Foundation Computer Studies

Transcription

1 Foundation Computer Studies for Primary Schools Book 3 UBE Edition

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3 Foundation Computer Studies for Primary Schools Book 3 UBE Edition E. O. Adegbeyeni Ph. D. Faculty of Administration University of Lagos Akoka, Lagos

4 Learn Africa Plc Felix Iwerebon House 52, Oba Akran Avenue P.M.B Ikeja, Lagos State Tel. (01) , Fax (01) Website: Area offices and branches Abuja, Akure, Benin, Enugu, Ibadan, Ilorin, Jos, Kano, Owerri, Zaria and representatives throughout Nigeria All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any form or by any means, electronic, mechanical, photocopying or otherwise, without the prior permission of the copyright owner. Learn Africa Plc 2001, 2007 First published 2001 Reprinted 2004 UBE edition 2007 Reprinted 2009, 2010 ISBN

5 Contents Theme 1 Computer awareness 1 Unit 1: History of the computer 3 Unit 2: Classes of computers 6 Theme 2 Computer appreciation 13 Unit 1: Input devices 15 Unit 2: Output devices 20 Unit 3: The system unit 25 Unit 4: Storage devices 29 Unit 5: Diskettes and disk drives 35 Unit 6: Caring for the diskette 39

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7 THEME 1 Computer awareness 1

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9 UNIT ONE History of the computer Many years ago, people used their fingers and toes in counting. They also used stones, pebbles and cowries. Sometimes, seeds of plants like the palm kernel were also used in counting. When many things had to be counted, people could no longer use their fingers and toes, or stones, pebbles, cowries and seeds in counting, and then the computer was invented. The computer was made as a counting machine. The first computer was called the Abacus counting machine. Abacus The first computer was made several years ago by a man called Abacus. It was used for simple additions and subtractions. It is known as the Abacus counting machine. 3

10 Your teacher will show you an Abacus counting machine and how to use it in simple arithmetic. Blaise Pascal A Frenchman called Blaise Pascal made the first adding machine in It was a very big machine. Blaise Pascal s father used this machine in recording taxes collected and spent by the government. Sir Samuel Morland Sir Samuel Morland, an Englishman, invented three calculating machines between 1663 and

11 The first one was used for addition and subtraction of money. The other two were used for more difficult arithmetic. Charles Babbage Charles Babbage, another Englishman, made the first machine that calculates and stores information. His computer was better than an ordinary calculator. It was a very big machine. Charles Babbage is therefore known as the father of the computer. Activities 1 Members of your class should form groups of four. Your teacher will then show you an Abacus counting machine. 2 Each group should make an Abacus counting machine and show the machine in class. 3 Is the Abacus counting machine made by your group different from the one your teacher showed you? What are the differences? 5

12 UNIT TWO Classes of computers Types of computers There are three types of computers. They are 1 the analog computer which is used for measuring things. Examples are the thermometer, car speedometer, rain gauge, blood pressure machine and scale machine

13 2 the digital computer which is used for counting. Examples are the digital wrist watch, calculator and digital thermometer. 3 the hybrid computer which is used for both counting and measurement. An example is the electronic fuel pumping machine. 7

14 8 Activities 1 Give more examples of analog computers. 2 Give more examples of digital computers. 3 Name other hybrid computers that you know. Sizes of computers There are four different sizes of computers. They are 1 microcomputers 2 minicomputers 3 mainframe computers 4 supercomputers Microcomputers are the smallest computers while the supercomputers are the largest. Generations of computers Each new computer was better than the one before it. Each new type of computer is therefore known as a generation of computers. Generations of computers are the stages the computer has passed through before becoming what we now have as computers. There are five stages of development or generations of the computer. Each stage of development is a generation of the computer.

15 First generation computers When computers were first made, they were large and costly. They gave out heat when used. They were also slow in making calculations and could only store very few items of information. They also needed much electricity before they could be used. Second generation computers Soon, the large, costly and slow computers were no longer used by many people. New computers which were cheaper and smaller than the first ones had been made. These were the second generation computers. These new computers stored many more items of information than the earlier computers. They also used less electricity. These second generation computers worked faster than the first generation computers. Third generation computers In the third generation computers, the electric pathways were all joined together as one, inside the computers. This was called an integrated circuit. Electricity therefore moved very fast through the computers. 9

16 The third generation computers were cheaper, smaller and faster than the second generation computers. They also used less electricity and gave out less heat when used. Many people soon began to use the third generation computers. Fourth generation computers The type of computers we use today are the fourth generation computers. The electric pathways are even more completely joined together inside the computers. They are therefore said to have large-scale integrated circuits. The large-scale integrated circuits have made the fourth generation computers better than all the earlier ones. They are smaller, cheaper and store more items of information than the third generation computers. The fourth generation computers also use less electricity and are faster than the third generation computers. The fourth generation computers have made computers to be well known all over the world. 10

17 Fifth generation computers The makers of computers are still working hard to make even better computers. These are the fifth generation computers. They are the next generation of computers. Scientists think that these computers will act like human beings. 11

18 Activities Your teacher will take your class on a visit to offices where computers are used. 1 Write down the names of these offices. 2 What are computers used for in these offices? 3 Which generation of computers is being used in each of the offices? 4 How do you know which generation each computer is? 12

19 THEME 2 Computer appreciation 13

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21 UNIT ONE Input devices The computer system is made up of the hardware and the software components. The hardware components are the things we can see and touch in a computer system. There are three basic parts of the hardware components. These are 1 the input devices; 2 the output devices; and 3 the system unit. In this unit we shall learn about the input devices. Input devices These are used for sending data and information into the computer system. They are also used for telling the computers what we want it to do. The input devices are: 15

22 1 The keyboard The keyboard is used for typing into the computer. It is also used for giving instructions to the computer on what to do. There are three types of keys on the keyboard. They are the alphabetic, numeric and functional keys. The alphabetic keys are the letters of the alphabet, A Z. The numeric keys are the numbers 0 9. Functional keys give instructions to the computer to perform special functions. They are F1 F12 keys. 16

23 2 the mouse This is used to command the computer to carry out certain duties. We use it a lot when drawing on the computer. The mouse is usually placed on a soft material called the mouse pad. 3 The microphone We use the microphone to speak to the computer. What we speak is usually recorded. The 17

24 microphone is also used when we need to talk to persons working on other computers. 4 The joystick This is used for playing computer games. The joystick looks like the gear selector of a car. It has two buttons, which are clicked once or twice to send commands to the computer. The joystick is usually connected to the CPU. 5 The light pen 18

25 When a light pen is connected to the computer, anything written with it on the pad appears on the screen of the monitor. Similarly, one can draw on the pad with the light pen and it appears on the screen. This is then printed on paper using the printer. Activities Look round your school s computer room. 1 How many of the input devices mentioned in this unit can you see? 2 Name them. 3 Which type of keyboard do you have in the room? 4 Which other type of keyboard do you know? 5 What is the difference between the two types of keyboard? 19

26 UNIT TWO Output devices Output devices are parts of the computer system that make the result of processing available to the computer user. They show the information typed into the computer system. These devices also show the information stored in the computer when needed. Output devices are part of the hardware components of the computer system. These output devices are 1 the monitor 20

27 The monitor shows on its screen what is typed into the computer. It also shows what is stored in the computer when needed. There are two types of monitor. The monochrome monitor and the colour monitor. The monochrome monitor shows black and white colours only. The colour monitor shows many colours. It shows all the colours of the rainbow. 21

28 2 the printer Whatever is typed into the computer shows on the monitor. This is put on paper, using the printer. What is stored in the computer shows on the monitor when needed. This is also shown on paper when printed out from the printer. There are many types of printers made by different companies. Some printers print in colours. Other printers show black and white colours only. 22

29 3 speakers Through the speakers, we listen to sound made by the computer system. When computers are used in playing music recorded on CD ROMs, the sound of the music reaches us through the speakers. The sound made by the computer when we play computer games also reaches us through the speakers. Some computer speakers form part of the computer system. They are not seen separately outside like the ones in the photograph above. 23

30 Activities 1 Using one of the computers in your school s computer room, type a letter to your parents. In the letter, thank them for always paying your school fees. 2 Print out this letter on paper. 3 Name all the input devices you used in typing this letter. 4 Name all the output devices you used in typing this letter. 5 Is there any part of the computer you used that is neither an input device nor an output device? 6 Name this part. 24

31 UNIT THREE The system unit The rectangular box of the computer is called the system unit. It is the third part of the hardware components of the computer system. There are two types of system unit. They are: 1 The desktop 25

32 2 The tower The system unit is made up of 1 the central processing unit (CPU), 2 the main memory, and 3 disk drives. The central processing unit (CPU) The CPU enables the computer to think, calculate, count and draw. Without the CPU, the input devices will not be able to give commands to the output devices. The CPU is, therefore, the brain of a computer system. 26

33 The CPU has two parts. The two parts are: 1 the control unit (CU) which controls all the operations of the computer system. 2 the arithmetic and logic unit (ALU) where all arithmetic calculations and logic processes take place. The main memory The main memory of the system unit stores data and instructions for the computer system. Functions of the system unit The system unit 1 stores data, 2 carries out calculations, 3 carries out decisions, and 4 controls the flow of information. Activities 1 Which type of system unit do you have in your school s computer room? 2 Draw the type of system unit that you have in your school. 27

34 28 3 In the presence of your teacher, connect the following parts of the computer together: CPU, monitor, keyboard, mouse, speakers and printer.

35 UNIT FOUR Storage devices Storage devices are parts of the computer system in which we store information. The two kinds of storage devices are the 1. main memory storage devices, and 2. backing storage devices. The main memory storage devices are a) Random Access Memory (RAM) RAM stores data, programming languages and applications software only. This storage is only for some time. It is called a temporary storage. b) Read Only Memory (ROM) ROM stores data and system software only. The storage remains in the computer always. It is called a permanent storage. Backing storage devices provide a permanent storage for large amounts of data and programs. These data and programs can be used 29

36 whenever needed. Backing storage devices are: a) Diskettes b) Hard disk c) Compact disk (CD ROM) d) Magnetic tape e) DVD ROM f) Flash memory Diskettes A diskette stores large amounts of data and information. When this information or data is needed, we quickly get it from the diskette. 30

37 Hard disk The hard disk stores the largest amount of data and information. It is also the fastest and easiest way of storing and getting out stored data and information. Compact disk (CD-ROM) Compact disks are shining, plastic materials that store large amounts of data and information. The data and information stored in a CD-ROM are much larger than that stored in a diskette. 31

38 CD-ROMs are now used for storing music, drawings and video films of very large amounts. They are also used for storing games and educational instructions. DVD ROM 32 DVD

39 DVD means digital versatile disk. A DVD looks like a CD and it can store larger amounts of information. Magnetic tape The magnetic tape is also a backing storage device which stores large amounts of data and information. When needed, we get the data and information stored in a magnetic tape slowly. 33

40 Flash disk The flash disk is very small and highly portable. It stores larger quantity of data when compared to diskettes. It also transfers the data stored in it to the computer at a very high speed. Activity Draw all the backing storage devices on a piece of cardboard and label them. 34

41 UNIT FIVE Diskettes and disk drives The diskette stores data and information typed into the computer. These data and information are used when needed. Diskettes are also used to take information from one computer to the other. There are two types of diskettes: 35

42 diskette 2 5 diskette The 3 diskette is smaller than the 5 diskette. 2 Many more people like to use the diskette than the 5 diskette. The 3 diskette also stores more information than the 5 diskette

43 When we need to know what is stored in the diskette, we put it in the disk drive. The disk drive is on the system unit. Since the two types of diskettes are of different sizes, there are also different disk drives for each type of diskette. 1 4 The 5 disk drive is for 5 diskettes. It is at the upper part of the system unit. 1 2 The 3 disk drive is for 3 diskettes. It is at the lower part of the system unit. The 3 disk drive is 1 4 smaller than the 5 disk drive

44 In addition to the 54 and 32 disk drives, there are also the CD ROM disk drive and the hard disk drives on the system unit. The CD ROM disk can be seen from outside while the hard disk drive is inside the system unit. Activities 1 1 Your teacher will show you how to store information in a diskette and how to use the information when needed. 2 Using one of the computers in your school s computer room, type a letter to your friend telling him about your school s computer 1 room. Store this letter on a 3 diskette. 2 3 Take this diskette to another computer in the computer room. Show the letter on the monitor. 4 Mention the ways by which we can take care of diskettes Why is the 32 disk drive smaller than the 54 disk drive? 6 Draw a diskette box. 1 38

45 UNIT SIX Caring for the diskette In the last unit, you learnt about the diskette. You learnt that a diskette stores a large volume of data and information. If we want to keep our data and other information in good condition, we must take good care of the diskette so that it does not get damaged. To take care of your diskette: 1 Do not play with your diskette like a toy. This will damage the tape inside and this tape 39

46 contains your information. Handle your diskette with care. Handle it like a special object. 2 Do not put your diskette near a hot object or surface. 3 Do not bend your diskette. 4 Keep all diskettes in a dry and safe place. 40

47 Activities 1 How do you keep diskettes in your school? 2 Do you have a diskette box in your school s computer room? 3 Why should you use the diskette box to keep diskettes? 4 How else can you keep diskettes without using the box? 41