DEFINITION OF INTERNET
Internet is a global interconnected network of thousands of
networks linking academic, government, and commercial institutions, and other
organizations and individuals.
OR
It is a global network that connects more than tens of
thousands of networks, millions of large multi-user computers and tens of
millions of users in more than 100 countries.
OR
It is a
public communication world wide network.
OR
The internet, sometimes called simply “the Net”, is a loosely
organized global collection of thousands of networks.
WAYS TO CONNECT YOUR PC TO THE
INTERNET
i.
Via An Information Service Gateway:-
You can connect your PC to the internet via commercial
information service, such as America
ii.
Via An Internet Service Provide (ISP):-
An Internet Service Provides is any company that offers for a
fee, a server computer and the software needed to access the internet. You can
connect your PC easily via ISP.
iii.
Via Network Connection:-
At this level you PC is wired directly into the Internal,
usually via a Local Area Network (LAN). A LAN will normally have a high speed
digital link to the internet, which is shared by the users on the LAN. Direct
connection via a LAN is almost immediate, and is available 24 hours a day.
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| Network Connection |
DEVICES USED IN INTERNET TECHNOLOGY
Devices
that handle the movement of data in computer network are following:
1) Modem
2) The Front
End Processor
3) The
Multiplexor
4) Router
1) MODEM
A modem is
a device that converts digital signals into analog signals and vice versa. The
modem that converts digital signals into analog signals is called modulator. A modem that converts analog
signals to digital signals is called demodulator.
A modem is always required for two computers to communicate over a
telephone line.
Modem data speed:
Modems
differ in their transmission speeds, measured in bits per second. (bps). Most
people today measure modem speeds, use the term band rate. Band rate is the
number of times that the signal being used to transmit data changes. Modems, today
commonly transmit data at 14,400 bps to 56,000 bps over standard phone line.
Types of modem:
There are
two main types of modems in the way they connect to the telephone line.
i.
Acoustic
coupler modem:-
It includes
a cradle to hold the telephone handset.
ii.
A direct
connect modem:-
It is
directly connected to the telephone line by means of a telephone jack. There
are two types of direct connect modem.
a. External
Modem
An
external modem is separate from the computer. An external modem sits in a box
linked to the serial port of the motherboard. It uses phone cable to connect to
the telephone network through standard modular phone jacks. Its main advantage
is that it can be used with a variety of computers.
b. Internal
Modem
An
internal modem is installed on a circuit board inside the computer’s chassis.
Most computers today come with an internal modem as standard equipment. Most
modems today also have fax capability. Modems used in the notebook and laptop
computer are in the form of P.C cards.
2) FRONT END
PROCESSOR
The
Front End Processor is a processor that is used to offload certain data
communication tasks from the host processor. Data may travel to a large
computer through front end processor, which is actually a computer in itself.
Its purpose is to relieve the central computer of some communication task. In
addition, a front end processor usually performs error detection and recovery
function.
3) THE
MULTIPLEXOR
The
multiplexor is an extension of the front end processor. The multiplexor
collects data from several low speed devices, such as terminals and printers.
It then concentrates the data and sends them over a single communication
channels to the front end processor. The multiplexor also receives and
distributes host output to the appropriate remote terminals.
4) ROUTER
Router is a
special computer that directs communication traffic when several networks are
connected together. If traffic is clogged on one path, the router can determine
an alternate path. Routers help to bridge to gap between incompatible networks
by performing the necessary protocol conversion to route messages to their
proper destination. Routers are being replaced with 1P switches, which are less
expensive.
USES OF INTERNET
The
Internet provides scientists, engineers, researchers, educators, students,
business people, consumers, and other with a variety of services.
1) ELECTRONIC MAIL (E-MAIL)
Internet
users can send mail messages data files, and software programs to other internet
users and to users of commercial network. Actually E-Mail, is the process of
sending messages directly from one computer to another: E-Mail works, of
course, only if the intended receiver has a computer to receive the message.
2) VOICE MAIL
Voice Mail
is a system in which a spoken message is digitized and stored in the
recipient’s voice mail box. Later the recipient can dial the mail box. And the
system delivers the message in audio form.
3) THE INTERNET TELEPHONE
The
Internet phone capability lets you call people at other computers on the
Internet. To make a phone call we simple pick up a telephone, which is linked
to a world wide communications network and speak into his microphone and listen
through its speaker. Millions of users with multimedia PCs have these same
capabilities: access to Internet, a mike, speaker and Internet telephone
software.
4) CYBER TALK/INTERNET RELAY CHAT/ CHIT
CHAT
The Internet
Relay Chat (IRC) protocol allows users to join and participate in group chat
session. A chat session is when two or more Internet users carry on a typed,
real time, online conversation. Chatting is a favourite pastime of millions of
cyber nauts.
5) REMOTE LOGIN (TELNET)
To find and
retrieve information located on remote Internet sites, Remote login allows
users to connect to hosts all overt the world from just about any where. The
protocol that makes remote login possible is called Telnet.
6) DOWNLOADING FILES (FTP)
The File Transfer Protocol allows you to
download and upload files on the Internet. Thousands of FTP sites offer
millions of useful files-most are free for the asking. You can download
exciting games, colourful art, music, statistics, maps, photos, utility and
applications programs, basically any thing that can be stored digitally.
7) NEWSGROUP (USE NET)
Usenet is
an informal network of computers that allows the posting and reading of
messages in newsgroup on specific topics. The internet is the home of thousands
of Usenet newsgroups and discussion groups on about every imaginable topic from
molecular biology to educational psychology, folk music to international
politics, any thing related to computers. Millions of readers check into one or
more newsgroups regularly.
8) WORLD WIDE WEB
In 1990 Dr. Tim Berners Lee, a physicist saw the
set of links from computer to computer to computer as a spider’s web; hence the
name web was given. The hottest “place” on the Internet is the World Wide Web,
a collection of multimedia documents created by organizations and users all
over the world. These documents are link in a hypertext web that allows users
to explore far and wide with simple mouse clicks.
9) HOME PAGE
Information
on the web is viewed in pages. A web page can contain text plus any or all of
these multimedia elements. When you navigate to a particular web site, the
first page you will normally view is the site’s homepage. The homepage is starting point for accessing information
at a site or in a particular area. Web pages are often written directly in a
language called Hyper Text Markup Language (HTML). If you want to have your own
home page you must have a service provider that will store it for you and let it
be accessible to other people.
10) BROWSING THE WEB
In 1993, Marc Andreessen invented the browser.
It is software used to explore the Internet. Two well designed browsers are
Netscape Navigator an Microsoft Internet Explorer. The browsers allow you to
explore the web by clicking on hot links, words or pictures that act as
buttons, allowing you to explore with mouse clicks. Hot text is typically, but
not always, underlined and displayed in a different colours.
11) HOT SEARCH ENGINES
Search
engine is an Internet resource discovery tool that lets people find the
information by keyword(s) searches. Search engines vary in size, content, and
search methodology. Some useful hot search engines are Alta Vista, Yahoo,
Infoseek, Exite, Lycos, Web crawler, Hot Bot and Open Text Index. A search
engine like Alta vista or Web Crawler offers a much more complete database. A
search engine uses software to explore the Web, retrieve information, and add
it to the database.
12) VIDEO CONFERENCING
Video
conferencing is the teleconferencing whose components usually include a large
screen, video cameras and an online computer system to record communication
among participants. While they are talking they can continue to brows the web,
exchange electronic photos, or even play games.
13) INSTANT BANKING
People can
pay for goods and services by electronic funds transfer from various accounts
using computer technology. Bank and other financial institutions transfer funds
among themselves electronically on both the national and international level.
14) ONLINE SERVICES
Some
companies offer a wide range of services. Users can connect their personal
computers to commercial, consumer-oriented communication systems via telephone
lines, such as America Online (AOL) or the Microsoft Network, that offers a
variety of services, usually including access to the Internet. Online service
is also called an information utility.
15) MAILING LIST
The Internet mailing list is a
cross between a newsgroup and E-Mail. Mailing lists are like newsgroup in that
they allow people to discuss issues of common interest.
ABUSES OF INTERNET
1. HACKING
a. Disturbance
The
Internet is a digital wild west without law and order. The Internet is a public
land; therefore accessibility is one of the problems on the Internet. With
unlimited accessibility, mischievous hackers disrupt the flow of information on
the Internet. These electronic assaults are on the routers and other
communications devices that route data from node to node on the Net.
b. Stealing
Hackers
steal valuable softwares, traded secrets, distributed copyrighted photos and
songs, and run online securities scams (trick, fraud).
2. VIRUS
Virus
is a set of illicit instructions, passes itself on to other programs or
documents with which it comes in contact. Hackers also plant computer viruses
on the Internet, disguised as enticing downloadable files. Once downloaded
virus infects the PC and creates havoc, often destroying files and sometimes even
entire hard disks. Virus is a contagious.
3. WORM
A worm is a program that transfers itself from
computer to computer over a network and plants itself as a separate file on the
target computer’s disks. The worm may be injected into the network and
multiplied uncontrollably, clogging the memories of infected computers until
they could no longer function
4.
UNSUITABLE SITES
Parental, unfriendly sites are frequently available,
which are socially unwanted for people of all ages as they are capable of
shakenning of good built character.
5.
UNETHICAL RELATIONSHIP
Frequent sitting on Internet without specific
purpose rather, just for developing mutual relationship by chatting may result
in unethical relationship especially between immature youngsters and youths.
6. WASTAGE OF TIME
Now a days
youngsters waste their valuable time by chatting which must be spent on their
studies.
7. SPAMMING (JUNK E-MAIL)
Unrequested
message (junk mail) are distribute across the Internet which is called
spamming. Spam messages are mostly advertising for commercial products or
services. Privacy invasion in the form of junk e-mail had become.
Unfortunately, a common event. Furious spam recipients sometimes respond to the
perpetrator by flaming, sending
insulting messages in return.
8. MISINFORMATIVE
There are
no guarantees. The Internet is full of misinformation. Just because something
is on the Internet does not mean it is true. If you are doing serious research
on the Internet, be sure to back it up with other sources especially non
Internet sources.
9. THREATING
People on
Internet are sometimes threatened. They receive threating e-mails. People
sometimes use Internet as a source of hounding, either by chatting or e-mails.
10. PRIVACY PROBLEMS
You are
being watched, when you visit a web site, it can easily collect the city you
are calling from, the site from which you just came and of course, everything
you do while you are at the site. Software can also discover and record the
hardware and software you use. Software can ever monitor user’s click stream
(series of mouse clicks) that link from site to site. Thus, a history of what a
user chooses to view on the web can be recorded and used for a variety of
purposes by managers and marketers.
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| The Internet |
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