# Digital computer

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Replica of the Zuse Z3 , the first functional digital computer

Digital computers (English digit , number, from the Latin digitum , finger) are computers that perform their calculations on the basis of discrete number representations (mostly in binary form). Thus, all of the personal computers in use today are digital computers.

Today most digital computers work on an electronic basis. But others are also possible, for example on a mechanical, pneumatic and optical basis.

The term is often used to differentiate between analog computers that represent numbers analog (non-discrete). A calculated value is represented as electrical voltage or current and the calculation is carried out using suitable circuits. Therefore, analog computers are generally not programmable.

Computer model country Installation Floating point
arithmetic
Binary Electronically Programmable Mighty Turing
Zuse Z3 Germany May 1941 Yes Yes No Yes, using punched tape Yes, without any practical use
Atanasoff-Berry computer United States Summer 1941 No Yes Yes No No
Colossus UK 1943 No Yes Yes Partly, by rewiring No
Mark I. United States 1944 No No No Yes, using punched tape Yes
Zuse Z4 Germany March 1945 Yes Yes No Yes, using punched tape Yes, without any practical use
around 1950 Yes Yes No Yes, using punched tape Yes
ENIAC United States 1946 No No Yes Partly, by rewiring Yes
1948 No No Yes Yes, using the resistor matrix Yes

## Historical background

Finger arithmetic is the oldest calculation method. You can not only count with your fingers, you can also calculate. Very high numerical values ​​can be displayed with the fingers and hands. The first digital calculator is the abacus, which comes in various forms: calculating table, calculating table, counting frame (spherical calculator), calculating cloth. Like finger counting, abacus counting has survived in certain areas to this day. The best-known ball calculators were the Chinese, Japanese and Russian abacus. Other digital computers are relay, tube and transistor computers, as well as mechanical calculating machines such as the Curta.