Information technologies on the Internet. How GCS technologies developed. The inevitability of the Internet
In the first chapter, we considered the Internet as an object of the concept of information and computer science as part of the corresponding concept and conceptual apparatus. IN in this case We'll look very briefly at the Internet as technical means storage and transmission of various information, as a type of information technology. This technology, called World- Wide Web, or WWW for short, was able to bring the system of information use to a new level, opening up radically new possibilities for its application in different areas of life - science, education, business, etc.
The history of the formation of the Internet is still short, but it is already rich in scientific events. For the first time about information age they started talking about a real prospect for the development of mankind in connection with the creation in 1888 by W. Burrow of the first calculating machine capable of adding in a short time big numbers"Two years after this, G. Hallreith built a machine that received tasks on perforated cards. In the middle of the 20th century. X. Aiken ( Harvard University) built an “automatic computer with a control sequence” (weighing about 4.5 tons) - “MARK 1”. Almost simultaneously with this, scientists from the University of Pennsylvania J. Eckert and J. Mauchly created the first electronic computer ENIAC", and J. von Neumann proposed a binary calculus system for controlling such machines. In addition, this scientist developed the principle of entering and storing in the machine not only data, but also commands to control its actions.
However, the growth in the production of computer technology no longer met the needs of society on its own. Local networks, database management systems and even multimedia technologies were used mainly as a tool for internal automation of individual companies and firms, and the computers themselves worked in isolation from each other. Therefore, the next stage in the creation of computer technology is associated with the emergence of global computer networks, which have greatly increased the information capabilities of individual computers. A special role in this was played by the fact of worldwide recognition of the international computer network Internet. The Internet has provided an opportunity for millions of people from dozens of countries to unite, and has destroyed barriers to communication, exchange of scientific and cultural information, etc.
The history of the global network began in the 60s. last century, when the US Department of Defense was given a strategic task: to develop a system for managing the country in the event of a nuclear conflict with the Soviet Union. American strategists assumed that a possible nuclear strike would be delivered to the US national communications center (the center of communication between the country's military leadership and US strategic forces). A department of the Department of the Ministry of Defense known as ARPA (Agency research projects special difficulty). The result of the research was the creation of a decentralized network consisting of separate independent segments. Information exchange within this network was ensured by an original design - dividing information data into small portions, so-called “packets”, each of which reached its destination in different ways, in other words, was supplied with a corresponding address. If for some reason it did not reach the recipient or was distorted during the transmission process, it was transmitted again."
The first documents that gave the technical characteristics of the system were published in 1964, and already in 1969 the first four computers formed a small but truly functioning network, which became known as ARPANET. This network can rightfully be considered a prototype of the Internet. In 1971, it already included 14 computers, and in 1972 their number approached 37. 70s. were devoted to the expansion of the computer network and the improvement of the internetworking mechanism within the ARPANET project. In 1982, the Transfer Control Protocol and Internet Protocol received wide publicity, the terminological abbreviations of which - “TCP” and “IP” - have since entered the professional language of programmers and have traditionally been assigned to all types of documents and standards used in the ARPANET and a little later on the Internet. The global information network itself, the Internet, was the result of a grandiose computer project of the US National Science Foundation (NSF).
For research purposes, a number of computer centers were organized in America, equipped with the latest computers at that time. In order to facilitate access to the resources and computing programs of these centers for scientists conducting important research, it was decided to combine them into a single computer network. Since the use of the ARPANET defense network for these purposes was prohibited for known reasons, the Foundation implemented a similar project, which resulted in the creation of the NSFNET network. The basis of the scientific information network was ready-made mechanisms for information exchange, tested during the operation of ARPANET.
Around this time, the first six domains of the Internet emerged, such as: gov, mil, edu, com, org and net. These abbreviations are deciphered as follows: “gov” - indicates a network of government organizations, “mil” - indicates the military; "edu" - denotes educational resources of universities; “org” refers to non-governmental and non-profit organizations, and “com” refers to a network of commercial structures. The “net” domain is assigned to institutions responsible for the operation and development of the global network as a whole.
In 1993, when the number of connected servers exceeded a million, the Internet acquired the form that is familiar to us today, and at the same time the task of universal, global informatization of humanity was proclaimed. It was in 1993 that then new multimedia technologies began to be increasingly used within the Internet. Both the private commercial sector and government agencies quickly appreciated the advantages and opportunities global system communications and actively participated in its development. At the same time, academic institutes and educational centers contributed significantly to building up the information potential of the Network.
The Internet was originally conceived and maintained as accessible to everyone, and this was one of its main advantages. In practice, it is only necessary to pay for the services of local providers; the exchange of information, search and other useful innovations within the Network are free. This provided a massive influx
to the Internet of ordinary users of personal computers. Exact number of users global web It is impossible to establish, but it is known that every year their ranks are replenished with several tens of millions of members.
The Internet emerged on Russian soil in the early 80s, and the Kurchatov Institute was the first in our country to gain access to the world’s information treasury. IN last years The Internet includes both the Network itself and the entire complex of programs and technologies operating on it, turning it into a new economic and social environment. The popularity of the Internet in Russia is growing rapidly: the growth in the number of users is about 10% per month, and this is far from the limit.
Currently, the Internet is a world of communications, scientific and cultural information, a meeting place, an entertainment industry - in a word, a world for which the concept of “distance” does not exist. The Internet, or the World Wide Web, is a distributed knowledge base consisting of various information arrays connected to each other by cross-border telecommunications. Using Internet resources is quite simple; for example, you do not need to have the skills to implement network protocols in order to work with the information they are interested in.
So simple and convenient tool connection we owe to Tim Berners-Lee, who suggested new way transfer of documents and establishment of contact. Its essence lies in the use of a system of hypertext links that connects arbitrary points of graphic or text documents such as WWW, as well as components of these documents, to each other. They are provided in HTML format and may also include graphics and text fragments, design elements, individual data and other similar structures. The uninterrupted operation of the Internet is ensured by countless “providers”, or owners of “servers” (the so-called main computers on which information reserves are actually stored).
The WWW project was initially carried out at CERN, the European center for high energy physics, but gradually moved beyond the close confines of the community of physics scientists. The first programs showing the potential of the system were completed in 1992 and were calculated for NeXT series computers. It took WWW technology very little time to conquer and master almost all available operating platforms, including even the “antediluvian” MS-DOS.
Although workplace WEB technologies are the Internet; this does not mean that they cannot do without each other or be used separately. On the contrary, it is quite acceptable to run a WWW project as a local information system, since the data formats and protocols it contains are not related to the technological basis of the Internet (IP). But since any information system, besides technical capabilities, is attractive, first of all, for its content and ease of management (interface), it was the Internet, with its scale, openness and structure, that made the “web” technology a global asset.
In addition to the ease of managing benefits WEB systems are the ease of navigation in the global information space and the ability to seamlessly connect and combine different multimedia objects into one whole. Thus, the classic all-in-one web browser is in demand by almost all popular information services on the Internet. The motto of the World Wide Web - “simple and brilliant” - is perfectly confirmed by the fact that from 60 to 75% of users spend an average of no more than 6 hours learning the WWW language - HTML and its varieties. HTML language, from a purely practical point of view, is markup made of ordinary English words within a document, and was created to make documents stand out logical structure. HTTP protocol so simple that it sometimes even interferes with the organization of an information service. Its essence lies in creating a framework of communication between the navigator and the WWW server. One operation easily fits into the request-response scheme. The simplest example: the navigator requests a certain document, and the server provides it. Also, http technology is not a puzzle (HyperText Transfer Protocol), which is the basis of hypertext links.
Each user must have his own domain name, which is used to name and indicate the address of the site on the Internet. A domain is an area of the hierarchical domain name space on the Internet, which is designated by a unique domain name. A domain name is an address network connection, which identifies the owner of the address. The domain name must be unique within one domain; two identical domain names are not allowed to exist on the network. It is used to address Internet nodes and those located on them. network resources(sites, servers Email, network services) in a form convenient for humans. An alternative would be to address the host by IP address, which is less convenient and harder to remember.
What is Domain name as an information object? First of all, as noted above, this is the address of the location of the information resource on the Internet. In this regard, as in the case of a postal address, it is necessary to respect its uniqueness and originality. This condition This can be done by registering a domain name. At the same time, the meaning embedded in it (as well as the absence of it) does not matter for identification purposes.
If in the material material world the content of the address does not have great value, then in the virtual world, as it turned out, this fact is very significant, as proven by the events of the last few years. In particular, disputes regarding the legality of using any business names or well-known trademarks as a domain name have received wide publicity.
The difference in the use of addresses on the global network and in the real world lies in the specific functioning and purpose of the Internet environment, which radically changes the whole meaning of the process of disseminating information. The ultimate goal this process is, of course, conveying its content to the addressee/consumer. In the material world this is done by physical actions a certain subject. Information can be disseminated both to specified addresses and as a result of sending messages to an unspecified circle of persons. This method of conveying information to a potential consumer is called active.
It should be noted that the idea that you can independently find any information on the Internet is an illusion. The information space of the network is too extensive for the average user to get acquainted with all available databases, even taking into account local auxiliary search services. In this regard, one of the urgent areas of activity to improve the network was the creation of various commercial search engines. information services. The latter consist of branched (based on the principle of hierarchy) lists of information resources and resemble the subject-content catalogs of most libraries. Typically, the presented electronic catalog organizes lists by sector, also having a special system for processing requests using keywords or word forms. Users can choose the search principle at their own discretion. For beginners, it is rather more convenient to use the subject catalog: going down through it, sooner or later you can come across the necessary links. The only thing that needs to be taken into account when this type search is that the concepts of the content of a particular thematic area and the terms inherent in it, inherent in the developers of information services and interested users, do not always coincide. While a person gets used to working with online search services, he inevitably spends a lot of time on unnecessary ones. review procedures related to the inaccuracy of your request. However, the same problem is also typical for the initial stage of working with traditional catalogs and archive lists. Manufacturers of online information catalogs are constantly trying to improve the principles and parameters of search in one way or another, but so far the existing search systems are very, very far from perfect.
Among other things, various ordering mechanisms that exist on the Internet are characteristic of national information resources. Sometimes they are based on the administrative division of the country, and sometimes on belonging to one or another sphere of life. This applies, for example, to educational resources, government, business - information systems distribution information resources and providing them to users.
Search necessary information on key elements is a mandatory service of any network information directory. For this purpose, there are special fields for entering keywords, and when forming queries between them, linking words are used - “or”, “and”. The use of the conjunction “and” implies that all entered words must be present in the required document, and “or” indicates the possibility of an alternative to these elements. The search page can appear simultaneously home page information catalog (an example would be the Yahoo system) or be “tied” to it, open on its own (as is practiced in Galaxy system). Advanced user search services, when creating an electronic request, can not only be limited to introducing a number of signal words, but also use more complex shape search - up to indicating the parts of documents in which to search. The results of information retrieval services are displayed in the form of a list of document titles that meet the specified criteria. The final list, on the one hand, belongs to the “Web family”; on the other, the page that carries it is not recorded in network resources. It is instantly, on the spot, produced by the navigation program, although in most cases, of course, it can then be saved by the user.
The Internet environment is often called virtual, implying the physical intangibility of information - the key object of this environment. Often virtual is defined as possible, which can or should appear under specific conditions, or conditional, apparent. This definition does not fully disclose the essence of the concept “virtual” in relation to the Internet. Thus, information encoded using numbers and stored in a computer becomes visually perceptible and quite real when displayed on a monitor and, even more so, when printed. Thus, information is not “apparent”, but actual reality, which can be confirmed in material form.
And yet, the relations of users or subjects of the Internet, both virtual, differ from the relations of users in the system, so, say, physically real ones, which leads to some peculiarities, for example, in the field of law, etc.
Many researchers of this problem are unanimous in the following: the further progress of information and telecommunication technologies related to the Internet depends not so much on new discoveries, but on how quickly people can adapt the old rules governing the activities of various sectors of telecommunications, television and media to new conditions . This is a very important point, because rapid development new technologies are leading to fundamental changes in information sphere at a qualitatively different, global level. In other words, the revolutionary influence of the Internet extends to government agencies. to economic and social sphere; covers science and culture, institutions of civil society and the entire way of life of people. The Okinawa Charter for the Global Information Society emphasizes that “information and communications technologies are becoming an important driver of global economic development.” Internet technologies are becoming one of the determining factors that provide stable work world markets of information and knowledge, capital and labor, etc.
Interneto
World United System
computer networks built on
using the IP protocol and routing
data packets.
The Internet forms a global
information space, serves
the physical basis for the World Wide Web
and many other systems (protocols)
data transmission. Often referred to as
"World Wide Web" or "Global Network"
Entertainment
80
Purchases
60
Research
40
Job
Entertainment
20
Wandering
0
1
Job
Research
Purchases Currently on the Internet
there is quite a large
number of services,
providing work with
the whole spectrum of resources.
The most famous among
them are:
Electronic mail (E-mail)
o Provides the possibility of sharingmessages from one person to one or
several subscribers
Email - a letter without an envelope
o One of the types information services, whichprovide computer networks, - email
(E-mail). In this case, both subscribers - the sender and
recipient - deal with intermediaries
(providers) performing the functions of local
post offices. Broker server enabled
permanently and officially on his hard drive
registered subscribers are allocated “postal
boxes" for temporary storage of incoming and outgoing
correspondence.
Teleconference
o Provides the opportunity for collectivemessaging
A teleconference is an electronic newspaper consisting entirely of advertisements from its subscribers (electronic bulletin board).
The authors are the network users themselves,united by common interests. Many
providers provide subscribers with a list
conferences. At the same time, you will regularly receive
emails with article titles
relevant topic. You just need to do it
promptly, because the server stores the contents of the next
release about 10 days. oTeleconferencing is very similar to electronic
mail with the only difference that your letter can
read by a huge number of people. Conferences
divided by topic, conference title
consists of several words separated by periods. Here
standard designation for some groups
Usenet newsgroups:
comp - conferences where everything is discussed,
what has to do with computers and
programming;
news - exchange of news, development issues
teleconferencing systems;
rec - recreation, hobbies, interests;
sci - everything related to science;
soc - issues of public life;
talk - a group for those who like to argue
or just talk about any topic.
FTP service
o file archive system,providing storage and forwarding
files of various types
File Transfer Protocol (FTP) – file transfer
o FTP Internet service - gives maximum loadto communication channels. Stands for protocol
file transfer, but when considering ftp as
Internet service refers to access to files on
remote computers and file archives. Her
original purpose - transferring files between
different computers running on TCP/IP networks.
The FTP protocol is, of course, optimized for
file transfer.
Telnet service
o Designed to controlremote computers in
terminal mode
TELNET
o Network protocol to implement textinterface over the network (in modern form -
using TCP transport). Telnet was used for
remote access to the command interface
operating system strings. Supposed,
that this protocol can be used for
terminal-to-terminal connections (“linking”)
or for process-process communication
(“distributed computing”). Subsequently
it began to be used for other text
interfaces, right down to games.
World Wide Web (WWW, W3)
o hypertext (hypermedia) system,designed to integrate various
network resources into a single
information space
World Wide Web or WWW
o This is the most advanced and interestingresource - hypertext navigation system in
Internet. From regular WWW hypertext
differs in that it allows you to independently
establish links not only to the neighboring one
file, but also to a file located on
computer in another hemisphere of the Earth.
o Enables
used for addressing network nodes
mnemonic names instead of numeric names
addresses;
DNS service, or domain name system
o Computer distribution systemfor information about domains.
Most often used to obtain an IP address by name (computer or
devices), obtaining information about
mail routing serving
nodes for protocols in the domain (SRV record).
IRC service
o Designed to supporttext communication in real
time (chat)
Internet Really Chat
o Service system with which you cancommunicate via the Internet with others
people in real time. She was
created in 1988 by a Finnish student. IRC
provides the opportunity for both group and
and private communication. For group chat V
IRC channels are intended for
users can gather and conduct
communication.
Instant messenger
o A program for messaging viaInternet in real time via services
Instant Messaging
Service, IMS). Text messages can be sent
messages, sounds, images,
video, as well as perform actions such as
drawing or playing together. Many of these
programs can be used to organize
group text chats
or video conferencing.
Instant messenger
o A wide range of users know somequantity popular networks messaging,
such as XMPP, ICQ, MSN, Yahoo!. Each of these
networks was developed by a separate group of developers,
has a separate server and protocols, different
with its own rules and characteristics. Between
There is usually no interconnection between different networks
(ICQ network user cannot contact
user of the MSN network, However, nothing prevents
be a user of multiple networks).
Streaming media
o Continuous receipt by the userfrom the provider streaming. This
the concept is applicable both to information,
distributed through
telecommunications and information
which was originally distributed
via streaming
(for example, radio,
television) or
non-streaming (for example,
books, videotapes,
audio CD).
Standard services
The services listed aboveare considered standard. It means that
principles of building client and
server software, A
also interaction protocols
formulated as international
standards. Therefore, the developers
software for
practical implementation are required
withstand general technical
requirements.
Non-standard services
Representing the originaldevelopment of a particular company. As
examples can be given various systems type
Instant Messenger (original Internet pagers - ICQ, AOl, Demos on-line, etc.),
Internet telephony systems, radio broadcasting and
video, etc. Important feature such systems
is the lack of international standards, which
may lead to technical
conflicts with other similar services. As a conclusion, we can say that a local network is not just
mechanical sum of personal computers, it means
expands opportunities and users. Computer networks
allow you to provide the main characteristics:
maximum functionality, i.e. suitability for the most
different types of operations,
Integration consists in the concentration of all
information in a single center,
efficiency of information and management, determined
Opportunity for 24/7 face-to-face work on a real scale
time,
functional flexibility, i.e. opportunity to quickly
changing system parameters,
developed infrastructure infrastructure, i.e. prompt collection, processing and
presentation to a single center of all information from all
divisions,
minimized risks through comprehensive
ensuring security and information, which is subject to
the impact of accidental and intentional threats.
It has long been an axiom that in the 20th century. information has become the most important factor culture. This thesis is confirmed by the fact that special information technologies were created for information processing, the development of which has significantly changed people's lives. Information technology means all computer technology, consumer electronics, television, radio and, of course, the Internet. Issues of information development and information security of society are discussed at the state level. And although the struggle of politicians with the so-called information chaos, for example, through Internet censorship, looks dubious, just as the very concept of information chaos is dubious, it is still obvious that it is impossible to ignore the influence of global information networks on business, politics and daily life impossible.
At the end of the 20th century. The development of information technology has led to the creation of the global information network Internet. In 1969, two remote computers were able to exchange messages - this event marked the beginning of global Internet communication.
From a technical point of view, the Internet is an association of transnational computer networks that connect all kinds of computers, physically transmitting information over all available types of lines. The Internet is decentralized, so shutting down even a significant portion of computers will not affect its operation. Every month the global network increases by at least 10%, more and more computers are connected to it. In developed countries, the Internet is no less accessible than telephone or television. The Internet is influencing the way people communicate, replacing email and even the telephone; but most important function The Internet is providing people with a universal method of accessing any information.
The material basis of the Internet is servers, cables, modems; but the Internet itself is a space of information. If at first the Internet served only educational and research programs, now it is in demand in business, politics, advertising, and art; in addition, it has become a global sphere of communication. In the freely accessible archives of the global network, you can find information on all types of human activity, on all more or less important events, and in a minimum amount of time.
In connection with the emergence and development of the Internet, in modern language new concepts have appeared: cyber culture, cyber commerce, cyber advertising, cyber crime, cyber space; A new section has emerged in psychology - cyberpsychology, which studies the features of cyber communication. The development of Internet technologies has given rise to a number of new problems in the field of philosophy, psychology, and sociology. One of them is a problem virtual communication. Having emerged as a result of the technical revolution and the development of knowledge and science, the Internet became self-sufficient, and its creators ordinary users, just like other "residents" worldwide network. Of course, the Internet has limits, but these are the limits of human capabilities, and they are gradually expanding.
The Internet, like many other technological advances, poses not only opportunities, but also dangers. Desperate critics of the new cyberculture argue that the Internet and the offensive computer technology destroy the culture, way of thinking and way of life of man, their victory will be a disaster for humanity. The main argument is this: computer technology violates the sense of reality, which allows a person to distinguish reality from imagination, reality from illusion. Such changes in consciousness are especially noticeable among fans of computer games: scientists say that every tenth cyber player becomes dependent on a gaming program. In addition to changes in the psyche, this also entails obvious health problems, because the player spends most of the time at the computer, almost motionless, concentrating on the monitor.
Supporters of the spread of computer technology argue that computer games are the same fairy tales that were told to children at all times. Teenagers who are passionate about computer games have an even greater need for communication and friends; they read no less than their peers who are not so immersed in the virtual world, and the behavior of computer game lovers is by no means characterized by increased anxiety or aggression. As for accusations of avoiding reality, it should be borne in mind that just a few decades ago an excessive passion for reading was considered evidence of this; whereas today they claim that children and adolescents read little. The problem lies not in the computer or books, but in the people themselves: for a person deprived of attention, experiencing problems with communication, feeling abandoned and unnecessary, the computer is only a means of escaping reality, but not the reason; the same means can be television, alcohol or drugs. That is, the reason is not that cyberculture captivates people, but the psychological distress of this or that person. Computer games attract both children and adults; they satisfy the need for order in the world, power or control. Many computer games train the intellect and memory, sharpen the will and sharpen attention, teach planning and analysis. On one condition: that they remain means to achieve goals, and not the goals themselves. But the problem of dependence or alienation itself is not generated by the Internet, cyberculture and computer technology.
Modern man lives in a different reality than half a century ago, adapts to it, looks for new opportunities for creativity, experiences fear - real or imaginary, which is inevitable when encountering the unknown. Of course, the development of computer technology gives rise to whole line problems in society (freedom and control, influence and security), changes people's consciousness, and raises the question of the nature of virtual reality. The term “information” itself turns into one of the key concepts of philosophy. Virtualization of culture and consciousness is one of current issues modern philosophy, but acuteness and relevance are not at all a reason for calls to return to the Stone Age.
Today networks and network technologies connect people all over the world and provide them with access to the greatest luxury in the world - human communication. People can communicate and play with friends in other parts of the world without interference.
The events taking place become known in all countries of the world in a matter of seconds. Everyone is able to connect to the Internet and post their piece of information.
Network information technologies: the roots of their origin
In the second half of the last century, human civilization formed its two most important scientific and technical branches - computer and About a quarter of a century, both of these branches developed independently, and within their framework computer and telecommunication networks were created, respectively. However, in the last quarter of the twentieth century, as a result of the evolution and interpenetration of these two branches of human knowledge, what we call the term “network technology” arose, which is a subsection of more general concept"information technology".
As a result of their appearance, a new technological revolution occurred in the world. Just as several decades earlier the land surface was covered with a network of expressways, at the end of the last century all countries, cities and villages, enterprises and organizations, as well as individual homes found themselves connected by “information highways.” At the same time, they all became elements of various data transfer networks between computers, in which certain information transfer technologies were implemented.
Network technology: concept and content
Network technology is a sufficient set of rules for the presentation and transmission of information, implemented in the form of so-called “ standard protocols", as well as hardware and software including network adapters with drivers, cables and fiber-optic lines, various connectors (connectors).
“Sufficiency” of this set of tools means its minimization while maintaining the possibility of building an efficient network. It should have the potential for improvement, for example, by creating subnets in it that require the use of protocols various levels, as well as special communicators, usually called “routers”. After improvement, the network becomes more reliable and faster, but at the cost of adding add-ons to the main network technology that forms its basis.
The term “network technology” is most often used in the narrow sense described above, but it is often broadly interpreted as any set of tools and rules for building networks of a certain type, for example, “local computer network technology.”
Prototype of network technology
The first prototype of a computer network, but not yet the network itself, began in the 60-80s. last century multi-terminal systems. Representing a combination of a monitor and keyboard located on long distances from mainframe computers and connecting to them via telephone modems or via dedicated channels, the terminals left the computer center premises and were dispersed throughout the building.
At the same time, in addition to the operator of the computer itself on the computer information center, all users of the terminals were able to enter their tasks from the keyboard and observe their execution on the monitor, carrying out some task management operations. Such systems that implement both time-sharing algorithms and batch processing, were called remote task entry systems.
Global networks
Following multi-terminal systems in the late 60s. XX century The first type of networks was created - global computer networks (GCN). They connected supercomputers, which existed in single copies and stored unique data and software, with mainframe computers, located at distances of up to many thousands of kilometers from them, through telephone networks and modems. This network technology has previously been tested in multi-terminal systems.
The first GCS in 1969 was ARPANET, which worked in the US Department of Defense and united different types of computers with different operating systems. They were equipped with additional modules to implement communication systems common to all computers on the network. It was on it that the foundations of network technologies that are still used today were developed.
The first example of the convergence of computer and telecommunications networks
GKS inherited communication lines from older and more global networks— telephone lines, because laying new long-distance lines was very expensive. Therefore, for many years they used analog telephone channels to transmit only one conversation at a time. Digital data was transmitted over them at a very low speed (tens of kbit/s), and the capabilities were limited to the transfer of data files and email.
However, having inherited telephone lines communications, GKS did not take their basic technology, based on the principle of circuit switching, when each pair of subscribers was allocated a channel with a constant speed for the entire duration of the communication session. The GKS used new computer network technologies based on the principle of packet switching, in which data in the form of small portions of packets at a constant speed is issued into a non-switched network and received by their recipients on the network using address codes built into the packet headers.
Predecessors of local area networks
Appearance in the late 70s. XX century LSI led to the creation of minicomputers with low cost and rich functionality. They began to really compete with large computers.
Minicomputers of the PDP-11 family have gained wide popularity. They began to be installed in all, even very small production units to manage technical processes and individual technological installations, as well as in enterprise management departments to perform office tasks.
The concept of computer resources distributed throughout the enterprise emerged, although all minicomputers still operated autonomously.
The emergence of LAN networks
By the mid-80s. XX century technologies for combining minicomputers into networks were introduced, based on switching data packets, as in the GCS.
They turned the construction of a single enterprise network, called a local (LAN) network, into almost trivial task. To create it, you only need to buy network adapters for the selected LAN technology, for example, Ethernet, standard cable system, install connectors (connectors) on its cables and connect the adapters to the mini-computer and to each other through these cables. Next, one of the operating systems intended for organizing a LAN network was installed on the computer server. After that, it began to work, and the subsequent connection of each new minicomputer did not cause any problems.
The inevitability of the Internet
If the advent of minicomputers made it possible to distribute computer resources evenly across the territories of enterprises, then the appearance in the early 90s. PC led to their gradual appearance, first in every workplace of any mental worker, and then in individual human dwellings.
Relative cheapness and high reliability The work of PCs first gave a powerful impetus to the development of LAN networks, and then led to the emergence of a global computer network - the Internet, which today covers all countries of the world.
The size of the Internet is growing by 7-10% every month. It represents the core that connects various local and global networks of enterprises and institutions around the world with each other.
If at the first stage data files and email messages were mainly transmitted over the Internet, today it mainly provides remote access to distributed information resources and electronic archives, to commercial and non-commercial information services in many countries. Its freely accessible archives contain information on almost all areas of knowledge and human activity - from new trends in science to weather forecasts.
Basic network technologies of LAN networks
Among them there are basic technologies on which the basis of any specific network. Examples include such well-known LAN technologies as Ethernet (1980), Token Ring (1985) and FDDI (late 80s).
At the end of the 90s. Ethernet technology has become the leader in LAN network technology, combining its classic version with up to 10 Mbit/s, as well as Fast Ethernet(up to 100 Mbit/s) and Gigabit Ethernet (up to 1000 Mbit/s). All Ethernet technologies have similar operating principles that simplify their maintenance and the integration of LAN networks built on their basis.
During the same period, their developers began to build network functions into the kernels of almost all computer operating systems that implement the above-mentioned network information technologies. Even specialized communication operating systems like IOS from Cisco Systems have appeared.
How GCS technologies developed
GKS technologies on analog telephone channels, due to the high level of distortion in them, were distinguished by complex algorithms for monitoring and data recovery. An example of them is the X.25 technology developed in the early 70s. XX century More modern network technologies are frame relay, ISDN, ATM.
ISDN is an acronym that stands for Integrated Services Digital Network and allows remote video conferencing. Remote access is ensured by installing ISDN adapters in PCs, which work many times faster than any modems. There is also special software that allows popular operating systems and browsers to work with ISDN. But the high cost of equipment and the need to lay special lines communication slows down the development of this technology.
WAN technologies have progressed along with telephone networks. After the appearance digital telephony special technology Plesiochronous Digital Hierarchy (PDH) was developed, supporting speeds of up to 140 Mbit/s and used by enterprises to create their own networks.
New Synchronous Digital Hierarchy (SDH) technology in the late 80s. XX century expanded throughput digital telephone channels up to 10 Gbit/s, and Dense Wave Division Multiplexing (DWDM) technology - up to hundreds of Gbit/s and even up to several Tbit/s.
Internet technologies
Network ones are based on the use of hypertext language (or HTML language) - a special markup language that is an ordered set of attributes (tags) that are pre-implemented by website developers into each of their pages. Of course, in this case we are not talking about text or graphic documents(photos, pictures) that have already been “downloaded” by the user from the Internet, are located in the memory of his PC and are viewed through text or It's about about so-called web pages viewed through browser programs.
Developers of Internet sites create them in HTML language (now many tools and technologies have been created for this work, collectively called “website layout”) in the form of a set of web pages, and site owners place them on Internet servers on a rental basis from the owners of their memory servers (the so-called “hosting”). They work on the Internet around the clock, servicing the requests of its users to view the web pages loaded on them.
Browsers on user PCs, having received access through the server of their Internet provider to a specific server, the address of which is contained in the name of the requested Internet site, gain access to this site. Further, by analyzing the HTML tags of each page being viewed, browsers form its image on the monitor screen in the way it was intended by the site developer - with all headings, font and background colors, various inserts in the form of photos, diagrams, pictures, etc.
Network information technologies represent a current and promising direction in the development of information technologies.
Their goal is not only to ensure the exchange of information between by individual users information and computing systems, but also the creation for them of the possibility of cooperative use of distributed information resources of society, obtaining reference, documentary and other information from various kinds of specialized information funds.
IN Lately The Internet became the central topic of publications not only in the computer press, but also in mass media, attracting the attention of information technology specialists, businessmen, ordinary users and the entire civilized world.
Date of birth of the global computer Internet networks It is generally accepted that the year is 1983. The real boom of the Internet came in the early 90s, when special navigation programs like Mosaic appeared, allowing owners of ordinary computers to surf the Internet using only one mouse. In fact, the Internet is not one computer network, but tens of thousands of local and global national networks connected to each other. The Internet is not a private company and does not even have its own president. The directions of Internet development are determined by the Internet Society, an organization headed by the Council of Elders, consisting of specialists working on a voluntary basis.
The Internet currently has over 40 million subscribers in more than 100 countries on all seven continents. The popularity of the Internet is evidenced by the fact that the number of network subscribers doubles every 10 months. The exchange of information via the network increases almost 10 times every year. Every second, over 4,000 electronic messages are transmitted over the network.
All Internet information technologies can be divided into systems information support and information exchange systems.
The rapid growth in the number of network users began after the emergence of a new service - WWW (World Wide Web) - a distributed hypertext system for accessing various information located around the world.
The worldwide computer network Internet is developing so rapidly that every year the number of its subscribers and the volume of information resources practically doubles. The tourism business is not left out of this boom either. Only in 1996, thousands of independent sections of travel agencies, hotels, airlines, and dozens of travel booking systems appeared on the Internet. Travel agencies should not ignore the Internet in their work. Moreover, the Internet cannot be considered only as a competitor in business; the network can provide invaluable information assistance and add to the traditional one a new channel for the sale of tourism services - electronic.
