3. The world’s the first freely programmable computer was invented in Nazi Germany, before being destroyed in an Allied bombing
The Z-series computers, comprising the Z1, Z2, Z3, and Z4, were a series of mechanical computers designed by Konrad Zuse between 1935 and 1943. The Z1, originally called “VersuchsModell 1” (Experimental Model 1) but changed post-war due to confusion with the aforementioned V1 flying bomb, was designed between 1935-1936 and constructed from 1936-1938 in the living room of Zuse’s parent’s apartment. Weighing approximately 1000 kilograms and consisting of roughly 20,000 working parts, the Z1 contained almost all the components of a modern computer including memory, a control unit, and logic devices; this made the Z1 freely programmable via punched tape with pre-programmable memory downloaded onto the internal memory of the machine. Unfortunately, the landmark invention was destroyed during an Allied bombing raid on Berlin in December 1943 along with the plans; despite this, over forty years later Zuse successfully rebuilt his machine in 1989 from memory for the purpose of historical preservation.
The Z2 was only a minor improvement on the Z1, using the same mechanical memory setup but introducing electrical relay circuitry; all existing plans for the Z2 were destroyed during the war. The Z3 was completed in 1941 as the first digital computer in the modern sense, but was not considered sufficiently important to the war effort to be put into operation; in fact, Zuse’s request to replace the computer’s relays with fully electronic switches was denied by the Reich on the grounds it was “not war-important”. Destroyed on December 21, 1943, also during an Allied bombing raid, a replica reproduced in the 1960s demonstrated the machine to be Turing-complete – the first computer to achieve this status.
Unlike his other creations, Zuse was able to rescue one Z4 from the bombings, being evacuated from Berlin in February 1945 to safety in the alpine village of Hinterstein with the machine; it would become the world’s first commercial digital computer in the 1950s. It is also worth noting that in addition to his creation of some of the first modern computers, Zuse was also responsible for the design of the first high-level non-von Neumann programming language: Plankalkül. Developed for his doctoral dissertation, but only published in 1948 due to the fall of Nazi Germany impeding his PhD progress, Zuse developed a system of notation for algorithms during his downtime as he was unable to continue work on the Z4 from remote Hinterstein.