Computer is an electronic device which can be
programmed to accept data, process it into
information, store it for safe keeping or send
it to another device.
It can also be define as an electronic device,
operating under the control of instructions
stored in it memory, that can accept data,
process that data according to specified rules,
produce results, and store the results for
The computer system :
The computer system consists of the
Hardware, Software, Live ware and
They are parts of the computer system that
are tangible, thus it can be touched and seen.
They include, 1) system units 2)input devices
3)output devices 4)storage devices
They are non tangible part of a computer.
1)System software and
Live ware :
They design both the hardware and the
They send data for the system to process.
Connec tivi ty:
Connectivity is the capability of the
microcomputer to use information from the
world beyond one’s desk.
How computers are classified
All computers are not the same. Computers
come in various forms and and used for
various purposes. Computer can be classified
purpose, by size /capacity and by type.
By purpose ,
we have general purpose computers and
special purpose computers.
General purpose computers are designed to
perform variety of tasks. Thus they are
designed to solve a wide range jobs. They are
used for task like budgeting, accounting,
banking and scientific analysis.
Special purpose computers are designed to
perform a specific task. Examples are
microwave oven, washing machine, digital tv,
They are three types of computers, these are :
1)Analog, 2)Digital 3)Hybrid
Analog computers are named because the
perform computations by setting up physical
situation that are analogous to mathematics
situations.Analog computers calculate by
measuring the continuous variation in physical
quantities. Example, thermometer,
Digital computers perform tasks by counting
devices. it solve problems by counting
precisely, adding, subtracting, multiplying, etc,
they are basically use in data processing.
Hybrid, They are mostly use in the industries.
It combine analog and digital capabilities in
the same computer system. Example,
ATM,Money counting machine etc
By size /capacity:
Capacity is therefore expressed in terms of the
volume of work that the computers can
handled, the speed of processing it and
functional unit of the CPU. The physical size of
a computer is not a good measure of the
computer. Computer according to capacity are
arranged in ascending order as fellows :
1)Microcontroller :Is a computer on a chip use
to control electronic devices. They are also
considered as a type of microcomputer since
they have microprocessor. The are sometimes
called hidden computers or embedded system
because they are inside a device.
1.It a single IC
2.Has RAM for data storage
3.Has RAM for program storage
4.Common with household appliances
2)Microcomputer :They are the smallest and
cheapest computer systems.Their memory
access time are about 100 nanoseconds and
handles 8bits,16bits or 32bits of word. They
are hardware components include system unit,
input /output devices and communication
its examples are desktop, note book PDA and
Tablet PC.They have a tiny sillicon chip in
3)Minicomputer :They are physically bigger
than micros and handles 32bits of words. Is a
class of multi user computers.They usually
used as server. eg IBM system and Workstation
in UNIX and Linux terminologies . Is larger
than the smallest single user computer.
4)Mainframe :Is large, powerful and expensive
general purpose computer. Is use principally
by large organizations such as large business,
universities, airlines, government agency etc, it
process 64bits of word. Examples, IBM 370,
IBM 3084 Cyber 170, NCR 8400.etc
5)Supper computer :Use primarily by
government and scientists. The largest and
most powerful of mainframe. It processes vast
amount of information in a very short time to
provide fast response to users. Also used in
weather services and airline reservations
systems. Examples cyber 205,Cray X-MP, Cray
2 and Cray 1 .
WHAT DOES COMPUTER DO?
Computers are found almost all over the
places with software packages available to
perform series of activities.
*The medical practitioners can use computer
to diagnose illness
*The account officer can use the computer to
prepare Pay Vouchers
*The police can use computer to check a
suspected car on a highway.
*The teachers teaches subject with sounds and
videos effects, graphics in the classroom using
*The soldier can use the computer to hit an
enemy target with precision.
*The sales person can use computer to record
the items bought by a customer.
The world now is becoming increasingly
difficult to find a professional field or career
or area of work that computers are not
applicable or use to enhance the work.
The computers do not have the ability to
decide how they will be used, who will use
them and when they will be used.
Computers do not have feelings and ability to
solve their own problems.
THE PROCESSING CIRCLE
The steps by which data is processed into
useful information is termed processing circle.
The five basic operations of the computer
-Storage operations and
Putting data into the computer using devices
such as, the keyboard, mouse, scanner,
joystick etc. Through these operation, the
computer accept data from outside world.
Simply,its manipulating data accepted by the
computer into meaningful use according to the
instruction given to it. The processing is done
by a device called central processing unit (CPU)
.The processing operations can be divided into
groups :thus Arithmetic and Logical operations.
The computer always output information in a
form that humans understand or like.Bringing
out or displaying processed data on the
computer screen and printing out the results
for the end user. Monitor, printer, loud
speaker, projector,etc are the devices that
carry out the operations.
A storage operation is perform when there is
the need to store information in the computer.
Information is kept inside the computer for
future use when produce by the computer and
is not needed immediately.
Devices responsible for the storage operation
are RAM, CD-ROM, Hard disks, floppy disks,
pen drive etc
Accessing e-mails, fax, online shopping etc
Devices use include modems, fax machines,
telephone lines etc
The three things that form the definition is
awareness, knowledge and lnteraction.
Is therefore defined as the awareness of values
of the computer, and having minimum
knowledge, capabilities and ability to interact
with the computer.
Becoming aware of the versatility, important
and pervasiveness of computers in our society
Learning what computers are and how they
knowing how to computers for some simple
Is the ability to use the knowledge acquired
through information and communications
technology to enhance teaching and learning in
classroom. ln other words, is the ability to
effectively use the knowledge of computers
and information to enhance or improve the
quality of teaching and learning.
Is the ability to incorporate technology
resources and technology base practices into
Computer curriculum may be defined as the
academic and non academic computer
activities that are planned for the school to
make the learners computer literate within a
given period of time at specific levels.
Computer literacy curriculum materials
1.The ICT syllabus
Common skills a computer literate should
2.Connecting a keyboard and mouse to their
3.Keyboarding and mouse manipulation
4.Insecting and removal of discs
5.Connecting and disconnecting of peripherals
Operating system skills
1.Opening, deleting, saving files and renaming
2.Selection of file for copying or removing
3.Creating folders or directories
4.Installing and running new software from CD
ROMs and Hard disks.
5.Uninstalling unwanted software packages
Application Package software skills
1.Know which program is appropriate for the
task at hand
2.Cutting and pasting text
3.Making documents very attractive formatting
4.Use word processor to write simple
reports,letters and memos etc
5.Creating tables and graphs etc
6.Listing and sorting records according to
1.Connecting a printer to the computer
2.Installing the printer’s device driver and
3.Knowing how to add paper to the printer
4.Knowing how to check and clear the print
5.Changing the ribbon cartridge and toner
when the need arises.
1.Using address books
4.Dealing with spam
5.Receiving, reading and replying to e-mails
6.Attaching files and opening attachments
7.Participating in chart rooms and discussion
Technology Integration in Education
These simply means using computer in the
development of education.
Barriers to technology integration in
1.Frequent power outage
2.Lack of computer hardware and software
3.Lack of fund to maintain the facilities
4.Lack of administrative support
5.Lack of qualified computer teachers to
handle the ICT programme
6.Lack of structure to use as computer labs.
IMPORTANT OF COMPUTER IN EDUCATION
Computers are used to develop Education in
various ways, These are few :
1.Schools use computer for teaching and
learning in the classroom
2.Both staff and students in colleges use
computers for research on the internet
3.Universities and Distance Learners use
computers for Distance learning purposes
4.ICT is now a subject taught at all levels of
5.Computers through the internet would make
students get interested in foreign cultures and
6.The use of computers will help educators in
mainstreaming the handicap into the public
Why are computers so powerful?
The things that make computer to be powerful
Computer can carry out billions of operations
in a single second. Very fast in executing
Capability to store huge volume of data /
information on a storage device for future use.
Thus very low failure rate and produce
Results are error free if inputs instructions are
Computer can do variety of works /things
It can be connected by communication device
such as modem to share data, instructions and
information. Easiest and quickest means of
transmitting data/information, ideas etc
COMPUTER COMPONENT 1
Computer itself refers to the system unit. All
other components connected to the system
unit are known as peripheral devices or
peripherals. The most common are the
monitor, keyboard and the mouse.
Software, also called program consists of a
series of related instructions that tells the
computer what to do or task to perform and
how to perform them. There are two types
1) System software
Is a set of program that coordinate the
hardware, software and other resources of the
computer system. it consists of four (4) main
1.The operating system
Operating system (O S) -Is the program that
act as intermediary between a user and the
computer hardware. Is the most important
system software. it automatically loaded when
the computer is put on.
Every operating system is design to serve 3
main objectives,thus Managing computer
resources, Providing User Interface and
classification of (O P)
1.Single user with single tasking -Is designed so
that the computer can do one thing at a
time.eg palm OS
2.Single user multitasking-It perform multi
task or activities at the same time.eg Unix,
It allows two or more users to run program at
the same time. These is in the case of supper
computers and mainframe.
It allows more than one program to run
concurrently. Playing music, working with the
word processor, spreadsheet as well as
searching the web all the same time.
Processing done by two or more computers or
processors link together to perform work
simultaneously. Support running a program on
more than one CPU.
ROLE OF OPERATING SYSTEM
2.Providing User Interface
3.Scheduling system request
5.Controlling and allocating memory.
Is a set of rules,instructions or tools that
enable the user of a computer to interact
effectively with the computer. Is also a the
user controllable display screen that allows
users to communicate or interact with the
Type of interfaces
They are two type of interface. These are
graphical user interface and command line
graphical user interface(GUI)
it provide the user with control options such
as buttons,menus, toolbars etc. It operate on
point and click mouse mechanism. It is user
Command line interface(CLI)
This interface is provided by the keyboard
only. it involves type and press enter key
mechanism. it is not user friendly.
role of the interface
1.system errors and other program errors are
reported to the user through pop-up menus
2.it makes shutting down or logging off of the
3.It ensure friendliness with the computer
Utilities are special programs designed to
service the computer system so as to perform
to it potential.
Microcomputers can not run without problems
Utilities enable the user to perform
maintenance tasks on the computer hardware
including the operating system and application
Is a software program that identifies, prevents
and eliminates computer viruses and other
malicious software programs called malware.
Preventing computer from anti virus
1.Updating your anti virus program regularly
2.Download files from virus free sources
3.Scan files on storage mediums before
opening them on your computer.
It a program or instructions that allows users
to make a copy of the entire disk or selected
files on the hard disk onto another storage
medium for safekeeping.
where to keep backups
1. On-sight backup >keep in the same place /
location as where the backup was made.
2.Off-sight backup > keep in different location
from where the backup was made.
Types of Backup methods
1. Full backup-it involves copying all the data
in the folders and files that are selected. it
should be perform frequently.
2. Differential backup -it contains all files that
have changed since the last full backup.
3. Incremental Backup-it stores all files that
have change since the last backup.
They are specialized programs that allows
devices such as mouse, keyboard and printer
to communicate with the rest of the computer
These are programs that convert the
programning instructions written by
programmers into a language that computers
understand and process.
Is a software designed to perform a specific
task for users. Popular application softwares
include spreadsheet, database,word processing
Types of application software
-Open source software
-Public domain software
*They are quick and easy to implement
*They are immediately available
*They are properly documental
*They are efficient in terms of speed, storage
-They might not meet the need of a particular
-They might be show in terms of execution.
Its simply stand for personal computer. A
typical PC consist of the the system unit,
monitor, keyboard and mouse.
The system unit
Is the box or case that contains or house the
computer’s main circuitry and storage devices.
it is the computer itself. It is sometimes called
chassis or system cabinet.
Components of the system unit
2.Power supply unit
8.PC slots and cards
12.CD-ROM or DVD-ROM drive etc
The motherboard consists of a flat board that
files one side of the case and contains
soldered, non removable components and
sockets,and slots for components that can be
removed.eg RAM chip. It defines the computer
limits of speed, memory, and expandability.
components of motherboard
+ISA/PCI/AGP bus slot
+ROM BIOS (flash ROM)
+CPU voltage regulator
+Battery, fan and heat sink
The electricity available from the wall outlet is
called Alternating Current (AC). But
microcomputers run on Direct Current (DC).
The power supply unit is a device that converts
power from AC to lower voltage DC to run the
computer. The power supply unit is a designed
to blow when too much power is supplied into
it to ensure that the rest of the system is not
THE CENTRAL PROCESSING UNIT (CPU)
The CPU is also called the Processor or
microprocessor, is the brain or engine of the
computer. Is the part of the computer in
which arithmetic and logical operations are
performed and instructions are decoded and
executed. The CPU consist of the control unit
( CU) and the arithmetic and logical unit ( ALU)
#The CU control and coordinate the work of
the CPU itself and tells the rest of the
computer components how to carry out
program instructions. In actual fact, it direct
the step by step operations of the entire
#Arithmetic and logical unit (ALU),Is the
portion of the CPU where arithmetic and
logical operations are performed. Arithmetic
operators such as
1. addition +
2. subtraction –
3. multiplication *
THE MACHINE CYCLE
The system clock synchronizes the computer’s
operations. The is the series of operations
involved in execution of a single, machine level
instructions. The machine circle is carried out
in four steps. These are
Fetching-is the process of obtaining a
program instructions or data item from
Decoding -is the process of transacting the
instructions into commands the computer
Executing-is the process of carrying out the
Storage -is the process of writing the results to
The control unit is responsible for the four
steps involved in the machine cycle.
Is the internal storage area in the computer.
Storage on the other hand is memory that
exist on tapes and disks. A computer uses
memory to store data and information.
There are 3 types of memory chips, these are
1.Random Access Memory (RAM)
2.Read Only Memory (ROM)
3.Complementary Metal Oxide Semiconductors
It is call the primary memory.
It is volatile
1.Hold data that have been processed.
2.Hold data for processing .
3.Hold instructions for processing data.
1.Static Random Access Memory (SRAM)
2.Dynamic Random Access Memory (DRAM)
Is also called firm ware because they have
program built in them permanently. It is a
secondary memory. Is non volatile. it also
contains the BIOS .
1.Programmable Read Only Memory (PROM)
2.Erasable Programmable Read Only Memory
3.Electronically Erasable Programmable Read
Only Memory (EEPROM)
It contains essential information required
every time the computer system is turned
on.It is powered by a battery. It can store
information that is permanent but changeable.
Its the pathway that connects the various
system components within the computer.
1.Input/Out bus-Connects the processor to the
2.System Bus-Allows the processor to
communicate with peripherals that use are
either inserted into the expansion slots of the
motherboard or connected to a port attached
to the motherboard.
classification of system buses
Is a connecting socket on the outside of the
1.Accelerated graphics ports
2.Universal serial bus ports
4.Fire wire ports
Is a method of protecting information,
computer programs, and other computer
system assets. Is also keeping the computer
system safe from criminals,natural hazard and
other threat in other to protect information
kept on the computer.
computer criminal-Is a person who use
special knowledge of computer technology to
carry out illegal activities on the computer.
eg.Hackers, crackers, terrorist etc
Computer crimes -These take various forms
including the denial of service attack,theft,
Internet scam, malicious programs and data
The most important types of malicious
viruses, worms, trojan horses.
1.(PC) Personal Computer
2.(ICT) Information Communication Technology
3.(USB) Universal Serial Bus
4.(ASCII) American Standard Code for
5.(DC) Direct Current
6.(AC) Alternating Current
7.(EBCDIC) Extended Binary Coded Decimal
8.(POST) Power On Self Test
9.(CD-R) Compact Disk Recordable
10.(CD-RW) Compact Disk Rewritable
11.(DVD) Digital Versatile Disk
12.(DVD-R) Digital Video Disk Recordable
13.(DVD-RW) Digital Video Disk Rewritable
14.(CLI) Command Line Interface
15.(GUI) Graphical User Interface
16.(ALU) Arithmetic Logic Unit
17.(AGP) Accelerated Graphic Port
18.(IBM) International Business Machine
20.(HD) Hard Disk
21.(WORM) Write Once Read Many times
25.(PDA) Personal Digital Assistants.
They measures to protect computer security.
1.Backing up data
4.Restricting access to computer system.