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 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: electronic mail, 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.
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COMPONENTS
OF THE INTERNET
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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: HyperText 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.
This creates a convenient and user-friendly environment. It is no longer
necessary to be conversant in these protocols within separate, command-level
environments. The Web gathers together these protocols into a single system.
Because of this feature, and because of the Web's ability to work with
multimedia and advanced programming languages, the Web is the fastest-growing
component 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. These
words are called links and are selectable by the user. A single hypertext
document can contain links to many documents. In the context of the Web, words
or graphics 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 source document. Overall, the Web contains a complex virtual
web of connections among a vast number of documents, graphics, videos, 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 the creation of hypertext links. Graphics and multimedia
may also be incorporated into an HTML document. HTML is an evolving language,
with new tags 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 throughout 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 languages such as Java, JavaScript, Visual Basic, Cold Fusion and
XML are extending the capabilities of the Web. A growing amount of information
on the Web is served dynamically 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. Non-ASCII files, known as binary files, may be attached to
e-mail messages. These files are referred to as MIME attachments.MIME stands
for Multimedia Internet Mail Extension, and was developed to help e-mail
software handle a variety of file 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 programs, including
Eudora, 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 databases, 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 consist 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 an 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 Web site to your local machine, you are using FTP. You can also
retrieve FTP files via search engines such as FtpFind, located at
/http://www.ftpfind.com/. This option is easiest because you do not need to
know FTP program commands.
E-MAIL
DISCUSSION GROUPS
One of
the benefits of the Internet is the opportunity it offers to people worldwide
to communicate via e-mail. The Internet is home to a large community of
individuals who carry out active discussions organized around topic-oriented
forums distributed by e-mail. 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 a listserv, messages from other subscribers are
automatically sent to your electronic mailbox. You subscribe to a listserv by
sending an e-mail message to a computer program called a listserver.
Listservers are located on computer networks throughout the world. This program
handles subscription information and distributes messages to and from
subscribers. You must have a e-mail account to participate in a listserv
discussion group. Visit Tile.net at /http://tile.net/ to see an example of a
site that offers a searchablecollection of e-mail discussion groups.
Majordomo
and Listproc are two other programs that administer e-mail discussion groups.
The commands for subscribing to and managing your list memberships are similar
to those of listserv.
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 newsgroups are organized around recreational topics. Much
serious computer-related work takes place in Usenet discussions. A small number
of e-mail 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 newsreader program called Messenger.
Newsreaders are also available as standalone products.
FAQ,
RFC, FYI
FAQ
stands for Frequently Asked Questions. These are periodic postings to Usenet
newsgroups 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 has been
collected by The Internet FAQ Consortium and is available at
/http://www.faqs.org/.
RFC
stands for Request for Comments. These are documents created by and distributed
to the Internet community to help define the nuts and bolts of the Internet.
They contain both technical specifications and general information.
FYI
stands for For Your Information. These notes are a subset of RFCs and contain
information of interest to new Internet users.
Links to
indexes of all three of these information resources are available on the
University Libraries Web site at
/http://library.albany.edu/reference/faqs.html.
CHAT
& INSTANT MESSENGING
Chat
programs allow users on the Internet to communicate with each other by typing
in real time. They are sometimes included as a feature of a Web site, 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 topical chat rooms.
Internet
Relay Chat (IRC) is a service through which participants can communicate to
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 on the Web can contact another user currently logged in and
type a conversation. Most famous is America Online's Instant Messenger. ICQ,
MSN and Yahoo are other commonly-used chat programs.
Other
types of real-time communication are addressed in the tutorial Understanding the
World Wide Web.
MUD/MUSH/MOO/MUCK/DUM/MUSE
MUD
stands for Multi User Dimension. MUDs, and their variations listed above, are
multi-user virtual reality games based on simulated worlds. Traditionally text
based, graphical MUDs now exist. There are MUDs of all kinds on the Internet,
and many can be joined free of charge.
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