​Since a number of the UNIX folks (​tjk, wnj, myself to name three) were old MTS and TSS hackers, a couple of us were always fascinated with this port but I never knew much about it.   As I've said before, fsck was modeled about a program that was originally for TSS and MTS.    There were definite lesson's learned from those systems by some of us when we came to UNIX and I think when some of the TSS folks in NY left CMU or UMich they took some UNIX lessons with them.

Anyway in reading that paper,  I've wondered how much help the TSS group in NY gave the AT&T team and who @ IBM it was.   If I had a to bet, Dean Hiller had to be mixed up in it.  Dean was Mr. TSS and had been my boss at CMU computer center.   I remember showing Dean UNIX running on 11/34 @ EE and he being pretty impressed at how much we could do on such a small system. 

As for other 370 ports, IIRC Tom Lyons started a 370 port at Princeton and finished it at Amdahl.   But I think that was using VM, although it may have had the access to the BTL compiler to start.

When I was at Locus, where we did the AIX/370 and AIX/386 stuff Ron mentions we started over.  Charlie can correct me, but IIRC the compiler was IBM's and as Ron said, AIX/370 too lived as a VM 'service.'  I think I have mention on this list previously, it was targeted for the IBM University customers and was not marketed widely; which was a darned shame because it was a excellent product (and TCF was ahead of its time).    Some one on this lost mentioned needing tons of floppies to install AIX/386 which is was so wrong.   You needed only one, if you had another system (386 or 370 on the network), you just booted the new 'node' and let TCF take over.  You 'joined' the cluster, disk replication would start to fill your disk in. It was extremely fast and easy.  Oh yes - AIX/TCF supported mixed instruction sets between the 370 and x86! (TCF looked for the proper node that had the correct HW provisioning to execute any specific process).  We used to show it off at trade shows, including migrating people's vi sessions 'around' the world when we had a cluster that spanned different physical sites [great fun].    Interesting security flaw -- root on any node in the cluster (like a local 386 node) was the same as root on the 370 nodes.