**EARLY MECHANICAL COUNTING/CALCULATING DEVICES**

- Abacus
- Slide rule

**EARLY ELECTRO-MECHANICAL COUNTING DEVICES**

- John Napier bone
- Blaize Pascal machine
- Gottfried Leitbnitz machine
- Joseph Jacquard Loom
- Charles Babbage analytical machine

**EARLY ELECTRONIC COUNTING DEVICES**

- Herman Hollerith punch card
- John Von Neumann machine

Man has put in every effort to have better methods of calculations. As a result of man’s search for fast and accurate calculating devices, the computer was developed. Essentially, there are three kinds of calculating devices: manual, mechanical and automatic.

**ABACUS**

The first calculating device was probably Abacus. The Chinese invented it. It is still in use in some countries because of its simple operation. It is made up of a frame divided into two parts by a horizontal bar and vertical threads. Each thread contains some beads. It was used to calculate simple addition and subtraction.

** **

**NAPIER’S BONE**

The need for a better calculating device was felt as time passed. John Napier, a Scottish mathematician, invented a set of eleven rods, with four sides each which was used as a multiplication tool. These rods were made from bones and this was the reason why they were called Napier Bones. The rods had numbers marked in such a way that, by placing them side by side, products and quotients of large numbers can be obtained.

** **

**EVALUATION**

- Explain types of early counting devices.
- How does Abacus and Napier’s function.

**PASCALINE**

The first mechanical calculating machine was invented in 1642, by Blaize Pascal, a French mathematician. Numbers were entered by dialling a series of numbered wheels in this machine. A sequence of wheels transferred the movements to a dial, which showed the result.

Through addition and subtraction were performed the normal way, the device could perform division by repeated subtraction and multiplication by repeated addition.

** **

**LEIBNITZ CALCULATING MACHINE**

Gottfried Wilhelm Von Leibnitz invented a computer that was built in 1694. It could add and after changing some things around, it could multiply. Leibnitz invented a special stepped gear mechanism for introducing the added digits and this is still being used.

** **

**JACQUARD’S LOOM**

Jacquard’s loom was one of the first machines that were run by a program. Joseph Jacquard changed the weaving industry by creating a loom that controlled the raising of the thread through punched cards. Jacquard’s loom used lines of holes on a card to represent the weaving pattern.

** **

**PUNCHED CARD**

During the years1920 and 1930, the punched card system developed steadily. A standard card was divided into 80 columns and 12 rows. Only one character could be represented in the 80 columns, thus providing a maximum of 80 characters per card. Punching one, two or three holes in any one column represented a character. Holes were punched into a blank card by a punch machine whose keyboard resembled that of a typewriter.

** **

**CONCLUSION**

We have learnt about the various calculating devices and the various ways they perform their operations. We learnt also that Abacus was the first calculating devices.

**NUMBER SYSTEM (REVISION)**

To effectively use the computer, it is therefore necessary to know how data is represented and communicatedto it. There are different ways of representing data in the number system, namely:

- Decimal System
- Binary System
- Octal System
- Hexadecimal Number System.

**GENERAL EVALUATION**

- How does Abacus and Jacquard’s loom function?
- What type of operation can Pascaline perform?
- Explain the four number system.
- List any four early counting devices.

** **

**WEEKEND ASSIGNMENT**

- Napier’s Bones had ……..A. 9 rods 11 rods C. 10 rods D. 12 rods
- Jacquard’s loom was used in the ……A. mechanical industry weaving industry C. food industry D. all of the above
- ……. was the first calculating device. A. Napier’s Bones Punched card C. Abacus D. Slide rule
- The octal number system has a radix of ……. 7 B. 10 C. 16 D. 8
- The Decimal Number is in Base ……A. 2 8 C. 10 D. 16

**THEORY**

- Describe a standard Punch Card.
- Explain Decimal Number system.

See also

MAINTENANCE OF COMPUTER HARDWARE