**CONTENT**

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 computing devices: manual, mechanical and automatic.

**Manual Devices or Mechanical Calculating Tools : Examples are**

- Abacus
- Slide rule

**Mechanical Counting Machines: Examples are**

- John Napier bone
- Blaise Pascal machine
- Gottfried Leibniz machine
- Joseph Jacquard loom
- Charles Babbage analytic machine

**Automatic Devices or Electronic Counting Machines: Examples are**

- Herman Hollerith punch card
- John Von Neumann machine

**EVALUATION**

1. Mention three kinds of computing devices that you know.

2. Give two examples of each above.

**ABACUS**

The first calculating device was probably Abacus. The Babylonians invented it. It is still being used 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. To do simple addition and subtraction you shift the beads from one portion to another.

**SLIDE RULE**

The slide rule is a calculating device that was based on the principles of logarithms. It was first built in England in 1632 and is still in use in the 1960’s by the NASA engineers of Mercury, Gemini, and Apollo programs which led men on the moon.

**NAPIER****’****S BONE**

The need for a better calculating device was felt as time passed. John Napier, a Scottish mathematician in 1617, 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.

**PASCALINE**

The first mechanical calculating machine was invented in 1642, by Blaise Pascal, a French mathematician. Numbers were entered by dialing a series of numbered wheels in this machine. A sequence of wheels transferred the movements to a dial, which showed the result. Though 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 machine that could add, subtract, multiply and divide and called it ** Stepped Reckoner**. Leibnitz was the first to advocate use of binary number system.

**JACQUARD****’****S LOOM**

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

**CHARLES BABBAGE’S DIFFERENCE ENGINE**

In 1822 Charles Babbage proposed a calculating machine known as Difference Engine. It would be able to compute tables of numbers such as logarithm tables but was not finished.

**CHARLES BABBAGE’S ANALYTICAL ENGINE**

In 1833, Babbage designed another machine called Analytical Engine. The machine is as large as a house powered by six steam engines more general purpose in nature and programmable due to the punched card technology of Jacquard.

**MARK I.**

Mark I. invented the world first electro- mechanical computer and was used during World War II by the U.S Navy.

**EVALUATION**

1. List any three computing devices.

2. Mention four scientists who contributed to the development of computers.

**HERMAN HOLLERITH’S MACHINE**

Herman Hollerith invented a machine which worked on electricity for the first time in 1889. One machine was used for recording data and the other one was used for doing calculations of the recording of the recorded data. His machine was capable of reading both numbers and letters.

Hollerith invented the tabulation machine that could read information from punched cards. His machine was used to collate the census data for the United States of America in 1890.

**BURROUGH’S MACHINE**

In 1885, William Seward Burroughs invented this mechanical adding machine. The early Burroughs modes were large machines characterized by having glass panels in the sides, so the mechanism could be seen. Common components of the Burroughs machines are: keypads, lever, registers and printer.

**JOHN VON NEUMANN’S MACHINE:**

John Von Neumann was a Hungarian-born American mathematician developed MINIAC (Mathematics Analyzer, Numerical Integrator and Computer), which at the time was the fastest computer of its kind. The first machine built using Von Neumann’s architecture was the EDVAC.

**PHILIP EMEAGWALI’S COMPUTER:**

Nigerian born Dr. Philip Emeagwali first entered limelight in 1989 when he won the prestigious Gordon Bell Prize for inventing a very fast computer. He programmed a computer that could compute a world record 3.1 billion calculations per second using 65,535 processors to simulate oil reservoirs.

**CONCLUSION**

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

**GENERAL EVALUATION**

(1) List any four pre-computer age to 19^{th} century computing devices.

(2) What are the use(s) of the computing devices you mentioned above?

(3) Give the names of four scientists who contributed to the development of computer.

**Reading Assignment**

Computer Studies for Junior Secondary Education JS1 by HiiT Plc. Page 26 – 29, Chapter 6.

**WEEKEND ASSIGNMENT**

1. Napier’s Bones had ……….. (a) 10 rods (b) 9 rods (c) 11 rods (d) 8 rods

2. Jacquard’s loom was used in the …(a) Mechanical industry (b) Food industry

(c) Weaving industry (d) Electronic industry

3. Who invented the analytical engine? …………. (a) Gottfried Leibnitz (b) Joseph Jacquard (c) Charles Babbage (d) Herman Hollerith

4. Who invented Pascaline? (a) Pascal Joseph (b) Leibnitz Von (c) Blaise Pascal

(d) Charles Babbage

5. …… was the first computing device. (a) Napier’s Bones (b) Punched Card (c) Abacus (d) Slide rule

**THEORY**

1. List any four pre-computer age to 19^{th} century computing devices.

2. Discuss the components and features of the computing devices mentioned above.