The UTS project had its origins in work started at Princeton University in 1975 to port UNIX to the IBM VM/370 system. Team members there were Tom Lyon, Joseph Skudlarek, Peter Eichenberger, and Eric Schmidt. Tom Lyon joined Amdahl in 1978, and by 1979 there was a full Version 6 Unix system on the Amdahl 470 being used internally for design automation engineering. In late 1979 this was updated to the more commonly ported Version 7.
In 1980 Amdahl announced support for Unix on the System 470. Five years later, IBM announced its own mainframe Unix, IX/370, as a competitive response to Amdahl.
The commercial versions of UTS were based on UNIX System III and UNIX System V. In 1986, Amdahl announced the first version to run natively on IBM/370-compatible hardware, UTS/580 for its Amdahl 580 series of machines; previous Unix ports always ran as "guests" under the IBM VMhypervisor. Version 4.5 was based on Unix System V, Release 4 (SVR4).