Geoffrey Hill

The first demonstration of computer music was made (and it caused quite a stir) during the inaugural Conference of Automatic Computing Machines in Sydney, Australia, held from 7 to 9 August 1951. The program was written by Geoff Hill, a young computer programmer with perfect pitch, and ran on the computer CSIR Mark 1 (later renamed CSIRAC—the CSIR Automatic Computer), the first stored-program computer in Australia.

Geoffrey William Hill (1928–1982), a student in mathematics and physics at the University of Sidney, entered the Sydney-based CSIR (Council for Scientific and Industrial Research) Radiophysics Laboratory in 1949 as a part-time technical assistant to a research group with the goal to design and build an electronic computer (project started in 1947 by Trevor Pearcey, an English scientist, who migrated to Australia in 1945). The machine, referred to as CSIR Mk 1, was to be built using the vacuum tube or valve technology and the pulse techniques developed for radar systems during World War II. The CSIR Mk1 ran its first test programs in late 1949, and it was the fifth electronic stored-program computer ever developed. The machine was officially opened in 1951 and used to solve problems both for the Radiophysics Laboratory and outside organizations.

CSIRAC was a very primitive computer by modern standards. The machine was entirely serial in operation and contained 2000 thermionic valves or vacuum tubes (twin triodes), representing 4000 logic elements. It was very slow (up to 1000 instructions per second), did not have very much memory (about 2KB of RAM and 4KB of disk memory–four 1024 word stores with an average access time of 10 msec), and filled a room and consumed about 30 kW of power, and had no display like a modern computer. Input and output, initially via punched cards, were later changed to hole paper tape, which can be converted to text on another machine. The only familiar output device was a speaker (called the hooter), and it was used to track the progress of a program. Programmers would place a sound at the end of their program so they knew it had ended (this was known as a blurt), or they would program progress-indicator blurts into a program.

The memory of the CSIRAC was mercury acoustic delay lines. That means a pulse would be put into the memory tube, it would travel to the other end of the tube and be recycled back to the front. In this way, many bits and digital words could be stored in one tube of mercury. There were 32 memory tubes and each of these can hold 32 words (a total of 1024 words). A consequence of using mercury acoustic delay time memory was that each memory access took a different time (about 1 msec). This would prove problematic for any time-critical application, such as playing music in real-time.

The melodies played were mostly from popular songs, like: ‘Colonel Bogey’, ‘Bonnie Banks’, ‘Girl with Flaxen Hair’, and so on. The way CSIRAC created sounds was by sending raw pulses from the computer data bus to the speaker. If casually programmed, these pulses would arrive at the speaker at somewhat random times, resulting in the blurting type of sound used by programmers to indicate points in the program’s execution.

Hill would have quickly realized that if he could get the pulses to arrive at a regular time, then he would get a steady pitch. Then, perhaps he could program the notes of a musical scale. This was an exceedingly difficult task because each memory access took a different time, and the overall clock frequency was only 1000 cycles a second.

But Hill managed this, and his musical knowledge was invaluable, although on at least one occasion he telephoned his mother (she was a music teacher) late at night and asked her if some notes were in tune while holding the telephone receiver to the computer speaker. Her response on the first occasion was to scold her son for playing silly buggers with a comb and a piece of paper and annoying her late and night when his dinner was in the oven! She didn’t understand what was going on.

When CSIRAC moved to the University of Melbourne in 1956, it continued to play music. The university’s mathematics professor Tom Cherry wrote a program so that anyone could punch a “score” or “pianola” tape for the computer to play without the intricacies of knowing how to program the hooter.

Biography of Geoff Hill

Geoffrey (Geoff) William Hill was born on 16 February 1928 in Hawthorn, Melbourne, Australia. He came from a very musical family; his mother was a music teacher, his sister a performer and he had perfect pitch. In his younger day, he took part in stage plays.

In 1946 Hill began his study in mathematics and physics at the University of Sidney and worked at CSIR Division of Radiophysics as a student employee, then as a part-time technical assistant from 1949. He graduated in 1950 with BSc (Hons), then in 1954, he received an MSc in mathematics and computing for a thesis entitled Programming for High Speed Computers. In 1961, he was awarded a Ph.D. from the University of Melbourne for a dissertation on Advanced Programming of Digital Computers.

Hill’s professional career had been almost entirely with the Commonwealth Science and Industrial Research Organization (CSIRO). In 1949, while yet a student, he joined CSIRO’s Division of Radiophysics as a part-time Technical Assistant, responsible for the logical design, defining the instruction set and to developing a programming scheme of CSIR Mk1, the first stored-program computer in Australia. In the early 1950s Hill was the main programmer of CSIR Mk1. In 1960 he devised a simple automatic language titled INTERPROGRAM. With INTERPROGRAM, programs could be written in an English-like language. In 1957, he transferred to the Division of Mathematics and Statistics where he worked for 21 years rising to the level of Senior Principal Research Scientist and Acting Chief of the Division. In 1976, he moved into the Division of Mineral Chemistry so he could devote more time to the pursuit of geostatistics.

In 1975, with the assistance of a French Government Scholarship, Hill studied at the Centre de Morphologie Mathematique at Fontainebleau. In 1980, he returned to the Centre again for a period of 6 months for additional studies. During his career, Geoff was a Visiting Scientist and Professor to organizations and universities in the United States, Canada, and South Africa. He contributed to the organization of, and presented papers at many international conferences and published about 40 papers.

Hill was an extremely talented scientist, he never stopped learning and was interested in a wide range of problems, including farm yields, rainfall, library systems, accounting procedures and financial data processing, soils, geomechanics, and forecasting. In addition to serving on editorial boards and reviewing manuscripts for several journals, he belonged to numerous organizations. Included in the list are International Association for Mathematical Geology, ACM, Biometrics Society, Australian Statistical Society, International Statistical Institute, Australian Computing Society, and International Mathematical Statisticians.

Geoff Hill was married to Eilene Hill, and they had three children: a daughter, Elizabeth, and two sons—Peter and Michael.

Geoff Hill died suddenly of a heart attack on 15 November 1982 while returning home from work in his car.