June 22 and 23 this year mark the birthdays of two pioneers of computing: Konrad Zuse and Alan Turing. The Turing centenary is an occasion to remember the man who laid the groundwork for many theories of computation, and whose work at Bletchley Park in the UK was crucial in the allies winning the war. Less well known is Zuse, but it was in fact this man, a civil engineer working independently in a Germany under Nazi rule, who built the world's first electrically driven, programmable computer that counted in binary.
The theory came first
Alan Mathison Turing was born in Maida Vale, London, 100 years ago, on 23 June 1912. Turing is often referred to as the Father of Modern Computing. He was a mathematician, with a talent for providing neat, conceptually simple solutions to overarching problems in theories of logic. He was specifically interested in tackling the problem of being able to decide-from a logical perspective-whether mathematical problems were computable or not.
It was a problem that had challenged leaders in the field for decades. Turing advocated logical formalism in his approach but, unlike his contemporaries, was able to express his system in terms of hypothetical 'machines' that could perform any operation on a number. Though these machines didn't physically exist, they established computation as a something that could be carried out as a physical act, just as early computers were beginning to find physical form.
The computer's code breaking roots
Largely unknown at the time due to secrecy underpinning his involvement in the war effort, Turing and his ideas would be crucial in helping the allies in their fight against Nazi Germany. His work in cryptanalysis-codebreaking-was revolutionary, and within weeks of joining the code-breaking team at Bletchley Park, he had improved upon design of the bomba kryptologiczna, a Polish machine for decoding the German Enigma code.
The Enigma machine gave the Germans a stark advantage during World War II: constant improvements to the code's security meant the allies didn't know how to interpret the codes and hence didn't know what the enemy planned next. It encoded a message that was sent to other Enigma machines, relying on a cypher that changed daily. Once received, the message was decoded. Here Turing's familiarity with logic came to the fore: he realized that what he termed 'contradictions' - which resulted from mismatched interpretations of a piece of text - made it possible to deduce the day's Enigma settings by discarding those settings that made contradictions. Eventually, this and other breakthroughs would give the allied codebreakers the information they would need to know the enemy's plans.
The Royal Mail, the relay, and the German engineer
Turing also introduced Royal Mail telephone engineer Tommy Flowers to Max Newman, who was heading another team trying to break another German code. Flowers and Newman would later build the world's first purely programmable electronic computer, Colossus, in 1943. Eventually, Flowers built Colossus using valve technology, but his work for the Royal Mail would have introduced him to all manner of switching systems for telephone exchanges, including the then-ubiquitous electric relays-simple switches that could be used to route telephonic communications. It was with these switches that German civil engineer Konrad Zuse set out building computers, starting with the flawed Z1 in 1936 and perfecting his design with the Z3 in 1941.
Zuse's motivation was born from frustration: he spent far too long, he thought, performing tedious calculations instead of actually solving engineering problems. He did so without state help: the Nazi administration had assessed his work as being unimportant. Nevertheless, the historical record can be unkind to those from the losing country, even if there is no basis for associating Zuse's work with those who had been in power. Maybe that's why so few outside of Germany are aware of his work.
Why binary is better than decimal
Born 102 years ago on 22 June, Zuse was two years and a day older than Turing. Unlike the young Turing, the adolescent Zuse was drawn to artistic pursuits. He painted exquisitely and made elaborate wood cut prints; work he continued all his life alongside his development of computer technology. It is not such a huge leap to imagine that in the workings of the Z3's electromechanical relays-with their clatter of metal on metal-Zuse found familiarity; an echo of the simplicity and reliability of inked wood pressed on paper.
The machine itself encapsulated several breakthroughs: it could do floating-point math (crucial for engineering purposes) and it worked in binary. This last idea was the kind of innovative synthesis of theory and pragmatism born of genius, combining Boolean algebra-which consists of AND, OR, NOT, NOR operators-and its simplest mechanical implementation: the on/off switch. Other computers tried to do everything in decimal. But, when each 'bit' had to hold 10 digits, 10 switches were needed to encapsulate a single digit, which made them much more unwieldy and less reliable than Zuse's simpler binary design.
Though the original Z3 was destroyed in the war, a replica built in 1997 proved that it was Turing-complete: given enough time, it could solve any computable mathematical problem. But the inspiration for Zuse was always to free up time, allowing engineers like him to be more creative.
After the war, Turing embarked on what, from the perspective of history, looks as if it could have been his most promising and creative intellectual work: a theory of biology derived from physical theories of diffusion and chemical reaction. Nowadays, we would call it computational biology. At a time before the biological hereditary unit was recognized in the DNA double helix, Turing was able to postulate a theory of morphogenesis - biological development-remarkably close to what biologists working in the field of epigenesis would discover 50 years later. He was also using computers to 'do' science-specifically, life science. It was e-science long before anyone would think of the term.
During this period, when his mind seemed to be truly blossoming, Turing became the victim of a terrible betrayal and a further injustice that would leave him broken. Reporting a burglary at his home in Manchester he would subsequently admit to having had a prior sexual relationship with the man who had broken into his house. Homosexuality was illegal in the UK, and Turing was arrested for gross indecency. In 1952, he was chemically castrated by estrogen injection, the results of which left him deeply depressed.
Alan Turing had played an important part in freeing Europe from the tyranny of fascism. The importance of his work was acknowledged in 1945, for services unspecified (his work was still a state secret), but now he was the victim of a law derived from bigotry. It was a terrible irony that this tragedy could befall someone who had done so much for his country. In 1954, his cleaner found him dead, clutching an apple laced with cyanide; it was straight out of the film Snow White, which he adored. In 2009, Prime Minister Gordon Brown finally apologized for the injustice, calling it "appalling."
Konrad Zuse escaped attention from the Nazi administration, and was no doubt thankful for it. He went on to live a long life, building computers and later returning to art with renewed vigour. At a closing keynote at the EGI Community Forum 2012 in Munich, Konrad's son Horst Zuse recounted a touching story about his father. Before he died in 1995, Konrad Zuse had the chance to meet Bill Gates and to give the Microsoft founder a portrait he had painted of him. He probably didn't tell Gates, but by all accounts Konrad Zuse wasn't particularly keen on the GUI-based PC. For him, computers were wonderful physical machines; the result of great engineering, persistence, and vision, in whose clattering relays he found a solution to freeing the mind from tedious calculations. In his own words: "I was lazy….so I built the computer."