Computer Hardware
INTRODUCTION TO COMPUTERS.
Definition of a Computer:
A Computer is an electronic device that operates (works) under the control of programs
stored in its own memory unit.
A computer is an electronic machine that processes raw data to give information as output.
An electronic device that accepts data as input, and transforms it under the influence of a set
of special instructions called Programs, to produce the desired output (referred to as
Information).
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 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 the language of the computer
& is used to make the computer perform a specific task (or, to direct the computer on what to
do).
A set of related instructions which specify how the data is to be processed.
A set of instructions used to guide a computer through a process.
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.
-1-
, Computer Hardware
Data Processing:
It is the process of collecting all items of data together & converting them into information.
Processing refers to the way the data is manipulated (or handled) to turn it into information.
The processing may involve calculation, comparison or any other logic to produce the required
result. 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 the way you want
it, 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.
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.
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.
-2-
, Computer Hardware
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.
Review Questions.
1. What is a Computer?
2. Why is a computer referred to as an electronic device?
3. Define the following terms as used in computer science.
a). Data.
b). Programs.
c). Data processing.
d). Information.
4. (a) Briefly explain the two forms of data.
(b) Give THREE differences between Data and Information.
5. The speed of a computer is measured in ___________.
6. What does the term GIGO stands for?
7. List and explain 4 salient features/ properties of a computer.
8. List FIVE advantages of a computerized system over a manual system.
-3-
, Computer Hardware
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: -
1. The System Unit.
2. Input devices.
3. Output devices.
4. Storage devices.
System Unit.
This is the casing (unit) that houses electronic components such as the ‘brain’ of the computer
called the Central processing Unit (CPU) and storage devices.
The components in the System unit include: -
Central Processing Unit (CPU), which is also referred to as Processor.
Motherboard.
Power supply unit.
Memory storage devices.
Disk drives, which are used to store, record and read data.
Types of System units
There are two makes of System units:
a) Tower style system unit
This system unit is made to stand alone. They are designed to be placed on the floor.
Tower style units have more space for expansion than the typical desktop units.
b) Desktop system units
Desktop units lie on the desk with the monitor resting on top of the system unit.
Features of the System unit.
It houses the CPU.
It connects to all peripheral devices using ports.
It has the computer’s Power switch.
-4-
INTRODUCTION TO COMPUTERS.
Definition of a Computer:
A Computer is an electronic device that operates (works) under the control of programs
stored in its own memory unit.
A computer is an electronic machine that processes raw data to give information as output.
An electronic device that accepts data as input, and transforms it under the influence of a set
of special instructions called Programs, to produce the desired output (referred to as
Information).
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 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 the language of the computer
& is used to make the computer perform a specific task (or, to direct the computer on what to
do).
A set of related instructions which specify how the data is to be processed.
A set of instructions used to guide a computer through a process.
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.
-1-
, Computer Hardware
Data Processing:
It is the process of collecting all items of data together & converting them into information.
Processing refers to the way the data is manipulated (or handled) to turn it into information.
The processing may involve calculation, comparison or any other logic to produce the required
result. 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 the way you want
it, 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.
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.
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.
-2-
, Computer Hardware
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.
Review Questions.
1. What is a Computer?
2. Why is a computer referred to as an electronic device?
3. Define the following terms as used in computer science.
a). Data.
b). Programs.
c). Data processing.
d). Information.
4. (a) Briefly explain the two forms of data.
(b) Give THREE differences between Data and Information.
5. The speed of a computer is measured in ___________.
6. What does the term GIGO stands for?
7. List and explain 4 salient features/ properties of a computer.
8. List FIVE advantages of a computerized system over a manual system.
-3-
, Computer Hardware
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: -
1. The System Unit.
2. Input devices.
3. Output devices.
4. Storage devices.
System Unit.
This is the casing (unit) that houses electronic components such as the ‘brain’ of the computer
called the Central processing Unit (CPU) and storage devices.
The components in the System unit include: -
Central Processing Unit (CPU), which is also referred to as Processor.
Motherboard.
Power supply unit.
Memory storage devices.
Disk drives, which are used to store, record and read data.
Types of System units
There are two makes of System units:
a) Tower style system unit
This system unit is made to stand alone. They are designed to be placed on the floor.
Tower style units have more space for expansion than the typical desktop units.
b) Desktop system units
Desktop units lie on the desk with the monitor resting on top of the system unit.
Features of the System unit.
It houses the CPU.
It connects to all peripheral devices using ports.
It has the computer’s Power switch.
-4-
