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Introduction to Internet
The Internet is a worldwide collection of interconnected computer networks that enables businesses, organizations, governments, and individuals to communicate in a variety of ways. One of the most popular ways users communicate on the Internet is by publishing and interacting with Web pages. You can also use the Internet to send and receive e-mail, chat with other users, and transfer files between
computers.
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| Internet Explorer |
Types of Connections
Users connect to the Internet through a variety of methods. A relatively inexpensive but slow way to connect is with dialup service, which involves using a modem and a phone line. Faster ways to connect include DSL (digital subscriber line), cable modem, satellite, and ISDN (integrated services digital network). Networks include special wireless transmitters that allow computers to access the Internet wirelessly. Companies that help you connect to the Internet are known as Internet service providers, or ISPs.
Connection Speeds
Connection speeds play an important part in a user’s Internet experience because slower connections result in slower file transfers and Web page viewing. Dialup connections offer the slowest access to the Internet at up to 56 kilobits per second, or Kbps, followed by ISDN connections at 64 to 128 Kbps. DSL usually offers connection speeds of up to 3 megabits per second, or Mbps, while cable modems can achieve speeds of up to 6 Mbps. A Web page that takes about 20 seconds to download via dialup can take less than a second using a cable modem.
Communication Standards
The Internet infrastructure relies on a variety of protocols that dictate how computers and networks talk to each other. For example, Transmission Control Protocol/Internet Protocol, or TCP/IP, is a set of rules that control how Internet messages flow between computers. Hyper Text Transfer Protocol, or HTTP, is a set of rules that determine how browsers should request Web pages and how server computers should deliver them. Having agreed-upon protocols allows seamless communication among the many different types of computers that connect to the Internet.
The World Wide Web
The World Wide Web is a giant collection of documents, or pages, stored on computers around the globe. Commonly called the Web, this collection of pages represents a wealth of text, images, audio, and video available to anyone with a computer and an Internet connection. Web pages are stored on servers, which are Internet-connected computers running software that allows them to serve up information to other computers. When you place a text file, image, or other document in a special Web directory on a server, that information is available for other Web users to view.
URLs and Links
Every page on the Web has a unique address called a URL, which is short for Uniform Resource Locator. A URL looks like this: http://www.example.com/index.html. If you know a page’s URL, you can type it into a Web browser to view that page over the Internet. You can also view pages by way of hyperlinks, or simply links, which are click-able words or images on Web pages. Every link on a Web page is associated with a URL that leads to another page on the Internet. Users can jump from one Web page to another by clicking links.
Browsers
A Web browser is software that allows you to view and interact with Web pages. When you type a URL or click a link in a Web browser, the browser retrieves the appropriate page from a server on the Internet and displays that page. Microsoft Internet Explorer, Mozilla Firefox, and Apple Safari are the three most popular browsers in use today. Each program has evolved through a number of versions, with newer versions supporting more recent Web features. As you build your pages using
HTML code, remember that different browsers may display your pages slightly differently depending on the version.
