**History of computers** that means in which time period computing machine are developed.

Table of Contents

## ABACUS:

- ABACUS was invented by Chinese People in 2500 – 3000 BC.
- This is the first calculating machine made up of wooden frame with beads or balls sliding on wire.
- It consists of bars in horizontal positions on which sets of beads are inserted.

## Slide Rule:

- Slide Rule was invented by William Oughtred in 1622.
- First analog device that works on the principle of logarithms.
- It used for Multiplication, Division, Roots, Trigonometry, Logarithm, Exponentiation etc.

## Napier’s Bone:

- Napier’s Bone was Developed by English Mathematician John Napier in 1617 AD.
- Used for Multiplication.
- Also used for dividing and taking square root.

## Pascal’s Calculator:

- Pascal’s Calculator was developed by Blaise Pascal in 1642.
- It is a Mechanical Calculator capable for addition and subtraction.
- In this machine, numbers were entered by dialing a series of numbered wheels each wheel having numbers from 0 to 9.
- It could perform addition and subtraction up to 8 digits.

## Difference Machine:

- Difference Machine was developed by Charles Babbage (called Fathers of computer) in 1821-22.
- It able to perform complex mathematical calculation with 31 digits of precision.
- Used to solve polynomial equations.

## Analytical Engine:

- Analytical Engine was developed by Charles Babbage in 1837.
- General programmable machine.
- Able to Addition, subtraction, multiplication and division through the use of stored program.

**And here we listed others important inventions: **

- Atanasoff Berry Computer (ABC) in 1942: First electronic digital computer
- Hardvard Mark-I in 1944: First automatic electromechanical computer
- ENIAC (
**Electronic Numerical Integrator and Calculator**) in 1946: First general purpose electronic computer. - EDVAC (
**Electronic Discrete Variable Automatic Computer**) : First Store program computer. - EDSAC (
**Electronic Delay Storage Automatic Computer**): First practical stored program electronic computer. - UNIVAC-I (
**Universal Automatic Computer**): First general purpose electronic digital Computer. it is also called the**first commercial computer**.

**Computer Definition, Features, Capabilities & Limitations and Application Are of Computer **