Editing Time-sharing (section)

===Time-sharing business===
'''Genesis'''

In the 1960s, several companies started providing time-sharing services as [[service bureau]]s. Early systems used [[Teletype Model 33]] KSR or ASR or Teletype Model 35 KSR or ASR machines in [[ASCII]] environments, and [[IBM Selectric typewriter]]-based terminals (especially the [[IBM 2741]]) with two different seven-bit codes.<ref>{{cite book
 |title=IBM 2741 Communication Terminal
 |publisher=IBM
 |page=12
 |url=http://www.textfiles.com/bitsavers/pdf/ibm/27xx/GA24-3415-3_2741_Data_Terminal_Aug72.pdf
 |access-date=2015-10-06
 |archive-date=2017-03-16
 |archive-url=https://web.archive.org/web/20170316041750/http://www.textfiles.com/bitsavers/pdf/ibm/27xx/GA24-3415-3_2741_Data_Terminal_Aug72.pdf
 |url-status=dead
 }}</ref> They would connect to the [[Centralized computing|central computer]] by [[dial-up]] Bell 103A modem or [[acoustic coupler|acoustically coupled]] [[modem]]s operating at 10&ndash;15 characters per second. Later terminals and modems supported 30&ndash;120 characters per second. The time-sharing system would provide a complete operating environment, including a variety of programming language processors, various software packages, file storage, bulk printing, and off-line storage. Users were charged rent for the terminal, a charge for hours of connect time, a charge for seconds of CPU time, and a charge for kilobyte-months of disk storage.

Common systems used for time-sharing included the [[SDS 940]], the [[PDP-10]], the [[IBM 360]], and the [[GE-600 series]]. Companies providing this service included [[GE]]'s [[GXS Inc.|GEISCO]], the [[IBM]] subsidiary The [[Service Bureau Corporation]], [[Tymnet|Tymshare]] (founded in 1966), [[National CSS]] (founded in 1967 and bought by Dun & Bradstreet in 1979), Dial Data (bought by Tymshare in 1968), [[Applied Logic Corporation|AL/COM]], [[Bolt, Beranek, and Newman]] (BBN) and [[Time Sharing Limited | Time Sharing Ltd.]] in the [[United Kingdom|UK]].<ref>Jeffrey R. Yost, ''Making IT Work: A History of the Computer Services Industry'', 2017, ISBN 0262342197 p. 158</ref> By 1968, there were 32 such service bureaus serving the US [[National Institutes of Health]] (NIH) alone.<ref>"Information Technology Corporate Histories Collection". Computer History Museum. Retrieved on 2013-11-29 from http://www.computerhistory.org/corphist/view.php?s=stories&id=136.</ref> The ''Auerbach Guide to Timesharing'' (1973) lists 125 different timesharing services using equipment from [[Burroughs Corporation|Burroughs]], [[Control Data Corporation|CDC]], [[Digital Equipment Corporation|DEC]], [[Hewlett-Packard|HP]], [[Honeywell]], [[IBM]], [[RCA]], [[Univac]], and [[Scientific Data Systems|XDS]].<ref name=Auerbach>{{cite book|title=Auerbach Guide to Time Sharing|year=1973|publisher=Auerbach Publishers, Inc.|url=http://bitsavers.trailing-edge.com/pdf/auerbach/GuideToTimesharing_Jan73.pdf|access-date=2013-11-29}}</ref><ref name="DECpro1">DEC Timesharing (1965), by Peter Clark, The DEC Professional, Volume 1, Number 1</ref>

====Rise and fall====
In 1975, acting president of [[Prime Computer]] Ben F. Robelen told stockholders that "The biggest end-user market currently is time-sharing".<ref name="upton19750611">{{Cite magazine |last=Upton |first=Molly |date=1975-06-11 |title=Prime President Predicts '75 Orders On Target, Despite Recent Slowdown |url=https://books.google.com/books?id=79Vx176yQBEC&pg=PA35 |access-date=2024-10-23 |magazine=Computerworld |page=35}}</ref> For DEC, for a while the second largest computer company (after IBM), this was also true: Their [[PDP-10]] and IBM's [[IBM System/360 Model 67|360/67]]<ref>One Two-page IBM print ad was headlined "100 or more people can use IBM's new time-sharing computer at the same time." Originals were/are? on eBay</ref> were widely used<ref>p.1425, Encyclopedia of Computer Science, Litton Educational Publishing, Inc.</ref> by commercial timesharing services such as CompuServe, [[Embarq#History|On-Line Systems, Inc.]] (OLS), Rapidata and [[TELCOMP|Time Sharing Ltd.]]

The advent of the [[personal computer]] marked the beginning of the decline of time-sharing.{{Citation needed|date=November 2022|reason=There may other reasons.}} The economics were such that computer time went from being an expensive resource that had to be shared to being so cheap that computers could be left to sit idle for long periods in order to be available as needed.{{Citation needed|date=November 2022|reason=Some computers are still expensive resources.}}

=====Rapidata as an example=====
Although many time-sharing services simply closed, Rapidata<ref>https://groups.google.com/forum/#!topic/alt.folklore.computers/aE4TwORruB8 - "I worked for RapiData Timesharing for about a year circa 1969..."</ref><ref>someone else: "I worked there for almost 2 years 1977 to 1979." alt.folklore.computers/aE4TwORruB8/EdpKfFAlBncJ</ref> held on, and became part of [[McKesson Corporation|National Data Corporation]].<ref>{{Cite web |date=2023-05-26 |title=Stocks |url=https://www.bloomberg.com/markets/stocks |access-date=2023-05-26 |website=Bloomberg.com |language=en}}</ref> It was still of sufficient interest in 1982 to be the focus of "A User's Guide to Statistics Programs: The Rapidata Timesharing System".<ref>Bruce Bosworth, {{ISBN|978-089529-1-677}}</ref> Even as revenue fell by 66%<ref>''[[Computerworld]]'', Oct. 6, 1986, p.179, "Rapidata revenue was $11 million ... in 1986, down from ... ($31 million in 1982)."</ref> and National Data subsequently developed its own problems, attempts were made to keep this timesharing business going.<ref>Computerworld, Aug.25,1986, p.5,
"National Data Corp. said it is close to reaching an agreement with a buyer of its Rapidata timesharing division. In May, National Data said it would close down ..."</ref><ref>National Data Corp became NDC-Health Corp in 2001 (bizjournals.com/atlanta/stories/2001/10/29/daily25.html)</ref><ref>As for a place in history, Rapidata is listed in 'The AUERBACH Guide to Time Sharing (1973)' http://bitsavers.informatik.uni-stuttgart.de/pdf/auerbach/GuideToTimesharing_Jan73.pdf</ref>

=====UK=====
* [[Time Sharing Limited]] (TSL, 1969–1974) - launched using DEC systems. [[PERT]] was one of its popular offerings. TSL was acquired by [[Automatic Data Processing|ADP]] in 1974.
* OLS Computer Services (UK) Limited (1975–1980) - using HP & DEC systems.