Lesson summary on the topic of the Internet. Abstract of the lesson "global computer network". Problems of working on the Internet with Cyrillic texts
Lesson #10
Teacher Tashbaeva A.S. Subject: Informatics and ICT
Class: 11 Lesson date
Lesson topic: Organization and services Internet
The purpose of the lesson: Tutorials: contribute to the formation of concepts: The purpose of the communication services of the Internet. Purpose of information services of the Internet. Applied protocols. WWW basic concepts: web page, web server, web site, web browser, HTTP protocol, URL address. Search catalogue: organization, purpose. Search index: organization, purpose
Developing: develop students' understanding of the importance of systems thinking in modern science; develop the skill of quickly organizing the application of acquired knowledge in various situations. Apply Internet services in practical life.
Educational:
to form and develop students' cognitive interests;
fostering a sense of self-confidence and one's knowledge, a sense of responsibility for the results of one's work; develop teamwork skills.
Lesson type: Lesson learning new knowledge
Lesson resources: PC
During the classes
I. Organizational moment (3 min):
The teacher greets the students, checks their readiness for the lesson, informs the topic and purpose of the lesson.
Motivation for learning - the importance of this topic in modern society, give examples from life in the form of data structures: a census of people, a library-database of books, archives, etc.
II. Knowledge update (12 min): frontal student survey
History of the development of global networks
From the history of human society, you should know that many scientific discoveries and inventions have strongly influenced its course, the development of civilization. These include the invention of the steam engine, the discovery of electricity, the mastery of atomic energy, the invention of radio, etc. The processes of a sharp change in the nature of production, in everyday life, to which important scientific discoveries and inventions lead, are usually called the scientific and technological revolution.
The emergence and development of computer technology in the second half of the 20th century, they became the most important factor in the scientific and technological revolution.
There are three stages in this process.
First step began with the creation of the first computer in 1945. For about 30 years, a relatively small number of people used computers, mainly in the scientific and industrial fields.
Second phase began in the mid-70s of the XX century and is associated with the emergence and spread of personal computers (PCs). PCs have become widely used not only in science and production, but also in the education system, the service sector, and everyday life. PC entered the house as one of the species household appliances along with radios, televisions, tape recorders.
Third stage associated with the emergence of the global computer network Internet. As a result, a personal computer that fits on a desk has become a "window" into a vast world of information. New concepts have appeared, such as "world information space", "cyberspace". The spread of the Internet solves the important social problem of information inequality that exists between people living in different countries, on different continents, as well as in large cities and on the periphery. It is the development of the Internet that gives reason to say that the stage of the information society is coming in the history of civilization.
With the spread of computers,concept of computer literacy . This is the necessary level of knowledge and skills of a person, allowing him to use a computer for public and personal purposes.
At the first stage of computer development computer literacy was reduced to the ability to program. Programming was mainly studied in higher educational institutions, scientists, engineers, professional programmers owned it.
At the second stage Under the general level of computer literacy, they began to understand the ability to work on a personal computer with application programs, to perform the minimum necessary actions in the operating system environment. Computer literacy at this level is becoming a mass phenomenon due to learning at school, in numerous courses, in an independent mode.
On the third At the present stage, the ability to use the Internet has become an important element of computer literacy. A broader concept appeared - information culture. The number of computers connected to the global network is growing rapidly. And it becomes increasingly necessary to be able to use a computer to communicate with other people, for distance learning, searching for reference information, business activities and much more.
III. Stage of learning new knowledge (20 minutes)
Global network concept - systems of integrated computers located at large distances from each other - appeared in the process of development of computer networks. In 1964, a computerized early warning system for the approach of enemy missiles was created in the United States. The first non-military global network was the ARPANET in the United States, launched in 1969. It had a scientific purpose and united the computers of several universities in the country.
In the 80-90s of the last century, many branch, regional national computer networks were created in different countries. Their unification into an international network took place on the basis of the internetwork environment.
An important year in the history of the Internet was 1993, when the Internet service was created.World Wide Web (WWW) - World Information Network (World Wide Web). With the advent of the WWW, interest in the Internet has sharply increased, and the process of its rapid development and distribution has begun. Many people, when talking about the Internet, mean the WWW, although this is only one of its services.
The Internet is a complex hardware and software system which we have to deal with. We will try to get answers to three questions: what does the Internet consist of; How does it work; what it is used for. Often in literatureinstead of the word "Internet" use the term "Network" (respectfully capitalized). We also use it occasionally.
Internet hardware
Main components and any global networkare computer nodes and communication channels .
Here you can draw an analogy with the telephone network: the nodes of the telephone network are automatic telephone exchanges - automatic telephone exchanges, which are interconnected by communication lines and form a city telephone network. The phone of each subscriber is connected to a specific PBX.
To the knots Users' personal computers are connected to a computer network in the same way that subscribers' telephones are connected to telephone exchanges. Moreover, as a subscriber of a computer network, both an individual person through his PC, and the whole organization through his local network can act. In the latter case, a local network server is connected to the node.
An organization that provides data exchange services with a network environment is callednetwork service provider . The English word provider means "supplier", "supplier". The user enters into an agreement with the provider to connect to his node and subsequently pays him for the services provided (similar to how we pay for telephone network services).
Knot contains one or more powerful computers that are in a state of constant connection to the network. Information services are provided by the operation of server programs installed on host computers.
Each host computer has its own permanent Internet address; it's called an IP address .
An IP address consists of four decimal numbers, each in the range 0 to 255, separated by a dot . For example:
193.126.7.29
128.29.15.124
Network user computers receive the same IP addresses, but they are valid only while the user is connected to the network, i.e., they change in each new communication session, while the addresses of host computers remain unchanged.
Along with digital IP addresses operates on the Internetsymbolic address system more convenient and understandable for users. It is calleddomain name system (DNS - Domain Name System).
For example, the IP address 87.242.99.97 of the server of the methodological service of the BINOM. Knowledge Laboratory” corresponds to the domain name metodist.Lbz.ru. This name consists of three domains separated by dots.
The domain name system is built on a hierarchical basis . The first domain on the right (it is also called a suffix) is the top-level domain, the next one is the second-level domain, and so on. The last one (first on the left) is the computer name. Top-level domains are geographical (two-letter) or administrative (three-letter). For example, the Russian zone of the Internet owns the geographic domain ru. More examples: uk - UK domain; ca - domain of Canada; de - German domain; jp - Japanese domain. Administrative top-level domains most often belong to the American zone of the Internet: gov - the US government network; mil - military network; edu - educational network; com - commercial network.
Internet nodes have their own hierarchy . For example, a node in Samara has a connection to a node in Moscow, which in turn is connected to a number of nodes in the European backbone. The latter have a connection with the nodes of the USA, Japan, etc. And yet the structure of the Internet is not a tree, but a network. As a rule, each node has a connection not with one, but with many other nodes. Therefore, the routes along which information arrives at a certain node can be very different. This ensures the stability of the Network: when one node fails, information flows to other nodes are not interrupted. They can only change their routes.
Communication channels There are a variety of technical methods of communication in the global network:
telephone lines; electrical cable communication; fiber optic cable communication;
radio communication (via radio relay lines, communication satellites).
Different communication channels are differentthree main properties : throughput, noise immunity, cost .
In terms of cost, fiber optic lines are the most expensive, and telephone lines are the cheapest. However, with a decrease in price, the quality of the line also decreases: the throughput decreases, interference is more affected. Fiber optic lines are practically not subject to interference.
Bandwidth is the maximum rate at which information can be transmitted over a channel. It is usually expressed in kilobits per second (Kbps) or megabits per second (Mbps).
Throughput of telephone lines - tens and hundreds of Kbps; the throughput of fiber optic lines and radio communication lines is measured in tens and hundreds of Mbps.
For many years, most users of the Network connected to a node via dial-up (i.e., switchable) telephone lines. This connection is made using a special device calledmodem . The word "modem" is a combination of abbreviations of two words: "jodulator" - "dejodulator". The modem is installed both on the user's computer and on the host computer. The modem converts a discrete signal (issued by a computer) to a continuous (analogue) signal (used in telephony) and vice versa. The main characteristic of the modem is the maximum data transfer rate. In different models, it ranges from 1200 to 56,000 bps.
Cable communication is usually used over short distances (between different providers in the same city). For longer distances, it is more profitable to use radio communication. An increasing number of users in our time are moving from low-speed dial-up connections to high-speed unswitched communication lines.
Internet software
The operation of the Network is supported by certain software (SW). This software operates on servers and on personal computers of users. As you know from the computer science course of the basic school, the basis of all computer software is the operating system, which organizes the work of all other programs.Node computer software is very diverse . Conventionally, it can be divided intobasic (system) and applied . Basic software provides support for network operation over the protocolTCP/IP - the standard set of Internet protocols, i.e. it solves the problems of sending and receiving information.Application software is engaged in maintenance of various information services of the Network, which are commonly calledInternet services . The service combines servers and client programs that exchange data using some application protocols. Each service has its own server program: for e-mail, for teleconferencing, for the WWW, etc. The host computer acts as a server for a particular Internet service if it runs the server program for that service. The same computer can serve as a server for different services at different times; it all depends on what server-program is currently running on it. On the PC of network users, various information services are handled by client programs. Examples of popular clients are: Outlook Express - an e-mail client, Internet Explorer - a WWW service client (browser). When a user works with a certain Internet service, a connection is established between his client program and the corresponding server program on the host. Each of these programs performs its part of the work in providing this information service. This way the network works is calledclient-server technology .
How the Internet Works
Used on the Internetpacket communication technology . To better understand this, imagine the following situation. You need to send a multi-page document to a friend in another city (for example, a printout of a novel that you wrote). Your entire novel does not fit completely in an envelope, and you do not want to send it by parcel post - it will take too long. Then you divide the entire document into parts of 4 sheets, put each part in a mail envelope, write an address on each envelope and drop this entire pack of envelopes into the mailbox. For example, if your novel is 100 pages long, then you will have to send 25 envelopes. You can even drop the envelopes in different mailboxes at different communication centers (for fun, to see which will reach faster). But since the same address is indicated on them, all envelopes should reach your friend. And also, in order to make it convenient for a friend to assemble the whole novel, it is advisable to indicate serial numbers on the envelopes. Packet transmission of information on the Internet works similarly. The TCP / IP protocol, which was already mentioned earlier, is responsible for its work. It's time to figure out what these mysterious letters mean.
Packets are passed like relay sticks from one node to another. Moreover, the routes for different packets from the same message may be different. The described packet transmission mechanism is shown in Fig. 2.1. The issue of the route is decided separately for each packet. It all depends on where it is more profitable to transfer it at the time of processing. If a “break” occurs on some section of the Network, then the transmission of packets will bypass this section. at any given time, a lot of packets from a variety of messages move "mixed" over any network channel.
Document's name Computer_setu.doc
Abstract of a lesson in informatics with a presentation
Lesson topic: Computer networks. . Channels of connection.
Duration 45 minutes.
Class: 8
Lesson Objectives:
educational:
developing: formation and consolidation of skills of systematization and structuring of information; the formation of orientation skills in the information environment; to develop cognitive interest, speech and attention of schoolchildren, to form their information culture and the need to acquire knowledge; formation of general educational skills and abilities; expanding horizons; development of communicative qualities of a person; development of self-education skills using information and communication technologies;
educational
Lesson type
Equipment: computer, projector.
Software: Power Point presentation on the topic of the lesson
Lesson plan:
4. Test control - 5 min.
5. Homework - 2 min.
During the classes
1. Organizational part
Today in the lesson we will get acquainted with a new concept - a computer network, learn how, why and where the Internet appeared, learn about its capabilities. To successfully use the Internet, it is not necessary to know in detail how it works. Nevertheless, a general understanding of how the Internet works and the terms used will allow you to master the Internet much faster and avoid a large number of mistakes. Today, the doors to a new, virtual world will open for you, a world in which there are no borders and where everything is (in the virtual sense).
Showing slide 2
Question: What is the rate of information transfer; How far can you run a cable from one computer to another?
The students answer the teacher's question.
Features of such a connection:
Slow connection speed
Such networks are called local
Slide 3 is shown
line bus.
Slide 4 is shown
regional networks
corporate networks
Slide 5 is shown
Question
The students answer the teacher's question.
Slide 6 is shown
Question
Slide 7 is shown
(Students have prepared mini-reports
Slide 8 is shown
History of the creation of the Internet
The impetus for the creation of the Internet was the launch in the Soviet Union in 1957 of the first artificial satellite, in which the United States saw a threat to use missiles to launch a nuclear attack on the United States. In the same year, the Defense Advanced Research Project Agency (DARPA) was created under the US Department of Defense. The scientists were tasked with creating a computer network that could be used by the military during a nuclear attack on the country. The network was to be used to communicate between the command posts of the defense system.
Slide 8 is shown
Slide 9 is shown
It was for the ARPANet network that the IP protocol was created, which made it possible to divide files into packets and transfer them from node to node. Then the TCP protocol was created, which ensured the transfer of packets between the sending computer and the receiving computer, this protocol also made it possible to send lost packets. All these properties of the TCP protocol made it possible to use it for inter-network file exchange.
Show slide 10
October 29, 1969 is considered to be the birthday of the Network. On this day, the very first, though not entirely successful, attempt was made to remotely connect to a computer located at the Stanford University Research Center (SRI) from another computer, which was at the University of California, Los Angeles (UCLA). 500 km apart, SRI and UCLA became the first nodes of the future ARPANet network.
Then two more nodes were connected to them: the University of California Santa Barbara (UCSB) and the University of Utah (UTAH).
On display 11
Slide 12 is being shown
In 1972 was established public organization INWG is a working group on international networks led by Vincent Cerf. She coordinated the work to create the interworking capability. To combine networks operating over the IP protocol and networks operating over other protocols, it was necessary to create a special internetwork protocol. This protocol was created by Vincent Cerf and Robert Kahn in 1974 and named TCP.
After the two protocols TCP and IP were merged into one in 1982, the TCP / IP protocol became the standard protocol for the interconnected network - the Internet. In the same year, Cerf and his colleagues coined the term "Internet". Today is called the "Father of the Internet".
Russia first gained access to the Internet in the early 1980s. Access was provided by the Institute atomic energy them. I. V. Kurchatova. In 1990, RELCOM, a network of UNIX users, was created.
Slide 13 is being shown
Slide 14 is being shown
Slide 15 is being shown
Slide 16 is shown
according to the signal transmission method:
2. Telephone;
Slide 17 is shown
twisted pair
Slide 18 is being shown
Coaxial cable
Slide 19 is being shown
Fiber optic cable
Slide 20 is being shown
Slide 21 is shown
Wireless network
Slide 22 is shown
Satellite communication lines
Slides 23-27 are shown
Paul Baren
Joseph Licklider
Donald Davis
Vincent Cerf
3. In what year did TCP/IP become the standard protocol for the interconnected network - the Internet?
rnd.edu.runnet.ru
them. N.V. Sklifosovsky
them. I.V. Kurchatova
them. I.M. Sechenov
Slide 29 is shown
5. Homework:
Link
physical characteristics
Bandwidth
Noise immunity
Telephone communications
Radio communication
optical fiber
Satellite connection
6. Summing up the lesson.
What networks exist.
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Name: Bogdanova Larisa Mikhailovna
Position: computer science teacher
Place of work: Republic of Karelia MOUSOSH Nadvoitsy settlement
Republic of Karelia, town. Nadvoitsy, Segezhsky district
School website: nadvschool.narod.ru
‹ ›
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- Computer science
Description:
Lesson Objectives:
educational: to acquaint students with the main components of building the Internet: technical means, transmission technology; contribute to the formation of students in a holistic view of the work of the Internet, the interaction of hardware and software; mastering the basic concepts from the field of network technologies; mastering the main characteristics of information transmission using technical means;
developing: formation and consolidation of skills of systematization and structuring of information; formation of orientation skills in the information environment; develop cognitive interest, speech and attention of schoolchildren, form their information culture and the need to acquire knowledge; formation of general educational skills and abilities; expanding horizons; development of communicative qualities of a person; development of self-education skills using information and communication technologies;
educational: fostering interest in the subject being studied, fostering a positive attitude towards knowledge;
Lesson type: combined - explanation of new material with elements of the test.
Equipment: computer, projector.
Software: Power Point presentation on the topic of the lesson
Literature used in the preparation of the lesson:
1. Semakin I.G., Khenner E.K. Informatics: 10th grade. Moscow: Basic Knowledge Laboratory, 2005.
2. Internet from scratch! / Ed. ON. Domina. Moscow: Best Books, 2006.
3. Otarov S.K., Tarasenko M.N. Virtual space Internet. Rostov n/a: DSTU Publishing Center, 2000
4. Ugrinovich N. D. Informatics and information technology: Textbook for grades 10-11. Moscow: Basic Knowledge Laboratory, 2010.
5. Alferov A. P. Computer networks. Internet. M.: Informatics, 2005
6. Volchinskaya E.K. Information technologies and law. M.: Informatics, 2003
Lesson plan:
1. Organizational part - 1 min.
2. Reporting the topic and setting the objectives of the lesson - 2 min.
3. Presentation of new material - 30 min.
4. Test control - 5 min.
5. Homework - 2 min.
6. Summing up the lesson - 5 min.
During the classes
1. Organizational part2. Communication of the topic and setting the objectives of the lesson
Slide 1 is shown (Presentation)
Today in the lesson we will get acquainted with a new concept - a computer network, learn how, why and where the Internet appeared, learn about its capabilities. To successfully use the Internet, it is not necessary to know in detail how it works. Nevertheless, a general understanding of how the Internet works and the terms used will allow you to master the Internet much faster and avoid a large number of errors. Today, the doors to a new, virtual world will open for you, a world in which there are no borders and where there is everything (in the virtual sense).
3. Presentation of new material
Let's start with what we find out - why do we need computer networks. How do you think? The students answer the teacher's question.
When using computers, there is often a problem of transferring data from one computer to another. You can transfer data using external media. And if there are a lot of computers and they are located in different rooms of a 20-story building.
Showing slide 2
The easiest way to solve this problem is to connect computers to a network by connecting them through parallel or serial ports with a cable, and using special programs to ensure data transfer.
Question:
The students answer the teacher's question.
Features of such a connection:
- Slow connection speed
- Connection of computers is possible only within the same room
If you need to exchange data between computers located in different rooms, as we have at school or on different floors of the same building, then it is best to connect the computers to a network by connecting them using cables through special network adapters.
Such networks are called local. In this case, the speed of data exchange will be much higher.
And now let's play: You see pictures of computers on the board, suggest your version of the local network. Two people are invited to the board. We will see the advantages and disadvantages later.
Slide 3 is shown
The general scheme of connecting computers in a local network is called the network topology. Network topologies can be different. The option of connecting computers to each other, when a cable runs from one computer to another, connecting computers and peripherals in series with each other, is called line bus.
Slide 4 is shown
If each computer has a separate cable from one central node, then a local network of the "star" type is implemented. The advantage of a star-type local network is that if the network cable on one computer fails, the local network as a whole continues to function normally.
Now knowing about the topology of networks, let's compare what we got on the board with what we actually have. (Discussion in progress)
Local networks do not allow sharing access to users located in different parts of the city. They come to help regional networks, connecting computers within the same region (city, country, continent).
Many organizations interested in protecting information from unauthorized access (for example, military, banking, etc.) create their own, so-called corporate networks. A corporate network can unite thousands and tens of thousands of computers located in different countries and cities.
Slide 5 is shown
Large local networks, in turn, are combined into global networks. Global networks link computers within a country, continent, planet.
Question: How can computer networks be classified?
The students answer the teacher's question.
Slide 6 is shown
Thus, there are two types of networks: local and global.
Question: What features are common to all computer networks?
Slide 7 is shown
The purpose of all types of computer networks is determined by their two functions:
- Ensuring the sharing of hardware and software resources of the network
- Sharing Data Resources
(Students have prepared mini-reports and perform with them in front of classmates.)
Slide 8 is shown
History of the creation of the Internet
The impetus for the creation of the Internet was the launch in the Soviet Union in 1957 of the first artificial satellite, in which the United States saw a threat to use missiles to launch a nuclear attack on the United States. In the same year, the Defense Advanced Research Project Agency (DARPA) was created under the US Department of Defense. The scientists were tasked with creating a computer network that could be used by the military during a nuclear attack on the country. The network was to be used to communicate between the command posts of the defense system.
The main criterion for creating a network was the invulnerability of the network during a nuclear attack. The basic concept of the network is based on two main ideas:
- Lack of a central computer - all computers in the network are equal;
- Batch method of transferring files over the network.
Slide 8 is shown
This concept was proposed in 1962 by Paul Baren, who used the theory of batch file transfer, put forward by Leonard Kleinrock in 1961. The essence of P. Baren's idea is that the file that needs to be transmitted over the network is divided into several parts - packages. Each packet is transmitted independently of the others. At the end point on the computer, all packets are collected into a single file. Since the packets are transmitted independently, each packet can reach the destination computer along its own path.
Another theoretical source for the creation of the network was the concept of the "Galactic Network" by Joseph Licklider. According to this concept, with the help of the network, any person from anywhere on Earth can receive information and exchange files with any other person. Today we can say that this concept has been embodied in the modern Internet.
Slide 9 is shown
In 1962, within the framework of the ARPA, work began on computer projects. Joseph Licklider was appointed leader.
In 1966, the creation of a computer network was started. It was named ARPANet after the agency.
It was for the ARPANet network that the IP protocol was created, which made it possible to divide files into packets and transfer them from node to node. Then the TCP protocol was created, which ensured the transfer of packets between the sending computer and the receiving computer, this protocol also made it possible to send lost packets. All these properties of the TCP protocol made it possible to use it for inter-network file exchange.
Show slide 10
October 29, 1969 is considered to be the birthday of the Network. On this day, the very first, though not entirely successful, attempt was made to remotely connect to a computer located at the Stanford University Research Center (SRI) from another computer that was at the University of California, Los Angeles (UCLA). 500 km apart, SRI and UCLA became the first nodes of the future ARPANet network.
Then two more nodes were connected to them: the University of California Santa Barbara (UCSB) and the University of Utah (UTAH).
On display 11
It was these 4 organizations that distributed the main functions for creating components of the global network among themselves:
UCLA - carrying out measurement tests;
SRI - creation of an information center;
UCSB - development of mathematical apparatus;
UTAH - the first work on three-dimensional graphics.
Testing became possible due to the fact that by September 1, 1969, BBN manufactured the first copies of the IMP (Interface Message Processor) device, which provides communication between computers via telephone channels.
Slide 12 is shown
In 1972, the first International Conference on Computer Communications was held in Washington DC. The conference was attended by scientists from 10 countries. The conference participants were introduced to the ARPANet network.
In 1972, the public organization INWG, a working group on international networks, was created, under the leadership of Vincent Cerf. She coordinated the work to create the interworking capability. To combine networks operating over the IP protocol and networks operating over other protocols, it was necessary to create a special internetwork protocol. This protocol was created by Vincent Cerf and Robert Kahn in 1974 and named TCP.
After the merging of the two protocols TCP and IP into one in 1982, the TCP/IP protocol became the standard protocol for the interconnected network - the Internet. In the same year, Cerf and his colleagues coined the term "Internet". Today is called the "Father of the Internet".
Russia first gained access to the Internet in the early 1980s. Access was provided by the Institute of Atomic Energy. I. V. Kurchatova. In 1990, RELCOM, a network of UNIX users, was created.
March 20, 1998 is the first World Internet Day.
Teacher:
Slide 13 is shown
Today, the Internet is a combination of a large number of networks. Each network consists of tens and hundreds of servers. The servers are directly interconnected by various communication lines: cable, terrestrial radio communication, satellite radio communication. A large number of computers and local computer networks, which are network clients, are connected to each server. Clients can connect to the server not only through direct lines, but also through ordinary telephone channels. Communication channels are technical means that allow data to be transmitted over a distance. The main characteristics of communication channels are throughput and noise immunity.
Slide 14 is shown
Bandwidth - the maximum rate of information transfer over a communication channel (Kbps) without taking into account additional service information, such as start and stop bits, initial end block records, etc. Depends on physical properties communication channel.
Noise immunity sets the parameter of the level of distortion of the transmitted information. In order to avoid changing or losing information during its transmission, special methods are used to reduce the effect of noise.
Show slide 15
Computer communication channels can be classified as follows:
- by coding method: digital and analog;
- according to the method of communication: dedicated (permanent connection) and switched (temporary connection);
Slide 16 is shown
- according to the signal transmission method:
1. Cable: twisted pair, coaxial cables, fiber optic cables; optical (light guides), radio relay, wireless, satellite.
2. Telephone;
3.Radio: radio relay, satellite.
Slide 17 is shown
twisted pair consists of two insulated wires twisted together. Twisting wires reduces the influence of external electromagnetic fields on transmitted signals. The simplest version of a twisted pair cable is a telephone cable. The main disadvantage of twisted pair is poor noise immunity and low information transfer rate. Twisted pair cable according to the UTP-6 standard provides a transfer rate of up to 10Gb / s at a distance of up to 100m. Shielded twisted pair is used to improve noise immunity
Slide 18 is shown
Coaxial cable Compared to twisted pair, it has higher mechanical strength and noise immunity. For industrial use, two types of coaxial cables are available: thick and thin. A thick cable is more durable and transmits signals of the desired amplitude over a greater distance than a thin one. At the same time, thin cable is much cheaper.
Slide 19 is shown
Fiber optic cable- an ideal transmission medium, it is not affected by electromagnetic fields and has practically no radiation itself.
The use of a light signal ensures absolute independence from electromagnetic interference of natural origin and resulting from the operation of a wide variety of technical devices in production, transport, communication systems and at home, as well as the absence of electromagnetic radiation from the line. The advantage of fiber optics is undoubted: the information transfer rates realized in optical channels are still unattainable for copper cables.
Slide 20 is shown
Radio relay communication lines (RRL) designed to transmit signals in the ranges of decimeter, centimeter and millimeter waves. Transmission is carried out through a system of repeaters located at a distance of direct visibility. Repeaters receive the signal, amplify it, process it and transmit it to the next repeater. The total length of the RRL can reach thousands of kilometers. The disadvantages include: the limited range of one segment, which does not exceed 100 km, not only due to energy, but also due to the influence of the curvature of the earth on providing line of sight (an exception is TRL), the dependence of communication quality on the time of year and time of day.
Slide 21 is shown
Wireless network The equipment is intended for transmission of information (data, telephony, video, etc.) between computers, network and other specialized devices via radio channels. Recently, the idea of building a city core network with wireless access has become increasingly popular.
Slide 22 is shown
Satellite communication lines operate in 9 - 11 frequency bands and, in the future, in optical bands. In these systems, a signal from an earth station is sent to a satellite containing transceiver equipment, where it is amplified, processed and sent back to Earth, providing communication over long distances and covering large areas. There is a wide variety of satellite systems, both commercial and special purpose. The transmission speed in the satellite channel is up to 45 Mbps. Traditional satellite communication systems are constantly evolving, and the main trend of their development is to become cheaper. But the main barrier to using broadband satellite Internet access is the cost of dedicated broadband links: it's usually more efficient to use low bandwidth links.
Modern production requires high speeds of information processing, convenient forms of its storage and transmission. And therefore, for the development of communication channels on the Internet, it is necessary to improve the existing ones and look for new technologies.
4. Test control of mastering the material of the topic of the lesson.
If you don't have any questions, let's finish our lesson with a small test test. Good luck!
Slides 23-27 are shown
Text of the test paper
1. The creation of the ARPANet computer network was started:
- in 1975
- in 1966
- in 1945
- in 1980
2. The file that needs to be transferred over the network is divided into several parts - packets. Each packet is transmitted independently of the others. At the end point on the computer, all packets are collected into a single file. Since the packets are transmitted independently, each packet can reach the destination computer along its own path. Enter the name of the author of the idea.
- Paul Baren
- Joseph Licklider
- Donald Davis
- Vincent Cerf
3. In what year did TCP/IP become the standard protocol for the interconnected network - the Internet?
- 1975
- 1982
- 1984
- 1978
4. Specify the servers that belong to the domain zone of Russia:
- epson.au
- ntv.ru
- rnd.edu.runnet.ru
- school.ua
5. Which institution provided access to the Internet?
- them. N.V. Sklifosovsky
- them. I.V. Kurchatova
- them. I.M. Sechenov
(Mutual check in pairs, slide 28)
Slide 29 is shown
5. Homework: Find the main characteristics of communication channels and enter the data in the proposed table. Any sources can be used as sources of initial data.
6. Summing up the lesson.
Let's sum up the lesson. What have we learned today? The students answer the teacher's question. If there are no answers or they are not complete, then the teacher summarizes.
- Why and how computers are connected to a network.
- What networks exist.
- Who is called the "Father of the Internet".
- What is a network protocol and what is it for.
- Characteristics of communication channels and their classification.
This is not the end of our acquaintance with the Internet. We are waiting for new knowledge and discoveries!
Lesson topic: "Internet and the World Wide Web"
The purpose of the lesson : acquaintance with the global Internet and its information system - the World Wide Web (WWW), with ways to search for information in it.
Tasks:
to form the concepts of the Internet, the World Wide Web, a Web page and a Web site, to work out the skills of searching for information on the Internet; develop visual-figurative thinking, cognitive interest; educate information culture, safety rules for working on the Internet
During the classes
I . Organizing time
II . Formation of motivation
The topic of our lesson is "Internet and World Wide Web".
Today we will get acquainted with the global global network - the Internet, with the information system World Wide Web (WWW) - the World Wide Web; learn how to search for information in it.
III . Knowledge update
In the last lesson we talked about network hardware and software, let's repeat:
1) List the technical means of computer networks?
2) How are telephone lines used in computer networks?
3) What is a modem and what function does it perform?
IV . Explanation of new material
The Internet has firmly entered our lives. In modern society, it is impossible to imagine a single day without using the Internet. What is the Internet?
(students first formulate the definition on their own)
Internet
- worldwide global computer network.
The Internet combines thousands of local, industry, regional networks around the world.
Currently, more than 1 billion people use the Internet services.
Based on life experience, name the opportunities that the Internet provides.
What is the World Wide Web?
world wide web
- world wide web: distributed around the world Information system with hyperlinks, existing on the technical basis of the global Internet network.
The World Wide Web turned 27 years old in 2018.
Working with concepts in groups.
Web page
is a separate World Wide Web document.
web server - a computer on the Internet that stores Web pages and related software for working with them.
website
- a section of data on a Web server, physical or legal entity.
EachWeb page
has its own name, by which it can be found.
Independent work
Practical work No. 1 "Working with a search engine and website"
In the search bar of the Yandex or Google system, enter the name of your favorite music group
Determine what information the site offers about this group
Suggest what approximate sections the site should contain to fill it with the most important information
Practical work No. 2 "Working with e-mail"
Summing up the lesson
Questions to control:
Define the terms "Internet", "World Wide Web", "search engine", "site"
List the main ways to find information on the Internet?
VII.
Homework
Schematically develop a website with information about your favorite actor
» with the Internet and the World Wide Web topics
INTERNET AND THE WORLD WEB
Lesson topic: Internet and World Wide Web
The purpose of the lesson: To introduce students to the global Internet and its information system - the World Wide Web (WWW), with ways to search for information in it.
Tasks:
educational – to form the concepts of the Internet, the World Wide Web, a Web page and a Web site, the WWW hyperstructure, a Web browser; to instill the initial skills of searching for information on the Internet.
Educational - develop visual-figurative thinking, memory, attentiveness, cognitive interest.
Educational - education of information culture, a sense of pride in their school.
Program section:"Information transmission in computer networks".
Lesson type: a lesson in learning new material using IT technologies (computer presentation, Internet).
Type of lesson: combined.
Equipment: personal computers with high-speed Internet access, projector, presentation "Internet and the World Wide Web", cards with the text of practical work.
Literature: Semakin I. G. Informatics and ICT. Basic course: Textbook for grade 9. – M.: BINOM. Knowledge Lab, 2006.
Lesson plan
1) Organizational moment (greeting, report of the duty officer).
2) Motivational beginning of the lesson (setting the goal of the lesson).
3) Repetition. Updating knowledge (on questions).
4) Explanation of the topic of the lesson (using a presentation, the Internet).
5) Systematization and consolidation of theoretical knowledge (on issues).
6) Practical work "Searching for information on the World Wide Web" (work at a computer using high-speed Internet access).
7) Summing up, homework.
During the classes
Organizational moment (greeting, report of the duty officer).
Motivational start of the lesson
The topic of our lesson is “Internet and the World Wide Web”.
The purpose of the lesson: to get acquainted with the worldwide global network - the Internet; with a young, but very interesting service of this network - the information system World Wide Web (WWW) - the World Wide Web; with methods of information search in this system.
Knowledge update
Guys, you met with the hardware and software of networks in the last lesson. Let's remember.
1) What is included in the technical means of computer networks?
2) Why are telephone lines most often used as communication lines in computer networks?
3) What is a modem? What is its purpose in the network?
4) What value is the main characteristic of the modem? In what units is it measured?
5) What are the capabilities of the smart modem?
6) What is client-server technology?
Explanation of new material
Internet- worldwide global computer network.
The Internet combines thousands of local, industry, regional networks around the world.
An individual user who is not a subscriber of any of the listed networks can also connect to the Internet through the nearest hub.
Currently, more than 1 billion people use the Internet services.
The Internet provides users with a variety of services: e-mail, teleconferencing, file archives, Internet telephony, direct communication forums (chat).
The newest and most interesting service provided to users of the global network has recently become the ability to work with the World Wide Web (WWW) information system.
world wide web- World Wide Web: an information system distributed around the world with hyperlinks, existing on the technical basis of the global Internet network.
The World Wide Web is only 16 years old.
On this day, Tim Berners-Lee, who worked at the European Center for Nuclear Research in Geneva (Switzerland), published short description WWW project.
Web page- a separate World Wide Web document.
web server- a computer on the Internet that stores Web pages and related software for working with them.
website A section of data on a Web server owned by an organization or individual. In this section, its owner places his information in the form of many interconnected Web pages. Typically, a Web site has a main (home) page - Home page, from which you can move through the pages of the site using hyperlinks or forward-backward indicators.
Web page has its own name, by which it can be addressed.
Access protocol - http
Computer name - elhovka.narod.ru
Directory name - html
Filename - urok.htm
You don't have to surf the Web in a row, flipping through them like in a book.
The most important property of the WWW is the hypertext organization of links between Web pages.
These links operate not only between pages on the same server, but also between different WWW servers.
The transition from one page to another occurs through hyperlinks that form a network that resembles a web.
Usually hyperlinked keywords are highlighted or underlined on a Web page.
The role of a key for communication can be performed not only by text, but also by a picture, a photograph, a pointer to an audio document, so the term "hypermedia" is used instead of the term "hypertext".
Hypermedia- a system of hyperlinks between multimedia documents.
Web browser - special software that helps the user navigate the web. The most popular Web browser is Internet Explorer. The main task of the browser is to contact the Web server for the desired page and display the page on the screen.
Search required document WWW can happen:
by specifying the address of the document;
by moving along the "web" of hyperlinks;
through the use of search engines.
You can access the search server using a browser if you specify the server address. For example, http://www.yandex.ru
The user of the Internet during sessions of working on the network is immersed in the information space with unlimited resources.
Cyberspace is a set of world telecommunications systems and information circulating in them.
Systematization and consolidation of theoretical knowledge(on questions to §4 on p. 28)
Performing hands-on work on a PC"Searching for Information on the World Wide Web".
1. Find information about our village, which is posted on the school website, using all search methods:
1.1. Using the Web page address: http://elhovka.narod.ru/html/selo.htm
1.2. Using a hyperlink search from the home page of the school site: http://elhovka.narod.ru/index.htm
1.3. Using the Yandex search program (http://www.yandex.ru).
2. Using the search program Rambler (http://www.rambler.ru)
2.1. Find the site "Birds of Russia", which won in 2006 at the republican competition of research works in informatics (author Andrey Bogdanov).
2.2. Get acquainted with the list of birds living in our country.
3. Using the Google search program ( http://www.google.com)
3.1. Enter in the search box: the site "Informatics at school" and find the site "Informatics at school", which won the republican competition of research works in informatics in 2007 (author Andrey Bogdanov).
3.2. Learn about the evolution of computers.
4. Get acquainted with questions about the President and answers to them on the website of the President of Russia for citizens of school age http://www.uznay-prezidenta.ru
Summing up the lesson
1) What did you learn at the lesson today?
2) What is the Internet? The World Wide Web? Browser?
3) What are the ways to search for information on the Internet?
In the next lesson, we will take a closer look at the work of search servers, learn how to correctly form queries to search servers.
Abstract of the lesson in informatics.
Topic: “Global Internet.
Search for information on the Internet.
Class: Grade 11
The purpose of the lesson : to study the structure of the global Internet and master the basic methods of searching the network;
Tasks:
Educational: get acquainted with the concept of "Internet", study search engines and master the technology of information search in the global network;
Developing: formation of logical thinking techniques, development of interest in the subject, information culture, develop the ability to analyze and generalize, draw conclusions, broaden one's horizons;
Educational: education of accuracy, accuracy, independence, instilling the skills of group work, cooperation;
Health saving: compliance with sanitary standards when working with a computer, compliance with safety regulations, the optimal combination of forms and methods used in the lesson;
Advance preparation of students : material studied in previous computer science lessons;
Preliminary preparation of the teacher: studying the material of the lesson, writing a summary;
Didactic basics of the lesson :
Teaching methods: explanatory and illustrative, partially exploratory.
Lesson type: explanation of new material;
Forms academic work students: group, individual work.
Equipment: 11 computers, sheets of paper, markers, individual question cards, notebooks.
Lesson plan:
Org. moment (1-2 min.);
Explanation of new material (20 min.);
Independent work (15 min.);
The result of the lesson (3-5 minutes);
During the classes:
Lesson stages
Teacher activity
Student activities
Org. moment,
Reporting the topic of the lesson, its goals and objectives;
Brief plan of activity.
Hello guys!
So, the topic of today's lesson is: “The global Internet. Search for information".
Presentation for the lesson (Appendix 1).
In the lesson, we will get acquainted with the Internet, look at the global computer network Internet from different angles, get acquainted with search engines and learn how to search for the information we need (slide 1).
Write the topic of the lesson in a notebook.
Introduction to the topic:
Prepare children for the perception of the topic;
Aim for productive work.
The world has really changed with the advent of the global computer network Internet. Today, without leaving your home, you can meet and communicate with people who are far beyond the borders of your country, purchase various goods and services, and much, much more.
Pay attention to the following statistics. Here we can see how many people currently use the global Internet. And you will surely agree with me that the Internet has become an integral part of our lives (slide 2).
Let's try to find out what is the Internet?
You have been given a definition, but some words are missing from it. Try to restore these words yourself, and then we will write the correct definition in a notebook (2 minutes).
The Internet is ... ... a network that includes ..., ... and ... networks and connects millions ... around the world (slide 3).
Now let's try to highlight the strengths and weaknesses of the Internet.
Advantages
disadvantages
Important source of information
Internet information may be inaccurate
Communication with people from different cities
A person can go into the virtual world, invent an image for himself when communicating; addicted to the internet
Purchasing goods and services without leaving home
Fraud by the organization
Way to spread your knowledge
There are many viruses on the Internet that infect our computer.
Now you will be divided into 2 teams. The first group are Internet supporters, and the second group are opponents.
Within three minutes, you need to highlight the main advantages (for group 1) and disadvantages (for group 2) of the Internet.
Analysis, comparison, generalization and statement of own positions.
Team captains prepare a short (2 minutes) speech in which they substantiate the theses of their position.
Speech by the captain of the team of supporters.
Speech by the captain of the opposing team.
The speeches of the captains of the teams show the importance of the Internet in our days and set the rational use of it in order to avoid negative consequences.
Conclusion: We managed to look at the global computer network Internet from different angles. Both positive and negative qualities of it are revealed. Summarizing all of the above, we can conclude that the Internet is a very important source of information, which undoubtedly must be used, but one should not forget about the problems that a computer network carries..
Restore the definition, write it down in a notebook with the teacher.
They are divided into groups.
Group work.
Retrieve your positions.
Lesson topic:
Learn how to search for information on the Internet;
Consider Internet search engines.
And now we turn to the study of the topic. In the course of my story, you yourself write down the information you need (slides 5-6).
Working in the network, you need to quickly navigate the available amount of information.
There are basically three main types of information retrieval:
Indication of the page address; (slide 7)
This is the most fast way search, but it can only be used if you know exactly the address of the document or the site where the document is located.
This is the least convenient method, since it can be used to search for documents that are only similar in meaning to the current document.
Access to the search engine (slide 9).
Search server addresses are well known to everyone who works on the Internet. Currently, the following search servers are popular in the Russian-speaking part of the Internet: Yandex(yandex.ru), Google(google.ru) and Rambler(rambler.ru).
Search system provides the ability to search for information on the Internet.
Most search engines look for information on World Wide Web sites. (slide 10)
Guys, what search engines do you know? (yandex.ru, Rambler.ru, Google.ru and many others) (slides 11-12).
Yandex. en
Yandex is a Russian web search engine. The company's website, Yandex.ru, was launched on September 23, 1997.
Distinctive feature Yandex - the ability to fine-tune the search query. This is implemented through a flexible query language (slide 13).
Google. en
The leader of search engines on the Internet. According to one version, Google is a distorted spelling of the English word googol. "Googol (googol)" is a mathematical term denoting a unit with 100 zeros (slide 14).
Rambler. en
Rambler was founded in 1996.
The Rambler search engine understands and distinguishes between Russian, English and Ukrainian words. By default, the search is conducted by all forms of the word (slide 15).
The main things are written down in a notebook (on their own !!!)
Fixing the material
And now there will be work in pairs. You sit down at computers. You will be given cards on which problematic questions are written. You need to find different points of view on this issue on the Internet, and write down on the cards the url addresses and search engines in which you found the answer to the question posed (Appendix 2).
Individual work on computers.
Summing up the lesson:
systematization of knowledge gained in the lesson
What is a global computer network?
What is a search engine?
What search engines do you know (recognized)?
Evaluation of children for practical work.
Used Books:
1. Gein A.G., Senokosov A.I. Informatics and ICT (basic and specialized levels). - M .: Education, 2009
2. Ugrinovich N.D. Informatics and information technologies. Textbook for grades 10-11 / N.D. Ugrinovich. - 4th ed. – M.: BINOM. Knowledge Laboratory, 2007. - 511 p.: ill.
