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In
computing Computing is any goal-oriented activity requiring, benefiting from, or creating computing machinery. It includes the study and experimentation of algorithmic processes, and development of both hardware and software. Computing has scientific, ...
, time-sharing is the sharing of a computing resource among many users at the same time by means of multiprogramming and multi-tasking.DEC Timesharing (1965), by Peter Clark, The DEC Professional, Volume 1, Number 1 Its emergence as the prominent model of computing in the 1970s represented a major technological shift in the history of computing. By allowing many users to interact concurrently with a single computer, time-sharing dramatically lowered the cost of providing computing capability, made it possible for individuals and organizations to use a computer without owning one, and promoted the interactive use of computers and the development of new interactive
application Application may refer to: Mathematics and computing * Application software, computer software designed to help the user to perform specific tasks ** Application layer, an abstraction layer that specifies protocols and interface methods used in a c ...
s.


History


Batch processing

The earliest computers were extremely expensive devices, and very slow in comparison to later models. Machines were typically dedicated to a particular set of tasks and operated by control panels, the operator manually entering small programs via switches in order to load and run a series of programs. These programs might take hours to run. As computers grew in speed, run times dropped, and soon the time taken to start up the next program became a concern. Newer
batch processing Computerized batch processing is a method of running software programs called jobs in batches automatically. While users are required to submit the jobs, no other interaction by the user is required to process the batch. Batches may automatically ...
software and methodologies, including batch operating systems such as
IBSYS IBSYS is the discontinued tape-based operating system that IBM supplied with its IBM 709, IBM 7090 and IBM 7094 computers. A similar operating system (but with several significant differences), also called IBSYS, was provided with IBM 7040 a ...
(1960), decreased these "dead periods" by queuing up programs ready to run. Comparatively inexpensive card punch or
paper tape Five- and eight-hole punched paper tape Paper tape reader on the Harwell computer with a small piece of five-hole tape connected in a circle – creating a physical program loop Punched tape or perforated paper tape is a form of data storage ...
writers were used by programmers to write their programs "offline". Programs were submitted to the operations team, which scheduled them to be run. Output (generally printed) was returned to the programmer. The complete process might take days, during which time the programmer might never see the computer. Stanford students made a short film humorously critiquing this situation. The alternative of allowing the user to operate the computer directly was generally far too expensive to consider. This was because users might have long periods of entering code while the computer remained idle. This situation limited interactive development to those organizations that could afford to waste computing cycles: large universities for the most part.


Time-sharing

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''. Later John Backus also described the concept, but did not use the term, in the 1954 summer session at MIT,Backus, John,
Digital Computers: Advanced Coding Techniques
'', MIT 1954, page 16-2. The first known description of computer time-sharing.
. 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. In a paper published in December 1958 by W. F. Bauer,Bauer, . .,
Computer design from the programmer's viewpoint
'' (Eastern Joint Computer Conference, December 1958) One of the first descriptions of computer time-sharing.
he 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." Christopher Strachey, who became Oxford University's first professor of computation, filed a patent application for "time-sharing" in February 1959. He gave a paper "Time Sharing in Large Fast Computers" at the first UNESCO Information Processing Conference in Paris in June that year, where he passed the concept on to
J. C. R. Licklider Joseph Carl Robnett Licklider (; March 11, 1915 – June 26, 1990), known simply as J. C. R. or "Lick", was an American psychologistMiller, G. A. (1991), "J. C. R. Licklider, psychologist", ''Journal of the Acoustical Society of Am ...
. This paper was credited by the MIT Computation Center in 1963 as "the first paper on time-shared computers".F. J. Corbató, et al.,
The Compatible Time-Sharing System A Programmer's Guide
' (MIT Press, 1963) . "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."
The meaning of the term ''time-sharing'' has shifted from its original usage. From 1949-1960, time-sharing was used to refer to multiprogramming without multiple-interactive user sessions. 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 1960. There are also examples of systems which provide multiple user consoles but only for specific applications, they are not general-purpose systems. These include SAGE (1958),
SABRE A sabre (French: �sabʁ or saber in American English) is a type of backsword with a curved blade associated with the light cavalry of the early modern and Napoleonic periods. Originally associated with Central European cavalry such as t ...
(1960) and
PLATO Plato ( ; grc-gre, Πλάτων ; 428/427 or 424/423 – 348/347 BC) was a Greek philosopher born in Athens during the Classical period in Ancient Greece. He founded the Platonist school of thought and the Academy, the first institution ...
II, created by
Donald Bitzer Donald L. Bitzer (born January 1, 1934) is an American electrical engineer and computer scientist. He was the co-inventor of the plasma display, is largely regarded as the "father of PLATO", and has made a career of improving classroom productivit ...
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. The first interactive, general-purpose time-sharing system usable for software development, Compatible Time-Sharing System, was initiated by John McCarthy at MIT writing a memo in 1959 and then Fernando J. Corbató spearheading the actual development of the system.
Philip M. Morse Philip McCord Morse (August 6, 19035 September 1985), was an American physicist, administrator and pioneer of operations research (OR) in World War II. He is considered to be the father of operations research in the U.S. Biography Morse graduat ...
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. 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 RPQs as prior customers had already commissioned the modifications. There were certain stipulations that governed MIT's use of the loaned IBM hardware. MIT could not charge for use of CTSS. 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 ARPA money. This was used to support
Multics Multics ("Multiplexed Information and Computing Service") is an influential early time-sharing operating system based on the concept of a single-level memory.Dennis M. Ritchie, "The Evolution of the Unix Time-sharing System", Communications of ...
development at Project MAC. JOSS began time-sharing service in January 1964. Dartmouth Time Sharing System began service in March 1964.


Development

Throughout the late 1960s and the 1970s, computer terminals were multiplexed onto large institutional
mainframe computer A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterprise ...
s ( centralized computing systems), which in many implementations sequentially polled the terminals to see whether any additional data was available or action was requested by the computer user. Later technology in interconnections were interrupt driven, and some of these used parallel data transfer technologies such as the IEEE 488 standard. Generally, computer terminals were utilized on college properties in much the same places as '' desktop computers'' or ''
personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or te ...
s'' are found today. In the earliest days of personal computers, many were in fact used as particularly smart terminals for time-sharing systems. The Dartmouth Time Sharing System's creators wrote in 1968 that "any response time which averages more than 10 seconds destroys the illusion of having one's own computer". Conversely, timesharing users thought that their terminal was the computer. With the rise of microcomputing in the early 1980s, time-sharing became less significant, because individual microprocessors were sufficiently inexpensive that a single person could have all the CPU time dedicated solely to their needs, even when idle. However, the Internet brought the general concept of time-sharing back into popularity. Expensive corporate server farms costing millions can host thousands of customers all sharing the same common resources. As with the early serial terminals, web sites operate primarily in bursts of activity followed by periods of idle time. This bursting nature permits the service to be used by many customers at once, usually with no perceptible communication delays, unless the servers start to get very busy.


Time-sharing business

Genesis In the 1960s, several companies started providing time-sharing services as
service bureau A service bureau is a company that provides business services for a fee. The term has been extensively used to describe technology-based services to financial services companies, particularly banks. Service bureaus are a significant sector within t ...
s. Early systems used
Teletype Model 33 The Teletype Model 33 is an electromechanical teleprinter designed for light-duty office use. It is less rugged and cost less than earlier Teletype machines. The Teletype Corporation introduced the Model 33 as a commercial product in 1963 af ...
KSR or ASR or Teletype Model 35 KSR or ASR machines in
ASCII ASCII ( ), abbreviated from American Standard Code for Information Interchange, is a character encoding standard for electronic communication. ASCII codes represent text in computers, telecommunications equipment, and other devices. Because ...
environments, and IBM Selectric typewriter-based terminals (especially the IBM 2741) with two different seven-bit codes. They would connect to the central computer by dial-up Bell 103A modem or acoustically coupled
modem A modulator-demodulator or modem is a computer hardware device that converts data from a digital format into a format suitable for an analog transmission medium such as telephone or radio. A modem transmits data by modulating one or more c ...
s operating at 10–15 characters per second. Later terminals and modems supported 30–120 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 Digital Equipment Corporation (DEC)'s PDP-10, later marketed as the DECsystem-10, is a mainframe computer family manufactured beginning in 1966 and discontinued in 1983. 1970s models and beyond were marketed under the DECsystem-10 name, espec ...
, the IBM 360, and the GE-600 series. Companies providing this service included GE's GEISCO, the IBM subsidiary The Service Bureau Corporation, Tymshare (founded in 1966),
National CSS National CSS, Inc. (NCSS) was a time-sharing firm in the 1960–80s, until its acquisition by Dun & Bradstreet in 1979. NCSS was originally headquartered in Norwalk, Connecticut, but relocated to Wilton in 1978. Sales offices, data centers, and de ...
(founded in 1967 and bought by Dun & Bradstreet in 1979), Dial Data (bought by Tymshare in 1968),
Bolt, Beranek, and Newman Raytheon BBN (originally Bolt Beranek and Newman Inc.) is an American research and development company, based next to Fresh Pond in Cambridge, Massachusetts, United States. In 1966, the Franklin Institute awarded the firm the Frank P. Brown ...
(BBN) and Time Sharing Ltd. in the UK. By 1968, there were 32 such service bureaus serving the US
National Institutes of Health The National Institutes of Health, commonly referred to as NIH (with each letter pronounced individually), is the primary agency of the United States government responsible for biomedical and public health research. It was founded in the lat ...
(NIH) alone. The ''Auerbach Guide to Timesharing'' (1973) lists 125 different timesharing services using equipment from Burroughs,
CDC The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georg ...
, DEC, HP,
Honeywell Honeywell International Inc. is an American publicly traded, multinational conglomerate corporation headquartered in Charlotte, North Carolina. It primarily operates in four areas of business: aerospace, building technologies, performance ma ...
, IBM, RCA, Univac, and XDS.


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." For DEC, for a while the second largest computer company (after IBM), this was also true: Their
PDP-10 Digital Equipment Corporation (DEC)'s PDP-10, later marketed as the DECsystem-10, is a mainframe computer family manufactured beginning in 1966 and discontinued in 1983. 1970s models and beyond were marketed under the DECsystem-10 name, espec ...
and IBM's 360/67 were widely used by commercial timesharing services such as CompuServe, On-Line Systems, Inc. (OLS), Rapidata and Time Sharing Ltd. The advent of the
personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or te ...
marked the beginning of the decline of time-sharing. 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..


=Rapidata as an example

= Although many time-sharing services simply closed, Rapidata held on, and became part of National Data Corporation. It was still of sufficient interest in 1982 to be the focus of "A User's Guide to Statistics Programs: The Rapidata Timesharing System". Even as revenue fell by 66% and National Data subsequently developed its own problems, attempts were made to keep this timesharing business going.


=UK

= * Time Sharing Limited (TSL, 1969-1974) - launched using DEC systems. PERT was one of its popular offerings. TSL was acquired by
ADP Adp or ADP may refer to: Aviation * Aéroports de Paris, airport authority for the Parisian region in France * Aeropuertos del Perú, airport operator for airports in northern Peru * SLAF Anuradhapura, an airport in Sri Lanka * Ampara Airp ...
in 1974. * OLS Computer Services (UK) Limited (1975-1980) - using HP & DEC systems.


The computer utility

Beginning in 1964, the
Multics Multics ("Multiplexed Information and Computing Service") is an influential early time-sharing operating system based on the concept of a single-level memory.Dennis M. Ritchie, "The Evolution of the Unix Time-sharing System", Communications of ...
operating system was designed as a
computing utility Utility computing or The Computer Utility is a service provisioning model in which a service provider makes computing resources and infrastructure management available to the customer as needed, and charges them for specific usage rather than a ...
, modeled on the electrical or telephone utilities. In the 1970s,
Ted Nelson Theodor Holm Nelson (born June 17, 1937) is an American pioneer of information technology, philosopher, and sociologist. He coined the terms ''hypertext'' and '' hypermedia'' in 1963 and published them in 1965. Nelson coined the terms '' trans ...
's original " Xanadu" hypertext repository was envisioned as such a service.


Security

Time-sharing was the first time that multiple
processes A process is a series or set of activities that interact to produce a result; it may occur once-only or be recurrent or periodic. Things called a process include: Business and management *Business process, activities that produce a specific se ...
, owned by different users, were running on a single machine, and these processes could interfere with one another. For example, one process might alter shared resources which another process relied on, such as a variable stored in memory. When only one user was using the system, this would result in possibly wrong output - but with multiple users, this might mean that other users got to see information they were not meant to see. To prevent this from happening, an operating system needed to enforce a set of policies that determined which privileges each process had. For example, the operating system might deny access to a certain variable by a certain process. The first international conference on computer security in London in 1971 was primarily driven by the time-sharing industry and its customers. Time-sharing in the form of shell accounts has been considered a risk.


Notable time-sharing systems

Significant early timesharing systems: * Allen-Babcock RUSH (Remote Users of Shared Hardware) Time-sharing System on IBM S/360 hardware (1966) → Tymshare *
AT&T AT&T Inc. is an American multinational telecommunications holding company headquartered at Whitacre Tower in Downtown Dallas, Texas. It is the world's largest telecommunications company by revenue and the third largest provider of mobile ...
Bell Labs Nokia Bell Labs, originally named Bell Telephone Laboratories (1925–1984), then AT&T Bell Laboratories (1984–1996) and Bell Labs Innovations (1996–2007), is an American industrial research and scientific development company owned by mul ...
Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, ...
(1971) → UC Berkeley
BSD Unix The Berkeley Software Distribution or Berkeley Standard Distribution (BSD) is a discontinued operating system based on Research Unix, developed and distributed by the Computer Systems Research Group (CSRG) at the University of California, Berke ...
(1977) * BBN PDP-1 Time-sharing System →
Massachusetts General Hospital Massachusetts General Hospital (Mass General or MGH) is the original and largest teaching hospital of Harvard Medical School located in the West End neighborhood of Boston, Massachusetts. It is the third oldest general hospital in the United Stat ...
PDP-1D → MUMPS * BBN TENEXDEC TOPS-20, Foonly FOONEX, MAXC OS at PARC, Stanford Low Overhead TimeSharing (LOTS), which ran TOPS-20 * Berkeley Timesharing System at UC Berkeley Project GenieScientific Data Systems SDS 940 ( Tymshare, BBN, SRI, Community Memory) → BCC 500 → MAXC at PARC * Burroughs Time-sharing MCPHP 3000 MPE * Cambridge Multiple Access System was developed for the
Titan Titan most often refers to: * Titan (moon), the largest moon of Saturn * Titans, a race of deities in Greek mythology Titan or Titans may also refer to: Arts and entertainment Fictional entities Fictional locations * Titan in fiction, fictiona ...
, the prototype
Atlas An atlas is a collection of maps; it is typically a bundle of maps of Earth or of a region of Earth. Atlases have traditionally been bound into book form, but today many atlases are in multimedia formats. In addition to presenting geogra ...
2 computer built by
Ferranti Ferranti or Ferranti International plc was a UK electrical engineering and equipment firm that operated for over a century from 1885 until it went bankrupt in 1993. The company was once a constituent of the FTSE 100 Index. The firm was known ...
for the
University of Cambridge , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...
. This was the first time-sharing system developed outside the United States, and which influenced the later development of
UNIX Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, ...
. * Compower Ltd., a wholly owned subsidiary of the National Coal Board (later British Coal Corporation) in the UK. Originally National Coal Board (NCB) Computer Services, it became Compower in 1973 providing computing and time-share services to internal NCB users and as a commercial service to external users. Sold to Philips C&P (Communications and Processing) in August 1994. * CompuServe, also branded as Compu-Serv, CIS. * Compu-Time, Inc., on
Honeywell Honeywell International Inc. is an American publicly traded, multinational conglomerate corporation headquartered in Charlotte, North Carolina. It primarily operates in four areas of business: aerospace, building technologies, performance ma ...
400/4000, started in 1968 in Ft Lauderdale, Florida, moved to Daytona Beach in 1970. *
CDC The Centers for Disease Control and Prevention (CDC) is the national public health agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georg ...
MACE, APEX → KronosNOSNOS/VE * Dartmouth Time Sharing System (DTSS) → GE Time-sharing → GEnie * DEC
PDP-6 The PDP-6, short for Programmed Data Processor model 6, is a computer developed by Digital Equipment Corporation (DEC) during 1963 and first delivered in the summer of 1964. It was an expansion of DEC's existing 18-bit systems to use a 36-bit d ...
Time-sharing Monitor →
TOPS-10 TOPS-10 System (''Timesharing / Total Operating System-10'') is a discontinued operating system from Digital Equipment Corporation (DEC) for the PDP-10 (or DECsystem-10) mainframe computer family. Launched in 1967, TOPS-10 evolved from the earlie ...
BBN TENEX → DEC TOPS-20 * DEC TSS/8RSTS-11, RSX-11
OpenVMS OpenVMS, often referred to as just VMS, is a multi-user, multiprocessing and virtual memory-based operating system. It is designed to support time-sharing, batch processing, transaction processing and workstation applications. Customers using Ope ...
*
English Electric KDF9 KDF9 was an early British 48-bit computer designed and built by English Electric (which in 1968 was merged into International Computers Limited (ICL)). The first machine came into service in 1964 and the last of 29 machines was decommissioned ...
COTAN (Culham Online Task Activation Network) * HP 2000 Time-Shared BASIC * HP 3000 series * IBM CALL/360, CALL/OS - using
IBM System/360 Model 50 The IBM System/360 Model 50 is a member of the IBM System/360 family of computers. The Model 50 was announced in April 1964 with the other initial models of the family, and first shipped in August 1965 to the Bank of America. Models There are f ...
* IBM CP-40CP-67CP-370
CP/CMS CP/CMS (Control Program/Cambridge Monitor System) is a discontinued time-sharing operating system of the late 1960s and early 1970s, known for its excellent performance and advanced features. It had three distinct versions: * CP-40/CMS, an ...
VM/CMS VM (often: VM/CMS) is a family of IBM virtual machine operating systems used on IBM mainframes System/370, System/390, zSeries, System z and compatible systems, including the Hercules emulator for personal computers. The following ver ...
* IBM TSO for OS/MVT → for OS/VS2 → for MVS → for z/OS * IBM
TSS/360 The IBM Time Sharing System TSS/360 is a discontinued early time-sharing operating system designed exclusively for a special model of the System/360 line of mainframes, the Model 67. Made available on a trial basis to a limited set of cust ...
→ TSS/370 * ICT 1900 series
GEORGE 3 GEORGE was the name given to a series of operating systems released by International Computers and Tabulators (ICT) in the 1960s, for the ICT 1900 series of computers. These included GEORGE 1, GEORGE 2, GEORGE 3, and GEORGE 4. Initially the ...
MOP (Multiple Online Programming) * International Timesharing Corporation on dual CDC 3300 systems. * MIT CTSS
MULTICS Multics ("Multiplexed Information and Computing Service") is an influential early time-sharing operating system based on the concept of a single-level memory.Dennis M. Ritchie, "The Evolution of the Unix Time-sharing System", Communications of ...
(MIT / GE / Bell Labs) →
Unix Unix (; trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, whose development started in 1969 at the Bell Labs research center by Ken Thompson, Dennis Ritchie, ...
* MIT Time-sharing System for the DEC PDP-1ITS *
McGill University McGill University (french: link=no, Université McGill) is an English-language public research university located in Montreal, Quebec, Canada. Founded in 1821 by royal charter granted by King George IV,Frost, Stanley Brice. ''McGill Univer ...
MUSIC → IBM
MUSIC/SP ''MUSIC/SP (Multi-User System for Interactive Computing/System Product''; originally "McGill University System for Interactive Computing") was developed at McGill University in the 1970s from an early IBM time-sharing system called RAX ( Re ...
*
Michigan Terminal System The Michigan Terminal System (MTS) is one of the first time-sharing computer operating systems.. Developed in 1967 at the University of Michigan for use on IBM S/360-67, S/370 and compatible mainframe computers, it was developed and used by a ...
, on the IBM S/360-67, S/370, and successors. *
Michigan State University Michigan State University (Michigan State, MSU) is a public land-grant research university in East Lansing, Michigan. It was founded in 1855 as the Agricultural College of the State of Michigan, the first of its kind in the United States. It ...
CDC SCOPE/HUSTLER System *
National CSS National CSS, Inc. (NCSS) was a time-sharing firm in the 1960–80s, until its acquisition by Dun & Bradstreet in 1979. NCSS was originally headquartered in Norwalk, Connecticut, but relocated to Wilton in 1978. Sales offices, data centers, and de ...
VP/CSS VP/CSS was a time-sharing operating system developed by National CSS. It began life in 1968 as a copy of IBM's CP/CMS, which at the time was distributed to IBM customers at no charge, in source code form, without support, as part of the IBM Type ...
, on IBM 360 series; originally based on IBM's
CP/CMS CP/CMS (Control Program/Cambridge Monitor System) is a discontinued time-sharing operating system of the late 1960s and early 1970s, known for its excellent performance and advanced features. It had three distinct versions: * CP-40/CMS, an ...
. *
Oregon State University Oregon State University (OSU) is a public land-grant, research university in Corvallis, Oregon. OSU offers more than 200 undergraduate-degree programs along with a variety of graduate and doctoral degrees. It has the 10th largest engineering ...
OS-3, on CDC 3000 series. * Prime Computer
PRIMOS PRIMOS is a discontinued operating system developed during the 1970s by Prime Computer for its minicomputer systems. It rapidly gained popularity and by the mid-1980s was a serious contender as a mainline minicomputer operating system. With ...
* RAND JOSS → JOSS-2 → JOSS-3 * RCA TSOSUnivac / Unisys VMOS →
VS/9 VS/9 is a computer operating system for the UNIVAC Series 90 mainframes (90/60, 90/70, and 90/80), used during the late 1960s through 1980s. The 90/60 and 90/70 were repackaged Univac 9700 computers. After the RCA acquisition by Sperry, i ...
* Service in Informatics and Analysis (SIA), on CDC 6600 Kronos. * System Development Corporation Time-sharing System, on the
AN/FSQ-32 The AN/FSQ-32 SAGE Solid State Computer (AN/FSQ-7A before December 1958, colloq. "Q-32") was a planned military computer central for deployment to Super Combat Centers in nuclear bunkers and to some above-ground military installations. In 1958, ...
. * Stanford ORVYL and WYLBUR, on IBM S/360-67. * Stanford PDP-1 Time-sharing System →
SAIL A sail is a tensile structure—which is made from fabric or other membrane materials—that uses wind power to propel sailing craft, including sailing ships, sailboats, windsurfers, ice boats, and even sail-powered land vehicles. Sails ma ...
WAITS * Time Sharing Ltd. (TSL) on DEC
PDP-10 Digital Equipment Corporation (DEC)'s PDP-10, later marketed as the DECsystem-10, is a mainframe computer family manufactured beginning in 1966 and discontinued in 1983. 1970s models and beyond were marketed under the DECsystem-10 name, espec ...
systems → Automatic Data Processing (ADP), first commercial time-sharing system in Europe and first dual (fault tolerant) time-sharing system. * Tone (TSO-like, for VS1), a non-IBM Time-sharing product, marketed by Tone Software Co; TSO required VS2. * Tymshare SDS-940 → Tymcom X → Tymcom XX * Unisys/ UNIVAC 1108 EXEC 8 → OS 1100 →
OS 2200 OS 2200 is the operating system for the Unisys ClearPath Dorado family of mainframe systems. The operating system kernel of OS 2200 is a lineal descendant of Exec 8 for the UNIVAC 1108. Documentation and other information on current and past Un ...
* UC Berkeley CAL-TSS, on CDC 6400. * XDS UTSCP-VHoneywell CP-6


See also

*
Cloud computing Cloud computing is the on-demand availability of computer system resources, especially data storage ( cloud storage) and computing power, without direct active management by the user. Large clouds often have functions distributed over mu ...
* The Heralds of Resource Sharing, a 1972 film. * History of CP/CMS, IBM's virtual machine operating system (CP) that supported time-sharing (CMS). * IBM M44/44X, an experimental computer system based on an
IBM 7044 The IBM 7040 was a historic but short-lived model of transistor computer built in the 1960s. History It was announced by IBM in December 1961, but did not ship until April 1963. A later member of the IBM 700/7000 series of scientific compute ...
used to simulate multiple virtual machines. * IBM System/360 Model 67, the only IBM S/360 series mainframe to support virtual memory. *
Multiseat configuration A multiseat, multi-station or multiterminal system is a single computer which supports multiple independent local users at the same time. A "seat" consists of all hardware devices assigned to a specific workplace at which one user sits at and ...
, multiple users on a single
personal computer A personal computer (PC) is a multi-purpose microcomputer whose size, capabilities, and price make it feasible for individual use. Personal computers are intended to be operated directly by an end user, rather than by a computer expert or te ...
. * Project MAC, a
DARPA The Defense Advanced Research Projects Agency (DARPA) is a research and development agency of the United States Department of Defense responsible for the development of emerging technologies for use by the military. Originally known as the A ...
funded project at MIT famous for groundbreaking research in
operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...
s,
artificial intelligence Artificial intelligence (AI) is intelligence—perceiving, synthesizing, and inferring information—demonstrated by machines, as opposed to intelligence displayed by animals and humans. Example tasks in which this is done include speech ...
, and the theory of computation. *
TELCOMP TELCOMP was a programming language developed at Bolt, Beranek and Newman (BBN) in about 1964 and in use until at least 1974. BBN offered TELCOMP as a paid service, with first revenue in October 1965. The service was sold to On-Line Systems, Inc ...
, an interactive, conversational programming language based on JOSS, developed by BBN in 1964. * Timeline of operating systems * VAX (Virtual Address eXtension), a computer architecture and family of computers developed by DEC. * Utility computing *
Virtual memory In computing, virtual memory, or virtual storage is a memory management technique that provides an "idealized abstraction of the storage resources that are actually available on a given machine" which "creates the illusion to users of a very ...
*
Time-sharing system evolution This article covers the evolution of time-sharing systems, providing links to major early time-sharing operating systems, showing their subsequent evolution. Time-sharing Time-sharing was first proposed in the mid- to late-1950s and first impleme ...


References


Further reading

* Nelson, Theodor (1974). ''Computer Lib: You Can and Must Understand Computers Now''; ''Dream Machines'': "New Freedoms Through Computer Screens— A Minority Report". Self-published. . pp. 56–57. *: "The author relates a short history of time-sharing, the initial time-sharing experiments, the modifications of existing computers and those designed specifically for time-sharing, project MAC, significant features of the system, services, languages, programs, scope displays and light pens, and intercommunication.


External links


"Time Sharing Supervisor Programs"
notes comparing the supervisor programs of CP-67,
TSS/360 The IBM Time Sharing System TSS/360 is a discontinued early time-sharing operating system designed exclusively for a special model of the System/360 line of mainframes, the Model 67. Made available on a trial basis to a limited set of cust ...
, the
Michigan Terminal System The Michigan Terminal System (MTS) is one of the first time-sharing computer operating systems.. Developed in 1967 at the University of Michigan for use on IBM S/360-67, S/370 and compatible mainframe computers, it was developed and used by a ...
(MTS), and
Multics Multics ("Multiplexed Information and Computing Service") is an influential early time-sharing operating system based on the concept of a single-level memory.Dennis M. Ritchie, "The Evolution of the Unix Time-sharing System", Communications of ...
by Michael T. Alexander, ''Advanced Topics in Systems Programming'' (1970, revised 1971), University of Michigan Engineering Summer Conference.
"The Computer Utility As A Marketplace For Computer Services"
Robert Frankston's MIT Master's Thesis, 1973.
"40 years of Multics, 1969-2009"
an interview with Professor Fernando J. Corbató on the history of
Multics Multics ("Multiplexed Information and Computing Service") is an influential early time-sharing operating system based on the concept of a single-level memory.Dennis M. Ritchie, "The Evolution of the Unix Time-sharing System", Communications of ...
and origins of time-sharing, 2009.
"Mainframe Computers: The Virtues of Sharing"
Revolution: The First 2000 Years of Computing, Computer History Museum Exhibition, January 2011.
"Mainframe Computers: Timesharing as a Business"
Revolution: The First 2000 Years of Computing, Computer History Museum Exhibition, January 2011. {{Authority control Operating system technology Computer systems