Konrad Zuse's Z3, the World's First Programmable Computer, Was Unveiled 75 Years Ago

75 years ago today, a German scientist named Konrad Zuse changed computing forever. His invention, the Z3, was presented at the German Laboratory for Aviation in Berlin on May 12, 1941, as the world’s first entirely automatic computer controlled by programs.

The Z3 revolutionized computing. It was used to help calculate aerodynamics in aircraft design, which the UK’s Centre for Computing History says helped the German Aircraft Research Institute in its analysis. We’re used to today’s computers reading programs from solid state storage, but the Z3 read its programs off of punched film.

It’s unlikely that Zuse ever envisioned a world where computers would one day help people crush virtual candies while standing on subway platforms (on the other hand, we also don’t have any evidence to suggest that he didn’t think that), but that’s ultimately where the Z3 has taken us.

You’d expect the inventor of such an important milestone to have a very mathematical worldview, but in his childhood, Zuse was more interested in painting. “I have always had a predominantly visual approach to my environment,” Zuse told The New York Times in 1994. “This perhaps one-sided talent was also evident in the construction of my computer models; here, too, I preferred mechanical and electromechanical constructions and left the electronics to others who were better qualified.”

Zuse spent years working in his parents’ living room, constructing giant computers that would seem ridiculously large by today’s standards. The Z1, an earlier attempt that laid the groundwork for the Z3, was over six feet tall.

The Z1 broke ground in its own right. The Z1, completed in 1936, was the first computer that ran on binary, a series of on and off switches. Unfortunately, it was kind of unreliable and only worked for a few minutes as the mechanical switches would get stuck. The Z3, however, was fully functional. It was built with electrical telephone relays instead of the mechanical switches of its predecessor.

What’s perhaps most interesting about Zuse’s invention is he built it in relative isolation. Howard Aiken, backed by IBM, was working on a similar project at the same time in the U.S. Because of World War II, however, the two men didn’t know about each others’ work. Aiken’s machine, the Mark I, debuted three years after Zuse’s and was reportedly slower.

For many years afterwards, computers remained the domain of military hardware and complex scientific calculations. In 1951, the Ferranti Mark I, based on a design built at the UK’s Manchester University during the war, became the first commercially sold general purpose computer. IBM was one of the key pioneers of early computer development, but lost its hold on the personal computer markets, eventually culminating in the sale of its personal computer business to Lenovo in 2005.

Unfortunately, Zuse’s original Z3 was destroyed in 1943, bombed in Berlin. Also lost in the bombing were important documents associated with its development. Rubbing more salt in the wound, the German Patent Office told Zuse after the war that he could not patent his invention.

Zuse worked on reconstructing the Z3 in the sixties, however, and today that replica is on display in Munich’s Deutsches Museum.