Transcript Lesson 2

Unit 1 — Computer Basics
Lesson 2 — The
Internet and the World
Wide Web
Objectives
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Describe the origin of the Internet.
Describe how the Internet works.
Describe the major features of the Internet.
Explain the difference between the World
Wide Web and the Internet.
Lesson 2 — The Internet and the World Wide Web
Objectives (continued)
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Explain how to connect to the Internet.
Describe a browser.
Understand browser terminology.
Understand and use browser features.
Lesson 2 — The Internet and the World Wide Web
Evolution of the Internet
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The Internet is a worldwide network of smaller networks.
The Internet evolved from the ARPANET.
The ARPANET was the first large-scale network, created
around 1969.
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The World Wide Web (WWW) was born in 1992.
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This spurred more growth of the Internet.
The first Web browser, Mosaic, was released in 1993.
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It was developed as a government research project.
This triggered an explosion in Internet use and growth.
Lesson 2 — The Internet and the World Wide Web
How Does the Internet Work?
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Internet computers talk with each other in a manner
similar to mailing a letter to some one: by sending it to an
address.
Internet computers all have a unique address.
Computers communicate using TCP/IP protocol.
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This is the international standard for exchanging data.
TCP establishes a connection between two host computers.
The IP protocol allows you to enter an address of a computer
and send something to that address.
You can enter an address as a domain name.
Lesson 2 — The Internet and the World Wide Web
Example of Internet Communication
This figure shows a very
simplified version of how
the Internet works. One
computer mails a letter to
another computer, and
the TCP/IP protocol
handles the addressing
between the two
machines.
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Lesson 2 — The Internet and the World Wide Web
Major Features of the Internet
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The Internet is made up of many services,
including
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The World Wide Web (WWW)
E-mail
Chat rooms
Mailing lists
FTP sites
Newsgroups
Lesson 2 — The Internet and the World Wide Web
The World Wide Web
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The WWW is NOT the Internet.
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It consists of millions of electronic files called Web pages.
A related collection of Web pages is a Web site.
Web sites can be created by businesses, organizations,
and individuals.
Web pages frequently contain hyperlinks.
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It is an application that uses the Internet.
A hyperlink can transport you to another page or site just by
clicking on the hyperlink.
Lesson 2 — The Internet and the World Wide Web
Web Protocols - HTTP
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HTTP is a protocol that defines how messages are
formatted and transmitted.
Web pages are sent in HTTP protocol.
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Every Web site has a unique address called an URL.
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Web servers and Web browsers both can understand HTTP.
The first part of an URL indicates the protocol required to
access the page.
The second part of an URL specifies the IP address or a
domain name.
The top-level domain at the end of the URL indicates the type
of organization or business.
Lesson 2 — The Internet and the World Wide Web
An URL and Its Web Site
This figure shows the
Hamster Dance Web site
in a browser window. The
URL is shown in the
Address Bar of the Web
browser, and that
address is what the user
entered in the browser to
arrive at this site.
HTTP://www.hamsterdance.com
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Lesson 2 — The Internet and the World Wide Web
Web Protocols - HTML
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HTML is a protocol that determines how a Web page is
formatted.
Web pages consist of text coded with HTML markup tags.
The Web browser reads the tags and formats and displays the
page.
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Factors that affect how a page displays include
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Different browsers may interpret certain HTML tags differently.
The type and version of browser being used.
The actual HTML tags being used.
The type and resolution of the monitor being used.
Lesson 2 — The Internet and the World Wide Web
Accessing the Internet
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There are a variety of ways to connect to the
Internet, including
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Through a modem and telephone line.
Through a local area network.
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This requires a network interface card (NIC) in your
computer.
Through high-speed leased lines.
Lesson 2 — The Internet and the World Wide Web
Use a Modem and Phone Line to
Access the Internet
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If your computer has a modem installed and a phone line
connected to it, you can access the Internet by
– Locating and signing up with an ISP.
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An ISP is an Internet Service Provider.
Installing telecommunications software on your computer.
Installing a Web browser on your computer.
Setting up your modem to dial a telephone number supplied
by your ISP.
Having the modem dial out and log in to your ISP. You are
now on the Internet.
Lesson 2 — The Internet and the World Wide Web
Access the Internet via a Network
LAN
This figure shows how the
Internet can be accessed
via a LAN. The computers
on the LAN are able to get
to the Internet through a
high-speed line connected
to the LAN, which is also
connected to the Internet.
High-speed line
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Lesson 2 — The Internet and the World Wide Web
Other Internet Connections
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DSL: Digital subscriber lines
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Cable modem
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Very high-speed access, usually using cable television
lines
WebTV
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Very high-speed connection over standard phone lines
Uses hardware that connects to your television and a
standard phone line
Lesson 2 — The Internet and the World Wide Web
What Is a Browser?
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A browser is a software program that you use to retrieve
information from the World Wide Web and display it in
readable format.
A browser can display text, images, sound, animation,
and video.
You navigate the Web by using your mouse to point to
and click on hyperlinked words and images displayed in
your browser.
The two most popular browsers are Microsoft Internet
Explorer and Netscape Navigator.
Lesson 2 — The Internet and the World Wide Web
Summary
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No one person or organization can claim credit for
the Internet.
Origins of the Internet can be traced to the U.S.
Department of Defense. The original name for the
Internet was ARPANET.
Mosaic was the Internet’s first graphical interface,
or browser.
Lesson 2 — The Internet and the World Wide Web
Summary (continued)
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To connect to the Internet from a business or academic
setting, you probably have a direct connection via a
local area network and a network interface card. For
the home user, the most common type of Internet
connection is with a modem and telephone line.
To connect to the Internet, you need an Internet
connection, telecommunications software, and a
browser.
Other types of Internet connections include ISDN, DSL,
cable modem, and WebTV.
Lesson 2 — The Internet and the World Wide Web
Summary (continued)
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Interoperability means that all brands, models,
and makes of computers can communicate with
each other.
A protocol is a standard format for transferring
data between two devices. TCP/IP is the agreedon international standard for transmitting data.
The domain name identifies a site on the
Internet.
Lesson 2 — The Internet and the World Wide Web
Summary (continued)
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The Web is an application that makes use of the
Internet. Other features of the Internet include
electronic mail, chat rooms, mailing lists, and
newsgroups.
Web pages can be linked through hypertext.
Microsoft Internet Explorer and Netscape
Navigator are two of the most popular Web
browsers.
Lesson 2 — The Internet and the World Wide Web
Summary (continued)
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The HTTP protocol defines how Web messages are
formatted and transmitted.
The Web site address is referred to as the URL, or
Uniform Resource Locator. Every Web page on the
Internet has its own unique address.
A Web page is coded with HTML markup tags. HTML
is another protocol that controls how Web pages are
formatted and displayed.
Lesson 2 — The Internet and the World Wide Web