Define computer terminologies
Computer: This is an
electronic device that accepts data, process, store, retrieve and gives out
information.
Data: This is a raw fact
of a given subject e.g. (1+1, a+b, a²)
Information: It is the
data which has been processed or end result obtained after process.
Bit: This is the
smallest unit of information a computer can process.
A bit
is a dot(.)
Byte: It’s a collection
of 8bits.
A byte can be a
character A, B,2,8 etc.
Electronic device: It’s
a machine which requires power to operate.
Process: state of
converting data into information.
Retrieve: make the data
available when needed/recover information stored.
2.FACTORS TO CONSIDER
WHEN BUYING A COMPUTER.
·
Cost
·
Size of memory egg
256mb,512mb,1gb,2gb
·
Speed of the processor
egg P1, P2, P3, P4 GHZ
·
CD-ROM, DVD ROM.
·
Quality and Durability
upgradability Technology wise, period system can last.
3.ADVANTAGES AND
DISADVANTAGES OF A COMPUTER
i. Advantages of a
computer
1. Stores large amount of information in a limited
space.
2. Speed-performs task very fast compared to man
effort
3. Consistency-gives the same result given the same
instructions
4. Secrecy-Information is fairly protected if the
computer system is well managed(password)
5. Versatility-can do the same thing over and over
again without getting worn-out
6. Computer can work under hostile environment egg
Volcanic eruptions.
ii. Disadvantages of
a computer
1. They are expensive to acquire and maintain
2. Need expertise, which is expensive to hire and
maintain
3. Computers are health hazards i.e., Eye problems
4. They cut down employment opportunities to those
not skilled.
5. Can lead to lose of information if not well
managed.
4. EXAMPLE OF FIELDS WHERE COMPUTERS ARE USED.
Industry and commerce.
Keeping track of orders
and bills transactions in companies and industries
Used in defining new
products or services and to carry day to day operations
communication sectors.
Digital communication
worldwide is done through computers, unlike analogue communication using the
telephoning systems
E-mail communication
Electronic file transfer
where communication is done through internet.
Education and Reference
Computers incorporates
database that are useful in managing education resources.
Internet provides
reference materials for learning
Computer systems are
used in libraries for storage of information and retrieval.
Entertainment sectors
Computers support high
quality pictures which are stored in communication worldwide etc.
Computers support music
files using high speed and efficient digital storage devices such as DVDs, CDs
etc.
Games are also supported
by computers as a source of entertainment at homes and other special places.
Health care and
Medicine.
Keep patient records and
medical Insurance data
Computers perform
medical diagnosis.
Used in monitoring
patient at I.C.U(Intensive Care Unit).
Police and Defense
Computer are nowadays used
greatly in fighting crimes through computer forensic
Police are able to enter
fingerprints to database which are automatically analyzed by a computer.
In defense computers are
used in electronic news gathering, efficient communications, detection and tracking
of terrorism, radar systems in Airports.
Computers are also used
in warning and guiding missile systems.
THE COMPUTER SYSTEM
Refers to a system of interconnected computers device that share a
central storage system and other peripheral devices such as printers, scanners
or routers in order to communicate.
COMPONENTS OF A COMPUTER SYSTEM.
The
basic components of the computer are:
HARDWARES
SOFTWARES
HUMANWARE/ORGWARE
FIRMWARE
1.HARDWARES
These are all the physical
and tangible parts of the computer system.
They include the
following categories of hardware.
Input devices.
These are devices that
allows the user to enter data into the computer system.
They include-keyboard,
mouse, keyboard, mouse, Digital cameras,
Joysticks-used in
playing games
Scanners-Captures
graphical texts and drawings into the computer system.
Other examples of manual
input devices are:
Remote control, Touch
screen, Calculator (numeric keypad), Microphone,
Graphics Tablet, Webcams
(used in computers)
Output Devices
These are the devices
used to provide the user with the results after data has been processed.
Output devices they
include:
Monitor/screen/VDU
(Visual Display Unit). Information displayed on the screen prior printing is
called softcopy
Printers. These are the
output devices used to output data in hardcopy (touchable data on paper)
or print out.
Plotters. A plotter is a
graphic printer that draw images with ink pens.
They are also used in printing graphics on large
paper sizes and full-sizes
engineering and architectural drawings, produce Maps, Charts etc.
Speakers-produce
information in form of sounds.
c)Input/Output
devices
These are devices that
work both as input/output devices e.g. You can have a printer that can also be
used as a scanner.
Touch screen
Smart phones
Tablet computers.
d)Central
Processing Unit (CPU)
It’s the heart and brain
of a computer
The CPU consists of 1 or
more Integrated Circuits
The CPU has 3 Main parts
Control Unit (C.U)
Arithmetic logic Unit
(A.L.U)
Main Memory Unit (MMU)
i) Arithmetic Logic Unit (ALU)
Performs
arithmetic calculations such as (*, +, /&-)
ii)Control Unit (CU)
It
controls, supervises and oversees all the activities taking place in the
computer system.
It
also interprets the instructions and issues signals so that the hardware
excites them as requested.
iii)Main
Memory
There
are Two main type of Memory in a microcomputer i.e.
i)RAM (Random Access Memory)
The name Random Access
means that the information in any area of the RAM can be read or accessed in
the same amount of time randomly using a technique called algorithm generated
address/mathematical procedure.
Characteristics of RAM
Its volatile-when power
goes off without saving your work you lose all the data.
Data stored in RAM are
Temporarily
You can read and write
on the RAM
ii)ROM (Read Only Memory)
The contents of ROM
cannot be altered
The contents of this memory can be retrieved/read and cannot be
written on it thus you use the contents the way they are because it’s designed
by the manufacturers of that product.
Characteristics of ROM
Its non-volatile: its
contents remain intact even when the power goes off.
Stores data
permanent.ie.its contents can be read but cannot be written during normal
computer operations. The same contents are used when computer is booting.
E) OTHER STORAGE DEVICES INCLUDE:
NB/Primary storage device/internal storage is the HARDDISK-inside
the system unit.
Secondary storage/Auxiliary storage are: Auxiliary CARD, Google
drive, sky drives etc.
F) Communication Devices e.g., MODEM
Modulator Demodulator-changes analogue signal to Digital signals
and vice versa.
2. SOFTWARES
These
are programs that makes the computer hardware’s to function.
A
program is a set of instructions in a language known to a computer telling it
what to do.
We’ve
two types of Software i.e.
System software
Application software
SYSTEM SOFTWARE
These are programs that
deal with solving the problems of computer Hardware’s.
These are Hardware
oriented programs.
They are farther divided
into:
Operating System
Language Translators
Programing languages
Utility Programs
Operating System
It’s a program that
helps to control and manage the operations of the computer system.
Operating system acts as
an interface between the user and the computer hardware and other software.
It’s the most important
program in the machine.
Without the operating
system the computer cannot function.
FUNCTIONS OF OPERATING
SYSTEM (O.S)
Process management-The
oz.’s keeps track of all activities taking place in the machine.
Resource Management-The
oz.’s allocates system activities to the CPU, Main memory, input/output devices
etc.
Data management –The
oz.’s handles the movement of data between the components of the system.
Error detection and
correction-The oz.’s detects errors caused by other programs, hardware and
issues a suggestion on how to rectify them.
TYPES OF OPERATING SYSTEM
Single user single
program operating system e.g., MS DOS
Multi-program
multi-tasking oz.’s e.g., Windows
Examples of operating
system in the market are:
Microsoft windows (its
Versions are, windows Pindos 7, windows 8 etc.)
Ubuntu (open source)
MS Dos etc.
ii) Language Translators
It’s a program that
translates human understandable language to machine code language and vice
versa so that communication can take place.
There are three types of
language translators i.e.
Assemblers
Compilers
Interpreters
iii)Programing languages
These are programs that
are used to develop other useful programs.
For example, C++, JAVA,
VISUAL BASIC etc.
iv)Utility Programs
It’s
a program that provides a certain unique services to the computer. For example:
scan discant-virus
Application software
These
are programs that are used to solve user problems
They
are farther divided into
User Defined Program
Application packages
User Defined Program
These are programs
that are used to solve specific user problems.
They can also be
referred to as Tailor made programs Geoff-shelf programs
Application packages
They are classified
into:
Word processors
Spreadsheet
Database programs
Accounting packages
Communication programs
Presentation programs
Engineering and Architectural
programs.
3.HUMANWARE/ORGWARE/LIVEWARE
These are the people who work with computers.
They are farther divided
into 5 Categories:
Users
Designers
Developers
Technician
IT security personnel.
MODULE
TWO: KEYBOARD AND KEYBOARDING PROFILE
Objectives:
KEYBOARD-
It
is an input device used to feed data into the computer.
The
keyboard has several keys. These keys differ from each other.
TYPES OF KEYBOARD
Mechanical key switch
keyboard
They are mostly used with desktop computers and they can also be
used with laptops
These keyboard works by use of individual switch for each
keyboard.
Capacitive keyboard
These keyboards are used
in laptop computers, they take up less space.
NB/keyboard are divided
into several parts i.e.
FUNCTION KEY.
These keys range from
F1-F12.These are multi-purpose keys.
This means the function
of each key change from one program to another.
e.g., f1-help,
f4-refresh, f7-spelling and grammar check.etc.
ALPHANUMERIC KEYS.
These are keys
containing e.g., as well as spacebar.
Standard keyboard uses
QWERTY layout.
MODIFIER KEYS/SPECIAL
KEYS
They include ALT,
CTRL&SHIFT.
These are special keys
on a computer keyboard that modifies the normal action of another key when
pressed in combination.for example.
ALT+F4-exit/close active
window running.
CTRL+S-Saving changes to
a document.
Ctrl+p- print
Ctrl+v-paste
Ctrl+x-cut
Ctrl+c-copy
Ctrl+esc-open start menu
CTRL+Z-undo last action
Ctrl+y-redo last action.
Ctrl+d-display fonts
Ctrl+n-new document
Ctrl+o-open a document
Ctrrl+e-align center
Ctrl+r-align right
Ctrrl+l-align left
Ctrl+j-justify text.
Ctrl+a-select all
Ctrl+u-underline.
Ctrl+i-italics
Ctrl+b-bold
EDITING KEYS
They
include-Backspace,Insert&Delete keys.They enable additional control over a
document.
SYSTEM KEYS
Print screen,esc.
Print screen is used to
capture the screen.
Esc key is used to
initiate escape signals.
6.LOCK KEYS
They include-Num lock,
Cap’s lock and scroll locks.
These keys lock part of
the keyboard depending on the selected settings.
7.TABS KEY
It’s used to create an
indent.
8.WINDOWS KEY
They
are used to display a start menu and a shortcut menu for windows program.
9.NAVIGATION KEYS/CURSOR MOVEMENT KEYS/ARROW KEYS.
They
are marked with arrows and control the cursor movement.
The
cursor is the blinking line on the screen, which helps in typing text.
The
Home screen, which up, page down is part of navigation keys.
10.NUMERIC KEYPAD
These
are keypad on the right hand side of the keyboard.
They
range from 0-9.
We
use these keys to enter data in form of numbers, perform calculations and
controlling the movement of cursor especially if the num lock is activated.
MICROSOFT WINDOWS BASICS
WINDOWS DESKTOP
The
desktop is your work area on which program and files icons are located. It is
basically a workspace where you can access everything you need to operate your
computer, such as system components, applications, the Internet, etc
Parts of the Desktop
1. Start
button: The start button allows you to open menus and start applications.
2. Taskbar: It
is primarily used to switch between open windows and applications.
3. Icons: These
are pictorial representations of applications, files, folders and other parts
of the operating system.
4. My
Computer: The “My Computer” icon provides access to the resources on your
computer e.g. Disk drives such as Drive C
5. Internet
Explorer: The internet explorer icon launches the Internet Explorer
browser.
6. My
Network Places: If you are working on a network, this displays all of the
computers on the network.
7. System
Tray: The part of the taskbar that holds the clock, volume control, and
icons for other utilities that runs in the background of your system.
8. Recycle
Bin: This is a temporary storage location for deleted files and folders.
PARTS OF AN APPLICATION WINDOW
Title
Bar: This is a bar across the top of the window that displays the name of
the current application program or task.
Menu
Bar: Menu bar provides a list of commands that can be used to manipulate a
task. E.g. Insert, Page Layout, View, etc.
Toolbars: These
are buttons arranged in a row that are shortcuts to menu commands.
Work
Area: This is where you organize your work within a program.
Status
Bar: Displays information about the program e.g. page number, number of
words, etc.
Scroll
Buttons: They are used to move the window up/down or left/right in order
to view the hidden parts of the window.
Minimize
button: It reduces a window to appear as a button on the taskbar.
The
restore/maximize button: It stretches the window to cover the entire
desktop or restores it to its original size.
Close
button: It is used to exit an application
CHANGING THE DESKTOP BACKGROUND
1. Click Start button.
2. Click Control
Panel.
3. Click Appearance
& Personalization.
4. Click Change
desktop background.
5. Choose
the background you want to set.
6. Click Save
Changes.
SCREENSAVER
A
screensaver is a computer program that blanks the screen or fills it with
moving images or patterns when the computer is not in use.
Importance of a Screensaver
1. Screensavers
increase your privacy, as well as security. If you are working with
confidential data you wouldn’t want others to see, the screensaver will
eventually cover this data on your screen up after a certain amount of time.
2. A
screensaver is used for entertainment purposes.
CREATING A SCREENSAVER
A. SETTING THE
IMAGE
1. Click Start button
2. Click Control
Panel.
3. Click Appearance
and Personalization.
4. Under Personalization, click Change
screen saver.
5. Under
screensaver area, select the screensaver required e.g. Bubbles, Mystify,
Photos, Ribbons, etc.
6. Click OK.
B. SETTING
A 3-D TEXT SCREENSAVER
1. Click Start button
2. Click Control
Panel.
3. Click Appearance
and Personalization.
4. Under Personalization, click Change
screen saver.
5. Under
screensaver area, select 3-D Text.
6. Click Settings.
7. In
the Custom Text area, type your name/ text.
8. Set
the Rotation Type, Colour, Rotation Speed and Size.
9. Click OK.
MODULE
THREE:MS DOS(Microsoft Disk Operating system)
Objctives:
Ms Dos –It’s a program
that:
Controls the computer
system
Links the user with the
computer
Controls the computer
resources and the pheripheral devices.
Rules governing naming of files.
Filenames are not case
sensitive.
Maximum length allowed for
a filename is 8 characters.
Maximum length allowed
for the extension to a file name is 3 characters.
The filename and
extension are separated by a period(.)
Punctuation
marks(‘,?>”!{}[] and spaces are not allowed because they’ve special meaning
in Ms Dos.
How does Ms Dos works?
Ms Dos works by use of
commands
It’s a single- user
,single-tasking operating system(ie. It can run only a single application at a
time)
It does not support
multi-media ie.it does not support graphics and sounds.
It uses keyboard to type
commands.
Ms Dos works in two type of commands:
Internal commands
External commands
These commands are entered on the Ms Dos prompt eg.C:\>or
A:\>
Internal commands
These commands are loaded automatically when the computer starts.
Examples of internal commands are:
Time
Date
Ver
Vol
Dir
Cls (clear screen)
to create space to type new content.
Copy con
Type
Copy
MD (make Directory)
CD (change
Directory)
CD\ (used to
change to the root Directory)
CD.. (used to move back
one level above the current Directory)
External commands
These commands require
special type of files to be executed.
They
are loaded into the memory only when called, they are then found in separate
files on Hard Disk or Floppy Disk,so that they don’t typically consume valuable
memory space.
Examples
of External commands:
Tree
Edit
Label
Working with files and Directories:
What
is a file?
A
file is the smallest unit of storage.The name given to a file should be related
to the content it contains.
Elements of a file: A file consists of:
File name
Period
Extension
Date
Time
Bytes
A file name is that name given to the file.A file name
should not exceed 8 characters.ie.
Command.com
File
name
Extension.
A period separates the file name and extension(.)
An extension identifies the type of files and should not exceed 3
characters.
NB:Extension is not a must.(some files do not have extension).
EXAMPLE OF EXTENSIONS
Com-These are command
files that control the programs
Sys –system files
TXT-text files
DOC-Document files
Exe-These are excutable
files that make program run.
The
date indicate when the file was created (current date of the computer).
The
time indicate the time when the file was created.
The
bytes indicate the number of characters in a file. A byte is a character.
Ms Dos prompt
Ms
Dos prompt indicates that Ms Dos are ready to accept commands.
C:\>
A:\>
WORKING WITH COMMANDS
1.DIR
Dir
command displays/list all files in a directory or drive.shows
Filename
-Date
Extension
-Time
Bytes
Syntax:
C:\>DIR [ENTER]
2.TIME
Time
command displays the current time and enables you to enter new time.
Syntax:
C:\>TIME [ENTER]
3.DATE
The
date command shows the date when the file was created or modified and enables
you to enter new date.
Syntax:C:\>DATE
[ENTER]
4.VER
Shows
the Ms Dos Version
Syntax:C:\>VER
[ENTER]
5.VOL
Vol
command displays the volume label of a disk.
Syntax:C:\>VOL
[ENTER]
6.COPY
CON
This
creates a file in Ms Dos.
Syntax:C:\>COPY
CON
This
creates a file in Ms Dos.
Syntax:C:\>COPY
CON {FILENAME} [ENTER]
“Type
the text you want” then to save your text file hold down the CTRL+Z OR press F6
(function key)
Then
you will see 1file copied.
7.TYPE
The
type command is used to see the content of a file.
Syntax:C:\>TYPE
{FILENAME} [NTER]
CREATING FILES
Files
can be created in word processors,Database and other packages,also they can be
created directly from Ms Dos commands. We have two ways of creating files:
Copy con
Edit
Copy con
Type the command copy con
followed by filename period extension then press enter.
Type the content of the
file
Save or close by
pressing F6 or CTRL+Z
Press enter key. You
will see 1file copied.
Syntax:copy con {filename}<enter>
Type the content……………………………………………………………………….
…………………………………………………………………………………………………………
………………………………………………….F6 or Ctrl+z<enter>
Edit
This
is an advanced way of creating files in Ms Dos using the full screen editor
window known as Ms Dos editor,which allows you to edit,save and print.
Syntax:c:\>edit
{filename}<enter>
NB: To save your work in Ms
Dos editor press ALT key on the keyboard,then press F,then S.
To
exit the ms dos editor window press ALT,then F, and then X.
8.COPY.
This
command helps to ake a duplicate of a file.It copies file contents from a
source file to a destination file.
To
copy the contents of a file to a new file.
Syntax:C:\>COPY
(source filename) (destination filename)<enter>
MODULE FOUR:MS WINDOWS
Objctives:
Microsoft Windows is an
operating system developed by Microsoft corporation.
Windows like any other
operating system it links the user with the system,manages computer resources
and controls how computer works.
Windows is a Graphical
User Interface(GUI) operating system.
Graphical User Interface,is
a type of interface that allows the user and the computer to communicate by use
of Icons(pictures).
Windows has an
outstanding features known as WIMP(windows,Icons,Menus &Pull down tabs)
Desktop properties:These
are features found on the desktop when you open a computer.
Example of Desktop
properties:
Icons
Taskbar
Icon-is
a small pictogram used as a graphical user interface.
Taskbar-It’s
found at the bottom of a screen and it is divided into 3 parts.
Start button-It contains
start menu commands.
Task plain-It displays
the name of the running program.
System tray/Notification
area-It displays time,date and protection status of a computer.
Main computer Icons are:
My document-This is used
to store documents and files within a computer.
My computer-it displays
features of a computer e.g.Size of the memory,drives installed etc.
My network places-It shows
shortcuts to websites and network computers.
Recycle bin-It contains
deleted files and folders(documents)which can be restored.
Changing the Background of a computer.
Right click on the blank
space on the desktop
Select properties
Click desktop
Choose background
of your own choice.
Click apply then ok.
Applying the screensaver
Right click on the blank
space on the desktop
Select properties
Click screensaver
Choose screensaver of
your choice
Click apply then ok.
Resetting date and time.
Double click at the
system tray where the time is being displayed.
In the part of month
choose the correct months.
In the part of date
choose the correct date.
In time set the correct
time and click apply then ok.
Creating Folders
A
folder is a logical container that we can use to organize files.
You
can create sub-folders under the main folder.
A
default folder in a harddisk is my documents.
How to create a folder.
Right click on the blank
surface on the desktop
Select new
Click on it type name of
your choice then press Enter.
How to Rename a folder.
Right click on the
folder which you want to rename.
Type your desired name
and press Enter.
How to Delete a folder.
Right click the folder you
want to delete
Then select delete.
Creating Files
A
file is an electronic document created in any given application.
It’s
used to store related documents.
How to create a file.
Right click on the blank
part of the screen.
Select new then point at
text document and click
Type the file name then
press Enter.
ACCESSORIES.
These
are the programmes that come together with the operating system.
They
include:
Calculator
Notepad
Wordpad
Ms paint
System tools etc.
Calculator
Calculator are programmes that are used to perform simple and
complex calculations.
How to Start a Calculator.
Click the Start button
Point on Run and type
“Calc”
Click ok.
Notepad/wordpad
This is a word processor program that we use to type,edit,format,spelling
check and printing of professional documents like:
Letters
Reports
Minutes etc.
Procedure of starting
wordpad.
Click the start button
Point to all programs
Select accessories
Then point at wordpad.
Ms paint
Click on start button
Click programmes
Click accessories
Select Ms paint
Using the tools make a
drawings of your own choice.
After drawing save your
work in an appropriate location eg.
Desktop, my documents, my computer.
SAVING A DOCUMENT
Click on file menu
Then select “save as”
From the resulting
box select the location of the file i.e. either
My documents
Folder or Removable
media.
Type the file name then
click save.
MODULE FIVE:MS WORD (Microsoft word processor).
Objectives:
1. Define word
processor.
2. Give examples of word
processor.
3. Discuss uses of word
processor.
4. Starting Ms word and
Discuss parts of word window.
5. Typing a document
6. Save a document in a
folder, Flash disk, or on the Desktop.
7. Saving a document with
a password.
8. Editing texts: a)Copy
and paste
b)cut and paste
c)Find and Replace
d)spelling and grammar check
e)Thesaurus.
9. Formatting text.
10. Inserting Options
11. Tables
12. Mail Merge.
1.Define word processor.
It is a program that we
use to type,edit,format,spelling check and printing of professional documents
like: Letters, Repports,Minutes etc.
2.Examples of word
processor.
Ms word
Notepad
Wordpad
Word perfect
Word star etc.
3.Uses of Ms word
Used for preparing
documents like: Books, letters, Minutes, Newsletters, Magazines, Preparing
charts, tables, Mail Merging Letters etc.
4.Starting Ms word
Click on the start
button
Click on programmes
Select Microsoft Office
Then select Ms word
2007.
Or
Press and hold down
Windows key on the keyboard
On the Run box displayed
type “winword”
Then press enter or
click ok.
5.Parts of word window.
Title bar
Control button
Typing area(working
area)
Office button
Rullers
Scroll bar and scroll
buttons.
Dialogue box Launcher.
Ribbon/groups tab.
Windows border
Zoom level area.
Quick access tool bar.
6.Saving a document
We use “save as” command
to save a document for the first time or give file a new name.
“Save” command is used
to save changes made on an existing document.
7.Saving a document with
a password
To protect a document
against an authorized access save a document with a password.i.e
Click on File
menu/Office button and select save as, then select general Options then input
your password and click save.
8.Editing texts
a) Copy and
paste-Enables you to make a duplicate/copy of information/text document
b) Cut and Paste-Enables
you to delete the highlighted texts or original information and then retain new
information.
c) Find and Replace-Enables
you to replace a certain word with another.
d) Thesaurus-This
is a tool that provides a synonyms.
e) Spelling and
grammar check-Enables you to recognize any spelling error or grammatical
errors.
9.FORMATTING TEXT.
This
is a method used to enhance the appearance of a document.This can be done
through:
a).Font type, Size,
colour, underline, Italics, Bold etc
b).Change Case
c).Tabs (you tab before
you type a text at the beginning of a sentence.
d).Columns
e).Bullets and
Numbering.
f).Indenting, line
spacing.
g). Alignment
ie.Right,Left,Centre,Justify.
h). Borders and shading,
Superscript & subscript.
NB:For you to apply any
of these formatting components you have to highlight your document/ word first.
10.INSERTING OPTIONS.
Word Art
Clip Art
Smart Art
Shapes
Charts
Headers and footers
Symbols
Cover page
Page numbers
Drop Cap
Date and Time
11.TABLES
Insert tables
Enter text in a table
Add and Remove rows and
columns
Performing Calculations
in a table.
Merging cells
12.Mail merge a letter.
INTERNET
It
is a large network of networks that covers the whole world and enables millions
of computers from different organizations and people to communicate globally.
Importance of Internet
The
importance of internet can be seen through its contribution to:-
a) Research
activities
b) News and
information dissemination.
c) Leisure
d) Communication.
e) Business
Transactions, etc.
Requirements for Internet Connectivity
(a) Telecommunication
facilities
Internet
relies on telecommunication facilities like telephone lines, telephone exchange
station and satellite transmission in order to cover the whole world.
(b) Modem
(Modulator-Demodulator)
It
is a special digital to analog interface card that changes data from digital to
analog so as to be transmitted on telephone lines and on receiving end the data
is changed from analog to digital for the computer to understand.
(c) Internet Service
Providers (ISP’s)
These
are companies that offer internet services to end users. They provide the
Internet services to end users at a fee.
Examples
of ISP in Kenya include:
1. Liquid
Telecom
2. Access
Kenya
3. Zuku
4. Faiba
5. Telkom
Kenya
6. Safaricom
(d) Internet Software
Internet
software help facilitate your access to the Internet. To achieve communication
between computers special software called Protocol is needed.
INTERNET SERVICES
1. E-mail
This
is the exchange of electronic letters, data and graphics on the internet.
2. Electronic
Learning (E-learning)
This
is learning through interaction with special programs on the computer.
3. Electronic
Commerce (e-commerce)
It
refers to buying and selling of goods and services over the internet.
4. World
Wide Web (WWW)
In
order to connect a network to the internet, the local area network needs an
internet server. This server is given the name world wide web (www) and has all
the information which others on the internet access.
ACCESSING THE INTERNET
Software applications
that enable the user to access information on the internet are called Web
Browsers. Examples of web browsers include:
·
Mozilla Firefox
·
Netscape
Navigator
·
Google
Chrome
·
Opera
·
Internet Explorer
·
Safari
I Login/ Sign In
To
access a website, type the full address of the website on the address
bar, then press the enter key.
Surf/ Browse
Surfing/
Browsing is the process of accessing Internet resources like web pages and
websites.
Hyperlinks
A
hyperlink is a text or picture on an electronic document that causes other web
pages to open when the link is clicked.
Search Engine
This
is a program that searches documents for specified keywords and returns a list
of the documents where the keywords were found. Examples of search engines
include: Google, Yahoo, Bing, Ask, WebCrawler, etc.
Downloading
This
refers to the process of transferring information from the internet to a local
storage e.g. a computer, flash disk, etc.
Uploading
Refers
to the process of transferring a file /files from your computer to the
Internet.
ELECTRONIC MAIL (E-MAIL)
Electronic
mail refers to the sending and receiving of electronic letters and documents on
the internet.
E-MAIL SOFTWARE
E-mail
software falls under communication software that are designed to help the user
to read and send individual text documents on the internet so long as the
sender and receiver have an e-mail address. Examples of e-mail software
include: Gmail, yahoo, hotmail, outlook express, thunderbird, etc.
E-MAIL FACILITIES
1. MAILS
a) Checking
Mail
In
order to check mail the user has to open the e-mail account by providing the
correct username andpassword. In e-mail account, click
the Inbox command to view a link list of all received mails.
b) Compose a
Mail
Composing
implies writing. To compose a message, click the Compose command.
c) Send
Mail
To
send mail, type the correct e-mail address of the recipient, and then
click Send command.
d) Forward
Mail
A
received mail can be forwarded to another recipient. After reading, click
the Forward command and then provide the address of the recipient.
2. FILE
ATTACHMENT
E-mail
software enables a person to attach other files like pictures, music, movie
clips, etc to an e-mail for sharing with others before sending. The source of
attached files can be from the hard disk or other storage devices.
3. ON-
LINE MEETING
It
is possible to hold an on-line meeting with people by sending mails to them
e.g. on-line interviews may involve a person sending electronic mail composed
of interview questions to a recipient who can read and answer back.
4. TELEPHONE
MESSAGES
Wireless
Access Protocol (WAP) makes it possible to send e-mail to a mobile handset and
a mobile message to e-mail account.
5. CONTACT
MANAGEMENT
Most
mail programs allow the user to develop an address book which holds contact
information like e-mail address of different people.
E-MAIL ADDRESS FORMAT
A
typical e-mail address would look like this:murimi@pctechkenya.com
murimi is the username and is usually
created by the user during e-mail account registration.
@
is the symbol for “at” which separates the user name from the rest of the
address.
Pctechkenya.com is the name of the host computer in the
network i.e. the computer on which the e-mail account is hosted.
Com identifies
the type of organization offering a particular service(s) and is called
the domain, meaning it is a commercial institution.
OTHER COMMONLY USED DOMAINS INCLUDE:
|
DOMAIN
|
TYPE
|
|
.edu
|
Educational
Institution
|
|
.gov
|
Government
Institution
|
|
.org
|
Non- profit making
organization
|
|
.mil
|
Military
organization
|
|
.co
|
Commercial
Institution
|
|
.net
|
An institution or
organization providing networking services
|
|
.ac
|
An academic
institution
|
E-MAIL COMPOSE WINDOW
A
typical e-mail compose window has three basic elements:
1. HEADER: The
e-mail header is made up of the following parts:
(a) Addresses of the
Recipients: The e-mail recipients can be more than one.
(b) Subject: Presents
the topic of the message.
(c) Attachment: Files
attached from other programs such as word processors and spreadsheets.
2. MESSAGE: This
is the content of the email. It is typically short and to the point. It may
include text and graphics.
3. SIGNATURE: The
signature provides additional information about the sender such as full name,
address and telephone number.
ATTACHING FILES INTO AN E-MAIL
1. Click
the Attachment button on the toolbar.
2. In
the Dialog box that appears, select the file/ files to attach.
3. Click Attach button
to attach the files.
COMPUTER VIRUS
“A computer virus is a program that
may disturb the normal working of a computer system”. Virus attaches
itself to files stored on floppy disks, USBs, email attachments and hard disks.
A file containing a virus is called infected file. If this file is copied to a
computer, virus is also copied to the computer.
Activation of Virus
When the computer virus starts
working, it is called the activation of virus. A virus normally runs all the
time in the computer. Different viruses are activated in different ways.
Computer viruses cause billions of dollars’ worth of economic damage each year,
due to causing systems failure, wasting computer resources, corrupting data,
increasing maintenance costs, etc”.
Damages caused by virus
Computer virus cannot damage
computer hardware. IT may cause many damages to a computer system. A virus can:
A computer virus can damage data or
software on the computer.
It can delete some or all files on
the computer system.
It can destroy all the data by
formatting hard drive.
It may display a political or false
message very few times.
Causes of Computer Virus
The following are the main causes of
a Computer Virus.
1. Infected
Flash Drives or Disks
Flash drives and disks are the main
cause of spreading viruses. Flash drives and disks are used to transfer data
from one computer to other. A virus can also be copied from one computer to
other when the user copies infected files using flash drives and disks.
2. Email
Attachments
Most of the viruses spread through
emails. Email attachment is a file that is sent along with an email. An email
may contain an infected file attachment. Virus can spread if the users opens
and downloads an email attachment. It may harm the computer when it is
activated. It may destroy files on the hard disk or may send the virus
automatically to all email addresses saved in the address book.
3. Infected
/ Pornography websites
Thousands of insecure websites can
infect computer with viruses. Most of the websites with pornographic materials
are infected, so by visiting these websites the user’s computer also gets infected
by virus. These websites are developed to spread viruses or other unethical
material. The virus is transferred to the user’s computer when this material is
downloaded. These websites may access the computer automatically when the users
visit them.
4. Networks
Virus can spread if an infected
computer is connected to a network. The internet is an example of such network.
When a user downloads a file infected with virus from the internet, the virus
is copied to the computer. It may infect the files stored on the computer.
5. Pirated
Software
An illegal copy of software is
called pirated software. Virus can spread if user installs pirated software
that contains a virus.
How to protect your computer
A computer system can be protected
from virus by following these precautions.
1. The
latest and updated version of Anti-Virus and firewall should be installed on
the computer.
2. The
Anti-Virus software must be upgraded regularly.
3. USB
drives should be scanned for viruses, and should not be used on infected
computers.
4. Junk
or unknown emails should not be opened and must be deleted straightaway.
5. Unauthorized
or pirated software should not be installed on the computer.
6. An
important way of protection against virus is the use of back up of data. The
backup is used if the virus deletes data or modifies it. So, back-up your data
on regular basis. There is some great software that can back up your data
automatically.
7. Freeware
and shareware software from the internet normally contain viruses. It is
important to check the software before using them.
8. Your
best protection is your common sense. Never click on suspicious links, never
download songs, videos or files from suspicious websites. Never share your
personal data with people you don’t know over the internet.
Cyber crime or internet crime
Cybercrime, or computer-oriented
crime, is crime that involves a computer and a network. The computer may have
been used in the commission of a crime, or it may be the target.
Crimes that use computer networks or devices to advance other
ends include: Fraud and identity theft (although this increasingly uses
malware, hacking or phishing, making it an example of both
"computer as target" and "computer as tool” crime) Information
warfare.
