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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
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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