History of computer is thousands years old and today’s modern computers are the result of efforts of many people.

Abacus:
History of computer began thousands years ago with the invention of abacus. It is a wooden rack. It has wires on which beads are mounted. It is used to solve calculation problems by following the rules of programming and moving beads. It is believed that China invented it 4000 years ago.




Napier Bones:
John Napier, a mathematician of Scotland introduced an algorithmfor calculation. He also invented Napier Bones which was used by accountants and book-keepers. Slide role was made using his concept of algorithm. This slide role was used till 1970.




Pascal’s Calculator:
In 1642 a French mathematician Blaise Pascal invented Pascal’s calculator. That is also called Pascaline or Arithmetic Machine. His father was a tax accountant and he developed it for helping his father in calculation. It has gears and wheels. It was used for calculation.




Charles Babbage’s Difference Engine:
In 1822, Difference Engine was invented by Charles Babbage. It was a mechanical calculating machine. Charles Babbage is known as the “Father of modern digital computer”. His efforts introduced a number of principles that are basis of modern digital computers.




Hollerith’s Punched Cards:
In 1890, Herman Hollerith invented first electro-mechanical punched card. It was able to read punched information. It was used by IBM and many other manufacturing companies. It was an important invention of that time and widely used for input and output purposes.




First digital computer:
First digital computer was invented by John Eckert and W. Mauchly. It was named as ENIAC (Electronic Numerical Integrator and computer). Size of this computer was very large. It was very slow and used vaccum tubes.




Transistors:
Transistor was invented in 1947 by William Shockley, John Bardeen and Walter Brattain at Bell Labs. It replaced the vaccum tubes. Size of one vaccum tube was equal to 200 transistors. It is faster and cheaper than vaccum tubes.




Integrated Circuits:
Integrated circuit (IC) was introduced in 1958 by Kilby. It replaced the transistors. One integrated circuit consists of thousands of transistors. Integrated circuits reduced the size of computer and made it faster. After the invention of IC use of computer was increased.




Micro Processor:
In 1971, Intel invented the first micro processor that is used in today’s modern computers. It is also called CPU (Central Processing Unit). It is very small in size. It consists of millions of integrated circuits and increased the storage size of computer. It made computer smaller and faster. It revolutionized the world of computer.