The Music

The first programmers of the CSIR Mk1 were Geoff Hill and Trevor Pearcey. Geoff Hill had perfect pitch and came from a very musical family. Hill was the first person to program the CSIR Mk1 to play a musical melody. It was played publicly for the first public exhibition of the computer on the 7th to 9th of August in 1951, at the inaugural Conference of Automatic Computing Machines in Sydney.

The sound production technique used on the CSIR Mk1 was as crude as is possible to imagine on a computer. Raw pulses of the computer's data words were sent to an audio amplifier with a speaker attached. However, this occurred when there were no digital-to-analog converters, there was no digital audio practice and little in the way of complete digital audio theories. In addition, the CSIR Mk1 produced music in real-time.

The musical pieces played by the CSIR Mk1 are not as musically inspiring as they might have been if composers had been involved in creating the music. The computer had a lot to offer composers of the time, any frequency and any rhythm could have been programmed so the many composers interested in microtonal works, or music with no rhythm or very complex rhythms, could have created some very interesting music. Now, the music is most interesting from the point of view of the application of computers to music as a general principle and for the early practice of computer programming to create music. The achievement is significant because of the imagination of the practitioners, to conceive of using the flexibility of a digital computer to make music and because of the ingenuity required to devise means to produce reliable sounds from the computer. It is difficult to appreciate now just how skilful these people were. It is significant that it was only two of the best programmers who managed to program the CSIR Mk1 to play music.

The CSIR Mk1 operated in Sydney Australia from about November 1949 to June 1955. Geoff Hill was the main programmer at that time and he used the machine to play musical melodies. These melodies, mostly from popular songs, were; 'Colonel Bogey', 'Bonnie Banks', 'Girl with Flaxen Hair' and so on.

The CSIR Mk1 was dismantled in mid 1955 and moved to The University of Melbourne, where it was renamed CSIRAC. Professor of Mathematics, Thomas Cherry, later Sir Thomas Cherry FRS, had a great interest in programming and music and he created music with CSIRAC. In Melbourne the practice of how CSIRAC was programmed for music was altered and refined somewhat. The program tapes for a couple of test scales still exist, along with the popular melodies 'So early in the Morning' and 'In Cellar Cool', which was a popular drinking song - it appears that the pursuit of computer music and social drinking have been intimately linked since the earliest years. There was also other music on the tape. In about 1957 Cherry wrote a music performance program that would allow a computer user who understood simple standard music notation to enter it easily into CSIRAC for performance, without negotiating all of the timing problems such as was normally required. The music itself may now seem very crude unless it is understood in the context of its creation. It was created by engineers who were not knowledgable of the latest in musical composition practice and at a time when there was little thought of digital sound. The idea of using a computer, the world's most flexible machine, to create music was a leap of imagination at the time. It is a pity that composers were not invited to use CSIRAC, as they were with the Bell Labs developments, to discover how it could have solved several compositional problems.

Here is an image (120KB) of the instructions for Cherry's Music Programme.

Here is an image (112KB) of the first page of Cherry's private notes for the Music Programme.

Here is a clipping (84KB) of CSIRAC playing Colonel Bogey (c.1951) and here (360KB) CSIRAC plays In Cellar Cool with a simulation of CSIRAC's room noises.
NOTE: Apple QuickTime 4 is required for playing the music.

Music Reconstruction

The music played by CSIRAC was never recorded onto any audio storage format. Little was known about the music, but several people who had heard from 1951 to the mid1960s were still around to tell of it even though it could not be heard any more. A plan was developed to reconstruct the music. Three essential people who would be needed for this endeavour, Ron Bowles, John Spencer and Jurij (George) Semkiw, were currently involved with a project at the University of Melbourne to document CSIRAC. John Spencer was a programmer on CSIRAC who remains highly skilled with CSIRAC programs and he has also written a comprehensive emulator for CSIRAC. Ron Bowles and George Semkiw were CSIRAC maintenance engineers who have intimate experience and undocumented knowledge of the internal workings of the machine.

Ron Bowles, John Spencer and Jurij Semkiw examining the Sydney music punched paper tape for the first time.

The music was to be reconstructed as exactly as possible, to within an accuracy of better than one percent of the waveforms that would have been heard at the time the pieces were originally played. The pulse shapes, as reproduced, are well within one percent accuracy of the CSIRAC pulse shape, but the pulse timing is at least 10 times more accurate than that. This waveform accuracy would ensure a listening experience faithful to the original and would also ensure that any technical analysis of the waveform would be valid. The best reconstruction of the music was achieved by separating the reconstruction of the timing of the pulses from the reconstruction of the pulse shapes. The course of action taken was; read the program and data tapes (and get them working, a non-trivial matter), use several programs John Spencer developed from his emulator to generate the speaker pulse timing data, build hardware (some with valve technology) to reproduce the pulse shapes that appeared at the speaker terminals, combine these to reproduce the pulse stream. This pulse stream could then be played through the original speaker and recorded.

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