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{{Short description|Machine designed to support time-sharing}}
{{Infobox information appliance
{{Infobox information appliance
|image = <!--[[File:SDS 940_computer.jpg|300px|Hardware]] http://www.computerhistory.org/collections/catalog/102669852-->
|image = <!--[[File:SDS 940_computer.jpg|300px|Hardware]] http://www.computerhistory.org/collections/catalog/102669852-->
|type = [[Mainframe computer]]
|type = [[Mainframe computer]]
|release date = {{Start date and age|1966}}
|introduced = 1965
|releasedate =
|releasedate =
|discontinued =
|discontinued =
|cpu = [[Transistor computer|Transistor]]<ref>{{cite book |last1=Laws |first1=United States Congress Senate Committee on the Judiciary Subcommittee to Investigate the Administration of the Internal Security Act and Other Internal Security |title=Terroristic Activity: Hearings Before the Subcommittee to Investigate the Administration of the Internal Security Act and Other Internal Security Laws of the Committee on the Judiciary, United States Senate, Ninety-third Congress, Second Session ... |date=1975 |publisher=U.S. Government Printing Office |page=513 |url=https://books.google.com/books?id=hNZNk-HAShgC&q=%22XDS-940+computer+is+a+second+generation+computer%22 |language=en|quote=(...) XDS-940 computer is a second generation computer (...)}}</ref> based custom 24-bit CPU
|cpu = Integrated circuits based custom 24-bit CPU
|memory = 16 and 64 kilowords of 24 bits + parity, additional {{nowrap|4.5 MByte}} swap<ref name=stan68/>
|memory = 16 and 64 kilowords of 24 bits + parity, additional 4.5&nbsp;MB swap<ref name=stan68/>
|graphics = Instructions of beam motion, character writing, etc, 20 characters per second. 1000 character terminals with 875 line screen.<ref name=stan68/>
|graphics = Instructions of beam motion, character writing, etc, 20 characters per second. 1000-character terminals with 875-line screen.<ref name=stan68/>
|sound =
|sound =
|connectivity = Paper tape, line printer, modem
|connectivity = Paper tape, line printer, modem
|storage = 96 MByte at 117 kByte/s<!--(24*40000)/(8*1024)-->, {{nowrap|[[Hard disk drive performance characteristics#Access time|access time]]}} {{nowrap|85 ms}}<ref name=stan68/>
|storage = 96&nbsp;MB at 117&nbsp;kB/s<!--(24*40000)/(8*1024)-->, [[Hard disk drive performance characteristics#Access time|access&nbsp;time]] 85&nbsp;ms<ref name=stan68/>
|os = [[Berkeley Timesharing System]]
|os = SDS 940 Time-Sharing System, originally the [[Berkeley Timesharing System]]
|unitssold = 60
|unitssold = 60
|price = <!--{{USD|....}} (approx. ${{Inflation|US|....|1965|r=-2|fmt=c}} today)-->
|price = <!--{{USD|....}} (approx. ${{Inflation|US|....|1965|r=-2|fmt=c}} today)-->
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|successor =
|successor =
}}
}}
The '''SDS 940''' was [[Scientific Data Systems]]' (SDS) first machine designed to directly support [[time-sharing]]. The 940 was based on the [[SDS 930]]'s [[24-bit]] [[Central processing unit|CPU]], with additional circuitry to provide [[protected memory]] and [[virtual memory]].


The '''SDS 940''' was [[Scientific Data Systems]]' (SDS) first machine designed to support [[time-sharing]] directly, and was based on the [[SDS 930]]'s [[24-bit]] [[Central processing unit|CPU]] built primarily of discrete transistors. It was announced in February 1966 and shipped in April, becoming a major part of [[Tymshare]]'s expansion during the 1960s. The influential [[SRI International|Stanford Research Institute]] [[NLS (computer system)|"oN-Line System"]] (NLS) was demonstrated on the system.
It was announced in February 1966 and shipped in April, becoming a major part of [[Tymshare]]'s expansion during the 1960s. The influential [[SRI International|Stanford Research Institute]] [[NLS (computer system)|"oN-Line System"]] (NLS) was demonstrated on the system. This machine was later used to run [[Community Memory]], the first [[bulletin board system]].


After SDS was acquired by [[Xerox]] in 1969 and became Xerox Data Systems, the SDS 940 was renamed as the '''XDS 940'''.
After SDS was acquired by [[Xerox]] in 1969 and became Xerox Data Systems, the SDS 940 was renamed as the '''XDS 940'''.


==History==
==History==
The design was originally created by the [[University of California, Berkeley]] as part of their [[Project Genie]] that ran between 1964 and 1965. Genie added [[memory management]] and controller logic to an existing [[SDS 930]] computer to give it [[Page (computer memory)|page-mapped]] [[virtual memory]], which would be heavily copied by other designs. The 940 was simply a commercialized version of the Genie design, and remained backwardly compatible with their earlier models, with the exception of the 12-bit [[SDS 92]].
The design was originally created by the [[University of California, Berkeley]] as part of their [[Project Genie]] that ran between 1964 and 1969. Genie added [[memory management]] and controller logic to an existing [[SDS 930]] computer to give it [[Page (computer memory)|page-mapped]] [[virtual memory]], which would be heavily copied by other designs. The 940 was simply a commercialized version of the Genie design and remained backwardly compatible with their earlier models, with the exception of the 12-bit [[SDS 92]].


Like most systems of the era, the machine was built with a bank of [[core memory]] as the primary storage, allowing between 16 and 64 kilowords. Words were [[24 bit]]s plus a [[parity bit]].<ref name="to"/> This was backed up by a variety of secondary storage devices, including a 1376 kWord drum in Genie, or [[hard disk]]s in the SDS models in the form of a drum-like 2097 kWord ‘fixed head’ disk or a 16 384 kWord traditional ‘floating head’ model. The SDS machines also included a [[paper tape]] punch and reader, [[line printer]], and a real-time clock. They [[booting|bootstrapped]] from paper tape.
Like most systems of the era, the machine was built with a bank of [[core memory]] as the primary storage, allowing between 16 and 64 kilowords. Words were [[24 bit]]s plus a [[parity bit]].<ref name="to"/> This was backed up by a variety of secondary storage devices, including a 1376 kword drum in Genie, or [[hard disk]]s in the SDS models in the form of a drum-like 2097 kword "fixed-head" disk or a {{val|16384|u=kword}} traditional "floating-head" model. The SDS machines also included a [[paper tape]] punch and reader, [[line printer]], and a real-time clock. They [[booting|bootstrapped]] from paper tape.


A file storage of 96 MByte were also attached. The [[line printer]] used was a Potter Model HSP-3502 chain printer with 96 printing characters and a speed of about 230 lines per minute.<ref name=stan68>{{cite web
A file storage of 96&nbsp;MB were also attached. The [[line printer]] used was a Potter Model HSP-3502 chain printer with 96 printing characters and a speed of about 230 lines per minute.<ref name=stan68>{{cite web
|title=A research center for augmenting human intellect
|title=A research center for augmenting human intellect
|date=December 1968
|date=December 1968
|accessdate=2016-04-19
|access-date=2016-04-19
|url=https://web.stanford.edu/dept/SUL/library/extra4/sloan/mousesite/Archive/ResearchCenter1968/ResearchCenter1968.html}}</ref>
|url=https://web.stanford.edu/dept/SUL/library/extra4/sloan/mousesite/Archive/ResearchCenter1968/ResearchCenter1968.html
|archive-date=2020-02-20
|archive-url=https://web.archive.org/web/20200220043259/https://web.stanford.edu/dept/SUL/library/extra4/sloan/mousesite/Archive/ResearchCenter1968/ResearchCenter1968.html
|url-status=dead
}}</ref>


==Software System==
==Software system==
The [[operating system]] developed at Project Genie was the [[Berkeley Timesharing System]].<ref name="to">{{cite book |title= SDS 940 Time-Sharing System Technical Manual |work= SDS 90 11 16A |date= November 1967 |publisher= Scientific Data Systems |location= Santa Monica, California |url= http://bitsavers.org/pdf/sds/9xx/940/901116A_940_TimesharingTechMan_Nov67.pdf }}</ref>
The [[operating system]] developed at Project Genie was the [[Berkeley Timesharing System]].<ref name="to">{{cite book |title= SDS 940 Time-Sharing System Technical Manual |work= SDS 90 11 16A |date= November 1967 |publisher= Scientific Data Systems |location= Santa Monica, California |url= http://bitsavers.org/pdf/sds/9xx/940/901116A_940_TimesharingTechMan_Nov67.pdf }}</ref>
By August 1968 a version 2.0 was announced that was just called the "SDS 940 Time-Sharing System".<ref name="soft68">{{cite book |title= SDS 940 Time-Sharing System (Version 2.0) Technical Manual |work= SDS 90 11 16B |date= August 1968 |publisher= Scientific Data Systems |location= Santa Monica, California |url= http://bitsavers.org/pdf/sds/9xx/940/901116B_940_TimesharingTechMan_Aug68.pdf }}</ref>
By August 1968 a version 2.0 was announced that was just called the "SDS 940 Time-Sharing System".<ref name="soft68">{{cite book |title= SDS 940 Time-Sharing System (Version 2.0) Technical Manual |work= SDS 90 11 16B |date= August 1968 |publisher= Scientific Data Systems |location= Santa Monica, California |url= http://bitsavers.org/pdf/sds/9xx/940/901116B_940_TimesharingTechMan_Aug68.pdf }}</ref>
As of 1969, the XDS 940 Software System consisted of the following:
As of 1969, the XDS 940 software system consisted of the following:
* Time-Sharing Monitor (what is now usually called a [[kernel (computing)|kernel]])<ref name="soft68"/>
* Time-Sharing Monitor (what is now usually called a [[kernel (operating system)|kernel]])<ref name="soft68"/>
* Time-Sharing Executive (what is now usually called a [[command-line interface]])<ref name="soft68"/>
* Time-Sharing Executive (what is now usually called a [[command-line interface]])<ref name="soft68"/>
* [[CAL (Joss family)|CAL]], the Conversational Algebraic Language<ref>Butler Lampson (but without attribution), [https://archive.org/stream/bitsavers_sds9xx9409un67_2820101/901114A_940_CAL_RefMan_Jun67#page/n1/mode/1up CAL Reference Manual for SDS 940 Time-Sharing Computer System], Scientific Data Systems, June 1967.</ref>
* [[CAL (programming language)|CAL]], the Conversational Algebraic Language<ref>Butler Lampson (but without attribution), [https://archive.org/stream/bitsavers_sds9xx9409un67_2820101/901114A_940_CAL_RefMan_Jun67#page/n1/mode/1up CAL Reference Manual for SDS 940 Time-Sharing Computer System], Scientific Data Systems, June 1967.</ref>
* [[QED (text editor)|QED]], a text editor<ref>(without attribution), [https://archive.org/stream/bitsavers_sds9xx9409an69_1668444/901112B_940_QED_RefMan_Jan69#page/n1/mode/1up QED Reference Manual for SDS 940 Time-Sharing Computer Systems], Preliminary Edition, Scientific Data Systems, Jan. 1969.</ref>
* [[QED (text editor)|QED]], a text editor<ref>(without attribution), [https://archive.org/stream/bitsavers_sds9xx9409an69_1668444/901112B_940_QED_RefMan_Jan69#page/n1/mode/1up QED Reference Manual for SDS 940 Time-Sharing Computer Systems], Preliminary Edition, Scientific Data Systems, Jan. 1969.</ref>
* [[Fortran IV]]
* [[Fortran IV]]
* [[BASIC]]
* [[BASIC]]


The minimum configuration required to run the Software System included (partial list):
The minimal configuration required to run the Software System included (partial list):
* Two 16k-word core memory modules (with multiple access)".<ref name="soft68op">{{cite book |title= SDS 940 Theory of Operation Technical Manual |work= SDS 98 01 26A |date= March 1967 |publisher= Scientific Data Systems |location= Santa Monica, California |url= http://bitsavers.org/pdf/sds/9xx/980126A_940_TheoryOfOperation_Mar67.pdf }}</ref>
* Two 16-kword core-memory modules (with multiple access).<ref name="soft68op">{{cite book |title= SDS 940 Theory of Operation Technical Manual |work= SDS 98 01 26A |date= March 1967 |publisher= Scientific Data Systems |location= Santa Monica, California |url= http://bitsavers.org/pdf/sds/9xx/980126A_940_TheoryOfOperation_Mar67.pdf }}</ref>
* Two rapid-access disc (RAD) storage units and couplers (just under 4M character capacity each); optionally two more could be connected
* Two rapid-access disc (RAD) storage units and couplers (just under 4M character capacity each); optionally two more could be connected
* [[disk drive|Disc file]] and coupler, with 67M characters of storage
* [[disk drive|Disc file]] and coupler, with 67M characters of storage
* [[Magnetic tape]] control unit and two magnetic tape transports (controller supports up to 8)
* [[Magnetic tape]] control unit and two magnetic-tape transports (controller supports up to 8)
* [[Asynchronous communication]] controller(s), supporting up to 64 [[teletypewriter]] lines each
* [[Asynchronous communication]] controller(s), supporting up to 64 [[teletypewriter]] lines each


Additional software was available from the XDS Users' Group Library, such as a [[string (computer science)|string]] processing system, "SYSPOPs" (system programmed operators, which allow access to system services), [[CAL (Joss family)|CAL]] (Conversational Algebraic Language, a dialect of [[JOSS]]), [[QED (text editor)|QED]] (a text editor), TAP (Time-sharing Assembly Program, an [[Assembly language#Assembler|assembler]]), and [[Dynamic debugging technique|DDT]], a debugging tool.
Additional software was available from the XDS Users' Group Library, such as a [[string (computer science)|string]]-processing system, "SYSPOPs" (system programmed operators, which allow access to system services), [[CAL (Joss family)|CAL]] (Conversational Algebraic Language, a dialect of [[JOSS]]), [[QED (text editor)|QED]] (a text editor), TAP (Time-sharing Assembly Program, an [[Assembly language#Assembler|assembler]]), and [[Dynamic debugging technique|DDT]], a debugging tool.


A [[cathode ray tube]] display with 26 lines that operated DDT loader-[[debugger]] that were originally designed to operate from a [[Teleprinter|teletype terminal]] were also available.<ref name=stan68/>
A [[cathode-ray tube]] display with 26 lines that operated DDT loader-[[debugger]] that were originally designed to operate from a [[Teleprinter|teletype terminal]] were also available.<ref name=stan68/>


==Notable installations==
==Notable installations==
[[Butler Lampson]] estimated about 60 of the machines were sold.<ref>{{cite web |title=Systems |author= [[Butler Lampson]] |publisher= Microsoft Research |url= http://research.microsoft.com/en-us/um/people/blampson/Systems.html#SDS940 |accessdate= April 16, 2011 }}</ref>
[[Butler Lampson]] estimated that about 60 of the machines were sold.<ref>{{cite web |title=Systems |author= Butler Lampson |author-link= Butler Lampson |publisher= Microsoft Research |url= http://research.microsoft.com/en-us/um/people/blampson/Systems.html#SDS940 |access-date= April 16, 2011 }}</ref>

The major customer was [[Tymshare]], who used the system to become the USA's best known commercial timesharing service in the late 1960s. By 1972 Tymshare alone had 23 systems in operation.<ref>{{cite web |title= Timesharing as a Business |publisher= [[Computer History Museum]] |url= http://www.computerhistory.org/revolution/mainframe-computers/7/181 |accessdate= April 17, 2011 }} (includes pictures)</ref>
* The major customer was [[Tymshare]], who used the system to become the USA's best known commercial timesharing service in the late 1960s. By 1972 Tymshare alone had 23 systems in operation.<ref>{{cite web |title= Timesharing as a Business |publisher= [[Computer History Museum]] |url= http://www.computerhistory.org/revolution/mainframe-computers/7/181 |access-date= April 17, 2011 }} (includes pictures)</ref>
[[Comshare]], Inc, of [[Ann Arbor, Michigan]], was the second most important corporate customer; Tymshare, Comshare and [[UC Berkeley]] collaborated in much of the operating system development for the SDS 940. [[Douglas Engelbart]]'s [[Augmentation Research Center]] (ARC) used an SDS 940 for their [[NLS (computer system)|oN-Line System]], more commonly known as NLS.<ref>{{cite book
* [[Comshare]], Inc, of [[Ann Arbor, Michigan]], was the second most important corporate customer. Tymshare, Comshare and [[UC Berkeley]] collaborated in much of the operating system development for the SDS 940.
* [[Douglas Engelbart]]'s [[Augmentation Research Center]] (ARC) used an SDS 940 for their [[NLS (computer system)|oN-Line System]], more commonly known as NLS.<ref>{{cite book
| last = Markoff
| last = Markoff
| first = John
| first = John
Line 67: Line 75:
| isbn = 978-1-1012-0108-4
| isbn = 978-1-1012-0108-4
| edition = E-book
| edition = E-book
| ref = harv
| page = 240
| page = 240
| chapter = 5 Dealing Lightning With Both Hands
| chapter = 5 Dealing Lightning With Both Hands
| quote = E-book pages are approximate due device and fonts used
| quote = E-book pages are approximate due device and fonts used
}} </ref> It was with this computer that he gave [[The Mother of All Demos]] in December 1968, heralding many of the concepts associated with personal computing today.<ref>{{cite news
}}</ref> It was with this computer that he gave [[The Mother of All Demos]] in December 1968, heralding many of the concepts associated with personal computing today.<ref>{{cite news
| last = Metz
|last = Metz
| first = Cade
|first = Cade
| url = http://www.theregister.co.uk/2008/12/11/engelbart_celebration/
|url = https://www.theregister.co.uk/2008/12/11/engelbart_celebration/
| title = The Mother of All Demos — 150 years ahead of its time
|title = The Mother of All Demos — 150 years ahead of its time
| date = 2008-12-11
|date = 2008-12-11
| work = The Register
|work = The Register
| accessdate = 2011-01-24
|access-date = 2011-01-24
| location = London
|location = London
|archive-url = https://web.archive.org/web/20131203033009/http://www.theregister.co.uk/2008/12/11/engelbart_celebration/

|archive-date = 2013-12-03
| archiveurl = http://www.webcitation.org/6LfrMpwxt
|url-status = live
| archivedate = 2013-12-06
}}</ref>
| deadurl = no
⚫
* The first host connected to the [[ARPANET]] was an SDS 940 at [[SRI International|SRI]] in October, 1969.<ref>{{cite web |last1=Crandall |first1=Rick |title=SDS 940 Timesharing Computer |url=http://rickcrandall.net/article3.php |website=Rick Crandall |access-date=23 December 2015 |url-status=dead |archive-url=https://web.archive.org/web/20151224104328/http://rickcrandall.net/article3.php |archive-date=24 December 2015 }}</ref>
| ref = harv
⚫
* A [[San Francisco]] counterculture community action group called Resource One and located in ''Project One'' used a donated surplus XDS 940 as described in ''[[Rolling Stone]]'' magazine in 1972.<ref>{{cite magazine |title= Spacewar: Fanatic Life and Symbolic Death Among the Computer Bums |author= Stewart Brand |author-link= Stewart Brand |magazine= [[Rolling Stone]] |date= December 7, 1972 |url= http://www.wheels.org/spacewar/stone/rolling_stone.html |access-date= April 16, 2011}}</ref>
⚫
}}</ref> The first host connected to the [[ARPANET]] was an SDS 940 at [[SRI International|SRI]] in October, 1969.<ref>{{cite web|last1=Crandall|first1=Rick|title=SDS 940 Timesharing Computer|url=http://rickcrandall.net/article3.php|website=Rick Crandall|accessdate=23 December 2015}}</ref>
⚫
* The [[Community Memory]] project served as an early electronic [[bulletin board system]].<ref>{{cite web |title= Community Memory: 1972–1974, Berkeley and San Francisco, California |publisher= [[The WELL]]: Whole Earth 'Lectronic Link |url= http://www.well.com/~szpak/cm/index.html |access-date= April 17, 2011 |archive-date= November 17, 2016 |archive-url= https://web.archive.org/web/20161117031011/http://www.well.com/~szpak/cm/index.html |url-status= dead }}</ref>
⚫
A [[San Francisco]] counterculture community action group called Resource One and located in ''Project One'' used a donated surplus XDS 940 as described in ''[[Rolling Stone]]'' magazine in 1972.<ref>{{cite news |title= Spacewar: Fanatic Life and Symbolic Death Among the Computer Bums |author= [[Stewart Brand]] |work= [[Rolling Stone]] |date= December 7, 1972 |url= http://www.wheels.org/spacewar/stone/rolling_stone.html |accessdate= April 16, 2011}}</ref>
⚫
The [[Community Memory]] project served as an early electronic [[bulletin board system]].<ref>{{cite web |title= Community Memory: 1972 - 1974, Berkeley and San Francisco, California |publisher= [[The WELL]]: Whole Earth 'Lectronic Link |url= http://www.well.com/~szpak/cm/index.html |accessdate= April 17, 2011 }}</ref>


==See also==
==See also==
*[[SDS Sigma series]]
*[[SDS Sigma series]]
*[[SDS 9xx computers]]
*[[SDS 9 Series]]


==References==
==References==
Line 98: Line 104:
<!-- ==Further reading==
<!-- ==Further reading==
*[[Scientific Data Systems|Xerox Data Systems]], ''XDS 940 Computer'' (1969) what about it?? Is this a document? -->
*[[Scientific Data Systems|Xerox Data Systems]], ''XDS 940 Computer'' (1969) what about it?? Is this a document? -->

==External links==
==External links==
* {{cite web |title= SDS 940 Computer - console |publisher= [[Computer History Museum]] |url= http://www.computerhistory.org/revolution/mainframe-computers/7/181/730?position=0 |accessdate= April 17, 2011 }} (pictures)
* {{cite web |title= SDS 940 Computer - console |publisher= [[Computer History Museum]] |url= http://www.computerhistory.org/revolution/mainframe-computers/7/181/730?position=0 |access-date= April 17, 2011 }} (pictures)
*[http://bitsavers.org/bits/SDS/9xx/ Software archive]
*[http://bitsavers.org/bits/SDS/9xx/ Software archive]


[[Category:Mainframe computers]]
[[Category:Mainframe computers]]
[[Category:Scientific Data Systems computers]]
[[Category:Scientific Data Systems]]
[[Category:Time-sharing]]
[[Category:Time-sharing]]
[[Category:24-bit computers]]

Latest revision as of 16:59, 21 July 2023

SDS 940
TypeMainframe computer
Release date1966; 58 years ago (1966)
Units sold60
Operating systemSDS 940 Time-Sharing System, originally the Berkeley Timesharing System
CPUTransistor[1] based custom 24-bit CPU
Memory16 and 64 kilowords of 24 bits + parity, additional 4.5 MB swap[2]
Storage96 MB at 117 kB/s, access time 85 ms[2]
GraphicsInstructions of beam motion, character writing, etc, 20 characters per second. 1000-character terminals with 875-line screen.[2]
ConnectivityPaper tape, line printer, modem

The SDS 940 was Scientific Data Systems' (SDS) first machine designed to directly support time-sharing. The 940 was based on the SDS 930's 24-bit CPU, with additional circuitry to provide protected memory and virtual memory.

It was announced in February 1966 and shipped in April, becoming a major part of Tymshare's expansion during the 1960s. The influential Stanford Research Institute "oN-Line System" (NLS) was demonstrated on the system. This machine was later used to run Community Memory, the first bulletin board system.

After SDS was acquired by Xerox in 1969 and became Xerox Data Systems, the SDS 940 was renamed as the XDS 940.

History[edit]

The design was originally created by the University of California, Berkeley as part of their Project Genie that ran between 1964 and 1969. Genie added memory management and controller logic to an existing SDS 930 computer to give it page-mapped virtual memory, which would be heavily copied by other designs. The 940 was simply a commercialized version of the Genie design and remained backwardly compatible with their earlier models, with the exception of the 12-bit SDS 92.

Like most systems of the era, the machine was built with a bank of core memory as the primary storage, allowing between 16 and 64 kilowords. Words were 24 bits plus a parity bit.[3] This was backed up by a variety of secondary storage devices, including a 1376 kword drum in Genie, or hard disks in the SDS models in the form of a drum-like 2097 kword "fixed-head" disk or a 16384 kword traditional "floating-head" model. The SDS machines also included a paper tape punch and reader, line printer, and a real-time clock. They bootstrapped from paper tape.

A file storage of 96 MB were also attached. The line printer used was a Potter Model HSP-3502 chain printer with 96 printing characters and a speed of about 230 lines per minute.[2]

Software system[edit]

The operating system developed at Project Genie was the Berkeley Timesharing System.[3] By August 1968 a version 2.0 was announced that was just called the "SDS 940 Time-Sharing System".[4] As of 1969, the XDS 940 software system consisted of the following:

The minimal configuration required to run the Software System included (partial list):

  • Two 16-kword core-memory modules (with multiple access).[7]
  • Two rapid-access disc (RAD) storage units and couplers (just under 4M character capacity each); optionally two more could be connected
  • Disc file and coupler, with 67M characters of storage
  • Magnetic tape control unit and two magnetic-tape transports (controller supports up to 8)
  • Asynchronous communication controller(s), supporting up to 64 teletypewriter lines each

Additional software was available from the XDS Users' Group Library, such as a string-processing system, "SYSPOPs" (system programmed operators, which allow access to system services), CAL (Conversational Algebraic Language, a dialect of JOSS), QED (a text editor), TAP (Time-sharing Assembly Program, an assembler), and DDT, a debugging tool.

A cathode-ray tube display with 26 lines that operated DDT loader-debugger that were originally designed to operate from a teletype terminal were also available.[2]

Notable installations[edit]

Butler Lampson estimated that about 60 of the machines were sold.[8]

See also[edit]

References[edit]

  1. ^ Laws, United States Congress Senate Committee on the Judiciary Subcommittee to Investigate the Administration of the Internal Security Act and Other Internal Security (1975). Terroristic Activity: Hearings Before the Subcommittee to Investigate the Administration of the Internal Security Act and Other Internal Security Laws of the Committee on the Judiciary, United States Senate, Ninety-third Congress, Second Session ... U.S. Government Printing Office. p. 513. (...) XDS-940 computer is a second generation computer (...)
  2. ^ a b c d e "A research center for augmenting human intellect". December 1968. Archived from the original on 2020-02-20. Retrieved 2016-04-19.
  3. ^ a b SDS 940 Time-Sharing System Technical Manual (PDF). Santa Monica, California: Scientific Data Systems. November 1967. {{cite book}}: |work= ignored (help)
  4. ^ a b c SDS 940 Time-Sharing System (Version 2.0) Technical Manual (PDF). Santa Monica, California: Scientific Data Systems. August 1968. {{cite book}}: |work= ignored (help)
  5. ^ Butler Lampson (but without attribution), CAL Reference Manual for SDS 940 Time-Sharing Computer System, Scientific Data Systems, June 1967.
  6. ^ (without attribution), QED Reference Manual for SDS 940 Time-Sharing Computer Systems, Preliminary Edition, Scientific Data Systems, Jan. 1969.
  7. ^ SDS 940 Theory of Operation Technical Manual (PDF). Santa Monica, California: Scientific Data Systems. March 1967. {{cite book}}: |work= ignored (help)
  8. ^ Butler Lampson. "Systems". Microsoft Research. Retrieved April 16, 2011.
  9. ^ "Timesharing as a Business". Computer History Museum. Retrieved April 17, 2011. (includes pictures)
  10. ^ Markoff, John (2005). "5 Dealing Lightning With Both Hands". What the Dormouse Said: How the Sixties Counterculture Shaped the Personal Computer Industry (E-book ed.). New York: Penguin Group. p. 240. ISBN 978-1-1012-0108-4. E-book pages are approximate due device and fonts used
  11. ^ Metz, Cade (2008-12-11). "The Mother of All Demos — 150 years ahead of its time". The Register. London. Archived from the original on 2013-12-03. Retrieved 2011-01-24.
  12. ^ Crandall, Rick. "SDS 940 Timesharing Computer". Rick Crandall. Archived from the original on 24 December 2015. Retrieved 23 December 2015.
  13. ^ Stewart Brand (December 7, 1972). "Spacewar: Fanatic Life and Symbolic Death Among the Computer Bums". Rolling Stone. Retrieved April 16, 2011.
  14. ^ "Community Memory: 1972–1974, Berkeley and San Francisco, California". The WELL: Whole Earth 'Lectronic Link. Archived from the original on November 17, 2016. Retrieved April 17, 2011.


External links[edit]

Retrieved from "https://en.wikipedia.org/w/index.php?title=SDS_940&oldid=1166451127"