INTRODUCTION TO COMPUTERS
Definition of terms
A computer
Is an electronic device that accepts user input (data) and processes it under the influence of a
set of instructions referred to as programs to produce desired output (information).
Is an electronic device that uses instructions (programs) to accept and process data given to it
in a variety of forms in order to produce useful information.
Is an electronic device that accepts user input (data) and transforms it under the influence of
sets of special instructions called programs to produce information.
A computer is said to be electronic because it utilizes electrical signals to process information.
The four key terms that define a computer are:- electronic device, input(data), process and
output(information).
Programs
Set of instructions written in computer language that directs the computer what task to perform
and how to perform it.
Data
Raw facts that do not have much meaning to the user. Includes alphabets, numbers and symbols.
Data processing
The varied activities performed to convert data into useful information.
Information
Processed data that is meaningful to the user and which can form a basis for decision making.
Information and Communication Technology (ICT)
Is the integration of computers and telecommunication facilities for the purpose of
communication.
Functions of a computer
Convert raw data into information
Store information and data
Projections eg weather forecasting
Process control eg when using special computer to control movement of rockets
Advantages of computers include:
Speed – Computers have higher processing speeds than other means
of processing, measured as number of instructions executed per
second.
Accuracy – Computers are not prone to errors. So long as the
programs are correct, they will always give correct output. A
computer is designed in such a way that many of the inaccuracies,
which could arise due to the malfunctioning of the equipment, are
detected and their consequences avoided in a way, which is
completely transparent to the user.
Consistency – Given the same data and the same instructions
computers will produce exactly the same answer every time that
particular process is repeated.
Reliability – Computer systems are built with fault tolerance
features, meaning that failure of one of the components does not
necessarily lead to failure of the whole system.
Memory capability – A computer has the ability to store and access
large volumes of data.
Processing capability – A computer has the ability to execute
millions of instructions per second.
Disadvantages of a computer
, - Computer are relatively expensive
- Computer technology changes too often
- Computer can break down
- Computer does not have its own intelligence
- Computers causes job displacement
- Installation of computers require training of staff
Physical Parts of a Computer
A computer is made up of a collection of different components that are interconnected together
in order to function as a single entity. A computer is basically made up of four basic components
and other devices connected to the system unit called peripheral devices.
i). System unit
A computer case (also known as a computer chassis, cabinet, box, tower, enclosure, housing,
system unit or simply case) is the enclosure that contains most of the components of a computer
(usually excluding the display, keyboard and mouse).
This part houses the brain of the computer called the Central Processing Unit (CPU),
motherboard, main memory, and the drives. The drive is used to store, record and read data. The
two common types of system units are Tower and desktop type.
ii). Peripheral devices
Can be defined as:-
- Devices that are connected to the system unit via ports and controlled by the CPU; or
- hardware that is externally connected to the computer’s system unit
Most of the devices are connected using data interface cables. The interface cables carry
data and information to and from the devices. The cables are attached to the system unit using
connectors called ports.
Some peripheral devices are:-
Keyboard
Definition of terms
A computer
Is an electronic device that accepts user input (data) and processes it under the influence of a
set of instructions referred to as programs to produce desired output (information).
Is an electronic device that uses instructions (programs) to accept and process data given to it
in a variety of forms in order to produce useful information.
Is an electronic device that accepts user input (data) and transforms it under the influence of
sets of special instructions called programs to produce information.
A computer is said to be electronic because it utilizes electrical signals to process information.
The four key terms that define a computer are:- electronic device, input(data), process and
output(information).
Programs
Set of instructions written in computer language that directs the computer what task to perform
and how to perform it.
Data
Raw facts that do not have much meaning to the user. Includes alphabets, numbers and symbols.
Data processing
The varied activities performed to convert data into useful information.
Information
Processed data that is meaningful to the user and which can form a basis for decision making.
Information and Communication Technology (ICT)
Is the integration of computers and telecommunication facilities for the purpose of
communication.
Functions of a computer
Convert raw data into information
Store information and data
Projections eg weather forecasting
Process control eg when using special computer to control movement of rockets
Advantages of computers include:
Speed – Computers have higher processing speeds than other means
of processing, measured as number of instructions executed per
second.
Accuracy – Computers are not prone to errors. So long as the
programs are correct, they will always give correct output. A
computer is designed in such a way that many of the inaccuracies,
which could arise due to the malfunctioning of the equipment, are
detected and their consequences avoided in a way, which is
completely transparent to the user.
Consistency – Given the same data and the same instructions
computers will produce exactly the same answer every time that
particular process is repeated.
Reliability – Computer systems are built with fault tolerance
features, meaning that failure of one of the components does not
necessarily lead to failure of the whole system.
Memory capability – A computer has the ability to store and access
large volumes of data.
Processing capability – A computer has the ability to execute
millions of instructions per second.
Disadvantages of a computer
, - Computer are relatively expensive
- Computer technology changes too often
- Computer can break down
- Computer does not have its own intelligence
- Computers causes job displacement
- Installation of computers require training of staff
Physical Parts of a Computer
A computer is made up of a collection of different components that are interconnected together
in order to function as a single entity. A computer is basically made up of four basic components
and other devices connected to the system unit called peripheral devices.
i). System unit
A computer case (also known as a computer chassis, cabinet, box, tower, enclosure, housing,
system unit or simply case) is the enclosure that contains most of the components of a computer
(usually excluding the display, keyboard and mouse).
This part houses the brain of the computer called the Central Processing Unit (CPU),
motherboard, main memory, and the drives. The drive is used to store, record and read data. The
two common types of system units are Tower and desktop type.
ii). Peripheral devices
Can be defined as:-
- Devices that are connected to the system unit via ports and controlled by the CPU; or
- hardware that is externally connected to the computer’s system unit
Most of the devices are connected using data interface cables. The interface cables carry
data and information to and from the devices. The cables are attached to the system unit using
connectors called ports.
Some peripheral devices are:-
Keyboard
