so we can go really off topic, you can get close to there in the Raspberry PI realm since it goes back to BSD based.That makes me wonder if there is any possibility at all of obtaining a copy of the Intel port of NeXTstep, and making it run on modern PC hardware. It's probably a very long shot, due to hardware having evolved so far since then, and there probably being no drivers for NeXTstep to support most modern hardware.
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