Introduction to Information Technology ch 02_a
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Introduction to Information Technology ch 02_a
- 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. 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. 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. 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
- 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. 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
- 9. The Internet’s History • 1990s –ARPANET shut down in 1990 –NSFNet funding was disconnected in 1995 –Commercial networks take over 2A-9
- 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
- 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. 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. 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. Understanding the World Wide Web 2A-15
- 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. 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. 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. 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. 2A-20
- 21. • Wed document in URL 2A-21 WedWed DocumentDocument
- 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
- 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. 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. Searching the Web • Types of search engines: – Directories-based • Categorize the documents into subjects i.e. educationschoolsubjectcomputer • Example: – www.looksmart.com/ – Keyword based • Find sites by keyword – www.google.com 2A-26
- 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 • www.microsoft.com, www.cnn.com – Advanced search: uses form having filters • www.google.com, www.yahoo.com 2A-27
- 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.
- 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 – www.google.com – www.yahoo.com • See next slide
- 31. 2A-31
- 32. Search Techniques • Logical operators: AND, OR, NOT 2A-32
- 33. 2A-33
- 34. Copyright © 2006 by The McGraw-Hill Companies, Inc. All rights reserved.McGraw-Hill Technology Education Chapter 2A End of Chapter
Notes de l'éditeur
- Discussion point Have students discuss the pros and cons of no central control for the Internet. Some discussion points can include copyright issues, free speech, advertisements and information access to all.
- Teaching point Direct the students to several different streaming video sites. Www.launch.com and www.apple.com/QuickTime are two excellent examples. Be sure your classroom browsers have the appropriate plug-ins.
- Insider information The search engine www.google.com has become one of the hottest search engines on the planet. It is so popular, it’s name has become a verb. For example, “I googled the answer last night” is a phrase uttered on college campuses the world over.