Mei culpa/my apologies -- I left out the ISC part of the story and I was not trying to rewrite history in any way.   In fact, to the rest of the list, ISC did the first 386 port of UNIX - which for UNIX history is extremely significant.  One of my favorite pieces of salesmanship - Heinz, Peter, and Phil Shevrin managed to convince both AT&T and Intel to separately pay for the 386 port (and I thought IBM was in that mix somehow too).  Then ISC brought it out as a separate product that I think Sun ended up with at some later time yet.  If I recall, ISC did the original work on the RT (which redates the RS/6000) and the ISC folks had their own product for VM before IBM released AIX/370 as a product.   Heinz and Charlie would know more details on those ports.

That said, the comment that I was originally replying to was about IBM getting interested in BSD UNIX and my point was simply, AIX/370 was BSD-based and was shipping as an IBM product years before Linus even started working on what would become Linux for his 386 based machine; much less any attempt to get it running on the 370.

Also, if we are to be complete.  Tom Lyons did the original 360/370 C/UNIX work at Princeton & AT&T long before any of that, starting in the mid-1970s but I'll let Tom fill you in there.