The Internet refers to the means of computer telecommunications.

Telecommunication (in a broad sense) is communication between subjects (people, devices, computers) located at such a distance from each other that it excludes direct contact (“tele” - remote, “communication” - connection, message). In this sense, telecommunications include: the exchange of light signals between ships at sea, other methods of visual and sound communication (for example, drum mail among African tribes), telegraph, telephone, television.

Development computer telecommunications started long before the Internet (in its current form) and long before Windows. For example, in the 80s, public BBS (bulletin board system) file servers operating in the MS-DOS environment appeared all over the world (including in the USSR). BBS subscribers were able to view (and leave) advertisements for free, exchange email messages and files, participate in discussions, etc. The non-profit network FIDOnet became popular in Russia, uniting students, teachers, engineers and, in general, all computer technology enthusiasts. In parallel, other forms of long-distance communication developed - Telnet, FTP, etc. (see below).

Internet connection

Hardware Requirements
for working with the Internet

V. Web camera(preferably).

I. Communication equipment:

Modem(speed not lower than 33.6 Kbps; compliance with V.34 (for 33.6 Kbps modems) and V.90 (for 56 Kbps) standards) or LAN card

II. Link:

Dial-up telephone line(preferably via digital PBX) or Dedicated communication channel(directly to the provider or through a LAN - local area network).

III. Video system(video card and monitor):

Min. configuration: VRAM 2Mb/14” Advanced configuration: VRAM 32Mb/17”

IV. Sound card + audio system(speakers or headphones, preferably a microphone).

The standard device by which your computer can be connected to the world wide web is modem (MO duulator- DEM odulator) is a small electronic device built into a PC or located in a separate case. The modem connects to the computer and to a regular telephone socket. The only function of the modem is to convert discrete ( digital) the signal your PC is working with is continuous ( analog) a signal transmitted over a telephone line (and vice versa).
Special software is used to work with the modem. As a communication channel between your computer and a node on the Network, either a regular (switched, i.e. switched) or a specially dedicated telephone line can be used.
We will be looking mainly at telecommunications software. Telecommunications software is divided into two classes: server programs And client programs. Server programs are located on a remote computer on the Internet and process user requests. Often a computer with server programs is also called a “server”. However, you should remember that several server programs can run on one server computer. Client programs reside on your computer and send their requests to the server program.

Internet architecture

Internet network (from the user’s point of view) is a collection of large nodes interconnected by communication channels. Each node is one or more powerful server computers (or host computers(from the English “host” - owner)). A node (or subnetwork of nodes) is managed by its owner - an organization called provider(from the English “provide” - to provide) or an Internet service provider. In many cases, the name of an individual network is the name of its provider. Providers, for a fee, serve both collective (LAN) and individual Internet users, providing them with a certain set of services.

The most famous providers in Russia: GlasNet, Relcom, Demos, Sovarn Teleport, Russia-OnLine, Sprint-Russia and many others.

Largest foreign providers: CompuServe and America-OnLine.

Protocols

Protocol is a set of agreements on the rules for the formation and formats of Internet messages, on methods of exchanging information between network subscribers.

Distinguish two main types of protocols Internet:

basic protocols, responsible for the physical transfer of electronic messages of any type between Internet computers - TCP (Transmission Control Protocol) and IP (Internet Protocol). These protocols are so closely related to each other that they are most often referred to as “TCP/IP protocol”;

application protocols higher level, responsible for the functioning of specialized Internet services: protocol HTTP(transmission of hypertext messages), protocol FTP(file transfer), email protocols, etc.

Application protocols are located “above” the basic protocols: a-priory your computer cannot work on the Internet unless it has TCP/IP support installed. However, some application protocols may be missing on your computer.

Addresses

Each computer connected to the Internet has a unique physical address (IP address) , made up of four decimal numbers, each in the range from 0 to 255 (four bytes). These numbers are written separated by a dot, for example:
193.126.7.29
128.29.15.124.
However, it is inconvenient for a person to use such an address. Therefore, on the Internet it is customary to assign each physical address symbolic (domain) address , which is made up of meaningful letter symbols (segments) separated by a dot, for example:
www.glasnet.ru
www.microsoft.com
ftp.elvis.ru, etc.

The domain address is read by the order of elements from right to left ( Fig.1).

Rice. 1 Relationship between the concepts of segment, domain and domain name

Segments– domain name components separated by dots.
Domain– a set of computers that have the same sequence of segments on the right side of their domain name.
Senior domain(top-level domain) indicates either the country in which the host is located or the type of organization that owns the host (some top-level domains are described in the table below).

Second level domain denotes a node (provider); Sometimes minor domains appear in a domain name, pointing to the subnets of a given host (for example, ames.arc.nasa.gov).
Junior domain symbolic address is the name of the computer or server of this node.
To assign and convert symbolic addresses into computer-readable physical addresses, a special service has been created on the Internet called DNS (Domain Name System– system for naming computers on the Internet).

Internet services

Telnet. This term refers to the protocol and network program that serves remote access client to the server computer. After establishing a connection, the user finds himself in the operating system environment of the remote computer and can use not only its information resources, but also run programs (both stand-alone and client-server types).

FTP. This is the name of the protocol (File Transfer Protocol) and programs that work with directories and files on a remote machine. FTP tools allow you to browse server directories and files, move from one directory to another, copy and update files.

Gopher is a protocol and programs that provide more advanced (compared to FTP) means of searching and retrieving information using multi-level menus, reference books, index links, etc. The Gopher protocol is supported in modern navigator programs. Just like WWW servers, Gopher servers contain links to each other, and to work with information resources it is absolutely not necessary to know their specific location. Gopher servers are searched by a special search program called Veronica. For the most part, the files contained on these servers are academic documents and large text files. To learn more about Gopher, you can visit gopher://veronica.scs.unr.edu/11/veronica.

Archie. This is the name of special servers (Archie servers) that collect and store search information about the content of FTP servers on Internet sites. If you are looking for a file whose name (or part of it) you know, you need to launch the Archie client, and it will show you the address(es) of the corresponding FTP server.

WAIS. Wide Area Information Servers is a distributed information system (databases and software) that serves information retrieval in network databases and libraries. In particular, WAIS is used to index and search unstructured documents on the Internet.

Email. This is the English designation Email– the main type of Internet network services. With the help of email, people living on all continents exchange electronic messages and files.

Usenet. There are several definitions Usenet systems– distributed discussion club, teleconferences, news groups. Unlike e-mail, a Usenet client sends a message not to an individual recipient, but to a group of subscribers (teleconferences). All participants in this conference have equal rights when discussing a particular issue. Each teleconference has its own address and is dedicated to a topic (science, art, sports, recreation, etc.), and the range of issues discussed can be very diverse - from very broad (“about everything”) to very narrow (for example, culinary recipes).

IRC. A type of teleconference can be considered IRC (Internet Relay Chat) - “chat” in real time. With the help of IRC servers and IRC clients, users conduct a “virtual” conversation among themselves, typing phrases from a PC keyboard.

Internet telephony. Nowadays, a new type of Internet service is rapidly developing – Internet telephony. The principle of voice communication on the Internet cannot be considered original: such communication is only a special case of the exchange of arbitrary electronic messages via the TCP/IP protocol. Human speech is converted into digital file(in the same way that audio files are created) and transmitted over the Internet in the form of a regular set of electronic packets.

WWW (World Wide Web - “World Wide Web”)– interactive hypertext information retrieval system on the Internet. Data blocks WWW (Web pages) are located on separate computers called WWW servers(or Web servers) and owned by individual organizations or individuals. Using hypertext links embedded in WWW documents, the user can navigate from one document to another.

WWW Terminology

The WWW is based on the Hypertext Messaging Protocol HTTP (HyperText Transfer Protocol), and the pages themselves are formatted using a special hypertext document description language HTML (HyperText Markup Language).
To work with WWW, special client programs are used, which in English are called browsers(from the verb “browse” - to view), and in Russian - Internet browsers, browsers, browsers, navigators. In our country, the most popular browsers today are Microsoft Internet Explorer and Netscape Navigator from Netscape.
Web page is a World Wide Web document that contains text and (or) graphic, audio, video information, as well as links to other Internet documents (not necessarily Web pages).
Physically, a Web page is most often a file formatted using the HTML language, with the extension .htm or .html. Graphic objects in Web pages are most often files in .gif and .jpg formats.
Hypertext is a document that, along with ordinary text and graphic information, contains links to other documents, and these links are built into text fragments or graphic objects of this document. Since the role of a link can be played not only by text, but also by multimedia information (graphics, sound, video), the concept of “hypertext” is considered to be an extension of the concept “hypermedia”.
An example of hypertext documents is the help pages of Windows applications - these “pages” are organized in much the same way as Internet pages: links are underlined or highlighted in color, and the mouse pointer, when placed over a link, takes the shape of a hand with the index finger extended ( rice. 2). An invisible document address in URL format is embedded in the link of a Web page. To go to the document to which the link points, just click on it with the left mouse button.

Through the use of various network protocols, the Internet can provide two main functions:

· be a means of communication between remote users;

· be a means of access to shared information resources located on the Internet.

Obviously, each of these functions can be implemented through different means, resulting in a variety of services provided to Internet users. The means of providing certain services for users of the global network are usually called Internet services. At the same time, communication services provide communication between remote users, and information services enable users to access certain information resources stored on the Internet.

Communication Services

Obviously, there can be only two modes of communication on the network: the mode of direct communication in real time, when users are connected to each other during communication. An analogue of such communication is talking on the phone. Sometimes the term on-line is used to refer to this mode. Another mode is the delayed communication mode (off-line). An example of such communication in everyday life is sending a letter or telegram.

Direct communication on the Internet

Direct communication forums - IRC (Internet Relay Chat)

This system allows Internet and Intranet users to chat in real time. To receive this service, users must join channels that support different discussion topics. Any characters entered through the IRC program appear on the screens of all other participants in your channel. The technology for using IRC has much in common with working in Usenet conferences. But if communication there takes place in deferred mode, then a live conversation can take place here. The peculiarity of this communication is that the text of the message is entered using the keyboard and then appears on the general display. Thus, when using this service, communication between participants occurs on-line in written form. Similar to teleconferences, chat conference participants are divided into thematic groups.

Currently communication in " chat“is used as a kind of game in which each participant usually comes up with some kind of “image” for himself and plays it out. It is not customary for chat participants to engage in real communication. However, the chat service can also be used for serious communication - both collective and personal. One of the popular programs that provides operation in this mode is ICQ. In November 1996, the first version of ICQ (I seek you, i.e. “I'm Looking for You”) was launched on the Internet and has since spread like an avalanche. It can be downloaded for free from the website: http://www.mirabilis.com. After installing the program, it will automatically download when you connect to the Internet.

Internet telephony

This service provides the opportunity for voice communication via the Internet in on-line mode. This is a new, developing service. Its main advantage over the telephone is its low price. The quality of Internet telephony is still inferior to telephone communication (time delays, sound distortion), but over time these shortcomings are gradually being overcome.

The general operating principle of IP telephony telephone servers is as follows: on the one hand, the server is connected to telephone lines and can connect to any telephone in the world. On the other hand, the server is connected to the Internet and can communicate with any computer in the world. The server receives a standard telephone signal, digitizes it (if it is not originally digital), compresses it, splits it into packets and sends it over the Internet to its destination using the Internet Protocol (TCP/IP). For packets coming from the Network to the telephone server and going into the telephone line, the operation occurs in the reverse order.

IP telephony technology combines circuit-switched networks (transmitting voice information) and packet-switched networks (transmitting data) into a single communication network. Seamless voice recognition and transmission from one network to another is solved using various gateways. As shown in Fig. 1, a gateway is a device that includes telephone lines on one side and an IP network on the other.

Rice. 1. Scheme of operation of IP telephony

Voice, like analog vibrations in an IP telephony system, exists only in the handset. In the remaining sections of the transmission channel from subscriber to subscriber, speech is digitized and transmitted in the form of IP packets. Packets arriving at the gateway closest to the other subscriber are converted back into analog form (voice signal) and are sent to the telephone line. The most widely used program in practice is Skype (pronounced "skype") - a free program that provides encrypted voice communication over the Internet between computers (VoIP), as well as paid services for communicating with subscribers of a regular telephone network. You can download the program from the website at http://www.skype.com/intl/ru/home.

Telnet service

This service provides interaction with a remote computer. It allows you to turn the user's computer into a remote terminal of another computer. Therefore, this service is also called e remote terminal simulation. A terminal differs from a regular computer in that it does not perform its own calculations. Everything that is entered on the workstation keyboard is transmitted to the remote computer, and the resulting results are transmitted back and displayed on the workstation monitor. The remote computers are mainly machines running the UNIX operating system. Therefore, working in remote terminal mode requires knowledge of the basic commands of this operating system. With the development of graphical operating systems such as Windows, command mode has become less popular, and Telnet service Recently, most users do not use it. Many information systems previously available exclusively through Telnet, today are available from the World Wide Web, which will be discussed below.

Having established a connection using Telnet, the user gets the opportunity to work with the remote computer as if it were “his own”, i.e. theoretically have all resources at your disposal if access to them is allowed. Really Telnet provides open access, but the organization of interaction is completely determined by the remote computer. Two types of Internet services require connection to servers via Telnet: library catalogs and electronic bulletin boards (BBS).

Work with a remote system can be carried out in a “transparent” mode, when programs on the server and the client only provide the connection protocol, and in a command mode, when the client receives a set of server commands at its disposal. It should be noted that for security reasons there is a tendency to reduce the number of Internet nodes that allow the use of Telnet to connect to them.

Delayed communication on the Internet

Email - Email

This is the oldest and one of the most popular services on the Internet. Its purpose is to support the exchange of emails between users. At its essence, e-mail is a system for exchanging electronic messages in computer networks (in delayed communication mode - offline). The email operation diagram is shown in Fig. 2. A mail server is a kind of post office that receives incoming and outgoing correspondence from users registered on it. This correspondence is placed in users' "mailboxes" - specially designated sections on the hard drive. Each user receives a personal mailing address at which letters will be sent to him. It should be noted that email addresses are somewhat different from other Internet addresses, but very similar. They consist of two parts, separated by the @ symbol. To the right of the symbol is the Internet address of the computer on which the subscriber's post office is located. This address is formed in the same way as any other domain name on the Internet. To the left of the @ symbol is the subscriber's name. An example of a postal address would be: [email protected].

Rice. 2. Email operation scheme

In order for this service to become available to the user, a number of procedures must be completed. First, the user must register on the mail server. In this case, the client's email address and password are recorded - a set of characters that allows the user to be identified. The presence of a password ensures the confidentiality of this service. A registered user has the opportunity to write the text of the letter, indicating the recipient's address. For this purpose, a letter preparation editor is included in the email client program. Prepared letters are placed in the Outbox folder. The server receives all letters from the Outbox folder and, in addition, transmits received letters, which are placed in the Inbox folder. The user's connection to the mail server is necessary only for sending letters and delivering letters from the inbox to the user's computer. The mail server is constantly running. It periodically looks through “mailboxes” and organizes the transmission of outgoing letters over the network. The mail server arranges incoming correspondence into “boxes”.

In addition to the function of receiving and transmitting letters during a communication session, the email client program can perform many more service functions:

· preparation and editing of letters,

· organization of address book,

· viewing the mail archive,

· sorting and deleting letters from the mail archive, etc.

A popular E-mail client is Outlook Express, which comes standard with the MS Windows operating system.

The email server and client operate using different protocols. The POP3 (Post Office Protocol) server program, among other things, performs the function of protecting information. During a communication session, it establishes the user’s identity and provides communication with his personal mailbox. When operating the client program, no identification is required. Its task is to transmit outgoing letters to the server and receive incoming ones. It uses the simpler SMTP protocol (Simple Mail Transfer Protocol).

Teleconferencing service

A teleconference is a system for exchanging electronic messages on a specific topic between network subscribers (in delayed communication mode - offline). Each participant receives all materials to his or her email address (E:mail). Each subscriber's e-mail is published on the teleconference server and reaches all participants. (Fig.3).

Rice. 3. Teleconference operation scheme

Unlike e-mail, when a user sends his letter personally to a subscriber or group of subscribers, in teleconferences the letter is sent simultaneously to all its participants. In turn, all messages that arrive at the conference will be sent to the user's mailbox and downloaded to his computer during the communication session. To participate in the teleconference, you must subscribe to it. There are specific addresses for these purposes. Each conference is devoted to a specific topic, so correspondence in it occurs only within the framework of the topic. According to some estimates, the number of ongoing online conferences has exceeded 50,000.

The newsgroup service is called by many names: newsgroups, Usenet service. At Network nodes, news servers service teleconferences. A news client program must be installed on the user's PC. The MS Outlook Express program mentioned above is both an email client and a news client.

Teleconferences combine both communication and information functions. On the one hand, personal communication takes place here, on the other hand, the conference materials contain a large amount of useful information, which is stored on the server for a certain period of time. This information can be considered as some kind of information resource (electronic newspaper). This is especially important for specialists participating in conferences on professional topics: science, production, business, trade, etc. In the conference materials you can find valuable advice and consultations that will help in making important decisions.

Information services

Information services provide users with the ability to access certain information resources stored on the Internet. Such resources are either files in one of the generally accepted formats or various documents. The use of these resources is provided through the corresponding services.

File Transfer Service

This service is often referred to by the name of the protocol it uses: FTP (File Transfer Protocol). On the Network side, the service is provided by so-called FTP servers, and on the user side by FTP clients. The purpose of an FTP server is to store a set of files for a wide variety of purposes (usually in archived form). Most often these are program files: system and application software. But sets can store files of any other formats: graphic, audio, MS Word, MS Excel documents, etc. All this information forms a hierarchical structure of folders (directories and subdirectories).

After connecting the FTP client to the server, a file interface for storing folders and files on the server opens on the user’s screen (similar to Windows Explorer). Further work occurs in the same way as with the file system on a PC: folders and files can be viewed, sorted, and copied to your own disks. The FTP client is included in Internet Explorer and is therefore always available on a PC running MS Windows.

File sharing

A file hosting service is a service that provides the user with a place to store his files and 24/7 access to them via the web, usually via the http protocol (and possibly via FTP). This service allows you to conveniently “exchange” files.

On the central page of the file hosting service, the user uploads a file to the file hosting server, and the file hosting service gives the user a permanent link, which he can send by e-mail, publish on blogs, forums, or send via instant messaging systems (ICQ, MailAgent, IM, etc. .).

World Wide Web (WWW)

WWW is a distributed information system with hyperconnections that exists on the technical basis of the worldwide computer network Internet. This information system is a network of documents interconnected by hyperlinks. Such documents are called hypertext. Since links can point to any document located on the Internet anywhere in the world, this system is called the World Wide Web.

Smallest information unit WWW is Web- a page that is a collection of text, graphic and multimedia files linked by hyperlinks. Group Web pages belonging to the same owner and related to each other in content, constitute Web site. Host - a computer designed to store Web pages And Web- sites are called Web server. Client - a program designed to view Web sites, called a browser (from English browse - view, scroll through).

Browser(from the English Web browser; browser option - outdated form) - software for viewing websites, that is, for requesting web pages (mainly from the Internet), processing them, displaying them and moving from one page to another.

Most browsers can also display a table of contents for FTP servers.

Browsers have constantly evolved since the birth of the World Wide Web and, with its growth, have become increasingly popular programs. Nowadays, a browser is a complex application for processing and displaying various components of a web page and for providing an interface between a website and its visitor. Almost all popular browsers are distributed free of charge or “bundled” with other applications: Internet Explorer (shared with Microsoft Windows), Mozilla Firefox (free, open source software, compatible with some Linux distributions, such as Ubuntu), Safari (shared with Mac OS X and free for Microsoft Windows) Google Chrome(free), Opera (free since version 8.50).

Electronic media

Electronic media (media) are a convenient means of obtaining current information. Almost all modern newspapers, magazines, radio stations, television channels (Russian and foreign) have their own websites on the Internet, where you can read the news, listen to and watch information messages (including in real time). On the website www.karta-smi.ru you can find links to Russian electronic media.

The electronic version of the newspaper allows you not only to read the latest issue, write and send a review of what you read to the editor, but also to gain access to a file of old issues of the newspaper. On the websites of TV channels you can watch news programs and TV shows, participate in on-line conferences and forums, discuss what you see, and express your opinion. On the websites of radio stations you can listen to news programs and radio broadcasts on-line.

Comprehensive Internet Services

The introduction of the Internet into practical activities has led to the emergence of new services that combine both communication and information capabilities of the global network. These include:

On-line translators and dictionaries

Using on-line translators and dictionaries on the Internet, you can translate texts from Russian into English and vice versa.

This way you can translate email texts, website content, etc.

Online stores

In online stores you can choose a wide variety of products, place an order, and the selected products will be delivered to your home. This way you can purchase, for example, educational and fiction CDs. As a rule, such purchases are cheaper than in regular stores.

Electronic payment systems

Electronic payment systems allow you to pay for a wide range of services, in particular, make utility payments. The scheme by which electronic payment systems work is extremely simple for the user. By registering in the system, you automatically open your account. Having credited the required amount of money to it in a way convenient for you, you can use it for settlements with partners of this system.

The most widespread payment systems in Russia are:

· Qiwi, currency - Russian rubles

· Yandex.Money, currency - Russian rubles

· WebMoney, currency - Russian rubles, euros, US dollars, hryvnias, etc.

These systems are easy to use. For example, to safely and quickly pay for goods and housing and communal services on the Internet, you can use the Yandex system. Money. To do this, you need to go to the Yandex.Money website or money.yandex.ru, register and create an electronic account.

A server, or server software, is a computer program or device that provides functionality to other programs or devices, called "clients."

The following types of servers are distinguished:

Proxy server

A proxy server is an intermediary between a client program (usually a web browser plays this role) and an external server (another server on the Internet), filters requests, improves performance and connection quality. The client connects to the proxy server, requesting some services such as a file, connection, web page from another resource - the server interprets and forwards the request.

Types of servers Mail server

Mail servers transmit mail client data through local and global corporate networks, as well as over the Internet. Provide messaging and data storage.

Server platforms

The term is often used synonymously with operating system. The server platform is the underlying hardware or software for the system and acts as the “engine” that drives the server.

Web server

The web server serves to exchange data between the user's web browser and the network via the http protocol. Performs a number of the following functions: automates the operation of web pages, keeps a log of access to network resources, is responsible for authentication and authorization of users, supports https to ensure a secure connection.

Applications server

The application server is conventionally called middleware, since the server data takes up a significant part of the computing territory between the database servers and end users.

FTP server

One of the oldest Internet services, File Transfer Protocol allows you to securely move one or more files between computers while maintaining file security, privacy, and control over data transfers.

Collaboration Server

Software designed to enable users to collaborate regardless of their location, over the Internet or a corporate intranet.

Virtual server

In 2009, the number of virtual servers exceeded the number of physical servers. Today, server virtualization has become commonplace in the data processing industry.

Telnet Server

A Telnet server allows users to connect to remote machines and perform tasks on a remote computer.

Open Source servers

Server open source operating system. It supports common email protocols (IMAP, SMTP and POP3) and can be easily integrated with many existing webmail systems. The server has flexible anti-spam protection and provides anti-virus protection for all incoming and outgoing email. Open source software is an important part of many IT infrastructures.

| Planning lessons for the school year (textbook for Federal State Educational Standards by L.L. Bosov, A.Yu. Bosov) | §4.4 Website creation technologies. Contents and structure of the site. Website design. Website placement on the Internet

Lessons 29 - 31
§4.4 Website creation technologies. Content and structure of the site
Website design. Website placement on the Internet

Keywords:

Site structure
navigation
website design
website page template
hosting

4.4.1. Website creation technologies

There are several ways to create websites.

Firstly, a website can be created using the hypertext markup language HTML (Hyper Text Markup Language). In this case, in a text editor (for example, Notepad), the text that you want to place on the pages of the site is marked with special marks called tags. Tags contain instructions about how the text should look. To distinguish tags from text, they are enclosed in angle brackets (Figure 4.7).

Secondly, you can save a document prepared in a word processor (Microsoft Word, OpenOffice Writer) as a web page (in HTML format).

Third, you can use special software - visual HTML editors or website builders.

A web designer is a specialist who designs the structure of a website, as well as selecting methods for presenting information and performing the artistic design of a web project. A web designer must know modern web technologies; It is desirable that he have an artistic education.

Rice. 4.7. The simplest web page and its HTML code

You can try to master the basics of web design on your own by taking the distance learning course “Web Design” by A. A. Duvanov at the University of Robotic (http://www.botik.ru/~robot/ru/).

Regardless of what tools you use to create a website, you should first think about its content and structure.

Let's say you attend a computer graphics club and decide to create a website for this creative association. The content of the site should be such as to reflect the creative life of the members of the association and attract the attention of like-minded people.

Now it is necessary determine the structure (plan) of the site

Obviously, the site may include general information (program and schedule of classes, location of classes, last name, first name, patronymic of the leader, etc.), a page of news and announcements, personal pages of the leader and members of the association, a gallery of works by members of the association, useful links to other Internet resources and much more. Let's depict the structure of the site in the form of a graph (Fig. 4.8).

Rice. 4.8. Hierarchical structure of the site

Representing the site structure in the form of a graph provides a visual representation of the site content and helps organize navigation - transitions from one website page to another.

4.4.3. Website design

Any site loads from the main (home) page (home page), which first of all should answer the question “What is this site about?” To do this, the main page contains the name of the site, a thematic graphic image, short text describing the content of the site, as well as the main menu - links to the main sections of the site. Also on the main page can be placed the name of the site author and his contact information, visitor counter, news, etc.

Each page of the site, as a rule, has several permanent elements that are always located in the same places. This:

The site title, located at the very top of the page;
the main menu, usually located on the left side of the page (the number of menu items, their names and order are the same on all pages of the site).

It is desirable that the site pages be made in the same style. To maintain the style, it is easier to first develop a site page template on which to present the elements found on all pages of the site (Fig. 4.9).

Rice. 4.9. Sample website page template

When filling the pages of the site with information materials, you should adhere to the following recommendations:

Do not put a period in the names of the site and pages if they consist of one sentence.
Keep menu item names short; It is unacceptable to stretch the title of an item over several lines.
Do not choose a colorful background for pages; against such a background the text will be difficult to read.
Do not place too many information and artistic blocks on the page.
Don't write too long texts. Break the text into small paragraphs, separating them from each other with blank lines.
Use the same formatting techniques in each paragraph.

4.4.4. Website placement on the Internet

Before posting a site on the Internet, you should test it, i.e., make sure that it is displayed correctly in different browsers: texts are readable against the selected background, pictures are in the right place, hyperlinks provide correct transitions, etc.

Hosting is a service for placing a website on a server that is constantly located on the Internet; hosting can be either paid or free.

Large companies usually use paid hosting to host their websites. At the same time, they receive a second-level domain name that is easy to read and remember, which can coincide with the company name.

Individuals can use free hosting for their websites, the capabilities of which are limited compared to paid options (small disk space, limit on the size of an individual file, only a third-level domain name, etc.), but they are quite sufficient for user home pages and non-commercial sites. The main disadvantage of free hosting is that when hosting your site, the company independently adds commercial advertising to its pages.

A list of servers that provide free hosting can be obtained by searching for “free hosting”.

THE MOST IMPORTANT

Site structure (plan)- dividing the general content into semantic sections and separate pages, indicating the connections between them.

Representing the site structure in the form of a graph provides a visual representation of the site content and helps organize navigation - transitions from one page of the site to another.

Page template- This is a page diagram that shows the elements found on the pages of the site. Using page templates helps maintain a consistent website design style.

Hosting- service for hosting a website on a server that is constantly located on the Internet; hosting can be either paid or free.

Questions and tasks

1. Read the presentation materials for the paragraph contained in the electronic appendix to the textbook. Does the presentation complement the information contained in the text of the paragraph?

2. What tools can you use to create websites?

3. What is the site structure?

4. Think over and graph the structure of one of the following sites:

a) “Our class”;
b) “My family”;
c) “Informatics”.

5. List the main elements placed on the site pages.

7. What is the purpose of website testing?

8. What is the main disadvantage of free hosting?

9. Name an Internet server known to you that provides users with free website hosting.

Have you ever wondered where the main Internet server, alpha, is located? Or, who is the master of the Internet? Now, probably, most readers will laugh and say that the Internet cannot have any owner, since the Internet is simply an association of many computers and other network devices.

Simple, but not entirely simple. In a sense, the Internet has masters. After all, this whole association of computers is not just a shapeless anthill; in fact, the Internet has a rigid hierarchical structure, the presence of which allows you to easily communicate with computers located on the other side of the globe. Who are these “owners”? How is it that the Internet does its job? What needs to be done to paralyze the Internet? Today's article is devoted to these topics.

One of the most important organizations on the Internet is IANA - Internet Assigned Numbers Authority - “Internet Address Space Administration”. This non-profit American organization distributes IP addresses. Your Internet connection is made through one of the IP addresses of your subnet, the so-called gateway. And if this gateway receives data from the local network from an address that does not fall into the subnet described on the gateway, it will simply ignore such a packet.

Domain names

But the matter does not end with IP addresses - even if the Internet functions perfectly and packets reach the target IP addresses, we must not forget that we almost always use not IP addresses when wanting to get to a site, but normal names type site, and the conversion of such names into IP addresses is handled by DNS services

If the DNS server of an Internet visitor does not know how to resolve a domain name (for example, a website), then he will turn not to anyone, but to the domain server responsible for the ua zone. Where will he get his address if he doesn’t know it in advance? And to do this, he will turn to one of 13 so-called root DNS servers. But their addresses are already permanent and registered in all operating systems.

These root domain servers are managed by ICANN - Internet Corporation for Assigned Names and Numbers. This, again, non-profit American organization maintains the uninterrupted operation of 13 root servers, and also distributes those responsible for top-level domain zones - ua, ru, com and others. Each country has its own organization responsible for the corresponding top-level zone. And this organization already determines the procedure for distributing domain names in its country.

What needs to be done to disrupt the Internet so that DNS names stop resolving into IP addresses? To do this, disrupt the functioning of the root DNS servers. The Internet will not “disappear” immediately, of course, but problems will begin immediately. Attempts to attack these servers are constantly being made. You can also attack a specific top-level domain zone.

Google has gotten involved in storing information about domain names. Although it does not distribute domain names, it stores information about all available ones. Google's DNS address is very easy to remember: 8.8.8.8 and 8.8.4.4.

It is extremely important to host your website on high-quality and fault-tolerant hosting.