Computer Confluence 7/e

Computer Confluence 7/e Chapter 9Objectives Explain how and why the Internet was created Describe the technology that is at the heart of the Internet Describe the technology that makes the Web work as a multimedia mass medium Discuss the tools people use to build Web sites © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9Objectives (cont.) Discuss the trends that are changing the Internet and the way people use it Discuss some of the most important social and political issues raised by the growth of the Internet Describe various ways that governments restrict access to the Internet © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 ARPANET Pioneers Build an Unreliable Network ... on Purpose The Advanced Research Projects Agency NETwork (ARPANET) is the predecessor to the Internet: Developed at the request of the Department of Defense by a team of visionary computer scientists Launched in 1969 Its peer-to-peer networking philosophy and protocols were copied in other networks in the 1980s Disbanded in 1990, having fulfilled its research mission, but its technology spawned the Internet © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Internet Counting Connections The Internet: an interconnected network of thousands of networks Links academic, research, government, and commercial institutions Connects computers to about every country in the world. Growing too fast to measure its growth Too decentralized to quantify A network with no hard boundaries © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Internet Internet Protocols Transmission Control Protocol/Internet Protocol, TCP/IP… At the heart of the Internet Allows cross-network communication © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Internet TCP breaks messages into packets Each packet has all the information needed to travel from network to network Host systems called routers determine how to route transmissions IP is the address for the packets Each Internet host computer has a unique IP address Each address is comprised of four sets of numbers separated by periods, such as 123.23.168.22 © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Internet Internet Addresses The host is named using DNS (domain name system), which translates IP addresses into a string of names Top-level domains include: .edu - educational sites .com - commercial sites .gov - government sites .mil - military sites .net - network administration sites .org - nonprofit organizations © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Internet The Internet Ad Hoc Committee recently created seven additional top-level domain names: .aero Air transport organizations .biz Businesses .coop Cooperative businesses such as credit unions .info Information services .museum Museums .name Personal registration by name .pro Licensed professionals, including lawyers, doctors, and accountants © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Internet An email address includes: username@hostname.sub.dom username is the person’s “mailbox” hostname is the name of the host computer and is followed by one or more domains separated by periods: host.domain host.subdomain.domain host.subdomain.subdomain.domain © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Internet Internet Access Options Direct (Dedicated) Connection Computer has its own IP address and is attached to a LAN No need to dial up Files are stored on your computer Quick response time Dialup Connection Limited connection using a modem Full access dialup uses SLIP or PPP via modem © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Internet Broadband Connections DSL Service Newer, faster, and cheaper than ISDN Can share phone line with voice traffic Cable Modem Connection Allows Internet connections using shared TV cables Can exceed DSL speeds Carries increased privacy and security risks © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Internet Satellite Connection Provides connection using DirecTV satellite dishes Wireless Broadband Connection Allows multiple computers to connect to a base station using short-range radio waves. Internet Service Providers (ISPs) Local ISPs provide connections through local telephone lines National ISPs offer connections on a nationwide scale © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Internet Internet Servers E-mail server acts like a local post office for a particular Internet host—a business, an organization, or an ISP File servers are common within LANs Also used to share programs, media files, and other data across the Internet File transfer protocol (FTP) allows users to transfer files Download files from remote servers to their computers Upload files to remote computers File compression saves storage space on disk and saves transmission time when files are transferred through networks © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Internet Application server stores applications—PC office applications, databases, or other applications Makes them available to client programs that request them Might be housed at an application service provider (ASP), a company that manages and delivers application services on a contract basis Web server stores Web pages and sends pages to client Web browsers © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Web Web Protocols: HTTP and HTML WWW is a distributed browsing and searching system developed at CERN and designed to give Internet documents unique addresses HTML was created for encoding and displaying documents An HTML document includes code that determines the format, layout, and structure of a Web document © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Web Browser software was built for viewing documents from remote locations The Web is built around a naming scheme that allows every information resource on the Internet to be referred to using a uniform resource locator, or as it’s more commonly known, a URL. A typlical URL looks like this: http://weatherunderground.com/satellite/vis/1k/US.html/ © 2006 Prentice-Hall, Inc.

By expanding the number of people who have the power to transmit knowledge, the Web might trigger a power shift that changes everything. —Howard Rheingold, Virtual Communities Computer Confluence 7/e Chapter 9 Inside the Web Publishing on the Web Programs that convert document format features into HTML codes: Microsoft Word, PowerPoint, FileMaker Web authoring programs: Macromedia Dreamweaver, Adobe GoLive, Microsoft FrontPage © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Web • Tables • Frames • Forms • Downloadable audio and video • Streaming audio and video • Real-time live audio or video • 3-D environments From Hypertext to Multimedia Typical Web pages can contain: © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Web • Windows Media Player • QuickTime • Shockwave/Flash • RealPlayer • Adobe Reader and Acrobat (Adobe) Plug-ins are software extensions that add new features: © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Web Dynamic HTML Adds more programming power to HTML by allowing code to automatically modify itself under certain circumstances JavaScript Scripting language for enhancing HTML Web pages © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Web • Offer contact information • Think like a publisher and a multimedia designer • Test before you publish • Think before you publish • Keep it current Rules of Thumb: Weaving Winning Web Sites Start with a plan Write for the Web Keep it simple Keep it consistent Make it obvious Keep it small Keep it honest © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Web Dynamic Web Sites: Beyond HTML Java Full-featured, cross-platform, object-oriented programming language Java Applets Small Java programs Automatically downloaded onto your client computer Can run on any platform ActiveX Collection of programming technologies and tools for creating controls or components— Similar in many ways to Java applets © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside the Web WML (Wireless Markup Language) Helps create Web documents containing stock quotes, phone numbers, and other small nuggets of information XML (Extensible Markup Language) Will replace HTML plus provide additional features and extensions XHTML A sort of cross between HTML and XML VRML (Virtual Reality Modeling Language) Creates 3-D virtual worlds SMIL (Synchronized Multimedia Integration Language) Makes it possible to link time-based streaming media Sounds, video, and animation can be tightly integrated © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside Web Applications Search Engines Designed to make it easier to find information on the Web Web Crawlers or Spiders Software robots that systematically search the Web Some search engines use keywords and Boolean logic to conduct searches Other search engines conduct searches using a hierarchical directory or subject tree © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside Web Applications Meta-Search Engines (such as MetaCrawler, OneSeek, and Apple’s Sherlock) Conduct parallel searches using several different search engines and directories © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside Web Applications Portals Web entry stations that offer quick and easy access to a variety of services Consumer portals include search engines,e-mail services, chat rooms, references, news and sports headlines, shopping malls, and other services Corporate portals on intranets serve the employees of particular corporations Vertical portals are targeted at members of a particular industry or economic sector © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside Web Applications • Handle URLs with care • Get to know your search engines • If you’re in a hurry, dispense with frills • Organize your favorite bookmarks • Be selective • Protect your privacy • Be conscious of cookies • Shop with bots • Shop smart • Remember why you’re there • Think before you publish Rules of Thumb: Working the Web © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside Web Applications Push Technology: Notifications and Alerts The Web was built with pull technology Browsers on client computers “pull” information from server machines Browser asks for information With push technology, information is delivered automatically to the client computer New product descriptions Automatic software upgrades Updated news © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside Web Applications Peer-to-Peer and Grid Computing Peer-to-Peer (P2P) Computing Users share music, movies, and other files without going through a central directory Grid Computing Anyone can plug in from anywhere and rent processing power and software from anywhere on the Net © 2006 Prentice-Hall, Inc.

Our customers are moving atInternet speed. They need us to respond at Internet speed. —Laurie Tucker, Federal Express vice president Computer Confluence 7/e Chapter 9 Inside Web Applications Intranets, Extranets, and Electronic Commerce Intranets: self-contained intra-organizational networks that offer e-mail, newsgroups, file transfer, Web publishing, and other Internet-like services Firewallsprevent unauthorized communication and secure sensitive internal data © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside Web Applications Extranets: private TCP/IP networks designed for outside use by customers, clients, and business partners of the organization which owns the extranet Electronic data interchange (EDI): a decade-old set of specifications for ordering, billing, and paying for parts and services over private networks Electronic commerce involves business transactions through electronic networks Business-to-business (B2B) e-commerce: transactions that involve businesses providing goods or services to other businesses Business-to-consumer (B2C) e-commerce: transactions that take place on the Internet because consumers don’t have access to an extranet © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 Inside Web Applications Web Services Web services involve new kinds of Web-based applications that can be assembled quickly using existing software components Examples: Plug a shopping cart component into an existing Web site Design applications that can be accessed through a variety of Web-enabled devices © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 The Evolving Internet Internet2 and the Next Generation Internet Internet2 was launched by the government and various corporations in 1998 to provide faster network communications for universities and research institutions Next Generation Internet (NGI) will consist of a nationwide web of optical fiber integrated with intelligent management software to maintain high-speed connections © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 The Evolving Internet Internet Issues: Ethical and Political Dilemmas Filtering software to combat inappropriate content Digital cash to make online transactionseasier and safer Encryption software to prevent creditcard theft Digital signatures to prevent e-mail forgery Access and Censorship The Digital Divide © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 The Evolving Internet Cyberspace: The Electronic Frontier Science fiction writers suggest that tomorrow’s networks will take us beyond the Internet into an artificial reality that has come to be known as cyberspace Today’s computer networks are still light years from these futuristic visions © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9 The Evolving Internet Inventing the Future: The Invisible Information Infrastructure Vint Cerf, one of the Internet’s founders, thinks the Internet is headed for space–the InterPlaNet project Tim Berners-Lee, the inventor of the Web, is planning a Semantic Web, a Web full of data that is meaningful to computers as well as humans A variety of Internet appliances, network computers, set-top boxes, PDAs, mobile phones, and other devices connected to the Internet in offices and homes © 2006 Prentice-Hall, Inc.

Computer Confluence 7/eChapter 9Lesson Summary The Internet is a network of networks that connects all kinds of computers around the globe and uses standard protocols to allow Internet communication to occur No single organization owns or controls the Internet You can connect to the Internet in several ways that provide different degrees of access to Internet services Most Internet applications are based on the client/server model The Web uses a set of protocols to make a variety of Internet services and multimedia documents available to users through a simple point-and-click interface © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9Lesson Summary (continued) In addition to Web sites, a variety of applications are built on the protocols of the Internet and the Web. For example, people who use the Web depend on search engines to find the information they need Peer-to-peer computing was popularized by music sharing services, but its applications go beyond music sharing Many businesses are exploring ways to apply P2P technology Grid computing goes beyond P2P computing by enabling people to share processor power E-commerce is built on Internet technology © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e Chapter 9Lesson Summary (continued) Businesses use the Internet and the Web for business-to-business and business-to-customer communication Many businesses have private networks, called intranets, based on Internet technology Extranets are also private networks, based on the same technology that enables businesses to connect with their partners As the Internet grows and changes, issues of privacy, security, censorship, criminal activity, universal access, and appropriate Net behavior are surfacing © 2006 Prentice-Hall, Inc.

Computer Confluence 7/e