Editing SILLIAC

{{Use dmy dates|date=April 2022}}
[[File:SILLIAC logo.png|right|300px]]
[[File:SILLIAC being services.jpg|right|thumb|SILLIAC being serviced by Peter Aplin of Sydney University]]

The '''SILLIAC''' ('''''S'''ydney version of the [[ILLIAC I|'''Ill'''inois '''A'''utomatic '''C'''omputer]]'', i.e. the '''''S'''ydney '''ILLIAC'''''), an early [[computer]] built by the [[University of Sydney]], [[Australia]], was based on the ILLIAC and [[ORDVAC]] computers developed at the [[University of Illinois at Urbana–Champaign|University of Illinois]].

Like other early computers, SILLIAC was physically large. The computer itself was a single large cabinet 2.5&nbsp;m high, 3&nbsp;m wide and 0.6&nbsp;m deep in one room. Its power supply occupied a second room and [[air conditioning]] required an additional room in the basement.

It ran until May 17, 1968, when it was replaced by a faster and bigger machine. Although it was then broken up, some pieces of SILLIAC are at the Powerhouse Museum and others are displayed at Sydney University.

==History==
SILLIAC<ref>{{cite book|last = Deane|first = John|title = SILLIAC &ndash; Vacuum Tube Supercomputer|location = Sydney|publisher = Science Foundation for Physics within [[the University of Sydney]], in association with the [[Australian Computer Museum Society]]|year = 2006|isbn = 9781864878448}}</ref> had its genesis in late 1953 when [[Harry Messel]], the dynamic new head of the [[University of Sydney School of Physics|School of Physics]], and [[John Blatt]], newly arrived researcher, both independently realised that the school needed an electronic computer as a tool for [[theoretical physics]].  Whilst the first computer in the southern hemisphere, the [[CSIR Mk 1]], was already running elsewhere on the University of Sydney grounds, there were several serious impediments to its use by the School of Physics:  The CSIR Mk 1 was fully occupied with [[Commonwealth Scientific and Industrial Research Organisation|CSIR]] research and John Blatt found its staff very unhelpful; and, as a [[serial architecture]] computer, it was far too slow for the sort of problems that Blatt and Messel envisaged.  The solution was for the School to build its own computer.

Rather than design a computer from scratch, Blatt and Messel chose to copy the design of the [[ILLIAC]] for which the University of Illinois were happy to provide plans and assistance. [[John Algie]], then maintenance engineer for [[CSIRAC]], estimated the cost at [[Australian pound|AU£]]35,200, which was approximately ten times the cost of a Sydney suburban house at the time.<ref name = SAM_Timelines2021>{{cite magazine|title = The Machine that Advanced Australia into the Computer Age: SILLIAC|last = Dodd|first = George|date = 5 May 2021|magazine = [[Sydney Alumni Magazine]]|publisher=[[The University of Sydney]]|issue = 13|pages = 24–25|url = https://www.sydney.edu.au/news-opinion/news/2021/05/05/silliac-the-machine-that-brought-australia-into-the-computer-age.html|access-date = 11 June 2021}}</ref>  Based on this, a decision to proceed was made at the end of 1953. A mutual friend introduced Messel to [[Adolph Basser]],<ref>{{cite book|last1=Rutledge |first1=Martha |last2=Lemon |first2=Andrew| chapter=Basser, Sir Adolph (1887–1964) |chapter-url=http://adb.anu.edu.au/biography/basser-sir-adolph-9447 |title=[[Australian Dictionary of Biography]] |volume=13 |year=1993 |publisher=[[Melbourne University Press]] |access-date=18 October 2018}}</ref> who donated AU£50,000 towards the computer.<ref name=ji>{{cite news |last=Ji |first=Julie |title=Celebrating 50 years of computers at Sydney |url=http://sydney.edu.au/news/84.html?newsstoryid=1254 |url-status=dead |archive-url=https://web.archive.org/web/20071030042301/http://sydney.edu.au/news/84.html?newsstoryid=1254|archive-date = 30 October 2007|access-date=18 October 2018 |publisher=[[The University of Sydney]] |website=University of Sydney News|date=5 September 2006}}</ref><ref name=jacobs>{{cite magazine |last=Jacobs |first=Marie |title=Love at First Byte |magazine=[[Sydney Alumni Magazine]]|date=Winter 2006 |pages=12–15 |url=http://www.alumni.sydney.edu.au/s/965/images/editor_documents/alumni-magazine/06-winter/2006-winter-sam.pdf |publisher=[[The University of Sydney]] |access-date=18 October 2018}}</ref>  SILLIAC's eventual cost was AU£75,000.<ref name=SAM_Timelines2021 />

In July 1954, [[Standard Telephones and Cables]] was contracted to build the computer, with testing and installation performed by technicians within the School of Physics.

SILLIAC's first scientific computation was carried out by PhD student Bob May (later [[Robert May, Baron May of Oxford]]) in June 1956,<ref name = SAM_Timelines2021 /> after self tests had been completed successfully. Another PhD student user in that month was [[John C. Butcher]] (later Professor of Mathematics at the [[University of Auckland]]),.<ref name = Butcher1958>{{cite journal |last1=Butcher |first1=John C. |last2=Chartres |first2=B. A. |last3=Messel |first3=H. |title=Tables of average numbers for electron-photon showers at small depths of absorber |journal=Nuclear Physics |date=1958 |volume=6 |pages=271–281 |doi=10.1016/0029-5582(58)90106-8}}</ref> Users were provided with regular access from July 9, with the official opening conducted on September 12.

Having abandoned its own computer system in 1955, [[CSIRO]] Division of Radiophysics in 1957 rented computing time on SILLIAC at a half-price rate of {{AUD|16000|year=1957}} for 400 hours to perform analysis on data received by its equipment at Murrybank Field.{{sfn|Wendt|Orchiston|Slee|2011|p=450}}

[[Barry de Ferranti]], a pioneer involved in the construction of SILLIAC described the main cabinet of the computer as about 2 metres high, 1 metre deep and 5 metres long with glass panels at the front and light switches that indicated what was going on inside.

It ran until May 17, 1968, when it was replaced by a faster and bigger machine. SILLIAC has now been broken up into pieces with parts of it placed on display in the [[Chau Chak Wing Museum]],<ref name = SAM_Timelines2021 /> which opened in November 2020.<ref>{{cite news|title = Sydney's newest museum opens|date = 16 November 2020|access-date = 11 June 2021|website = University of Sydney News|publisher = [[The University of Sydney]]|url = https://www.sydney.edu.au/news-opinion/news/2020/11/16/sydney-s-newest-museum-opens.html}}</ref>

== Hardware specifications ==
* Parallel, asynchronous operation.  Approximately 13,000 adds, 1400 multiplies or 1200 divides per second
* [[Computer memory|Memory]]: 1024 [[Word (data type)|words]] of 40 [[bit]]s using 40 [[Williams tube]]s
* Two 20-bit instructions per word.
* Approximately 150 operations on two [[Processor register|registers]]
* [[Punched tape|Paper tape]] input at 200 characters per second (cps),<ref>'The Electronic Computer "SILLIAC" ', The Nuclear Research Foundation, Sydney, September 1956.</ref> paper tape output at about 50 cps or teleprinter output at 10 cps.  Four [[Magnetic tape data storage|magnetic tape]] units added in 1958
* Initially 2768 valves. Increased to 2911 during 1958 upgrade
* Power consumption: 35&nbsp;[[Watt|kW]]
* Average of 11 hours between failures

Like most of the IAS family, SILLIAC was not an exact copy of ILLIAC. One important change was the use of [[2C51]]<ref>[http://www.nj7p.org/Tube4.php?tube=2C51 2C51 Medium-Mu Twin Triode] {{webarchive|url=https://web.archive.org/web/20070928065352/http://www.nj7p.org/Tube4.php?tube=2C51 |date=2007-09-28 }}, 9 pins, 2.2W heater</ref> [[Vacuum tube|valves]] in place of the more common [[6J6]].<ref>[http://www.nj7p.org/Tube4.php?tube=6J6 6J6 Medium-Mu Twin Triode] {{webarchive|url=https://web.archive.org/web/20060927111839/http://www.nj7p.org/Tube4.php?tube=6J6 |date=2006-09-27 }}, 7 pins, 2.8W heater</ref> The 2C51 had been developed by [[Bell Labs]] for use in undersea telephone repeaters and had about 5 times the life (for 6 times the cost).  This decision significantly improved the [[Reliability engineering|reliability]] of SILLIAC compared to its contemporaries.

== Conservation ==
Some pieces of SILLIAC are at the [[Powerhouse Museum]] and others are displayed at Sydney University.<ref>[http://www.theage.com.au/news/technology/the-computer-that-launched-a-revolution/2006/09/11/1157826868138.html The Age - Computer that launched a revolution] - Louisa Hearn - 12 September 2006</ref>
When it had been broken up, parts had originally been given to a range of people, including 14 schoolchildren who had requested the University for mementoes.{{sfn|Deane|2010|p=6}}

In March 2008, the Australian Computer Museum Society was seeking alternative storage, or risked its collection, including important components of SILLIAC, being scrapped.<ref>[https://archive.today/20120721121022/http://www.abc.net.au/news/stories/2008/03/14/2189966.htm Heritage computers facing scrap heap], [[ABC Online]], 14 March 2008, accessed 15 March 2008</ref>

In 2023 the Australian Computer Museum Society now has a venue for displaying the parts of SILLIAC that are in its collection.

==See also==
* [[CSIR Mk 1]], Sydney University's first computer
* [[List of vacuum-tube computers]]

== References ==
{{Reflist}}

== Sources ==
{{refbegin}}
* {{cite conference|book-title=Highlighting the History of Astronomy in the Asia-Pacific Region: Proceedings of the ICOA-6 Conference|editor1-first=Wayne|editor1-last=Orchiston|editor2-first=Tsuko|editor2-last=Nakamura|editor3-first=Richard G.|editor3-last=Strom|publisher=Springer Science & Business Media|year=2011|isbn=9781441981615|title=The Contribution of the Division of Radiophysics Murraybank Field to International Radio Astronomy|author1-first=Harry|author1-last=Wendt|author2-first=Wayne|author2-last=Orchiston|author3-first=Bruce|author3-last=Slee}}
* {{cite conference|book-title=History of Computing: Learning from the Past: IFIP WG 9.7 International Conference, HC 2010, Held as Part of WCC 2010, Brisbane, Australia, September 20&ndash;23, 2010, Proceedings|editor1-first=Arthur|editor1-last=Tatnall|publisher=Springer|year=2010|isbn=9783642151996|title=Connections in the history of Australian computing|author1-first=John|author1-last=Deane}}
{{refend}}

== External links ==
* [http://www.abc.net.au/rn/scienceshow/stories/2007/1810643.htm#transcript The Science Show about SILLIAC]
* [https://www.uraone.com/computers/Silliac/ David Green's SILLIAC page] - Programming Manuals and an emulator
* [http://www.powerhousemuseum.com/collection/database/index.php?irn=151086 Description and Image of a Component] in the collection of the [[Powerhouse Museum]]

{{University of Sydney}}

{{DEFAULTSORT:Silliac}}
[[Category:IAS architecture computers]]
[[Category:Vacuum tube computers]]
[[Category:University of Sydney]]