Z3

Today it is undisputed that Konrad Zuse's Z3 was the first fully functional, program controlled (freely programmable) computer of the world. The Mark II, the ENIAC and the Colossus followed 1943 and later. The Z3 was presented on May 12, 1941 to an audience of scientists in Berlin. The demonstration was a success.

Who was Konrad Zuse? Professor Dr. Friedrich L. Bauer writes:

Konrad Zuse was the creator of the first full automatic, programm controlled and freely programmable, in binary floating point arithmetic working computer. The Z3 was finished in 1941.

The Z3 as the Z1 contained practically almost all features of modern day computers. The Z3 was built with relays. The Z3 did not have a jump instruction. Konrad Zuse, however, did know the jump instruction, as he implemented it in the micro code for floating point calculations.

No picture of the original Z3 exists. The picture at the right side was taken from a reconstruction made in early 1960 by Zuse KG, Bad Hersfeld. The reconstruction was made for the 1964 Interdata industry fair in Munich. In 1967, it was on display at the Montreal Expo, where it received great attention. It is now owned by the Deutsche Museum in Munich.

The right cupboard contains the relays for the arithmetic unit. Also the relays on
the top of the left cupboard belong to the arithmetic unit. The relays in the left
cupboard with the light color belong to the memory (64 words a 22 bits). On the bottom
of the right cupboard the micro sequencers can be seen, which are the heart of the
control unit of the Z3. The micro sequencers are realized with stepwise relays. They
are used to reduce complicated arithmetic operations to additions or subtractions.
The input-

The block structure of the Z3. There is a separation of the components of the machine,
like the control unit, the memory, the arithmetic unit, and the input-

Guestbook of May 12, 1941.

Presentation of the fully operative Z3.

Presentation of the fully operative Z3.

Drawings of the Z3. In the topmost image only a memory for 32 numbers with a word length of 22 Bits are drawn. The second image shows two cupboards for the memory.

The rebuilt Z3 from 1961.

From left to right: The input output device for decimal floating point numbers. Four digits for the mantissa and 17 digits for the exponent (-8 to +8). The clock frequency generated. The arithmetic exception handling.

Goto the Z4...

Name of Machine

Z3 (May 12, 1941)

Implementation

Relays und stepwise relays.

Frequency

5,3 Hertz

Arithmetic Unit

Floating point, 22 bit, +, -, *, /, square root, arithmetic exception handler.

Average calculation Speed

Addition 0,8 sec. Multiplication 3 sec.

Input

Decimal floating point numbers

Output

Decimal floating point numbers

Word Length

22 bits

Elements

Ca. 2600 relays, 600 in the arithmetic unit, 2000 in the memory incl. The multiplexer for the selection of the memory aadresses.

Memory

64 words with a length of 22 bits.

Power Consumption

Ca. 4000 Watt

Weight

Ca. 1000 KG

Area of Application

Prototyp

Sold

No

Costs

Ca. 50.000 RM

Links

Zuse-Computer (English)

Zuse-Computer (German)

Konrad Zuses Work on a DVD

Comments

The first fully operative automatic, programm controlled and freely programmable, in binary floating point arithmetic working computer. The Z3 was finished in 1941.

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