Alan Mathison Turing He was a British mathematician, logician, theoretical computer scientist, cryptographer, philosopher, and theoretical biologist.
In fact, Alan Turing is one of the great pioneers of the digital age, since he established the mathematical foundations of and used electromechanical digital machines for Germans at Bletchley Park in England during World War II. But one of his contributions that has been overlooked is his pioneering work in transforming the computer into a musical instrument.
It is often said that the computer generated musical notes were heard for the first time in 1957, in the Bell Laboratories, in United States. Actually, the computer at the Turing Computing Machine Laboratory at the University of Manchester in England, already played musical notes many years before.
The beginnings of Alan Turing in the Manchester laboratory
It was in the Manchester laboratory, in June 1948, where the first stored-program electronic multipurpose computer ran its first program. Nicknamed “Baby“, this prototype was somewhat crude. Programs were entered into memory, through a panel of manual switches.
The result were bright dots and stripes on a small glass screen. “Baby” was created by two brilliant engineers (Freddie Williams and Tom Kilburn) as a test bed for their innovative new high-speed electronic memory, the Williams–Kilburn tube (a type of cathode ray tube).
Although Baby ran his first program a few weeks before Turing arrived at the Manchester lab, Turing’s ideas had greatly influenced Kilburn when designing the computer. (Kilburn did not like to credit Turing, but the historical evidence on this point is clear.)
After your arrival, Turing improved Baby’s basic nature, designing an entry-exit system that was based on wartime technology used at Bletchley Park. Williams and Kilburn themselves knew nothing of or of their 9 gigantic Colossus computers.
These secret machines were the world’s largest electronics, although they were not multipurpose and did not incorporate the concept of stored program. Instead, each Colossus was controlled by switches and a patch panel. The war ended before a plan to use a teleprinter tape to control the computer could be tested.
Turing used the same punched tape as the basis for his I/O puncher and reader. As in the case of Colossus, a row of light-sensitive cells converted the hole patterns in the tape into electrical impulses and fed these impulses to the computer. What made Baby unique was that instead of running the program directly from a tape, stored it in memory for execution. (Once programs are stored in internal memory, a computer can edit them before – or even while – they run.)
The Manchester Mark I Machine, the origin of it all
Soon a larger computer took shape in the lab. Turing called it Mark I. Kilburn and Williams worked primarily on and Turing on . Williams developed a new form of supplementary memory (a rotating magnetic drum) while Kilburn took it upon himself to develop the guts of the computer, such as the central processor.
Turing designed the programming system for the Mark I and wrote the world’s first computer programming manual. The Mark I went into operation in April 1949, and further refinement was made as the year progressed.
Ferrantia Manchester engineering firm, was contracted to build a marketable version of the computer, and the basic designs for the new machine were delivered to Ferranti in July 1949. The first Ferranti computer was installed in Turing’s laboratory in Manchester in February 1951 (a few weeks before the first commercial American-made computer became available, UNIVAC I).
Turing referred to the new machine as Manchester Electronic Computer Mark IIwhile others called it Ferranti Mark 1. (He wrote the programming manual in anticipation of the arrival of the Mark II and titled it Programmers’ Handbook for Manchester Electronic Computer Mark IIbut it was based on his programming design work for the Mark I.
Electronic computers that play musical notes?
But… How did Turing turn the Manchester computer into a musical instrument? Its Programmer’s Manual explained it. As far as we know, the Manual contains the first written tutorial on how to program an electronic computer to play musical notes.
The Manchester computer had a loudspeaker called “hooter” which served as an alarm when the machine needed attention. With some additional programming, it could be made the “hooter” emitted a series of musical notes. This was all a trick. To produce a tone from a speaker, an oscillating electrical signal must be sent to it. The frequency of the oscillations gives the frequency of the tone.
Modern digital sound equipment they can generate all sorts of complex oscillating waveforms, but all the Mark II builders could do was send sequences of digital on-off pulses to the speaker.
And this is exactly what the computer’s “hoot” instruction did; executing the instruction once sent a pulse to the “hooter”. But a pulse alone would only produce a sound that Turing described as “something between a tap, a click and a thump“.
A recognizable tone could be played using a program loop to repeatedly execute the hoot command, sending a train of pulses to the hooter. The frequency of the tone was fixed based on the time elapsed between the pulses.
Now comes the smart part. Programmers measure the time it takes a computer to execute an instruction in clock cycles: In order for all its circuits to work in synchrony, a computer has a master clockand it is only at each “ticking” of this clock that the results of one set of are accepted by the next.
Modern computers have clock speeds that are measured in gigahertz, i.e. billions of cycles per second for greater precision).
The Mark II was advancing at just over 4 kilohertz, that is, four thousand cycles per second.
The hoot instruction took four cycles to complete, sending a one cycle long pulse to the speaker on the fourth cycle. The loop instruction also took four cycles, so when looping, the pulse was sent every eight cycles, or at a frequency of 521 hertz, which is very close to the C5 note. (The subscript indicates the octave; middle C is C 4.)
Turing realized that by using multiple hoot instructions within the loop and/or “dummy” instructions that the computer “wasted” cycles executing, it could vary the time between pulses, creating notes with different frequencies. For example, two hoots followed by the loop instruction would produce F4.
Turing himself does not seem to have been particularly interested in programming the machine to play conventional pieces of music. Instead, conceived the different musical notes as auditory indicators of the internal states of the computer:
- A note could sound for “job done”,
- Another for “error transferring data from magnetic drum” or “overflowed digits in memory”, etc.
Running one of Turing’s programs must have been “noisy business”, with different musical notes and click rates allowing the user to “hear” (as Turing put it) what the program was doing. Although it is not really known exactly when the manchester computer played its first programmed note.
Geoff Tootill he was one of the electrical engineers tasked with building the hardware, and his lab notebook is one of the few surviving documents of the Baby’s transition to the Mark I. In the notebook, the Mark I’s 5-digit instruction code for the “hoot” 11110 appears in an entry from October 1948, but it still doesn’t correspond to any instructions (even today, designers put aside code that doesn’t actually do anything, so they can easily add new instructions later). .
But in late November, a notebook entry showed that by then, 11110 had been paired with an instruction. The notebook labeled this new instruction simply “stop”, but the computer already had an instruction to stop (00010), so it seems likely that the new instruction was the special type of stop that was later called “hoot stop“.
The programmer used it for debugging: He inserted a hoot-stop instruction into a program so that the computer would stop at that point in execution. The “hoot” (a steady, continuous C-sharp note) alerted the Mark I operators that the computer had stopped as instructed. Of course, we can’t now conclude with certainty that the hoot-stop idea was actually tested on the computer in November 1948, but if it wasn’t put into practice then, it certainly wasn’t long before Turing and Tootill made it happen. the computer issued its first note.
It took several more years before someone strung together these pioneering notes to create a complete digital piece of music on the Mark II.
Binary code is the musical score of computers.
That someone was Christopher Strachey.which was presented at the Computing Machine Laboratory one summer day in 1951. Strachey soon became one of the most talented programmers in the UK, eventually heading the Programming Research Group at Oxford University.
Strachey was drawn to digital computers as soon as he heard of them, that was in January of 1951, more or less. Before the war, he had met Turing at King’s College, Cambridge, and in April 1951 he wrote to him about the manchester computer. Turing sent him a copy of the Manual from him, and Strachey studied it with interest.
The Manual was “famous in those days for its incomprehensibility,” Strachey said.
This incomprehensibility was largely due to the way in which Turing had incorporated the conventions of the tape drive into the system software. Turing used a variant of the international teleprinter code to abbreviate the computer code instructions.
, in use for decades at the time, associates letters, numbers, and other characters with 5-bit strings; for example, A is 11000 and B is 10011 (it’s the predecessor of the , which are used today to store text digitally).
The teleprinter code was well known to engineers at the time; Turing was very familiar with him from his wartime work at Bletchley Park cracking the cipher of…
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