It was not this configuration, as the 3278's were connected to a 3274 and nobody mentioned a System/1.
I was, perhaps, 16 or 17, so it just could be that the salespeople on the booth were not taking me seriously.
Someone should preserve this software.
That'd be cool.
Amdahl UTS however ended up being supported by another company "UTS Global" (not sure exactly what their relationship with Fujitsu was, possibly Fujitsu may have kept the underlying IP and UTS Global just sub-licensed it.) It appears UTS Global has gone out of business some years back. I think their main customer were certain US telephone companies using certain legacy apps maintained by Telcordia; I think once those companies migrated off those apps their business was gone and they just disappeared.
Fujitsu's mainframe business is still going. Their Japanese mainframe business (which pre-existed the Amdahl purchase) is still alive (although I don't think it is sold outside Japan any more, back in the 80s thru 90s Fujitsu's FACOM mainframes were common in Australia but I'd be surprised if any remain here). In Europe, they own non-IBM-compatible mainframe lines – they bought ICL whose mainframes are still used by UK government, and they bought Siemens' BS2000 mainframe business which is still used in some European countries (especially Germany).
No idea what Fujitsu's attitude to hobbyist use is. I've never heard anything positive about it. (On the other hand, unlike IBM, I've never heard anything negative about it either.)
 To be strictly correct, BS2000 is partially IBM compatible – the original instruction set is based on S/360 but not 100% compatible with it; that original instruction set ended up being emulated on SPARC and later x86; the OS is very different from any IBM operating system.
And, yes, IBM would likely frown on passing out copies of AIX.
Despite Posix compatibility it wasn't very smooth. One infelicity I remember was that merely untarring a tar file took an extremely long time because ownership information had to be gotten from the ID system (RACF?). And it made separate, expensive calls for each file. Perhaps multiple.
Anyway, as far as I can remember it was soon superseded by the Linux subsystem.
You are thinking of the Unix compatibility subsystem of z/OS (formerly known as OS/390, and before that as MVS). That came out around 1993. But prior to that there was a long history of running Unix on IBM (and IBM-compatible) mainframes as an independent operating system. This work at AT&T, I don't even think it was the first port, I think Princeton's port in 1977 was the first .
And then, as well as Princeton's VM/370-based port and AT&T's TSS/370-based port for 5ESS development, Amdahl UTS came out in 1981 (descended from the Princeton port) and IBM/Interactive Systems VM/IX around 1984; then in 1988, the IBM/Locus AIX/370, followed by AIX/390.
(Also some 1980s-era Japanese supercomputers from Hitachi and Fujitsu had a hardware architecture based on IBM mainframes and some of them also ran Unix, although I'm not sure which version.)
> Anyway, as far as I can remember it was soon superseded by the Linux subsystem.
It was never superseded per se, it still exists. But the use cases are different. If you just want a vanilla Unix-like environment on an IBM mainframe, run Linux – which is not a z/OS subsystem, it is separate independent operating system. If you want a Unix application environment which supports deep integration into legacy mainframe applications and subsystems (VSAM, CICS, IMS, ISPF, etc) then that is the use case for the z/OS Unix subsystem.
In the latest release of z/OS, IBM has brought in a third option: zCX . This runs Linux-based Docker containers on a hypervisor inside z/OS. This is positioned for z/OS system administrators to be able to easily deploy and manage Docker containers on the mainframe without learning extensive Linux skills (which managing z/Linux requires), using mainly their existing z/OS skills along with learning a bit about Docker.
You folks have no idea how much fun you missed out on.