introduction to computer lec (6)
TRANSCRIPT
Lecture#6
Internet
Internet
• A network of networks, joining many government, university and private computers together and providing an infrastructure for the use of E-mail and other services.
• The largest network of networks in the world.
• Services on Internet:
• Web
• Chat
• File Transfer
• Instant Messaging etc…
History of the InternetHow has the Internet grown?
Today
More than 150 million host nodes
1984
More than 1,000 host nodes
1969
Four host nodes
Evolution of the Internet
• The Internet originated as ARPANET in September 1969 and had two main goals:
5
Allow scientists at different physical locations to share
information and work together
Function even if part of the network were
disabled or destroyed by a disaster
Evolution of the Internet
1969ARPANET becomes
functional
1984ARPANET has
more than 1,000
individual computers linked as
hosts
1986 NSF connects NSFnet to
ARPANET and becomes
known as the Internet
1995 NSFNetterminates its network
on the Internet and
resumes status as research network
1996Internet2 is
founded
Today More than 550
million hosts connect to
the Internet
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Evolution of the Internet
• Many home and small business users connect to the Internet via high-speed broadband Internet service
Cable Internet service
DSL
Fiber to the
Premises (FTTP)
Fixed wireless
Cellular Radio
NetworkWi-Fi
Satellite Internet Service
Evolution of the Internet
• An access provider is a business that provides individuals and organizations access to the Internet free or for a fee
Evolution of the Internet
ISP (Internetservice provider)
Regional ISPs provide Internet
access to a specific geographical area
National ISPs provide Internet
access in cities and towns nationwide
Online service provider (OSP)
Has many members-only features
Popular OSPs include AOL (America
Online) and MSN (Microsoft Network)
Wireless Internet service provider
Provides wireless Internet access to
computers and mobile devices
May require a wireless modem
Evolution of the Internet
• An IP address is a number that uniquely identifies each computer or device connected to the Internet
• A domain name is the text version of an IP address
– Top-level domain (TLD)
• A DNS server translates the domain name into its associated IP address
History of the Internet
Who controls the Internet?
• No onec—cit is a public, cooperative, and independent network
• Several organizations set standards
High-speed
connection
Slow-speed
technology
How the Internet WorksHow can you connect to the Internet?
p. 70 Next
Dial-up accessmodem in your computer uses a
standard telephone line to connect to the Internet
Digital subscriber line (DSL),
cable telephone Internet
services (CATV), cable modem
provide connections using
regular copper telephone lines
Connection is always on—
whenever the computer
is running
Connection must be established
each time you log on.
Slow but inexpensive
The World Wide Web
p. 75
What is the World Wide Web (WWW)?
A worldwide collection of electronic documents
Each electronic document is called a Web page
Also called the Web
Can contain text, graphics, sound, video, and built-in connections
A Web site is a collection of related Web pages
The World Wide WebWhat is a Web browser?
p. 75
MicrosoftInternetExplorer
Netscape
Mozilla
• Program that allows you to view Web pages.
Google Chrome
Safari Opera
The World Wide Web
What is a home page?• The first page that a Web site presents
• Often provides connections to other Web pages
The World Wide Web
What is downloading?
• 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
What is a URL?
Unique address for a Web page
• A web server delivers the Web page to your computer
The World Wide Web
• Tabbed browsing allows you to open and view multiple Web pages in a single Web browser window
The World Wide Web
What is a hyperlink (link)?
Item found elsewhere on same Web page
Different Web page at same Web site
Web page at a different Web site
Built-in connection to another related Web page location
The World Wide Web
What is a search Engine?
• Program used to find Web sites and Web pages by entering words or phrases in it.
• These words or phrases called search text
The World Wide Web
What is a hit?
• Any Web site name that is listed as the result of a search
The World Wide Web
• There are thirteen types of Web sites
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Portal News Informational Business/Marketing
Blog Wiki Online Social Network
Educational
The World Wide Web
Entertainment Advocacy Web Application
Content Aggregator
Personal
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The World Wide WebWhat 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,
Web communities
(Web sites that join
people with similar
interests)
The World Wide WebWhat is a news Web site?
p. 82 Fig. 2-13b
• Contains newsworthy material
• Stories and articles relating to current events, life, money, sports, and weather
The World Wide WebWhat is an informational Web site?• Contains factual information
• Created by organizations and government agencies
The World Wide WebWhat is a business/marketing Web site?• Contains content that promotes products• Allows you to purchase products or services online
The World Wide WebWhat is an educational Web site?
Some companies
offer online training
for employees
Some colleges offer
online classes and
degrees
Offers avenues for formal and informal teaching
and learning
The World Wide WebWhat is an entertainment Web site? Offers an interactive environment featuring music,
video, sports, games, and more
The World Wide WebWhat is an advocacy Web site? Contains content that describes a cause, opinion,
or idea
The World Wide Web
• What is an Social Network Web site?
• A Web site that provides a virtual community for people interested in a particular subject, to simply interact together or to increase their circle of friends such as Facebook, MySpace and LinkedIn.
The World Wide WebWiki• A wiki is a website whose users can add, modify, or delete its
content via a web browser using a simplified markup language or a rich-text editor
The World Wide Web• Blog: A Web site on which an individual or group of
users gives opinions, information, etc. on a regular basis.
The World Wide WebWhat 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• A web application is an application that is accessed over a
network such as the Internet or an intranet .The term may also mean a computer software application that is coded in a browser-supported language. Web application is executable in browsers.
The World Wide Web
• Multimedia refers to any application thatcombines text with:
The World Wide Web
• A graphic is a digital representation of nontext information
• Graphic formats include BMP, GIF, JPEG, PNG, and TIFF
The World Wide Web
• A thumbnail is a small version of a larger graphic
The World Wide Web
• Animation is the appearance of motion created by displaying a series of still images in sequence
The World Wide Web
• Audio includes music, speech, or any other sound
– Compressed to reduce file size
• You listen to audio on your computer using a player
• Streaming is the process of transferring data in a continuous and even flow
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The World Wide Web
• Video consists of images displayed in motion
The World Wide Web
• A plug-in is a program that extends the capability of a Web browser
E-Commerce
• E-commerce is a business transaction that occurs over an electronic network
– M-commerce identifies e-commerce that takes place using mobile devices
• Also called Online Shopping.
E-Commerce
E-commerce
Business-to-
consumer (B2C)
Consumer-to-
consumer (C2C)
Business-to-
business (B2B)
Other Internet ServicesWhat 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 ServicesWhat is an e-mail address? Unique name that consists of a user name and domain
name that identifies the user
Other Internet Services
Protocol: A standard set of rules, regulations andrequirements that allow two electronic devices to connect
to and exchange information with one another.
FTP (File Transfer Protocol) is an Internet standard thatpermits file uploading and downloading with othercomputers on the Internet
Many operating systems include FTP capabilities
An FTP server is a computer that allows users to uploadand/or download files using FTP
Other Internet Services
Telnet
• Telnet is a protocol that allows you to connect to remote computers (called hosts) over a network (such as the Internet).
Other Internet ServicesWhat 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 ServicesWhat is a chat? Real-time typed conversation that takes place on
a computer
Chat room is location on server that permits users to discuss topics of interest
Instant messaging (IM) is a real-time Internet communications service
Other Internet Services
• VoIP (Voice over IP) enables users to speak to other users over the Internet
– Also called Internet telephony