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Introduction to Computers - Computer Studies Form 1

Introduction

The following are names of electronic devices:

Television

 

Mobile phone


Calculator


Computer


Activity



INTRODUCTION

The following are names of electronic devices

Television

Background

Today, computers have become part and parcel of our day to day activities. It is important that you get acquainted with the knowledge of a computer, how it works and how to use it.





2. Drag each of the graphics into a box containing its appropriate function.


INTRODUCTION TO COMPUTERS

In today's lesson, we shall discuss the meaning of a computer. We shall also learn more about parts and functions of a computer.

Introduction

The following are names of electronic devices.



Lesson Objectives

By the end of the lesson the student is expected to:


1. Understand the major milestones in the development of the modern computers


2. Understand the historical development of electronic computers


Definition of the terms

The activity below shows input, processing and finally output. Input refers to the basic facts and figures to be processed.Processing on the other hand refers to the manipulation of data into meaningful information.Output is the end product of data processing.

Parts of a Computer

A typical computer consists of the following main physical parts:


1. System unit 2. Monitor 3. Keyboard 4. Mouse

Functions of parts of a Computer

System unit

Houses the internal parts of a computer.
Keyboard
Is used to key in data into a computer
Mouse

Is used to control the pointer on the screen Monitor Is also referred to as the screeen or visual display unit (VDU). It displays operations carried out by the computer.
 

Parts of a Computer

A typical computer consists of the following main physical parts:

1. System unit 2. Monitor 3. Keyboard 4. Mouse

Functions of parts of a Computer

System unit

Houses the internal parts of a computer.

Keyboard

Is used to key in data into a computer

Mouse

Is used to control the pointer on the screen

Monitor

Is also referred to as the screen or visual display unit (VDU). It displays operations carried out by the computer.


What is a Computer?

A computer is an electronic device that uses instructions (programs) to accept data as input and processes it to produce information (output).

Introduction





Lesson Objectives

By the end of the lesson you should be able to:


1. Explain the major milestones in the development of the modern computers


2. Outline the historical development of electronic computers

Assessment






Evolution of Computers

Over the years, computers have kept on developing. In this lesson, we shall learn how computers have undergone change by discussing the history and generations.

History of computers

The concepts that form the basis of computer technology have a long history that stretches back over 2000 years.

The Abacus

The abacus, is a calculator. Its first recorded use was Circa 500 B.C. The Chinese used it to add, subtract, multiply, and divide. However, the abacus was not unique to the continent of Asia. Archeological excavations have revealed an Aztec abacus in use around 900 or 1000 A.D.

History of computers

Some of the major inventions are:

In 1614, Scottish mathematician, John Napier, invented logarithm as an aid of calculation.The logarithm of a given number to a given base is the power or exponent to which the base must be raised in order to produce the given number.

John Napier

History of computers

In 1620, English mathematician, William Oughtred, invented the slide rule as an aid of calculation.

William Oughtred

Slide rule

History of computers

In 1642, a Frenchman Blaise Pascal invented a calculating machine(Pascaline) that could add and subtract number.

Blaise Pascal

History of computers

Gottfried von Liebniz


In 1671, a German mathematician, Gottfried von Liebniz invented Liebniz Wheel that could perform the operations add, subtract, multiply and divide.

Gottfried von Liebniz

In 1822, Charles Babbage of England invented the analytical engine that could perform arithmetic operations and store values and answers to calculations. Charles Babbage is referred as the father of modern computers.

Charles Babbage

In 1843, Augusta Ada, countess of Lovelace designed and proposed programs to be used by the analytical engine. She is considered to be the first computer programmer.

Augusta Ada

In 1959, Howard Aiken, developed punched paper tapes, to be used as an input medium. He also invented the first electro-mechanical computer called Mark 1.

Howard Aiken


A person who designs and writes computer programs

In 1938, Claude Shannon demonstrated the similarity between logical circuits and Boolean algebra.

He also formalized information theory which allows precise measurement of information delivered through a communication channel.

Claude Shannon

Computer Electronic Generations

Form the invention of mark 1, rapid advancements in computing industry have been realized and can be categorized into five generations.

First generation computers.(1940s to late 1950s)


1. They used vacuum tubes (thermionic valves) to process data making them unreliable, produced alot of heat, consumed a lot of power, they huge.


2. Drums were used for storage and provided a maximum memory size of 2 Kilobytes.


3.

i


3. The processing speed was 10 kilo instructions per second

Examples included:-ENIAC (Electronic Numerical Integrator and Computer), EDVAC (Electronic Discrete Variable automatic Computer), UNIVAC (Universal Automatic Computer) AND LEO 1 (Lyons Electronic Office)

Second generation computers

1. They were developed between 1958 and 1964.


2. They used transistor technology making them smaller in size than 1st generation.


3. magnetic core memories were used for storage providing a memory size of 32KB


4. The processing speed increased to 300,000 instructions per second

Examples included:-LEO III, IBM 7000 Series and CDC-6600 mainframe, IBM means International Business Machines

Third generation computers


1. They were developed between 1964 and 1970.


2. They used ICs technology and magnetic disks were developed for storage purposes.

Integrated Circuit

Magnetic disk


3. The memory size increased to 2 megabytes, with the speed of up to 5 million instructions per second.


4. The first Minicomputers a multi-user computer designed to meet the needs of a small company or department) were developed in this generation.

Examples included:-ICL 1900 Series and IBM 360 Series.

Fourth generation computers 1971


1. They were developed between 1971 to now.


2. They used LSI (large Scale Integrated circuit) and VLSI (Very large Scale Integrated circuit) technology for main memory and logic circuitry.


3. Microprocessors were introduced during this period (around 1971).


4. Microprocessors enabled the development of very small computers with very high processing speed.


5. Optic disks were developed for storage purposes.

6. The memory size increased to several hundred megabytes, with the speed of up to 50 million instructions per second.

Examples included:-supercomputers

Fifth generation computers


1. These are the computers that are being developed now and in the future.


2. The technology been used include: 3-dimensional circuit design, superconductors and parallel architectures.


3. These generation has seen the merging of telecommunications and computing technology and the development of distributed computing systems.


4. The memory size is in terms of giga and tera bytes and the speed in terms of giga (1 billion bytes ( 109)) and tera (1 trillion bytes ( 1012)) hertz. Hertz is a unit for measuring electrical vibrations. 1 hertz is equivalent ot one cycle per second.

Examples included:-IBM 380 Series and IBM 370 Series.



Computer Electronic Generations

Form the invention of mark 1, rapid advancements in computing industry have been realized and can be categorized into five generations.

First generation computers.(1940s to 1958)


1. They were developed between 1940s and 1958.


2. They used vacuum tubes(thermionic valves) to store and process information.

Computer Electronic Generations

Second generation computers

1.They were developed between 1958 and 1964.
2. They used transistor technology and magnetic core memories.


3.They consumed less power and produced less heat.


4. The computers memory size increased to 32 kilobytes, with a speed of up to 300,000 instructions per second

Examples included:-LEO III, IBM 7000 Series and CDC-6600 mainframe.

( IBM means International Business Machines)

Computer Electronic Generations

Third generation computers


1. They were developed between 1964 and 1970.


2. They used ICs technology and magnetic disks for storage purposes.

Integrated Circuit

Magnetic disk


3. The memory size increased to 2 megabytes, with a speed of up to 5 million instructions per second.


4. The first Minicomputers(a multi-user computer designed to meet the needs of a small company or department) were developed in this generation.

Examples included:-ICL 1900 Series and IBM 360 Series.

Computer Electronic Generations

Fourth generation computers 1971


1. Their development started in 1971 and has continued upto date.


2. They used LSI (large Scale Integrated circuit) and VLSI (Very large Scale Integrated circuit) technology for main memory and logic circuitry.


3. Microprocessors were introduced during this period (around 1971).


4. Microprocessors enabled the development of very small computers with very high processing speed.


5. Optic disks were developed for storage purposes.

6. The memory size increased to several hundred megabytes, with the speed of 50 million instructions per second.

Examples included:-supercomputers


Computer Electronic Generations

Fifth generation computers


1. These are computers currently under development and also for the future.


2. The technology used include: 3-dimensional circuit design, superconductors and parallel architectures.


3. These generation has seen the merging of telecommunications and computing technology and the development of distributed computing systems


4. The memory size is in terms of giga and tera bytes and the speed in terms of giga (1 billion bytes ( 109)) and tera (1 trillion bytes ( 1012)) hertz. Hertz is a unit for measuring electrical vibrations. 1 hertz is equivalent to one cycle per second.

Examples included:-IBM 380 Series and IBM 370 Series.


Introduction

Computers around us come in various forms. The diagrams below shows examples of popular computers in use.

Mobile phone

Calculator

Digital watch


Desktop computer


Camera

Assessment






LESSON OBJECTIVES

By the end of the lesson you are expected to:


1. Classify various types of computers


2. Identify areas where computers are used


Assessment





Classification of Computers

In this lesson, we shall learn about various types of computers, how they are classified and identify areas where computers are used


Classification of computers

There are different types of computers with different operational characteristics.
These computers can be classified into three categories, namely;
1. Classification by physical size and processing power.
2. Classification by functionality
3. Classification by purpose

Classification by Physical size and Processing power

There are four main groups in this category, namely:
1. Supercomputers
2. Microcomputers
3. Minicomputers/mini frames
4. Mainframe computers

Supercomputers

A super computer is a sophisticated, expensive computer designed to execute complex calculations at a maximum speed permitted.

Super computers use multiple processors.

Supercomputers are used for scientific research especially for modeling complex, dynamic systems such as the worlds weather, motion in galaxys way.


Microcomputers


1. They are smaller, less expensive than mainframes.


2. They can be very powerful and capable of running many different applications.


3. Have the capability of being networked to other computers or used as stand-alone units.


4. They are commonly used as personal computers.

Microcomputers are further classified as illustrated. Roll over the mouse pointer to find out more about each microcomputer.

Minicomputers


1. They are smaller less expensive and less powerful than mainframe, and usually perform similar processes to mainframe but on a smaller scale.


2. They can support the same peripheral devices supported by mainframes.


3. They are mainly used network servers in the business industry and in medium scale business.


Mainframe computers


1. They are very large computers with a very high capacity of main storage and very expensive.


2. They can process large amount of data very fast.


3. They can support a large number of terminals.


4. They are used in big companies, banks, insurance companies and government departments.


Classification by purpose

We can classify computers in two main groups according to the purposes of a computer.General purpose computers and special purpose computers.

General purpose computers

These are designed to be used in a variety of application environments as required. They can be adapted to perform a variety of tasks by means of specifically written instructions.

The illustration shows an example of a general purpose computer.

They are the most common type of computers.

Examples are the computers in school laboratories and at homes.

Special purpose computers

Special purpose computers are designed to carry out special processing tasks in one or more application areas, that is they are dedicated to a special task.

Examples are the computers embedded in devices such digital cameras, mobile phones, ovens, calculators and digital watches.

Classification by Functionality

Computers are also classified according to the type of data they can accept and manipulate as:


1. Digital computers


2. Analogue computers

Digital computers

These are Computers that use digits 0 and 1 to represent data, and then use at least partly automatic procedures to perform computations on this information.

Diagrammatical representation of digital data

Analogue computers: Any data to be manipulated by must first be converted to digital form (0 and 1).

Examples are: common computers, digital cameras, digital watches and calculators.

Analogue computers

These are computers which process data which is in continuous state without having to convert data into digital form.

Examples of data which is continuous is; electronic voltage, pressure change, temperature change.

Diagrammatical representation of an analog data

Areas where computers are used

Computers are used in every day life to make it easier and faster to process;data to information. Some important application areas are:

A.Educational Institutions

In schools, computers could be used in different ways.


1. To teach computer studies


2. For keeping students records


3. For administrative and secretarial work


4. As a teaching aid


5. For marking multiple choice examination e.g. KCPE

B. Homes


1. For entertainment e.g. watching movies, playing music and games


2. Communication


C. Hospitals

In hospitals, computers are used for:


1. Keeping records for patients, drugs, personnel


2. Diagnostics purposes eg scanners.


3. Controlling life supporting machines in ICU

D. In Commerce

Used in supermarkets and shops to keep stock and sales records.

E.Industry

In industry, computers are used for controlling industrial processes eg. Automating production processes

F. Banks

In banks computers are used for:


1. Keeping records of financial transactions for customers
2. The Automated Teller Machines (ATM) are used for dispensing and
depositing cash

An ATM Machine


G. Security


CCTV camera

Cameras are used:


1. By the police to detect and monitor criminal activities.


2. To monitor activities of people in sensitive areas, e.g. banks, supermarkets, big hotels, ports;etc.

H. Tele-Communication

Computers are used as telephone communication devices e.g. mobile phones, computerized calling booths.
Below is an example of a mobile phone.




Objectives

By the end of the lesson you are expected to:


1. Define a computer laboratory


2. State the rules, safety precaution and practices in a computer laboratory





Computer Laboratory

In this lesson, we shall define the computer laboratory, and learn how the laboratory is set up. We shall also look at rules and safety precautions to be observed while working in the laboratory.

What is a Computer Laboratory?

It is a specially prepared room to facilitate installation of computers and to provide a safe conducive environment for teaching and learning using computers.

a typical computer laboratory


Setting up a Computer Laboratory

The following are some of the factors to consider when setting up a computer laboratory:


1. Security of the computers


2. Availability of stable Electric Power


3. Number of computers to be installed


4. Number of users to be accommodated at ago.


Rules and Safety Precautions

A laboratory without rules and regulations is like a public road without traffic rules.Rules and regulations ensure safety and security for the users and machines. They minimise damage to the machines and ensure health of the user, bringing about good conducive learning and working environment.

Rules and regulations

Whenever working in the computer laboratory,always shut down the computer using the correct procedure to minimise damage. Do not allow unauthorised persons in the laboratory .Do not carry any foodstuffs or fluids into the computer laboratory. The may spill and get into the computer parts and damage them. Avoid unnecessary movements that may lead to accidents.Do not open computer parts without permission


Safety Precautions in the Laboratory

Computers are expensive and costly to maintain. They are also delicate and therefore require good care in order to last long. Some of the safety precautions to be observed are:


1. They must be covered after use to avoid dust settling on the components


2. The laboratory should be locked and fitted with burglar proof grill to prevent unauthorised access


3. The cables should be properly insulated and laid well to avoid exposing users to electric shock and short circuit.


4. The laboratory should have fire extinguisherss in case of outbreak of fires


5. There should be stable power supply for the computers i.e use of Uninterruptible Power Supply (refer to UPS)

6. Storage media should be scanned before using. This will minimise the spread of computer viruses.


UNINTERRUPTED POWER SUPPLY

Safety Precautions for the users

The health of the computer user is also as important as the safety of computers.It is therefore important to observe practice in order to be more productive.Some of these precaution are:

1. We should have standard furniture to ensure comfort and avoid strain.


2. The laboratory should have a good lighting system to avoid straining of eyes


3. There should be good ventilation to allow fresh air into the room both for the user and to cool the computers


4. Computer monitors must be fitted with antiglare devices to aid in filtering light to care for eyes.

Objectives

By the end of the lesson you are expected to:


1. Start, restart and shut down a computer


2. Use the mouse and the keyboard effectively


Assessment



HANDS ON SKILLS

In this lesson, we shall learn various hands on skills including the mouse, mouse terminologies, start-up, cold boot, warm boot, shutting down and keyboard skills.

Mouse skills

A computer mouse is a hand held input device which is used to select commands on the screen. It controls the movement of the pointer (cursor) on the screen and the buttons are pressed or clicked to perform specific tasks. In this lesson it is assumed you are Right handed. The correct way to hold a mouse is as seen below.


The mouse pointer is the symbol that indicates the position of mouse on the monitor.

The wrong way to hold a mouse is as shown below.


Is the symbol that indicate the position of mouse on the monitor.

Mouse terminologies

Mouse terminologies explains various mouse techniques.Selecting an item involves Clicking on the item.While selecting a text involves selecting an item then hold down the mouse button and drag over the text.This process is done to select an item.Double clicking is used to initiate an action, such as opening a file.


Mouse terminologies

Right clicking is pressing and releasing the right button. This process is done to display command menus that are specific to the item selected.


Mouse terminologies

Drag and drop is a technique used for moving items from one location to another on the screen. This is done by clicking on the item without releasing then you slide the mouse to a new location and then release.


Starting up a computer

To ensure the safety of a computer system, the following steps should be followed when starting up:


1. Ensure that all the cables are properly connected. 2. Switch on main power supply. 3. Switch on the power backup (UPS) 4. Swich on the monitor. 5. Switch on the system unit. 6. Wait for the computer to finish the starting up process.


The standard power switch with most electronic devices is represented in the diagram below.


The starting up process is also referred to as booting.

During booting, the computer checks all the basic parts to determine whether they are working properly. This process is referred as POST (Power on self test).

Booting is controlled by a special program called BIOS (Basic input output system).

Booting can be classified into two:


1.Cold boot


2.Warm boot


Shutting down

This is a process where a computer which is on is Turned Off.The procedure to Turn off when using Windows 2000 and XP is:


1. Click on the start button


2. Click Turn Off Computer button


3. Select Turn Off button and click.

NB: It is possible to shut down the computer using short cuts e.g. alt+F4

The correct shut down procedure should always be followed to avoid damage to the computer.


Keyboard

A keyboard is an input device used for entering data such as text ,numbers and symbols by tapping the keys ( keying in)

The arrangement of keys (text, numbers and symbols) on the computer's keyboard is known as keyboard layout.


Keyboard Skills


1. Sit upright


2. Place the material to be typed on your left.


3. Place both hands on the keyboards Home Keys


4. Use all the ten fingers to start typing slowly at first.


5. Speed will be improved gradually with a lot of practice.

Special keys

These are keys used in conjunction with other keys to issue commands that are specific to the application program being used.

They include the:




Cursor movement and editing keys

Cursor movement keys are used for moving the cursor around the text. They include:Roll the mouse pointer over the named key to observe its function.






Editing Keys are used for making corrections in a text. They include:




Keyboard layout

Keys on the keyboard can be categorised into five groups namely:-


1. Alphanumeric keys


2. Function keys


3. Cursor movement and editing keys


4. Special PC operation keys


5. Numeric keypad

Numeric Key Pad

These are keys found on the extreme right of the keyboard. They are used for entering numeric data and performing calculations when the Num Lock key is turned on. They consist of 0 to 9, mathematical symbols addition(+), subtraction(-), multiplication(*) and division(/).

They can also be used for cursor movement and editing keys when the Num Lock key is turned off.


Alphanumeric Keys

These are keys with letters A to Z, numbers 0 to 9, symbols (@, #, %, &, *, <, >,/, punctuation marks etc used for typing in text and other data.

Other typing of keys include:


1. Caps Lock key- used for changing between lower case and upper case


2. Enter (Return) key- used to execute commands e.g. to start a new line in word processing programs


3. Space bar- creates a space between words when typing


4. Backspace - deletes characters and spaces to the left of the insertion point


5. Tab key- moves the insertion point at set intervals on the same line

 

Function keys

These are keys labeled F1, F2, F3 upto F12. They are used to issue commands specific to an application program being used. For example in windows operating system,


1. F1 is used for help


2. F2 is for editing file names


3. F5 is for refreshing


4. F8 is for choosing OS while rebooting

Different keys can be used for different functions depending on the application being used.


Cold boot

Cold booting is when a computer that was off is started.The process of cold booting is used to start up your computer.


NB:
Next time you start the computer be keen and note the process. You will see the keyboard lights go on as an indication of POST.

Warning:

Avoid frequent cold booting. This causes the electronic parts to contract and expand rapidly thereby damaging them. 

Warm booting

Warm booting is the process where a computer that is on is forced to restart by use of the restart button or restart option in the Turn Off option (Window 2000 and later versions).

Warm booting is used in case the computer hangs.


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