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Konrad Zuse

• The Person
  • Engineer
  • Artist
  • Innovator
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• Zuse-Computer
  • His aims
  • Die Z1
    • Architecture
    • Operating mode
  • The Z2
  • The Z3
    • Architecture
    • Operating mode
  • The Z4
  • Z22,Z23,Z25&Z64
• After Zuse
• Learning success control
  • Muliple Choice Person
  • Muliple Choice Computers
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Operating mode

The Z3 was a clock-controlled machine. The clock was an electric motor, which pushed a clock roll. This was a drum that rotates 5.3 rounds per second and thus controls the individual relay groups..

The Z3 had the following machine instructions:

Instruction	Description	Time [cycle]
Pr z	Load memory cell z to register R1/R2	1
Ps z	Write R1 to memory cell z	0 - 1
La	Addition: R1 ← R1 + R2	3
Ls	Subtraction: R1 ← R1 - R2	4 – 5
Lm	Multiplication: R1 ← R1 * R2	16
Li	Division: R1 ← R1 / R2	18
Lw	Square root: R1 ← √(R1)	20
Lu	Read decimal number to R1/R2	9 – 41
Ld	Print out R1 as a binary number	9 – 41

The input of data was done either by keyboard or perforated tape, which could contain only 8-bit commands. Numeric characters had to be entered with a keyboard. Furthermore, almost all operations are performed directly from the keyboard, excluded the memory access (Pr and Ps).

Arithmetic unit

In general, the arithmetic unit consists of a unit for calculations with exponents and one unit for calculations with the mantissa. Each arithmetic operation of the Z3 is recycled to the addition of two integers.

At first on addition of two floating-point numbers, the machine calculate the difference of the exponents, the second the appropriate equalization of the mantissa and addition of it.
On subtraction the two's complement of the second mantissa will added with the first mantissa.
For multiplication the two exponents will be added mantissas multiplied by an iterative addition.
Division will subtract the exponents and carry out an iterative subtraction for the division of the mantissa.