Biography of Konrad Zuse, Inventor and Programmer of Early Computers

Konrad Zuse (June 22, 1910–December 18, 1995) earned the semi-official title of "inventor of the modern computer" for his series of automatic calculators, which he invented to help with his lengthy engineering calculations. Zuse modestly dismissed the title, though, praising the inventions of his contemporaries and successors as being equally—if not more—important than his own.

Early Life

Konrad Zuse was born on June 22, 1910, in Berlin-Wilmersdorf, Germany, and was the second of the two children of the Prussian civil servant and postal officer Emil Wilhelm Albert Zuse and his wife Maria Crohn Zuse. Konrad's sister was named Lieselotte. He attended a series of grammar schools and briefly considered a career in art, but he eventually enrolled at the Technical College (Technischen Hochschule) in Berlin-Charlottenburg, graduating with a degree in civil engineering in 1935.

After graduation, he started work as a design engineer at the Henschel Flugzeugwerke (Henschel aircraft factory) in Berlin-Schönefeld. He resigned a year later after deciding to devote his life entirely to the construction of a computer, work that he pursued relentlessly between 1936 and 1964.

The Z1 Calculator 

One of the most difficult aspects of performing large calculations with slide rules or mechanical adding machines is keeping track of all the intermediate results and using them in their proper place during the later steps of the calculation. Zuse wanted to overcome that difficulty. He realized that an automatic calculator would require three basic elements: a control, a memory, and a calculator for the arithmetic.

Zuse made a mechanical calculator called the Z1 in 1936. This was the first binary computer. He used it to explore several groundbreaking technologies in calculator development: floating-point arithmetic, high-capacity memory, and modules or relays operating on the yes/no principle. 

Electronic, Fully Programmable Digital Computers

Zuse's ideas were not fully implemented in the Z1 but they succeeded more with each Z prototype. Zuse completed the Z2, the first fully functioning electro-mechanical computer in 1939, and the Z3 in 1941. The Z3 used recycled materials donated by fellow university staff and students. It was the world's first electronic, fully programmable digital computer based on a binary floating-point number and a switching system. Zuse used old movie film to store his programs and data for the Z3 instead of paper tape or punched cards. Paper was in short supply in Germany during the war.

According to "The Life and Work of Konrad Zuse" by Horst Zuse:

"In 1941, the Z3 contained almost all the features of a modern computer as defined by John von Neumann and his colleagues in 1946. The only exception was the ability to store the program in the memory together with the data. Konrad Zuse did not implement this feature in the Z3 because his 64-word memory was too small to support this mode of operation. Due to the fact that he wanted to calculate thousands of instructions in a meaningful order, he only used the memory to store values or numbers.

The block structure of the Z3 is very similar to a modern computer. The Z3 consisted of separate units, such as a punch tape reader, control unit, floating-point arithmetic unit, and input/output devices.”

Marriage and Family

In 1945, Zuse married one of his employees, Gisela Ruth Brandes. They had five children: Horst, Klaus Peter, Monika, Hannelore Birgit, and Friedrich Zuse.

The First Algorithmic Programming Language

Zuse wrote the first algorithmic programming language in 1946. He called it Plankalkül and used it to program his computers. He wrote the world's first chess-playing program using Plankalkül.

The Plankalkül language included arrays and records and used a style of assignment—storing the value of an expression in a variable—in which the new value appears in the right column. An array is a collection of identically typed data items distinguished by their indices or "subscripts,” such as A[i,j,k], in which A is the array name and ​i, j, and k are the indices. Arrays are best when accessed in an unpredictable order. This is in contrast to lists, which are best when accessed sequentially.

World War II

Zuse was unable to convince the Nazi government to support his work for a computer based on electronic valves. The Germans thought they were close to winning the war and felt no need to support further research.

The Z1 through Z3 models were shuttered, along with Zuse Apparatebau, the first computer company that Zuse formed in 1940. Zuse left for Zurich to finish his work on the Z4, which he smuggled from Germany in a military truck by hiding it in stables en route to Switzerland. He completed and installed the Z4 in the Applied Mathematics Division of Zurich's Federal Polytechnical Institute, where it remained in use until 1955. 

The Z4 had a mechanical memory with a capacity of 1,024 words and several card readers. Zuse no longer had to use movie film to store programs since he could now use punch cards. The Z4 had punches and various facilities to enable flexible programming, including address translation and conditional branching. 

Zuse moved back to Germany in 1949 to form a second company called Zuse KG for the construction and marketing of his designs. Zuse rebuilt models of the Z3 in 1960 and the Z1 in 1984.

Death and Legacy

Konrad Zuse died on December 18, 1995, of a heart attack, in Hünfeld, Germany. His innovations of fully working programmable calculators and a language to run it have established him as one of the innovators leading to the computing industry.

Sources

• Dalakov, Georgi. "Biography of Konrad Zuse." History of Computers. 1999.
• Zuse, Horst. "Konrad Zuse—Biography." Konrad Zuse Homepage. 2013.
• Zuse, Konrad. "The Computer, My Life." Trans. McKenna, Patricia and J. Andrew Ross. Heidelberg, Germany: Springer-Verlag, 1993.