Transcript Chapter 02

Chapter 2
The Internet and World Wide Web
The Internet
What are some services found on the Internet?
E-mail
Web
File transfer
1.
2.
3.
Chat
5. Message board
6. Instant messaging
(AIM, MSN, Yahoo, ICQ)
4.
(1)
(3)
(2)
p. 2.02 Fig. 2-1
(4)
(5)
(6)
History of the Internet
How did the Internet originate?
 ARPANET: Networking project by Pentagon’s Advanced
Research Projects Agency (ARPA)
---To allow scientists at different locations to share information
---can function even if part of network were destroyed by a disaster
 ARPANET became functional in September 1969.
 Four main computers: UCLA, UCSB,Stanford,UU
p. 2.02
History of the Internet
How has the Internet grown?
Today
More than 150 million host nodes
1984
More than 1,000 host nodes
1969
Four host nodes
p. 2.03
History of the Internet
Who controls the Internet?


No one — it is a public, cooperative, and
independent network
Several organizations set standards
c
c
World Wide Web
Consortium (W3C)
 Oversees research, sets
standards and guidelines
p. 2.04
Internet2 (I2)
 Internet-related research and
development project
 Develops and tests advanced
Internet technologies
How can you connect to the Internet?
Dial-up access
modem in your computer uses a standard telephone line
to connect to the Internet.
2. Integrated Services Digital Network (ISDN)
1.
replaced by
3. Digital subscriber line (DSL)
provide connections using regular copper telephone lines.
4. Cable Modem
taking advantage of unused bandwidth on a cable
television network.
How can you connect to the Internet?
Dial-up
DSL
Cable TV
Speed
56 Kbps
128 Kbps to
1.544 Mbps
200Kbps~1.5Mbps
or more
Price
$6~$20/
month
$20~$50/
month
$20~$50/
month
Connection Establish
connection each
time you log on
Evaluation
Slow but
inexpensive
http://www.ispcomparison.net/
always on—whenever the computer
is running
High speed but cost about twice
as much as dial-up
How the Internet Works
What are the ways to access the Internet?
1. Internet Service Provider (ISP) Regional ISP:
National ISP : AT&T and EarthLink
provide: internet access (dial-up,DSL, cable)
2. Online Service Provider (OSP)
like AOL and MSN
provide: internet access and many members-only
features
3. Wireless Internet Service Provider (WISP)
like AT&T wireless and Vorizon wireless
provide: internet access
p. 2.06 Fig. 2-2
How the Internet Works
How might data travel the Internet using a
telephone line connection?
Step 1.
Request
data
from a
server on
Internet
Step 8.
Server sends
data back to
you
Step 3.
Data travels
through
telephone
lines to a
local ISP
Step 2. Modem
converts digital
signals to analog
signals
Step 7.
National ISP
passes data to
local ISP
p. 2.07 Fig. 2-3
Step 4.
Data passes
through
routers
Step 5. Regional
ISP uses leased
lines to send data
to a national ISP
Step 6.
National ISP
routes data
across the
country
What Is the World Wide Web?
The internet is a network of
computer networks
worldwide
The web is a tool used to
retrieve information
published on the internet
To navigate the web we use a
browser such as Netscape or
internet explorer(IE)
Internet Software:
The Client-server Partnership
Two pieces of software that work together
Client: software application on user’s computer
Client retrieves, displays information for user
Server: stores and sends information to clients as requested
The World Wide Web
What is a Web browser?

Program that allows you to view Web pages
Microsoft
Internet
Explorer
Netscape
Mozilla
p. 2.09
Firefox
Internet Addresses
What is a URL (Uniform Resource Locator)?
Unique address for a Web
page
A web server delivers the
Web page to your computer
p. 2.10 Fig. 2-8
The World Wide Web
What is downloading?


p. 2.10
The process of a computer receiving information
Depending upon connection speed, downloading can
take from a few seconds to several minutes
The World Wide Web
How can you establish a connection and start the
Web browser?
Step 2.
If necessary,
connect to the
Internet
Step 1.
Click the Web browser
program name
Step 3.
Connection to the
Internet occurs, and a
home page displays
p. 2.09 Fig. 2-6
The World Wide Web
How do handheld computers and
cellular telephones access the Web?
p. 2.10 Fig. 2-7

Must be Web-enabled

Use a microbrowser
that displays Web
pages that contain
mostly text
How the Internet Works
What is a domain name?

Text version of Internet protocol (IP) address

Number that uniquely identifies
each computer or device
connected to Internet
Domain name:www.google.com
IP: 64.233.161.99
p. 2.08 Figs. 2-4 – 2-5
Keeping the Web Straight: Document Addresses
Address format: Eg., Http://www.cs.gsu.edu/~xfu1/1010.html
Address must be exact, i.e. Upper and lower case letters make
a difference
.Edu, .Com, .Org, .Gov, ~
HTTP: hypertext transfer protocol
Document type for all web documents
HTML: hypertext markup language
Language for creating web documents
How to Check your IP address
 Check your own IP address
•
•
Start ---all programs ---Accessories—Command Prompt
Type “ ipconfig /all”.
 Check what is the IP address
• Start ---all programs ---Accessories—Command Prompt
• Type “ping www.google.com”
p. 2.08 Figs. 2-4 – 2-5
Hypertext Links
Highlighted words or text
in a WWW document
Previous page
Moves you to a place
within same document, or
to a web page elsewhere
www.student.gsu.edu/~xfu1/1010.html
What Is a Web Site?
http://www.library.utoronto.ca
an electronic document stored on a web server
uses HTML (Hypertext Markup Language)
may include text, sound, animation, images
usually has links to other Web pages or different
parts of the same Web site
What Is a Home Page?
The first web page you see when you
access a web site
Usually provides means of moving
to other areas at that web site
(directory, table of contents)
Who Provides Internet Information?

Non-profit: governments, universities,
libraries, non-profit groups

Commercial information providers

Self-publishers (personal home pages)

Only a fraction of what is available is on the web
Using the World Wide Web
Advantages
• Allows
you to browse a
wide variety of internet
sources
Disadvantages
•
•
•
•
Instantaneous
connections to internet
sites world wide
•
•
Connections can be slow or busy
No standard methods of
organization
Out-of -date materials may not be
removed
Contents can be (maliciously) altered
Sites can simply be moved/removed
What Affects the Speed of Transmission?

Phone lines are “slower” than ethernet wires
Speed of modem: speed of data transmission (BPS)
Modems transmit at 28,800, 33,600 and 56k baud

Traffic on the internet
 The power of your PC

The data being transmitted
Error Messages Do Happen
An error message can appear in a
window on your screen,
because
The URL may be incorrect
The site may have “moved”
The communication lines may be busy
SO retype the URL or try again later
IE Menu Bar
FILE: for working with files (similar to word processing)
EDIT: for editing page content and setting preferences
VIEW: for options on viewing page content
Favorites: Save your favorite websites
Tools: configuration your IE
HELP:
IE Toolbar = Quick Navigation
back forward
refresh home
history
Back and Forward - for short jaunts Tool bar customize:
Refresh - get current page again
1. Let the mouse point to
toolbar
Home - go back to the first screen
2. click right button of
that appears after logging on
mouse
Search - access to internet search
3. Click “customize..”
engines
History-the web sites visited before
Assignment 1


Satisfying the requirement
Concise and clear description and explanation
A Brief Word on Searching
There are four main ways to find information on the
internet:
Using an address (URL)
Net surfing (jumping from link to link)
Using subject directories like yahoo
Using search engines like Google
Try Searching
Search engines:
1.
2.
3.
Open http://www.google.com
Click “Advanced Search ”
Input “computer”,
What is a hit?
-- Any Web site name that is listed as the result of a search
The World Wide Web
What is a search engine?

Program used to find
Web sites and Web
pages by entering
words or phrases
called search text

Also called a keyword
The World Wide Web
What is a subject directory?


Search tool with organized set of topics and subtopics
Lets you find information by clicking links rather than
entering keywords
The World Wide Web
What are the eight basic types of Web sites?
Portal
 News
 Informational
 Business/marketing

Educational
 Entertainment
 Advocacy
 Personal

The World Wide Web
What is a portal?

A Web site that offers a variety of services from one,
convenient location, usually for free

Searching, sports, e-mail, news, weather, auctions,
Example:
1. open “maps.yahoo.com”
2. Click “Driving Directions”
3. In A,
Input “34 peachtree street”
Input “atlanta,30303”
4. In B,
Input your home address
The World Wide Web
What is a news Web site?


Contains newsworthy material
Stories and articles relating to current events, life,
money, sports, and weather
The World Wide Web
What is an informational Web site?


Contains factual information
Created by organizations and government agencies
The World Wide Web
What is a business/marketing Web site?


Contains content that promotes products
Allows you to purchase products or services online
The World Wide Web
What is an educational Web site?

Offers avenues for formal and informal teaching
and learning


Some companies
offer online training
for employees
Some colleges offer
online classes and
degrees
The World Wide Web
What is an entertainment Web site?

Offers an interactive environment featuring music,
video, sports, games, and more
The World Wide Web
What is an advocacy Web site?

Contains content that describes a cause, opinion,
or idea
The World Wide Web
What is a personal Web site?


Web page maintained by private individual
Reasons: sharing life experience with the world
or job hunting
The World Wide Web
What is multimedia?

Application integrating text with other media elements





Graphics
Animation
Audio
Video
Virtual reality
The World Wide Web
What graphics formats are used on the Web?
BMP
JPEG or JPG
PNG
(pronounced JAY-peg)
(pronounced ping)
GIF
(pronounced JIFF)
PCX
TIFF
The World Wide Web
What is a thumbnail?

Small version of a larger
graphic image —used to
improve Web page display
time
c

Usually click
on thumbnail to
display larger
image
The World Wide Web
What is audio?

Music, speech, or any other sound

Individual compressed sound files
that you download from the Web to
your computer


Common Web audio file formats are
MP3, WAV, WMA (Windows Media
Audio), MPEG, RealAudio, and
QuickTime
Once downloaded, you can play
(listen to) the contents of the files
The World Wide Web
What is streaming audio?

Transfers data in a
continuous and even flow

Enables you to listen
to the sound as it
downloads to your
computer

Radio stations use
streaming audio to
broadcast over the Web
The World Wide Web
What is video?


Consists of full-motion images with sound
played back at various speeds
MPEG (Moving Pictures Experts Group)
is popular video compression
standard
The World Wide Web
What is virtual reality (VR)?


Use of computers to simulate real or imagined
environment
Appears as a three dimensional (3-D) space

Used for games and many
practical applications
The World Wide Web
What are plug-ins?


Programs that
extend the
capability of
a browser
You can
download many
plug-ins at no
cost from various
Web sites
Plug-in Application
Web Address
Acrobat Reader
www.adobe.com
Flash Player
macromedia.com
Liquid Player
liquidaudio.com
QuickTime
apple.com
RealOne Player
real.com
Shockwave Player
macromedia.com
Windows Media Player
microsoft.com
Electronic Commerce
What is e-commerce?


Short for electronic commerce
Business transaction that occurs over
the Internet
Business to consumer (B2C)
Sale of goods to general public
Consumer to consumer (C2C)
One consumer sells directly to another
Business to business (B2B)
Business providing goods and
services to other businesses
Other Internet Services
What is e-mail?


Short for electronic mail
The transmission of messages and files via a computer
network




Messages can consist of simple text or can contain attachments,
such as documents, graphics, or audio/video clips
Internet access providers usually provide an e-mail program
Some Web sites—such as MSN Hotmail and Yahoo!—provide
free e-mail services
One of the original services on the Internet
Other Internet Services
How do you send an e-mail message?
Step 2.
Step 1.
Click the New Mail Message button
Start an e-mail
program
(Microsoft
Outlook, for
example)
Step 3.
Enter the recipient’s
e-mail address, the
subject, and the
message
Step 5.
The recipient opens the
message
Step 4.
Click the Insert file button if
you want to attach a picture, for
example, and click Send
Other Internet Services
How does an e-mail message travel?
Step 1.
Using e-mail
software, you
create and send
message
Step 2.
Your software
contacts software
on your ISP’s
outgoing mail
server
Step 4.
When recipient uses
e-mail software to check
for e-mail messages, the
message transfers from
incoming mail server to
recipient’s computer
Step 3.
Software on outgoing mail server
determines best route for data and sends
message, which travels along Internet
routers to recipient’s incoming mail server
Other Internet Services
What is a mailing list?

Group of e-mail addresses
given a single name

When a message is sent
to the mailing list,
everyone on the list
receives the message

To add your name to a mailing
list you must subscribe to it; to
remove your name you must
unsubscribe
Other Internet Services
What is FTP?

File Transfer Protocol—Internet standard that allows
you to upload and download files with other computers
on the Internet
Netiquette
What is netiquette?

Code of acceptable behaviors users should follow while
on the Internet
Golden Rule: Treat others as
you would like them to treat you.
Web Publishing
What is Web publishing?

Development and maintenance of Web pages
Step 2.
Step 1.
Plan the
Web site
Analyze and
design the
Web site
Step 3.
Create the
Web site
Step 5.
Maintain
the Web site
Step 4.
Deploy the
Web site
Summary of the Internet and World Wide Web
History of the Internet
Other Internet services
How to access and connect
to the Internet
Netiquette
The World Wide Web
Web publishing
Electronic commerce
Chapter 2 Complete