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 an
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. For more information, read one of the FAQs
devoted to MUDs available at the FAQ site at
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