1. CSCI-235 Micro-Computers in Science The Internet and World Wide Web

2. The Internet and World Wide Web: Welcome to Cyberspace2 The Internet  A network of networks  Began in 1969 as ARPAnet (Advanced Research Projects Agency)  No central authority and thus impossible to state the precise size

3. The Internet and World Wide Web: Welcome to Cyberspace3 The Internet and Web: What’s the Difference?  The Internet is the physical connection of millions of networks  The Web uses the Internet for its existence  The Web consists of hypertext embedded on Web pages that are hosted on Web sites Began in 1991 at the European Particle Physics Laboratory (CERN) in Switzerland

4. The Internet and World Wide Web: Welcome to Cyberspace4 Web Browsers and Servers  Web browsers display a Web document and enable users to link to other Web pages The first browsers were text-only Mosaic was the first graphical browser  Web servers respond to the requests of browsers. They find and send requested resources back to the browser

5. The Internet and World Wide Web: Welcome to Cyberspace5  Menu Bar File Edit View Favorites Tools Help  Address Bar URL  Toolbar Back Button Forward Button Stop Refresh Home Search Favorites History Microsoft Internet Explorer

6. The Internet and World Wide Web: Welcome to Cyberspace6 Status Bar Menu Bar Tool Bar Address Bar Hyperlink

7. The Internet and World Wide Web: Welcome to Cyberspace7  Web addresses are an addressing system that identifies where a Web resource is located  The uniform resource locator (URL) is the standard used to identify Web resources  The URL consists of: URL Uniform Resource Locator (URL) http:// Protocol identifies the means of access www.yahoo.com/ Server contains the domain name of the Web server help/shop/ Path identifies the location of the document shop-01.html Resource specifies the filename of the resource

8. The Internet and World Wide Web: Welcome to Cyberspace8 Search Engines  A program that systematically searches the Web for documents on a specific topic  Uses a key word or words as a query  Several search engines are available  Each search engine has its own database  No search engine is best  Uses Boolean (logical) operators  Returns “hits” or documents once search has been submitted

9. The Internet and World Wide Web: Welcome to Cyberspace9 Search Rules and Techniques  Specify Boolean operators AND -- Includes all findings of both key words OR -- Looks for only one of the specified key words NOT -- Allows you to exclude certain key words  Use multiple search engines  Read online help about search criteria used for a particular search engine

10. The Internet and World Wide Web: Welcome to Cyberspace10 http://www.altavista.com/http://www.msn.com/ http://www.go.com/http://www.excite.com/ http://www.lycos.comhttp://www.askjeeves.com/ http://www.webcrawler.com/http://www.google.com/ http://www.yahoo.comhttp://www.search.com/ Popular Web Search Engines

11. The Internet and World Wide Web: Welcome to Cyberspace11 Security and Privacy  Secure transactions Https protocol Encryption  Privacy A cookie is a small file written to your disk each time you visit a site

12. The Internet and World Wide Web: Welcome to Cyberspace12 HTML  HTML – HyperText Markup Language: language for all Web documents  HTML Codes - Necessary to format the page