© 2013 by the mcgraw-hill companies, inc. all rights reserved. chapter 5a the internet
TRANSCRIPT
© 2013 by the McGraw-Hill Companies, Inc. All rights reserved.
Chapter 5AChapter 5A
The InternetThe Internet
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Learning ObjectivesLearning Objectives5.15.1 Describe two reasons for the Internet’s Describe two reasons for the Internet’s
creationcreation5.2 5.2 Identify six major services you can access Identify six major services you can access
through the Internetthrough the Internet5.3 5.3 Explain how to use a browser, discuss ways to Explain how to use a browser, discuss ways to
search for information, and list three types of search for information, and list three types of social media programs or sitessocial media programs or sites
5.45.4 Identify how the Internet can be useful in a Identify how the Internet can be useful in a school or educational settingschool or educational setting
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Internet HistoryInternet History• InternetInternet: a global communications system that links : a global communications system that links
together thousands of networkstogether thousands of networks• ARPANETARPANET:: a Defense Department network linking a Defense Department network linking
computers at universities and defense contractorscomputers at universities and defense contractors• NSFnetNSFnet: : A higher-capacity network created by the A higher-capacity network created by the
National Science Foundation (NSF)National Science Foundation (NSF)• BackbonesBackbones: : Central network structuresCentral network structures
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Internet ServicesInternet Services• Connects thousands of networks and hundreds of Connects thousands of networks and hundreds of
millions of users around the worldmillions of users around the world• No central ownership or controlNo central ownership or control
– Guidelines and standards Guidelines and standards (e.g., the Internet Society, (e.g., the Internet Society, World Wide Web Consortium)World Wide Web Consortium)
– Free expressionFree expression– Open to anyone who can Open to anyone who can
access itaccess it
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Internet ServicesInternet Services• Includes:Includes:
– World Wide WebWorld Wide Web– Electronic mailElectronic mail– Chat and instant messagingChat and instant messaging– File transfer protocolFile transfer protocol– Peer-to-peerPeer-to-peer– Voice over Internet ProtocolVoice over Internet Protocol
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World Wide WebWorld Wide Web• Created in 1989 at CERN Created in 1989 at CERN • Evolution of the WebEvolution of the Web
– Web 1.0Web 1.0: : from it’s creation through the early 2000s; the from it’s creation through the early 2000s; the focus was on providing information focus was on providing information
– Web 2.0Web 2.0: : from middle 2000s into around the middle from middle 2000s into around the middle 2010s; sites feature user-generated content 2010s; sites feature user-generated content
– Web 3.0Web 3.0: : The next phase of activity that is expected to The next phase of activity that is expected to occuroccur
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Electronic MailElectronic Mail• A system for exchanging A system for exchanging
messages through a messages through a computer networkcomputer network
• One of the first uses of One of the first uses of the Internetthe Internet
• Data files can be Data files can be attachedattached
• Spam: unwanted Spam: unwanted messages that can be messages that can be managed with filtering managed with filtering toolstools
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Chat and Instant MessagingChat and Instant Messaging• ChatChat: : Communication in real time via softwareCommunication in real time via software
– Internet Relay Chat (IRC)Internet Relay Chat (IRC): : Early method of chat Early method of chat – Chat channels are typically created by topicChat channels are typically created by topic
• Instant messaging (IM)Instant messaging (IM): : A type of chat software that A type of chat software that restricts participation to specific usersrestricts participation to specific users– Buddy list Buddy list - list of other users with whom they want to chat- list of other users with whom they want to chat– Software may be stand-alone or embedded in other Software may be stand-alone or embedded in other
programs programs
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File Transfer ProtocolFile Transfer Protocol• File transfer protocol (FTP)File transfer protocol (FTP):: An Internet service that An Internet service that
houses collections of files on an FTP serverhouses collections of files on an FTP server– Can be public Can be public – Files may be retrieved with a common Web browser or Files may be retrieved with a common Web browser or
with client software with client software – Files available on FTP sites include weather maps, Files available on FTP sites include weather maps,
downloadable software and program upgradesdownloadable software and program upgrades
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Peer-to-PeerPeer-to-Peer• Peer-to-peer (P2P)Peer-to-peer (P2P):: File transfer design that uses a File transfer design that uses a
distributed network that does not require a central distributed network that does not require a central serverserver– Software lets a user’s computer identify other computers Software lets a user’s computer identify other computers
in the distributed network and access them directlyin the distributed network and access them directly– Allow people to share files of all types directlyAllow people to share files of all types directly– Used for both legitimate sharing and unauthorized copying Used for both legitimate sharing and unauthorized copying
of copyrighted worksof copyrighted works
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Voice Over Internet ProtocolVoice Over Internet Protocol• Voice over Internet Protocol (VoIP)Voice over Internet Protocol (VoIP) service: service:
translates analog voice signals into digital data and translates analog voice signals into digital data and uses the Internet to transport the datauses the Internet to transport the data– Can connect to telephone networks and digital sources Can connect to telephone networks and digital sources – Users can lease a telephone number in another countryUsers can lease a telephone number in another country– Quality of VoIP calls depends on the quality of the network Quality of VoIP calls depends on the quality of the network
connectionconnection
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The Internet at HomeThe Internet at Home• Web browserWeb browser• Search enginesSearch engines• GamesGames• Radio and televisionRadio and television• Social media softwareSocial media software
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Web BrowserWeb Browser• Software that enables users to access the World Software that enables users to access the World
Wide WebWide Web• WebWeb pagespages: : Documents for Web browsersDocuments for Web browsers
– HypertextHypertext: document text that links to other objects: document text that links to other objects– HTMLHTML: contains instructions for browsers to interpret: contains instructions for browsers to interpret
• Hypertext links Hypertext links : Encoded words or pictures that, : Encoded words or pictures that, when clicked on, take the user to another locationwhen clicked on, take the user to another location
• URLsURLs: : Format for hyperlinks that identifies each Format for hyperlinks that identifies each object on the Web and how it should be retrievedobject on the Web and how it should be retrieved
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Web BrowserWeb Browser• HTTPHTTP : : defines the exact way in which data is defines the exact way in which data is
formatted and transferred back and forth between formatted and transferred back and forth between browser and serverbrowser and server– HTTP is not secure HTTP is not secure
• HTTPSHTTPS : : adds data encryption and Web site identity adds data encryption and Web site identity verificationverification– Secure Web sites obtain a digital certificate from a Secure Web sites obtain a digital certificate from a
certificate authoritycertificate authority
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Search Engines and GamesSearch Engines and Games• Search enginesSearch engines : a combination of hardware and : a combination of hardware and
software that constantly crawl through the Web’s software that constantly crawl through the Web’s contents, finding new informationcontents, finding new information– Popular search engines include Google and BingPopular search engines include Google and Bing
• GamesGames– Thousands of games are available for modern PCs and Thousands of games are available for modern PCs and
game consolesgame consoles– The Internet allows people to play with and against one The Internet allows people to play with and against one
another onlineanother online
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Radio and TelevisionRadio and Television• Many viewers can go online to watch their favorite Many viewers can go online to watch their favorite
showsshows• Radio channels, including local radio stations, also are Radio channels, including local radio stations, also are
available onlineavailable online• Many people create their own audio and video Many people create their own audio and video
broadcasts and save them as online files, known as broadcasts and save them as online files, known as podcastspodcasts– available for download available for download
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Social Media SoftwareSocial Media Software• Social media softwareSocial media software:: Programs and utilities that Programs and utilities that
make it simple for people to share common interests make it simple for people to share common interests and informationand information– Social networkingSocial networking Web sites: designed to connect people Web sites: designed to connect people
directlydirectly– Anyone can create a personal information layout, or Anyone can create a personal information layout, or
profileprofile• Twitter: specializes in the sharing of micro-status Twitter: specializes in the sharing of micro-status
messages, called tweets, of up to 140 charactersmessages, called tweets, of up to 140 characters
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Internet at SchoolInternet at School• An education helper:An education helper:
– EdutainmentEdutainment programs: programs: Software that attempts to Software that attempts to be both educational andbe both educational andentertainingentertaining
– Standardized testing via Standardized testing via Web-based test programsWeb-based test programs
• Online researchOnline research• Online classes and universitiesOnline classes and universities