[TUHS] UNIX on (not quite bare) System/370

The October 1984 BSTJ article by Felton, Miller and Milner https://www.bell-labs.com/usr/dmr/www/otherports/ibm.pdf Describes an AT&T port of UNIX to System/370 using TSS/370 underpinnings as the "Resident System Supervisor" and used as the 5ESS switching system development environment. I also found mention at http://www.columbia.edu/~rh120/ch106.x09 chapter 9 of http://www.columbia.edu/~rh120/ with footnote 96: Ian Johnstone, who had been the tutor at University of New South Wales working with Professor John Lions, was one of the researchers invited to Bell Labs. He managed the completion at AT&T Bell Labs of the port of Unix to the IBM 370 computer. See "Unix on Big Iron" by Ian Johnstone and Steve Rosenthal, UNIX Review, October, 1984, p. 26. Johnstone also led the group that did the port to the AT&T 2B20A multiprocessor system. I found https://ia902801.us.archive.org/3/items/Unix_Review_1984_Oct.pdf/Unix_Revie… "BIG UNIX: The Whys and Wherefores" (pdf p.24), which only offers rationale. Also: "IBM's own involvement in Unix can be dated to 1979, when it assisted Bell Labs in doing its own Unix port to the 370 (to be used as a build host for the 5ESS switch's software). In the process, IBM made modifications to the TSS/370 hypervisor to better support Unix.[12]" at https://en.wikipedia.org/wiki/IBM_AIX#cite_ref-att-s370-unix_12-0 Is there any other surviving documentation about the system? Any recall of what branch of AT&T UNIX it was based on? Thanks! Phil