Editing SILLIAC (section)

== 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.