# History of Computer

History of Computers Generation

The word ‘computer’ has a very interesting origin. It was first used in the 16th century for a person who used to compute, i.e. do calculations. The word was used in the same sense as a noun until the 20th century. Women were hired as human computers to carry out all forms of calculations and computations. By the last part of the 19th century, the word was also used to describe machines that did calculations. The modern-day use of the word is generally to describe programmable digital devices that run on electricity.

Early Development of Computer: Mechanical Calculating Device

﻿Abacus:  It is the first counting device, developed by Chinese and Egyptians, 2500 years ago. It performs mathematical concepts and arithmetical operations. It is a rectangular box, divided into two parts by mid bar, the upper part is called heaven, consists of two beads and each bead equal to value 5 and the lower part is called earth, which consists of five beads and each bead equal to value 1. While calculating, beads are brought near to the mid bar.

﻿Napier's Bones: Another interesting invention is Napier's bones, a cleaver multiplication tool invented in 1614 by mathematical John Napier of Scotland. The bones are set of vertical rectangular rods, each one divided into 10 squares. John Napier is also the inventor of logarithms, a concept used to change multiplication into addiction. Napier's bones were very successful and were widely used in Europe until mid 1960s. It is mainly used for multiplication tables.

Slide Rule: The Slide Rule is an analog device for performing mathematical computations. The first slide rule was created by a British mathematician, William Oughtred in 1620. His device was based on the log arithmetic scale created by British astronomer, Edmund Gunter in 1620, Gunter's work, in turn, was based on the principle of logarithm set forth by Scottish mathematician John Napier in 1614. A simple slide rule consists of two graduated scales, one of which slips upon the other. The scaled are devised in such a way that suitable alignment of one scale against the other makes it possible to obtain products, quotients or their function by inspection.

Pascaline:  Blaise Pascal had a father who was an overworked and harassed tax commissioner. The young Pascal developed a mechanical calculator to help him with his work. Pascal started to build it in 1632 when he was 19 and three years later he had developed a machine called Pascaline. In this machine, numbers were entered by dialing a series of number wheels, and a series of toothed wheels. Each wheel is printed with numbers from 0 to 9. When the first wheel made a completed turn from 0 to 9, it automatically caused the second wheel to advance to the next number and so on. It could add and subtract by the movement of wheels. The calculating capacity of Pascaline was 9, 99, 99, and 999. It could not be used for division and multiplication.

Difference Engine:  Charles Babbage developed a different engine in 1823. Difference engine was the first programmable machine ever made. This device was used for solving differential equations. This device has different sections for input, output, and storage media. The machine can give results and process it. There are different parts of the engine are :

• Input

• Mill (processing)

• Memory

• Output (Results)

Dr. Herman Hollerith:  The first person to use punched card practically is Dr. Herman Hollerith. Using the punched card, he developed the tabulating machine or census machine which proved to be very efficient. In 1896, he also established Tabulating Machine Company (TMC). He later founded the International Business Machine Company by merging it with other companies in 1933.

Lady Augusta Ada Lovelace:  Lady Ada suggested using binary numbers instead of decimal number in Analytical Engine. Lady Ada also wrote a program to be used in Analytical Engine. She is also known as the " First Programmer" in the history of computer science because this was the first program ever written.

﻿Stepped  Reckoner:  Stepped  Reckoner is a calculating device developed by Gottfried Wilhelm Von Leibnitz, It was designed in 1671 and built around 1673 and completed in 1694. It was modified to produce higher efficiency and was based on pascal's principle. The stepped Reckoner could multiply, add, subtract and even find square roots.