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Introduction to Information Technology ch 02_a


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B.S Ist semester

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Introduction to Information Technology ch 02_a

  1. 1. Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill Technology Education McGraw-Hill Technology Education Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.
  2. 2. Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill Technology Education Chapter 2A The Internet and the World Wide Web
  3. 3. 2A-3 The Internet’s History • 1965- ARPA project – ARPA of the US department of defense started a project in 1965 – Purpose was to connected universities and defense bases with each other
  4. 4. The Internet’s History • 1969 ARPANET – The network established in 1969 and was named ARPANET – Initially was consisting of only four (04) host computers • ARPANET 1973 – Extended to the whole Europe 2A-4
  5. 5. 2A-5 ARPANET 1973
  6. 6. 2A-6 The Internet’s History • 1980-National Science Foundation (NSF) – Joined the project in 1980 when Department of Defense stopped funding • Mid-1980s – NSFNet – Network between 5 supercomputers centers for academic and research purpose – Initially they used ARPANET for connection but the existing ARPANET was unable to handle that much load and thus they started their own network NSFNet – No commercial traffic allowed by NSFNet
  7. 7. The Internet’s History • Internet – The link between ARPANET, NSFNet and other networks was called Internet – Definition: • The global network of networks is called Internet • Internetworking – The process of connecting different networks 2A-7
  8. 8. The Internet’s History 2A-8
  9. 9. The Internet’s History • 1990s –ARPANET shut down in 1990 –NSFNet funding was disconnected in 1995 –Commercial networks take over 2A-9
  10. 10. 2A-10 Today and the Future • 100,000 new web sites per month • More than 50% of U.S. households online • Access is available throughout the U.S. • Eventually access will be global
  11. 11. 2A-11 U.S. Internet Growth
  12. 12. The Internet’s Major Services • The World Wide Web (WWW) • Next chapter – Electronic mail (e-mail) – News – File Transfer Protocol (FTP) – Chat – Instant messaging – Online services – Peer-to-peer services 2A-12
  13. 13. 2A-13 Understanding the World Wide Web • World Wide Web – Also called Web or WWW • Started in1989- – At European Particle Physics Laboratory in Geneva, Switzerland • Purpose – To create a simple way to access any document that are stored on a network
  14. 14. Understanding the World Wide Web • 1993 -Tim-Berners Lee – In 1993 Tim-Berners Lee gave the idea to linked documents stored on different computers across the world (on different networks) or on different computers on a network 2A-14
  15. 15. Understanding the World Wide Web 2A-15
  16. 16. How the web works • The working of web need: – Hypertext document • Collection of text files, pictures, sounds, movies – HTML language • A markup language used to create hypertext documents (called Web Page) • These documents are linked through hypertext links (also called hyperlinks) • Web site are formed – A collection of interrelated web pages is called Web Site – Hypertext transfer protocol (HTTP) • To support web pages 2A-16
  17. 17. How the web works • Publishing a web page – Uploading a wed page on server is called publishing a page – Also called posting a page 2A-17
  18. 18. Web Browsers • A software application design to find a hypertext document (Web page) and then open the Web page on the user computer • Examples: – Internet Explorer – Mozilla Firefox – Google Chrome – etc. 2A-18
  19. 19. Uniform Resource Locator (URL) • An Internet address of a web page is called URL – Format: • Type:addresspath – Type: specify type of the server: web server or file server – Address: address of the server – Path: location within the file structure of the server 2A-19
  20. 20. 2A-20
  21. 21. • Wed document in URL 2A-21 WedWed DocumentDocument
  22. 22. 2A-22 Understanding The Internet • Helper applications and multimedia contents – Limitation of web-browsers: • Browsers individually cannot display every type of contents (video, audio, animations) – Solutions to the problem • Plug-ins are the special application softwares that are used to play the contents in real. • Enhance a browser’s functionality • Used for Streaming audio and video • Sends the file in small chunks • Chunks downloaded while others play
  23. 23. 2A-23 Streaming Audio
  24. 24. 2A-24 Using a Browser And The WWW • Start the browser • Enter the URL – Three methods are used for entering URL • The home page of the web site will load in browser window • Use hyperlinks to navigate through the website • When finished, close the browser
  25. 25. 2A-25 Searching the Web • The Web is unorganized collection of billions of documents from different sources • It is too difficult to get honest, trusty and accurate information from the web easily • To solve this problem: – Search engines: are used
  26. 26. Searching the Web • Types of search engines: – Directories-based • Categorize the documents into subjects i.e. educationschoolsubjectcomputer • Example: – – Keyword based • Find sites by keyword – 2A-26
  27. 27. Searching the Web • Problems in search engines – Sponsored links • The links (web sites) for which the owner pays to the search engines owners for displaying their links at the top of the links in the search engines windows – Irrelevant documents are retrieved • Solutions to the problems – Website-specific searching tool •, – Advanced search: uses form having filters •, 2A-27
  28. 28. 2A-28 Searching the Web • Metasearch sites – A metasearch engine is a search tool that sends user requests to several other search engines and/or databases and aggregates the results into a single list or displays them according to their source.
  29. 29. • 2A-29
  30. 30. 2A-30 Search Techniques • Quote the exact phrase • Boolean operators in search • Use the keyword NEAR • Avoid common words – Is, or, no etc. • Use the site’s advanced tools – – • See next slide
  31. 31. 2A-31
  32. 32. Search Techniques • Logical operators: AND, OR, NOT 2A-32
  33. 33. 2A-33
  34. 34. Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill Technology Education Chapter 2A End of Chapter