Transcript What is the Internet?

What is the Internet?
The Internet is a whole wide
world of words, pictures, data,
audio and video, which you can
access on your computer.
The Internet is made up of millions of separate web
pages or sites, located on special computers called
"servers" which are connected to each other, to your
computer and to tens of millions of other Internet
users’ computers all around the world
Internet Travels
You can compare using the Internet to
going on a journey, but unlike real travel
you don’t actually have to go anywhere.
Instead the world comes to you! And these
days using the Internet won’t cost you the
earth - there are a wide range of plans
available to suit every budget.
Birth of the Net
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The Internet has had a relatively brief, but explosive
history so far.
It grew out of an experiment begun in the 1960's by the
U.S. Department of Defense.
The DoD wanted to create a computer network that
would continue to function in the event of a disaster,
such as a nuclear war. If part of the network were
damaged or destroyed, the rest of the system still had to
work.
That network was ARPANET, which linked U.S. scientific
and academic researchers. It was the forerunner of
today's Internet.
History Continues
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In 1985, the National Science Foundation (NSF) created
NSFNET, a series of networks for research and
education communication.
Based on ARPANET protocols, the NSFNET created a
national backbone service, provided free to any U.S.
research and educational institution.
At the same time, regional networks were created to link
individual institutions with the national backbone
service.
NSFNET grew rapidly as people discovered its potential,
and as new software applications were created to make
access easier.
And continues….
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Corporations such as Sprint and MCI began to build their
own networks, which they linked to NSFNET. As
commercial firms and other regional network providers
have taken over the operation of the major Internet
arteries, NSF has withdrawn from the backbone
business.
NSF also coordinated a service called InterNIC, which
registered all addresses on the Internet so that data
could be routed to the right system. This service has
now been taken over by Network Solutions, Inc., in
cooperation with NSF.
And still continues
• 1974 TCP published
• 1978 TCP and IP split
• 1984 DNS introduced
• 1989 Number of hosts breaks 100,000
• 1991 World Wide Web launched at CERN
Internet Anatomy
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Even though the Internet is a global network, in many
ways, it resembles a small town, with similar services.
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Let's say you want to send or receive your mail. The Internet has
electronic post offices.
There are online libraries you can use any time of the day or
night, with millions of books and periodicals with unlimited
browsing.
Chat rooms are the Internet equivalent of 24-hour coffee shops,
with people eager to gab anytime you want.
With the explosive growth of the World Wide Web, you can shop,
order a pizza, preview a movie, and listen to radio stations from
around the world. All of these represent different ways of using
the Internet.
World Wide Web
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The World Wide Web, the graphical
portion of the Internet, is the most
popular part of the Internet by far.
The Web physically consists of your
personal computer, web browser
software, a connection to an Internet
service provider, computers called
servers that host digital data and routers
and switches to direct the flow of
information.
WWW
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The Web is known as a client-server
system. Your computer is the client; the
remote computers that store electronic files
are the servers.
Let's say you want to pay a visit to the Louvre
museum website. First you enter the address
or URL of the website in your web browser.
Then your browser requests the web page
from the web server that hosts the Louvre's
site. The Louvre's server sends the data over
the Internet to your computer. Your web
browser interprets the data, displaying it on
your computer screen.
Hypertext
The "glue" that holds the Web
together is called hypertext and
hyperlinks. This feature allow
electronic files on the Web to be
linked so you can easily jump
between them. On the Web, you
navigate through pages of
information based on what interests
you at that particular moment,
commonly known as browsing or
surfing the Net.
Web Pages
A web page is an electronic document written in
a computer language called HTML. Each web
page has a unique address, called a URL, which
identifies its location on the network.
A website has one or more related web pages,
depending on how it's designed. Web pages on
a site are linked together through a system of
hyperlinks, enabling you to jump between them
by clicking on a link. On the Web, you navigate
through pages of information according to your
interests.
E-Mail
To send e-mail, you need a connection to the
Internet and access to a mail server which
can forward your mail. The standard protocol
used for sending Internet e-mail is called
SMTP, for Simple Mail Transfer Protocol. It
works in conjunction with POP servers. POP
stands for Post Office Protocol.
E-mail continues
When you send an e-mail message, your
computer forwards it to an SMTP server.
The server looks at the e-mail address
(like the address on an envelope), then
forwards on it to the recipient's mail
server. When the message is received at
the destination mail server, it is stored
until the addressee retrieves it. account.
Newsgroups
Newsgroups have been around almost
since the dawn of the Internet, enabling
scientists to post questions (and answers) to
other scientists. Today, newsgroups
resemble virtual coffee houses, where
people get together to discuss subjects of
mutual interest. Except with newsgroups, the
communication is written, not verbal.
Newsgroups revolve around specific topics.
You can read what others have written and
then post your own comments.
Newsgroups Continues
First you will need a newsreader program. Both Netscape
Navigator and Internet Explorer have built-in newsreader
programs.
Next, determine which newsgroups interest you and subscribe
to them. Because of the sheer volume of newsgroups available
on the Internet, only subscribe to those that really interest you.
Keep in mind that newsgroups used to be the only way to have
so-called threaded discussions, where related messages are
grouped together. Today, many websites have discussion
groups right on the site. When you are looking for a discussion
to join, don't forget to look at websites as well as newsgroups.
Searching
With hundreds of millions of web pages
online, you could spend a lifetime surfing the
Web, following links from one page to
another. One of the biggest complaints we
hear concerns the difficulty of finding targeted
information. Fortunately, a number of free
online resources can help with the hunt.
You've probably heard of Yahoo!, Excite,
AltaVista and other so-called Internet search
engines. There are literally dozens of these
tools to help you locate what you're looking
for.
Searching some more
Search engines breakdown into two
categories--directories and indexes.
Directories, such as Yahoo!, are good
at identifying general information.
But let's say you want more specific
information, such as biographical
information about Leonardo da Vinci.
Web indexes are the way to go, because they search all the
contents of a website. Indexes use software programs called
spiders or robots that scour the Internet, analyzing millions of
web pages and newsgroup postings, indexing all of the words.
Downloading
With the World Wide Web, downloading files
is as simple as clicking your mouse.
Typically, downloading refers to the method by
which you access digital information from a
remote computer. As it turns out, almost
everything you do on the Web is some form of
downloading. For instance, when you access
a web page, you are actually downloading the
page text and all the associated graphics from
a web server.
Your web browser looks at the file extension (the letters following the
"."). If it recognizes this type of file, it will display it. If it doesn't recognize
it, it will ask you if you want to configure a viewer (tell the browser
which software program to use to view the file). You also have an option
to save the file to your hard drive.
Conferencing
With the Internet, you can see, hear, talk to, and
work with people in different locations around the
world, without the expense of travel. One of the
most compelling features of the Internet may well
be the ability to communicate inexpensively in real
time, via desktop computers.
Conferencing can take many forms, such as
videoconferencing, audio conferencing, multimedia
conferencing, screen-sharing, and, to a lesser
extent, what is referred to in Web parlance as
chat. The cost of implementing these types of
systems can run less than US $100 per computer
and are available for Windows, MacIntosh, Linux
and UNIX operating systems.
Internet Telephony
With the deregulation of the
communications industry, the price of
phone calls has plummeted in recent
years. But even at these reduced rates,
monthly charges can really added up for
chatty folks. A new technology, Internet
telephony, virtually eliminates long
distances charges, allowing you to call
almost anywhere in the world for the
price of a local call. If you have flat-rate
Internet access, you can't beat the price-it's practically free!
Developing a Web Site
Developing an effective website
requires thoughtful planning.
There are six basic stages: planning,
content development, graphic design,
programming, marketing and
promotion, and maintenance.
Depending on your areas of expertise,
you may need assistance on some or
all phases of your project.
Internet Now
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When the World Wide Web began in 1990, few suspected
how successful it would become.
There are now millions of websites with over one billion
web pages.
But as most people are well aware, the Web can be
painfully slow.
Most people connect to the Internet using modems and
telephone lines.
Because the data-carrying capacity of telephone lines,
known as bandwidth, is low, receiving electronic data
can take a long time. New technology promises to
addresses this problem.
And the Future
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Connecting to the Internet using fiber optic lines and via
cable TV will increase bandwidth dramatically, making
the Web more powerful.
Expect to see an explosion of e-commerce, collaborative
projects, videoconferencing and virtual environments.
Many of these applications are already in use in some
form, or are under development.
The incubator for some of the emerging technologies
that will shape the future is known as Internet2. Formed
in 1996 and administered by the University Corporation
for Advanced Internet Development (UCAID), Internet2
is a partnership of universities, corporations and
government agencies.
Internet2
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The project's goals are to create new applications that
can't run over the existing Internet and to develop the
infrastructure that supports those applications.
Internet2 is a not a single network, but a consortium of
hundreds of high-speed networks linked by fiber optic
backbones that span the U.S.
It transmits data at speeds up to 2.4 gigabits per second45,000 times faster than a 56 K modem, allowing
scientists to test their laboratory discoveries in the real
world.
Internet: the next generation
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The next-generation network went online in February,
1999, linking a number of universities around the world.
It should be available for commercial use in a few years.
Then, get ready for 21st century services like interactive
television, virtual 3-D videoconferencing, movies-ondemand, and much more.
High-speed networks will make it possible for
professionals around the world to work in ways never
before possible. For instance, scientists around the
world can share specialized equipment like electron
microscopes.
An example of what is to come
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NASA has developed a Virtual Collaborative Clinic that
connects medical facilities around the U.S., allowing
doctors to manipulate high-resolution, 3-D images of
MRI scans and other medical imaging.
Not only can doctors consult and diagnose, but they can
simulate surgery by using a "CyberScalpel." Virtual
surgery will give surgeons an opportunity to prepare
before ever entering the operating room, reducing the
time required for the actual procedure. Using this kind of
virtual technology, local hospitals will be able to access
resources and skills only available at larger institutions.
NASA plans to use the technology to provide remote
health care to astronauts on extended space journeys.