Cabinet holding the clock and control circuitry for CSIRAC (formerly CSIR Mk 1).

This cabinet controlled all the operations of the computer.

This circuitry provided all the timing to co-ordinate the operations of the different elements of the computer. CSIRAC could run at up to 500 instructions per second.

The circuitry in this cabinet was a key focus for several successful attempts to increase the speed of the machine.

The control circuitry controlled a number of circuitts including an interpreter for instructions, a sequence register, source and destination register, and a time selector.

CSIRAC at Melbourne consisted of two rows of cabinets, a control console, input and output devices, test equipment and an off-line paper tape editing area. There were nine cabinets, five in the front row and four in the back. Cool air was blown up through all the cabinets from the basement below. The auxiliary memory (disk drive) occupied the space that would have been occupied by a cabinet in the back row.

The five front row cabinets contained (from left to right viewed from the front) power supplies, input and output circuitry, clock and control circuits, arithmetical circuits and memory control circuits. The four back row cabinets contained (from left to right viewed from the front) power supplies, auxiliary store control circuits, 'disk drive', auxiliary test power supplies and memory control circuits.

The date range (1949-1964) is given to indicate that, although the metal cabinets were first used in 1949, changes were made to the structure and circuitry over the period of CSIRAC's working life.

Physical Description

Grey metal cabinet. It has doors on the front and the back. It now sits on a purpose built collection management stillage.


CSIRAC was the fourth stored program computer in the world and the first one in Australia. It is the only intact first generation computer left on the planet.

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