On Wed, Mar 1, 2017 at 2:45 AM, Ronald Natalie <ron@ronnatalie.com> wrote:
AIX/370 was a real product. 
​Indeed​ it was.

  All of these AIX versions came from the same source code and used the IBM TCF to allow you to transparently run executables across nodes in the cluster.
​Exactly right.   TCF - Transparent Computing Facility -- No mean trick... ​you can mix PS/2 and 370 in the cluster, so root on desk allowed me root on the mainframe too.   What was cool was that the TCF will look at the executable and find the proper CPU.   The big mistake was that that node id was stored in a single 32 bit word and assigned per bit, which was a scaling issues.

I was at Locus Computing Corp (aka LCC or just "Locus"), who developed AIX for IBM under contract and TCF was part of it.  The direct result of the The LOCUS Distributed System Architecture from UCLA.  The book actually describes much of the AIX/370 work, but starts with the original UCLA work.  I did not work on the IBM project, although a number of my peers did.  I was higher to help developed TNC - Transparent Network Computing, which is was used in Intel's Paragon and DEC's TruClusters and a never shipped HP Cluster Product. Many of the same ideas but we wanted a separate team that never saw the IBM code so there could never be any concern about ownership.  The architects like me and Roman, were allowed to talk to the AIX architects, such as Bruce; but we keep separate development environments at separate sites.    After the IBM work ended, all of the Locus  distributed system folks the struct around went to work on TNC and the technology go sold off and licensed.   What was interesting is that TNC was open'ed sourced after the Compaq/HP mergers and put into Linux but I've forgotten the URL (I'll search and follow up).

It's a real shame it never went anywhere.   It was a very, very cool.

     The only AIX that didn’t play was the completely independent (and in my opinion somewhat brain damaged) IBM/RT UNIX.    If there was a TCF-based RT kernel, I never saw it, even inside the IBM labs.
That was IBM politics.   LCC has the contract for the original AIX port to the 370.   When the RT was developed, the Austin team was ramped up.   One of our members of the TUHS list who is remaining silent I see is not saying why but I know was there ;-) and might  known the actual politics, I never did.   But when the AIX/RT port was forked, they started with AIX/370 code base and removed the TCF code.   But LCC still had the AIX/370 contract from Enterprise system group to maintain AIX/370.   And also, Locus had the contract from Entry Systems, who all they wanted TCF.   So AIX/386 and AIX/370 as Ron points out were one code base, one dev team (at LCC in California).

Dan Cross said:  "I had understood was that AIX/370 was actually OSF/1 based"

It maybe that by the end, the user space was based on the OSF/1 user space code.  That was true for HP and DEC also.   But I can definitely state AIX/370 and AIX/386 were one set of source trees and all of was done by Locus Computing Corporation certainly through the mid 1990s.