Didn't Nextstep support x86 long before MacOS X was a thing? I assumed that they always had it compilable on x86 long before the switch (since Rhapsody supported it). I guess the user space stuff might have been trickier but probably not the kernel itself and surrounding components.
Yeah but from what I read from the Quora answer, it sounds like JK did it from scratch? I could be wrong though. I just wonder how much effort is supposed to be put into such a project.
Likely a few foundational technologies that have had significant improvements/reimplementations from Rhapsody like the scheduler/threading infrastructure, memory management, Quartz, Carbon, Quartz.
