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KF5JRV > TECH 25.05.16 12:52l 73 Lines 4076 Bytes #999 (0) @ WW
BID : 3524_KF5JRV
Read: GUEST
Subj: CSIR Mk 1
Path: IW8PGT<CX2SA<N0KFQ<KF5JRV
Sent: 160525/1131Z 3524@KF5JRV.#NWAR.AR.USA.NA BPQK1.4.65
CSIRAC; Council for Scientific and Industrial Research Automatic Computer),
originally known as CSIR Mk 1, was Australia's first digital computer, and the
fifth stored program computer in the world. It is the oldest surviving
first-generation electronic computer (The Zuse Z4 at the Deutsches Museum
is older, but was electro-mechanical, not electronic), and was the first in
the world to play digital music.
The CSIRAC was constructed by a team led by Trevor Pearcey and Maston Beard,
working in large part independently of similar efforts across Europe and the
United States, and ran its first test program sometime in November 1949.
The machine was fairly representative of first-generation valve-driven
computer designs. It used mercury acoustic delay lines as its primary data
storage, with a typical capacity of 768 20-bit words (later doubled),
supplemented by a parallel disk-type device with a total 1024-word capacity
and an access time of 10 milliseconds. Its memory clock ran at 1000 Hz, and
the control unit, synchronized to the clock, took two cycles to execute an
instruction (later the speed was doubled to one cycle per instruction). The
bus (termed the "digit trunk" in their design) is unusual compared to most
computers in that it was serial—it transferred one bit at a time. The
instruction set 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 proved unsatisfactory. The machine was controlled
through a console which allowed programs to be stepped through one at a time,
and featured CRT displays which showed the contents of registers. Output was
through a standard teleprinter or to punch tape.
The machine, like all machines of the era, had no operating system. A
high-level interpreted programming language 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.
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'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, 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, 6V6,
EA50 diodes and KT66. George Semkiw later redesigned the drum-read
electronics to use germanium transistors.
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[8] 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 history was being lost forever. A conference
about the machine was held in 1996.
The machine found a permanent home in the Melbourne Museum 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 has been written for it. The curators have
decided that, aside from the cost of restoring the device, 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 and is included in a
Heritage Overlay.
See also
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