The internet
is a computer network made up of thousands of networks worldwide. No one knows
exactly how many computers are connected to the internet. It is certain,
however, that these number in the millions.
No one is in
charge of the internet. There are organizations which develop the technical aspects
of this network and set standards for creating applications on it, but no
governing body is in control. The internet backbone, through which internet
traffic flows, is owned by private companies.
All
computers on the internet communicate with one another using the Transmission
Control Protocol/ Internet Protocol Suite, abbreviated to TCP/IP. Computers on the internet use a client/server
architecture. This means that the remote server machine provides files and
services to the user’s local client machine. Software can be installed on a
client computer to take advantage of the latest access technology.
An internet
user has access to a wide variety of services: email, file transfer, vast
information resources, interest group membership, interactive collaboration,
multimedia displays, real-time broadcasting, shopping opportunities, breaking
news, and much more.
The internet
consists primarily of a variety of access protocols. Many of these protocols
feature programs that allow users to search for and retrieve material made
available by the protocol.
COMPONENTS OF THE INTERNET: WORLD WIDE
WEB
The world wide web (abbreviated as the web or
www)
Is a system of internet servers that supports
hypertext to
access several internet protocols on a single
interface. Almost
every protocol type available on the internet
is accessible on
the web. This includes e-mail, FTP, Telnet,
and usenet News.
In
addition to these, the world wide web has its own protocol:
Hyper
Text Transfer Protocol or HTTP. These protocols will be
Explained
later in this document.
The
world wide web provides a single interface for accessing
all
these protocols. These creates a convenient and user-
friendly
environment. It’s no longer necessary to be
conversant
in these protocol with separate, command-level
environments.
The web gathers together these protocols into
a
single system. Because of these feature, and because of the
web’s ability to work with multimedia and advanced
Programming
languages, the web is the fastest growing com-
Ponent
of the internet. The operation of the web relies
Primarily
on hypertext as its means of information retrieval.
Hypertext
is a document containing words that connect to
other
documents. The words are called links
and are select-
able
by the user. A single hypertext document can contain
links
to many documents. In the context of the web, words
or
graphic may serve as links to other documents, images,
video
and sound. Links may or may not follow a logical path,
as
each connection is programmed by the creator of the sou-
rce
document. Overall, the web contains a complex virtual
web
of connections among a vast number of documents,
graphics,
video, and sounds.
Producing
hypertext for the web is accomplished by creating
documents
with a language called Hypertext Markup
Language
or HTML. With HTML, tags are placed within the
text
to accomplish document formatting, visual features such
as
font size, italics and bold, and creation of hypertext links.
Graphics
and multimedia may also be incorporated into HTML
document. HTML is an evolving language, with new tag
being
added as each upgrade of the language is developed
and
released. The world wide web consortium (W3C), led by
web
founder Tim Berners- lee, coordinates the efforts of
standardizing
HTML. The w3c now calls the language
XHTML
and
considers it to be an application of the XML language
standard.
The
world wide web consists of files, called pages or home
Pages
containing links to documents and resources through-
out
the internet. The web provides a vast array of experiences
Including
multimedia presentations, real-time collaboration,
Interactive
pages, radio and television broadcasts, and the
automatic
‘’push’’ of information to a client computer.
Programming
language such as java, javascript,visual basic,
cold
fussion and XML are extending capabilities of the web.
A
growing amount of information on the web is served dyna-
mically
from content stored in databases. The web is
therefore
not a fixed entity, but one that is in a constant state
of development and flux. For more complete
information
about
the world wide web, see understanding the world wide
web.
E-MAIL:
Electronic mail or e-mail, allows computer users
locally
and worldwide to exchange messages. Each user
of
e-mail has a mailbox address to which messages are sent.
Messages
sent through e-mail can arrive within a matter of
seconds.
A powerful aspect of e-mail is the option to send
electronic
files to a person’s e-mail address. None ASCII files,
known
as binary files, may be attached to e-mail messages.
These
files are referred to as MIME attachment. MIME stands
for
Multimedia Internet Mail Extension, and was developed to
help
e-mail software handle a variety files types. For example,
a
document created in Microsoft word can be attached to an
e-mail
message and retrieved by the recipient with the
appropriate
e-mail program. Many e-mail program, including
Eudoria,
Netscape messenger, and Microsoft outlook offer the
Ability
to read files written in HTML, which is itself a MIME
type.
TELNET:
Telnet is a program that allows you to log into
computers
on the internet and use online database, library
catalogs,
chat services, and more. There are no graphics in
telnet
sessions, just text. To telnet to a computer, you must
know
its address. This can consists of words (locis, loc, gov) or
numbers
(140. 147. 254. 3). some services require you to
connect
to a specific port on the remote computer. In this
case,
type the port number after the internet address.
Example:
Telnet nri. Reston.va.us 185. Telnet is available on
the world wide web. Probably the most common web-
based
resources available through telnet have been library
catalogs,
though most catalogs have since migrated to the
web.
A link to a telnet resource may look like any other link,
but
it will launch a Telnet session to make the connection.
A
telnet program must be installed on your local computer
and
configured to your web browser in order to work.
With
the increasing popularity of the web, Telnet has become
less frequently
used as a means of access to information on
the
internet.
FTP
: FTP stands for File Transfer
Protocol. This is both a
program
and the method used to transfer files between
computers. Anonymous FTP is an option that allows
users
to transfer files from thousands of host computers
on
the internet to their personal computer account.
FTP
sites contain books, articles, software, games,
images,
sounds, multimedia, course work, data sets,and
more.
If your computer is directly connected to the
internet
via Ethernet cable, you can use one of several
PC software
programs such as WS_FTP for windows, to
conduct
a file transfer. FTP transfers can be performed
on
the world wide web without the need for special
software.
In this case, the web browser will suffice.
Whenever
you download software from a the website
to your local machine, you are using FTP.
E-MAIL
DISCUSSION GROUPS: One of the benefits of the
Internet
is the opportunity it offers to people world
wide
to communicate via e-mail. The is home to a large
community
of individuals who carry out active
discussions
organized around topic-oriented forums
distributed
by email. These are administered by
software programs. Probably the most common
program
is the listserv. A great variety of topics are
covered
by listservs, many of them academic in nature.
When
you subscribe to listser, messages from other
Subscribers
are automatically sent to your electronic
mailbox. You subscribe to listserv by sending an
e-mail
message
to a computer program called a listserver.
Listservers
are located on computer network through
the
world. This program handles subscription
information
and distributes messages to and from
subscribers.
You must have an e-mail account to
participate
in a listserv discussion group. Visit Tile.net at
/http://tile.net/
to see an example an example of a site
that
offers a searchable collection of e-mail discussion
groups.
Majordomo and lisproc are two other programs
that
administers e-mail discussion groups. The
commands
for subscribing to and managing your list
memberships
are similar to those of listserve.
USENET
NEWS: Usenet news is a global electronic
Bulletin
board system in which millions of computer
Users
exchange information on a vast range of topics.
The
major difference between usenet news and e-mail
discussion groups is the fact that usenet messages are
stored
on central computers, and users must connect to
these
computers to read or download the messages
posted
to these groups. This is distinct from e-mail
distribution,
in which messages arrive in the electronic
mailboxes
of each list member. Usenet itself is a set of
machines
that exchanges messages, or articles, from
usenet
discussion forums, called newsgroups. Usenet
administrators
control their own sites, and decide
which
(if any) newsgroups to sponsor and which remote
newsgroups
to allow into the system.
There
are thousands of usenet newsgroups in existence.
While
many are academic in nature, numerous
newsgroup
s are organized around recreational topics.
More
serious computer- related work takes place in
usenet
discussion. A small number of e-mal discussion
groups
also exist as usenet newsgroups.
The
usenet newsfeed can be read by a variety of
Newsreader
software programs. For example, the
Netscape
suite comes with a news reader program
called
messenger. Newsreaders are also available as
Standalone
products.
FAQ:
Faq stands for frequently asked questions. These
are
periodic postings to Usenet newsgroup that contain
a
wealth of information related to the topic of the
newsgroup.
Many FAQs are quite extensive. FAQs are
available
by subscribing to individual usenet
newsgroups.
A web-based collection of FAQ resources
have
been collected by the internet FAQ consortium
and
is available at /http://www.faqs.org/.
CHAT
AND INSTANT MESSENGING: Chat programs allow
User
on the internet to communicate with each other
by
typing in real time. They are sometimes included as a
feature
of a website, where users can log into the ‘’chat
room’’
to exchange comments and information about
the
topics addressed on the site. Chat may
take other,
more wide-ranging forms. For example, America
online
is
well known for sponsoring a number of tropical chat
rooms.
Internet
Relay Chat ( IRC ) is a service through which
Participants
can communicate with each other on
hundreds
of channels. These channels are usually based
on
specific topics. While many topics are frivolous,
substantive
conversations are also taking place.
To
access IRC, you must use an IRC software program.
A
variation of chat is the phenomenon of instant
messenging.
With instant messenging, a user of the web
can
contact another user currently logged in and type a
conversation.
Most famous is American’s online instant
messenger.
ICQ, MSN and Yahoo are other commonly-
used
chat programs.
Other type of real-time communication are
addressed
In
the tutorial ‘’Understanding the world wide web’’
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