8 was indeed pretty common for CNC control in the late 01960s, and it could run about 333000 12-bit instructions per second, which is about half as fast as the original IBM PC. So, yeah, a machine like that was exactly a home PC by the mid-80s. For real-time control of the 3-D printer, you can get by with less. There were three big problems for manipulating 3-D models for home hobbyists in the 70s and 80s. One was computational speed: for games, you need to render the 3-D graphics fast enough to provide an illusion of immersion, and with a few hundred thousand instructions per second (and no multiplier) you were limited to a handful of polygons. Like, typically about 20. See the Apple ][ FS1 flight simulator this video , the 01983 Star wars arcade game (at 2:02), Battlezone (2:14), and Ian Bell and David Braban's Elite from 01984, which was successfully ported from the 2MHz 6502 in the BBC Micro (2:53, but also most of the rest of the hour of the video) to the Z80-based ZX Spectrum (3.5MHz but noticeably slower than the 6502; see link ). For producing G-code, though, you don't need to be able to handle all the 3-D geometry in 50 milliseconds. You just need to be able to handle it overnight. That's a million times longer, so you can do a million times as much computation on th