Editing CSIRAC

{{Short description|Australia's first digital computer, and the fifth stored-program computer in the world}}{{More citations needed|date=May 2025}}

{{Use dmy dates|date=June 2020}}
{{Use Australian English|date=August 2019}}
{{Infobox information appliance
| name = CSIRAC
| title = 
| aka = CSIR Mk 1
| logo = 
| image = CSIRAC-Pano,-Melb.-Museum,-12.8.2008.jpg
| caption = CSIRAC, Australia's first digital computer, as displayed at the [[Melbourne Museum]]
| developer = [[CSIRO]]
| manufacturer = 
| family = 
| type = [[Digital computer]]
| generation = 
| releasedate = c.{{Start date|1949}}
| lifespan = 
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| discontinued = 
| unitssold = 
| unitsshipped = 1
| media = 
| os = 
| power = 
| soc = 
| cpu = 
| memory = 
| storage = 
| memory card = 
| display = 
| graphics = 
| sound = 
| input = 
| controllers = 
| camera = 
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| service = 
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}}
'''CSIRAC''' ({{IPAc-en|ˈ|s|aɪ|r|æ|k}}; '''''C'''ommonwealth '''S'''cientific and '''I'''ndustrial '''R'''esearch '''A'''utomatic '''C'''omputer''), originally known as '''CSIR Mk 1''', was [[Australia]]'s first [[digital computer]], and the fifth [[stored-program computer]] in the world.<ref>{{cite web | url = https://cis.unimelb.edu.au/about/csirac | title = CSIRAC: Our first computer |website=School of Computing and Information Systems, [[University of Melbourne]] | date = 12 August 2021 }}</ref> It is the oldest surviving [[History of computing hardware#First-generation von Neumann machines|first-generation electronic computer]]<ref name=VHD/>
(the [[Z4 (computer)|Zuse Z4]] at the [[Deutsches Museum]] is older, but was [[Mechanical computer#Electro-mechanical computers|electro-mechanical]], not [[List of vacuum tube computers|electronic]]), and was the first in the world to play [[digital music]].<ref>{{cite web |url=http://www.csiro.au/science/ps4f.html |title=CSIRAC: Australia's first computer |access-date=2007-12-21 |archive-url=https://web.archive.org/web/20071116112251/http://www.csiro.au/science/ps4f.html |archive-date=2007-11-16 |url-status=dead }}</ref><ref name="beebmus">{{cite news|title=Oldest computer music unveiled |url=http://news.bbc.co.uk/1/hi/technology/7458479.stm| date=2008-06-17|access-date=2008-06-18|work=[[BBC News Online]]|last=Fildes|first=Jonathan }}</ref><ref name="Early Computer Music Experiments in Australia, England and the USA">{{cite web|title=MuSA 2017 - Early Computer Music Experiments in Australia, England and the USA |url=https://www.academia.edu/34234640 |work=[[MuSA Conference]] |access-date=18 October 2017 |date=9 July 2017}}</ref><ref name="Doornbusch">{{cite journal|last=Doornbusch|first=Paul|title= Early Computer Music Experiments in Australia and England |journal=[[Organised Sound]]|year=2017|volume=22|issue=2|pages=297–307 [11]|publisher=[[Cambridge University Press]]|doi=10.1017/S1355771817000206|doi-access=free}}</ref><ref name=":0"/><ref name="abc.net.au/radionational/sum-of-all-parts/13.1"/>

After being exhibited at [[Melbourne Museum]] for many years, it was relocated to [[Scienceworks (Melbourne)|Scienceworks]] in 2018 and is now on permanent display in the Think Ahead gallery.<ref name="museumsvictoria.com.au">{{Cite web|url=https://museumsvictoria.com.au/scienceworks/learning/school-programs-and-resources/csirac-the-worlds-oldest-intact-first-generation-electronic-computer/|title=CSIRAC - the world's oldest intact first-generation electronic computer|website=Museums Victoria}}</ref>
A comprehensive source of information about the CSIRA collection, its contributors and related topics is available from [[Museums Victoria]] on their Collections website.<ref name="collections.museumsvictoria.com.au">{{Cite web|url=https://collections.museumsvictoria.com.au/articles/3145|title=CSIRAC Collection|website=Museums Victoria Collections}}</ref>

==History==
The CSIRAC was constructed by a team led by [[Trevor Pearcey]] and Maston Beard, working in large part independently of similar efforts across [[Europe]] and the [[United States]], and ran its first test program (multiplication of numbers) sometime in November 1949.<ref>{{Cite web|url=https://cis.unimelb.edu.au/about/csirac/chron|title=CSIRAC Chronology: CSIRAC, University of Melbourne|website=cis.unimelb.edu.au|others=David Hornsby, Doug McCann, Peter Thorne|date=12 August 2021 |access-date=2023-06-24}}</ref><ref name=":0">{{Cite journal|last=Doornbusch|first=Paul|date=March 2004|title=Computer Sound Synthesis in 1951: The Music of CSIRAC|journal=Computer Music Journal|language=en|volume=28|issue=1|pages=11–12|doi=10.1162/014892604322970616|s2cid=10593824|issn=0148-9267|doi-access=free}}</ref> In restricted operation from late 1950, publicly demonstrated and operational in 1951.<ref>{{Cite journal|date=October 1952|title=9. C.S.I.R.O. Mark I|url=http://www.dtic.mil/docs/citations/AD0694606|journal=Digital Computer Newsletter|language=en|volume=4|issue=4|pages=6}}{{dead link|date=June 2022|bot=medic}}{{cbignore|bot=medic}}</ref>{{sfn|McCann|Thorne|2000|pp=viii, 2-3, 27, 30, 77, 79-80}}<ref>{{cite book|url=https://archive.org/details/bitsavers_onrASurveyomputers1953_8778395|title=A survey of automatic digital computers|last1=Research|first1=United States Office of Naval|date=1953|publisher=Office of Naval Research, Dept. of the Navy|page=[https://archive.org/details/bitsavers_onrASurveyomputers1953_8778395/page/n27 22]|language=en}}</ref>

==Design==
The machine was fairly representative of first-generation [[Vacuum tube|valve]]-driven computer designs. It used [[Mercury (element)|mercury]] [[Delay-line memory|acoustic delay lines]] as its primary data storage, with a typical capacity of 768 20-[[bit]] words, supplemented by a parallel [[Disk storage|disk-type device]] with a total 4096-word capacity and an access time of 10 milliseconds. Its memory clock ran at 1000&nbsp;[[hertz|Hz]], and the [[control unit]], synchronized to the clock, took two cycles to execute an instruction (later the speed was doubled to one cycle per instruction). The [[Computer bus|bus]] (termed the "digit trunk" in their design){{sfn|McCann|Thorne|2000|pp=8–11, 13, 91}} is unusual compared to most computers in that it was [[Serial communication|serial]]—it transferred one bit at a time.

Most of CSIRAC's approximately 2000 valves were of the types [[6SN7]],<ref>6SN7 Double triode, 8-pin, 3.8 W heater</ref> [[6V6]],<ref>{{Cite web |url=http://www.nj7p.org/Tube4.php?tube=6V6 |title=6V6 Beam Power pentode, 8-pin, 2.8 W heater |access-date=2007-01-19 |archive-url=https://web.archive.org/web/20060927064325/http://www.nj7p.org/Tube4.php?tube=6V6 |archive-date=2006-09-27 |url-status=dead }}</ref> EA50 diodes and [[KT66]].<ref>KT66 Beam tetrode, 8-pin, 8.2 W heater</ref> George Semkiw later redesigned the drum-read electronics to use [[germanium]] [[transistor]]s.{{Citation needed|date=May 2025}}

Input to the machine was performed in the form of punched {{convert|3|in|mm|adj=on}} wide, 12-track [[paper tape]],<ref>{{cite web| url = https://www.computerhistory.org/revolution/birth-of-the-computer/4/92/363| title = CSIRAC paper tape (replica)| date = 2010| publisher = [[Computer History Museum]]| access-date = 13 October 2023 }}</ref> after experiments with [[Punched card|punch cards]] proved unsatisfactory.  The machine was controlled through a console which allowed programs to be stepped through one instruction at a time, and featured [[CRT display]]s which showed the contents of registers. Output was through a standard [[teleprinter]] or to punch tape.{{Citation needed|date=May 2025}}

The [[instruction set]] supported the basic set of arithmetic and logical operations, as well as conditional and relative jumps (making it possible to write a library of subroutines). Instructions consisted of three components: a 5-bit "destination" P1-P5, a 5-bit "source" P6-P10, and a 10-bit "address" P11-P20. For instructions that used the main store, the six bits P15-P20 selected one of the 64 logical delay lines. Bits P11-P14 determined the time at which 20 bits of data were written to or extracted from the delay line, and thus represented address of a word within the selected delay line. There were 32 destination gates and 32 source gates; the 10 address bits identified a data word within the store if either the source or destination required access to the store. The total number of source and destination combinations, or different instruction functions, was 1024, although only about 256 of these were used often.<ref>{{cite web|url=http://www.cis.unimelb.edu.au/about/csirac/design.html|title=CSIRAC design|access-date=2018-04-14|archive-date=1 April 2018|archive-url=https://web.archive.org/web/20180401100256/http://www.cis.unimelb.edu.au/about/csirac/design.html|url-status=dead}}</ref> The machine had three 20-bit registers (A, B and C), two of which were involved in multiplication, one 10-bit register which could link to either half of a word, and a group of 16 20-bit registers, addressed via bits P11-P14. In addition the 20-bit program counter (S register), and the instruction register (K) were accessible.{{Citation needed|date=May 2025}}

The machine, like all machines of the era, had no [[operating system]].  A high-level interpreted [[programming language]] called INTERPROGRAM was developed in 1960 by Geoff Hill. It was similar to early forms of [[BASIC programming language|BASIC]], which was designed in 1963 for the 20-bit transistorized [[GE-200 series]].{{Citation needed|date=May 2025}}

In 1950 CSIRAC was used to play music, the first known use of a digital computer for the purpose. The music was never recorded, but it has been accurately reconstructed.<ref name="beebmus"/><ref name=":0"/><ref name="abc.net.au/radionational/sum-of-all-parts/13.1">{{cite web |last1=Werner |first1=Joel |title=13.1 Electronic music's origin story [BONUS] |url=https://www.abc.net.au/radionational/programs/sum-of-all-parts/13.1-electronic-music%E2%80%99s-origin-story/11422534 |website=[[Radio National]] |publisher=[[Australian Broadcasting Corporation]] |access-date=13 May 2021 |language=en |date=16 August 2019}}</ref><ref name="Early Computer Music Experiments in Australia, England and the USA" /><ref name="Doornbusch"/><ref>{{Cite web |last=Doornbusch |first=Paul |date=26 June 2016 |title=How Australia played the world's first music on a computer |url=https://theconversation.com/how-australia-played-the-worlds-first-music-on-a-computer-60381 |website=The Conversation}}</ref>
[[Image:CSIRAC.jpg|right|thumb|CSIRAC, side view]]
In 1955, with the [[Commonwealth Scientific and Industrial Research Organisation|CSIRO]]'s decision that computing research was outside its purview, the machine was transferred from its home at the Radiophysics Laboratory at the CSIRO in Sydney, to the [[University of Melbourne]], where it formed Australia's only academic computing facility until late 1956.  Many pioneers of computer use in Australia{{who|date=August 2014}} had their first exposure to computing there.{{citation needed|date=August 2014}}

==Preservation==
In 1964, CSIRAC was shut down for the last time.  Its historical significance was already recognised at that stage, and it was placed in storage with plans for its later exhibition in a museum.{{Citation needed|date=May 2025}}

The machine was stored in a warehouse through the 1960s and 1970s, before being set up for exhibit at [[Caulfield Institute of Technology]]<ref>{{cite web |title=Slide: CSIRAC Computer, Trevor Pearcey, 1980-1992 |work=Museum Victoria Collections |id=Item MM 68471 |url=http://museumvictoria.com.au/collections/items/761661/slide-csirac-computer-trevor-pearcey-1965-1975 |archive-url=https://archive.today/20120713020456/http://museumvictoria.com.au/collections/items/761661/slide-csirac-computer-trevor-pearcey-1965-1975 |url-status=dead |archive-date=2012-07-13 }}</ref> (later the Caulfield Campus of [[Chisholm Institute of Technology]], and later again the [[Monash University, Caulfield campus|Caulfield Campus of Monash University]]) from 1980 to 1992.  It was then returned to storage.{{Citation needed|date=May 2025}}

Interest in the machine was revived in the 1990s, as it was realised that many of its developers were ageing and history was being lost forever.  A conference about the machine was held in 1996.{{Citation needed|date=May 2025}}

[[File:CSIRAC at Scienceworks, Melbourne.jpg|thumb|CSIRAC display at Scienceworks]]
The machine found a permanent home with [[Museums Victoria]] in 2000. It has not been operable since its shutdown, but many of the programs that ran on it have been preserved, and an [[emulator]] has been written for it. The curators have decided that, aside from the cost of restoring the device, the huge number of repairs that would be required to make it safe to operate (CSIRAC used 30 [[kilowatt]]s of power in operation) would detract from its historical authenticity.{{Citation needed|date=May 2025}}

After being exhibited at [[Melbourne Museum]] for many years, it was relocated to [[Scienceworks (Melbourne)|Scienceworks]] in 2018 and is now on permanent display in the Think Ahead gallery.<ref name="museumsvictoria.com.au"/>

CSIRAC is listed on the [[Victorian Heritage Register]] and is included in a [[Heritage Overlay]].<ref name=VHD>{{Cite web
  | title = CSIRAC (COMMONWEALTH SCIENTIFIC AND INDUSTRIAL RESEARCH ORGANISATION AUTOMATIC COMPUTER)
  | id=H2217
  | work = Victorian Heritage Register
  | publisher = Heritage Victoria
  | url = http://vhd.heritagecouncil.vic.gov.au/places/114928 }}
</ref>

It is listed as a National Engineering Landmark by [[Engineers Australia]] as part of its [[Engineers Australia#Engineering Heritage Recognition Program|Engineering Heritage Recognition Program]].<ref>{{cite web
| url = https://portal.engineersaustralia.org.au/heritage/csirac-computer-1949-64
| title = CSIRAC Computer, 1949-64
| publisher = Engineers Australia
| access-date = 2020-04-27
}}</ref>

== See also ==
* [[Computer music]]
* [[Electronic music]]
* [[History of computing hardware]]
* [[List of vacuum-tube computers]]
* [[SILLIAC]] – Sydney University's second computer

== References ==
;References
{{Reflist}}
* {{cite journal|title=Automatic Computing Machinery: Technical Developments - AN AUTOMATIC COMPUTER IN AUSTRALIA|journal=Mathematics of Computation|date=1952|volume=6|issue=39|pages=167–172|doi=10.1090/S0025-5718-52-99392-7|issn=0025-5718|doi-access=free}}

;Bibliography
{{Refbegin|}}
* {{cite journal|last=Beard|first=M.|author2=Pearcey T.|title=The Genesis of an Early Stored-Program Computer: CSIRAC|journal=IEEE Annals of the History of Computing|volume=6|issue=2|pages=106–115|publisher=IEEE|year=1984|doi=10.1109/MAHC.1984.10014|s2cid=38316671}}
* {{cite book|last=Deane|first=John|title=CSIRAC: Australia's first computer|publisher=Australian Computer Museum Society|year=1997|pages=45p|isbn=0-646-34081-6}}
* {{cite book|last=Doornbusch|first=Paul|title=The Music of CSIRAC, Australia's first computer music|publisher=Common Ground|year=2005|url=http://thehumanities.cgpublisher.com/product/pub.61/prod.10|isbn=1-86335-569-3}}
* {{cite book|last1=McCann|first1=Doug|last2=Thorne|first2=Peter|title=The Last of The First, CSIRAC: Australias First Computer|publisher=University of Melbourne Computing Science|year=2000|url=https://cis.unimelb.edu.au/about/csirac/last-of-the-first|isbn=0-7340-2024-4}} [https://pearcey.org.au/csirac/ Alt URL]  &ndash; A timeline and history of CSIRAC, as well as a collection of presentations from the 1996 conference on the machine.
* {{cite book|last=Pearcey|first=Trevor|title=A History of Australian Computing|publisher=Chisholm Institute of Technology|year=1988|pages=192p|isbn=0-947186-94-8}}
{{Refend}}

== External links ==
* [http://www.cis.unimelb.edu.au/about/csirac/ CSIRAC homepage] &mdash; From the Computation Laboratory at the University of Melbourne's Department of Computing and Information Systems
* [http://www.nationaltreasures.com.au/treasures/computer/ Australian National Treasure — CSIRAC] &mdash; Television segment on CSIRAC
* [https://csiropedia.csiro.au/the-computer-csirac-1965/ The Computer 'CSIRAC'] &mdash; 1965 film
* [http://www.audionautas.com/2011/09/music-of-csirac.html The Music Of CSIRAC] &mdash; Paul Doornbusch's book review (in Spanish) [https://translate.google.com/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.audionautas.com%2F2011%2F09%2Fmusic-of-csirac.html&edit-text= Google translation]
* [http://www.billp.org/CSIRAC CSIRAC Emulator in Java] &mdash; Description of Architecture, Programming details, and a Java Emulator
* {{Cite web|url=http://www.doornbusch.net/CSIRAC/|title=CSIRAC Music|website=www.doornbusch.net|access-date=2018-05-18}} &ndash; Trevor Pearcey interview, MP3s of all of the music played by CSIRAC
*{{cite journal |first=Peter |last=Thorne |title=The CSIR Mark 1/CSIRAC : Australia's First Computer |journal=Resurrection: The Bulletin of the Computer Conservation Society |issue=67 |date=Autumn 2014 |issn=0958-7403 |url=https://www.computerconservationsociety.org/resurrection/res67.htm#d}}
*{{cite journal |first=Barbara |last=Ainsworth  |title=Dr Trevor Pearcey – at the Forefront of Early Computer Design |journal=Resurrection: The Bulletin of the Computer Conservation Society |issue=67 |date=Autumn 2014 |issn=0958-7403 |url=https://www.computerconservationsociety.org/resurrection/res67.htm#e}}
*{{cite web |first1=Roland |last1=Gesthuizen |first2=Gillian |last2=Kidman |first3=Hazel |last3=Tan |first4=Caroline |last4=Pham |title=Open Education Miniconf Keynote: The Who of CSIRAC |date=13 January 2020 |work=[[linux.conf.au|LinuxConfAU]] 2020 |url=https://www.youtube.com/watch?v=301uGGDc7tM |archive-url=https://ghostarchive.org/varchive/youtube/20211212/301uGGDc7tM| archive-date=2021-12-12 |url-status=live}}{{cbignore}}

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{{DEFAULTSORT:Csirac}}
[[Category:1940s computers]]
[[Category:One-of-a-kind computers]]
[[Category:Vacuum tube computers]]
[[Category:Computer-related introductions in 1949]]
[[Category:Science and technology in Australia]]
[[Category:Heritage sites in Melbourne]]
[[Category:Recipients of Engineers Australia engineering heritage markers]]
[[Category:City of Hobsons Bay]]
[[Category:20-bit computers]]
[[Category:Australian inventions]]