Chapter 02 CLASS 2

7/30/2019 Chapter 02 CLASS 2

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Introduction to informationtechnology

Recommended text book:introduction to computers by

Peter Norton 6 th edition


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Course Outline : Chapters

Introducing computer systems Presenting the internet Interacting with your computer

E-mail and Other Internet Services Alternative input devices Video and Sound Processing data Network Basics Data communications The Basics of Information Systems


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Chapter 02

Presenting the internet


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Internet is a global communication systemthat connects thousands of individualnetworks

Its an essential part of computer!


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History

1969 ARPANET ARPA ..advanced research project agency

of U.S department of defense Goal? Survive a nuclear attack or natural

disaster like earthquake

Secondly allow people in remote areas toshare computing resources


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Host computers?


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The network expanded rapidly and jumped toEurope in 1973

In 1980s NSF joined the group and they

establish five supercomputer centers for academic research programs

NSF created another network called NSF-net.

Together ARPANET, NSF-net and other networks called the internet No commercial traffic allowed


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.

1n 1990s ARPANET was shut down NSF-net was discontinued in 1995

The commercial internet backboneservices replace them


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internet major services

The world wide web Electronic email

Chat instant messaging Online services and more


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The world wide web

This service was created in 1989 to incooperate billions of documents all storedat different places


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How the web works

Hypertext system HTTP protocol

A hypertext document or web page is aspecially encoded file that uses thehypertext markup language or HTML.

Web site? Web severs or internet host computers


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Web browsers

A software application designed to find thehypertext document and open it to theusers computer Read and translate the HTML

There are many point-and-click webbrowsers examples?


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URLs

Uniform resource locator it is the global address of documents and

other resources on the World Wide Web .
http://www.webopedia.com/TERM/W/World_Wide_Web.htmlhttp://www.webopedia.com/TERM/W/World_Wide_Web.html


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Helper applications Plug-ins Enhance a browsers functionality Streaming audio and video Sends the file in small chunks Chunks downloaded while others play


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Flash

Most commonly used multimedia player made by Macromedia

Enables to design or create high qualityanimation or video that plays directlywithin the browser.


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Using a Browser And The WWW

Browser starts on the home page Navigating the web

Enter a URL in the browser Click a link Links are typically blue underlined words Image maps are picture links


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Searching the Web

The two most common Web-based searchtools are

Directories Categorize the Internet E.g. yahoo search engine

Search engines Find sites by keyword E.g. Google


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Search techniques

Quote the exact phrase Use the keyword AND,OR and NEAR

(these are called Boolean operators) Avoid common words Use the sites advanced tools


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E-mail and Other InternetServices


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E-mail

Advantages over past communicationmediumLess expensiveFaster to communicateEasy to access

Ability to attach data or filesMessage can be send to multiple peopleat the same time.


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Configuring e-mail e-mail clients read and send e-mail Need an e-mail program and an Internet

connection Need name of mail server Need username and password

Hotmail and Yahoo are online clients No configuration needed


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Mail server :many mail servers use POPprotocol .

Listserv system: was the first electronicmailing list software application. themessages sent can be seen by the entiregroup examples?


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Using an email program

e-mail addresses Unique address Allows sending and receiving [email protected]

Listserv Lists of e-mail addresses Each address gets the e-mail


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Advantages of web-based E-mailservices

cost :free email accounts are provided byweb-based email services examplehotmail

Easy to use Accessibility :you do not need to log on to

your specific ISPs account .


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Other features of internet

News Public bulletin board called news Thousands of topics available

Messages are called threads Users can create threads Users can comment on threads

Need a news reader programa thread is a sequence of responses to aninitial message posting.


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NNTP:networknews transfer protocol


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Newsgroup domains

News group begins with a domain followedby one or more words example alt.foodwhere alt is the domain see page 82


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Many internet newsgroups are there Usenet: many newsgroups are part of a

system called Usenet:Usenet is a worldwide distributed Internet

discussion system
http://en.wikipedia.org/wiki/Internethttp://en.wikipedia.org/wiki/Internet


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Features of internetFTP

File Transfer Protocol (FTP) Copies files from a remote computer

FTP site often called archives FTP server Public archive server :allows anyone to

make copy of their files exampleMicrosoft.com


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Many companies host their own ftp sitesExamples computer hardware and software

companies. One way to find files is through Archie

search tools


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Other Internet Features

Internet Relay Chat (IRC) Real time communication system Multi-users with many channels (rooms) Channels are dedicated to a topic All users can read the comments


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Instant messaging (IM) Private, real-time communication Message sent only to listed users Buddy lists contain IM names


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Other Internet Services

Online services Company that offers access by subscription Banks, games and research America Online offers content and Internet

Give more examples and discuss


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Other Internet Services

Peer-to-peer (P2P) servicesPeers are both suppliers and consumers of

resources, in contrast to the traditional client server model where only servers supply (send),and clients consume (receive). User computers are connected together No centralized organization Users can communicate directlyExample is instant messaging

Users can share files
http://en.wikipedia.org/wiki/Client%E2%80%93serverhttp://en.wikipedia.org/wiki/Client%E2%80%93serverhttp://en.wikipedia.org/wiki/Client%E2%80%93serverhttp://en.wikipedia.org/wiki/Client%E2%80%93serverhttp://en.wikipedia.org/wiki/Client%E2%80%93serverhttp://en.wikipedia.org/wiki/Client%E2%80%93server


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THANK YOU

Documents

Chapter 02 CLASS 2