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By  Pamela Tyers 16 September 2026 7 min read

Key points

  • CSIRO built Australia's first programmable digital computer, CSIR Mark I, later known as CSIRAC, in 1949.
  • CSIRO researchers also developed Australia’s first computer technologies, networks and required capability.
  • CSIRAC could process calculations around a thousand times faster than anything else in Australia at the time and revolutionised everything from weather forecasting to banking.
It’s the late 1940s: Bing Crosby, The Andrews Sisters and Louis Armstrong are on the radio. Women wear full skirts and gloves inspired by Dior's new fashions and men rarely leave home without a suit and hat.

Digital computers as we now know them aren’t yet invented and in the world of technology, engineering and physics, scientists perform complex calculations by hand or with a mechanical adding machine. Calculating things is very slow – at the rate of about one operation per second. More complex mathematical problems take days or even weeks to complete.

What’s considered the world’s first ‘modern’ computer, ENIAC, was built in the US in 1945 but Australia’s journey into the computer age begins with a vision and a machine unlike anything the country has ever seen.

The birth of Australia’s first computer

The story starts in 1947 with three pioneers: Trevor Pearcey, Maston Beard and Geoff Hill. Working at CSIR’s Radiophysics Laboratory in Sydney, they set out to build Australia’s first computer, or as it was technically known then, a ‘stored-program digital electronic system’. Their vision is a machine capable of performing complex calculations at unprecedented speeds.

The result was CSIR Mark I, later known as CSIRAC (CSIR Automatic Computer). It was Australia's first programmable digital computer and only the fourth stored-program computer in the world.

In order to make it work, the team also had to build Australia’s first computer science and technology capability. The stored program concept, for example, was a crucial breakthrough, and there were no machines with that capability when design work started on the CSIRO Mark 1.

[Title appears: The Computer CSIRAC]

[Camera pans around the computer room to show Dr Frank Hirst and Dr Trevor Pearcey sitting at a computer]

Dr Frank Hirst: Trevor, how did it come that you designed the machine with 16 D Registers? [New text appears: Produced by the CSIRO Film Unit] Dr Trevor Pearcey: Well we first mastered the problems associated with a single register and then realised that we could put in 16 words into one adding unit thereby multiplying the capacity of the adder. [New text appears: Direction, Photography and Editing, Peter Bruce – Sound Recording, David Corke – Production, Stan Evans]

Dr Frank Hirst: Yes, it seems a pity really that more modern machines haven't got quite so many D Registers or index registers as CSIRAC.

Dr Trevor Pearcey: Yes, this is so. Only recently when designers have been aiming at running more than one program at a time have the number of registers increased markedly.

Dr Frank Hirst: This is the computer CSIRAC. It was the first fully automatic electronic digital computer to be built in Australia. [New text appears: Dr. Frank Hirst, University of Melbourne]

It was constructed in the Radiophysics Division of the Commonwealth Scientific and Industrial Research Organisation to the designs of Mr Trevor Pearcey and Mr Maston Beard. Mr Pearcey was responsible for the logical design of the circuitry and Mr Beard engineered the electronic components.

This computer is of advanced electronic design for its day and it has a very flexible command code. We are fortunate to have Mr Pearcey with us now, its designer, and Trevor, perhaps you could relate to us some of the ideas that you had when you designed the machine.

[New text appears: Mr. Trevor Pearcey, CSIRO]

Dr Trevor Pearcey: The automatic digital computer which... CSIRAC was a very early example, was initially the product of the pooling of ideas by the mathematician and the electronic engineer who brought the ideas of the mathematician to physical realisation. Three basic principles are involved in the automatic digital computer. One, that the fast computer must be provided with a sufficient internal store so as to be able to hold its program that is the sequence of operations which it is instructed to perform. The second is that data and program are formally identical and are in fact held within the same store. The third is that program must consist of a network of sequences of instructions and that the computer traverse this network in a manner which is determined by the partial answers. In this way the computer is given the facility for discriminating between differing conditions, the conditions being those which it had already computed and to thereby repeat the program frequently but in slightly different form.

Soon after World War II the need arose in the Division of Radiophysics of what was then CSIR, for both a more rapid computing capability and for continued development of the electronic pulse techniques which had been developed for radar during World War II. Digital computing it was seen would serve both these purposes.

[Image changes to a tracking shot showing racks of electronics and valves within the metal cabinets of CSIRAC, then goes back to Dr Trevor Pearcey]

In 1948 the division undertook the study of automatic digital computing and in 1951 CSIRAC, this machine, was actually exhibited publicly in operating order and has since then been in regular service for the best part of a period of 13 years. During some of this time it has been improved and during the last nine years of its life has been used as a teaching and research machine in the University of Melbourne.

The design, although using engineering methods, which have now been rendered obsolete by the invention of the transistor, concentrated upon logical functions which would render it easy to use and some of them have been incorporated in machines to this day. [Image changes to a zoom into banks of electronic valves within CSIRAC then back to Dr Trevor Pearcey]

A set of 20 binary digits tells the machine how to move one particular datum from one part of the machine to another at the same time carrying out a simple operation upon it such as addition.

The program, which it performs, consists of a set of such simple transfers of data with appropriate transformations during their passage. The main store of CSIRAC and most of the incidental registers consists of a number of acoustic delay lines.

[Image changes to a man removing a long rod from a metal box then changes back to Dr Trevor Pearcey]

These take the form usually of pipes containing mercury, each one about five feet long down which acoustic waves travel taking a time of about one millisecond. When they reach the far end of the pipe they are detected, amplified and recirculated to the starting point. By this means CSIRAC was able to store 756 items of data, that is, six decimal digit items, or the equivalent, and to be able to operate upon them a thousand times a second. This is indeed slow compared with 500,000 operations a second, which are now on current machines.

[Image changes to a pair of hands holding up a wide paper tape with small holes punched through and then a narrower punched paper tape] Its main medium for accepting programs and data is paper tape of two kinds, one a wide kind with 12 channels frequently used for recording programs and one of five channels identical with paper tape used in common telegraphic equipment.

[Image changes to keys on a typewriter then back to Dr Trevor Pearcey]

Program and data are coded automatically by special devices with typewriter type of keyboard and the machine can read these tapes at about 100 rows per second or twenty 5 decimal digit numbers. Output onto similar tape is slower at about six 5 decimal digit numbers over the equivalent and these are printed out after punching at a later stage on similar keyboard instruments.

[Image changes to a large electric motor then back to Dr Trevor Pearcey] CSIRAC has now been rendered obsolete by recent developments in electronics and problems have grown too large to be held within it and too time-consuming to run. Problems are common now which can only be performed on equipment of vastly greater size and speed, computing and storage capacities being at least 500 times that of CSIRAC with correspondingly fast input and output devices. These are all now currently available and are being installed throughout Australia.

Here you see a program being recorded on wide paper tape.

[Image changes to a lady typing on a keyboard then pans over to show holes being punched into a paper tape]

An instruction written by the programmer in a fairly simple computer language on his sheets of paper is transcribed through the keyboard and you will notice that two keys are depressed before a punching action takes place. An instruction then consists of two groups of ten binary digits.

[Image shows the typist picking up the paper ribbon and giving it to Dr Trevor Pearcey who then takes the ribbon and feeds it into another machine]

Thank you. The program has now been put onto paper tape and we will put it onto the reader. For this purpose... for the purpose of this description there is no data on the paper tape. This tape reads the 12 holes row by row and is operated photoelectrically.

[Image changes to Dr Frank Hirst sitting at a console with buttons on it, image then shows paper tape going through the reader then shows a round screen filling up with a grid of dots, image then changes back to Dr Frank Hirst operating the console]

Dr Frank Hirst: We're going to feed the tape now into CSIRAC and I press the appropriate control buttons on the console and the tape is inched forward until we position it into the buffer register at the right spot. Now the bootstrap tape is going in and the tape is moving into the reader. You can actually see it go into the memory filling up the cells of the memory. By switching on the console keyboard we can see the tape in position in store. It's loaded in the memory and we now set the data for the problem and I am setting this on the keyboard registers. This is the number that has to be fed to the program. I fed that number into the machine and now the next number goes in and I start the button here and the calculation takes place and you'll see the results coming out on punched paper tape from the paper tape punch at this stage.

[Image shows paper ribbon with holes punched through coming out of a metal box, then changes to show dots on the round oscilloscope screen]

Now I can see inside the memory tubes and watch the arithmetic registers in action. You can see the counting being done in the D Registers and you can see the accumulator calculating, adding and subtracting and so on. This array of cathode ray oscilloscopes is not evident on more modern machines. Because of the older type of machine these display tubes were present so one could do program testing.

[Image shows Dr Frank Hirst taking the punched paper ribbon out of a metal box and inserting it into the Flexowriter] Now we're putting the results from that calculation into the Flexowriter which is going to print out the results for us and we feed it into the reading device here and we press the start read here and the tape will run into the Flexowriter and the printing of the codes on the tape now takes place.

This is a loan repayment schedule. The loan is being amortised over several years. This is the principal outstanding at the beginning of the first quarter. This column shows the interest at 6% payable for the quarter and this is the amount being paid off the loan. As the loan schedule goes of course the interest becomes less each quarter and the repayment is greater. And this is then done by the machine in a few minutes but on a desk machine of course it would take quite a long time. The program stays in the machine and a different loan can be calculated by just pressing the next parameters in for the loan amount.

[Image shows close up of numbers being printed on a piece of paper]

Now we're coming to the final payment and the machine will add up the complete total of all the interest paid in the first column and the complete amount of money paid off the loan and this of course balances with the outstanding amount of the first quarter.

[Image changes to Dr Trevor Pearcey sitting at the control console]

Dr Trevor Pearcey: I have said that CSIRAC was easy to use. Let me illustrate by mentioning a few points of its design. From the operator's point of view the display of the operations was comprehensive and convenient.

[Image changes to show display tubes with dots appearing and disappearing then pans to show a panel with small blinking light bulbs]

The state of the store and the arithmetical registers was shown as arrays of spots or traces on small cathode ray tubes and the state of the control system was made visible as rows of lights on the panels in front of the control console. A switchboard provided facilities for manual control of a program and for insertion of requisite data while the program was running other than the data, which was provided on the punched paper tapes.

[Image changes to show Dr Frank Hirst sitting at a desk with an open book]

Dr Frank Hirst: Well that is the story of CSIRAC. This machine, which is still in operation, is perhaps the oldest at present in the world and it is fitting that this machine is to be stored in the Applied Science section of the National Museum. It will be a historic exhibit and lots of people in the future should gain much information about early days in computing from the presence of CSIRAC in the museum. We are very pleased that it's going there because this machine has been used for hundreds of computations in research projects and been used to teach many students in the University of Melbourne.

[New text appears: END]


When computing filled a double garage

One of CSIRAC’s creators Trevor Pearcey, surveying the CSIRAC machine (1952).

By modern standards, CSIRAC was enormous. It was roughly the size of a double garage and contained thousands of electronic components, like vacuum tubes and mercury delay lines used for memory storage. It used the electricity of a suburban street, yet it had only a fraction of the brainpower of even the simplest modern smartphone.

But in its time, CSIRAC was a technological marvel. It could process calculations around a thousand times faster than anything else in Australia at the time and revolutionised everything from weather forecasting to banking. It even played what is thought to be the first ever computer-generated music, Colonel Bogey, to the audience at Australia’s first computer conference in June 1951.

CSIRAC ran its first successful test program in November 1949 and quickly became one of Australia's most important scientific tools, supporting research across a wide range of disciplines.

Improvements were steadily made to the computer in the early 1950’s and it provided a computing service to all of CSIRO from 1951 to 1955.

In 1956 CSIRAC was dismantled, loaded onto trucks and driven down the Hume Highway to the University of Melbourne, where it was used until 1964. Over its 14-year lifetime, CSIRAC processed more than 1000 projects. It is now on display at Melbourne Museum and is the world’s oldest surviving stored program electronic computer.

Trevor Pearcey's vision

While Pearcey helped create Australia's first computer, he was also thinking about the future of computing. In 1948, before CSIRAC had even become fully operational, he published an article titled Modern Trends in Machine Computation. In it, he suggested that information might one day be accessed remotely through telephone and teleprinter networks.

He wrote that an ‘automatic encyclopaedia service’ could one day operate through national communications systems. Decades before the development of the internet and online search engines, Pearcey had anticipated a world where information could be retrieved electronically from distant computers.

Creating a national computing service

By the late 1950s, computing had become increasingly important to scientific research but CSIRO researchers, spread across Australia, generally had little or no access to advanced computing facilities.

In 1958, Trevor Pearcey met with Edmund ’Alf’ Cornish, head of CSIRO's Division of Mathematical Statistics. Cornish proposed the creation of a central computing laboratory to serve the organisation's growing needs. Together with CSIRO mathematician and programmer Geoff Hill, they proposed locating a powerful central computer in Canberra, supported by smaller regional computers in Sydney, Melbourne and Adelaide. The machines would be compatible with one another, allowing scientific work to be distributed across the network regardless of where researchers were located.

In the early 1960s, the CSIRO Executive and Federal Cabinet approved a grant of 3 million pounds (around $115 million today) to establish the network for CSIRO and government departments with scientific computing needs. Four years later, CSIRO installed a large central machine in a new building in Canberra, with compatible satellite systems in Sydney, Melbourne and Adelaide. The machines all ran the same computer language, Fortran, which despite its age, is still important to high-performance computing.

A network before networks

Initially, this was not an electronic ‘network’. Scientists prepared their programs on punch cards and sent them by plane to Canberra. The jobs were typically processed overnight and results were returned the next morning.

Although slow by today's standards, this arrangement effectively created a nationwide computing service. Researchers from across Australia could access advanced computing resources that would otherwise have been unavailable to them. It was a network that was ‘waiting to happen’.

Many of the technologies needed to support the system did not yet exist commercially so CSIRO staff developed them themselves. Brian Austin built the operating system, called DAD (for ‘drums and displays’), which was later exported to the US. Henry Hudson developed software tools including editors and networking utilities, while other researchers created programs for job scheduling, data storage and interactive computing. These innovations were developed largely in-house and were critical to the success of the network.

The birth of CSIRONET

By the late 1960s, CSIRO researchers began experimenting with remote computer access. Brian Austin and colleagues connected Teletype machines to the Canberra machine, first locally and then over greater distances. One experiment linked a remote site a kilometre away using a cable running along the boundary of the National Botanic Gardens. Despite suffering a major setback when lightning struck the cable and damaged equipment, the experiment proved that remote computer access was possible.

In 1969, CSIRO moved from experimentation to implementation. It leased telecommunications lines and connected computing facilities across Australia, creating one of the country's first wide-area computer networks. Programmer John Paine developed Nodecode, software that packaged data for transmission between computers. This represented an early form of packet switching, a key technology which the internet was later based on.

The new network became known as CSIRONET. Throughout the 1970s it expanded quickly, connecting scientists across the nation. Researchers could submit jobs electronically, access central computing resources and collaborate more effectively. Dial-up connections even meant staff could work remotely from home years before personal computers became commonplace.

By 1976 most CSIRO divisions around Australia were connected. Over the following decades the network expanded to support email, advanced data storage systems, multiple mainframe computers and Australia's first true supercomputer. At its peak, CSIRONET served thousands of users across research and government organisations.

Then of course, another big breakthrough in the 1990s – CSIRO invented wireless local area network technology, which lead to modern WiFi.

A lasting legacy

The technologies developed by CSIRO helped establish Australia's early computing infrastructure and capability, and influenced the way scientific research was conducted across the country. Some of the research also contributed to the concepts and functions of modern-day computers globally.

From CSIRAC to CSIRONET to WiFi, CSIRO has shown how computing could connect people, accelerate discovery and solve complex problems. In CSIRO’s centenary year, the national science agency is still at the forefront of developing computing power that helps Australia punch above its weight in scientific achievement.

Its High Performance Computing Facility supports major national research collaborations across climate science, genomics, energy, materials, space, advanced manufacturing and more, while meeting the growing demand in data-intensive and AI-driven science. The Vetra AI infrastructure, for example, is a cutting-edge computing resource for faster, safer data processing in robotics and other AI-powered technologies.

The vision of Trevor Pearcey and his colleagues continues to live on in the digital systems, networks and online services that Australians rely on every day. Long before the internet became a reality, CSIRO's computing pioneers were already laying the foundations for Australia's connected future.
Read more about CSIRO's computing history