Konrad Ernst Otto Zuse was a German civil engineer, computer scientist, inventor, and businessman. He is best known for creating the world's first programmable computer, the Z3, which became operational in May 1941. This machine, along with earlier models, led some to call Zuse the "father of the modern computer."

Zuse also developed the S2, a computer used to control industrial processes. In 1941, he started one of the earliest businesses focused on computers, producing the Z4, which became the first commercial computer. Between 1943 and 1945, he designed Plankalkül, the first high-level programming language. In 1969, Zuse wrote a book titled Calculating Space, in which he proposed the idea that the universe might function like a giant computer.

At first, Zuse's work was funded by his family and businesses. After 1939, the government of Nazi Germany provided him with resources. However, because of World War II, his contributions were not widely recognized in the United Kingdom or the United States. His first known influence on a U.S. company occurred in 1946, when IBM considered using his patents. The Z4 also inspired the creation of ERMETH, the first Swiss computer and one of the first in Europe.

Early life and education

Konrad Zuse was born in Berlin on 22 June 1910. In 1912, his family moved to East Prussian Braunsberg (now Braniewo in Poland), where his father worked as a postal clerk. Zuse attended the Collegium Hosianum in Braunsberg, and in 1923, the family relocated to Hoyerswerda. There, he passed his Abitur in 1928, which allowed him to attend university.

He enrolled at Technische Hochschule Berlin (now Technische Universität Berlin) and studied both engineering and architecture. However, he found these subjects uninteresting. Zuse then focused on civil engineering and graduated in 1935.

Career

After graduating, Zuse worked for the Ford Motor Company, using his artistic skills to design advertisements. He later became a design engineer at the Henschel aircraft factory in Schönefeld near Berlin. This job required many calculations to be done by hand, which led him to think about creating a machine to perform these tasks.

Starting in 1935, Zuse built early computers in his parents’ apartment on Wrangelstraße 38. Later, he moved to a new apartment on Methfesselstraße 10, near Kreuzberg in Berlin. In 1936, he created his first computer, the Z1, which used binary numbers and could be programmed in a limited way. It read instructions from a 35 mm film with holes punched in it.

In 1937, Zuse submitted two patents that described ideas similar to a computer design called the von Neumann architecture. In 1938, he completed the Z1, which had about 30,000 metal parts. However, it did not work well because the parts were not made with enough precision. On January 30, 1944, the Z1 and his parents’ apartment were destroyed in a British air raid during World War II.

Zuse worked alone without help from other scientists or mathematicians of his time. From 1936 to 1945, he had little contact with others working on similar projects.

In 1939, Zuse was called to serve in the military, where he received resources to build the Z2. In September 1940, he showed the Z2 to experts at the Deutsche Versuchsanstalt für Luftfahrt (DVL), a German research institute. The Z2 was an improved version of the Z1 that used telephone relays instead of mechanical parts.

In 1940, the German government funded Zuse and his company through the Aerodynamische Versuchsanstalt (AVA), which used his work to build glide bombs. Zuse built the S1 and S2 computers, which calculated aerodynamic corrections for flying bombs. The S2 was the first computer with an analog-to-digital converter that could be controlled by a program.

In 1941, Zuse started a company called Zuse Apparatebau to build his machines. He rented a workshop on Methfesselstraße 7 and later moved to Belle-Alliance Straße 29 (later renamed Mehringdamm 84).

In 1941, Zuse improved the Z2 and built the Z3. On May 12, 1941, he showed the Z3 to the public. The Z3 was a binary calculator with 22 bits and could be programmed with loops, though it lacked conditional jumps. It used telephone relays for memory and calculations. The Z3 was a fully operational electromechanical computer, partly funded by the DVL, which wanted to automate complex calculations. A request for government funding to build an electronic version of the Z3 was denied as “strategically unimportant.”

In 1937, a colleague named Helmut Schreyer suggested Zuse use vacuum tubes for his machines. Zuse thought the idea was too strange at the time. In late 1943, Zuse’s workshop on Methfesselstraße 7 (along with the Z3) was destroyed in an Allied air raid. His parents’ apartment, which held the Z1 and Z2, was also destroyed on January 30, 1945. However, the Z4, which Zuse started building in 1942 in a new location, survived.

On February 3, 1945, bombing in the Luisenstadt area near Oranienstraße caused major destruction, stopping Zuse’s work completely. The Z4, a partially finished machine using telephone relays, was moved from Berlin to Göttingen on February 14, arriving about two weeks later.

Zuse’s machines helped develop guided missiles like the Hs 293 and Hs 294, which were early versions of modern cruise missiles. The S1’s design influenced the Z11. Zuse believed these machines were taken by Soviet troops in 1945.

While working on the Z4, Zuse realized programming in machine code was too complicated. He began writing a PhD thesis about the first high-level programming language, Plankalkül, and created the first computer chess engine as an example.

After the 1945 bombing, Zuse left Berlin for the rural Allgäu region. Due to post-war shortages, he could not build computers.

In 1946, Zuse started a company called Zuse-Ingenieurbüro Hopferau. He raised money through ETH Zurich and an IBM agreement for his patents.

In 1947, Alan Turing and Konrad Zuse met in Göttingen during a meeting with other scientists.

Zuse did not resume work on the Z4 until 1949. He showed the computer to Eduard Stiefel of ETH Zurich, and they agreed to loan the Z4 to the university.

In November 1949, Zuse founded another company, Zuse KG, in Haunetal-Neukirchen. In 1957, the company’s headquarters moved to Bad Hersfeld. The Z4 was completed in 1950 and delivered to ETH Zurich, where it worked reliably. At that time, it was the only working digital computer in Central Europe and the second computer ever sold or loaned. Other computers, like the Z11 and Z22, were also built by Zuse and his company.

Zuse could not build new hardware after the war but continued working on Plankalkül. He published parts of his thesis in 1948 and 1959, though the full work was not published until 1972. His PhD thesis was rejected because he did not pay a required fee, but this did not bother him.

Plankalkül influenced the design of ALGOL 58 but was not widely used until 1975. Later versions were developed in 1998 and 2000. Donald Knuth once imagined how history might have changed if Zuse’s thesis had been published earlier.

In 1956, Zuse began working on a high-precision plotter, which was displayed at the 1961 Hanover Fair and became well known.

Personal life

Konrad Zuse married Gisela Brandes in January 1945. He used a horse-drawn carriage for the wedding, wearing a formal suit and top hat, while Gisela wore a wedding veil. Zuse believed the ceremony should be formal and respectful. Their son, Horst, was born in November 1945 and was the first of five children.

Zuse never joined the Nazi Party. There is no record of him expressing any doubts or concerns about working for the Nazi war effort. Later in life, he said that modern scientists and engineers often face a difficult choice: either work for businesses or military groups with questionable goals, or stop working in their field entirely.

After retiring, Zuse focused on painting as a hobby. He signed his paintings with the name "Kuno [von und zu] See."

Zuse did not believe in any religion.

He died on December 18, 1995, in Hünfeld, Hesse (near Fulda), due to heart failure.

Awards and honours

Zuse received several honors for his work:

• Werner von Siemens Ring in 1964 (with Fritz Leonhardt and Walter Schottky)
• Harry H. Goode Memorial Award in 1965 (with George Stibitz)
• Wilhelm Exner Medal in 1969
• Bundesverdienstkreuz in 1972 – Great Cross of Merit
• Computer History Museum Fellow Award in 1999 "for inventing the first program-controlled, electromechanical, digital computer and the first high-level programming language, Plankalkül."

The Zuse Institute Berlin is named after him.

The Konrad Zuse Medal of the Gesellschaft für Informatik and the Konrad Zuse Medal of the Zentralverband des Deutschen Baugewerbes (Central Association of German Construction) are both named after Zuse.

A replica of the Z3 and the original Z4 are displayed at the Deutsches Museum in Munich. The Deutsches Technikmuseum in Berlin has an exhibition about Zuse, showing twelve of his machines, including a replica of the Z1 and several of his paintings.

The 100th anniversary of his birth was celebrated with exhibitions, lectures, and workshops.