Transcript m5zn_4836f241122847ax

Chapter 5
Preparatory year
Alimam Islamic university
Chapter 5
Chapter Objectives:
• Explain how the Internet works.
• Describe methods for access the internet.
• Define and differentiate between the internet the World
Wide Web.
• Explain the concept of hypertext.
• Contrast Web browsers and Web servers.
• Explain how search operators can improve Web search
results.
• List the most popular internet services and explain what
they do .
What is the internet
• The internet is a global computer network made up of
thousands of privately and publicly networks .
• Computers can exchange data
• The internet is referred to as cyberspace
• Internet backbone are maintained by network service
providers(NSPs)
How is the Internet Works‫؟‬
• Volunteers maintain the Internet
networks.
• Private and public groups
provide the equipment.
• Network service providers such
as AT&T maintain the Internet
backbone, the main high-speed
routes.
4
INTEROPERABILITY
Interoperability :
• Is the ability to work with the computer even if it is a
different brand and model.
• The reason is the TCP/IP
• TCP/IP supply the standard methods of:
1. Packaging information
2. Transmitting information.
Accessing the internet: going online
• Internet service providers(ISPs)
Companies that provide access to the internet.
• ISPs have several roles and responsibilities:
• Provide and maintaining a connection to the internet .
• Support the Hardware and software needed to service
that connection .
• Protect their site and network from external thearts .
• Online service :
services that are available only to subscribers.
Methods to Access the Internet
• Dial-up access :
– Run over normal telephone lines
– While online, your phone is unavailable for calls
– Speed: 14-56 kbs.
Disadvantage:
– slowest
Advantage:
– cheapest connection
Active modem
Methods to Access the Internet
• Digital subscriber line(DSL):
– Offer faster access speeds than dial-up
– Operates over normal telephone lines.
– Can be used simultaneously with the telephone.
– Average Speed: 1.5 megabits per second.
DSL Modem
Methods to Access the Internet
• Cable Access :
– provides a high-speed Internet connection using a
cable modem
– no phone line is needed ,but a cable modem is
required.
• Satellite access:
- It requires:
1. A satellite dish
2. Phone line and modem for an Internet connection.
9
Methods to access the Internet
• Fiber-optic service (FiOS):
• Provides fast Internet access .
• Fiber-optic lines run directly to users’ homes.
•No modems are required.
10
The Internet and the Web: What’s the
Difference?
• World Wide Web( WWW):
- collection of internet resources .
FTP, audio, video,…….
– Contains billions of documents
– Is a portion of the Internet
– Uses the Internet as a means
to transport information
– Is a separate entity from the
Internet
11
Features of the Internet
• Web page
- Document that may include text, graphics, sound,
animation, and video.
• Web site
- collection of Web pages.
• Web browser
- program that displays Web pages and linked items.
• Home page
- Web page that displays every time the browser is
started.
12
Features of the Internet
• Hyperlinks or links:
- Bring other documents .
• Hypertext
- Move to additional related information.
• Hypertext Markup Language(HTML)
- Create Web pages.
• Extensible
Markup
Language
(XML):
- Reduce the complexity of HTML.
a
13
The Internet and the Web: What’s the
Difference?
• Internet
- Physical connection of network.
• Web
- Application runs on the top of the Internet
architecture.
14
Features of the Internet
•
Web browser:
- Displays a Web document –
and the linked documents.
• Plug-ins:
- Browsers use for extra
features such as sound and
video.
• The most popular browsers
– Mozilla Firefox
– Google Chrome
– Internet Explorer
– Opera
– Safari
15
Features of the Internet
•
–
–
–
Windows Internet Explorer:
Enables to view the World Wide Web contents.
Connects to the Internet.
Receives e-mail and assists with downloading and
transferring files from the Internet
– Displays Web site graphics.
– Plays audio and video files associated with a Web
site.
16
Exploring Internet Services
• Sponsored links:
- Displayed as results at a search engine site.
– Gain from increasing traffic to their Web site
– Placed near the top or on the right side of the search
engine results page .
• History feature:
– History list.
– Recently visited Web pages and sites.
– Internet Explorer tracks sites visited in the last 20 days.
17
Features of the Internet
• Downloading:
- Process of transferring a file to the user computer .
• Uploading:
- Process of transferring a file from the user’s
computer.
• Internet Protocol (IP) address.
- Devices connected to the Internet is given IP .
- Four bytes address.(ex:192.168.2.1)
18
Features of the Internet
• Uniform Resource Locator (URL)
- Identification of an Internet resource’s .
- URL is a unique web site address.
• URL is made up of:
- Hypertext Transfer Protocol (HTTP)
- Domain name.
- Path
- Resource name.
19
Features of the Internet
• Web servers
- Stores web sites.
- Process the requests
- Send the requested documents.
• Ways to access a Web page
– Type a URL into the address bar.
– Click a tab in the browser window.
– Click a hyperlink.
20
Common Top-level Domain Name
Top-Level
Domain Name
Used By
Top-Level
Domain Name
Used By
.com
Commercial
businesses
.mil
Military
.biz
Businesses
.aero
Aviation
.edu
Educational
institutions
.net
Network
organizations
.info
Information
.coop
Cooperative
.gov
Government
agencies
.org
Nonprofit
organizations
.pro
professionals
.museum
museum
21
Finding Information
on the Web
• search engines :
- Web sites with search capabilities .
- Programs that search for keywords.
- Index databases of Web pages.
- Fast information searches.
22
Finding Information
on the Web
• Specialized search engines:
- Index information
• Portals:
- Provide organized subject guide links to topics.
Example of portal:
23
Exploring Internet Services
• Pop-ups:
- Windows that display on
the screen without
being requested.
• Pop-Up Blocker:
- stops these windows from
displaying.
24
Finding Information
on the Web
• Use Web information for schoolwork.
– Access authoritative online sources.
– Locate published works.
– Provide appropriate online and offline reference
citations in your work.
• Internet service
- Set of standards or protocols.
- Identify how computers communicate through the
Internet.
25
Exploring Internet Services
• Electronic mail (e-mail) :
- Sending and receiving messages.
• E-mail attachment:
- A file included with an e-mail message.
E-mail address:
- Unique address.
- consists of a user name, hosting e-mail service, and
the top-level domain.
26
Exploring Internet Services
• Spam:
- Unsolicited e-mails received by users.
- Usually from advertisers.
Spam
27
Exploring Internet Services
• Instant messaging (IM) systems:
– Requires additional software
– Real-time communication.
– Notifies users .
– May be susceptible to—spam
28
Exploring Internet Services
• Internet relay chat (IRC):
- Ability to join chat groups
called channels.
• Social networking:
- Ability to
create large communities
online.
2 channels Xaric, a text-based IRC use on Mac OS
29
Exploring Internet Services
• Copyright laws:
- Protect authors of original works.
- Exceptions to this law is the use of small amounts of
information for educational purposes.
The Copyright Act of 1790 in the
Columbian Centinel
30
Summary
• The Internet is a global computer network.
• The Internet enables computers connected to it
to exchange data.
• Public or private Internet service providers supply
users with access to the Internet.
31
Summary
• The World Wide Web, which is made up of
billions of hypertext documents, uses the
Internet.
• Web browsers display Web documents and give
users the ability to use linked documents.
• A URL is made up of a protocol, a domain, a
path, and a resource name.
32
Summary
• Search engines permit users to search the databases of
the Web.
• Information found on the Web should be critically
evaluated for being reputable and accurate.
33