Gothenburg Universities Computer Centre (in Sweden) developed a timesharing system for IBM mainframes, known as GUTS (variously expanded either as ''Gothenburg University Timesharing System'', or as ''Gothenburg Universities Terminal System''). It appears some other universities adopted it; one source mentions its use at University College London in the 1970s; another mentions its use at Trinity College Dublin, on an IBM 360/44 which was the first timesharing system in Ireland, as a replacement for IBM RAX and ITF (Interactive Terminal Facility, a predecessor to TSO).

Westgard and Groth's 1981 paper, "Design and evaluation of statistical control procedures: applications of a computer 'quality control simulator' program" describes chemistry simulation software written in "FORTRAN IV for an IBM 370/158 computer run under OS/MVT and the Gothenburg University Terminal System", providing a citation to "Gothenburg University terminal system. TS-GUTS reference manual. Gothenburg University Data Center, Gothenburg, Sweden, 1980".

From what I understand, rather than an operating system in its own right, it was a timesharing subsystem for MVS (and its predecessors such as OS/360 MVT), an alternative to TSO.

The Kermit Software Source Code Archive preserves "Kermit/GUTS", "Kermit for the Gothenburg University Timesharing System (GUTS)", version 1.0, dated 1985-04-05. It is noted as being for the IBM 370, written in BAL (IBM Basic Assembly Language), and the OS name is given as "MVS/GUTS". It preserves the source code and some associated documentation and emails. One particularly interesting file it preserves, is what appears to be an example of its procedure language. The help message embedded in that procedure contains an interesting tidbit about the nature of GUTS, that it had two different types of files, OS and GUTS:

 %WRLINE            KERMIT-GUTS (which is the name of the GUTS version  00032290
 %WRLINE            of KERMIT) can only send and receive OS-files.      00032300
 %WRLINE            If you want to send a GUTS file you will have to    00032310
 %WRLINE            copy if first to a OS-file. You can do that with    00032320
 %WRLINE            the /TSOS procedure. You can use the /OSTS procedure00032330
 %WRLINE            to copy a OS file to a GUTS file.                   00032340

Another source I've stumbled across, in the IAEA International Nuclear Information System (INIS), is a 1986 progress report (catalog entry, PDF on the "NAMMU-HYPAC" system for nuclear waste hydrology, then under development at Stockholm University Computer Center. Appendix 6 (page 34 onwards) also provides some interesting information on GUTS:

HYPAC... is implemented on a MVS operating system together with GUTS (Gothenburg Universities Terminal System).

GUTS provides among other things a text editor, a file system (the files stored there are called GUTS-files as opposed to ordinary MVS-files which are called OS-files ), a possibility to submit jobs to MVS and to retrieve job output to GUTS files, tools for conversion of GUTS-files to OS-files and back and also a possibility to run programs interactively.

To use the HYPAC-NAMMU package at QZs Amdahl computer you should have a basic knowledge of

  • JCL (Job Control Language) for the MVS operating system
  • GUTS (Gothenburg Universities Terminal System)
  • FEMGEN (mesh generator program)

You should also have access to various GUTS procedures and JCL-decks

Page 37 (Appendix 7) of the same report gives a couple of examples of GUTS commands. Firstly, to print the contents of an MVS/OS file (actually a PDS member):


And, to convert an OS/MVS file to a GUTS file:

OSTS 'SD.ABC123S.COIBAN(abcd)',gutsfilename

An interesting message sent to IBM-MAIN mailing list in July 1999, by Martin Leist, Technical Analyst, Norfolk County Council, UK:

All this talk of ROSCOEand COM-PLETE etc, but is anyone else out
there still using GUTS (Gothenburg University Timesharing System) ?
It was quite popular over here in the UK during the 1980's as it ran on
VS1 and MVS as well as the earlier incarnations of those systems.
We are now the only UK site (we think) still actively running the
system and have to do our own (source) modifications at each new
level of OS/390. GUTS is *very* TSO compatible, so much that you
can actually run ISPF under it, although that defeats the object as
GUTS uses one address space for all its editing and file
management, only using other address spaces when invoking an
external program, those being shared among all users. I think the
system was used by some parts of the US IRS but have no idea if its
still used.

One of the active (UK) developers later went on to IBM and used
some of the techniques that had been used in GUTS to improve the
performance of CICS. The "end" of GUTS was signalled when
Gothenburg University moved away from a mainframe based system.

Still, in terms of actual technical information, all I have been able to find is these few tidbits. Is anyone aware of any further sources?

  • 2
    @TomasBy thanks. What I am keenest on finding is technical details – although information on who used it is also interesting. parlament.gv.at/PAKT/VHG/XVI/III/III_00121/imfname_553284.pdf is 1984 report by the Austrian Government, on computer hardware/software use in Austria. PDF page 291 mentions GUTS was used by University of Linz Oct 23, 2022 at 9:31

2 Answers 2


I know for certain that Trinity College Dublin used GUTS on their IBM 360/44. I studied there from 1975-1979 and personally used it. It was phased out around 1978-1979 when they got a new DECSystem 20. We undergraduates used it to edit our programs. We used the PL/C compiler. I remember finding a bug in GUTS where I mistakenly entered a negative line number in an edit and crashed the whole mainframe!


Linz (Austria) University used GUTS in the early 1980s.

  • 1
    That's useful information. Could you elaborate? Given how little we have right now, anecdotes (or anything else you have) would be helpful. You can edit your answer to add more.
    – wizzwizz4
    Oct 27, 2022 at 18:24
  • If you've lost access to the account you used to post this answer, you could make a new one and request them merged using the [contact] form. (You don't have to, though; so long as you don't vote on your own stuff, using multiple accounts is allowed.)
    – wizzwizz4
    Oct 27, 2022 at 18:25

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .