Is it possible a unix or linux for 80286 machine (or any machine without memory page mechanism)

Is it possible to have a Unix OS for 80286 machine (or any machine without paged memory mechanism but with segmented memory)?

80286 is a CPU without TLB, Page tables; only with segmented virtual memory and segmented protection of memory.

Is it possible to have a Linux on such machine?

UPD: the processor is very old, so I only ask about h开发者_运维问答istoric versions, not the ultra modern linux 2.6.42.11 or Solaris 13 or FreeBSD 10 or ...

The Linux/Microcontroller project (µClinux) is a port of Linux to systems without a Memory Management Unit (MMU).

There's the older ELKS project too.

However, due to the lack of MMU, many standard UNIX features (like fork and mmap) are not supported.

Today's Linux will only compile for a 486 or higher. So it's unlikely. I do remember 386s being somewhat supported in the 2.4.x era, but I don't remember anything about 286s.

User Zack says that Xenix (based on original UNIX) was capable of running on 80286:

There certainly were Unixes that ran on the 80286 -- Xenix comes to mind -- but I don't know if there's anything that implements what you would call a modern programming environment.

I'd checked, the Xenix FAQ http://www.uni-giessen.de/faq/archiv/sco-xenix/msg00000.html says

QA1 ... The PC/AT offered hardware memory protection, and SCO Xenix/286 took advantage of it.

So it was a PC/AT (80286) unix, which did used a memory protection using segmented memory (unlike modern unixes which use page based memory protection).

According to http://www.deinmeister.de/x86modes.htm 80286 have memory protection only in terms of segments, not a pages (pages was added in 80386).

Not sure how interested you are in the programming of it (if at all), but I was playing around with OpenCourseWare class from MIT awhile ago and they had a version of Minix they ported to x86 (not sure if it was just for 386+ or not and can't seem to find the link anymore). Anyway, if you're interested you can check it out here: MIT OpenCourseWare Operating System Engineering

I doubt so. From the very beginning, Linux was designed for the 386, using 386-specific features. MINIX, on the other hand, predates the 386 (and 286), so there should be a 286-compatible version out there.