Рефераты. Internet



One of the main differences of the Internet from all rest, that is

connected to computers, is that for successful work with it(him), generally

speaking, it is not necessary of any books. Internet can serve both

directory, and tutorial, and encyclopedia itself. However on the initial

stage, as it seems, the advantage(benefit) of the book, distinctly and is

accessible of a stating basis, can be rather significant. Such book I also

have tried to write. But before you will get acquainted to it(her) more

close, let's try to answer on the most important question, which, probably,

you already set to yourselves:

The Internet: that it, at last, such

More or less scientific definition of the Internet, which the books and

clauses on this subject are filled, certainly with, have the value. But the

most simple explanation suffices for our purposes while: the Internet is a

set of computers connected with each other by channels of

communication(connection), plus a set of standard rules, on which they

exchange by the information. Thus channels of communication(connection),

perhaps, even are less important, than rule of data transfer on them, named

in the Internet by the protocols. If even two computers cooperate on one of

such protocols is already present Internet.

The invention and the perfection of modems - special devices allowing the

computer to send the information on the phone, - has opened doors in the

Internet to huge quantity(amount) of the people, at which is not present.

Any special network equipment, and there is only personal computer and

telephone socket nearby.

Both Internet, and the modems for personal computers exist already rather

long. However only at all for a long time - about 1990 - the Internet has

typed(collected), at last critical weight of the users and resources

necessary for network revolution, occurring on our eyes. The high-speed

modems allowing the usual users of personal computers without restrictions

to enjoy by all boons of the Internet, have appeared even later. And the

system World Wide Web (WWW, or "«World wide web"), invented in 1993 and

former firstly only by one of many components of a network, has

borrowed(occupied) a leading position and began to define(determine) the

person of the Internet literally in last years - two. By and large, the

world Internet boom now in the heat - and very much was lucky(carried) to

you, that you were not late almost to the beginning of performance.

The Internet is, first of all huge set of computers and programs. Among

last you will find not only such, which are able well to decide(solve) your

concrete tasks, but also is greater such, whose abilities it will be

firstly complex(firstly difficult) even to present to you, probably. The

Internet connection gives you a unique opportunity, what imperfect was your

computer to have a look per the twenty first century and independently to

accustom with such concepts, as « world cyber – social », « virtual money

», « information environment(Wednesday) habitation». Item, - word, with all

of subjects, about what so love to write now journalists.

However it only part of the answer on a question « that such the Internet

». The Internet today is not only huge quantity(amount) of computers, but

also the improbable quantity(amount) of the people, for which network is an

essentially new way of dialogue almost not having of analogues in the

material world. The man - essence social, and dialogue with itself similar

- one of his(its) first needs(requirements). Perhaps, till now still any

technical invention (short of the telephone) does not make such revolution

in this ancient as the world employment(occupation) - dialogue of the man

with the man.

Certainly, what exactly will interest you in the Internet first of all -

people or computers, - depends only on you. The ancient metaphor of the

book as models of world, perhaps, deserves reconsideration - now on a role

of such model computer approaches much better. When the speech goes about

millions computers and their users all over the world, connected in a

uniform network, the metaphor this already ceases be simply metaphor. That

is why by exaggeration will not tell, that, leave in the Internet, you do

(make) for yourselves accessible the whole world.

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


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 >


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


But how to learn(find out) where to address in searches of the necessary



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.

Archie the list into the list into the list into the list into the


URL-address indicating FTP-connection, owes, as a minimum to include a word

“ftp” as the left part and address of the site in right:

ftp: // < the address of the server >.


Almost all information resources Internet give an opportunity of automatic

search, but only in one of them - in system WAIS (Wide Area Information

Server, global information server) - the keyword search, is the basic

method of access to the information.

The system WAIS represents the huge distributed(allocated) database, i.e.

the separate parts of this database are located on different net points

worldwide. The program - client for work with servers WAIS not only is able

to communicate with them under the special protocol, but also stores(keeps)

the list of all databases WAIS with their addresses and names, and

sometimes and with the brief descriptions. There it is possible to find

archives of news, every possible catalogues, directories, collections of

scientific clauses and abstracts, indexes and much another. Practically any

information, for which the database is the convenient form by performances

which is interesting enough to a wide audience, can be submitted in WAIS.

The database WAIS is so great, that idle time of recordings - extremely

unpromising way of access to the information. Therefore in WAIS the rather

complex(difficult) method of keyword search and phrases is applied. The

documents received as a result of search, are sorted by the WAIS-server by

quantity(amount) of entry in them of keywords and on, as far as is complete

in each of them all set of the ordered keywords is submitted. Such system

is capable to give good results, is especial if to break process of search

at some stages.

The first stage of search usually is the search special in a database under

the name “directory-of-servers”, which contains small on volume of the

description (abstracts) of all other bases WAIS. Thus it is better to

specify not those keywords, which at the end interest you, and those

general(common) concepts concerning your field of knowledge.

Having chosen on the first stage of one or several bases, it is possible to

begin search actually of documents - that also it is possible to do(make)

in some calls, getting acquainted after each search with results and

changing the list of keywords, the necessary document will not be found

yet. Besides WAIS has one useful property: if at the next stage of search

you have found the document, which contents are especially close that you

search, it(he) can be added to the list of the relevant documents. In

result at the following stage WAIS will find the documents, not only

containing a set of your keywords, but also similar on the dictionary

structure on those texts, which you have specified as most suitable.

Though Netscape is capable to work with servers WAIS, for this purpose

it(he) should know the address of the special proxy for the protocol WAIS,

of which your provider can not appear. The special WAIS-clients working

including under Windows, not only convenient for interactive search in

databases, but also allows to manage services any of the server –


URL-address for WAIS looks as:

wais: // < the address of the server > / < the name of base >


Each of the considered till now Internet protocols quite could exist in

itself: telnet gives access to the programs, FTP - to files, WAIS - to

databases. All these systems were created both developed almost

independently from each other and put before itself the concrete purpose -

to construct the mechanism of access to one certain kind of resources.

However as Internet of dews also became complicated, it(he) pushed the

people to an idea, that the information on a nature is uniform and what not

too reasonably to divide her(it) on different “ kinds of resources ” with

unlike methods of access. By the end of 80-s' years the idea of a new

universal remedy of work with the diverse information was carried in air.

The first system called to embody for life these dreams began Gopher,

appeared on light 1991 at the American university of state Minnesota.

Fundamental concept incorporated in its(her) basis was structure enclosed

each other menu.

Having communicated Gopher- by the client with one of Gopher-servers, you

first of all get in the root, main menu of this server. Having oriented in

his(its) contents and passing further from one submenu in another, it is

possible to engage actually in search of the information. The information

in system Gopher is organized strictly hierarchically, “from the general to

the particular”. On each step the server sends yours Gopher - client not

only contents of the next menu, but also service information on, where

there are objects appropriate to items it the menu. The client deduces on

the screen only transfer of items, but when you choose one from them,

it(he), having verified with the information, available at him(it), or will

send on any of Gopher - servers search about distribution of the following

of the menu, or will try to establish FTP- or telnet- connection with some

site Internet.

Obviously from all information tools Internet Gopher most of all is similar

on WWW - both these systems are called to serve the shell with diverse

resources. However Gopher is deprived of those rich representational means,

which do(make) WWW not only information catalogue, but also new mass media

and even by a new genre of art. It is possible to tell, that Gopher is

“subset” WWW - that very much simplifies integration itself Gopher as one

of kinds of resources in WWW. Practically all that is told about work with

Gopher - by the client fairly and for travel on system Gopher with the help

of a browser WWW.

URL of one the menu consists of items Gopher - from addresses Gopher- of

the server and listed those items of the menu, which will result you in

initial item:

gopher: // < the address of the server > / < item of the menu >


In spite of the fact that per the first years of the existence Gopher has

won the large popularity, the need in any became ripe more simple and in

too time to maximum universal system, in which communication(connection)

between resources would be more free and associative. Such system was

developed in 1993 and is named World Wide Web (WWW). System WWW to be under

construction on concept of a hypertext, or, is exacter than hypermedia. The

hypertext is a text of which component are connected with each other and to

other texts with the help of the links. The hypermedia is that that will

turn out from a hypertext if to replace in his(its) definition a word

“text” on “ any kinds of the information ”: the graphic images, video,

sound etc.

World Wide Web “world wide web” means literally. Why she(it) so refers to

as. As it is clear from the name, she(it) is global. You not always know in

what part of light there is a computer, to which you are connected. You can

begin to read page Web in Dallas, then to proceed(pass) in Australia, and

all this on one pressing of the button of the mouse. WWW is similar to a

web. It is a complex(difficult) information network connected hypermedia by

communications(connections). WWW allows to not refuse information resources

already saved in Internet, other means, accessible with the help, - FTP,

telnet and Gopher. It is more than that, the work with these resources

through WWW is so convenient, that, say, FTP-clients, former at one time by

separate class of the programs, now are used only by few.

And nevertheless main in World Wide Web is not convenience of access to FTP-

of archive and Gopher-menu. The majority of servers of system WWW offer

the information, which without WWW hardly in general when or would get in a

network. Speed of creation and updating, the rich representational

opportunities in a combination to ease of access and huge audience have

made WWW by new mass media. The start WWW-servers and creation of WWW-pages

already has turned of a style to new business - with all that is peculiar

to modern business: by a payment for square centimeters of the advertising


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

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