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1. Basic protocols in Internet and search in them.
Internet contains vast quantity (amount) of the information, on this in it(him) it is difficult to find that that is necessary if not to know where to search. The place of a presence(finding) (or address) each resource defines(determines) it(him) URL. In URL the type of the protocol indicating on what server contains the access is carried out: on WWW (on which specifies recording: http), Gopher, ftp, telnet, or WAIS, it depends on that what type of the information you will transfer. The network protocol - set of the precisely certain rules: how to request, to make out and to send on a network the given version of the information
telnet
Millions computers are joined(attached) to a network Internet and many from them have interesting opportunities.
It appears, is quite feasible to reach these computers to look databases, available in them, and programs. The special program telnet allows to transform your computer into the client telnet for a data access and programs in numerous servers telnet. For example researcher regularly can work on several computers, which managers nominate to it(him) a special name and password.
In itself telnet - the communication facility is simple; neither any of the own interface, nor opportunities of search it(he) does not give.
Having contacted the help telnet with the removed machine and having entered in a field of search the entrance name (login) and password (password) you communicate with this machine and programs on further to it(her), and telnet cares only of maintenance of communication(connection) between you.
Certainly, many storehouses of the information, which were originally served by the special programs with access on telnet now it is possible to transfer(translate) on WWW, that not seldom and is done(made). However there were also such which on former give the services only on telnet (especially among the catalogues and information services of libraries).
Standard the link on telnet connection with some site Internet (i.e. URL- the address of this connection) looks so:
telnet: // < the address of the server >
FTP
Practically information is stored(kept) in the computer world as files. On this for itself заре Internet the special means for an exchange of files on a network - network protocol FTP (File Transfer Protocol) has appeared.
The quantity(amount) of files accessible on sites of all world on anonymous FTP is measured in astronomical figures and constantly grows. Besides Word Wide Web allows without any alteration existing FTP of archives, to supply with their descriptions of any degree of detail and convenient hypertext interface.
But how to learn(find out) where to address in searches of the necessary file?
Archie.
The search on a name of a file on all anonymous FTP-sites of the world can be carried out with the help of system Archie. She(it) is developed by the several programmers from university Magellan in Canada and carries out indexation of stations FTP, showing files, accessible in everyone station. Archie informs several millions files taking place in more thousand stations FTP, and gives a surprisingly fast way of search of that place, where it is necessary to be directed for reception of a file, interesting for you. The search in a database of the server Archie is made with the help of keywords, which in this case represent simply names of files or fragments of names.
Now Archie is accessible through WWW. It WWW page with the form in which the keywords and options of search are specified.
Though the name of a file almost always has a certain attitude(relation) to his(its) contents, to use Archie for thematic search of the programs does not cost. This system will be useful, if you really know a name of the necessary file or part of a name. On the other hand if you search for the program, which has the standard reduced name, that is some probability that this reduction will be present and at a name of a file, so it is possible to try to find such file with the help Archie. The results of search represent the list of FTP-sites and complete names of files on these sites. The name of a file serves the link to this file, so the click on a name will allow at once receiving a file from the given site. And domes the address of FTP-archive allocated by a large greasy font will transfer you to the initial catalogue of file system on this archive.
Реферат опубликован: 5/12/2009