Today considered the Z1 is the first freely programmable computer of the world using
Boolean logic and binary floating point numbers. It was completed in 1938 and financed
completely from private funds. Konrad Zuse's first computer, built between 1936 and
1938, was December 1943 destroyed in the bombardment of Berlin in WW II, together
with all construction plans. In 1986, Konrad Zuse decided to reconstruct the Z1.
The Z1 contained almost all parts of a modern computer, e. g. control unit, memory,
micro sequences, floating point logic (Only the logical unit was not realized).
Konrad Zuse constructed the Z1 in the apartment of his parents, in fact, he was allowed
to use the living room for his construction. In 1936 Zuse quitted his job in airplane
construction to build the Z1. His parents were not enthusiastic, but they did support
him anyway they could.
It was a privately financed machine. Konrad Zuse got money by his parents, his sister
Lieselotte, some students of the Akademischer Verein Motiv and Kurt Pannk, an entrepreneur
The Z1 was in many ways a remarkable machine. Konrad Zuse used thin metal sheets
in order to construct this machine. There were no relays in it. The only one electrical
unit was an electrical engine in order to give the clock frequency of one Hertz to
the machine. The Z1 was freely programmable via a punch tape and a punch tape reader.
There was a clear separation of the punch tape reader, the control unit for supervising
the whole machine and the execution of the instructions, the arithmetic unit, and
the input and output devices.
In 1986 Konrad Zuse decided to rebuilt the Z1. The reason was that the Z1 contained
almost all the important features of a modern computer. In 1986 he constructed thousands
of elements of the Z1 again, because the original Z1 was destroyed by allied airraids
in 1943. In 1989 the rebuilt Z1 was finished and can be visited in the Deutsche Technik
Architecture of the Z1. There are separate units: Control unit, memory, aritmetic
unit with the four basic operations for floating point numbers, the input- and output
devices and the programming unit with the punch tape reader. Not realized was the
logical unit for comparing bits and the arithmetic exception handling.
The Z1 had two registers, each with 22 bits, for the arithmetic operations.