Editing Time-sharing (section)

===Time-sharing===
[[File:Unix Timesharing UW-Madison 1978.jpeg|thumb|[[Unix]] time-sharing at the [[University of Wisconsin]], 1978]]

The concept is claimed to have been first described by Robert Dodds in a letter he wrote in 1949 although he did not use the term ''time-sharing''.<ref name="Lee1992">{{cite journal |last1=Lee |first1=J.A.N. |title=Claims to the term 'time-sharing' |journal=IEEE Annals of the History of Computing |date=1992 |volume=14 |issue=1 |pages=16–54 |doi=10.1109/85.145316 |s2cid=30976386 }}</ref> Later [[John Backus]] also described the concept, but did not use the term, in the 1954 summer session at [[Massachusetts Institute of Technology|MIT]].<ref name="jbackus">Backus, John, ''[http://bitsavers.org/pdf/mit/whirlwind/summer_session_1954/Digital_Computers_Advanced_Coding_Techniques_Summer_1954.pdf Digital Computers: Advanced Coding Techniques] {{Webarchive|url=https://web.archive.org/web/20220806082146/http://bitsavers.org/pdf/mit/whirlwind/summer_session_1954/Digital_Computers_Advanced_Coding_Techniques_Summer_1954.pdf |date=2022-08-06 }}'', MIT 1954, page 16-2. The first known description of computer time-sharing.</ref> [[Bob Bemer]] used the term ''time-sharing'' in his 1957 article "How to consider a computer" in ''Automatic Control Magazine'' and it was reported the same year he used the term ''time-sharing'' in a presentation.<ref name="Lee1992"/><ref>{{cite web |last1=Bemer |first1=Bob
|title=Origins of Timesharing |url=http://www.bobbemer.com/TIMESHAR.HTM |website=bobbemer.com
|date=March 1957 |access-date=June 24, 2016 |url-status = dead
|archive-url = https://web.archive.org/web/20170702215126/http://www.bobbemer.com/TIMESHAR.HTM
|archive-date = 2017-07-02}}</ref><ref>{{cite arXiv |last1=Middleburg |first1=C.A.
|title=Searching Publications on Operating Systems |eprint=1003.5525 |class=cs.OS |year=2010}}</ref> In a paper published in December 1958, W. F. Bauer wrote that "The computers would handle a number of problems concurrently. Organizations would have input-output equipment installed on their own premises and would buy time on the computer much the same way that the average household buys power and water from utility companies."<ref name="wfbauer">{{cite conference |last1=Bauer |first1=W. F. |title=Computer design from the programmer's viewpoint] |url=https://www.computer.org/web/csdl/index/-/csdl/proceedings/afips/1958/5053/00/50530046.pdf |conference=[[Joint Computer Conference|Eastern Joint Computer Conference]] |archive-url=https://web.archive.org/web/20160723012920/https://www.computer.org/web/csdl/index/-/csdl/proceedings/afips/1958/5053/00/50530046.pdf |archive-date=2016-07-23 |date=December 1958 |quote=One of the first descriptions of computer time-sharing. |url-status=dead}}</ref>

[[Christopher Strachey]], who became [[University of Oxford|Oxford University's]] first professor of computation, filed a patent application in the United Kingdom for "time-sharing" in February 1959.<ref>{{Cite web|title=Computer Pioneers - Christopher Strachey|url=https://history.computer.org/pioneers/strachey.html|access-date=2020-01-23|website=history.computer.org|quote=What Strachey proposed in his concept of time-sharing was an arrangement that would preserve the direct contact between programmer and machine, while still achieving the economy of multiprogramming.}}</ref><ref>{{Cite web|title=Computer - Time-sharing and minicomputers|url=https://www.britannica.com/technology/computer/Time-sharing-and-minicomputers|access-date=2020-01-23|website=Encyclopedia Britannica|language=en|quote=In 1959 Christopher Strachey in the United Kingdom and John McCarthy in the United States independently described something they called time-sharing.}}</ref> He gave a paper "Time Sharing in Large Fast Computers"<ref>{{cite conference |conference=UNESCO Information Processing conference |last1=Strachey |first1=Christopher |author1-link=Christopher Strachey |title=Time sharing in large fast computers |url=https://archive.org/details/large-fast-computers/ |access-date=30 May 2023 |date=1959-06-15}}</ref> at the first [[International Federation for Information Processing#History|UNESCO Information Processing Conference]] in Paris in June that year, where he passed the concept on to [[J. C. R. Licklider]].<ref>{{Cite book|last1=Gillies|first1=James M.|url=https://archive.org/details/howwebwasbornsto00gill/page/12/mode/2up?q=strachey|title=How the Web was Born: The Story of the World Wide Web|last2=Gillies|first2=James|last3=Gillies|first3=James|last4=Cailliau|first4=Robert|date=2000|publisher=Oxford University Press|isbn=978-0-19-286207-5|pages=13|language=en|url-access=registration}}</ref> This paper was credited by the [[MIT Computation Center]] in 1963 as "the first paper on time-shared computers".<ref name="ctsspg">F. J. Corbató, et al., ''[http://www.bitsavers.org/pdf/mit/ctss/CTSS_ProgrammersGuide.pdf The Compatible Time-Sharing System A Programmer's Guide]'' (MIT Press, 1963) {{ISBN|978-0-262-03008-3}}. "To establish the context of the present work, it is informative to trace the development of time-sharing at MIT. Shortly after the first paper on time-shared computers by C. Strachey at the June 1959 UNESCO Information Processing conference, H.M. Teager and J. McCarthy delivered an unpublished paper "Time-Shared Program Testing" at the August 1959 ACM Meeting."</ref>

The meaning of the term ''time-sharing'' has shifted from its original usage. Up until 1960, time-sharing was used to refer to [[multiprogramming]] without multiple user sessions.<ref name="Lee1992"/> Later, it came to mean sharing a computer [[Interactive computing|interactively]] among multiple users. In 1984 Christopher Strachey wrote he considered the change in the meaning of the term ''time-sharing'' a source of confusion and not what he meant when he wrote his paper in 1959.<ref name="Lee1992"/>

There are also examples of systems which provide multiple user consoles but only for specific applications, they are not general-purpose systems. These include [[Semi-Automatic Ground Environment|SAGE]] (1958), [[Sabre (travel reservation system)|SABRE]] (1960)<ref name="Lee1992" /> and [[PLATO (computer system)|PLATO II]] (1961), created by [[Donald Bitzer]] at a public demonstration at [[Robert Allerton Park]] near the University of Illinois in early 1961. Bitzer has long said that the PLATO project would have gotten the patent on time-sharing if only the University of Illinois had not lost the patent for two years.<ref>Brian Dear, Chapter 4 -- The Diagram, [https://books.google.com/books?id=D5ZBDwAAQBAJ&pg=PA71 The Friendly Orange Glow], Pantheon Books, New York, 2017; pages 71-72 discuss the development of time-sharing and the University of Illinois loss of the patent.</ref>

The first [[Interactivity|interactive]], general-purpose time-sharing system usable for software development, [[Compatible Time-Sharing System]], was initiated by [[John McCarthy (computer scientist)|John McCarthy]] at MIT writing a memo in 1959.<ref>{{Cite web |title=Reminiscences on the Theory of Time-Sharing |url=http://jmc.stanford.edu/computing-science/timesharing.html |access-date=2020-01-23 |website=John McCarthy's Original Website |quote=in 1960 'time-sharing' as a phrase was much in the air. It was, however, generally used in my sense rather than in John McCarthy's sense of a CTSS-like object.}}</ref> [[Fernando J. Corbató]] led the development of the system, a prototype of which had been produced and tested by November 1961.<ref name="50th">{{cite web |url=https://multicians.org/thvv/compatible-time-sharing-system.pdf |title=Compatible Time-Sharing System (1961-1973): Fiftieth Anniversary Commemorative Overview |editor-last1=Walden |editor-first1=David |editor-last2=Van Vleck |editor-first2=Tom |editor2-link=Tom Van Vleck |date=2011 |publisher=IEEE Computer Society |access-date=February 20, 2022}}</ref> [[Philip M. Morse]] arranged for IBM to provide a series of their mainframe computers starting with the [[IBM 704]] and then the [[IBM 709]] product line [[IBM 7090]] and [[IBM 7094]].<ref name="50th" /> IBM loaned those mainframes at no cost to MIT along with the staff to operate them and also provided hardware modifications mostly in the form of [[Request price quotation|RPQ]]s as prior customers had already commissioned the modifications.<ref>{{cite book |last=Watson Jr. |first=Thomas J. |author-link=Thomas J. Watson Jr. |date=1990 |title=Father, Son, and Co.: My Life at IBM and Beyond |location=New York |publisher=Bantam Books |page=244-245 |isbn=9780553070118 |quote=When we started delivering our first commercial machines, our customers often found that the most difficult thing about having a computer was finding somebody who could run it. We couldn't produce all those technicians ourselves. Yet there was not a single university with a computer curriculum. So I went up to MIT in the mid-1950s and urged them to start training computer scientists. We made a gift of a large computer and the money to run it.}}</ref><ref name="50th" /> There were certain stipulations that governed MIT's use of the loaned IBM hardware. MIT could not charge for use of CTSS.<ref>{{cite journal |last1=Lee |first1=J.A.N. |last2=Rosin |first2=Robert F |date=1992 |title=Time-Sharing at MIT |url=https://archive.org/details/time-sharing-at-mit |journal=IEEE Annals of the History of Computing |volume=14 |issue=1 |pages=18 |doi=10.1109/85.145317 |s2cid=30631012 |access-date=October 3, 2022 | quote=Corbato: No, that was one of the interesting aspects. One of the terms of IBM's donation for the use of the equipment was that we were not to charge for it. It was free all right.}}</ref> MIT could only use the IBM computers for eight hours a day; another eight hours were available for other colleges and universities; IBM could use their computers for the remaining eight hours, although there were some exceptions. In 1963 a second deployment of CTSS was installed on an IBM 7094 that MIT has purchased using [[DARPA|ARPA]] money. This was used to support [[Multics]] development at [[Project MAC]].<ref name="50th" />

[[JOSS]] began time-sharing service in January 1964.<ref>{{cite book | chapter=JOSS: a designer's view of an experimental on-line computing system | author = J. C. Shaw | title=Proceeding AFIPS '64 (Fall, part I) Proceedings of the October 27-29, 1964, fall joint computer conference, part I | year=1964 | pages=455–464 | doi = 10.1145/1464052.1464093 | isbn = 9781450378895 | s2cid = 16483923 | chapter-url=http://dl.acm.org/citation.cfm?id=1464093}}</ref> [[Dartmouth Time-Sharing System]] (DTSS) began service in March 1964.<ref name="Rankin">{{Citation | last = Rankin| first = Joy Lisi | title = A People's History of Computing in the United States | place = Cambridge, Massachusetts | publisher = Harvard University Press | year = 2018| isbn = 9780674970977 }}</ref>