О. В. Фёдорова е. В. Мезина е. В. Хамис английский язык в сфере информационных технологий и коммуникаций учебное пособие

For the users in our country the certain interest can represent the thematic catalogue Russia-On-Line Subject Guide, located to the address http://www.online.ru/rmain. This catalogue contains rather motley assembly of the links on foreign sources plus the thematic review of the Russian and Russian resources WWW.

It is possible to approach to a problem of search of the information in Internet and on the other hand. There are programs in which have loaded some thousand well-known URL-addresses. Being is started on the computer with access to WWW, this program begins automatically to download from a network the documents on it URL, and from each new document she(it) takes all links, contained in it,(him,) and adds them in the base of addresses. As at the end all WWW the documents are connected among themselves, early or late such program will bypass all Internet.

Certainly, the program can not understand as or classify that she(it) sees in a network. The programs of such type refer to as robots. They are limited to the tax of the statistical information and construction indexes in the texts of the documents. The database, collected by the robot, - index - stores (keeps) in it, simply speaking, item of information on that in what WWW-documents to contain those or other words.

Such the automatically collected index also underlies retrieval systems of the second sort, which frequently and name - automatic indexes.

The automatic index consists of three parts: the program - robot collected by this robot of a database and the interface for search in this base, with which the user works. All these components quite can function without intervention of the man.

As any classification of materials in such systems are absent, it is necessary to resort to them only then, when you precisely know keywords concerning that it is necessary, - we shall tell, a surname of the man or it is enough some of rare terms from the appropriate area. If to set search on the a little widespread words, you will have not enough life to bypass all URL-addresses, received as a result of search, - for example, the index of system Alta Vista contains of 11 billions words taken from 30 millions of WWW-pages.

An automatic index of WWW-pages exists much: WebCrawler, Lycos, Excite, Inktomi, Open Text and others. Some of them (for example, Lycos) represent more or less successful synthesis of the subject catalogue and automatic index.