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= CSIRAC =
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Introduction
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CSIRAC (; 'Commonwealth 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.
After being exhibited at Melbourne Museum for many years, it was
relocated to Scienceworks in 2018 and is now on permanent display in
the Think Ahead gallery.
A comprehensive source of information about the CSIRA collection, its
contributors and related topics is available from Museums Victoria on
their Collections website.
History
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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
(multiplication of numbers) sometime in November 1949. In restricted
operation from late 1950, publicly demonstrated and operational in
1951.
Design
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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,
supplemented by a parallel disk-type device with a total 4096-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.
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.
Input to the machine was performed in the form of punched 3 in wide,
12-track paper tape, after experiments with punch cards proved
unsatisfactory. The machine was controlled through a console which
allowed programs to be stepped through one instruction at a time, and
featured CRT displays which showed the contents of registers. Output
was through a standard teleprinter or to punch tape.
The instruction set 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). Instructions consisted of
three components: a 5-bit "destination" P1-P5, a 5-bit "source"
P6-P10, and a 10-bit "address" P11-P20. For instructions that used the
main store, the six bits P15-P20 selected one of the 64 logical delay
lines. Bits P11-P14 determined the time at which 20 bits of data were
written to or extracted from the delay line, and thus represented
address of a word within the selected delay line. There were 32
destination gates and 32 source gates; the 10 address bits identified
a data word within the store if either the source or destination
required access to the store. The total number of source and
destination combinations, or different instruction functions, was
1024, although only about 256 of these were used often. The machine
had three 20-bit registers (A, B and C), two of which were involved in
multiplication, one 10-bit register which could link to either half of
a word, and a group of 16 20-bit registers, addressed via bits
P11-P14. In addition the 20-bit program counter (S register), and the
instruction register (K) were accessible.
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 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.
CSIRAC, side view
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.
Preservation
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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
(later the Caulfield Campus of Chisholm Institute of Technology, and
later again the Caulfield Campus of Monash University) 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 ageing and history was being lost
forever. A conference about the machine was held in 1996.
The machine found a permanent home with Museums Victoria 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.
After being exhibited at Melbourne Museum for many years, it was
relocated to Scienceworks in 2018 and is now on permanent display in
the Think Ahead gallery.
CSIRAC is listed on the Victorian Heritage Register and is included in
a Heritage Overlay.
It is listed as a National Engineering Landmark by Engineers Australia
as part of its Engineering Heritage Recognition Program.
See also
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* Computer music
* Electronic music
* History of computing hardware
* List of vacuum-tube computers
* SILLIAC - Sydney University's second computer
References
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;References
*
;Bibliography
*
*
*
* [
https://pearcey.org.au/csirac/ Alt URL] – A timeline and history
of CSIRAC, as well as a collection of presentations from the 1996
conference on the machine.
*
External links
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* [
http://www.cis.unimelb.edu.au/about/csirac/ CSIRAC homepage] — From
the Computation Laboratory at the University of Melbourne's Department
of Computing and Information Systems
* [
http://www.nationaltreasures.com.au/treasures/computer/ Australian
National Treasure -- CSIRAC] — Television segment on CSIRAC
* [
https://csiropedia.csiro.au/the-computer-csirac-1965/ The Computer
'CSIRAC'] — 1965 film
* [
http://www.audionautas.com/2011/09/music-of-csirac.html The Music
Of CSIRAC] — Paul Doornbusch's book review (in Spanish)
[
https://translate.google.com/translate?sl=auto&tl=en&js=y&prev=_t&hl=en&ie=UTF-8&u=http%3A%2F%2Fwww.audionautas.com%2F2011%2F09%2Fmusic-of-csirac.html&edit-text=
Google translation]
* [
http://www.billp.org/CSIRAC CSIRAC Emulator in Java] — Description
of Architecture, Programming details, and a Java Emulator
* – Trevor Pearcey interview, MP3s of all of the music played by
CSIRAC
*
*
*
License
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Original Article:
http://en.wikipedia.org/wiki/CSIRAC
