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On the other hand, the fast distribution of system so naturally uniting diverse resources, was promoted not in the last instance by its(her) origin not in недрах of a business concern, and in scientific establishment - European laboratory of physics of particles, which employees did not begin to do(make) of secrets of the development and have not tried at all on it(her) to grow rich.
Fortunately, nature WWW as first of all means of search and organization of the information allows to hope, that this remarkable invention to not turn to the tool of only one commerce and advertising.
The servers and clients WWW communicate among themselves under the special protocol HTTP (Hyper Transfer Protocol, hypertext transfer protocol). URL for WWW looks as:
http: // < the address of the server >
To pass from one page Web to another - an interesting way of research World Wide Web, however you early or late need to find something concrete. But thus it to make it will be not possible. In Internet there are special tools of Web-search.
Tools of search in WWW.
Tools of search of the information in Internet, constructed on different principles and pursuing the different purpose, exists much. But all unites them that they settle down on the specially allocated network computers with powerful channels of communication(connection), serve every minute huge quantity(amount) of the visitors and require(demand) of the owners of significant expenses on support and updating. Nevertheless, almost all of them respond on searches of the users completely бескорыстно, and the sponsors and advertisers pay for this pleasure. On scales of influence on network community of retrieval systems, undoubtedly, are one of corner stones Internet.
The classification of retrieval systems is more convenient for building all on the basis of on the tax and processing of the information given to the users, - or else how many is automated in them, who types(collects) a database, in which the search is made: the people or computers.
2. Tools of search
Conditionally tools of search are subdivided into search means of a help type (directories) and retrieval systems in the pure state (search engines).
2.1 Thematic catalogues
The search tools of the first type name subject, or thematic catalogues more often. The company owning such catalogue, continuously conducts huge work, investigating, describing, cataloguing and displaying on half-glasses contents of WWW-servers and other network resources scattered worldwide. Result her(it) titanium of efforts is the constantly updated hierarchical catalogue, at the top level the most general(common) categories, such as “business” are assembled, "”science", "”art" etc., and the elements of the lowermost level represent the links to separate WWW-pages and server together with the brief description of their contents.
Guarantees that such catalogue really covers all contents WWW, nobody will give, however possible(probable) not the completeness and selection of materials is with interest expiated there, that for the present not under force to any computer - intelligence of selection.
The subject catalogues give also opportunity of keyword search. However search this occurs not in contents of WWW-servers, and in their brief descriptions stored(kept) in the catalogue.
The subject catalogues Internet can be counted literally on fingers, as their creation and support require(demand) huge expenses. To most known concern Yahoo, WWW Virtual Library, Galaxy and some other.
Yahoo.
Is most popular in the population Internet the catalogue Yahoo. On the first page Yahoo, located to the address http://www.yahoo.com, you receive access to two basic method of work with the catalogue - keyword search and hierarchical tree of sections.
Having begun descent(release) on sections of the catalogue, you will see, that each section contains the precisely same field for input of keywords and button Search, starting search.
Each section can include as transfer included in him(it) and actually links to pages concerning at once all section, with their brief descriptions.
Реферат опубликован: 5/12/2009