An Electronic Computer

The possibilities for a relay computer looked optimistic when Schreyer sud­denly suggested using electronic valves instead. Though they were not then commonly employed for switching be­tween two states, valves could be used in that way and would be far faster than relays. "At first I thought it was one of his student jokes – he was always full of fun and given to fooling around", Zuse has recalled.

About 2000 valves would be needed. Asking for them, and getting them, were two different things in a Germany then at war. Private enterprise stood no chance4 so they talked to the German Army Command. Whilst the initial reaction was favourable, the idea foundered when they said it would take about two years to build. "And just how long do you think it'll take us to win the war?" they were asked.

So little help came, but by the end of the war Schreyer had built an ex­perimental computer with just 100 to 150 valves, and gained his doctorate on the way for his work on valve switching circuits. Like the other computers, this too was a casualty of the war. After the war the development of electronic equipment was banned in Germany and so Schreyer emigrated to Brazil. It was there that he died in 1985.

Whilst Schreyer worked part–time on the electronic machine Zuse completed the electromagnetic relay computer, the Z3, encouraged by the Experimental Aircraft Institute. The Z2 had con­vinced the Institute of the usefulness of Zuse's ideas and so it financed the Z3, though Zuse still had to work alone and at home. And he had to escape a recall to active duty for service5 on the Eastern Front.

The Z3 was the first general–purpose digital computer in the world. It was completed in 1943. It employed binary numbers, floating-point arithmetic and a 22-bit wordlength, and it has been estimated that it used around 2000 re­lays (and eight uniselector switches) and cost the equivalent of between $6000 and $7000. "The most important thing", says Zuse, "seemed to be to keep the frequency absolutely even, so that one cycle equaled one addition". This he achieved using a rotating disc or roller, each revolution defining one operation. As the disc's speed could be varied, so too could the operating speed of the computer. Sparking at the relay con­tacts was eliminated by making or breaking them before any current flowed, so increasing reliability. Post­war Zuse machines are said to have been "legendary" for their reliability."

Although the Z3 was completed (with the help of friends) it served mainly as an experimental machine and it never went into routine use probably because of the limited capacity of its memory. There are no doubts, however, that it was fully functional, because there are several witnesses to its operation. Though the original Z3 was blitzed out of existence6 a reconstruction was made years later, based on the surviving patents, and is now in the Deutsches Museum in Munich.

The Survivor

Somehow Zuse found time to build other computers as well. The S1 was a non-programmable machine using hard-wired programs. It served in the design of the Henschel flying bomb HS-293, a pilotless aircraft guided by radio from a bomber. It replaced a dozen calculators. An improved design, the S2, was too late for routine service and is the one that Zuse thinks might have been captured by the Russian army. But the big one was the Z4: a full-sized general-purpose computer, the only one to survive the war.

After the War

Zuse continued to develop his ideas for computers and planned what was prob­ably the first algorithmic computer lan­guage. The game of chess served as a test subject.

In 1949 he re-established his own firm which became known as Zuse KG. With contracts initially from Switzerland and then Germany the firm prospered and for many years was second only to IBM in Germany. The Z series continued with relay computers and then fully electro­nic machines. The last of the relay machines was the ZII which became a byword for reliability8. As competition grew, and technology changed, so life got tougher and outside funding was required. This eventually led to the company's being absorbed by Siemens.

Zuse is still a consultant; but even more he is a painter, whose work had been described as "a synthesis of ex­pressionism and surrealism, in brilliant colours". One engineering task that he did take up in the 1980s, however, was to rebuild the ZI from memory – as a museum piece.

Task I

Comment on Zuse’s words ” Necessity was no the mother of inventions, it was laziness and boredom: the desire to rid himself of those tedious calculations.”

Task II

Speak on history and characteristics of Z1.

Task III

Describe other Zuse’s computers.

RUDOLPH KOMPFNER

(1909-1977)

“There is nothing like a goodly amount of dissatisfaction and unhappiness to bring on invention.”

TWTs have been used in a variety of electronic applications and are part of the farthest flung [13] human machines, spacecraft, which are becoming mankind's first interstellar ambassadors.

The travelling-wave tube was invented by Kompfner in his spare time. Officially, he was working at the University of Birmingham as part of the war effort in World War II, trying to improve the klystron amplifier for use in radar receivers. It was in the same department that Randall and Boot invented the cavity magnetron. Whilst Kompfner's official work was leading nowhere, his evening hobby was heading for the jackpot. As Kompfner himself wrote, "I must emphasise again that all this work was carried on outside the laboratory; it was, so to speak, my spare-time amusement."

Architect

Kompfner was known as Rudi. "Few who knew him knew him as Kompfner or Dr Kompfner, and none as Rudolph," says J. R. Pierce, the American physicist who worked with him for many years. Rudi was born on the 16th May, 1909 in Vienna, the elder child, and only son, of Bernhard Kompfner and his wife Paula Grotte. Bernhard was an accountant, but also an accomplished musician who composed Viennese songs and waltzes. Rudi inherited a lifetime love of music.

World War I raged whilst Kompfner was a young boy and Vienna was blockaded. Suffering from malnutrition[14], he was evacuated by the Red Cross and put on a train to Sweden. His parents, apparently, did not know exactly where he was and it must have been a nightmare for them and for him. World War II was also to have troubles in store, but before that there were happier times. He graduated in 1931 from the Technische Hochschule in Vienna with a degree in engineering (architecture). Two years later, in his mid twenties, he completed his studies of architecture in Vienna.

The 1930s were dangerous times for Jews in Austria, but Kompfner had a cousin in England. Her husband helped him to get to England in 1934 and then found him a job. From 1936 to 1941, Rudi Kompfner was the managing director of Franey's building firm.

By that time, Kompfner's interest had been well and truly awakened in physics, as well as architecture. In fact, it would appear that architecture was never his first choice; it has been dictated by his father. His interest in physics, however, was self-generated and was sparked by the writings of the French physicist Arago, an early 19th century contemporary of Ampere.

One oft-repeated 3 story of Kompfner's training as an architect is worth one more repetition because it has a lesson for anyone. Kompfner had been told to design a house and he sat and stared at his blank sheet for hours without drawing a stroke. "An infinity of possible solutions to the problem occurred to me, but I could not see why I should single out any particular one by starting with it." A senior arhitect came to help and simply drew a square. When Kompfner objected to the square as an unlikely shape for a house it was changed. When the change was criticised it, too, was changed, and so on. Gradually an acceptable design evolved. "The secret of starting," he had learned, "is to start." "Starting means at least doing something."

Internment

Once in London, Kompfner pursued his love of physics4 by visiting the Patent Office library in the evenings and reading publications. In 1935 he started to keep notebooks in which he recorded his ideas and two years later he received his first patent for a television pickup device. He tried to market it, but without success. Also in 1935, another love of his life developed when he met Peggy Mason at the Westminster swimming club; Kompfner was a keen swimmer. They married on the 29th April, 1939 and subsequently had two children, a boy and a girl.

One day in June, 1940, Peggy returned home from work to find that her husband had been taken to Brixton police station and interned as an enemy alien5. His internment was spent on the Isle of Man where he shared quarters with Wolfgang Fuchs, the mathematician. Apparently, they talked about physics.

Kompfner's internment was thankfully short. Before he was detained he had sent a paper on magnetrons to the magazine Wireless Engineer, the editor of which had brought the paper to the attention of the Admiralty. Kompfner had meanwhile declared himself to be stateless6 and friends were petitioning for his freedom. He was duly released in December, 1940, after six months. Then, "I was more or less drafted to the physics department of the University of Birmingham," Kompfner wrote in 1964. It was there, under the guidance of Professor Mark Oliphant, that the Admiralty had set up a secret research group with the task of making a practical centimetre radar system. Kompfner arrived in 1941 and within two years had invented the travelling-wave tube.

Date: 2015-12-24; view: 770