CSIRAC originally known as CSIR Mk 1, was Australia

Australia

Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

's first digital computer, and the fourth stored program computer in the world. It was first to play digital music and is one of only a few surviving first-generation computers (others include the Zuse Z4 and at least two Ferranti Pegasus computers).

The CSIRAC was constructed by a team led by Trevor Pearcey

Trevor Pearcey

Trevor Pearcey was a British-born Australian scientist, who created CSIRAC, one of the first ever stored-program electronic computers in the world....

 and Maston Beard, working in large part independently of similar efforts across Europe

Europe

Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...

 and the United States

United States

The United States of America is a federal constitutional republic comprising fifty states and a federal district...

, and ran its first test program sometime in November 1949.

The machine was fairly representative of first-generation valve

Vacuum tube

In electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...

-driven computer designs. It used mercury

Mercury (element)

Mercury is a chemical element with the symbol Hg and atomic number 80. It is also known as quicksilver or hydrargyrum...

 acoustic delay lines

Delay line memory

Delay line memory was a form of computer memory used on some of the earliest digital computers. Like many modern forms of electronic computer memory, delay line memory was a refreshable memory, but as opposed to modern random-access memory, delay line memory was serial-access...

 as its primary data storage, with a typical capacity of 768 20-bit

Bit

A bit is the basic unit of information in computing and telecommunications; it is the amount of information stored by a digital device or other physical system that exists in one of two possible distinct states...

 words (later doubled), supplemented by a parallel disk-type device

Disk storage

Disk storage or disc storage is a general category of storage mechanisms, in which data are digitally recorded by various electronic, magnetic, optical, or mechanical methods on a surface layer deposited of one or more planar, round and rotating disks...

 with a total 1024-word capacity and an access time of 10 milliseconds. Its memory clock ran at 1000 Hz

Hertz

The hertz is the SI unit of frequency defined as the number of cycles per second of a periodic phenomenon. One of its most common uses is the description of the sine wave, particularly those used in radio and audio applications....

, and the control unit

Control unit

A control unit in general is a central part of the machinery that controls its operation, provided that a piece of machinery is complex and organized enough to contain any such unit. One domain in which the term is specifically used is the area of computer design...

, synchronized to the clock, took two cycles to execute an instruction (later the speed was doubled to one cycle per instruction). The bus

Computer bus

In computer architecture, a bus is a subsystem that transfers data between components inside a computer, or between computers.Early computer buses were literally parallel electrical wires with multiple connections, but the term is now used for any physical arrangement that provides the same...

 (termed the "digit trunk" in their design) is unusual compared to most computers in that it was serial

Serial communication

In telecommunication and computer science, serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent as a whole, on a link with several parallel channels...

—it transferred one bit at a time. The instruction set

Instruction set

An instruction set, or instruction set architecture , is the part of the computer architecture related to programming, including the native data types, instructions, registers, addressing modes, memory architecture, interrupt and exception handling, and external I/O...

 was minimal, but 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).

Input to the machine was performed in the form of punched paper tape, after experiments with punch cards

Punched card

A punched card, punch card, IBM card, or Hollerith card is a piece of stiff paper that contains digital information represented by the presence or absence of holes in predefined positions...

 proved unsatisfactory. The machine was controlled through a console which allowed programs to be stepped through one at a time, and featured CRT

Cathode ray tube

The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...

 displays which showed the contents of registers. Output was through a standard teleprinter

Teleprinter

A teleprinter is a electromechanical typewriter that can be used to communicate typed messages from point to point and point to multipoint over a variety of communication channels that range from a simple electrical connection, such as a pair of wires, to the use of radio and microwave as the...

 or to punch tape.

The machine, like all machines of the era, had no operating system

Operating system

An operating system is a set of programs that manage computer hardware resources and provide common services for application software. The operating system is the most important type of system software in a computer system...

. A high-level interpreted programming language

Programming language

A programming language is an artificial language designed to communicate instructions to a machine, particularly a computer. Programming languages can be used to create programs that control the behavior of a machine and/or to express algorithms precisely....

 called INTERPROGRAM was developed in 1960 by Geoff Hill. It was similar to early forms of BASIC, which was designed in 1963 for the 20-bit transistorized GE-200 series

GE-200 series

The GE-200 series was a family of small mainframe computers of the 1960s, built by General Electric.The main machine in the line was the GE-225. It used a 20-bit word, of which 13 bits could be used for an address. Along with the basic CPU the system could also include a floating-point unit, or...

.

In 1950 or 1951, 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.

In 1955, with the CSIRO

Commonwealth Scientific and Industrial Research Organisation

The Commonwealth Scientific and Industrial Research Organisation is the national government body for scientific research in Australia...

'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

University of Melbourne

The University of Melbourne is a public university located in Melbourne, Victoria. Founded in 1853, it is the second oldest university in Australia and the oldest in Victoria...

, where it formed Australia's only academic computing facility until late 1956. Many pioneers of computer use in Australia had their first exposure to computing there.

Most of CSIRAC's approximately 2000 valves were of the types 6SN7

6SN7

6SN7 is a dual triode vacuum tube, on an 8 pin octal base. Although the 6S—series tubes are often metal cased, the 6SN7 is generally found only in a glass GT size envelope. The 6SN7 is basically two 6J5 triodes in one glass envelope.-History:...

, 6V6

6V6

The 6V6 is a beam-power tetrode, introduced by Radio Corporation of America RCA United States in late 1937, and still in use in niche applications.Similar to its predecessor the 6L6, the 6V6 was far more widely used...

, EA50 Diodes and KT66

KT66

The KT66 is a beam tetrode/kinkless tetrode vacuum tube for audio amplification.KT66 is the designator for a vacuum tube introduced by Marconi-Osram Valve Co. Ltd. of Britain in 1937....

. George Semkiw later redesigned the drum read electronics to use germanium

Germanium

Germanium is a chemical element with the symbol Ge and atomic number 32. It is a lustrous, hard, grayish-white metalloid in the carbon group, chemically similar to its group neighbors tin and silicon. The isolated element is a semiconductor, with an appearance most similar to elemental silicon....

 transistor

Transistor

A transistor is a semiconductor device used to amplify and switch electronic signals and power. It is composed of a semiconductor material with at least three terminals for connection to an external circuit. A voltage or current applied to one pair of the transistor's terminals changes the current...

s.

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.

The machine was stored in a warehouse through the 1960s and 1970s, before being set up for exhibit at Caulfield Institute of Technology from 1980 to 1992. It was then returned to storage.

Interest in the machine was revived in the 1990s, as it was realised that many of its developers were aging and precious history was being lost forever. A conference about the machine was held in 1996.

The machine finally found a permanent home in the Melbourne Museum

Melbourne Museum

Melbourne Museum is located in the Carlton Gardens in Melbourne, Australia, adjacent the Royal Exhibition Building.It is the largest museum in the Southern Hemisphere, and is a venue of Museum Victoria, which also operates the Immigration Museum and Scienceworks Museum.The museum has seven main...

 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

Emulator

In computing, an emulator is hardware or software or both that duplicates the functions of a first computer system in a different second computer system, so that the behavior of the second system closely resembles the behavior of the first system...

 has been written for it. The curators have decided that, aside from the cost of restoring the device, that the huge number of repairs that would be required to make it safe to operate (CSIRAC used 30 kilowatts of power in operation) would detract from its historical authenticity.

CSIRAC is listed on the Victorian Heritage Register

Victorian Heritage Register

The Victorian Heritage Register lists places of cultural heritage significance to the State of Victoria, Australia. It has statutory weight under the Heritage Act 1995 which establishes Heritage Victoria as the permit authority...

 and is included a Heritage Overlay

Heritage Overlay

A Heritage Overlay or HO is one of a number of planning scheme overlays contained in the Victorian Planning Provisions, for use in planning schemes in Victoria, Australia...

.

See also

• Electronic music
  Electronic music
  Electronic music is music that employs electronic musical instruments and electronic music technology in its production. In general a distinction can be made between sound produced using electromechanical means and that produced using electronic technology. Examples of electromechanical sound...
  
  
• Computer music
  Computer music
  Computer music is a term that was originally used within academia to describe a field of study relating to the applications of computing technology in music composition; particularly that stemming from the Western art music tradition...
  
  
• SILLIAC
  SILLIAC
  The SILLIAC , an early computer built by the University of Sydney, Australia, was based on the ILLIAC and ORDVAC computers developed at the University of Illinois, which in turn were based on the IAS architecture developed by John von Neumann.SILLIAC had its genesis in...
  
  Sydney University's first computer

External links

• CSIRAC homepage – From the Computation Laboratory at the University of Melbourne's Dept of Computer Science and Software Engineering
• Australian National Treasure - CSIRAC – Television segment on CSIRAC
• The Computer 'CSIRAC' – 1965 film
• The Music Of CSIRAC – Paul Doornbusch's book review