Week 3:The Internet and World wide web

The Internet:

One of the major reasons business, home, and other users purchase computers is for Internet access. The Internet, also called the Net, is a worldwide collection of networks that links millions of businesses, government agencies, educational institutions, and individuals. The Internet is a widely used research tool, providing society with access to global information and instant communications. Today, more than one billion home and business users around the world access a variety of services on the Internet, some of which are shown in Figure 2-1. The World Wide Web, or simply the Web, and e-mail are two of the more widely used Internet services. Other services include chat rooms, instant messaging, and VoIP (Voice over Internet Protocol). The Internet has its roots in a networking project started by an agency of the U.S. Department of Defense. The goal was to build a network that (1) allowed scientists at different locations to share information and work together on military and scientific projects and (2) could function even if part of the network were disabled or destroyed by a disaster such as a nuclear attack. That net work, called ARPANET, became functional in September 1969, linking scientific and academic researchers across the United States. The original ARPANET consisted of four main computers, one each located at the University of California at Los Angeles, the University of California at Santa Barbara, the Stanford Research Institute, and the University of Utah. Each of these computers served as a host on the network. A host or server is any computer that provides services and connections to other computers on a network. By 1984, ARPANET had more than 1,000 individual computers linked as hosts. Today, more than 550 million hosts connect to this network, which is known now as the Internet.