# History Of Computer

The history of computers has been divided into three eras. First is the Mechanical era, second is the Electro-Mechanical era and the third is the electronic computer era.

## 1. Mechanical era

#### Abacus:

Abacus is the earliest calculating device. It was developed in China about 3000 years ago. It was made up of a wooden frame with beads sliding on wires.

#### Napier’s Bone:

In 1640 AD, a Scottish mathematician named John Napier. Napier’s bone can multiply simple multiplications with the help of these devices, John Napier was able to invent an algorithm.

#### Slide Rule:

On the basis of Napier’s bone, English mathematician William Oughtered invent a machine for mathematical calculation like addition, subtraction, multiplication with logarithm table The machine is very popular among engineering technical persons.

#### Pascaline:

Around 1642 AD, French Mathematician Blaise Pascal invented the machine that works on gears and wheels for calculations. It could add and subtract very fast and division and multiplication too.

#### Leibniz Calculating Machine or Stepped Reckoner:

Leibniz Calculating machine or Stepped Reckoner was developed after the modification of Pascaline in 1671 AD by Gottfried Wilhelm Leibniz. It can perform all the mathematical calculations at a better speed than the Pascaline.

#### Jacquard Punched Wave(loom):

James Jacquard has invented the machine for the waving industry, that with cardboard and punched hole patterns. Later, the technology is brought to the calculation that can save the result on the punched cards.

#### Charles Babbage:

Around 1822 AD, an English Mathematician Charles Babbage successfully developed a machine called Difference Engine which could solve the algebraic equation quite accurately.

That is a draw-up design for his second machine called Analytical Engine in 1833 AD. In this second machine, he was inspired by Jacquard by using the punched cards for storing instruction. Charles Babbage wanted that computer to work automatically on the instruction that is already given to the computer and it provides the results on the output unit. The Analytical Engine is a prototype of the modern computer. That’s why he was known as the father of computers.

Lady ADA Lovelace is a great follower of Charles Babbage. She worked on Analytical Engine & later, she developed binary number system for the fast operation of computer system and easy to instruct. So, she was known as the first programmer.

## 2. Electro-Mechanical Era:

#### Mark-I:

Mark-I is the electromechanical computer that could automatically accept and perform arithmetic operations, that uses over three thousand electrical switches. It can perform addition, subtraction & multiplication of 23 digits. It took about 0.3 seconds to add two numbers and 4.5 seconds to multiply two numbers. It was developed in 1944 AD by Aiken Howard.

#### John Von Neumann:

The great mathematician John Von Neumann suggested using Binary numbers and the internal storage concept to execute the program automatically. Later, this idea was implemented on a computer system. So, John Von Neumann is known as the father of the stored computers.

#### Atanosoff Berry Computer (ABC)

John Vincent Atanasoff and his assistant Clifford Berry invented ABC in 1938 AD. It uses vacuum tubes for internal logic and capacitors for storage. It could solve certain mathematical equations. It was the first electronic special purpose computer.

## 3. Electronic Computer Era

#### ENIAC (Electronic Numerical Integrated Automatic Calculator):

John Marchly and J.P. Eckert invented ENAIC in 1946 AD. It used 18000 vacuum tubes and a 20×40 square feet area. It could add two numbers in 200 microseconds and multiply in 2000 microseconds.

#### EDSAC (Electronic Delay Storage Automatic Computer):

EDSAC was built in 1949 AD by a group of scientists headed by Mauric Wilkes of Cambridge University. It could add numbers in 1500 microseconds and multiply in 400 microseconds.

#### EDVAC (Electronic Discrete Variable Automatic Computer):

John Maunchly, J.P. Eckert, and John Von Neumann invented EDVAC. It was the first computer based on the stored concepts. It could store both instruction and data in a binary form instead of decimal form.

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