Amdahl UTS

UTS Release 4.5 supports the following S/390 model processors and their successors:

• Amdahl 5990, 5995A, 5995M series of ECL processors
• Amdahl Millennium Global Server series of CMOS processors
• Fujitsu Global Server
• IBM ES/9000/9021 series of ECL processors
• IBM G4, G5 & G6 Servers (the 9672 R and X series of CMOS processors)

The UTS project had its origins in work started at Princeton University in 1975[https://www.tuhs.org/Archive/Distributions/IBM/370/toms_blog_pt1.html The Roots of UNIX for the IBM Mainframe], Tom Lyon's Personal Blog. 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.{{cite news | url=https://archive.org/stream/byte-magazine-1983-10/1983_10_BYTE_08-10_UNIX#page/n133/mode/2up | title=The Unix Tutorial / Part 3: Unix in the Microcomputer Marketplace | work=BYTE | date=October 1983 | access-date=30 January 2015 | author=Fiedler, Ryan | pages=132}} The UTS (Universal Timesharing System) also ran on National Advanced Systems mainframes. Five years later, IBM announced its own mainframe Unix, IX/370, as a competitive response to Amdahl.{{cite news |newspaper=Computerworld |date=18 February 1985 |title=Users: new life for VM |page=11 |url=https://books.google.com/books?id=iwX8vVdMAckC&pg=PA11 |first=John |last=Gallant}} The Intel 80386 design team ported UTS to test the processor's viability to run Unix.{{Cite interview |last=Crawford |first=John |interviewer=Jim Jarrett |title=Intel 386 Microprocessor Design and Development Oral History Panel |last2=Hill |first2=Gene |last3=Leukhardt |first3=Jill |last4=Prak |first4=Jan Willem |last5=Slager |first5=Jim |url=https://archive.computerhistory.org/resources/access/text/2015/06/102702019-05-01-acc.pdf |access-date=2025-05-15 |publisher=Computer History Museum |place=Mountain View, California |language=en-US}}

The commercial versions of UTS were based on UNIX System III and UNIX System V. In 1986, Amdahl announced the first version to run bare metal on IBM/370-compatible hardware, UTS/580 for the Amdahl 580 series of machines; previous Unix ports always ran as "guests" under the IBM VM hypervisor. Performance improved by 25% without VM, the company said.{{cite news |first=Jeffry |last=Beeler |newspaper=Computerworld |date=27 January 1986 |title=Amdahl broadens Unix-based UTS line |url=https://books.google.com/books?id=33QfOHT69aMC&pg=PA13}} Version 4.5 was based on Unix System V, Release 4 (SVR4).

In 1987 Amdahl announced that it ended Aspen, a project started seven years earlier to create a proprietary operating system, and instead would focus on UTS.{{Cite magazine |last=Leong |first=Kathy Chin |date=1987-11-02 |title=Amdahl kills Aspen plan, favors Unix |url=https://books.google.com/books?id=mUSIMiurpfYC&pg=PP1 |access-date=2025-06-08 |magazine=Computerworld |pages=1,10 |volume=XXI |issue=44}}

• Linux on IBM Z
• OpenSolaris for System z
• UNIX System Services in OS/390 and its successors
• UNIX-RT
• RTLinux

{{Reflist}}

• [https://web.archive.org/web/20080422064423/http://www.utsglobal.com/Unix.html UTS Global home page (archived page at Archive.org, April 2008)]

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Category:Unix variants

Category:1981 software

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