Internet Introduction


 Internet Introduction





Introduction
What is the internet?
History & development of the internet.
Who pays for the internet?
What makes the internet work?
The client/server Model
The use of local client
Electronic mail on the internet.
How does E-mail work?
Reading an internet address
Types of discussion lists
Introduction to network news
How does network news work
Newsgroup: what’s in a name?
Remote Login and File Transfer
Introduction to FTP, File Transfer Protocol
Resources available to you via FTP
Introduction to Gopher
Introduction to the world wide web
Uniform resource locators, or URLs
WWW clients, or “Browsers”
Chatting
A look at search engines.

 

1-Introduction:

By
the turn of the century, information, including access to the Internet,
will be the basis for personal, economic, and political advancement.
The popular name for the Internet is the information superhighway. Whether
you want to find the latest financial news, browse through library catalogs,
exchange information with colleagues, or join in a lively political
debate, the Internet is the tool that will take you beyond telephones,
faxes, and isolated computers to a burgeoning networked information
frontier. 

The Internet supplements the traditional tools you use to gather information,
Data Graphics, News and correspond with other people. Used skillfully,
the Internet shrinks the world and brings information, expertise, and
knowledge on nearly every subject imaginable straight to your computer. 

What
is the Internet? 

The
Internet links are computer networks all over the world so that users
can share resources and communicate with each other. Some computers,
have direct access to all the facilities on the Internet such as the
universities. And other computers, eg privately-owned ones, have indirect
links through a commercial service provider, who offers some or all
of the Internet facilities. In order to be connected to Internet, you
must go through service suppliers. Many options are offered with monthly
rates. Depending on the option chosen, access time may vary. 

The Internet is what we call a metanetwork, that is, a network of networks
that spans the globe. It’s impossible to give an exact count of the
number of networks or users that comprise the Internet, but it is easily
in the thousands and millions respectively. The Internet employs a set
of standardized protocols which allow for the sharing of resources among
different kinds of computers that communicate with each other on the
network. These standards, sometimes referred to as the Internet Protocol
Suite, are the rules that developers adhere to when creating new functions
for the Internet. 

The Internet is also what we call a distributed system; there is no
central archives. Technically, no one runs the Internet. Rather, the
Internet is made up of thousands of smaller networks. The Internet thrives
and develops as its many users find new ways to create, display and
retrieve the information that constitutes the Internet. 

History
& Development of the Internet:

In
its infancy, the Internet was originally conceived by the Department
of Defense as a way to protect government communications systems in
the event of a military strike. The original network, dubbed ARPANet
(for the Advanced Research Projects Agency that developed it) evolved
into a communications channel among contractors, military personnel,
and university researchers who were contributing to ARPA projects. 

The network employed a set of standard protocols to create an effective
way for these people to communicate and share data with each other. 

ARPAnet’s popularity continued to spread among researchers, and in the
1980’s the National Science Foundation, whose NSFNet, linked several
high speed computers, took charge of the what had come to be known as
the Internet. 

By the late 1980’s, thousands of cooperating networks were participating
in the Internet. 

In 1991, the U.S. High Performance Computing Act established the NREN
(National Research & Education Network). NREN’s goal was to develop
and maintain high-speed networks for research and education, and to
investigate commercial uses for the Internet. 

The rest, as they say, is history in the making. The Internet has been
improved through the developments of such services as Gopher and the
World Wide Web. 

Even though the Internet is predominantly thought of as a research oriented
network, it continues to grow as an informational, creative, and commercial
resource every day and all over the world. 

Who
Pays for the Internet?

There
is no clear answer to this question because the Internet is not one
“thing”, it’s many things. No one central agency exists that
charges individual Internet users. Rather, individuals and institutions
who use the Internet pay a local or regional Internet service provider
for their share of services. And in turn, those smaller Internet service
providers might purchase services from an even larger network. So basically,
everyone who uses the Internet in some way pays for part of it. 

2-what
makes the internet work? 

The
unique thing about the Internet is that it allows many different computers
to connect and talk to each other. This is possible because of a set
of standards, known as protocols, that govern the transmission of data
over the network: TCP/IP (Transmission Control Protocol/Internet Protocol).
Most people who use the Internet aren’t so interested in details related
to these protocols. They do, however, want to know what they can do
on the Internet and how to do it effectively.
 

The
Client/Server Model:

The
most popular Internet tools operate as client/server systems. You’re
running a program called a Web client. This piece of software displays
documents for you and carries out your requests. If it becomes necessary
to connect to another type of service–say, to set up a Telnet session,
or to download a file–your Web client will take care of this, too.
Your Web client connects (or “talks”) to a Web server to ask
for information on your behalf.

The
Web server is a computer running another type of Web software which
provides data, or “serves up” an information resource to your
Web client. 

All
of the basic Internet tools–including Telnet, FTP, Gopher, and the
World Wide Web–are based upon the cooperation of a client and one or
more servers. In each case, you interact with the client program and
it manages the details of how data is presented to you or the way in
which you can look for resources. In turn, the client interacts with
one or more servers where the information resides. The server receives
a request, processes it, and sends a result, without having to know
the details of your computer system, because the client software on
your computer system is handling those details. 

The advantage of the client/server model lies in distributing the work
so that each tool can focus or specialize on particular tasks: the server
serves information to many users while the client software for each
user handles the individual user’s interface and other details of the
requests and results. 

The
Use of Local Clients:

Every
computer should be equipped with basic client software packages that
allow you to perform functions such as electronic mail, Telnet, Gopher,
and FTP. 

Electronic
mail on the internet:

Electronic
mail, or e-mail, is probably the most popular and widely used Internet
function. E-mail, email, or just mail, is a fast and efficient way to
communicate with friends or colleagues. You can communicate with one
person at a time or thousands; you can receive and send files and other
information. You can even subscribe to electronic journals and newsletters.
You can send an e-mail message to a person in the same building or on
the other side of the world.

How
does E-mail Work?

E-mail
is an asynchronous form of communication, meaning that the person whom
you want to read your message doesn’t have to be available at the precise
moment you send your message. This is a great convenience for both you
and the recipient.

On
the other hand, the telephone, which is a synchronous communication
medium, requires that both you and your listener be on the line at the
same time in order for you to communicate (unless you leave a voice
message). It will be impossible to discuss all the details of the many
e-mail packages available to Internet users. 

Fortunately, however, most of these programs share basic functionality
which allow you to: 

     *send and receive mail messages 

     *save your messages in a file 

     *print mail messages 

     *reply to mail messages 

     *attach a file to a mail message 

Reading
an Internet Address:

To use Internet
e-mail successfully, you must understand how the names and addresses
for computers and people on the Internet are formatted. Mastering this
technique is just as important as knowing how to use telephone numbers
or postal addresses correctly. 

Fortunately, after you get the hang of them, Internet addresses are
usually no more complex than phone numbers and postal addresses. 

And, like those methods of identifying a person, an organization, or
a geographic location–usually by a telephone number or a street address–Internet
addresses have rules and conventions for use. 

Sample Internet Address: custcare@aucegypt.edu

     The Internet address has three parts: 

  1.a user name [custcare in the example above] 

  2.an “at” sign (@) 

  3.the address of the user’s mail server [aucegypt.edu in
the example above] Sometimes it’s useful to read an Internet address
(like custcare@aucegypt.edu) or a domain name from right to left because
it helps you determine information about the source of the address. 

An address like 201B6DQF@asu.edu doesn’t tell me much about the person
who’s sending me a message, but I can deduce that the sender is affiliated
with an educational institution because of the suffix edu. 

The right-most segment of domain names usually adhere to the naming
conventions listed below: 

 

EDU  
Educational sites in the United States 

COM  Commercial sites in the United States 

GOV  Government sites in the United States 

NET   Network administrative organizations 

MIL    Military sites in the United States 

ORG  Organizations in the U.S. not covered by the categories above
(e.g., non-profit orginaizations).

.xx     
where xx is the country code (e.g., .eg for Egypt).

Introduction:

Once
you’ve become adept at using e-mail, you may want to communicate with
others on the Internet who share your interests. Newsgroups are one
way to do this; the other is through an electronic discussion group.
An electronic discussion is a group of persons who have come together
to discuss a particular topic via e-mail. There are several methods
that network users can use to participate in electronic discussions;
however, the basic purpose is to bring together persons with similar
interests to share information, ideas, problems, solutions, and opinions.
Since an electronic discussion is conducted by e-mail, it’s commonly
called a mailing list. 

If you find yourself interested in a topic, you can subscribe to a suitable
mailing list. From then on, any message sent to the mailing list is
automatically distributed as electronic mail to you–as well as to all
previously subscribed members of that particular discussion. The beauty
of a mailing list is that traffic (the mail generated by that list)
covers a specific topic and the 

mail it generates comes straight to your electronic mailbox, without
any extra work on your part.  There are thousands of mailing lists
operating on the Internet, dedicated to myriad topics. Some are created
to serve local needs only (i.e., a list for the members of a regional
computer user group), while many are open to anyone on the network.
There are discussions on professional topics, vocational subjects, and
topics of personal interest. You can roughly separate the thousands
of mailing lists available on the Internet into the following groups: 

Types
of discussion lists:

Moderated vs. Unmoderated
Lists 

Mailing lists
can be moderated or unmoderated. The distinction is whether messages
are automatically forwarded to all subscribers (unmoderated) or whether
a moderator (a human being) first screens and perhaps combines similar
messages before sending them to subscribers (moderated). 

Open vs. Closed Lists
Electronic discussions
can also be “open” or “closed.” Anyone can subscribe to
an open discussion, but a closed discussion is limited to a particular
group of persons, for example, those in a particular professional
field. 

Introduction
to network news:

Network
News (sometimes referred to as Usenet News) is a service comprised of
several thousand electronic discussions providing users an effective
way to share information with others on just about any topic.

If
you’re unclear about the concept of Network News, it’s helpful to think
about a bulletin 

board that you might see on campus. 

Here, one might find posted messages advertising a futon for sale, asking
for students to join a math study group.  In the newsgroup environment,
the same kind of process take place: 

User X may access a newsgroup on a particular topic and post a message,
question, or respond to a previously posted message, and anyone accessing
that newsgroup would then be able to see User X’s message. 

Network News newsgroups provide this same kind of forum online, where
users have access to the messages posted by all other users of that
newsgroup. 

Network News has been described as an “international meeting

place”
where you’re likely to find a discussion going on just about anything.
 

How
Does Network News work?

Messages
posted on Network News newsgroups are sent from host computer to host
computer all over the world, using the network news transfer protocol. 

Because Network News newsgroups are located on one server, Network News
is a very efficient way to share information that might otherwise be
disseminated to several individual users. 

This way, several people can read a given newsgroup message, but the
host system stores only one copy of it. 

Newsgroups:
What’s in a Name?

As
mentioned before, Network News is essentially made up of newsgroups,
each newsgroup a collection of messages focusing on a related theme. 

You can probably find a newsgroup on any topic, no matter how arcane
or bizarre. 

A newsgroup’s name gives you a good idea of that group’s focus, and
also illustrates the hierarchical naming scheme given to newsgroups. 

Newsgroups with the prefix comp, for example, are for computer-related
topics. 

After the initial prefix, you’ll see an additional series of names assigned
to the newsgroup that tell its specific concern: Note the following
examples: 

 comp.mac.performa
for “computers–macintosh–performas” 

  rec.auto.antique for “recreation–autos–antiques” 

  alt.backrubs for “alternative–backrubs” 

  soc.culture.japan for “social–culture–japan”

Remote
Login & File Transfer:
Introduction to telnet:

Telnet is the
protocol used to establish a login session on a remote computer on the
network. While many computers on the Internet require users to have
authorization, others are open to the public and can be logged onto
with telnet. Telnet is not a method to transfer files from one machine
to another, but rather is a way to remotely connect to another system
with priveleges to run specific programs on that system. Some uses of
the Telnet protocol include: 

connecting to a library catalog to search that library’s collection
connecting to a location that allows public priveleges to search its
campus information system connecting to a location that gives
you an up-to-the minute weather report 

Basic
Telnet Commands

open
– establishes a connection to the specified host.close – closes an open
connection and leaves you in the telnet software quit – closes any open
telnet sessions and exits the telnet software. When using a telnet
program like NCSA Telnet, you invoke these commands by way of pull-down
menus or command keys. 

Introduction
to FTP, File Transfer Protocol:

Basic commands in FTP:

To do FTP, a
user invokes one of two commands: 

get the command for transferring a file from another server to your
own computer. 

put the command for moving a file from your computer to another one. 

Who can do FTP? Anonymous vs. authorized priveleges

On many servers, called anonymous FTP servers, anyone can do FTP. All
that is required to login is a username (anonymous) and a password (your
e-mail address). To get an idea of the many resources available via
FTP, you can look at this selected list of FTP servers. 

Other servers require you to be a registered “authorized”
user before you’re permitted to do FTP. In such a case, you would need
to contact the system operator for the server you wish to access, and
request an authorization and a password. Getting an authorization and
password might mean that you can get and put only to specific subdirectories
on that server.

Resources
available to you via FTP

Freeware

    
When
you download freeware, the author continues to carry the copyright to
the software, but permits you to use the program for free. You can share
freeware with others, as long as you don’t sell it. 

Public Domain
When
you download public domain software, you can use it freely. The creator
carries no copyright, and has released it for anyone to use. There are
no limits on distribution or sale–and anyone can modify the program. 

Shareware 

    
When you download shareware, the author continues to carry the copyright
to the software, but you’re permitted short-term use of the program
for evaluation purposes. 

     At the end of evaluation period, you must either
pay the copyright holder for the program or destroy all copies you’ve
made of it. 

Introduction
to Gopher:

Gopher
is a client/server system that allows you to access many Internet resources
simply by making selections from a sequence of menus. Each time you
make a selection, Gopher carries out your request to the computer that
contains the information and “serves” it up. For example,
if you select a menu item that represents a text file, Gopher will get
that file–wherever it happens to be–and display it for you. As you
use Gopher, some menu items lead to other menus. If you choose one of
these, Gopher will retrieve the new menu and display it for you. Thus
you can move from menu to menu, using only a few key strokes or a mouse
to navigate. The power of Gopher is that the resources listed in a menu
may be anywhere on the Internet. As Gopher connects to computers to
comply with your menu selection, you don’t need to be preoccupied with
the behind-the-scenes work of connecting to and disconnecting from these
various computers. Gopher does this for you without your even needing
to be aware of it. This automatic connecting makes Gopher popular and
useful. 

Where
did Gopher come from?

“Born”
in April 1991, gopher began as a project at the Microcomputer, Workstation,
and Networks Center at the University of Minnesota to help people on
campus get answers to computer-related questions. At the time, the computer
center staff had accumulated answers to thousands of questions regarding
computers and software.

What was needed was an easy and efficient way to deliver this information
to students, faculty and staff. Thus, the creation of Gopher reaffirms
the adage that necessity is the mother of invention. 

Why
is it called Gopher?

The
name “Gopher” is appropriate for three reasons: 

   1.Just as a real gopher successfully navigates beneath
the prairie, the Internet Gopher tunnels through the invisible paths
of the Internet to help you find the information you want. 

   2.The name refers to someone who fetches things or provides
service for other people. 

   3.The Golden Gopher is the mascot of the University of
Minnesota. 

Introduction
to the World Wide Web 

The
World Wide Web (also referred to as WWW or W3) is the fastest growing
area of the Internet. While gopher was an important step in allowing
users to “browse” through the Internet’s vast resources, the
World Wide Web has raised excitement about the Internet to new heights. 

What makes the World Wide Web appealing and innovative is its use of
hypertext as a way of linking documents to each other. A highlighted
word or phrase in one document acts as a pointer to another document
that amplifies or relates to the first document. When looking at a WWW
document, the reader doesn’t have to follow every pointer, or link (also
called a hypertext link), only those that look interesting or useful.
In this way, the user tailors the experience to suit his or her needs
or interests. The other very appealing aspect of the World Wide Web
is the use of graphics and sound capabilities. Documents on the WWW
include text, but they may also include still images, video, and audio
for a very exciting presentation. People who create WWW documents often
include a photograph of themselves along with detailed professional
information and personal interests. (This is often called a person’s
home page.) 

What
makes the WWW work? 

WWW
is another example of client/server computing. Each time a link is followed,
the client is requesting a document (or graphic or sound file) from
a server (also called a Web server) that’s part of the World Wide Web
that “serves” up the document. The server uses a protocol
called HTTP or HyperText Transport Protocol. The standard for creating
hypertext documents for the WWW is HyperText Markup Language or HTML.
HTML essentially codes plain text documents so they can be viewed on
the Web.

Uniform
Resource Locators, or URLs:

A
Uniform Resource Locator, or URL is the address of a document you’ll
find on the WWW. Your WWW browser interprets the information in the
URL in order to connect to the proper Internet server and to retrieve
your desired document. Each time you click on a hyperlink in a WWW document,
you’re actually instructing your browser to find the URL that’s embedded
within the hyperlink. 

The elements in a URL:Protocol://server’s address/filename

 Hypertext protocol: http://www.aucegypt.edu

Gopher protocol: gopher://gopher.umm.tc.edu

File Transfer Protocol: ftp://ftp.dartmouth.edu

Telnet Protocol: telnet://pac.carl.org

News Protocol: news:alt.rock-n-roll.stones

WWW
Clients, or “Broswers”:

The program
you use to access the WWW is known as a browser because it “browses”
the WWW and requests these hypertext documents. Browsers can be graphical,
like Netscape and Mosaic, allowing you to see and hear the graphics
and audio; text-only browsers (i.e., those with no sound or graphics
capability) are also available. All of these programs understand 

http and other Internet protocols such as FTP, gopher, mail, and news,
making the WWW a kind of “one stop shopping” for Internet
users.

Chatting: 

Internet
Relay Chat (IRC), the other method for Internet conversation, is less
common than talk because someone must set up the Chat before others
can join in. Chat sessions allow many users to join in the same free-form
conversation, usually centered around a discussion topic. When users
see a topic that interests them, they type a command to join and
then type another command to choose a nickname. Nicknames allow people
in the session to find you on IRC Networks or Channels. 

A
look at search engines:

The World Wide
Web is “indexed” through the use of search engines, which
are also referred to as “spiders,” “robots,” “crawlers,”
or “worms”. These search engines comb through the Web documents,
identifying text that is the basis for keyword searching. Each search
engine works in a different way. Some engines scan for information in
the title or header of the document; others look at the bold “headings”
on the page for their information. The fact that search engines gather
information differently means that each will probably yield different
results. Therefore, it’s wise to try more than one search engine when
doing Web searching.

The
list below lists several search engines and how each one gathers information,
plus resources that evaluate the search engines. 

Selected Search Engines
(listed alphabetically)

Alta Vista 
Alta Vista,
maintained by The Digital Equipment Corp., indexes the full text of
over 16 million pages including newsgroups. Check out the Alta Vista
Tips page. 

Excite Netsearch
Excite includes
approximately 1.5 million indexed pages, including newsgroups. Check
out the Excite NetSearch handbook. 

InfoSeek Net
Search 

Indexes full
text of web pages, including selected newsgroups and electronic journals. 

Just under one-half million pages indexed. Check out the InfoSeek Search
Tips. 

Inktomi
As of December
1995, the Inktomi search engine offers a database of approximately 2.8
million indexed Web documents and promises very fast search retrievals.
Results are ranked in order of how many of your searched terms are used
on the retrieved pages. 

Lycos
Lycos indexes
web pages (1.5 million +), web page titles, headings, subheadings, URLs,
and significant text. 

Search results are returned in a ranked order. 

Magellan 
Magellan indexes
over 80,000 web sites. Search results are ranked and annotated. 

Open Text
Index 

Indexes full
text of approximately 1.3 million pages. Check out the Open Text Help
pages for tips on using this search engine. 

WebCrawler
Maintained by
America Online, WebCrawler indexes over 200,000 pages on approximately
75,000 web servers. URLs, titles, and document content are indexed. 

WWWW — World
Wide Web Worm 

Approximately
250,000 indexed pages; indexed content includes hypertext, URLs, and
document titles.

Yahoo 
A favorite directory
and search engine, Yahoo has organized over 80,000 Web sites (including
newsgroups) into 14 broad categories. Yahoo also maintains a comprehensive
list of links to Yahoo – Computers and Internet:Internet:World Wide
Web: Searching the Web other web search engines, indexes, and guides. 

Finally
the internet is a huge source of information in all fields of knowledge. 

Datum will take your hand through this incredible world of 

information to get what you need in a fast, reliable 

and professional way. 

Source
: DATUM Company and Internet Access
Magazine .

Source Article