View source for Michigan Terminal System

{{Short description|Mainframe operating system}}
{{Infobox OS
| name                   = Michigan Terminal System (MTS)
| logo                   =
| screenshot             = [[File:MTS signon screenshot.png|220px]]
| caption                = The MTS welcome screen as seen through a [[IBM 3270|3270]] [[terminal emulator]].
| developer              = [[University of Michigan]] and [[#MTS Consortium|7 other universities]] in the US, Canada, and the UK
| family                 =
| working_state          = Historic
| source_model           =
| released               = {{Start date and age|1967}}
| latest_release_version = 6.0 (final)
| latest_release_date    = {{Start date and age|1988}}
| latest_test_version    =
| latest_test_date       =
| marketing_target       =
| programmed_in          = various languages, mostly 360/370 [[Assembly language]]
| prog_language          = Assembly, FORTRAN, PL/I, PLUS, ALGOL W, Pascal, C, LISP, SNOBOL4, COBOL, PL360, MAD/I, GOM (Good Old Mad), APL, and [[#Programming languages available under MTS|many more]]
| language               = [[English language|English]]
| updatemodel            =
| package_manager        =
| supported_platforms    = [[IBM System/360|IBM S/360-67, IBM S/370 and successors]]
| kernel_type            =
| ui                     = [[Command-line interface]]
| license                = Free ([https://creativecommons.org/licenses/by/3.0/ CC BY 3.0])
| preceded by            = [[University of Michigan Executive System]]
| succeeded by           = 
| website                = [https://archive.org/details/michigan-terminal-system-distribution-documentation-and-files archive.org]
}}
{{History of IBM mainframe operating systems|misc}}
The '''Michigan Terminal System''' ('''MTS''') is one of the first [[time-sharing]] computer [[operating system]]s.<ref name= Galler-LifeAndWork-IEEE>{{Citation |quote= In late 1968, MTS was the only large-scale timesharing system to be in regular, reliable operation in the US |url= http://muse.jhu.edu/journals/ieee_annals_of_the_history_of_computing/v030/30.1akera.pdf |title= The Life and Work of Bernard A. Galler (1928–2006) |first= Atsushi |last= Akera |journal= Annals of the History of Computing |volume= 30 |number= 1 |date= Jan–Mar 2008 |page= 8 |doi=10.1109/mahc.2008.15|s2cid= 22790110 }}.</ref> Created in 1967 at the [[University of Michigan]] for use on [[IBM System/360|IBM S/360]]-67, S/370 and compatible [[mainframe computer]]s, it was developed and used by a consortium of eight universities in the [[United States]], [[Canada]], and the [[United Kingdom]] over a period of 33 years (1967 to 1999).<ref name= MTSVol1>{{Citation |url= https://deepblue.lib.umich.edu/bitstream/handle/2027.42/79598/MTSVol01-TheMichiganTerminalSystem-Nov1991.pdf?sequence=1&isAllowed=y |title=The Michigan Terminal System |volume=1 |date=November 1991 |publisher=University of Michigan, Information Technology Division, Consulting and Support Services |pages= 9, 13–14 |place= Ann Arbor, Michigan}}.</ref>

==Overview==
The University of Michigan Multiprogramming Supervisor (UMMPS) was initially developed by the staff of the academic computing center at the [[University of Michigan]] for operation of the [[System/360|IBM S/360-67, S/370]] and compatible computers. The software may be described as a [[multiprogramming]], [[multiprocessing]], [[virtual memory]], [[time-sharing]] supervisor that runs multiple resident, [[reentrant (subroutine)|reentrant]] programs. Among these programs is the Michigan Terminal System (MTS) for command interpretation, execution control, file management, and accounting. End-users interact with the computing resources through MTS using terminal, batch, and server oriented facilities.<ref name=MTSVol1/>

The name MTS refers to:
*The UMMPS Job Program with which most end-users interact;
*The software system, including UMMPS, the MTS and other Job Programs, Command Language Subsystems (CLSs), public files (programs), and documentation; and
*The time-sharing service offered at a particular site, including the MTS software system, the hardware used to run MTS, the staff that supported MTS and assisted end-users, and the associated administrative policies and procedures.

MTS was used on a production basis at about 13 sites in the [[United States]], [[Canada]], the [[United Kingdom]], [[Brazil]], and possibly in [[Socialist Federal Republic of Yugoslavia|Yugoslavia]] and at several more sites on a trial or benchmarking basis. MTS was developed and maintained by a core group of eight universities included in the [[#MTS Consortium|MTS Consortium]].

The University of Michigan announced in 1988 that "Reliable MTS service will be provided as long as there are users requiring it ... MTS may be phased out after alternatives are able to meet users' computing requirements".<ref name="itd19881031">{{cite journal |url=https://books.google.com/books?id=WSBVAAAAMAAJ&pg=RA1-PA118 |title=ITD Reaffirms MTS Commitment |journal=U-M Computing News |date=October 1988 |volume=3 |issue=19 |pages=2}}</ref> It ceased operating MTS for end-users on June 30, 1996.<ref>[https://babel.hathitrust.org/cgi/pt?id=mdp.39015040313788;view=1up;seq=95 "MTS Service to End"], ''Information Technology Digest'', Vol. 5, No. 5 (May 12, 1996), p.7</ref> By that time, most services had moved to client/server-based computing systems, typically Unix for servers and various Mac, PC, and Unix flavors for clients. The University of Michigan shut down its MTS system for the last time on May 30, 1997.<ref name=MTSTimeline>[https://babel.hathitrust.org/cgi/pt?id=mdp.39015040313788;view=1up;seq=98 "MTS Timeline"], ''Information Technology Digest'', University of Michigan, pp.10-11, Volume 5, No. 5 (May 13, 1966)</ref>

[[Rensselaer Polytechnic Institute]] (RPI) is believed to be the last site to use MTS in a production environment. RPI retired MTS in June 1999.<ref>[http://www.clock.org/~jss/work/mts/timeline.html "MTS Timeline"], an after the fact one entry addition for 1999 to ''Information Technology Digest'', University of Michigan, Volume 5, No. 5 (May 13, 1966)</ref>

Today, MTS still runs using IBM S/370 emulators such as [[Hercules emulator|Hercules]], Sim390,<ref>[http://www.canpub.com/teammpg/de/sim390/ Sim390], an ESA/390 emulator</ref> and FLEX-ES.<ref>[http://www.funsoft.com/mfos-body.html FLEX-ES], a S/390 and z/Architecture emulator</ref>

==Origins==
In the mid-1960s, the University of Michigan was providing [[batch processing]] services on [[IBM 7090]] hardware under the control of the [[University of Michigan Executive System]] (UMES), but was interested in offering interactive services using [[time-sharing]].<ref name=Topol30Years>[https://babel.hathitrust.org/cgi/pt?id=mdp.39015040313788;view=1up;seq=97 "A History of MTS&mdash;30 Years of Computing Service"], Susan Topol, ''Information Technology Digest'', Volume 5, No. 5 (May 13, 1996), University of Michigan</ref> At that time the work that computers could perform was limited by their small [[computer memory|real memory]] capacity. When IBM introduced its [[System/360]] family of computers in the mid-1960s, it did not provide a solution for this limitation and within IBM there were conflicting views about the importance of and need to support time-sharing.

A paper titled ''Program and Addressing Structure in a Time-Sharing Environment'' by [[Bruce Arden]], [[Bernard Galler]], [[Franklin H. Westervelt|Frank Westervelt]] (all associate directors at UM's academic Computing Center), and Tom O'Brian building upon some basic ideas developed at the Massachusetts Institute of Technology (MIT) was published in January 1966.<ref>[https://dl.acm.org/citation.cfm?doid=321312.321313 "Program and Addressing Structure in a Time-Sharing Environment"], B. W. Arden, B. A. Galler, T. C. O'Brien, F. H. Westervelt, ''Journal of the ACM'', v.13 n.1, p.1-16, Jan. 1966</ref> The paper outlined a [[virtual memory]] architecture using dynamic address translation (DAT) that could be used to implement time-sharing.

After a year of negotiations and design studies, IBM agreed to make a one-of-a-kind version of its S/360-65 mainframe computer with dynamic address translation (DAT) features that would support [[virtual memory]] and accommodate UM's desire to support time-sharing. The computer was dubbed the Model S/360-65M.<ref name=Topol30Years/> The "M" stood for Michigan. But IBM initially decided not to supply a time-sharing operating system for the machine. Meanwhile, a number of other institutions heard about the project, including [[General Motors]], the [[Massachusetts Institute of Technology]]'s (MIT) [[Lincoln Laboratory]], [[Princeton University]], and Carnegie Institute of Technology (later [[Carnegie Mellon University]]). They were all intrigued by the time-sharing idea and expressed interest in ordering the modified IBM S/360 series machines. With this demonstrated interest IBM changed the computer's model number to [[IBM System/360 Model 67|S/360-67]] and made it a supported product.<ref name=Galler-LifeAndWork-IEEE/> With requests for over 100 new model S/360-67s IBM realized there was a market for time-sharing, and agreed to develop a new time-sharing operating system called [[TSS/360]] (TSS stood for Time-sharing System) for delivery at roughly the same time as the first model S/360-67.

While waiting for the Model 65M to arrive, U of M Computing Center personnel were able to perform early time-sharing experiments using an [[IBM System/360 Model 50]] that was funded by the [[Defense Advanced Research Projects Agency|ARPA]] CONCOMP (Conversational Use of Computers) Project.<ref>[https://deepblue.lib.umich.edu/handle/2027.42/8249 ''CONCOMP: Research in Conversational Use of Computers: Final Report''], Westervelt, F. H., University of Michigan Computing Center, 1970</ref> The time-sharing experiment began as a "half-page of code written out on a kitchen table" combined with a small multi-programming system, LLMPS from MIT's [[Lincoln Laboratory]],<ref name=Galler-LifeAndWork-IEEE/> which was modified and became the U of M Multi-Programming Supervisor (UMMPS) which in turn ran the MTS job program. This earliest incarnation of MTS was intended as a throw-away system used to gain experience with the new IBM S/360 hardware and which would be discarded when IBM's [[TSS/360]] operating system became available.

Development of TSS took longer than anticipated, its delivery date was delayed, and it was not yet available when the S/360-67 (serial number 2) arrived at the Computing Center in January 1967.<ref>[https://www.multicians.org/thvv/360-67.html ''The IBM 360/67 and CP/CMS''], Tom Van Vleck</ref> At this time UM had to decide whether to return the Model 67 and select another mainframe or to develop MTS as an interim system for use until TSS was ready. The decision was to continue development of MTS and the staff moved their initial development work from the Model 50 to the Model 67. TSS development was eventually canceled by IBM, then reinstated, and then canceled again. But by this time UM liked the system they had developed, it was no longer considered interim, and MTS would be used at U of M and other sites for 33 years.

==MTS Consortium==
MTS was developed, maintained, and used by a consortium of eight universities in the US, Canada, and the United Kingdom:<ref name=MTSVol1/><ref name=WhyMTSSites>[http://archive.michigan-terminal-system.org/discussions/how-did-sites-learn-about-and-make-the-decision-to-use-mts "How did sites learn about and make the decision to use MTS?"], an item in the discussion section of the Michigan Terminal System Archive</ref>

*[[University of Michigan]] (U of M), 1967 to 1997,<ref>{{cite web|url=http://www.clock.org/~jss/work/mts/no-more-mts.html|title=Josh Simon's Work Information: MTS Retired|work=clock.org}}</ref> US
*[[University of British Columbia]] (UBC), 1968 to 1998, Canada
*NUMAC ([[University of Newcastle upon Tyne]], [[University of Durham]], and [[Northumbria University|Newcastle Polytechnic]]),<ref name=NUMAC>[https://www.dur.ac.uk/cis/news/archive/issues/january2005/complete/ "How computers have changed since 1968"], ''ITS News'', Computing and Information Services, Durham University, 29 January 2005. Northumbrian Universities Multiple Access Computer (N.U.M.A.C.), a collaboration between of the universities of [[University of Durham|Durham]] (DUR), [[University of Newcastle upon Tyne|Newcastle upon Tyne]] (UNE) and [[Northumbria University|Newcastle Polytechnic]] that shared a S/360-67 at Newcastle starting in 1969</ref> 1969 to 1992, United Kingdom
*[[University of Alberta]] (UQV), 1971 to 1994,<ref name=UQVTimeline/> Canada
*[[Wayne State University]] (WSU), 1971 to 1998, US
*[[Rensselaer Polytechnic Institute]] (RPI), 1976 to 1999, US
*[[Simon Fraser University]] (SFU), 1977 to 1992,<ref>{{cite journal |citeseerx= 10.1.1.56.2631 |title= Dropping the Mainframe Without Crushing the Users: Mainframe to Distributed UNIX in Nine Months |first1= Peter |last1= Van Epp |first2= Bill |last2= Baines |location= Simon Fraser University |publisher=LISA VI Conference (Long Beach, California) |date=October 19–23, 1992}}</ref> Canada
*[[University of Durham]] (NUMAC),<ref name=NUMAC/> 1982 to 1992,<ref>In 1982 [https://www.dur.ac.uk/cis/news/archive/issues/january2005/complete/ "How computers have changed since 1968"], ''ITS News'', Computing and Information Services, Durham University, 29 January 2005. NUMAC installed a separate machine running MTS at the University of Durham, prior to that both DUR and UNE shared a single MTS system running at the University of Newcastle upon Tyne.</ref> United Kingdom

Several sites ran more than one MTS system: NUMAC ran two (first at Newcastle and later at Durham), Michigan ran three in the mid-1980s (UM for Maize, UB for Blue, and HG at Human Genetics), UBC ran three or four at different times (MTS-G, MTS-L, MTS-A, and MTS-I for general, library, administration, and instruction).

Each of the MTS sites made contributions to the development of MTS, sometimes by taking the lead in the design and implementation of a new feature and at other times by refining, enhancing, and critiquing work done elsewhere. Many MTS components are the work of multiple people at multiple sites.<ref>It is difficult to properly give credit for all the work that was done, however, to avoid giving too little credit and at the risk of not giving proper credit to everyone that made contributions, an attempt is made to note the sites where a major feature or enhancement was initially developed</ref>

In the early days collaboration between the MTS sites was accomplished through a combination of face-to-face site visits, phone calls, the exchange of documents and magnetic tapes by [[snail mail]], and informal get-togethers at [[SHARE (computing)|SHARE]] or other meetings. Later, e-mail, computer conferencing using [[CONFER (software)|CONFER]] and *Forum, network file transfer, and e-mail attachments supplemented and eventually largely replaced the earlier methods.

The members of the MTS Consortium produced a series of 82 ''MTS Newsletters'' between 1971 and 1982 to help coordinate MTS development.<ref name=MTSSubSeriesBentley>[https://quod.lib.umich.edu/cgi/f/findaid/findaid-idx?c=bhlead;idno=umich-bhl-0351;view=reslist;didno=umich-bhl-0351;subview=standard;focusrgn=C02;cc=bhlead;byte=24474999 Michigan Terminal System (MTS) subseries], Computing Center publications, 1965-1999, Bentley Historical Library, University of Michigan</ref>

[[File:MTSWorkshipVIIIMugs-1972.jpg|thumb|right|Mugs from MTS Workshop VIII, Ann Arbor, July 1982]]

Starting at UBC in 1974<ref>[https://babel.hathitrust.org/cgi/pt?id=mdp.39015006055027;view=1up;seq=5 ''Proceedings - MTS Systems Workshop''], 1974, University of British Columbia, Canada</ref> the MTS Consortium held annual ''MTS Workshops'' at one of the member sites. The workshops were informal, but included papers submitted in advance and ''Proceedings'' published after-the-fact that included session summaries.<ref name=MTSSubSeries2Bentley>[https://quod.lib.umich.edu/cgi/f/findaid/findaid-idx?c=bhlead;idno=umich-bhl-9551;view=reslist;didno=umich-bhl-9551;subview=standard;focusrgn=C01;cc=bhlead;byte=24586272 MTS (Michigan Terminal System) 1970-1986 series], Computing Center (University of Michigan) records, 1952-1996 and 1959-1987, Bentley Historical Library, University of Michigan</ref> In the mid-1980s several ''Western Workshops'' were held with participation by a subset of the MTS sites (UBC, SFU, UQV, UM, and possibly RPI).

The annual workshops continued even after MTS development work began to taper off. Called simply the "community workshop", they continued until the mid-1990s to share expertise and common experiences in providing computing services, even though MTS was no longer the primary source for computing on their campuses and some had stopped running MTS entirely.

===MTS sites===
In addition to the eight MTS Consortium sites that were involved in its development, MTS was run at a number of other sites, including:<ref name=WhyMTSSites/>

*[[Centro Brasileiro de Pesquisas Fisicas]] (CBPF)<ref>CBPF is the [http://portal.cbpf.br/index.php?page=home&lang=en Brazilian Center for Physics Research] {{webarchive |url=https://web.archive.org/web/20120410205344/http://portal.cbpf.br/index.php?page=home&lang=en |date=April 10, 2012}}</ref> within the [[Conselho Nacional de Desenvolvimento Científico e Tecnológico]] (CNPq),<ref>CNPq is the [http://memoria.cnpq.br/english/cnpq/index.htm National Council of Scientific and Technological Development] {{webarchive|url=https://web.archive.org/web/20130716063256/http://memoria.cnpq.br/english/cnpq/index.htm |date=2013-07-16}}</ref> Brazil
*[[Empresa Brasileira de Pesquisa Agropecuária]] (EMBRAPA),<ref>EMBRAPA is the [https://www.embrapa.br/en/home Brazilian Enterprise for Agricultural Research]</ref> Brazil
*[[Hewlett-Packard]] (HP), US
*[[Michigan State University]] (MSU), US
*[[Goddard Space Flight Center]], [[National Aeronautics and Space Administration]] (NASA), US

A copy of MTS was also sent to the [[University of Sarajevo]], Yugoslavia, though whether or not it was ever installed is not known.

[[INRIA]], the French national institute for research in computer science and control in Grenoble, France ran MTS on a trial basis, as did the [[University of Waterloo]] in Ontario, Canada, [[Southern Illinois University]], the [[Naval Postgraduate School]], [[Amdahl Corporation]], ST Systems for [[McGill University]] Hospitals, [[Stanford University]], and [[University of Illinois]] in the United States, and a few other sites.

==Hardware==
[[File:IBM360-67AtUmichWithMikeAlexander.jpg|thumb|right|Computing Center staff member Mike Alexander sitting at the console of the IBM System 360 Model 67 Duplex at the University of Michigan, 1969]]
[[File:Amdahl 470V-6 computer at U of M.jpg|thumb|right|Amdahl 470V/6 P2 at the University of Michigan, 1975]]

In theory MTS will run on the IBM S/360-67, any of the IBM S/370 series which include virtual memory, and their successors. MTS has been run
on the following computers in production, benchmarking, or trial configurations:<ref name=MTSVol1/>
*IBM: [[IBM System/360 Model 67|S/360-67]], [[IBM System/370#Series and models|S/370-148, S/370-168, 3033U, 4341, 4361, 4381, 3081D, 3081GX, 3083B, 3090–200, 3090–400, 3090–600, and ES/9000-720]]
*Amdahl: [[Amdahl Corporation|470V/6, 470V/7, 470V/8, 5860, 5870, 5990]]
*Hitachi: [[Hitachi|NAS 9060]]
*Various S/370 emulators

The University of Michigan installed and ran MTS on the first IBM S/360-67 outside of IBM (serial number 2) in 1967, the second Amdahl 470V/6 (serial number 2) in 1975,<ref>{{cite book|url=http://www.computerhistory.org/collections/accession/X436.84A|title=Amdahl 470/V6 mainframe computer - X436.84A - Computer History Museum|work=computerhistory.org|year=1975 }}</ref><ref>[https://docs.google.com/file/d/0B4t_NX-QeWDYaVpEZzNVTDRRdUdFaUJ5UjV5Q0xJQQ/edit "A performance Comparison of the Amdahl 470V/6 and the IBM 370/168"], Allan R. Emery and M. T. Alexander, a paper read at the meeting of the Computer Measurement Group, October 1975, San Francisco</ref> the first Amdahl 5860 (serial number 1) in 1982, and the first factory shipped IBM 3090–400 in 1986.<ref>Earlier 3090-400s were upgraded in the field from 3090-200s, [https://babel.hathitrust.org/cgi/pt?id=mdp.39015015410973;seq=203 "Installing the 3090"], ''UM Computing News'', vol 1, no. 8, 10 November 1986, p. 5</ref> NUMAC ran MTS on the first S/360-67 in the UK and very likely the first in Europe.<ref>[http://archive.michigan-terminal-system.org/discussions/how-did-sites-learn-about-and-make-the-decision-to-use-mts/3numac "E-mail from Ewan Page, First Director at NUMAC, to Denis Russell], 19 April 2011</ref> The University of British Columbia (UBC) took the lead in converting MTS to run on the [[IBM System/370|IBM S/370 series]] (an IBM S/370-168) in 1974. The University of Alberta installed the first Amdahl 470V/6 in Canada (serial number P5) in 1975.<ref name=UQVTimeline>{{cite web|url=https://www.ualberta.ca/~vbowler/HyperDispatch19/timeline.html|title=Timeline: Computing Services at the University of Alberta|work=ualberta.ca}}</ref> By 1978 NUMAC (at University of Newcastle upon Tyne and University of Durham) had moved main MTS activity on to its [[IBM System/370|IBM S/370 series]] (an IBM S/370-168).

MTS was designed to support up to four processors on the [[IBM System/360 Model 67|IBM S/360-67]], although IBM only produced one (simplex and half-duplex) and two (duplex) processor configurations of the Model 67. In 1984 RPI updated MTS to support up to 32 processors in the [[IBM System/370#Series and models|IBM S/370-XA]] (Extended Addressing) hardware series, although 6 processors is likely the largest configuration actually used.<ref>[http://archive.michigan-terminal-system.org/documentation/documents/MTSHistoryAtRPI-1989.pdf?attredirects=0 MTS History at RPI], 1989, 5p.</ref> MTS supports the IBM [[vector processor|Vector Facility]],<ref>[http://domino.research.ibm.com/tchjr/journalindex.nsf/600cc5649e2871db852568150060213c/c8f541b78dae5a6485256bfa00685bb2!OpenDocument "The IBM System/370 vector architecture"], W. Buchholz, ''IBM Systems Journal'', Volume 25, No. 1 (1986), pp. 51-62</ref> available as an option on the [[IBM System/370|IBM 3090]] and [[IBM ES/9000 family|ES/9000]] systems.

In early 1967 running on the single processor IBM S/360-67 at UM without [[virtual memory]] support, MTS was typically supporting 5 simultaneous terminal sessions and one batch job.<ref name=MTSVol1/> In November 1967 after virtual memory support was added, MTS running on the same IBM S/360-67 was simultaneously supporting 50 terminal sessions and up to 5 batch jobs.<ref name=MTSVol1/> In August 1968 a dual processor IBM S/360-67 replaced the single processor system, supporting roughly 70 terminal and up to 8 batch jobs.<ref name=Alexander1972>[https://drive.google.com/file/d/0B4t_NX-QeWDYTHFxRmI0a3dYNkU/view "Organization and features of the Michigan Terminal System"], M. T. Alexander, p. 586, ''Proceedings of the May 1972 AFIPS Spring Joint Computer Conference''</ref> By late 1991 MTS at UM was running on an IBM ES/9000-720 supporting over 600 simultaneous terminal sessions and from 3 to 8 batch jobs.<ref name=MTSVol1/>

MTS can be [[Booting#IBM System/360 and successors|IPL]]-ed under [[VM/370]], and some MTS sites did so, but most ran MTS on native hardware without using a [[virtual machine]].

==Features==
Some of the notable features of MTS include:<ref>[http://www.clock.org/~jss/work/mts/30years.html ''MTS Innovations in A History of MTS: 30 Years of Computing Service''], ''Information Technology Digest'', Volume 5, No. 5 (May 13, 1966), University of Michigan</ref>

{{Col-begin}}
{{Col-2}}
*The use of [[MTS system architecture#Virtual memory and paging|Virtual memory and Dynamic Address Translation (DAT)]] on the IBM S/360-67 in 1967.<ref name=MillsMTS>{{cite web|url=https://www.eecis.udel.edu/~mills/gallery/gallery8.html|title=Michigan Terminal System|work=udel.edu}}</ref>
*The use of multiprocessing on an IBM S/360-67 with two CPUs in 1968.
*Programs with access to (for the time) very large virtual address spaces.
*A straightforward [[MTS system architecture#Command language|command language]] that is the same for both terminal and batch jobs.
*A strong [[MTS system architecture#Device independent input/output|device independent input/output model]] that allows the same commands and programs to access terminals, disk files, printers, magnetic and paper tapes, card readers and punches, floppy disks, network hosts, and an audio response unit (ARU).
*A [[file system]] with support for "[[MTS system architecture#Line files|line files]]" where the line numbers and length of individual lines are stored as [[metadata]] separate from the data contents of the line, and the ability to read, insert, replace, and delete individual lines anywhere in the file without the need to read or write the entire file.<ref name=FileSystem1975>[https://ieeexplore.ieee.org/document/1451786?arnumber=1451786 "A file system for a general-purpose time-sharing environment"], G. C. Pirkola, ''Proceedings of the IEEE'', June 1975, volume 63 no. 6, pp.&nbsp;918–924, {{ISSN|0018-9219}}</ref>
*A file editor ($EDIT) with both command line and "visual" interfaces and pattern matching based on SNOBOL4 patterns.<ref name=MTSVol18>[https://deepblue.lib.umich.edu/handle/2027.42/79613 MTS Volume 18: ''MTS File Editor''], University of Michigan Computing Center, Ann Arbor, Michigan, 210 pp.</ref>
*The ability to share files in controlled ways (read, write-change, write-expand, destroy, permit).<ref name=Protection1977>[http://archive.michigan-terminal-system.org/documentation/documents/protection-1977.pdf?attredirects=0 "The Protection of Information in a General Purpose Time-Sharing Environment"], Gary C. Pirkola and John Sanguinetti, ''Proceedings of the IEEE Symposium on Trends and Applications 1977: Computer Security and Integrity'', vol. 10 no. 4, pp. 106-114</ref>
*The ability to permit files, not just to other user IDs and projects (aka groups), but to specific commands or programs and combinations of user IDs, projects, commands and programs.<ref name=Protection1977/>
*The ability for multiple users to manage simultaneous access to files with the ability to implicitly and explicitly lock and unlock files and to detect deadlocks.<ref name=FileSystem1975/>
{{Col-2}}
*Network host to host access from commands and programs as well as access to or from remote network printers, card readers and punches.<ref>{{cite web |url=http://www.merit.edu/about/history/article.php |title=A Chronicle of Merit's Early History |publisher=Merit Network |year=2008 |access-date=2008-09-15 |archive-url=https://web.archive.org/web/20090207130720/http://merit.edu/about/history/article.php |archive-date=2009-02-07 |url-status=dead }}—A university press release called a demonstration of the network (with a connection between UM and Wayne State University) on December 14, 1971, as "a milestone in higher education" and an "historic event."</ref>
*An e-mail system ([[MTS system architecture#Electronic mail|$MESSAGESYSTEM]]) that supports local and network mail with the ability to send to groups, to recall messages that haven't already been read, to add recipients to messages after they have been sent, and to display a history of messages in an e-mail chain without the need to include the text from older messages in each new message.<ref name=MTSVol23>[https://deepblue.lib.umich.edu/handle/2027.42/79615 MTS Volume 23: ''Messaging and Conferencing in MTS''], University of Michigan Computing Center, Ann Arbor, Michigan</ref>
*The ability to access tapes remotely, and to handle data sets that extend across multiple tapes efficiently.<ref name=MTSVol19>[https://deepblue.lib.umich.edu/handle/2027.42/79582 MTS Volume 19: ''Magnetic Tapes'' (The description of floppy-disk support has been removed from this volume.)], University of Michigan Computing Center, Ann Arbor, Michigan</ref>
*The availability of a rich collection of well-documented subroutine libraries.<ref name=MTSSubSeriesBentley/><ref name=MTSVol3>[https://deepblue.lib.umich.edu/handle/2027.42/79575 MTS Volume 3: ''System Subroutine Descriptions''], University of Michigan Computing Center, Ann Arbor, Michigan</ref><ref>"The Internal Design of the
IG Routines, an Interactive Graphics System for a Large Timesharing Environment", James Blinn and Andrew Goodrich, ''SIGGRAPH Proceedings'', 1976, pp. 229-234</ref>
*The ability for multiple users to quickly load and use a collection of common reentrant subroutines, which are available in shared virtual memory.
*The availability of compilers, assemblers, and a Symbolic Debugging System (SDS) that allow users to debug programs written in high-level languages such as FORTRAN, Pascal, PL/I, ... as well as in assembly language.
*A strong protection model that uses the virtual memory hardware and the S/360 and S/370 hardware's supervisor and problem states and via software divides problem state execution into system (privileged or unprotected) and user (protected or unprivileged) modes. Relatively little code runs in supervisor state. For example, Device Support Routines (DSRs, aka device drivers) are not part of the supervisor and run in system mode in problem state rather than in supervisor state.<ref name=Sanguinetti1981>[https://dl.acm.org/citation.cfm?doid=850716.850719 "The use of the monitor call instruction to implement domain switching in the IBM 370 architecture"], John Sanguinetti, University of Michigan Computing Center, ''ACM SIGOPS Operating Systems Review'', Volume 15, Issue 4 (October 1981), pp.55-61</ref><ref>[https://dl.acm.org/citation.cfm?doid=850693.850694 "A penetration analysis of the Michigan Terminal System"], B. Hebbard, P. Grosso, et al., ''ACM SIGOPS Operating Systems Review'', Volume 14, Issue 1 (January 1980), pp.7-20</ref>
*A simulated [[MTS system architecture#Branch on Program Interrupt (BPI)|Branch on Program Interrupt]] (BPI) instruction.<ref name=MTSVol4>[https://deepblue.lib.umich.edu/handle/2027.42/79622 MTS Volume 14: ''360/370 Assemblers in MTS''], University of Michigan Computing Center, Ann Arbor, Michigan</ref>
{{Col-end}}

===Programs developed for MTS===
The following are some of the notable programs developed for MTS:<ref name=MTSVol2>[https://deepblue.lib.umich.edu/handle/2027.42/79612 MTS Volume 2: ''Public File Descriptions''], University of Michigan Computing Center, Ann Arbor, Michigan</ref>

{{Col-begin}}
{{Col-2}}
*Awit, a computer chess program written in Algol W by Tony Marsland.<ref>{{cite web|url=https://chessprogramming.wikispaces.com/Awit|title=chessprogramming - Awit|work=Archived from wikispaces.com|archive-url=https://web.archive.org/web/20131206072704/https://chessprogramming.wikispaces.com/Awit|archive-date=2013-12-06}}</ref>
*Chaos, one of the leading computer chess programs from 1973 through 1985. Written in FORTRAN Chaos started at RCA Systems Programming division in Cinnaminson, NJ with Fred Swartz and Victor Berman as first authors, Mike Alexander and others joined the team later and moved development to MTS at the UM Computing Center.<ref>{{cite web|url=http://chessprogramming.wikispaces.com/Chaos|title=chessprogramming - Chaos|work=archived from wikispaces.com|archive-url=https://web.archive.org/web/20131205052308/http://chessprogramming.wikispaces.com/Chaos|archive-date=2013-12-05}}</ref>
*[[CONFER (software)|CONFER II]], one of the first computer conferencing systems. CONFER was developed by Robert Parnes starting in 1975 while he was a graduate student and with support from the [[University of Michigan]]'s [http://www.crlt.umich.edu/ Center for Research on Learning and Teaching (CRLT)] and School of Education.<ref>[https://dl.acm.org/citation.cfm?id=800191.805559 "Computer-based educational communications at the University of Michigan"], Karl L. Zinn, Robert Parnes, and Helen Hench, [http://www.crlt.umich.edu/ Center for Research on Learning and Teaching (CRLT)], [[University of Michigan]], ''Proceedings of the ACM Annual Conference/Meeting'', 1976, pages 150-154</ref><ref>[http://www.umich.edu/~umscp/history.html The History of the Student Conferencing Project], University of Michigan, c. 1997</ref>
*FakeOS, a simulator that allows object modules containing OS/360 SVCs, control blocks, and references to OS/360 access methods to execute under MTS.
*Forum, a computer conferencing system developed by staff of the Computing Centre at the [[University of British Columbia]] (UBC).
*[[MAD programming language|GOM]] (Good Old Mad), a compiler for the 7090 [[MAD programming language|MAD language]] converted to run under MTS by Don Boettner of the UM's Computing Center.<ref name=GOM>[http://archive.michigan-terminal-system.org/documentation/documents/GOMManual-June1989.pdf ''GOM: Good Old Mad''], Donald Boettner, June 1989, University of Michigan Computing Center, 110p.</ref>
*IF (Interactive Fortran), developed by the [[University of British Columbia]] Computing Centre.<ref name=UBCIF-1973>[https://8d4ec138056a43619549adaab53ffb70b717bf4c.googledrive.com/host/0B4t_NX-QeWDYZi1rdUtBMVRUUEd2RWM3dFd0dHhMdw/IF-Interactive-Fortran-Compiler-SHARE%2041-13to17August1973-MiamiBeachFlorida.pdf "IF: An Interactive FORTRAN compiler"] {{webarchive|url=https://web.archive.org/web/20141216013824/https://8d4ec138056a43619549adaab53ffb70b717bf4c.googledrive.com/host/0B4t_NX-QeWDYZi1rdUtBMVRUUEd2RWM3dFd0dHhMdw/IF-Interactive-Fortran-Compiler-SHARE%2041-13to17August1973-MiamiBeachFlorida.pdf |date=2014-12-16}}, Ron Hall, ''SHARE 41 Proceedings'', 15 August 1973, Miami Beach, Florida, 8 pages.</ref>
{{Col-2}}
*[[MICRO Relational Database Management System|MICRO Information Management System]], one of the earliest relational database management systems implemented in 1970 by the Institute for Labor and Industrial Relations (ILIR) at the University of Michigan.<ref name=MICROManual1977>[https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B4t_NX-QeWDYZGMwOTRmOTItZTg2Zi00YmJkLTg4MTktN2E4MWU0YmZlMjE3 ''MICRO Information Management System (Version 5.0) Reference Manual''], M.A. Kahn, D.L. Rumelhart, and B.L. Bronson, October 1977, Institute of Labor and Industrial Relations (ILIR), University of Michigan and Wayne State University</ref><ref>[https://docs.google.com/open?id=0B4t_NX-QeWDYZGJqRVBaSEdMVnc ''MICRO: A Relational Database Management System''], Harry F. Clark, David E. Hetrick, Robert C. Bressan, July 1992, Institute of Labor and Industrial Relations (ILIR), University of Michigan, 451 pages, {{ISBN|9780877363507}}</ref>
*MIDAS (Michigan Interactive Data Analysis System), an interactive statistical analysis package developed by Dan Fox and others at UM's Statistical Research Laboratory.<ref>[https://babel.hathitrust.org/cgi/pt?id=mdp.39015000966526 ''Documentation for MIDAS: Michigan Interactive Data Analysis System''], by Daniel J. Fox and Kenneth E. Guire, 1974, Statistical Research Laboratory University of Michigan, Ann Arbor</ref>
*[[UBC PLUS|Plus]], a programming language developed by Alan Ballard and Paul Whaley of the Computing Centre at the University of British Columbia (UBC).<ref name=UBCPlus-1984>[https://docs.google.com/file/d/0B4t_NX-QeWDYYlYydkNuQjFTU3k0dHg5VUpWQXJOdw/edit "The Plus Systems Programming Language"], Alan Ballard and Paul Whaley, in ''Proceedings of Canadian Information Processing Society (CIPS) Congress 84'', June 1984.</ref><ref name=UBCPlus>[http://archive.michigan-terminal-system.org/documentation/documents/Plus-1987.pdf ''UBC PLUS: The Plus Programming Language''], Allan Ballard and Paul Whaley, October 1987, University of British Columbia Computing Centre, 198pp.</ref>
*TAXIR, an information storage and retrieval system designed for taxonomic data at the University of Colorado by David Rogers, Henry Fleming, Robert Brill, and George Estabrook and ported to MTS and enhanced by Brill at the University of Michigan.<ref>[https://eric.ed.gov/?id=ED064063 ''The Taxir Primer''], R. C. Brill, 1971, Colorado Univ., Boulder. Inst. of Arctic and Alpine Research</ref>
*Textform, a text-processing program developed at the University of Alberta's Computing Centre to support device independent output to a wide range of devices from line printers, to the Xerox 9700 page printers, to advanced phototypesetting equipment using fixed width and proportional fonts.<ref>[https://docs.google.com/file/d/0B4t_NX-QeWDYQUJaejBXYV9RcUdkUDJCYWNrVmVRZw/edit "A New Tool for Publishing Printed Material"], TEXTFORM Group, University of Alberta, ''Share 48 Proceedings'', Vol II, pp. 1042-1056, 1977.</ref><ref>[https://docs.google.com/file/d/0B4t_NX-QeWDYZ3ZlVllLVGdRV0s1NHo4cE5XOFRodw/edit "Publishing, Word Processing and TEXTFORM"], Grant Crawford, University of Alberta, in Canadian Information Processing Society (CIPS) Session '78 Proceedings, pp. 88-92, 1978.</ref><ref>[https://www.worldcat.org/oclc/020087914 ''Textform''], Computing Services, University of Alberta, 1984, 216 p.</ref><ref>[http://www.bitsavers.org/pdf/univOfMichigan/mts/memos/r1028-TEXTFORMReferenceManual-Jan1986.pdf ''Textform Reference Manual''], Computing Center, University of Michigan, January 1986.</ref>
*VSS, a simulator developed at the [[University of British Columbia]]'s Computing Centre that makes it possible to run OS/MFT, OS/MVT, VS1, and MVS application programs under MTS.
{{Col-end}}

===Programs that run under MTS===
The following are some of the notable programs ported to MTS from other systems:<ref name=MTSVol2/>

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{{Col-2}}
*APL VS, IBM's APL VS compiler program product.
*ASMH, a version of IBM's 370 assembler with enhancements from SLAC and MTS.
*COBOL VS, IBM's COBOL VS compiler program product.
*CSMP, IBM's Continuous System Modeling Program.<ref>{{cite journal | url=https://www.sciencedirect.com/science/article/abs/pii/S0378475474800030 | doi=10.1016/S0378-4754(74)80003-0 | title=Continuous-system simulation languages: A state-of-the-art survey | date=1974 | last1=Nilsen | first1=Ragnar N. | last2=Karplus | first2=Walter J. | journal=Mathematics and Computers in Simulation | volume=16 | pages=17–25 | url-access=subscription }}</ref>
*Fortran, the G, H, and VS compilers from IBM.
*GASP, a FORTRAN based discrete simulation package.<ref>''Simulation with GASP II'', A. A. B. Pritzker and Philip J. Kiviat, Prentice-Hall, 1969</ref>
*[[Kermit (protocol)|Kermit]], [[Columbia University]]'s communications software and protocol<ref name="dacruz19840106">{{cite mailing list |url=http://kermit.columbia.edu/kermit/e/mail.84a |title=Announcing KERMIT for MTS |publisher=Kermit Project, Columbia University |mailing-list=Info-Kermit Digest |date=1984-01-06 |access-date=23 February 2016 |author=da Cruz, Frank }}</ref>
*MPS, IBM's Mathematical Programming System/360.<ref name="Version 2 1971">''MPS/360 Version 2, Linear and Separable Programming User's Manual'' (GH20-0476), 1971, IBM Corporation</ref>
*[[Nastran|NASTRAN]], finite element analysis program originally developed by and for [[NASA]].<ref>[http://www.mscsoftware.com/support/library/conf/wuc82/p00282.pdf ''MSC/NASTRAN at the University of Michigan''], William J. Anderson and Robert E. Sandstorm, 1982, University of Michigan College of Engineering</ref>
*OSIRIS (Organized Set of Integrated Routines for Investigations with Statistics), a collection of statistical analysis programs developed at the [https://isr.umich.edu/ University of Michigan's Institute for Social Research] (ISR).<ref>{{Cite journal |last=Van Eck |first=Neal A. |date=1980 |title=Statistical Analysis and Data Management Highlights of OSIRIS IV |url=https://www.jstor.org/stable/2684124 |journal=The American Statistician |volume=34 |issue=2 |pages=119–121 |doi=10.2307/2684124 |jstor=2684124 |issn=0003-1305|url-access=subscription }}</ref>
*PascalSB, the Stony Brook Pascal compiler.
*Pascal/SLAC, the Pascal compiler from the Stanford Linear Accelerator Center.
{{Col-2}}
*Pascal VS, IBM's Pascal VS compiler program product.
*PL/I Optimizing Compiler from IBM.
*REDUCE2, an algebraic language implemented in [[LISP]].<ref>[https://dl.acm.org/citation.cfm?doid=800204.806277 "REDUCE 2: A system and language for algebraic manipulation"], ''Proceedings of the Second ACM Symposium on Symbolic and Algebraic Manipulation'', 1971, pages 128-133</ref>
*[[SAS (software)|SAS]] (Statistical Analysis System).
*[[SHAZAM (software)|SHAZAM]], a package for estimating, testing, simulating and forecasting econometrics and statistical models
*[[SIMSCRIPT II.5]], a free-form, English-like, general-purpose discrete event simulation language.<ref>[http://www.caciasl.com/cust_center/ss3docs/zbuildin.pdf ''Building Simulation models with SIMSCRIPT II.5''], Edward C. Russell, 1999, CACI, Los Angeles, CA</ref>
*[[SPIRES]] (Stanford Public Information Retrieval System), a database management system.
*[[SPSS]] (Statistical Package for the Social Sciences)
*[[Tellagraf|TELL-A-GRAPH]], a proprietary conversational graphics program from [https://www.bloomberg.com/research/stocks/private/snapshot.asp?privcapId=30311 ISSCO] of San Diego, CA.<ref>[http://hdl.handle.net/2027/mdp.39015026567563?urlappend=%3Bseq=801 ''TELL-A-GRAF in MTS''], Dave Whipple, Computing Center Memo 450, University of Michigan, March 1983.</ref>
*TEX, [[Donald Knuth|Don Knuth]]'s [[TeX]] text-processing program.<ref>[http://web.mit.edu/jgross/www/LaTeX/texbook.pdf ''The Texbook''] by [[Don Knuth]], 1984, Addison-Wesley Publishing Company, 496 pages, {{ISBN|0201134489}}.</ref>
*TROLL, econometric modeling and statistical analysis<ref>[https://www.intex.com/troll/history.html History of TROLL], Portable TROLL Online Help, Intex Solutions, Inc. (Boston), 1996. Retrieved June 19, 2014.</ref>
{{Col-end}}

===Programming languages available under MTS===
MTS supports a rich set of programming languages, some developed for MTS and others ported from other systems:<ref name=MTSVol2/>

{{Col-begin}}
{{Col-2}}
*[[ALGOL W]]<ref>[https://deepblue.lib.umich.edu/handle/2027.42/79617 MTS Volume 16: ''ALGOL W in MTS''], University of Michigan Computing Center, Ann Arbor, Michigan</ref>
*[[ALGOL 68]]<ref>[http://www.diegolucenapumar.com/sda3/home/Algol/Algol%2068/Algol68-RevisedReport.pdf ''Revised Report on the Algorithmic Language ALGOL 68 (PDF)''] {{webarchive|url=https://web.archive.org/web/20140410224348/http://www.diegolucenapumar.com/sda3/home/Algol/Algol%2068/Algol68-RevisedReport.pdf |date=2014-04-10}}, A. van Wijngaarden, et al.</ref>
*[[APL (programming language)|APL]] (IBM's VS APL)<ref>[https://babel.hathitrust.org/cgi/pt?id=mdp.39015026567563;view=1up;seq=213 Computing Center CCMemo 435: ''MTS VS APL User's Guide''], Edward J. Fronczak, Computing Center, University of Michigan, August 1982.</ref><ref>[https://dl.acm.org/citation.cfm?id=1098666 ''A Programming Language''], K. E. Iverson, 1962, John Wiley &amp; Sons, 315 pages, {{ISBN|0-471430-14-5}}.</ref><ref>[http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/apl/GC26-3847-2_APL_Language_Jun76.pdf ''APL Language''], IBM publication GC26-3874.</ref><ref>[http://bitsavers.informatik.uni-stuttgart.de/pdf/ibm/apl/GH20-0689-2_APL_360_Primer_Aug71.pdf ''APL\360 Primer''], IBM publication GH20-0689.</ref>
*[[Assembly language|Assembler]] (360/370: G, H, Assist; DEC PDP-11)
*[[BASIC]] (BASICUM),<ref>[https://deepblue.lib.umich.edu/handle/2027.42/79608 MTS Volume 10: ''Basic in MTS''], University of Michigan Computing Center, Ann Arbor, Michigan</ref> WBASIC<ref name=MTSVol2/><ref>[https://catalog.hathitrust.org/Record/000769505 ''Waterloo BASIC - A Structured Programming Approach, Primer and Reference Manual''], J. W. Grahm, et al., 1980, WATFAC Publications Ltd., Waterloo, Ontario, Canada</ref>
*[[BCPL]]<ref>[http://www.fh-jena.de/~kleine/history/languages/Richards-BCPL-ReferenceManual.pdf ''The BCPL Reference Manual''] {{Webarchive|url=https://web.archive.org/web/20141021222418/http://www.fh-jena.de/~kleine/history/languages/Richards-BCPL-ReferenceManual.pdf |date=2014-10-21 }}, Memorandum M-352, Project MAC, Cambridge, July, 1967</ref> (Basic Combined Programming Language)
*[[C (programming language)|C]]
*[[COBOL]] (ANSI,<ref>[http://bitsavers.trailing-edge.com/pdf/ibm/360/os/cobol/GC28-6396-5_IBM_OS_Full_American_National_Standard_COBOL_Jun75.pdf ''IBM OS Full American National Standard COBOL System Library Manual''], IBM publication GC28-6396.</ref> VS,<ref>[https://babel.hathitrust.org/cgi/pt?id=mdp.39015026567563;view=1up;seq=563 CCMemo 439: ''IBM VS COBOL under MTS''], Howard Young, Computing Center, University of Michigan, June 1982.</ref> [[Watcom|WATBOL]])
*EXPL<ref>[https://babel.hathitrust.org/cgi/pt?id=mdp.39015026567571;view=1up;seq=379 CCMemo 416: ''EXPL - Extended XPL''], Pat Sherry, Computing Center, University of Michigan, May 1980.</ref> (Extended [[XPL]])
*[[FORTRAN]]<ref name=MTSVol6>[https://deepblue.lib.umich.edu/handle/2027.42/79601 MTS Volume 6: ''FORTRAN in MTS''], University of Michigan Computing Center, Ann Arbor, Michigan</ref> (G, H, VS, [[WATFIV (programming language)|WATFOR, WATFIV]])
*GASP (A FORTRAN-based discrete simulation language)
*[[MAD (programming language)|GOM]] ('''G'''ood '''O'''ld '''M'''ad, the [[IBM 7090|7090]] [[Michigan Algorithm Decoder]] ported to the S/370 architecture)<ref name=GOM/>
*[[GPSS|GPSS/H]]<ref>[https://catalog.hathitrust.org/Record/002952023 ''GPSS/H Reference Manual''], James O. Henriksen and Robert C. Crain, Wolverine Software Corp., 1989.</ref> (General Purpose Simulation System V)<ref>''IBM General Purpose Simulation System V User's Manual'', IBM publication SH20-0851</ref><ref>[http://www.computinghistory.org.uk/det/3088/Simulation-Using-GPSS/ ''Simulation Using GPSS''], [[Thomas J. Schriber]], 1974, John Wiley &amp; Sons, 533 pages, {{ISBN|0471763101}}.</ref>
*[[Icon (programming language)|ICON]]<ref>[https://dl.acm.org/citation.cfm?id=577914 ''The ICON Programming Language''], Ralph E. Griswold and Madge T. Griswold, 1983, Prentice-Hall, N.Y., 336 pages, {{ISBN|0134497775}}.</ref>
*IF (Interactive FORTRAN, an incremental compiler and environment for executing and debugging [[FORTRAN]] programs, developed at the [[University of British Columbia]])<ref name=UBCIF-1973/>
*[[MAD (programming language)|MAD/I]] (an expanded version of the [[Michigan Algorithm Decoder]] for the IBM S/360 architecture that is not compatible with the original [[IBM 7090|7090]] version of MAD, see also GOM above)
{{Col-2}}
*MPS, IBM's Mathematical Programming System/360<ref name="Version 2 1971"/>
*[[LISP|MTS LISP]] 1.5<ref>[https://deepblue.lib.umich.edu/handle/2027.42/79591 MTS Volume 8: ''LISP and SLIP in MTS''], University of Michigan Computing Center, Ann Arbor, Michigan</ref> (a new implementation of LISP 1.5<ref>[http://www.softwarepreservation.org/projects/LISP/book/LISP%201.5%20Programmers%20Manual.pdf/view ''LISP 1.5 Programmer's Manual''], J. McCarthy, et al., 1962, MIT Press, Cambridge, MA</ref> developed at the UM's [[Mental Health Research Institute (Michigan)|Mental Health Research Institute]], MHRI)
*[[Pascal (programming language)|Pascal]]<ref>[https://deepblue.lib.umich.edu/handle/2027.42/79595 MTS Volume 20: ''PASCAL in MTS''], University of Michigan Computing Center, Ann Arbor, Michigan</ref> (VS,<ref>[https://babel.hathitrust.org/cgi/pt?id=mdp.39015026567563;view=1up;seq=311 CCMemo 436: ''Pascal VS in MTS''], Douglas Orr, Computing Center, University of Michigan, August 1982.</ref><ref>[http://bitsavers.trailing-edge.com/pdf/ibm/370/pascal/SH20-6168-1_VS_PASCAL_Dec81.pdf ''Pascal/VS Language Reference Manual''] {{Webarchive|url=https://web.archive.org/web/20141211030518/http://bitsavers.trailing-edge.com/pdf/ibm/370/pascal/SH20-6168-1_VS_PASCAL_Dec81.pdf |date=2014-12-11 }}, IBM publication SH20-6168.</ref> JB)
*PIL, PIL/2 (Pitt Interpretive Language)<ref>[https://deepblue.lib.umich.edu/handle/2027.42/79630 MTS Volume 12: ''PIL/2 in MTS''], University of Michigan Computing Center, Ann Arbor, Michigan</ref>
*[[PL/I]]<ref>[https://deepblue.lib.umich.edu/handle/2027.42/79580 MTS Volume 7: ''PL/I in MTS''], University of Michigan Computing Center, Ann Arbor, Michigan</ref> (F and OPT from IBM, PL/C from [[Cornell University]])
*[[PL/M]]
*[[PL360]]<ref>{{cite journal |doi= 10.1145/321439.321442 |volume=15 |title=PL360, a Programming Language for the 360 Computers |year=1968 |journal=Journal of the ACM |pages=37–74 |last1= Wirth |first1= Niklaus|s2cid=7376057 |doi-access=free }}</ref>
*[[Plus (programming language)|Plus]]<ref name=UBCPlus-1984/><ref name=UBCPlus/> (A "Pascal-like" system implementation language from the [[University of British Columbia]] (UBC) based on the SUE<ref name=SueManual>[https://dl.acm.org/citation.cfm?doid=800234.807062 "The System Language for Project SUE"], B. L. Clark and J. J. Horning of the Computer Systems Research Group and Department of Computer Science, University of Toronto, ''Proceedings of the SIGPLAN symposium on Languages for system implementation'', 1971, pp.79-88</ref> system language developed at the University of Toronto, c. 1971)
*[[Prolog]]
*[[Simula]]<ref>[http://www.idi.ntnu.no/grupper/su/publ/simula/holmevik-simula-ieeeannals94.pdf "Compiling Simula: A historical study of technological genesis"] {{Webarchive|url=https://web.archive.org/web/20170830065454/http://www.idi.ntnu.no/grupper/su/publ/simula/holmevik-simula-ieeeannals94.pdf |date=2017-08-30 }}, Jan Rune Holmevik, ''IEEE Annals in the History of Computing'', Volume 16 No. 4, 1994, pp.25-37</ref>
*SUE<ref name=SueManual/>
*[[SNOBOL4]]<ref name=MTSVol9>[https://deepblue.lib.umich.edu/handle/2027.42/79574 MTS Volume 9: ''SNOBOL4 in MTS''], University of Michigan Computing Center, Ann Arbor, Michigan</ref> (String Oriented Symbolic Language)<ref>[https://www.worldcat.org/oclc/299498419 ''The SNOBOL4 Programming Language''], Griswold, Ralph E., J. F. Poage, and I. P. Polonsky, Englewood Cliffs, NJ, 1968, Prentice Hall</ref>
*[[SPITBOL]]<ref name=MTSVol9/> (Speedy Implementation of [[SNOBOL]])
*UMIST<ref name=MTSVolII-1967>[http://www.bitsavers.org/pdf/univOfMichigan/mts/Michigan_Terminal_System_Second_Edition_Vol2_Dec67.pdf MTS Volume II], second edition, December 1, 1967, University of Michigan Computing Center, Ann Arbor, Michigan, 415 p.</ref> (University of Michigan Interpretive String Translator, based on [[TRAC (programming language)|TRAC]])<ref>[https://dl.acm.org/citation.cfm?doid=365230.365270 "TRAC, A Procedure-Describing Language for the Reactive Typewriter"], Calvin N. Mooers, ''Communications of the ACM'', Vol.9 No.3 (March 1966), pp.215-219, {{ISSN|0001-0782}}</ref>
{{Col-end}}

==System architecture==
{{main|MTS system architecture}}

{| class="wikitable" style="text-align: center;"
|+ MTS Architecture<ref>[http://hdl.handle.net/2027.42/79606 MTS Lecture 1], a transcription of the first in a series of lectures on the internals of the Michigan Terminal System given by Mike Alexander, Don Boettner, Jim Hamilton, and Doug Smith, c. 1972</ref> 
!  
!State
!Mode<ref name=Protection1977/>
!VM
!Interrupts
|-
|align="center" |User programs
|align="center" rowspan=3|problem
|align="center" |user
|align="center" rowspan=2 {{yes|on}}
|align="center" rowspan=3 {{yes|on}}
|-
|align="center" |Command Language Subsystems (CLSs),<BR>Device Support Routines (DSRs),<BR>System Subroutines
|align="center" rowspan=2|system
|-
|align="center" |Job programs (MTS, PDP, DMGR, RM or HASP, ...)
|align="center" {{yes-no|on or off}}
|-
|align="center" |Supervisor (UMMPS)
|align="center" |supervisor
|align="center" {{n/a|n/a}}
|align="center" {{no|off}}
|align="center" {{no|off}}
|-
|align="center" |S/360-67 or S/370 hardware
|align="center" colspan="4"|  
|}

UMMPS, the supervisor, has complete control of the hardware and manages a collection of job programs.<ref name=Alexander1972/> One of the job programs is MTS, the job program with which most users interact.<ref name=MTSVol1/> MTS operates as a collection of command language subsystems (CLSs). One of the CLSs allows for the execution of user programs. MTS provides a collection of system subroutines that are available to CLSs, user programs, and MTS itself.<ref name=MTSVol3/> Among other things these system subroutines provide standard access to Device Support Routines (DSRs), the components that perform device dependent input/output.

==Manuals and documentation==
The lists that follow are quite University of Michigan centric. Most other MTS sites used some of this material, but they also produced their own manuals, memos, reports, and newsletters tailored to the needs of their site.

===End-user documentation===
The manual series ''MTS: The Michigan Terminal System'', was published from 1967 through 1991, in volumes 1 through 23, which were updated and reissued irregularly.<ref name=MTSSubSeriesBentley/> Initial releases of the volumes did not always occur in numeric order and volumes occasionally changed names when they were updated or republished. In general, the higher the number, the more specialized the volume.

The earliest versions of ''MTS Volume I and II'' had a different organization and content from the MTS volumes that followed and included some internal as well as end user documentation. The second edition from December 1967 covered:
*''MTS Volume I'': Introduction; Concepts and facilities; Calling conventions; Batch, Terminal, Tape, and Data Concentrator user's guides; Description of UMMPS and MTS; Files and devices; Command language; User Programs; Subroutine and macro library descriptions; Public or library file descriptions; and Internal specifications: Dynamic loader (UMLOAD), File and Device Management (DSRI prefix and postfix), Device Support Routines (DSRs), and File routines<ref name=MTSVolI-1967>[http://www.bitsavers.org/pdf/univOfMichigan/mts/Michigan_Terminal_System_Second_Edition_Vol1_Dec67.pdf MTS Volume I], second edition, December 1, 1967, University of Michigan Computing Center, Ann Arbor, Michigan, 415 p.</ref>
*''MTS Volume II'': Language processor descriptions: F-level assembler; FORTRAN G; IOH/360; PIL; SNOBOL4; UMIST; WATFOR; and 8ASS (PDP-8 assembler)<ref name=MTSVolII-1967/>

The following ''MTS Volumes'' were published by the University of Michigan Computing Center<ref name=MTSVol1/> and are available as PDFs:<ref name=MTSAtDeepBlue>[https://deepblue.lib.umich.edu/handle/2027.42/79570 "Computing Center" collection] within "Archival Collections -- Bentley Library" of the University of Michigan's Deep Blue digital archive</ref><ref name=MTSAtHathiTrust>[https://babel.hathitrust.org/cgi/mb?a=listis;c=1889583521 UM Computing Center Public Category] in the Hathi Trust Digital Library</ref><ref name=MTSAtBitSavers>[http://www.bitsavers.org/pdf/univOfMichigan/mts/ MTS PDF Document Archive] at BitSavers.org</ref><ref>[http://archive.michigan-terminal-system.org/documentation#TOC-MTS-Volumes Manuals and Documentation section] of the MTS Archive Web site ([http://archive.michigan-terminal-system.org archive-Michigan-Terminal-System.org] {{Webarchive|url=https://web.archive.org/web/20110111201148/http://archive.michigan-terminal-system.org/ |date=2011-01-11 }})</ref>

{{Col-begin}}
{{Col-3}}
*MTS Volume 1: ''The Michigan Terminal System'', 1991
*MTS Volume 2: ''Public File Descriptions'', 1990
*MTS Volume 3: ''Subroutine and Macro Descriptions'', 1989
*MTS Volume 4: ''Terminals and Networks in MTS'', 1988 (earlier ''Terminals and Tapes'')
*MTS Volume 5: ''System Services'', 1985
*MTS Volume 6: ''FORTRAN in MTS'', 1988
*MTS Volume 7: ''PL/I in MTS'', 1985
*MTS Volume 8: ''LISP and SLIP in MTS'', 1983
*MTS Volume 9: ''SNOBOL4 in MTS'', 1983
*MTS Volume 10: ''BASIC in MTS'', 1980
*MTS Volume 11: ''Plot Description System'', 1985
*MTS Volume 12: ''PIL/2 in MTS'', 1974
{{Col-3}}
*MTS Volume 13: ''The Symbolic Debugging System'', 1985 (earlier ''Data Concentrator User's Guide'')
*MTS Volume 14: ''360/370 Assemblers in MTS'', 1986
*MTS Volume 15: ''FORMAT and TEXT360'', 1988
*MTS Volume 16: ''ALGOL W in MTS'', 1980
*MTS Volume 17: ''Integrated Graphics System'', 1984
*MTS Volume 18: ''MTS File Editor'', 1988
*MTS Volume 19: ''Tapes and Floppy Disks'', 1993
*MTS Volume 20: ''PASCAL in MTS'', 1989
*MTS Volume 21: ''MTS Command Extensions and Macros'', 1991
*MTS Volume 22: ''Utilisp in MTS'', 1988
*MTS Volume 23: ''Messaging and Conferencing in MTS'', 1991
{{Col-3}}
[[File:MTSVol1Cover.png|thumb|MTS Volume 1 cover]]
{{Col-end}}

*''MTS Reference Summary'', a ~60 page, 3" x 7.5", pocket guide to MTS, Computing Center, University of Michigan
*''The Taxir primer: MTS version'', Brill, Robert C., Computing Center, University of Michigan
*''Fundamental Use of the Michigan Terminal System'', Thomas J. Schriber, 5th Edition (revised), Ulrich's Books, Inc., Ann Arbor, MI, 1983, 376 pp.
*''Digital computing, FORTRAN IV, WATFIV, and MTS (with *FTN and *WATFIV)'', Brice Carnahan and James O Wilkes, University of Michigan, Ann Arbor, MI, 1968–1979, 1976 538 p.
*''Documentation for MIDAS, Michigan Interactive Data Analysis System'', Statistical Research Laboratory, University of Michigan<ref>[https://babel.hathitrust.org/cgi/mb?a=listis;c=498865425 MIDAS public category] at the Hathi Trust Digital Library</ref>
*''OSIRIS III MTS Supplement'', Center for Political Studies, University of Michigan<ref>[https://babel.hathitrust.org/cgi/mb?a=listis;c=2013821674 OSIRIS public category] at the Hathi Trust Digital Library</ref>

Various aspects of MTS at the University of Michigan were documented in a series of ''Computing Center Memos'' (CCMemos)<ref name=MTSAtHathiTrust/><ref name=CCPubsSubSeriesBentley>[https://quod.lib.umich.edu/cgi/f/findaid/findaid-idx?c=bhlead;idno=umich-bhl-0351;view=reslist;didno=umich-bhl-0351;subview=standard;focusrgn=C01;cc=bhlead;byte=24453394 Unit Publications series], Computing Center publications, 1965-1999, Bentley Historical Library, University of Michigan</ref> which were published irregularly from 1967 through 1987, numbered 2 through 924, though not necessarily in chronological order. Numbers 2 through 599 are general memos about various software and hardware; the 600 series are the Consultant's Notes series—short memos for beginning to intermediate users; the 800 series covers issues relating to the Xerox 9700 printer, text processing, and typesetting; and the 900 series covers microcomputers. There was no 700 series. In 1989 this series continued as ''Reference Memos'' with less of a focus on MTS.<ref>[https://quod.lib.umich.edu/cgi/f/findaid/findaid-idx?c=bhlead;idno=umich-bhl-9551;view=reslist;didno=umich-bhl-9551;subview=standard;focusrgn=C01;cc=bhlead;byte=24586272 Unit Publications series], Information Technology Division (University of Michigan) publications, 1971-1999, Bentley Historical Library, University of Michigan</ref><ref>[http://hdl.handle.net/2027.42/79611 ITD Publications], University of Michigan, Ann Arbor, November 1995, 24 pages</ref>

[[File:ITDDigestCover.jpg|thumb|Cover page of the May 1996 issue of University of Michigan IT Digest, May 1996]]
A long run of newsletters targeted to end-users at the University of Michigan with the titles ''Computing Center News'', ''Computing Center Newsletter'', ''U-M Computing News'', and the ''Information Technology Digest'' were published starting in 1971.<ref name=MTSAtHathiTrust/><ref name=CCPubsSubSeriesBentley/>

There was also introductory material presented in the ''User Guide'', ''MTS User Guide'', and ''Tutorial'' series, including:<ref name=MTSAtHathiTrust/>

*''Getting connected—Introduction to Terminals and Microcomputers''
*''Introduction to the Computing Center''
*''Introduction to Computing Center services''
*''Introduction to Database Management Systems on MTS''
*''Introduction to FORMAT''
*''Introduction to Magnetic Tapes''
*''Introduction to MTS''
*''Introduction to the MTS File Editor''
*''Introduction to Programming and Debugging in MTS''
*''Introduction to Terminals''
*''Introduction to Terminals and Microcomputers''

===Internals documentation===
The following materials were not widely distributed, but were included in MTS Distributions:<ref name=MTSSubSeriesBentley/><ref name=MTSAtDeepBlue/><ref name=MTSAtBitSavers/>

*MTS Operators Manual<ref>[http://hdl.handle.net/2027.42/79628 MTS Operators Manual], February 1995, University of Michigan, 574p.</ref>
*MTS Message Manual
*MTS Volume ''n'': Systems Edition<ref>[http://hdl.handle.net/2027.42/79585 MTS Volume 1: Systems Edition, Obsolete and Internal MTS Commands], November 1991, University of Michigan, 60pp.</ref><ref>[http://hdl.handle.net/2027.42/79583 MTS Volume 3: Systems Edition, Subroutine Description], April 1981, University of Michigan, 50pp.</ref>
*MTS Volume 99: Internals Documentation<ref>[http://hdl.handle.net/2027.42/79596 MTS Volume 99: Internal Documentation], 1972-1978, University of Michigan, 167pp.</ref>
*Supervisor Call Descriptions<ref>[http://hdl.handle.net/2027.42/79584 UMMPS D6.0 Supervisor Call Descriptions], November 1987, University of Michigan, 156p.</ref>
*Disk Disaster Recovery Procedures<ref>[http://hdl.handle.net/2027.42/79618 MTS Disk Disaster Recovery], April 1987, 14pp.</ref>
*A series of lectures describing the architecture and internal organization of the Michigan Terminal System given by Mike Alexander, Don Boettner, Jim Hamilton, and Doug Smith (4 audio tapes, lecture notes, and transcriptions)

==Distribution==
The University of Michigan released MTS on magnetic tape on an irregular basis.<ref name=MTSSubSeriesBentley/> There were full and partial distributions, where ''full distributions'' (D1.0, D2.0, ...) included all of the MTS components and ''partial distributions'' (D1.1, D1.2, D2.1, D2.2, ...) included just the components that had changed since the last full or partial distribution. Distributions 1.0 through 3.1 supported the IBM S/360 Model 67, distribution 3.2 supported both the IBM S/360-67 and the IBM S/370 architecture, and distributions D4.0 through D6.0 supported just the IBM S/370 architecture and its extensions.

MTS distributions included the updates needed to run licensed program products and other proprietary software under MTS, but not the base proprietary software itself, which had to be obtained separately from the owners. Except for IBM's Assembler H, none of the licensed programs were required to run MTS.

The last MTS distribution was D6.0 released in April 1988. It consisted of 10,003 files on six 6250&nbsp;bpi magnetic tapes. After 1988, distribution of MTS components was done in an ad hoc fashion using network file transfer.

To allow new sites to get started from scratch, two additional magnetic tapes were made available, an [[Initial Program Load#IBM System/360 and successors|IPLable]] ''boot tape'' that contained a minimalist version of MTS plus the [[Direct Access Storage Device|DASDI]] and DISKCOPY utilities that could be used to initialize and restore a ''one disk pack starter version'' of MTS from the second magnetic tape. In the earliest days of MTS, the standalone [[TSS/360|TSS]] DASDI and DUMP/RESTORE utilities rather than MTS itself were used to create the one-disk starter system.

There were also less formal ''redistributions'' where individual sites would send magnetic tapes containing new or updated work to a coordinating site. That site would copy the material to a common magnetic tape (RD1, RD2, ...), and send copies of the tape out to all of the sites. The contents of most of the redistribution tapes seem to have been lost.

Today, complete materials from the six full and the ten partial MTS distributions as well as from two redistributions created between 1968 and 1988 are available from the Bitsavers Software archive<ref name=MTSOnBitsavers>[http://bitsavers.org/bits/univOfMichigan/mts/ MTS Distributions] on Bitsavers.org</ref><ref name=BitsaversOverview>[http://archive.michigan-terminal-system.org/documentation/mts-distributions Overview of MTS Distribution materials] available at Bitsavers.org, accessed 21 January 2012</ref> and from the University of Michigan's Deep Blue digital archive.<ref>[http://deepblue.lib.umich.edu/handle/2027.42/89588 Michigan Terminal System (MTS) Distribution Files], Deep Blue digital archive, University of Michigan, accessed 21 January 2012</ref><ref>[http://archive.michigan-terminal-system.org/documentation/mts-distributions-at-u-m-s-deep-blue-digital-archive?pli=1 Overview of MTS Distribution Materials] available from the University of Michigan's Deep Blue digital archive, accessed 21 January 2012</ref>

Working with the D6.0 distribution materials, it is possible to create an [[booting#IBM System/360 and successors|IPLable]] version of MTS. A new D6.0A distribution of MTS makes this easier.<ref>[http://archive.michigan-terminal-system.org/mts-d60A "MTS D6.0A - A pre-built MTS system for use with the Hercules S/370 emulator"], MTS Archive, accessed 21 January 2012</ref> D6.0A is based on the D6.0 version of MTS from 1988 with various fixes and updates to make operation under Hercules in 2012 smoother. In the future, an IPLable version of MTS will be made available based upon the version of MTS that was in use at the University of Michigan in 1996 shortly before MTS was shut down.<ref name=BitsaversOverview/>

==Licensing==
As of December 22, 2011, the MTS Distribution materials are freely available under the terms of the [[Creative Commons]] Attribution 3.0 Unported License (CC BY 3.0).<ref>[http://bitsavers.org/bits/univOfMichigan/mts/_COPYRIGHT.txt MTS Copyright, Warranty, and Limitation of Liability statement], Bitsavers.org, accessed 22 December 2011</ref>

In its earliest days MTS was made available for free without the need for a license to sites that were interested in running MTS and which seemed to have the knowledgeable staff required to support it.

In the mid-1980s licensing arrangements were formalized with the University of Michigan acting as agent for and granting licenses on behalf of the MTS Consortium.<ref>[http://bitsavers.informatik.uni-stuttgart.de/bits/univOfMichigan/mts/mtsDistDoc/d6.0/D6.0-MTS-DOC.txt "MTS Licensing Statement"], November 1986, Leonard J. Harding, [https://quod.lib.umich.edu/b/bhlead/umich-bhl-9551?byte=145563004;focusrgn=C01;subview=standard;view=reslist MTS (Michigan Terminal System), 1968-1996], Box 22, Computing Center records 1952-1996, Bentley Historical Library, University of Michigan</ref> MTS licenses were available to academic organizations for an annual fee of $5,000, to other non-profit organizations for $10,000, and to commercial organizations for $25,000. The license restricted MTS from being used to provide commercial computing services. The licensees received a copy of the full set of MTS distribution tapes, any incremental distributions prepared during the year, written installation instructions, two copies of the current user documentation, and a very limited amount of assistance.

Only a few organizations licensed MTS. Several licensed MTS in order to run a single program such as CONFER. The fees collected were used to offset some of the common expenses of the MTS Consortium.

==See also==
*[[Merit Network]]
*[[Time-sharing system evolution]]

==References==
{{Reflist |colwidth=30em}}

==External links==
{{Wikisource|The Paging Game}}

===Archives===
*[http://archive.michigan-terminal-system.org MTS Archive] {{Webarchive|url=https://web.archive.org/web/20110111201148/http://archive.michigan-terminal-system.org/ |date=2011-01-11 }}, a collection of documents, photographs, movies, and other materials related to MTS and the organizations and people that developed and used it
*[http://bitsavers.org/bits/univOfMichigan/mts/ MTS distribution archive] at Bitsavers'
*[https://deepblue.lib.umich.edu/handle/2027.42/89588 MTS distribution archive] at the University of Michigan's Deep Blue digital archive
*[http://archive.michigan-terminal-system.org/mts-d60A MTS D6.0A] - A pre-built version of MTS for use with the Hercules S/370 emulator, available from the MTS Archive
*[http://www.bitsavers.org/pdf/univOfMichigan/mts/ MTS PDF Document Archive] at Bitsavers'
*The [https://babel.hathitrust.org/cgi/mb?a=listis;c=1889583521 UM Computing Center Public Collection] at the [http://www.hathitrust.org/ Hathi Trust Digital Library] contains full text versions of over 250 documents related to MTS that are available for online viewing.
*The [http://deepblue.lib.umich.edu/handle/2027.42/79570 Computing Center collection] in the University of Michigan's Deep Blue digital archive contains over 50 items, mostly PDFs, but also a few videos, related to MTS and the U-M Computing Center.

===Papers===
*[https://sites.google.com/site/michiganterminalsystem/documentation/documents/Hinson1971.pdf?attredirects=0 ''A Comparative Study of the Michigan Terminal System (MTS) with Other Time Sharing Systems for the IBM 360/67 Computer''], Elvert F. Hinson, Master's thesis, Naval Postgraduate School, Monterey, CA., December 1971
*[https://dl.acm.org/citation.cfm?doid=961053.961101 "Measurement and Performance of a Multiprogramming System"], B. Arden and D. Boettner, ''Proceedings of the 2nd ACM Symposium on Operating Systems Principles'', pp.&nbsp;130–46, October 1969
*[https://www.merit.edu/about/history/ Merit Network History]
*[http://archive.michigan-terminal-system.org/bibliography MTS Bibliography], a list of published literature about MTS
*[https://dl.acm.org/citation.cfm?doid=1232909.1232910 "MTS - Michigan Terminal System"], Donald W. Boettner and Michael T. Alexander, ''ACM SIGOPS Operating Systems Review'', Volume 4, Issue 4 (December 1970)
*[https://dx.doi.org/10.1109/PROC.1975.9855 "The Michigan Terminal System"], Donald W. Boettner and Michael T. Alexander, ''Proceedings of the IEEE'', Volume 63, Issue 6 (June 1975), pp.&nbsp;912–918
*[https://docs.google.com/viewer?a=v&pid=explorer&chrome=true&srcid=0B4t_NX-QeWDYNzQ0MGQ4OGItYzlhZi00MjQzLWJmNDctNDU3ZWY4MTBhNzUz&hl=en_US "A Faster Cratchit - The History of Computing at Michigan"], Vol. XXVII, No. 1 (January 1976), ''U-M Research News'', 24 pages

===Web sites===
*[http://mtswiki.westwood-tech.com/ MTS History], collected by former [[University of Michigan]] Computing Center staff member Tom Valerio
*[https://www.everything2.com/title/Michigan+Terminal+System Personal perspective on MTS] by Dan Boulet a student and later Computing Services staff member at the [[University of Alberta]]
*[https://web.archive.org/web/20110607132852/https://www.msu.edu/~mrr/mycomp/mts/mtsframe.htm Personal reflections on MTS] by Mark Riordan of [[Michigan State University]]'s Computer Laboratory
*[http://www.clock.org/~jss/work/mts/ Several articles] from the May 13, 1996 issue of the University of Michigan Information Technology Digest, Volume 5, No. 5, giving the history of and reminiscences about MTS, Merit, and UMnet on the eve of MTS's retirement at the University of Michigan, preserved on Web pages created by Josh Simon
*[https://try-mts.com/why-try-mts/ Try-MTS.com], a web site showing how to run MTS under the Hercules emulator, tutorials on using the system and on several of the programming languages available on MTS
*[https://www.vintagebigblue.org/MTSr6.0A/MTS3270/mts3270.php Public MTS Terminal], logon and look around like a student would in the 90's

{{Time-sharing operating systems}}

[[Category:Time-sharing operating systems]]
[[Category:IBM mainframe operating systems]]
[[Category:Discontinued operating systems]]
[[Category:Formerly proprietary software]]
[[Category:History of software]]
[[Category:University of Michigan]]
[[Category:1967 software]]