World's oldest working computer reunited with its long lost user manual

Germany's Zuse Z4 was built in 1945, but has long been inoperable without its missing manual.

For decades a secreted away, early digital computer from Nazi-era Germany has long sat dormant within Munich's Deutsches Museum, its operations largely a mystery to historians who required a missing user manual to operate it. Earlier this summer, however, researchers finally rediscovered that very key to cracking the Zuse Z4's outdated technology amidst a pile of historical Swiss aircraft documents.

Konrad Zuse, computer inventor / definitely not a Bond villainpicture alliance/picture alliance/Getty Images

So close, yet so far from operational — For decades, curious historians could essentially look but not touch the Z4. The room-sized machine running on magnetic tapes and requiring multiple operators was largely beyond the grasp of modern researchers due to a missing user manual that was key to understanding the comparatively ancient invention. Earlier this year, however, an ETH Zurich University archivist named Evelyn Boesch discovered a copy of the missing user manual among the affects of her late father, René Boesch, a Swiss aircraft researcher during the 1950's.

A backstory worthy of a spy thriller — At the time of its development, the Zuse Z4 was a powerhouse computer, not to mention the last of its kind to be produced by the Nazis via the machine's namesake inventor, Konrad Zuse. Towards the end of World War II, as Allied forces advanced on Germany, the Nazis attempted to transfer Zuse and his Z4 to Mittelbrau Dora, a concentration camp whose prisoners were then building V1 and V2 rockets. Zuse fled south with his Z4 to a small farm town where he hid his creation in a barn until the end of the war. Afterward, Zuze's Z4 eventually ended up in use by the Swiss Federal Institute of Technology's (ETH) Institute of Applied Mathematics, where it was employed to aid in aircraft development, including the P-16 fighter jet. This is most likely how Evelyn Boesch's father came into contact with the computer.

"Around 100 jobs were carried out with the Z4 between 1950 and 1955,” Herbert Bruderer, a retired ETH Zurich lecturer on computer science didactics, wrote for the organization's blog. “These included calculations on the trajectory of rockets," and other operations totaling over 800 hours of work.

The happy discovery will certainly help researchers gain a better understanding of one of the world's first commercial computers, and definitely gives us a better perspective on just how far we've come with the technology. The Zuse Z4 is cool... just don't try to compare it to Honeywell's quantum computer, or hell, even this portable DIY device.