E-Business Eighth Edition Chapter 8 Web Server Hardware and Software

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Transcript of E-Business Eighth Edition Chapter 8 Web Server Hardware and Software

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  • E-Business Eighth Edition Chapter 8 Web Server Hardware and Software
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  • E-Business, Eighth Edition22 Learning Objectives In this chapter, you will learn about: Web server basics Software for Web servers E-mail management and spam control issues Internet and Web site utility programs Web server hardware
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  • Web Server Basics Chapter topics Basic technologies to build online business Web sites Server software and hardware Utility function software Web server Main job: respond to Web client requests Main elements: hardware, operating system software, Web server software Web site goals followed by site development Perform site estimates Determine hardware and software combination E-Business, Eighth Edition3
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  • Types of Web Sites Web site planning is first step Determine site goals Estimate visitors, types of files Assess existing information technology staff Five Web site categories Development sites: evaluate Web designs Intranets: house internal information Extranets: allow outside party access Transaction-processing sites: commerce site Content-delivery sites: deliver news, histories, summaries, digital content E-Business, Eighth Edition4
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  • 5 Web Clients and Web Servers Client/server architectures Client requests services from server Client computer Uses Web browser software (Web client software) Server computer More memory and larger, faster disk drives Platform neutral Web software Various computers communicate easily, effectively Critical ingredient for rapid spread, widespread Web acceptance
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  • 7 Dynamic Content Server performance affected by: Web page mix and type delivered to client Dynamic page Client Web page content shaped by program Static page Unchanging page retrieved from disk Sometimes stored in Web servers active memory Static versus dynamic page delivery Static page requires less computing power Servers delivering mostly static pages perform better
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  • E-Business, Eighth Edition8 Dynamic Content (contd.) Dynamic content Nonstatic information constructed in response to Web clients request Example: order inquiry with unique customer number Web sites using collection of HTML pages Changed by editing HTML (cumbersome) Specific query-customized pages not allowed Create customized pages on the fly using: Server-side scripting Dynamic page-generation technology
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  • E-Business, Eighth Edition9 Dynamic Content (contd.) Server-side scripting Used by first Web sites providing dynamic pages Also called: Server-side includes Server-side technologies Web server programs create Web pages before sending pages back to client Server-side technologies are slow Large online business Web sites alternative Dynamic page-generation technologies
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  • Dynamic Content (contd.) Dynamic page-generation technologies Examples Microsoft Active Server Pages (ASP) Sun Microsystems JavaServer Pages (JSP) Open-source Apache Software Foundation Hypertext Preprocessor (PHP) Adobe Cold Fusion Dynamic Web page creation Server-side scripts mix with HTML tagged text Java servlets Server-side programs created using Java programming language (Sun) E-Business, Eighth Edition10
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  • E-Business, Eighth Edition11 Dynamic Content (contd.) Dynamic page-generation technologies (contd.) Popular tools to generate dynamic Web pages and make them interactive AJAX (asynchronous JavaScript and XML): creates interactive Web sites looking like applications Ruby on Rails: creates dynamic Web pages with interface looking like application Python scripting language
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  • Dynamic Content (contd.) The future of dynamic Web page generation Criticisms of previous approaches Do not solve problem of dynamic page generation Shift dynamic page creation from HTML coders to ASP (JSP, PHP) programmers Apache Cocoon project initiative Query XML formatted data and generate output in multiple formats HTML output: useful for dynamic Web page creation May apply style sheet to data: tailored response Portable Document Format (PDF) file, Wireless Markup Language (WML) file E-Business, Eighth Edition12
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  • E-Business, Eighth Edition13 Dynamic Content (contd.) The future of dynamic Web page generation (contd.) Latest Cocoon version Divides work into four areas of concern Limits area interactions to five specific contracts Breaks direct connection between logic and style Future dynamic Web page design easier Other initiatives Microsoft: Microsoft.NET Framework Oracle: including explicit PHP support (other scripting languages) in its database products
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  • E-Business, Eighth Edition15 Various Meanings of Server Server Any computer providing files (programs) to other computers Connected through network Server software Server computer software Makes files (programs) available to other computers Sometimes included with operating system Servers connect through router to the Internet Run Web server software
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  • E-Business, Eighth Edition16 Various Meanings of Server (contd.) Web servers Computers connected to the Internet Run Web server software Makes servers files available to other computers E-mail server: handles incoming, outgoing e-mail Database server Runs database management software Server describes several types of computer hardware, software Note context
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  • Web Client/Server Communication Web browser requests files from Web server Transportation medium: the Internet Request formatted by browser using HTTP Request sent to server computer Server receives request Retrieves file containing requested Web page Formats using HTTP Sends back to client over the Internet Client Web browser Browser displays information if it is an HTML page Graphics can be slow to appear E-Business, Eighth Edition17
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  • E-Business, Eighth Edition18 Two-Tier Client/Server Architecture Two-tier client/server architecture Messages created and read Only by client and server computers Request message: client requesting file from server Request line: contains command, target resource name, protocol name, version number Optional Request headers: file type information that client will accept Entity body: passes bulk information to server
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  • Two-Tier Client/Server Architecture (contd.) Server receives request message Executes command included in message Retrieves file from disk Creates response message: sent back to client Identical structure as request message (slightly different function) Response header line: server HTTP version, response status, status information explanation Response header field: information describing servers attributes Entity body: returns HTML page requested by client (optional) E-Business, Eighth Edition19
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  • E-Business, Eighth Edition21 Three-Tier and N-Tier Client/Server Architectures Three-tier architecture Extends two-tier architecture Allows additional processing before server responds to clients request n-tier architectures Higher-order architectures; more than three tiers Third tier supplies information to Web server Databases and related software application
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  • Three-Tier and N-Tier Client/Server Architectures (contd.) Four, five (or more) tiers include: Software applications (like three-tier systems) Databases, database management programs Work with software applications, generate information turned into Web pages, send to requesting client Example: catalog-style Web site Search, update, display functions Track customer purchases stored in shopping carts, look up sales tax rates, keep track of customer preferences, query inventory databases, keep company catalog current E-Business, Eighth Edition22
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  • E-Business, Eighth Edition24 Software for Web Servers Web server software May run on: One or several computer operating systems Types of Web server software/programs Operating system software Web server software itself Other programs Internet utilities E-mail software
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  • Operating Systems for Web Servers Operating system tasks Running programs, allocating computer resources, providing input and output services More responsibilities (large systems) Tracking multiple users, ensuring no interference Microsoft Windows Server products Considered simple to learn and use Raise security concerns Linux-, UNIX-based products Popular Considered secure as Web servers E-Business, Eighth Edition25
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  • E-Business, Eighth Edition26 Operating Systems for Web Servers (contd.) Linux (open-source operating system) Fast, efficient, installs easily Open-source software Developed by community of programmers Software available for download (free) Others use it, improve it, submit improved versions More information Open Source Initiative Web site
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  • E-Business, Eighth Edition27 Operating Systems for Web Servers (contd.) Companies selling Web server computers Include Linux in default configurations Companies may buy Linux through commercial distributors Include useful additional software (installation utilities) Pro