Computer music

Abstract

One of Turing’s contributions to the digital age that has largely been overlooked is his groundbreaking work on transforming the computer into a musical instrument. It is an urban myth of the music world that the first computer-generated musical notes were heard in 1957, at the Bell Laboratories in the United States. In fact, computer-generated notes were heard in Turing’s Computing Machine Laboratory at Manchester University about nine years previously. This chapter establishes Turing’s pioneering role in the history of computer music. We also describe how Christopher Strachey, later Oxford University’s first professor of computing, used and extended Turing’s note-playing subroutines so as to create some of the earliest computer-generated melodies. A few weeks after Baby ran its first program (see Chapter 20) Turing accepted a job at Manchester University. He improved on Baby’s bare-bones facilities, designing an input–output system based on wartime cryptographic equipment (see Chapter 6). His tape reader, which used the same teleprinter tape that ran through Colossus, converted the patterns of holes punched across the tape into electrical pulses and fed these to the computer. The reader incorporated a row of light-sensitive cells that read the holes in the moving tape—the same technology that Colossus had used. As the months passed, a large-scale computer took shape in the Manchester Computing Machine Laboratory. Turing called it the ‘Manchester Electronic Computer Mark I’ (Fig. 23.1). A broad division of labour developed that saw Kilburn and Williams working on the hardware and Turing on the software. Williams concentrated his efforts on developing a new form of supplementary memory, a rotating magnetic drum, while Kilburn took the leading role in developing the other hardware. Turing designed the Mark I’s programming system, and went on to write the world’s first programming manual. The Mark I was operational in April 1949, although additional development continued as the year progressed. Ferranti, a Manchester engineering firm, contracted to build a marketable version of the computer, and the basic designs for the new machine were handed over to Ferranti in July 1949. The very first Ferranti computer was installed in Turing’s Computing Machine Laboratory in February 1951 (Fig. 23.2), a few weeks before the earliest American-built marketable computer, the UNIVAC I, became available.