The Internet and the World Wide Web CIT 230 Web Design
History of the Internet Began as ARPANET in 1950 s Funded by the Department of Defense Purpose was to share resources among DOD contractors and encourage research in computer networking Many academic institutions signed on Continued to grow but limited to academic and military uses, not for general public. 1989 Internet begins to evolve into a common medium with the advent of the Hypertext Transfer Protocol and the birth of the World Wide Wait, er Web!
1989 - World Wide Web Tim Berners-Lee and CERN Wanted a standardized way in which scientists could communicate with each other Codified HTML, based on SGML Hyperlinking used. Web metaphor emphasizes the intricate interconnectedness of the WWW Milestone: 1993-National Center for Supercomputing Applications (NCSA) develops Mosaic. Marc Andreesen at U of Illinois. Later Mosaic becomes Netscape
What is the Internet? Collection of computer networks Meta-network (a network of networks) Uses a fixed set of protocols
Backbones Transportation analogy sidewalks, streets, boulevards, highways and interstates Backbone is the internet equivalent of the interstate. NAPs: Network Access Points connect the backbone to regional networks San Francisco, San Jose, Chicago, New York, and Washington, D.C. are major backbone access points in the U.S.
Protocols
Internet Protocols (TCP/IP) Universal Translator of Networking Auto recovery and rerouting built in to the protocol in case of damaged node (Nuclear attack) Check/recheck protocol Packet switched breaking down large chunks of data into smaller ones called packets IP moves these packets from node to node. Delivery is based on unique IP numbers or addresses At delivery, TCP verifies that all the info is intact and reassembles it
Internet Protocols (TCP/IP) Transmission Control Protocol / (over) Internet Protocol Developed for military so hardware communication could occur regardless of manufacturer
Hypertext Transfer Protocol Hypertext Transfer Protocol HTTP:// Protocol used to send information (text, graphics, audio, video) across the World Wide Web HTTP request sent from users browser to the HTTP server and the response is the web page displayed in the browser Hypertext Links that make the web interconnected
Extensible Hypertext Markup XHTML Language a set of codes or commands that control how text and images will appear when it is transferred to a users browser from the server Uses tags open and close tags <h1></h1> to mark up the text for formatting <h1>this is a Heading</h1>
Web Browsers Program that sends requests to the HTTP server Displays the server s response Examples Netscape Navigator Internet Explorer Browser Types Graphical-text, sound, images-still and moving Tend to be slower Ability to bookmark sites visited Non-graphical, text only browsers Early development, ASCII text only, Very fast
Web Addresses Uniform Resource Locator (URL) textual address of the data storehouse Each part of the URL has a meaning http://www.byui.edu/academics/index.htm http:// -indicates the protocol to be used www -identifies the web server byui identifies the location or company edu identifies the location s domain type /academics identifies a subdirectory on the server index.htm identifies the specific page being requested.
Domain Name System The text version of the IP address Each domain name has a unique IP address associated with it IP Address URI 157.201.10.1 www.byui.edu 136.1.240.21 www.ford.com
Top Level Domains An indication of the kind of domain.edu-educational.gov-government.com-commercial.mil-military.net-networking.org-nonprofit organization Seven new top level domains proposed to be added in November of 2000.aero-air-transport.biz-business.coop-cooperatives.info-multi purpose.museum-museums.name-individuals.pro-professions
Top Level Domains/2nd Level Domains In 2001-.biz,.info and.name were made operational Second Level Domain The part of the address that actually identifies the organization.byui in the previous example
Search Engines and Web Directories The card catalogues of the Internet Search services offer subject guides to aid in a search Yahoo! Is really a service with catalogued entries Search engines-lycos, Alta Vista, Info-seek, Google Meta-tags used to assist in the search Automated-more like a database search. Often more current and able to report more minute details of information that may be useful
Search Techniques AND OR docs containing both words docs with either or both words NOT omit specified words Boolean logic Can use + and signs as well
FTP File Transfer Protocol Prior to the web, the way to transfer files over the internet Usually UNIX system odd commands like get and put Telenet allows users to log on to remote systems and search directories for files and search databases for information
Usenet Electronic newspaper Articles posted to a news server Read by anyone with a newsreader software that allows access to a news group Newsgroups are interactive readers can respond to articles by posting their own articles Forms a discussion thread Netiquette rules are enforced
ISPs Internet Service Provider company that allows subscribers to connect to the internet Phone, cable, satellites Basic services: email, simple web hosting ISP selection local access to avoid long distance charges Reliability-little down time and 24 hour access Cost varies-shop around Connection speed