Often they are mixed, considering synonymous. In fact, they represent three different levels of the construction of World Wide Web. Without resorting to rigorous definitions, we agree to understand a page of a document displayed as the contents of a single browser window. Then the site can be defined as a set of several Web pages that are linked into a single structure by means of hyperlinks. This is usually one of the pages (with name index, or welcome) is a major, start: that it gets Internet user who receives the browser to the site. Other pages can be called from main or from each other. Server is the concept, rather, the hardware: this is usually a permanently connected to the Internet computer disk that stores one or more sites. Thus, physically, the Internet is a set of connected computers in a network server, the disk of each of which can be placed one or multiple sites, each site will, in turn, may consist of one (in the simplest case) or several Web- pages. Internet sites may be free and commercial. Many users believe that the Internet and World Wide Web interchangeably. In fact, it is not. Internet is a global communications network linking many computers connected to it servers. At the same timeservers provide users with various kinds of services, resources, or e-mail, newsgroups and chat rooms, WWW, as well as less popular Gopher, Usenet, etc. Thus, World Wide Web is just one of the services on the Internet. Strictly speaking, WWW is an interactive multimedia hypertext environment that uses the language of HTML markup and supports many Internet protocols. Thanks to the versatility and convenience of World Wide Web has become the most popular resource on the network, increasingly displacing other types of services. Internet is hierarchical network integration at lower levels (from national to local). Hence, for the effective exchange of information between computers connected to different networks, you must use the same format and methods of sending and receiving data. To this end, a series of rules (standards), known as protocols developed. Among them are most important to users of WWW protocols are TCP / IP (Transmission Control Protocol / Internet Protocol) and HTTP (Hypertext Transfer Protocol). The first provides for the exchange of information between any two computers on the network regardless of the model and type of operating system and the second transfers the data in World Wide Web. Note that at present the scope of the WWW technology is not limited to Internet and network applications. Usability of hypertext documents led to widespread use of Web-standard in the development of various types of user shells, such as databases, reference books and encyclopedias on CD-ROM, etc.
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