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6.6.
History of the Internet and the World Wide Web
The Internet is a communication system and at the same time an information system an environment for people to communicate.
Currently, there are many definitions of this concept.
In our opinion, one of the definitions of the Internet that most fully characterizes the information interaction of the world's population is: "The Internet is a complex transport and information system of mushroom shaped (dipole) structures, the cap of each of which (actually dipoles) represents the brain of a person sitting at a computer, together with the computer itself, which is like an artificial extension of the brain, and the legs, for example, a telephone network connecting computers, or the ether through which radio waves are transmitted."
The emergence of the Internet has given impetus to the development of new information technologies that lead not only to a change in the consciousness of people, but also of the world as a whole.
However, the World Wide Web was not the first discovery of this kind.
Today, the Internet is developing in the same way as its predecessors the telegraph, telephone and radio.
However, unlike them, it combined their advantages – it became not only useful for communication between people, but also a publicly accessible means for obtaining and exchanging information.
It should be added that the possibilities of not only stationary, but also mobile television have already been fully used on the Internet.
The history of the Internet begins around the 60 years of the XX century.
The first documentary description of the social interaction that will become possible thanks to the network was a series of notes written by J. Licklider.
In these notes, the concept of the "Galactic Network" was discussed.
The author foresaw the creation of a global network of interconnected computers, through which everyone can quickly access data and programs located on any computer.
In spirit, this concept is very close to the current state of the Internet.
In July 1961, Leonard Kleinrock published the first article on the theory of packet switching.
In the article, he presented the advantages of his theory over the existing principle of data transmission – channel switching.
What is the difference between these concepts?
When switching packets, there is no physical connection between the two terminal devices (computers).
In this case, the data required for transmission is divided into parts.
Each part is accompanied by a header containing full information about the delivery of the package to its destination.
When switching channels for the time of information transmission, two computers are physically connected "each to each".
During the connection period, the entire amount of information is transmitted.
This connection is maintained until the end of the information transfer, i.e., just as it was when transmitting information over analog systems that provide connection switching.
At the same time, the utilization rate of the information channel is minimal.
To test the concept of packet circuit switching, Lawrence Roberts and Thomas Merrill in 1965 connected a TX 2 computer in Massachusetts to a Q 32 computer in California using low speed telephone dial up lines.
Thus, the first (albeit small) non local computer network in history was created.
The result of the experiment was the understanding that time separated computers can successfully work together by executing programs and fetching data on a remote machine.
It also became clear that a telephone system with switching channels (connections) is absolutely unsuitable for building a computer network.
In 1969, the American agency ARPA (Agency for Advanced Research Projects) began research on the creation of an experimental network "with packet switching".
This network was created and received the name ARPANET, i.e. the network of the Agency for advanced research projects.
A sketch of the ARANET network consisting of four nodes – the embryo of the Internet is shown in Fig. 6.1 [21].
Figure 6.1
At this early stage, research was conducted on both network infrastructure and network applications.
At the same time, work was underway to create a functionally complete protocol for intercomputer interaction and other network software.
In December 1970, the Network Working Group (NWG) under the leadership of S. Crocker completed work on the first version of the protocol, called the Network Control Protocol (NCP).
After the implementation of NCP on ARPANET nodes was completed in 1971 – 1972, network users were finally able to start developing applications.
In 1972, the first application appeared – e mail.
In March 1972, Ray Tomlinson wrote basic programs for sending and reading electronic messages.
In July of the same year, Roberts added to these programs the ability to issue a list of messages, selectively read, save to a file, forward and prepare a response.
Since then, email has become the largest network application.
For its time, e mail has become what the World Wide Web is today – an exceptionally powerful catalyst for the growth of the exchange of all types of interpersonal data flows.
In 1974, the Internet Network Working Group (INWG) introduced a universal protocol for data transmission and networking – TCP/IP.
This protocol is used in the modern Internet.
However, the transition of ARPANET from the NCP protocol to TCP/IP took place only on January 1, 1983.
It was a "Day X" - style transition, requiring simultaneous changes on all computers.
The transition was carefully planned by all interested parties over the previous few years and went surprisingly smoothly (however, it led to the spread of the "I survived the transition to TCP/IP" icon).
In 1983, the transfer of ARPANET from NCP to TCP/IP made it possible to divide this network into MILNET, the actual network for military needs, and ARPANET, used for research purposes.
In the same year, another important event took place.
Paul Mockapetris has developed a domain Name System (DNS).
This system allowed us to create a scalable distributed mechanism for displaying hierarchical computer names (for example, www.acm.org) in Internet addresses.
In the same year, 1983, a Domain Name Server (DNS) was created at the University of Wisconsin.
This server (DNS) automatically and secretly from the user provides the translation of the dictionary equivalent of the site to the IP address.
With the general spread of the Network outside the United States, national first level domains ru, uk, ua, etc. appeared.
In 1985, the National Science Foundation (NSF) took part in the creation of its own NSFNet network, which was soon connected to the Internet.
Initially, the NSF consisted of 5 supercomputer centers, however, less than in APRANET, and the data transfer rate in communication channels did not exceed 56 kbit / s.
At the same time, the creation of NSFNet was a significant contribution to the development of the Internet, as it allowed us to take a new look at how the Internet can be used.
The Foundation set a task for every scientist and engineer in the United States to be "connected" to a single network, and therefore began to create a network with faster channels that would unite numerous regional and local networks.
Based on the ARPANET technology, the NSFNET network (the National Science Foundation NETwork) was created in 1986, in the creation of which NASA and the Ministry of Energy were directly involved.
Six large research centers equipped with the latest supercomputers, located in different regions of the United States, were connected.
The main purpose of this network was to provide US research centers with access to supercomputers, based on a reference interregional network.
The network operated at a base speed of 56 Kbit/s.
When creating the network, it became obvious that it is not even worth trying to connect all universities and research organizations directly to the centers, since it is not only very expensive to lay such a large amount of cable, but it is almost impossible.
Therefore, we decided to create networks on a regional basis.
In each part of the country, interested institutions were connected with their nearest neighbors.
The resulting chains were connected to the supercomputer centers through one of their nodes, so the supercomputer centers were connected together.
With this design, any computer could communicate with any other, transmitting messages through neighbors [29].
One of the problems that existed at that time was that early networks (including ARPANET) were built purposefully in the interests of a narrow circle of interested organizations.
They were supposed to be used by a closed community of specialists; as a rule, the work of networks was limited to this.
There was no special need for network compatibility, respectively, there was no compatibility itself.
At the same time, alternative technologies began to appear in the commercial sector, such as XNS from Xerox, DECnet, as well as SNA from IBM.
Therefore, under the auspices of DARPA NSFNET, together with specialists from the subordinate thematic groups on Internet Technology and Architecture (Internet Engineering and Architecture Task Forces) and members of the NSF Network Technical Advisory Group, "Requirements for Internet Gateways"were developed.
These requirements are formally gar the compatibility of the parts of the Internet managed by DARPA and NSF was checked.
In addition to choosing TCP/IP as the basis of NSFNet, US federal agencies have adopted and implemented a number of additional principles and rules that have formed the modern look of the Internet.
What is very important, NSFNET pursued a policy of "universal and equal access to the Internet".
In fact, in order for an American university to receive funds from the NSF for an Internet connection, it, as it was written in the NSFNet program, "must ensure that this connection is available to all trained users on campus" [29].
NSFNET initially worked quite successfully.
But the time came when she stopped coping with the increased needs.
The network created for the use of supercomputers allowed connected organizations to use a lot of information data that was not related to supercomputers.
Netizens in research centers, universities, schools, etc.realized that they now have access to a lot of information and that they have direct access to their colleagues.
The flow of messages on the Network grew faster and faster, until, eventually, it overloaded the computers that control the network and the telephone lines connecting them.
In 1987, NSF handed over to Merit Network Inc. a contract under which Merit, with the participation of IBM and MCI, was to provide management of the NSFNET reference network, make the transition to higher speed T 1 channels and continue its development.
The growing support network already combined more than 10 nodes.
In 1990, the concepts of ARPANET, NFSNET, MILNET, etc. they finally left the scene, giving way to the concept of the Internet.
The scope of the NSFNET network, combined with the quality of the protocols, led to the fact that by 1990, when ARPANET was finally dismantled, the TCP/IP family had displaced or significantly displaced most other protocols of global computer networks around the world, and IP was confidently becoming the dominant data transportation service in the global information infrastructure.
In 1990, the European Organization for Nuclear Research (European Organization for Nuclear Research) organized the largest Internet site in Europe and provided access to the Internet of the Old World.
To assist in the promotion and promotion of the concept of distributed computing via the Internet CERN (Switzerland, Geneva) Tim Berners Lee has developed a hypertext document technology the World Wide Web (WWW), which allows users to have access to any information located on the Internet on computers around the world.
The WWW technology is based on: the definition of URL specifications (Universal Resource Locator, universal resource pointer), HTTP (HyperText Transfer Protocol, hypertext Transfer Protocol) and the HTML language itself (HyperText Markup Language, hypertext markup language).
The text can be marked up in HTML using any text editor.
A page marked up in HTML is often called a Web page.
To view a Web page, a client application is used – a Web browser.
In 1994, the W3C Consortium was formed, which brought together scientists from various universities and companies (including Netscape and Microsoft).
Since that time, the committee has been dealing with all the standards in the Internet world.
The first step of the organization was the development of the HTML 2.0 specification.
In this version, it became possible to transfer information from the user's computer to the server using forms.
The next step was the HTML 3 project, work on which began in 1995.For the first time, the CSS system (Cascading Style Sheets, hierarchical style sheets) was introduced.
CSS allows you to format the text without violating the logical and structural markup.
The HTML 3 standard was never approved, instead HTML 3.2 was created and adopted in January 1997.
Already in December 1997, the W3C adopted the HTML 4.0 standard, which is divided into logical and visual tags.
By 1995, the growth rate of the Internet showed that the regulation of connectivity and financing issues could not be in the hands of the NSF alone.
In 1995, the payment for connecting numerous private networks to the national highway was transferred to regional networks.
The Internet has grown far beyond what it was seen and designed, it has outgrown the agencies and organizations that created it, they could no longer play a dominant role in its growth.
Today it is a powerful worldwide communication network based on distributed switching elements - hubs and communication channels.
Since 1983, the Internet has been growing exponentially, and hardly a single detail has been preserved since that time – the Internet still operates on the basis of a set of TCP/IP protocols.
If the term "Internet" was originally used to describe a network built on the basis of the Internet Protocol IP, now this word has acquired a global meaning and is only sometimes used as the name of a set of integrated networks.
Strictly speaking, the Internet is any set of physically separate networks that are connected to each other by a single IP protocol, which allows us to talk about them as one logical network.
The rapid growth of the Internet caused an increased interest in TCP/IP protocols, as a result, specialists and companies appeared who found a number of other applications for it.
This protocol began to be used for building local area networks (LAN - Local Area Network) even when their connection to the Internet was not provided.
In addition, TCP/IP has been used to create corporate networks that have adopted Internet technologies, including the WWW – World Wide Web) - the World Wide Web, in order to establish an effective exchange of internal corporate information.
These corporate networks are called "Intranet" and can either connect or not to the Internet.
The inventor of the World Wide Web is Tim Berners Lee, who is the author of HTTP, URI/URL and HTML technologies [69].
In 1980, for his own needs, he wrote the program "Enquirer" ("Interrogator"), which used random associations to store data and laid the conceptual basis for the World Wide Web.
In 1989, Tim Berners Lee proposed a global hypertext project, now known as the World Wide Web.
The project involved the publication of hypertext documents linked by hyperlinks, which would facilitate the search and consolidation of information for scientists.
To implement the project, he invented URI identifiers, the HTTP protocol and the HTML language.
These are technologies without which it is impossible to imagine the modern Internet.
Between 1991 and 1993, Berners Lee improved the technical specifications of these standards and published them.
He wrote the world's first web server "httpd" and the world's first hypertext web browser, called "WorldWideWeb".
This browser was also a WYSIWYG editor (sok.
What You See Is What You Get), its development was started in October 1990, and completed in December of the same year.
The program worked in the "NeXTSTEP" environment and began to spread over the Internet in the summer of 1991.
Berners Lee created the world's first web site at http://info.cern.ch/, the site is now stored in the archive.
This site appeared online on the Internet on August 6, 1991.
This site described what the World Wide Web is, how to install a Web server, how to use a browser, etc.
This site was also the first Internet directory in the world, because later Tim Berners Lee posted and maintained a list of links to other sites there.
Since 1994, the World Wide Web Consortium (W3C), founded by Tim Berners Lee, has taken over the main work on the development of the World Wide Web.
This Consortium is an organization that develops and implements technological standards for the Internet and the World Wide Web.
The W3C's mission is "To fully unlock the potential of the World Wide Web by creating protocols and principles that guarantee the long term development of the Network."
The other two most important tasks of the Consortium are to ensure the complete "internationalization of the Network" and make the Network accessible to people with disabilities.
The W3C develops uniform principles and standards for the Internet (called" Recommendations", English W3C Recommendations), which are then implemented by software and hardware manufacturers.
Thus, compatibility between software products and hardware of various companies is achieved, which makes the Worldwide Network more perfect, universal and convenient.
All Recommendations of the World Wide Web Consortium are open, that is, they are not protected by patents and can be implemented by anyone without any financial contributions to the consortium.
Currently, the World Wide Web is formed by millions of Internet Web servers located around the world.
A web server is a program that runs on a computer connected to the network and uses the HTTP protocol for data transmission.
In its simplest form, such a program receives an HTTP request for a certain resource over the network, finds the corresponding file on the local hard disk and sends it over the network to the requesting computer.
More complex Web servers are able to dynamically allocate resources in response to an HTTP request.
To identify resources (often files or parts of them) the World Wide Web uses uniform resource identifiers URI (English Uniform Resource Identifier).
Uniform URL Resource locators are used to determine the location of resources in the network.
Such URL locators combine URI identification technology and the domain Name System DNS (English Domain Name System) – the domain name (or directly the IP address in a numeric record) is part of the URL to designate a computer (more precisely, one of its network interfaces) that executes the code of the desired Web server [29].
To view the information received from the Web server, a special program is used on the client computer –a Web browser.
The main function of a Web browser is to display hypertext.
The World Wide Web is inextricably linked with the concepts of hypertext and hyperlinks.
Most of the information on the Web is hypertext.
To facilitate the creation, storage and display of hypertext on the World Wide Web, the HTML language (English HyperText Markup Language), the hypertext markup language, is traditionally used.
The work on hypertext markup is called layout, markup masters are called webmasters.
After HTML markup, the resulting hypertext is placed in a file, such an HTML file is the most common resource of the World Wide Web.
After the HTML file becomes available to the web server, it is called a "web page".
A set of web pages forms a website.
Hyperlinks are added to the hypertext of web pages.
Hyperlinks help users of the World Wide Web to easily navigate between resources (files), regardless of whether the resources are located on a local computer or on a remote server.
Hyperlinks of the "web" are based on URL technology.
In general, we can conclude that the World Wide Web stands on "three pillars": HTTP, HTML and URL.
Although recently HTML has begun to lose its position somewhat and give way to more modern markup technologies: XHTML and XML.
XML (eXtensible Markup Language) is positioned as a foundation for other markup languages.
To improve the visual perception of the web, CSS technology has become widely used, which allows you to set uniform design styles for many web pages.
Another innovation that is worth paying attention to is the URN resource designation system (English Uniform Resource Name).
A popular concept of the development of the World Wide Web is the creation of a semantic web.
The semantic web is an add on to the existing World Wide Web, which is designed to make the information posted on the network more understandable for computers.
A semantic web is a concept of a network in which every resource in a human language would be provided with a description that is understandable to a computer.
The semantic web provides access to clearly structured information for any application, regardless of the platform and regardless of programming languages.
Programs will be able to find the necessary resources themselves, process information, classify data, identify logical connections, draw conclusions and even make decisions based on these conclusions.
With wide distribution and competent implementation, the semantic web can cause a revolution on the Internet.
To create a computer understandable description of a resource in the semantic web, the RDF format (English Resource Description Framework) is used, which is based on XML syntax and uses URI identifiers to designate resources.
Novelties in this area are RDFS (English RDF Schema) and SPARQL (English Protocol And RDF Query Language) (pronounced "sparkle"), a new query language for quick access to RDF data.
Currently, there are two trends in the development of the World Wide Web: the semantic web and the social web.
The semantic web involves improving the connectivity and relevance of information on the World Wide Web through the introduction of new metadata formats.
The social web relies on the work of organizing the information available in the Web, performed by the users of the Web themselves.
In the second direction, the developments that are part of the semantic web are actively used as tools (RSS and other web feed formats, OPML, XHTML microformats).
Internet telephony has become one of the most modern and economical types of communication.
Her birthday can be considered February 15, 1995, when VocalTec released its first soft phone a program that serves for voice exchange over the IP network.
Then Microsoft released the first version of NetMeeting in October 1996.
And already in 1997, it became quite common to connect two ordinary telephone subscribers via the Internet, located in completely different places on the planet.
Why is regular long distance and international telephone communication so expensive?
This is explained by the fact that during a conversation, the subscriber occupies an entire communication channel, not only when talking or listening to the interlocutor, but also when he is silent or distracted from the conversation.
This is what happens when voice is transmitted over the phone in the usual analog way.
With the digital method, information can be transmitted not continuously, but in separate "packets".
Then it is possible to send information from many subscribers simultaneously via one communication channel.
This principle of packet transmission of information is similar to the transportation of many letters with different addresses in one mail car.
After all, they donot" drive " one mail car to transport each letter separately!
Such a temporary "batch compaction" allows you to use existing communication channels much more efficiently, "compress" them.
At one end of the communication channel, the information is divided into packets, each of which, like a letter, is provided with its own individual address.
The packets of many subscribers are transmitted "interspersed"over the communication channel.
At the other end of the communication channel, packets with the same address are combined again and sent to their destination.
Such a batch principle is widely used on the Internet [29].
Having a personal computer, a sound card, a microphone and headphones (or sound speakers) compatible with it, the subscriber can use Internet telephony to call any subscriber who has a regular landline phone.
During this conversation, he will also pay only for using the Internet.
Before using Internet telephony, the subscriber the owner of a personal computer must install a special program on it.
It is not necessary to have a personal computer to use Internet telephony services.
To do this, it is enough to have a regular phone with a tone dial.
In this case, each dialed digit goes into the line not in the form of a different number of electrical pulses, as when the disk rotates, but in the form of alternating currents of different frequencies.
This tone mode is available in most modern telephones.
To use Internet telephony using a telephone device, you need to buy a credit card, and call a powerful central computer server at the number indicated on the card.
Then the server's automatic voice machine (optionally in Russian or English) informs the commands: dial the serial number and key of the card using the buttons of the telephone, dial the country code and the number of your future interlocutor.
Next, the server turns the analog signal into a digital one, sends it to another city, to a server located there, which again converts the digital signal into an analog one and sends it to the desired subscriber.
The interlocutors talk as if on a regular phone, although sometimes there is a small (for a fraction of a second) delay in answering.
Recall that to save communication channels, voice information is transmitted in" packets " of digital data: your voice information is divided into segments, packets called Internet Protocols (IP).
In 2003, the Skype program was created (www.skype.com), completely free and does not require almost any knowledge from the user either to install it or to use it.
It allows you to talk in video mode with interlocutors who are at their computers in different parts of the world.
In order for the interlocutors to see each other, the computer of each of them must be equipped with a web camera.
This is such a long way in the development of communication tools that humanity has done: from signal fires and drums to a cellular mobile phone, which allows two people to contact almost instantly, located anywhere on our planet.
At the same time, despite the different distances, subscribers have a feeling of personal communication.
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