[lunarplague]

I wonder the best way to get acquainted with Unix. Anytime I try to look for a good Unix distribution that would work in a VM, I end up having weird quirks (Scroll up being registered as weird keypresses, or CPU Long Mode not enabled).

[laxd]

The OG unices were dead before X86 "long mode". You need that address space? Keypresses seems like something you could find a solution for. As others have mentioned the bsd's are probably the closest that are up to date with our time. For the vintage stuff, you might want qemu to emulate (not virtualize) your platform.

[sbuk]

The closest easily available Unix is FreeBSD or NetBSD from a heritage point of view. In fact, both have a direct line back to the original Berkeley Systems Distribution, which itself is derived from Unix version 5.

[fuzztester]

install it on another partition or on a separate computer if you can. that will work better than on or VM.

[laxd]

More fun on actual hardware, but then there's the hardware support. BSD's may handle it, but better chose the OS before the computer if you like it smooth.

[ersoft]

I've installed Solaris 11.4 on a spare ssd for fun this month. It worked right away.