Guest
Article:
A
Basic Guide to the Internet
by Laura Cohen
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,
although estimates are ongoing. It is certain, however, that these
number in the millions and are increasing at a rapid rate.
No one is in
charge of the Internet. There are organizations which develop technical
aspects of this network, 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, 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.
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 World Wide 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 WWW 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 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, led by Web founder Tim Berners-Lee, coordinates
the efforts of standardizing HTML.
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
and Visual Basic are extending the capabilities of the Web. An increasing
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 flux.
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 Express, 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.
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 are library catalogs. 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.
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.
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 Liszt at http://www.liszt.com/ to see an example of a site
that offers a searchable collection 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 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. Newsreader
software gives you access to the newsgroup messages which are stored
on a central computer at the University. For example, the Netscape
Communicator 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.
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 is another commonly-used chat program.
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 http://www.faqs.org/.
Author:
Laura Cohen lcohen@albany.edu.
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