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CSCI 1101 Intro to Computers 7. Introduction to the Internet ACS 160 - Chapter 8 - The Internet What is cyberspace? The term Cyberspace, a computer-generated world that exists in a hazy realm between reality and imagination, was coined in 1984 by science fiction writer William Gibson. 2 ACS 160 - Chapter 8 - The Internet What is the "Internet" The Internet, which has been evolving for over the past 30 years, is a collection of local, regional, national, and international computer networks linked together to exchange data and distribute processing tasks. 3 ACS 160 - Chapter 8 - The Internet Brief history of the Internet The United States created ARPA (Advanced Research Projects Agency). to help scientists communicate and share valuable computer resources in response to the Soviet Union’s launch of Sputnik in 1957, the first artificial satellite 4 The ARPANET, created in 1969, connected computers at four universities. ACS 160 - Chapter 8 - The Internet Continuing definitions of Internet Connecting two or more networks creates an “internetwork” or “internet.” The Internet is huge and continues to grow. size can only be estimated Internet host - a computer on the Internet that provides services data routing e-mail Web pages 5 ACS 160 - Chapter 8 - The Internet Size of the Internet's data Internet traffic - the number of bytes transmitted from one Internet host computer to another exceed 6 100 terabytes per week in 1997 Michael Dertouzos, director of the MIT Laboratory of Computer Science, estimates that the world has 1 exabyte to store data. Exabyte - 1 quintillion bytes. ACS 160 - Chapter 8 - The Internet How the Internet works A network service provider (NSP) maintains a series of communications links for Internet data. links connect at network access points (NAPs) major Internet links are called the Internet backbone 7 TCP/IP (Transport Control Protocol/Internet Protocol) - computer rules used by every computer that connects to the Internet ACS 160 - Chapter 8 - The Internet How to gain access to the Internet You connect to the Internet by connecting to an Internet Service Provider (ISP) which connects to the Internet backbone. ISP - company that maintains an Internet host computer 8 provides Internet access to businesses and individuals charges monthly fee offered over telephone lines, cable TV, or satellite dish Dial-up connection - a connection that uses a phone line to establish a temporary Internet connection ACS 160 - Chapter 8 - The Internet Internet addresses Every computer that connects to the Internet has a unique number called an IP address. A router examines the IP address and then forwards the data to its destination. Many host computers have an easy-to-remember name which is officially called a fully qualified domain name. most people call it a domain name Domain name 9 set of four numbers between 0 and 255 separated by periods typed in lowercase ends with three letter extension which is its top-level domain ACS 160 - Chapter 8 - The Internet What is a web-site really? 10 A computer with a domain name is referred to as a site. Web site - location in a computer somewhere on the Internet. Original Internet Top-level domains ACS 160 - Chapter 8 - The Internet How are Web-sites and Web-pages different? Web sites are composed of a series of Web pages. URL (Uniform Resource Locator) - an Internet address of a document on a computer 11 each page stored as a file referred to by a unique URL begin with http:// HTTP stands for Hypertext Transfer Protocol - the protocol that allows Web browsers to communicate with Web servers. ACS 160 - Chapter 8 - The Internet How do pages get "on" the Internet? Web server - computer with special software for transmitting Web pages over the Internet Most 12 domain names prefixed with www Home page - identifies the site and typically contains links to other pages at the site ACS 160 - Chapter 8 - The Internet Is the Web and the Internet one and the same? The Web is only one of the Internet’s many services. The Internet also provides e-mail file transfers discussion groups real-time chat 13 ACS 160 - Chapter 8 - The Internet Other Internet services 14 The Internet also includes FTP servers which maintain files that you can transfer to your own computer. Usenet servers and IRC servers handle exchange of comments among members in chat groups. ACS 160 - Chapter 8 - The Internet What is the role of Web browsers? Web browsers provide Internet users with allpurpose client software for accessing many types of servers. 15 ACS 160 - Chapter 8 - The Internet Origin of the Web The World Wide Web, or “the Web” was created in 1990 at the European Laboratory for Particle Physics. The Web Internet service that stores and provides information easy to use source of graphical information consists of documents (Web pages) that contain information on a particular topic 16 ACS 160 - Chapter 8 - The Internet How web-pages provide linkage A Web page may contain links that point to other Web pages. makes it easy to follow a thread of related information 17 You request a Web page from a Web browser by typing in a URL or clicking a Web page link. The page that displays when your browser first starts is called the home page ACS 160 - Chapter 8 - The Internet What is a Web Portal? A Web portal is a Web site that provides a group of popular Web services. search engines e-mail accounts chat rooms links to shopping, weather, news, and sports 18 ACS 160 - Chapter 8 - The Internet Some current web portals Popular Web portals include America Online, GO Network, Lycos, and Yahoo Some portals are maintained by commercial information services. also serve as ISPs charge monthly membership fee 19 ACS 160 - Chapter 8 - The Internet Content of a Web Page Web pages now include multimedia elements such as sound, animation, and video. stored 20 in a file Streaming media - computer plays a media file while receiving it In-place multimedia technology - plays a media element as a seamless part of a Web page ACS 160 - Chapter 8 - The Internet Simple animated Gifs This animated gif plays in place as part of the Web page. 21 ACS 160 - Chapter 8 - The Internet More robust multi-media techniques Multimedia overlay technology adds a separate window to your screen for multimedia elements. Multimedia overlay technology 22 ACS 160 - Chapter 8 - The Internet Browser add-ons A software module that provides your computer with the capability to view or play a specific type of file is called a player, plug-in, or viewer. The Web browser maintains list of media players installed on your computer. most browsers provide a link to a site where you can download a necessary player 23 ACS 160 - Chapter 8 - The Internet Download vs. Upload Downloading is the process of transferring a file from a remote computer to your computer. 1. Right-click the picture you want to copy. 2. Choose Save Picture as 24 ACS 160 - Chapter 8 - The Internet Download vs. Upload (cont.) 25 Uploading - the process of sending a copy of a file from your computer to a remote computer You can upload files using FTP client software, such as WinFTP. ACS 160 - Chapter 8 - The Internet How to download software The Internet is a good source of free software. Most downloadable software is stored as a self-extracting file, a single file that holds all of the modules for the software. download software 26 sites include instructions for downloading ACS 160 - Chapter 8 - The Internet Example of software available on the Web You can take advantage of thousands of shareware, freeware, and trial versions of software. 27 ACS 160 - Chapter 8 - The Internet Other Internet activities In addition to e-mail, people can interact on the Internet by joining a discussion group. 28 takes place asynchronously, meaning discussion participants are not online at the same time A chat group is a discussion group which takes place synchronously (participants are online at the same time). Multi-player gaming - gives you an opportunity to play with or against, other players all over the Internet ACS 160 - Chapter 8 - The Internet HTML Authoring tools In addition to using HTML, Web authoring tools make it much easier to create Web pages. use word processor-style interfaces wizards predesigned templates Popular Web authoring software includes Microsoft FrontPage and Claris Home Page. contain 29 tools for managing Web sites ACS 160 - Chapter 8 - The Internet Web page guidelines Plan your Web page so that it fulfills its purpose. Design a template to unify your pages. Follow basic rules for good Web page design: 30 narrow line widths proofread use contrasting colors; do not use drab colors do not use overly large graphic files use graphics with .jpg or .gif filename extensions use thumbnails to link to larger version of large graphics ACS 160 - Chapter 8 - The Internet More web page guidelines 31 Identify your pages. Include dates. Include navigational elements. Respect the copyright and intellectual property rights of other Web sites. ACS 160 - Chapter 8 - The Internet How do businesses use the web? E-commerce refers to buying products and services by means of the Internet. 32 online shopping online auction sites Like big businesses, individuals can also set up their own e-commerce site. Many Web hosting services and portal sites offer an e-commerce enabled Web site, which simplifies the process of constructing an online storefront. ACS 160 - Chapter 8 - The Internet The role of an ISP An Internet Service Provider (ISP) connects you to the Internet by providing you with a user account on a host computer that has access to the Internet. Internet connections are also available through commercial information services, such as AT&T WorldNet and America Online, and some cable TV companies. charge 33 $10 - $40 per month ACS 160 - Chapter 8 - The Internet Physical connections Most people use a telephone line to access the Internet. can also use cable, cellular phone, or personal satellite dish 34 You need a computer, modem, and telephone line. ACS 160 - Chapter 8 - The Internet Connection speeds 35 Connection speed is the maximum speed that your modem can communicate with the ISP’s modem. Transfer rate is the speed at which you can send or receive data.