Each website has an individual address which is called a Uniform Resource Locator. In reality they are numbers but we use names, as they are easier to remember.
org refers to the fact that it is an organisation
[.co.uk is an UK company
.com also refers to a company]
Future concerns for the Internet include the efficiency of search engines. Search engines search websites for criteria a user is looking for. Even the most efficient of them cover less than a sixth of all publicly available pages as well as privacy, security, and Internet piracy.
The Internet has given us a new way to communicate with each other through the use of E-mail. This allows a message to be sent from one person to another, or to many others, via computer. Internet has its own e-mail standards that have also become the means of interconnecting most of the world's e-mail systems.
E-mail can be distributed to lists of people as well as to individuals. A shared distribution list can be managed by using an . Some mailing lists allow you to subscribe by sending a request to the mailing list administrator. A mailing list that is administered automatically is called a .
E-mail is one of the protocols included with the Transport Control Protocol/Internet Protocol () suite of protocols. A popular protocol for sending e-mail is and a popular protocol for receiving it is . Both Netscape and Microsoft include an e-mail utility with their Web browsers.
FTP (File Transfer Protocol) is a set of conventions allowing easy transfer of files between host computers. This remains the biggest use of the Internet, especially for software distribution, and many public distribution sites now exist.
Internet Relay Chat (IRC) is a system for that involves a set of rules and conventions and software. On the Web, certain sites such as Talk City or IRC networks such as the provide and help you download an IRC to your PC. You can start a chat group (called a ) or join an existing one. There is a protocol for discovering existing chat groups and their members. Depending on the type of network, nicknames can be reserved (registered) or just used during the session. Some channels encourage you to register a nickname that you always use and even offer space for a personal profile, picture, and personal home page link.
In order to be able to view Web pages you need a piece of software called a browser. The most popular browsers are Microsoft Internet Explorer and Netscape Navigator.
Browsers allow users to navigate through the Internet easily. A Web browser is a program that uses to make requests of Web s throughout the Internet on behalf of the browser user.
A browser forms a connection to a Web server, requests a page and receives it. To do this the browser breaks a URL into 3 parts:
- The protocol ("http")
- The server name ("www.wimbledon-college.com")
- The file name ("web-server.htm")
The browser communicates with a to translate the server name into an IP Address, which it uses to connect to the server machine.
This diagram shows how a computer connects to the Internet.
A home computer is usually linked to the Internet using a normal phone line and that talks to an Internet Service Provider (ISP). A computer in a business has a Network Interface Card (NIC) that directly connects it to a Local Area Network (LAN) inside the business. The business then connects its LAN to an ISP using a high-speed phone line like a T1 line. A T1 line can handle approximately 1.5 million bits per second, while a normal phone line using a can usually handle 30,000 to 50,000 bits per second.
When a computer user accesses a site on the World Wide Web, he or she is presented with a screen of information called a page. An organization usually maintains a home page, the “master page” from which other pages can be reached by a series of branching pathways. The user can make the jump to another page by “clicking on” a highlighted “hot spot.
Internets are constructed using virtually any kind of electronic transmission medium, such as optical-fibre or copper-wire telephone lines, or radio or microwave channels. Modem devices that convert between analogue and digital signals. Digital signals, which are used by computers, are made up of separate units represented by a series of 1s and 0s (bits). Analogue signals vary continuously; an example of an analogue signal is a sound wave. Modems are most frequently used to enable computers to communicate with each other across telephone lines. To convert a digital signal to an analogue one, the modem generates a carrier wave and modulates it according to the digital signal. There are many different kinds of modulation, depending on the application and the speed of operation for which the modem is designed.
Some modems have become specialized in terms of function. For instance, one of the cards available for a PC is a facsimile transmission (fax) modem that allows the PC to talk directly to fax machines and to send and receive fax messages. High-speed modems have been developed that work at speeds of 2 megabits per second. These are used as components in leading-edge communications services and are not as yet commercially available.
Safety factors and the Web
Before letting children loose on the Web you should consider the following
- The need for the school to develop an Internet policy
- The need for parents to sign a consent form as part of acceptable behaviour policy
- Censorship and obligations of unsuitable material
- Supervision of pupils as they use the Internet
- Never publish the name, address or e-mail of a child on the Web and don't identify a single child
