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