History of computer could be traced back to the effort of man to count large numbers. This process of counting of large numbers generated various systems of numeration like Babylonian system of numeration, Greek system of numeration, Roman system of numeration and Indian system of numeration. Out of these the Indian system of numeration has been accepted universally. It is the basis of modern decimal system of numeration (0, 1, 2, 3, 4, 5, 6, 7, 8, 9). As we know computer does not understand the decimal system and uses binary system of numeration for processing. We will briefly discuss some of the path-breaking inventions in the field of computing devices.

- Calculating Machines: It took generations for early man to build mechanical devices for counting large numbers. The first calculating device called ABACUS, was developed by the Egyptian and Chinese people. The word ABACUS means calculating board. It consists of sticks in horizontal positions on which are inserted sets of pebbles.It has a number of horizontal bars each having ten beads. Horizontal bars represent units, tens, hundreds, etc.
- Napier’s bones:English mathematician John Napier built a mechanical device for the purpose of multiplication in 1617 AD. The device was known as Napier’s bones.
- Slide Rule: English mathematician Edmund Gunter developed the slide rule. This machine could perform operations like addition, subtraction, multiplication, and division. It was widely used in Europe in 16th century.
- Pascal’s Adding and Subtraction Machine: You might have heard the name of Blaise Pascal. He developed a machine at the age of 19 that could add and subtract. The machine consisted of wheels, gears and cylinders.
- Leibniz’s Multiplication and Dividing Machine: The German philosopher and mathematician Gottfried Leibniz build around 1673 a mechanical device that could both multiply and divide.
- Babbage’s Analytical Engine: It was in the year 1823 that a famous English man Charles Babbage built a mechanical machine to do complex mathematical calculations. It was called difference engine. Later he developed a generalpurpose calculating machine called analytical engine. You should know that Charles Babbage is called the Father of computers.
- Mechanical and Electrical Calculator: In the beginning of 19th century the mechanical calculator was developed to perform all sorts of mathematical calculations and it was widely used till 1960. Later the routine part of mechanical calculator was replaced by electric motor. It was called the electrical calculator.
- Modern Electronic Calculator: The electronic calculator used in 1960s was run with electron tubes, which was quite bulky. Later it was replaced with transistors and as a result the size of calculators became too small. The modern electronic calculators can compute all kinds of mathematical computations and mathematical functions. It can also be used to store some data permanently. Some calculators have inbuilt programs to perform some complicated calculations.

### Development of Computer

**1600 A.D.– NAPIER BONES:**

Another counting device is Napier Bones, “John Napier. a Scottish Mathematician, invented it. The “bones” were strips of ivory with numbers written in them. When the bones were arranged properly. the user could read the numbers in adjacent columns to get the answer of a multiplication operation.

**1642 A.D– ADDING MACHINE– BLAISE**

PASCAL– PRANCE

The well known French Scientist and Mathematician, Blaise pascal invented the first machine which could add, carry digits automatically. he was only nineteen years old at that time. His machine was so revolutionary that the principle behind it is still used in most of the machanical counters being used today.

**1692 A.D.– MULTIPLYING MACHINE- COTTFRIED LEIBNITZ- GERMANY**

Gottfried improved upon Pascal’s machine and introduced a mechanism to carry out automatic multiplication of numbers. Leibnita is best known for his work with Sir Isaac Newton in developing a branch of Mathematics, known as Calculus. The calculator in vented by him could add, subtract, multiply and divide accurately. It could even perform square root function, although not always accurately.

**1813 A.D. – DIFFERENCE ENGINE– CHARLES BABBAGE– ENGLAND**

Since early 19th century, Charles Babbage, an Englishman, had been working on the development of a machine, which could perform complex calculations In 1813 A.D. he invented the ‘Difference Engine’ which could perform complex calculations and print them out as well. This machine was a steam powered machine.

**EARLY 1800’S JACQUARD LOOM- JOSEPH MARIE JACQUARD**

In the early nineteenth century, a French weaver Joseph marie Jacquard developed a programmable loom, which used large cards and holes punched in them to control the pattern automatically. The output was a thick rich cloth with repetitive floral or geometric patterns.

Jacquard patterns are still produced to this day. Others adapted the punched cards and used as the primary form of input. They were used till about 20 – 25 years ago.