What was the CSIR Mark One computer?

The CSIR Mark One, later renamed CSIRAC, was one of the world's first electronic stored-program computers. Designed in Sydney by Trevor Pearcey and Maston Beard using war-surplus radar parts, it ran its first program in November 1949. It is the only fully intact first-generation computer surviving on Earth today, preserved at Museums Victoria.

What was the first computer to play digital music?

The CSIR Mark One performed the earliest known digital computer music in Sydney in June 1951, playing Colonel Bogey March and The Bonnie Banks o' Loch Lomond. Mathematician Geoff Hill programmed the tunes using a speaker attached to the pulse bus. However, Manchester's Ferranti computer produced the oldest surviving physical audio recording later that same year.

Why was the CSIR Mark One moved from Sydney to Melbourne?

The CSIRO decommissioned the computer in 1955 because laboratory chief Edward George Bowen chose to focus resources on radio astronomy and cloud seeding rather than hardware. The machine was dismantled into ten cabinets, driven 900 kilometres down the Hume Highway, and recommissioned at the University of Melbourne in June 1956 under Frank Hirst.

How was the Australian SILLIAC computer funded and used?

Physicist Harry Messel secured funding for SILLIAC from jewellery magnate Sir Adolf Basser, who donated 50,000 Australian pounds after his racehorse Delta won the Melbourne Cup. Built by Standard Telephones and Cables and launched in June 1956, SILLIAC calculated the structural matrices for the Sydney Opera House roof and processed cosmic ray data.

The Glass and Mercury Brain of Sydney

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The Sydney Wire Room

CSIR Mark One runs its first program, November 1949

~2,000 valves, 30 kilowatts, mercury delay-line memory

Built by Trevor Pearcey and Maston Beard from radar surplus

Ada: It's late nineteen forty-nine, in a lab in Sydney, and a room is humming with roughly two thousand glowing valves and the warmth of thirty kilowatts, enough to light a whole suburban street. The thing drawing all that power is one of the first electronic computers on Earth.⁶⁷

Theo: And I'm guessing nobody in Sydney expected Australia to be anywhere near the front of that race.

Ada: Nobody. I'm Ada, that's Theo, and this is Historai, where today we follow a machine built from war-surplus radar parts that learned to sing, then survived when every rival was scrapped.

Theo: So who actually built it?

Ada: A British radar physicist named Trevor Pearcey, who'd worked alongside Douglas Hartree in the war, teamed with an engineer called Maston Beard. They designed the CSIR Mark One from scratch, and in November nineteen forty-nine it ran its first successful program.⁶⁷

Theo: Built from scratch, from spare parts, at the bottom of the world.

Ada: Twenty-bit words, serial architecture, and memory stored as pulses bouncing through tubes of liquid mercury. Then a mathematician, Geoff Hill, wired a raw speaker straight onto the machine's pulse bus, so he could hear the errors in the rhythm.¹⁴

Colonel Bogey in Binary

June 1951: earliest known digital computer music performed

Ran ~1,000 operations per second

Computed Snowy Mountains dam and skyscraper loads

Theo: Hang on, he was listening to the computer think? What did it sound like?

Ada: Clicks and buzzes, each loop its own tempo. But Hill realized that if he timed those loops carefully, he could pick the pitch of the pulses, and that means notes.⁴

Theo: So he turned a debugging trick into an instrument.

Ada: Exactly. In June nineteen fifty-one, at Australia's very first computer conference, the CSIR Mark One played Colonel Bogey March and The Bonnie Banks o' Loch Lomond. It's the earliest known digital computer music anywhere, played before Manchester's Ferranti machine.⁴⁷

Theo: Before Manchester? I always heard Manchester got there first.

Ada: This is where we have to be careful. Sydney performed it in mid nineteen fifty-one, but nobody recorded it at the time. Manchester's Ferranti left the oldest surviving physical audio recording, later that same year. So first performance, Sydney; oldest tape, Manchester.⁴

Theo: Fair enough. And was it just a party trick, or did the thing earn its keep?

Ada: Oh, it worked for its living. It ran one thousand operations a second, about a thousand times faster than a human on a mechanical calculator. It computed flood flows and rock stresses for the Snowy Mountains Hydroelectric Scheme and wind loads for Australia's first skyscrapers.⁶⁷

Theo: That's a serious workload for a machine made of radar scraps.

Ada: And by some counts it was the fourth or fifth stored-program computer in the world, depending on whether you count the short-lived American BINAC as fully operational. Either way, Sydney was at the cutting edge. And then the people in charge decided electronic computing hardware was a distraction from radio astronomy.³⁷

Convoy on the Hume Highway

Decommissioned in Sydney, 1955, split into ten cabinets

Trucked 900 km down the Hume Highway to Melbourne

Recommissioned 14 June 1956 as CSIRAC

Theo: Wait, they built one of the world's first computers and then just... let it go?

Ada: The lab's chief, Edward George Bowen, wanted to pour resources into radio astronomy, the dish that became Parkes, plus cloud-seeding work. And the bureaucracy ruled that the CSIRO would get out of hardware altogether.⁷

Theo: So what happens to a thirty-kilowatt machine when the owner wants it gone?

Ada: They decommissioned it in Sydney in nineteen fifty-five and took it apart into ten massive cabinets. Those cabinets were loaded onto semi-trailers and driven nine hundred kilometres down the Hume Highway to the University of Melbourne.³⁷

Theo: Down the Hume on nineteen-fifties roads? That machine's memory was literally tubes of mercury and delicate timing.

Ada: Bumpy the whole way. But it got there, and on the fourteenth of June nineteen fifty-six it was recommissioned under Frank Hirst, and renamed CSIRAC, the CSIR Automatic Computer.¹³

Theo: A second life, basically.

Ada: And a busy one. In Melbourne it handled more than seven hundred scientific and industrial projects right through to nineteen sixty-four. Sydney had thrown away its lead, but the machine itself just kept working.¹³

Messel, Horses, and SILLIAC

Harry Messel funds SILLIAC with £50,000 from Sir Adolf Basser

Money traced to racehorse Delta's Melbourne Cup win

SILLIAC computed Sydney Opera House roof matrices

Theo: So with the CSIR machine heading to Melbourne, what did Sydney's scientists do for computing?

Ada: Enter Harry Messel, a flamboyant Canadian physicist at the University of Sydney. He found the old Mark One too slow and permanently booked out, so he decided to build his own.⁵

Theo: And where does a university physicist find that kind of money in the nineteen fifties?

Ada: This is my favourite part. He got fifty thousand Australian pounds, millions in today's money, from a jewellery magnate and philanthropist, Sir Adolf Basser.⁵

Theo: Just handed over fifty thousand pounds?

Ada: The money followed a win at the Melbourne Cup. Basser's thoroughbred, named Delta, took the race, and some of those winnings bankrolled a computer.⁵

Theo: So Australia's second great machine was funded, essentially, by a racehorse.

Ada: Essentially, yes. Standard Telephones and Cables built it as a clone of the American ILLIAC design from Illinois. They called it SILLIAC, and it went live in June nineteen fifty-six, the same month CSIRAC fired up in Melbourne.⁵

Theo: What made SILLIAC better than the mercury-tube original?

Ada: Twenty-eight hundred valves recycled from Bell Labs undersea cables, remarkably reliable, around eleven hours between failures, with forty Williams cathode-ray tubes for memory instead of mercury.⁵

Theo: And it earned its keep too?

Ada: It calculated the structural matrices for the Sydney Opera House roof and crunched high-energy cosmic ray data. Meanwhile Trevor Pearcey was looking at this whole landscape and seeing a problem nobody else had.⁵

Theo: Which was?

Ada: That a lone mainframe, however fast, was nearly useless on a continent this size, with cities thousands of kilometres apart. The future wasn't one big brain. It was connecting them.

Lines Across the Continent

Pearcey designs CSIRONET packet-switching network, 1963

Linked CSIRO mainframes across remote state capitals

1982: Australian-designed Microbee fills school labs

Ada: So Pearcey shifted his whole focus to networks. In nineteen sixty-three he designed CSIRONET, one of the world's earliest working wide-area packet-switching networks.⁸

Theo: Packet-switching in nineteen sixty-three? That's the core idea behind the internet, and this is years before the commercial networks.

Ada: Years before. It linked CSIRO mainframes and terminals across Australia's remote state capitals, stitching the continent together with data lines while most of the world still thought one computer per building was plenty.⁸

Theo: Remember the Nokia episode, how a company can invent the future and still not own it? Feels like Australia kept doing that.

Ada: It really does. And the pattern repeats with the small machines. By nineteen eighty-two, Owen Hill and a firm called Applied Technology launched the Microbee, an Australian-designed Z80 microcomputer.⁸

Theo: A home-grown micro, competing with the imports?

Ada: It won the New South Wales education tenders and filled school computer labs across the country. A generation of Australian kids learned to code on a machine built at home.⁸

Theo: From mercury delay lines to classroom micros, all inside about thirty years.

Ada: And through all of it, the original machine, CSIRAC, was still quietly running in Melbourne, right up until the end.

The Only Giant Left Standing

CSIRAC powered down November 1964

Only intact surviving first-generation computer on Earth

Preserved complete at Scienceworks, Melbourne

Ada: Frank Hirst powered CSIRAC down for the last time in November nineteen sixty-four. And here's what makes it extraordinary.¹³

Theo: Let me guess, everyone else scrapped theirs.

Ada: Every one. ENIAC, EDSAC, the Manchester Baby, all broken down, scavenged or thrown out. But the CSIRO donated CSIRAC complete, paper tapes, consoles, mercury delay lines, punch-card gear, the lot, to Museums Victoria.¹²

Theo: So the one country that walked away from making mainframes is the one that saved the first generation.

Ada: It's the only intact, fully surviving first-generation electronic computer left on Earth. You can stand in front of it today at Scienceworks in Melbourne.¹²

Theo: There's a lovely irony there. The machine Sydney gave up became the one thing nobody else managed to keep.

Ada: That's the whole story in miniature. A team improvised a computer from war junk, taught it to play Colonel Bogey, lost the industrial lead to radio dishes and racehorses and red tape, yet left behind the last giant standing.

Theo: And the people matter as much as the machine. A programmer who debugged by ear, a physicist chasing packet-switching across an empty continent.

Ada: History often remembers the winners of the race and forgets who kept the evidence. Australia lost the race and kept everything. If a question's been nagging at you through any of this, you can interrupt us any time and just ask.

Theo: This was Historai, where history answers back.