Quote:

You know, I hadn't considered the need for an MMU.
And my primary experience with UNIX (or UNIX-like) OS' (outside of Microware's OS9) was Xenix.
That doesn't require an MMU (although it could benefit from one), and its damned slow on a 6-8 MHz 68000.
Which, come to think of it, was one of the reasons we were working with OS9.
That and the fact that the OS required reentrant code, making it pretty efficient with memory.
After all, I don't think anyone remembers how damned high memory prices used to be.
Every 512K of memory cost our users as much as the average price for a 8 bit PC.
It was not cool.
These days, code reentrancy is not a particularly useful feature, as the utility of multiple processes using a single module (outside of memory savings) isn't that important.
But, two other features that OS highlighted, position independent code, a microkernel core...still pretty useful stuff.

BTW - You CAN create a Linux distro without an MMU, but some commands get left out (as they just won't work).
But, the kernel itself can be ported, its been done.

Which IS more than you can say for early X86, which can't support anything much more complicated than CP/M or DOS.
Even Windows didn't run well until you bumped your specs up to an i'386 or better.

So again, no, the i286 in no way obsoleted the 68K series.