Konrad Zuse and his Computing Machines

This article will discuss the computing machines Z1 until Z4, which where designed and built by Konrad Zuse between the mid-30ies and the mid-40ies of the 20th century. From scratch Zuse developed fundamental concepts for computer architecture and materialized them in the mechanical though unreliable Z1. Consequently, he migrated his controls step by step to electro-magnetical relays and first built the prototype Z2, followed by the Z3, the first reliable programmable computer. In the following years until the end of World War II, Zuse refined his architecture and built the successor Z4, whose architecture is less known. The architecture and mode of operation of these machines is the main subject of this article. Further we will annotate a few biographical aspects.