1. 1 Internet History Internet made up of thousands of networks worldwide No one in charge of Internet - No governing body Internet backbone owned by private companies

2. 2 Looking at the Net Taken from: http://www.cio.com/WebMaster/sem2_net.html

3. 3 Understanding the Map Computers use TCP/IP to communicate (Transmission Control Protocol/Internet Protocol) Computers use client/server architecture

4. 4 Internet Providers: Research and Educational Institutions Government and Military Entities Businesses Private Organizations Commercial Providers

5. 5 Internet Protocols Email (Simple Mail Transport Protocol) Telnet (Login to remote host computer) FTP (File Transfer Protocol) - transfers files between server and client HTTP (HyperText Transfer Protocol)

6. 6 History WWW or Web or W3 includes all information, text, images, audio, video, and computational services that are accessible from the internet July 8, 1999 Nature - approximately 800 million pages of publicly accessible information (1) Web continues to grow, tripling in size over the past two years (2) (1) Steve Lawrence & C. Lee Giles, “Accessibility of Information on the Web,” Nature 400 (July 8, 1999), 107 (2) OCLC Office of Research, “June 1999 Web Statistics” Web Characterization Project

7. 7 WWW System of Internet servers that support hypertext to access several Internet protocols on a single interface Almost all protocols accessible on Internet are accessible on web (email - FTP - Telnet - etc) In addition, WWW own protocol: HyperText Transfer Protocol

8. 8 HTTP Hypertext - means of information retreival Contains links that connect to other documents Links selected by user Virtual “web” of connections

9. 9 HTTP (cont) Produce HTTP through HTML HyperText Markup Language Way of writing or creating with “tags” added to tell information –i.e. Bold yields Bold

10. 10 More History Internet initially conceived in 1989 by Tim Berners-Lee at CERN (European Particle Physics Lab in Switzerland) Needed a wide variety of information to be shared and distributed to many different computers and platforms “Universal readership”

11. 11 Web Popular Because: Easy to use Easy to navigate Combines words, graphics, sound, video Easy to Publish Plethora of information Reach larger audience

12. 12 Summary: Web vs. Internet What is the relationship between the web and the Internet? The Internet contains physical components –computers –networks –services

13. 13 Web vs. Internet The Internet connects thousands of computers across the world, but it is the web that allows communication to occur Web - abstraction and common set of services on top of the Internet Web - set of protocols and tools that let us share information with each other

14. 14 Browsers What is web browser? browser: a program used to view HTML documents A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web The first web browser was invented in 1990 by Sir Tim Berners-Lee. It was called WorldWideWeb (no spaces) and was later renamed Nexus. Netscape Navigator (Communicator) –Product of Netscape (Now owned by AOL) –Originally was dominant –Multi-platform (all operating systems) Internet Explorer –Product of Microsoft –Current Dominant Browser –Not available for all operating systems Browser compatibility problems can cause web page problems

15. 15 Browsers What is web browser? browser: a program used to view HTML documents A web browser is a software application for retrieving, presenting, and traversing information resources on the World Wide Web The first web browser was invented in 1990 by Sir Tim Berners-Lee. It was called WorldWideWeb (no spaces) and was later renamed Nexus. What is website? web site: a computer connected to the internet that maintains a series of web pages on the World Wide Web; A website, is a set of related web pages containing content such as text, images, video, audio, etc. A website is hosted on at least one web server, accessible via a network such as the Internet or a private local area network through an Internet address known as a Uniform Resource Locator. All publicly accessible websites collectively constitute the World Wide Web.

16. Web Page A webpage is a document, typically written in plain text interspersed with formatting instructions of Hypertext Markup Language (HTML, XHTML). A webpage may incorporate elements from other websites with suitable markup anchors. Web pages are accessed and transported with the Hypertext Transfer Protocol (HTTP), which may optionally employ encryption (HTTP Secure, HTTPS) to provide security and privacy for the user of the webpage content. The user's application, often a web browser, renders the page content according to its HTML markup instructions onto a display terminal 16

17. The first web browser was invented in 1990 by Sir Tim Berners-Lee. It was called WorldWideWeb (no spaces) and was later renamed Nexus. In 1993, browser software was further innovated by Marc Andreessen with the release of Mosaic (later Netscape), "the world's first popular browser", [5] which made the World Wide Web system easy to use and more accessible to the average person. Andreesen's browser sparked the internet boom of the 1990s. [5] The introduction of Mosaic in 1993 – one of the first graphical web browsers – led to an explosion in web use. Andreessen, the leader of the Mosaic team at NCSA, soon started his own company, named Netscape, and released the Mosaic- influenced Netscape Navigator in 1994, which quickly became the world's most popular browser, accounting for 90% of all web use at its peak (see usage share of web browsers). [5] 17

18. 18 Two Basic Approaches to Searching (although not really “basic”) Search Engines Subject Directories

19. 19 What are Search Engines? Designed to assist you in searching through the enormous amount of information on the Web No single search tool has everything Each engine is a large database which utilizes different search techniques and tools (spiders or robots) to build indexes to the Internet (some also utilize submissions and administration)

20. 20 Which Search Engine? Yahoo Altavista Excite Google NorthernLights Hotbot Infoseek See Handout - “The Little Search Engine that Could”