INTERNET BASIC

A Brief History of the Internet In 1969, the US Department of Defense started a project to allow researchers and military personnel to communicate with each other in an emergency. The project was called ARPAnet and it is the foundation of the Internet. Throughout the 1970's, what would later become the Internet was developed. While mostly military personnel and scientists used it in its early days, the advent of the World Wide Web in the early 1990's changed all that. Today, the Internet is not owned or operated by any one entity. This worldwide computer network allows people to communicate and exchange information in new ways. According to www.commerce.net, in April of 1999, there were 92.2 million Internet users over the age of 16 in the United States and Canada. By 2005, it is predicted 75% of the total US population will be online The Internet is the largest computer network in the world, connecting millions of computers. A network is a group of two or more computer systems linked together. There are two types of computer networks: Local Area Network (LAN): A LAN is two or more connected computers sharing certain resources in a relatively small geographic location (the same building, for example). Wide Area Network (WAN): A WAN typically consists of 2 or more LANs. The computers are farther apart and are linked by telephone lines, dedicated telephone lines, or radio waves. The Internet is the largest Wide Area Network (WAN) in existence. Servers All computers on the Internet (a wide area network, or WAN) can be lumped into two groups: servers and clients. In a network, clients and servers communicate with one another. A server is the common source that : Provides shared services (for example, network security measures) with other machines and Manages resources (for example, one printer many people use) in a network. The term server is often used to describe the hardware (computer), but the term also refers to the software (application) running on the computer. Many servers are dedicated, meaning they only perform specific tasks. For example, An email server is a computer that has software running on it allowing it to "serve" email-related services. A web server has software running on it that allows it to "serve" web-related services. Clients Remember, all computers on the Internet (a wide area network, or WAN) can be lumped into two groups: servers and clients, which communicate with one another. Independent computers connected to a server are called clients. Most likely, your home or office computer does not provide services to other computers. Therefore, it is a client. Clients run multiple client software applications that perform specific functions. For example, An email application such as Microsoft Outlook is client software. Your web browser (such as Internet Explorer or Netscape) is client software. Servers and Clients Communicate Your computer (client hardware) is running a web browser such as Internet Explorer (client software). When you want to surf the web, your browser connects to a remote server and requests a web page. The remote server (server hardware) runs web server software (server software). The web server sends the web page to your computer's web browser. Your web browser displays the page.