Introduction to ICT

Definition of Terms
Information Communications Technology (ICT)
ICT stands for Information and Communication Technologies. It is closely related to Information
Technology.

1. Information
Data that has been processed, organized/structured/presented in a given context so as to make it useful. Data
is given meaning by a rational connection. It basically involves the understanding of relations.

2. Communication
The process of imparting, or interchange of thoughts, opinions or information by speech, writing or signs.
Simply put, it’s the act of transferring information from one place to another. Telecommunication is
communication over a distance. This is achieved by use of electrical signals or electromagnetic waves.

Tools used in telecommunication include:

• Telegraph • TV • Fiber Optics
• Telephone • Internet/Networks • Satellite
• Radio • Microwaves

3. Technology
It is the collection of techniques, skills, methods, and processes used in the production of goods or services
or in the accomplishment of som objectives. Technology can be the knowledge of techniques, processes, and
the like. This knowledge can be used for practical purposes such as being embedded in machines to allow
for operation without detailed knowledge of their workings.

ICT is thus the integration of telecommunication and computer technologies for the purpose of
communication. It is concerned with all digital technologies that aid in the storage, retrieval, manipulation,
transmission and receipt of data.

Functions of ICT
These depend on the environment ICT is used.
In a school scenario, ICT may be used in:
• Learning: - Word processing.
• Communication: - email
• Management: - Management information Systems e.g. Library Management, Financial applications
etc.)
Introduction to Computers

Definitions

Computer
A Computer is an electronic device that processes data to give information under the control of special
instructions called programs.

A computer automatically accepts data & instructions as input from an Input device, stores them temporarily
in its memory, then processes that data according to the instructions given, and finally transfers the
processed data (information) to an storage or output device.

Explanations
 A computer is described as an electronic device because; it is made up of electronic components and uses
electric energy (such as electricity) to operate.

 A computer has an internal memory, which stores data & instructions temporarily awaiting processing,
and even holds the intermediate result (information) before it is communicated to the recipients through
the Output devices.

 It works on the data using the instructions issued, means that, the computer cannot do any useful job on
its own. It can only work as per the set of instructions issued.

A computer will accept data in one form and produce it in another form. The data is normally held within
the computer as it is being processed.

Program
A computer program is a set of related instructions written in a certain programming language and is used to
make the computer perform a specific task (or, to direct the computer on what to do).

Data
Data is a collection of raw facts, figures or instructions that do not have much meaning to the user. Data
may be in form of numbers, alphabets/letters or symbols, and can be processed to produce information.

Types of Data
There are two types/forms of data:

a. Digital (Discrete) Data

Digital data is discrete in nature. It must be represented in form of numbers, alphabets or symbols for it to
be processed by a computer. Digital data is obtained by counting. E.g. 1, 2, 3 …

b. Analogue (continuous) Data

Analogue data is continuous in nature. It must be represented in physical nature in order to be processed by
the computer.

Analogue data is obtained by measurement. E.g. Pressure, Temperature, Humidity, Lengths or currents, etc
The output is in form of smooth graphs from which the data can be read.

Data Processing
It is the process of collecting all items of data together and converting/transforming them into information.
Processing refers to the way the data is manipulated (or handled) to turn it into information.

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Data processing activities include:
• Collection (Measuring, Recording, and Comparing)
• Conversion (Coding, Classifying, and Transforming)
• Storage (Storage and Retrieval)
• Communication & Reproduction

The processing of the data usually results in some meaningful information being produced.

Information
Information is the data which has been refined, summarized & manipulated in a particular way, or into a
more meaningful form for decision-making.

The information must be accurate, timely, complete and relevant.

Comparison between Data and Information

Data Information
1. Unprocessed (raw) facts or figures. 1. It is the end-product of data processing
(processed data)
2. Not arranged. 2. Arranged into a meaningful format.
3. Does not have much meaning to the user. 3. More meaningful to the user.
4. Cannot be used for decision-making. 4. Can be used to make decisions.

Characteristics / Features of a Computer

Before 20th century, most information was processed manually or by use of simple machines. Today,
millions of people are using computers in offices and at home to produce and store all types of information

The following are some of the attributes that make computers widely accepted & used in the day-to-day
activities in our society:

1. Speed
Computers operate at very high speeds, and can perform very many functions within a very short time. They
can perform a much-complicated task much faster than a human being.

The speed of a computer is measured in Fractions of seconds.

a. Millisecond - a thousandth of a second (10-3)
b. Microsecond - a millionth of a second (10-6)
c. Nanosecond - a thousand millionth of a second (10-9)
d. Picosecond - a million millionth of a second (10-12)

The speed of a computer is usually linked to the technology used to build it.

2. Accuracy
Unlike human beings, computers are very accurate, i.e., they never make mistakes.

A computer can work for very long periods without going wrong. However, when an error occurs the
computer has a number of in-built, self-checking features in their electronic components that can detect &
correct such errors.

Usually errors are committed by the users entering the data to the computer, thus the saying Garbage in
Garbage Out (GIGO). This means that, if you enter incorrect data into the computer and have it processed,
the computer will give you misleading information.

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 3. Reliability
The computer can be relied upon to produce the correct answer if it is given the correct instructions &
supplied with the correct data.

Therefore, if you want to add two numbers, but by mistake, give the computer a “Multiply” instruction, the
computer will not know that you intended to “ADD”; it will multiply the numbers supplied.

Similarly, if you give it the ADD instruction, but make a mistake and enter an incorrect data; let say, 14 &
ss83 instead of 14 & 38; then the computer will produce the “wrong” answer 97 instead of 52. However,
note that, 97 is ‘correct’ based on the data supplied.

Therefore, the output produced by a computer is only as reliable as the instructions used & the data supplied.

4. Consistency
Computers are usually consistent. This means that, given the same data & the same instructions, they will
produce the same answer every time that particular process is repeated.

5. Storage
A computer is capable of storing large amounts of data or instructions in a very small space. A computer can
store data & instructions for later use, and it can produce/ retrieve this data when required so that the user
can make use of it.

Data stored in a computer can be protected from unauthorized individuals through the use of passwords.

6. Diligence
Unlike human beings, a computer can work continuously without getting tired or bored. Even if it has to do
a million calculations, it will do the last one with the same speed and accuracy as the first one.

7. Automation
A computer is an automatic device. This is because, once given the instructions, it is guided by these
instructions and can carry on its job automatically until it is complete. It can also perform a variety of jobs as
long as there is a well-defined procedure.

8. Versatile
A computer can be used in different places to perform a large number of different jobs depending on the
instructions fed to it.

9. Imposition of a formal approach to working methods

Because a computer can only work with a strict set of instructions, it identifies and imposes rigid rules for
dealing with the data it is given to process.

Parts of a Computer
A computer is made up of a collection of different components that are interconnected together in order to
work as a single entity.

A Computer consists of the following parts/devices: -

• Hardware: - Physical/tangible parts. Can be felt.
o The System Unit.
o Input devices.
o Output devices.
o Storage devices.

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 • Software: - Programs/instructions. Preinstalled or acquired by users.
o System Software: - consists of the programs that control the operations of a computer and
its devices.
▪ Operating System (OS): - coordinates all activities among hardware devices and
contains instructions that allow you to run application software. You interact with
software through its user interface.
▪ Utility Programs: - performs specific tasks, usually related to managing a
computer, its devices, or its programs.
o Application Software: - consists of programs that perform specific tasks for users. Popular
application software includes word processing software, spreadsheet software, database
software, and presentation graphics software.
• Liveware/ Organoware: - Computer Users
o Novice Users: People who have not used the computer before or have just started using the
computer.
o Intermediate Users: People who know the basics of using the computer. They may use a
limited number of applications. e.g. secretaries, clerks, students etc.
o Expert Users: People who are very experienced in using the computers e.g. IT technicians,
programmers, hackers etc.

History of Computing
Before 1900, most data processing was done manually using simple tools like stones & sticks to count and
keep records.

Around 2000 years ago, Asian merchants came up with a special calculating tool called Abacus that could
be used to calculate large figures.

An Abacus is made up of a rectangular frame and a crossbar at the middle. It is fitted with wires or strings
running across from the frame to the crossbar.

How to represent a number using an Abacus

Each bead in the lower row has a value of 1, while each bead in the upper row has a value of 5. To represent
a number, the bead is moved to the crossbar. Those beads away from the crossbar represent zeros.

The Figure below represents the number 6908 (Six thousand nine hundred and eight).

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After Abacus, the first machine that is usually regarded as the forerunner of modern computers was named
the Analytical Engine, and was developed by an English mathematician called Charles Babbage.
Other technical advancements made in this era also include: Napier Bones & Logarithm Tables by John
Napier; Odometer (Speedometer); Mechanical Calculator Blaise Pascal (1641); Punch Card Herman
Hollerith (1880) and Electrical Machines e.g. Enigma.

In 1939, Professor Howard Aken of Horrard University designed the first computer-like machine named
Mark 1.

Since then, a series of advancements in electronics has occurred. With each breakthrough, the computers
based on the older form of electronics have been replaced by a new “generation” of computers based on the
newer form of electronics.

Computer Generations
A Computer generation is a grouped summary of the gradual developments in the computer technology.
The historical events are not considered in terms of individual years, but are classified in durations (a period
of more than a year).

1ST Generation computers (1946 – 1956).

i. The 1st generation of computers used thousands of electronic gadgets called Vacuum tubes or
Thermionic valves to store & process information.

a.
1. Vacuum tube
ii. The tubes consumed a lot power, and generated a lot of heat during processing due to overheating.
iii. The computers constantly broke down due to the excessive heat generated, hence were short-lived,
and were not very reliable.
iv. They also used Magnetic drum memories.
v. Cards were used to enter data into the computers.
vi. Their internal memory capacity was limited. The maximum memory size was approx. 2 KB (2,000
bytes).
vii. The computers used big physical devices in their circuitry; hence they were very large in size, i.e. the
computer could occupy several office blocks. For example, ENIAC occupied an area of about
150m2 - the size of an average 3-bedroom house.
viii. They were very slow - their speed was measured in Milliseconds. E.g., ENIAC (the earliest
electronic computer) could perform 5,000 additions per second & 300 multiplications per second.
ix. The computers were very costly - they costed millions of dollars.

Examples of 1ST Generation computers:

• ENIAC (Electronic Numerical Integrator And Calculator) built in 1946 for use in World War II. It
contained 18,000 Vacuum tubes.
• EDVAC (Electronic Discrete Variable Automatic Computer) developed in 1945 by Dr. John Von
Neumann. It was the first computer that used instructions stored in memory.
• UNIVAC (UNIVersal Automatic Computer).
• IBM 650.
• LEO (Lyon’s Electronic Office).

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2Nd Generation computers (1957 – 1963).
i. The 2nd generation computers used tiny, solid-state electronic devices called Transistors. The
transistors were relatively smaller, more stable & reliable than vacuum tubes.

1. Transistor

ii. The computers consumed less power, produced less heat, were much faster, and more reliable than
those made with vacuum tubes.
iii. They used Magnetic core memories.
iv. RAM Memory size expanded to 32 KB.
v. Their operation speed increased to between 200,000 – 300,000 instructions per second. Their speeds
were measured in Microseconds. E.g., a computer could perform 1 million additions per second,
which was comparatively higher than that of the 1st generation computers.
vi. The computers were smaller in size & therefore, occupied less space compared to the 1st G
computers.
vii. They were less costly than the 1st G computers.

Examples of 2nd Generation computers:

• NCR 501, IBM 300, IBM 1401, IBM 7070, IBM 7094 Series & CDC-6600 Mainframe computers.
• ATLAS LEO Mark III.
• UNIVAC 1107.
• HONEYWELL 200.

3RD Generation computers (1964 – 1979).

i. Used electronic devices called Integrated Circuits (ICs), which were made by combining thousands
of transistors & diodes together on a semiconductor called a Silicon chip.

Integrated circuit

ii. The processing speed increased to 5 Million instructions per second (5 MIPS).
iii. The storage capacity of the computers (i.e., the RAM memory sizes) expanded to 2 MB.
iv. They were smaller in size compared to 2nd generation computers.
v. The computers used a wide range of peripheral devices.
vi. The computers could support more than user at the same time. They were also able to support
remote communication facilities.
vii. Magnetic disks were developed for storage purposes.
viii. The 1st microcomputer was produced during this period (1974).

Examples of 3rd Generation computers:

• IBM 360, 370;
• ICL 1900 Series;
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 • 8-bit Microcomputers & PDP-11 Mainframe computers.
Advantages of ICs
• Very small
• Lesser weight
• Reduced cost
• High reliability. Few connections, less temperature rise and low rate of failure.
• Low power requirement.
• Easy Replacement.

General Uses
• Amplifiers (Power, Signal, Operational, RF & IF and Microwave)
• Voltage comparators
• Multipliers
• Radio receivers
• Voltage regulators.

Use in Computers
• Flip flops • Memory chips
• Logicgates • Clock chips
• Timers • Microprocessors
• Counters • Microcontrollers
• Multiplexers • Temperature sensors
• Calculator chips

4TH Generation computers (1979 – 1989).

i. The 4th generation computers used Large Scale Integrated (LSI) circuits & Very Large Scale
Integrated (VLSI) circuits. These circuits were made by compressing more tiny circuits and
transistors into even smaller space of the silicon chip.

a.
i. Very Large integrated circuit

ii. The computers were small, and very fast. Their processing speeds increased to 50 Million
instructions per second.
iii. Had large storage capacity, i.e., their memory sizes expanded to several hundred Megabytes.
iv. Memories used included Magnetic disks, Bubble memories & Optical disks.

Examples of 4th Generation computers:

• IBM 308 and 4300;

• Amdahl 580
• Honeywell DPS-88
• Burroughs 7700, and the 16-bit & 32-bit microcomputers. The first microcomputer was called Apple
II.

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 5TH Generation computers (1990 – Present).
i. In this generation fall today’s computers.
ii. The technologies used are Parallel architectures, 3-Dimensional circuit design & super conducting
materials.
iii. These technologies have led to the development of computers referred to as Supercomputers, which
are very powerful, and have very high processing speeds. Their speeds are measured in
Nanoseconds & Picoseconds.
iv. They are able to perform parallel (or multi-processing) whereby a single task is split among a
number of processors.
v. The memory sizes range between 1 Gigabyte & 1 Terabyte.
vi. The computers are designed using VLSI and the Microchip technology that has given rise to the
smaller computers, known as Microcomputers used today.

The computers have special instruction sets that allow them to support complex programs that mimic human
intelligence often referred to as Artificial Intelligence. Such programs can help managers to make decisions
and also provide critical expert services to users instead of relying on human professionals.

Classification of Computers
Computers can be classified according to the following factors:
• Physical size & processing power;
• Purpose for which they are designed;
• Functionality (Method/Mode of operation)

1. Classification According to Physical Size

Computers can be classified into 5 main groups according to their size as:
• Supercomputers.
• Mainframe computers.
• Minicomputers.
• Microcomputers.
• Portable computers (Laptops, Notebooks & Palmtops).

a. Supercomputers
i. Supercomputers are the fastest, largest, most expensive & also the most powerful computers
available.
ii. They are very fast in processing. They can perform many complex calculations in a fraction of a
second.
iii. Most Supercomputers use multiple processors. In this case, a single task is split among the
processors for faster execution. However, all the processors are controlled by a single central
processor.
iv. Supercomputers generate a lot of heat, & therefore require special cooling systems. Sometimes, the
whole CPU is deeped in a tank containing liquid Fluorocarbon to provide cooling.
v. Supercomputers are very large & heavy, and are usually kept under special environmental
conditions (i.e., in a special room).
vi. They are operated by computer specialists. A Supercomputer can be operated by over 500 users at
the same time.

Areas where supercomputers are used:

Supercomputers are mainly used for complex scientific applications that involve many calculations &
require a lot of computational power. Some of the applications that use supercomputers include;
i. Weather forecasting.
ii. Petroleum research.
iii. Defence and weapon analysis.
iv. Aerodynamic design and simulation.
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 Note. These tasks use large amounts of data, which need to be manipulated within a very short time.
Examples of Supercomputers
i. CRAY T3D
ii. NEC-500

b. Mainframe Computers
i. Mainframes are less powerful & less expensive than supercomputers.
ii. They are big in size but smaller compared to Supercomputers.
iii. Powerful computers with very high capacities of Main storage. They also have a large backing
storage capacity.
iv. Have a very high processing speed, i.e., can process large amounts of data very quickly.
v. They can support a large number of peripherals of different types (can support between 5–300
terminals).
vi. They can handle hundreds of users at the same time, e.g., they can be operated by 200 users at a
time.
vii. Mainframe computers are general-purpose, and can handle all kinds of problems whether
scientific or commercial.

Areas where mainframe computers are used:

Mainframe computers are mostly found in government departments, big organizations and companies
which have large information processing needs, e.g., they are used;
i. In Banks & Hospitals for preparing bills, Payrolls, etc.
ii. In communication networks such as the Internet where they act as Servers.
iii. By Airline reservation systems where information of all the flights is stored.

Examples of Mainframes:
i. IBM 4381.
ii. ICL 39 Series.
iii. CDC Cyber series.

c. Minicomputers
i. A Minicomputer is physically smaller than a mainframe. However, it can support the same
peripheral devices supported by a mainframe.

ii. A Minicomputer can support several users at a time, e.g., can be operated by 6 users at a time.
Several workstations/ terminals are connected to one central minicomputer so that the users
connected can share its resources (C.P.U time, storage, etc).

iii. Minicomputers are easier to manufacture & maintain compared to mainframes.

iv. Minicomputers are cheaper than the mainframes, but more costly than the microcomputers.

v. They handle small amounts of data, are less powerful, & have less memory than the mainframes.

vi. Minicomputers are slow compared to mainframe computers.

Areas where minicomputers are used

Minicomputers are used mainly in:
i. Scientific laboratories & research institutions.
ii. Engineering plants/factories to control of chemical or mechanical processes.
iii. Space industry.
iv. Insurance companies & Banks for accounting purposes.
v. Smaller organizations as Network Servers.

Example of Minicomputer: PDP-8 built in 1965 by Digital Equipment Corporation in U.S.

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d. Microcomputers
i. Microcomputers are the PCs mostly found today in homes, schools & many small offices. They are
called Personal Computers (PCs) because they are designed to be used by one person at a time.
ii. They consist of very few connected units, i.e. can support very few peripheral devices (usually 1 or 2).
iii. The data processing in microcomputers is done by a Microprocessor (a single chip containing the
Arithmetic Logic unit & Control unit).
iv. Microcomputers are smaller in size & also cheaper than minicomputers. Their design is based on
Very Large Scale Integration (VLSI) that confines several physical components into an IC.
v. They are less powerful than minicomputers & their internal memory is smaller than that of
minicomputers.

Areas where microcomputers are used

Microcomputers are commonly used in:
i. Training and learning institutions such as schools.
ii. Small business enterprises, and
iii. Communication centres as terminals.

Microcomputers have become very popular because of the following reasons:

i. Are cheaper than both mini & mainframe computers.
ii. Are very fast (i.e. have high processing speeds).
iii. Small in size, hence they occupy less space in an office.
iv. Are more energy efficient (i.e., consume less power).
v. Are more reliable than the early Mainframe computers.

Examples:
• IBM PCs such as Apple Macintosh, Dells, Compaq, etc.

e. Laptops & Notebooks.

i. A Laptop is a PC sufficiently small & light such that a user can use it comfortably on his/her lap. It
is designed to be used by placing it on the lap.
ii. Laptops are very small in size & are portable. They are small enough to fit inside a briefcase; still
leaving room for other items.
iii. A Laptop computer operates mainly on electricity or by rechargeable batteries.
iv. Laptops normally have in-built disk drives & Flat screens (Liquid Crystal Displays).
v. Can only support a limited number of peripheral devices.
vi. Have limited storage capacities.

Note. The smaller computers like Laptops tend to be more expensive than Desktop computers because
of the following reasons:

• The technology of producing smaller devices is expensive.

• They are convenient because they are portable.
• They have advanced power management capabilities (they consume less power since a laptop can
operate on rechargeable batteries).

f. Palmtops.
i.Palmtops are small enough to fit inside a pocket, and can be held in the palm when being used.
ii.Have limited storage capacities.
iii. Palmtops are mainly used as Personal Organizers, with some minimal programs for calculations,
Word processing, Spreadsheets, & E-mail.

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g. Desktop computer.
i. This is the name given to any computer designed to be used when placed on a desk in an office
environment.
ii. They are not portable.

Examples of desktop computers:

i. Home computer.
This is a low-cost microcomputer of limited capability designed for domestic use. It has programs
that are used typically for computer games or controlling family finances.

ii. Personal computer (PC).

This is a microcomputer designed for independent use by an individual at work or in the home
mainly for business purposes.
• A PC can support only 1 user at a time.
• PCs are mostly used in offices, schools, business premises, and at home for various
applications like computer literacy, Games, Database management, Accounting, Word
processing, Telecommunications, etc.
• A PC can be connected to a mini & mainframe computer so as to enable the user access the
facilities offered by the larger machines.

iii.Workstation.
A workstation is usually a desktop computer with all the facilities but interlinked to a network.

A typical workstation works in a similar way to a Personal computer. However, it is more advanced
than a typical PC in the following ways:
• It is larger & more powerful than a PC. E.g., workstations use 32-bit microprocessors, while
PCs use 16-bit microprocessors.
• It has in-built capabilities for its interconnection & operation with other computers, i.e., it is
fully connected to a computer network as any other computer on the network in its own right.
• It has high resolution graphics.
• It has a Multi-tasking operating system, i.e. it is able to run multiple applications at the same
time.

iv. An Embedded computer

This is a computer that is within another device or system but is not accessed directly. E.g., there are
embedded computers operating within Petrol pumps, Watches, Cameras & Video recorders.

2. Classification According to Purpose.

Computers can be classified further according to the tasks they perform either as:
• General-purpose.
• Special purpose
• Dedicated computers.

a. General-purpose computers
General-purpose computers are designed to perform a wide variety of tasks. They use specifically written
instructions (programs) to carry out the desired processing tasks.

A single computer can be used to process documents, perform calculations, process the Payroll, simulate the
loading on a bridge, process Insurance policies, and play games, among others.

The programs used in a general-purpose computer are exchangeable. This means that, to perform a
particular task, the appropriate set of instructions required to perform that particular task are loaded into the
computer memory.

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For example, if you want to play a game, the appropriate program is loaded into the computer’s memory &
the computer is instructed to execute the instructions which make up the game.
Examples of general-purpose computers:
• Mainframes,
• Minicomputers,
• Microcomputers and
• Laptops

b. Special-purpose computer
A special-purpose computer is designed to handle/accomplish a particular/specific task only.

Such computers cannot perform any other task except the one they were meant to do. Therefore, the
programs which are used in a special-purpose computer are fixed (hard-wired) at the time of manufacture.

For example;
In a computer Network, the Front End Processor (FEP) is only used to control the communication of
information between the various workstations and the host computer.

A Special-purpose computer is dedicated to a single task; hence it can perform it quickly & very efficiently.

Examples
• Robots used in a manufacturing industry for production only.
• Mobile phones used for communication only.
• Calculators that carry out calculations only.
• Computers used in Digital watches.
• Computers used in Petrol pumps.
• Computers used in Washing machines.
• An Automatic pilot – a computer dedicated to the task of operating an aircraft.
• A Word processor – a special-purpose computer used in the production of office documents,
letters, etc.

Reasons Why a Mobile Phone is regarded to be a Computer.

• It is electronic.
• Has a screen.
• It has a Keypad.
• Has a Memory.
• It is programmable.

c. Dedicated computer.
A Dedicated computer is a general-purpose computer that is committed to specific processing task; though
capable of performing a variety of tasks in different application environments.
E.g., the computer can be dedicated to carrying out Word processing tasks only.

3. Classification According to Functionality

Usually, there are two forms of data; Digital data, and Analogue data. Computers can be classified
according to the type of data they can process as either.
• Digital computers.
• Analogue computers, or
• Hybrid computers.

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a. Digital computers.
This is the most commonly used type of computers.

A Digital computer is a computer that operates on discrete data only. It can process both numeric &
alphabetic data within the computer, e.g., 0, 1, 2, 3…, A,B,C….

Their operation is based on 2 states, “ON” & “OFF” or on digits “1” & “0”. Therefore, any data to be
manipulated by a digital computer must first be converted to digital form.

Their output is usually in form of numbers, alphabets, & symbols. Digital computers are usually general-
purpose computers; hence, they are widely used in different areas for data processing.

Most of the devices found at homes today are digital in nature.

Digital computers are less accurate, i.e. may not solve all your problems since the facilities provided are
generalized.

Examples:
• A Television with a button which is pressed to increase or decrease the volume.
• Digital watches.
• Calculators.
• Microcomputers. They are said to be digital because they posses the ALU.

b. Analogue computers.
An Analogue computer is a computer that operates on continuous data.

They carry out their data processing by measuring the amount of change that occurs in physical
attributes/quantities, such as changes in electrical voltage, speed, currents, pressure, length, temperature,
humidity, etc.

An Analogue computer is usually a special-purpose device that is dedicated to a single task. For example,
they are used in specialized areas such as in:
• Scientific or engineering experiments,
• Military weapons,
• Controlling manufacturing processes like monitoring & regulating furnace temperatures and
pressures.
• Weather stations to record & process physical quantities, e.g., wind speed, cloud coverage,
temperature, etc.

The output from analogue computers is in form of smooth graphs produced by a plotting pen or a trace on a
Cathode Ray Tube (CRT) from which the information can be read.

Note: Analogue computers usually use one characteristic, e.g. a length, to give information about another
physical characteristic, such as weight.

Analogue computers are very accurate & efficient since they are dedicated to a single task. They are very
fast since most of them use multiple processors.
Examples of analogue devices:
• Flight Simulators: - The computer responds to the Cockpit simulator control movements made
by the pilot to physically change the environment so that the pilot feels as if he were controlling
an actual aeroplane.
• Bathroom scale: - It uses the weight of a person to move a pointer smoothly/continuously over
calibrated scale, which shows the person’s weight.

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 • Thermometer: - It uses a volume of Mercury to show temperature. The Thermometer is
calibrated to give an exact temperature reading.
• Speedometer: - In Speedometer, the rotation of the wheel is converted to a voltage, which causes
a pointer to rotate over a dial calibrated in Km/h or Miles/h.
• A Petrol Pump: - measures the rate of flow of Gasoline (petrol) & converts the volume delivered
to 2 readings; one showing the volume & the other showing the cost.
• A Post-office scale: - converts the weight of a parcel delivered into a charge for posting.
• A Monitor with knobs that are rotated to increase brightness.
• A Television with knobs that are rotated to increase or decrease the volume.
• A Radio with a knob that slides in a slot to increase volume.

c. Hybrid Computers
Hybrid computers are designed to process both analogue & digital data. They combine both the functional
capabilities of the digital and analogue computers.

Hybrid computers are designed by interconnecting the elements of a digital computer & analogue computer
directly into one processor, using a suitable interfacing circuitry.

Hybrid computers are more expensive.

Example
• In a hospital Intensive Care Unit, an analogue device may be used to measure the functioning of
patient’s heart, temperature and other vital signs. These measurements may then be converted into
numbers and send to a digital device, which may send an immediate signal to the nurses’ station if
any abnormal readings are detected.

FEATURE ANALOG COMPUTERS DIGITAL COMPUTERS

SIGNAL Continuous signal that represents Discrete time signals generated by
physical measurements digital modulation
WAVES Denoted by sine waves Denoted by square waves
REPRESENTATION Uses continuous range of values Uses discrete or continuous range of
to represent information values to represent information
TECHNOLOGY Records waveforms as they are Samples analog waveforms into a
from physical attributes. limited set of numbers and records
them
DATA Signal strength deteriorates due Signal strength is rarely affected by
TRANSMISSION to noise during transmission and noise during transmission and
write/read cycle. write/read cycle.
FLEXIBILITY Analog hardware is not flexible Digital hardware is flexible hence
easy implementation
BANDWIDTH Signal processing is done in real No guarantee that processing can be
time hence less bandwidth done in real time and thus consumes
more bandwidth
MEMORY Stored in the form of a wave Stored in the form of a binary bit
signal
POWER Analog instruments draw large Power used is less/negligible
power
COST Low cost Cost is high
IMPEDENCE Low High
ERRORS Analog instruments contain a Digital instruments are free from
scale cramped at the lower end observational errors like parallax
to give observational errors and approximation.
USES Analog devices Computing and digital electronics
APPLICATIONS Thermometer PCs, PDAs, TVs, Radio

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Comparison between a Computer and Calculator

Computer Calculators
1. Costly due to the technology used. 1. Cheaper – they imitate simple computer
technology.
2. Bigger in size. 2. Comparatively smaller.
3. Operate at very high speeds. 3. Slower than computers.
4. Are more accurate – they give up to over 10 4. Less accurate – most calculators give up to 8 dp of
decimal places of accuracy. accuracy.
5. Flexible – can be used in solving any 5. Mostly used for numerical calculations involving
problem. arithmetic/ mathematical operations
6. Work under the control of programs. 6. Calculators are non-programmable, but if
programmable, the range is limited.
7. Support a variety of peripherals, e.g. 7. They only use Display units & Keyboards of
keyboard, mouse, light pen, printer, etc. limited capabilities.
8. Have large internal memory of several KB’s. 8. their internal memory is very small. Most
calculators only use Registers for temporary
9. Support large Backing storage media. storage during calculations.
9. Some calculators have got some sort of fixed
10. A computer can support several people at the Backing store, though very limited.
same time. 10. A calculator can serve only 1 user at a time.
11. Have got telecommunication capabilities.
12. Require well-monitored environmental 11. Have no telecommunication capabilities.
conditions. 12. Do not require well-monitored environmental
conditions.

Advantages of Using Computers

Computers have many advantages over other types of office and business equipments that are used for data
processing functions. Some of the advantages are:

1. Computers process data faster: - The processing speed of a computer when measured against other
devices like typewriters & calculators is far much higher.
2. Computers are more accurate & reliable: - Computers produce more accurate results as long as the
correct instructions & data are entered. They also have the ability to handle numbers with many
decimal places.
3. Computers are more efficient: - A computer requires less effort to process data as compared to
human beings or other machines.
4. Computers can quickly and effectively store & retrieve large amounts of data.
5. They are very economical when saving information, for it can conserve a lot of space.
6. Computers occupy very little office space.
7. Computers help to reduce paper work significantly.
8. Computers are flexible: - A computer can perform a variety of jobs as long as there is a well-defined
procedure.
9. Computers are cheap: - They can be used to perform a number of organizational functions/
activities, which are meant for individual persons, hence reducing the number of employees & the
costs.
10. Computers enhance security & confidentiality: - Data stored in a computer can be protected from
unauthorized individuals.
11. Have made communication easier.
12. Computers produce better information: - Computer output is usually tidy and error-free (accurate).
13. Computers reduce the problems of data or information duplication:
14. Computers can operate in risky environments, e.g. volcanic sites, dangerous chemical plants, where
human life is threatened:
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Disadvantages of Using Computers
1. Computers are very costly in terms of purchase & maintenance.
2. Computers can only be used in areas where there is a source of power.
3. Requires skilled manpower to operate, i.e., one has to have some knowledge so as to operate a
computer.
4. The records are usually kept in a form that is not visible or human-readable. This makes it difficult
to control the contents of the computer’s master file.
5. A computer, like any other machine can break down.
6. Information stored in computers can easily get lost due to power interruptions or machine
breakdown.
7. A computer doesn’t have its own intelligence, i.e., it cannot do any useful job on its own, but can
only work as per the set of instructions issued.
8. Installation of computers causes retraining or retrenchment of staff/employees.
9. The computer technology is changing very fast such that the already bought computers could be
made obsolete/ out dated in the next few years.
10. In addition, this rapid change in the computer technology makes computers & related facilities to
become outdated very fast, hence posing a risk of capital loss.
11. The emergence of computers has increased the rate of unemployment since they are now being used
to perform the jobs, which were done by human beings.
12. Computers have led to increase in computer crimes especially in Banks. The computer criminals
steal large amounts of funds belonging to various companies by transferring them out of their
company accounts illegally. In addition, they destroy vital data used in running the companies.

Application Areas of Computers

The following are some of the areas where computers are used:

1. Supermarkets
- Supermarkets and other retail stores use computers for stock control, i.e., to help them manage their
daily activities.
The stock control system keeps record of what is in store, what has been sold, and what is out of stock.
The Management is automatically alerted when a particular item or items are running out of stock and
need to be reordered.
- For calculating customer’s change.
- For production of receipts.
- It can be used as a barcode reader.

2. Industries
The use of computers has made Industries more productive & efficient. They are used:
− To monitor and control industrial processes. The industries use remote controlled devices called
Robots. A Robot is a machine that works like a human being, but performs tasks that are unpleasant,
dangerous, and tedious to be done by human beings.
− For management control, i.e. to keep track of orders, bills and transactions.
− By companies as a competitive tool. E.g., they are used to assist in defining new products & services.
They also help industries form new relationships with suppliers and therefore, enable the producers
maintain a competitive edge against their competitors.
− For advertisement purposes, which enable an industry to attract more customers.

3. Banks/Insurance industries
Computers are used by Banks & Insurance industries:
− To manage financial transactions. They use special cash dispensing machines called Automated
Teller Machines (ATMs) to enable them provide cash deposit & withdrawal services.
− For processing of Cheques.
− For preparation of Payrolls.
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 − For better record keeping and processing of documents.
− To provide electronic money transfer facilities.

4. Process Control
Computers are used in production environments such as factories to control chemical & mechanical
processes. The computers are usually loaded with specialized programs & each computer is designed to
do a specific job.

5. Hospitals
Computers are used in hospitals:
− To keep & retrieve patient’s medical records.
− For automatic diagnosis of diseases like Cancer, electro-cardiogram screening & monitoring.
They are used to get a cross-sectional view of the patient’s body that enables physicians to properly
diagnose the affected part of the body with high levels of accuracy.
− In medical equipments, e.g. blood pressure monitors, blood analysers, etc.
− To control life-supporting machines in the Intensive Care Units (ICU).
− To enable medical experts in different countries to share their expertise or labour, thus reducing the
transportation of patients & professionals.

6. Offices
− For receiving & sending of messages through e-mails, fax, etc.
− Production of documents.
− Keeping of records.

7. Government Institutions.
Computers are used in government ministries & agencies:
− To store/keep records and improve the efficiency of work within the Civil service.
If computers were not used, the large number of files in government registries would make information
recovery extremely difficult.
− To produce bills & statements.

8. Education
Computers are widely used in the teaching & learning process. Learning and teaching using computers
is referred to as Computer Aided Learning (CAL) and Computer Aided Teaching (CAT).

− Computers are used in learning institutions (schools & colleges) as teaching aids, i.e. to help in
teaching various subjects. e.g., they are used to demonstrate experiments in subjects like Chemistry or
Physics using a special program that can illustrate them on the screen through a process called
Simulation.
− To assist the Long-distance learning in universities usually referred to as the Open University Concept.
− To analyze academic data.
− Computers are used in Aviation for training of pilots. Flight simulators are used to monitor the
control movements made by the pilot while the computer is used to physically change the environment
so that the pilot feels as if he were controlling an actual aircraft.

9. Research
Computers can be used for research in various fields. They are used by:
− Scientists to analyse their experimental data, e.g., in weather forecasting.
− Engineers & Architects to design & test their work.
− Computers have greatly assisted in space exploration.
 They are used to study the movement of stars.
 They have made manned & unmanned space exploration possible – they are used to launch
space vehicles and monitor the flights & activities both onboard and around them.
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10. Communication Industry
The integration of computers & telecommunication facilities has made the transmission and reception of
messages very fast and efficient.
− They are used in telephone exchanges to switch incoming & outgoing calls.
− For sending & receiving electronic messages, e.g. fax and e-mails, if connected to a computer network.

11. Transport Industry

Computers are used in:
− Automobile traffic control, e.g., to monitor vehicle traffic in a busy town.
− Railway corporations to co-ordinate the movement of their goods & wagons.
− Shipping control. The computers are used for efficient management of fleets & communication.
− Airports (Airline industry). The computers are used;
 To control the movement of aircrafts, take off & landing through the use of radar
equipment.
 Making reservations (booking purposes).
 Storing flight information.

12. Police (Law Enforcement Agencies)

− Computers are widely used in fighting crime. The Police use computers to keep databases on
fingerprints and also analysed them.
− The Police also use computers for face recognition, scene monitoring & analysis, which help them to
arrest traffic offenders and criminals.
− The information held in computers such as fingerprints, photographs and other identification details
helps law enforcers to carry out criminal investigations speedily.

13. Defence
− Computers are used in electronic news gathering, efficient communication, detecting and tracking of
targets; in radar systems, warning systems & in guided missile systems.
− Computers are used in military defence equipments, e.g. Fighter jets, Rockets, Bombers, etc.

14. Multimedia Applications

− Computers are used to prepare business presentations for advertisement purposes.
− The presentations are done using overhead projectors attached to computers running slide shows &
digital video clips taken using a Camcorder. An overlaid voice is used to describe the product.
− Computers are used in music related equipment such as Synthesizers.
− In entertainment (i.e., games & movies), computers are used to add stereo sound & digital video clips,
which make games more realistic.
− In Education & Training, Multimedia discs are used as teaching aids for all types of subjects.

15. Domestic and Entertainment Systems

Computers are used at homes:
− For watching movies, playing music and computer games.
− For storing personal information.
− For calculating and keeping home budgets.
− For shopping purposes. They provide people with lists of shopping items as well as their prices. They
also provide electronic money transfer facilities.
− In household items, such as, Microwave ovens, Televisions, etc.

16. Library Services

Computers can be used in a library:
- To enable the library personnel to easily access & keep updated records of books and other library
materials.
- To search for book titles instead of using the manual card catalogue.
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17. Employment
The emergence of computers has provided employment opportunities to very many people.

Factors to Consider When Selecting a Computer

1. Type of processor (Central processing unit – CPU)
Microcomputers use microprocessors, which are manufactured on a single chip, as their CPU.
In larger computers such as supercomputers, mainframe & minicomputers, the processing is carried out by a
number of separate, high-speed components instead of a single processor.

2. Processing Speed
Every computer has a clock that drives its operations. Larger computers have faster clocks and therefore can
process many instructions per second compared to small computers, which have slower clocks.

3. Amount of Main Memory (RAM)

All computers have some amount of RAM (Random Access memory), which is used to hold the
instructions required to perform a task.

Larger computers have more RAM and therefore can handle large volumes of data & also support many and
sophisticated programs which might require large memory sizes.

4. Storage Capacity of the Hard Disk

The storage capacity is the amount of space that is available for storing the instructions required to
manipulate data. Larger computers have higher storage capacities than microcomputers.

5. Cost of the Computer

The cost of computers is directly related to the size. Microcomputers are less costly compared to
minicomputers, mainframes or Supercomputers.

6. Speed of Output devices

The speed of an output device is determined by the amount of information that can be printed in a specified
amount of time.

The speed of microcomputer output device is less than that of the larger computers in that:

For a microcomputer, the speed of its output device is measured by the number of characters printed per
second (cps). For larger computers, their output devices are faster and their speeds are measured depending
on the number of lines or pages printed per minute (lpm / ppm).

7. Number of users who can access the computer at the same time
Most microcomputers can support only 1, 2 or 3 users at the same time. However, they can be networked to
share resources.

Larger computers can support hundreds of users at the same time.

Computer Laboratory
Definition:
A Computer laboratory is a room that has been specially prepared to facilitate installation of computers, and
provide a safe conducive environment for teaching & learning of Computer Studies.

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Factors to Consider When Preparing a Computer Laboratory
The following factors must be considered when preparing a computer laboratory:
• Security of the computers, programs and other resources.
• Reliability of the source of power.
• Number of computers to be installed, and the amount floor space available.
• The maximum number of users that the laboratory can accommodate.

Requirements of a Computer Laboratory

• Standard and Enough furniture.
• Good ventilation.
• Reliable & Enough source of power supply.
• Free from Dust and Moisture.
• Enough floor space.
• Proper cabling of electric wires.
• Fire fighting equipment.
• Good lighting equipment.
• Strong rooms & doors for the security of computers.

Laboratory Layout
• The computer laboratory should have enough floor space to facilitate free movement from one place to
another.
• The laboratory furniture must be well arranged to prevent accidents.
• Your working surface must be large enough to hold the computer equipment & any other additional
items required. This prevents squeezing the devices together & also minimizes breakages.
• The sitting arrangement of users should be proper.

Safety Precautions & Practices in a Computer Laboratory

After establishing the computer laboratory, a number of safety precautions, rules, and practices need to be
observed in order to avoid accidental injury to the users, damage of computers or lack of a conducive
environment for teaching and learning.

The safety precautions and practices include:

1. Behaviour in The Computer Laboratory

The following rules must be followed in and around a computer laboratory.

a. Entering the computer room

• Only authorized people should enter the computer room.
• Avoid smoking or exposing computers to dust. This is because; smoke & dust contain small
abrasive particles that can damage computer components and cause wearing of the moving
parts.
• Do not carry foods such as Toffees, chocolates, chewing gums, & drinks/beverages to the
computer room. Food particles may fall into the moving parts of the computer and damage
them. Liquids may spill into the computer parts causing rusting or electrical faults.
• Collect any waste materials (e.g., paper bits) which might be lying in the computer room &
put them into the dustbin.
• Avoid unnecessary movements, because you may accidentally knock down the peripheral
devices.
• Computer users should be trained on how to use computers frequently.
• Computer illiterates should not be allowed to operate the computers.
• Shut the door of the computer room properly.

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 b. Starting and shutting down the computer
• Always follow the proper procedure for starting & shutting down the computer to avoid loss
of data and damage to computer programs.
• Avoid turning the computer on & off frequently as it is harmful. Every time a PC is turned
on, the internal components get heated and again cool down when the computer is turned off.
As a result, the circuit boards expand & contract and this can badly affect the solder-joints
of the computer.
• Do not open up the metallic covers of computers or peripheral devices without permission
and particularly when the computer’s power is still on.

2. Safe Use & Care of Computers

Computer systems are expensive to acquire & maintain, and should therefore be handled with great care.
Most computer breakdowns are caused by failure to follow the correct instructions on use of equipment,
carelessness, and neglect.

Computer hygiene involves keeping the computers in good care & order.

a. Protection against Fire and Accidents

Fire outbreaks in the laboratory can be caused by either:
• Inflammable chemicals, such as those used for cleaning & servicing the computer equipment.
• Electrical faults, such as open wires or cables.
• Smoking

To avoid accidents in the laboratory:

• Keep the chemicals away in a store after using them to avoid any accidents.
• Ensure that all electrical wires are properly insulated. Open wires or cables must be properly
covered with an Insulating tape or replaced with new ones as they can cause fire leading to damage
of equipment.
• The computer room must always have a gaseous fire extinguisher especially those containing
Carbon dioxide in case of any accidents.
o Note. Water based or Powder extinguishers should not be used in the computer room
because; they can cause damage to computer components.
o Water causes rusting of the metallic parts and short circuits, while Powder particles normally
settle on storage devices and may scratch them during read/write operations.
• Any incidence that may result in damage to equipment should be reported to the person in charge of
the laboratory.
• No student should attempt to repair the equipment as this may lead to complete damage of the
equipment.

b. Insulation of Cables
• All power cables in the computer room must be properly insulated and laid away from busy
pathways in the room (i.e., preferably along the walls). This prevents the user from stumbling on the
cables, which might cause electric shock or power interruptions.

• System cables should be of the best quality & type, and should also be properly clipped (fixed).
• The cables should be handled carefully especially at the ends to avoid breaking the pins.

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 c. Stable Power Supply
Computers are delicate devices that require a stable source of power.

Ensure that there is a steady flow of input power to the computer in order to prevent loss of data or
information & also prevent damaging the computer’s secondary storage media.

Note. Power from main supply is not always stable and may sometimes experience power surges or under
voltage (also referred to as Brownout). To protect the computer from being damaged due to power
instabilities especially in areas where power fluctuates, avoid connecting it directly to the main supply.
Instead, it is important to connect the computer to a special power correction equipment or device such as a
Stabilizer or Uninterrupted power supply /source (UPS), then connect the UPS to the main supply.

The UPS gets charged when the main power is on. When the main power goes off, the UPS gives some
sound (usually a beep) to alert the user.

Functions of the UPS

• It regulates power from an unstable power source to the required clean stable voltage.
• It prevents power surges and brownouts that might destroy the computer.
• It temporarily provides power to the computer in case of the main power failure. This allows the
user to save his/her work and shutdown the computer using the correct procedure
• Alerts the user of any power loss (by beeping).

To ensure that work continues even in the absence of main power, organizations that give important
services such as banks, schools, & hospitals usually install devices that provide alternative sources of
power such as standby generators, solar panels, rechargeable batteries, etc that automatically comes on
in case of a power failure. Such devices are referred to as Power backups.

However, note that, power from a generator must pass through a UPS before being fed to the computer,
because it is also not stable. Ensure that all power or electrical sockets are firmly fixed.

d. Burglar Proofing
Physical access to the computer room should be restricted to ensure that only authorized persons get access
to the computers.
To prevent unauthorized access to the computer room, the following controls should be implemented:
• Fit strong metallic grills and locks on the doors, windows & roofs (in case the roofing is weak).
• Lock the doors, (i.e., keep the computers in a strong room, which should remain firmly locked when
not in use).
• Avoid welcoming strangers into the computer room.
• Use of Personal Identification cards.
• Use of fingerprint identification.

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 • Install security alarms at strategic access points so as to alert the security personnel in case of a break
in.
• Use of special voice recorders that would be able to analyse the voice of a trespasser & check against
the database containing the voice patterns of valid users.
• Secure/protect the computers with Passwords to minimize chances of theft.

e. Ventilation
Both computers and human beings emit heat energy into the environment. Therefore, the computer room
must have good circulation of air to avoid overheating and suffocation.

Proper ventilation enables the computers to cool, and therefore, avoids damaging the electronic parts.

The following facilities can ensure proper ventilation in a room:

• The room should have large & enough windows & doors.
• Installing an air-conditioning system.
• Installing cooling fans.
• Avoid overcrowding of either machines or people in the room.

f. Dust Control
Dust can affect the functioning of the computer system. To keep the computer lab dust free:
• Set up the computer laboratory in a location away from excessive dust.
• The computer room should be fitted with special curtains that would reduce entry of dust particles.
• The floor should be covered with Carpets in order to absorb dust, and also absorb the noise made by
chairs.
• Cover the computer devices with Dust covers when not in use or when cleaning the computer room.

NB: If the environment is dusty, the computers should be regularly serviced to get rid of harmful dust.
The service should include; blowing dust from the System unit, cleaning the floppy drives, cleaning the
Keyboard, cleaning the Monitor externally, and also cleaning all peripheral devices such as Printers and
Mouse.

g. Humidity Control
Humidity in the computer laboratory must be regulated to remain at an optimum 50%. If the humidity is
low, it allows static electricity to build up and causes damage to sensitive electronic components. Similarly,
high humidity of over 70% causes rusting of the metallic parts of the computer system.

To eliminate low humidity, place humidifiers in the room, while high humidity can be controlled by
installing dehumidifiers in the room.

h. Handling of Materials & Equipment

Computer devices must be handled with a lot of care as they are extremely fragile and can easily get
damaged. Dropping or bumping can cause permanent damage on the device, e.g., to transport the System
unit always handle it on its frame.
• Always use the manufacturer’s shipping carton when transporting the devices.
• Do not place heavy objects on the computers.
• Protect the computer devices especially the Monitor & the disks from any electrostatic discharge.
• The computer devices should not be exposed to direct sunlight or warm objects. This causes the
internal components of the computer to get heated, and as a result, effects the computer’s solder-
joints.
• Students should only perform operations on the computer that they are sure of and under supervision.
If in doubt, the student should ask to ensure that no damage is caused due to lack of proper
knowledge.
• Computer equipment should be regularly checked and serviced.
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 i. Standard Furniture & Posture
• The table/bench on which a computer is placed must be strong and wide enough to bear the weight
and accommodate all the peripheral devices.
• The seat for the user must be comfortable, and have a straight backrest that allows someone to sit
upright. This prevents muscle pains & backaches caused by poor sitting posture.
• Adjust the furniture to meet your needs for comfort. For example,
o Adjust the height of the chair or working surface so that your forearms are parallel with the floor
and your wrists are straight.
o The seat must be high enough relative to the table to enable the user use the hands on the
keyboard comfortably.
o The eyes must be at the same level with the top of the screen when the user is seated upright.
• You should be able to maintain your proper arm position and place your feet firmly flat on the floor.
• Adopt a relaxed, upright working posture. Avoid slouching (bending) forward or leaning far
backwards.
• The Chairs should have low back support & footrest and should also be adjustable.

j. Keyboard, Mouse and Input devices

Place frequently used work materials within easy reach.
• The Keyboard, Mouse & other input devices should be positioned such that your hands are in a
relaxed, comfortable position.
• Position the Keyboard directly in front of you. This makes it possible to type with your shoulders
relaxed and your upper arms hanging freely at your sides.
• Position the Mouse at the same level as the keyboard.

k. Lighting & Vision Care

A computer room must be well lit to avoid eyestrain that eventually leads to headaches, stress, and fatigue.
Similarly, when you work at your computer for long periods of time, your eyes may become irritated.

Therefore, special care should be given to your vision.

• Tilt the computer so that the display faces away from the windows. This will minimize glare (or bright
reflections) on the screen.
• Position the lighting equipment or sources of light such that glare (or bright reflections) on the display
are minimized. Where necessary, use indirect lighting to avoid bright spots on the display.
• Use/fit radiation filter screens that are specially tinted to reduce the light that reaches the eye.
• Avoid using a flickering monitor. This causes extreme eyestrain that can damage your eyesight.
• The wall paints used should not be very bright as they reflect too much light causing eyestrain.
• Use the brightness & contrast controls on the Monitor to adjust the brightness of the computer monitor
until the eyes feel comfortable, and also to improve image quality of your display.
• Turn off the screen when not in use or reduce its brightness in order to prevent screen burnout.
• If the room has windows, use blinds or shades to control the amount of daylight in the room.
• Take frequent breaks and rest your eyes.
• You should have glasses that are specifically suited for working with the computer display.
• Keep your glasses and the display clean.
• Have your eyes examined regularly by a vision care specialist.
• The distant between the user & screen should be between 450 – 500 mm.

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