Intro to internet 1
- 1. Internet
- 3. INTERNET???? • It is the largest network in the world that connects hundreds of thousands of individual networks all over the world. • The popular term for the Internet is the “information highway”. • Rather than moving through geographical space, it moves your ideas and information through cyberspace – the space of electronic movement of ideas and information.
- 4. • No one owns it • It has no formal management organization. • As it was originally developed by the Department of defense, this lack of centralization made it less vulnerable to wartime or terrorist attacks. • To access the Internet, an existing network need to pay a small registration fee and agree to certain standards based on the TCP/IP (Transmission Control Protocol/Internet Protocol) . • A global network connecting millions of computers
- 5. What is Web? • The Web (World Wide Web) consists of information organized into Web pages containing text and graphic images. • It contains hypertext links, or highlighted keywords and images that lead to related information. • A collection of linked Web pages that has a common theme or focus is called a Web site. • The main page that all of the pages on a particular Web site are organized around and link back to is called the site’s home page.
- 6. • Body (BAN) • Personal (PAN) • Near-me (NAN) • Storage (SAN) • Local (LAN) • Home (HAN) • Campus (CAN) • Metropolitan (MAN) • Wide (WAN) • Global (GAN) • Interplanetary Internet Types of internet:-
- 7. • J.C.R, Licklider of MIT – first proposed a global network of computers in 1962. • Leonard Kleinrock of MIT & later UCLA developed theory of packet switching (basic internet connections) • Ray Tomlinson – e-mail HISTORY OF INTERNET
- 8. The Internet exploded into the public consciousness in the mid 1990s Approximately the Internet grew from 72 million in 2000 to 162 million in 2002 E-commerce is growing rapidly. Tim Berners-Lee is arguably the pivotal figure in the surging popularity of the Internet THE INTERNET AS PHENOMENON
- 9. GETTING START The Internet Service Provider and the Browser An internet user needs • a computer • a modem (dial-up, cable or DSL) • a network connection • the related software • an Internet Service Provider (ISP) • Browser An ISP provides the server computer and software to connect to the Internet
- 10. • A browser is software used to explore the Internet • Microsoft Internet Explorer (IE) • Others like Netscape, Opera Google crome and Mozilla are available.
- 11. Uniform Resource Locators • The IP address and the domain name each identify a particular computer on the Internet. • However, they do not indicate where a Web page’s HTML document resides on that computer. • To identify a Web pages exact location, Web browsers rely on Uniform Resource Locator (URL). • URL is a four-part addressing scheme that tells the Web browser: What transfer protocol to use for transporting the file The domain name of the computer on which the file resides The pathname of the folder or directory on the computer on which the file resides The name of the file
- 12. Structure of a Uniform Resource Locators http://www.chicagosymphony.org/civicconcerts/index.htm protocol Domain name pathname filename http => Hypertext Transfer Protocol
- 13. communicating by using links – the clickable text or image that transport a user to the desired web site Domain name - the address of the site’s host computer. - “com” called top-level domain and represents the purpose of organization or entity. “com” – commercial “edu” – education “gov” – government “org” – organization “net” - networking center HTTP(Hypertext Transfer Protocol)
- 14. Hypertext Markup Language (HTML) • HTML uses codes, or tags, to tell the Web browser software how to display the text contained in the document. • For example, a Web browser reading the following line of text: <B> A Review of the Book<I>Wind Instruments of the 18th Century</I></B> • recognizes the <B> and </B> tags as instructions to display the entire line of text in bold and the <I> and </I> tags as instructions to display the text enclosed by those tags in italics. • The standard used on the web is Hypertext markup language (HTML).
- 15. Search Engine • A search engine is software, usually located at its own web site, that lets a user specify search terms; the search engine then finds sites that fit those terms • A browser usually offers links to one or more search engines, or a user can simply link to the site of a favorite search engine • Example : a. Yahoo b. Altavista c. About d. AllTheWeb e. Google f. Lycos
- 16. A selection of Internet Search Tools Directories About Human experts, called guides compile directories organized around specific topics Yahoo! Well-organized categories let the user switch from browsing to searching in a certain area; but finds only keywords, not any word on a site. AlltheWeb Fast; supports a large number of languages; can limit result to specific domains. AltaVista Very fast; indexes every word on every page of every site; searches Usenet too; excellent for custom searches.
- 17. Google Result raked by algorithm based on number of links from other pages. HotBot Fast; unique search options let you restrict searches; very comprehensive; excels at finding current news Lycos Numerous search options, a comprehensive directory, and good returns on simple searches.
- 18. NON-WEB SERVICES OF THE INTERNET 1. Newsgroups 2. File Transfer Protocol (FTP) 3. Telnet 4. E-mail
- 19. 1. Newsgroups • Usenet – an informal network of computers Allows posting and reading of messages Typically focuses on specific topics Requires a newsreader • Some are moderated – Messages sent to a moderator, who determines whether the message is appropriate – Prevents users from attacking other members and prevents inappropriate material from being posted
- 20. 2. File Transfer Protocol (FTP) • A protocol for transferring files among computers. • FTP servers maintain collections of downloadable files –Downloading can often be done anonymously, without logging in • Many FTP servers can be accessed through Web browser
- 21. 3. Telnet • A protocol that allows remote users to log onto a host computer. Users use their own PCs Users log in over the Internet Users’ experience is the same as if they were sitting at the host computer’s local terminal • Remote user typically has to have a user ID and password
- 22. 4. E-mail • The most commonly used feature of the Internet • Network provides mail server : – Collects and stores messages in mailbox – E-mail address consists of user name, followed by @ symbol, then domain name of mail server • E-mail client software on your computer – Allows you to manage your e-mail messages – Features • Address books • The ability to attach files • Filters – Direct incoming e-mail to specific folders – Block spam