Where did all these Unix's come from?

[Tim W Smith]

Could someone clarify what the history of V.3 on the 386 is?
I know about the early stuff (AT&T arranges with Intel for V.3
on the 386.  Intel in turn turns to Interactive for large parts
of this project).

I know about AT&T, Microsoft, and Interactive doing stuff for
Xenix compatibility, with AT&T and Microsoft dealing with 386
Xenix compatibility, and Microsoft and Interactive dealing with
286 binary compatibility.

What happened after this?  How do AT&T, Interactive, Intel, SCO,
Microsoft, ESIX, Microport, and whomever I am missing fit in now?
Are they all pretty much the same kernel with the various vendors
distinguishing themselves via what drivers they support and what
utilities or extras they've added?

How do new versions propogate.  For example, if AT&T came out with
System V.5 on the 3B2, which vendors would get the 3B2 sources and
port these to the 386, and which would wait for someone else to do
the port and get it from them?

						Tim Smith