wikipedia article

[John Nemeth]

On Nov 1,  6:11pm, "Ted Mittelstaedt" wrote:
} 
} Prior to the release of the 80386 the Intel processors didn't have
} memory protection which was a requirement of any processor running
} the BSD kernel.

     This is not entirely true.  The 80286 had memory protection.
However, its memory protection was completely based on segments (i.e.
it could not do paging).  Also, it was only a 16 bit processor.  These
two items combined to make it very difficult to run a modern Unix-like
system.  However, it did run Xenix as well as various other systems.
The 80386 was the first processor with paging (which all modern virtual
memory systems are based around) and 32 bits.

}-- End of excerpt from "Ted Mittelstaedt"