The computer is designed by a professor named Charles Babbage. And analytical engine which was basic framework architecture of computer system was also designed by him. Computers are classified into three generations and each of its generations lasts for a certain period of time also each of them gives us a new computer.

The computer is a mechanical device that is used for calculation and computation, it is much more than that. The computer is a flexible machine to process data and converts it into information. Actually, People of today’s generation has started following a set of procedure to perform various calculation from a digital counting device, which was the first calculating device known as ABACUS.

**ABACUS :**

- The first mechanical calculating device used for calculation is called the abacus. It is used to perform addition and subtraction very easily and in a speedier way. It was first developed by the Egyptians but later on, its final shape is given by the Chinese educationists.
- Abacus is made up of a wooden frame, which contains a rod which is fitted across by the round beads which are sliding on the given rod alternatively. Normally the abacus device is divided into two parts named Heaven and Earth where Heaven is the upper part and Earth is the lower part of it.
- Although, in the abacus, any of its numbers can be represented or calculated by placing each of the beads into their proper place.
- So in short, Abacus is the counting tool or device which is used to calculate and perform various mathematical functions easily which leads to skills of visualization, memory, accuracy, creativity, etc.

**NAPIER’S BONES :**

- It is invented by John Napier in the year 1617.
- It is also a type of operating device which is operated manually for the purpose of calculations of quotients and products of the given numbers.
- It looks like a board game that contains a rim into it. And the various rods are placed inside the rims for the purpose of calculations where the numbers are printed on them.
- It is the better calculating device invented at that time period.

**PASCAL’S Calculator :**

- In the year 1642, a French scientist named Blaise Pascal invented the machine used for addition called Pascal’s calculation.
- It normally represents the position of each digit with the help of gears in it.
- In this, the objective is to perform basic calculation and operations like Addition, subtraction, multiplication, division, etc. and It is made up of metal.
- The calculation of numbers is being done turning the wheels clockwise.

**LEIBNIZ Calculator :**

- In the year 1671, the scientist named Gottfried Leibniz generally modified the Pascal calculator and he designed his own machine for performing various mathematical calculations which are based on multiplication and division as well.
- It is also known as the Leibniz wheel or stepped reckoner.
- It is the type of machine which is used for calculating the engine of a class of mechanical calculators.

**Analytical Engine :**

- Charles Babbage invented the analytical engine in the year 1833. It is created for keeping our data safe.
- It included all of those features which are used in today’s computer language. because of his great invention, Charles Babbage is also known as the father of the computer.
- It is created for general purposes and is also fully program-controlled and also an automatic mechanical digital computer. It was normally programmed with punched cards.
- Although the development of digital computers is rooted in the abacus and early mechanical calculating devices were invented.

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