Computer networks. Classification of computer networks. ……………4

Fast Ethernet network. …………………………………………………………..5

network topology. ……………………………………………………...….eight

Ensuring the safety of work in the Computing Center. ……….12

Computer networks. Classification of computer networks.

According to the principles of construction, computer networks are divided into local and remote (Fig. 1).

Local networks are created, as a rule, in one organization or in one room.

The simplest variant of such a network is the connection of computers through parallel or serial ports. In this case, there is no need for any additional equipment. There should be only connecting conductors. Such a connection between computers is configured within the same room. It is used to transfer data from one computer to another. In this case, you can transfer data without the help of floppy disks. Any modern operating system shell has software that provide such data transfer.

In local peer-to-peer computer networks, computers are connected to the network through special network adapters, and the network operation is supported by the network operating system. Examples of such operating systems are: Novell Personal Net Ware, Net Ware Line, Windows for Workgroups.

All computers and their operating systems in local peer-to-peer computer networks must be of the same type. Users of this network can transfer data to each other, use shared printers, magnetic and optical disks, etc.

In a local multi-rank computer network, one more powerful computer is used, which is called a server, and other less powerful computers are called workstations. Servers use a special system software, which is different from the system software of workstations.

Remote computer networks are divided into regional and international. Regional ones are created in certain regions, for example, a state, and international ones provide a connection between your computer and another computer on the World Wide Web. An example of such networks is Relcom (for the CIS countries) and Internet (for the whole world). In principle, it is possible to access the Internet from regional computer networks.

The connection of computers in regional networks is provided by conventional telephone networks or networks specially allocated for this purpose through special devices called modems. The modem converts binary code signals to language range audio signals and vice versa.

Computers of a certain area (city) are connected via modems and communication lines to a more powerful computer, which is called a provider. More than 100 providers are currently operating in Ukraine.

Each computer user that is connected to the network is assigned details (address). Providers, using requisites, ensure the connection of the corresponding computers of users.

Communication between computers on different continents is carried out by satellite communication channels.

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Introduction

The development of economic and social relations, the expansion of the network and enterprises and the increase in their size, the emergence of new ties between enterprises and industries, the increase in the flow and volume of information - all this has led to a sharp complication of managerial tasks.

The complication of the tasks solved in the field of management, in turn, led to a change in the nature of management processes. The use of computers significantly increases the efficiency of management, but it assumes the active participation of a person in the management process. It is he who makes the final decision on the basis of an assessment of various calculation options, taking into account the additional data at his disposal.

Industrial and technological practice is an organic part of the educational process and has the goal of consolidating and deepening the knowledge gained in the process of theoretical activity, to introduce the student to socially useful work and to link the received theoretical knowledge with real conditions production. During the passage of industrial technological practice, student interns work according to the regime established for this enterprise and obey the internal regulations of this organization.

The purpose of the production and technological practice is to study by students a real enterprise and working conditions on it, to acquire applied skills in developing and maintaining programs, studying information flows and workflow, ways of storing and processing information, collecting materials for a report and preliminary selection of a probable topic for a graduation project. In addition, during the internship, student interns must also take an active part in the social life of the enterprise.

1. Production activity of the enterprise

Municipal state-financed organization culture "Vozhegodsk regional cultural and leisure association"

Year of creation - 01.11.2007. The network of MBUK "VR KDO" consists of 14 branches: Houses of culture and clubs. Director of MBUK "VR KDO" Lyubov Alexandrovna Klyushina. The main goal of the work of MBUK "VR KDO": Creation of conditions for organizing leisure and providing residents of the district with the services of cultural and leisure institutions.

To achieve this goal, the following tasks were set for 2012:

Improving the organization of work to improve the skills of KDO specialists using new methods.

Creation of conditions for increasing the efficiency and effectiveness of the work of the KFOR.

Work to form a positive image of the BWW institutions.

Priority areas of work of MBUK "VR KDO":

Patriotic and spiritual and moral education of citizens.

Promotion of family values.

Preservation and revival of traditional folk culture.

Prevention of a healthy lifestyle.

Cultural and entertainment activities.

Formation and development of cultural brands of settlements.

Inter-settlement festivals and holidays are held annually.

Performance indicators of MBUK "VR KDO" in 2012:

4586 events were held, including 2389 screenings.

Conducted 3748 events on a paid basis, including 2389 film screenings.

54923 visitors were served, 13788 of them were at film screenings.

32,001 paid visitors were served, of which 13,788 were at film screenings.

There were 135 club formations with 993 members.

All Houses of Culture and clubs carry out their activities in accordance with the goals and objectives.

2. IS architecture, software tools, methods of processing and storing information, organization of the database, familiarization with the network structure and composition of the VT

The institution "Vozhegodsk Regional Cultural and Leisure Association" uses the topology of the "Zvezda" network, that is, two computers are connected to each other using a router.

The star topology is the basic topology of a computer network in which all computers on the network are connected to a central node (usually a switch), forming a physical network segment. Such a network segment can function both separately and as part of a complex network. network topology(usually "tree"). The entire exchange of information goes exclusively through the central computer, which in this way has a very large load, so it cannot do anything other than the network. As a rule, it is the central computer that is the most powerful, and it is on it that all the functions of managing the exchange are assigned. In principle, no conflicts in a network with a star topology are possible, because the management is completely centralized, what the star topology looks like can be seen in diagram No. 1.

Scheme No. 1.

Characteristics of institutional computers

"Vozhegodsk regional cultural and leisure association":

Specifications:

Computer #1

Processor: Intel® Pentium® 4 2.66 GHz

RAM: 512 Mb DDR

HDD: Seagate 120 Gb 7200 rpm

Monitor: Samsung 17"

OS: MS Windows XP Professional

Computer #2

Processor: Intel® Pentium® 4 2.66 GHz

RAM: 1024 Mb DDR

Video card: Geforce FX 5200 128Mb 128 bit MSI

Hard drive: Seagate 240 Gb 7200 rpm

Monitor: Samsung 19"

OS: MS Windows 7

3. Reporting form

The reporting form of the institution "Vozhegodsk Regional Cultural and Leisure Association" is information containing tables, text, calculations and formatted in a text file using a set of Microsoft Office programs, such as Microsoft Word, Excel, Access.

4. Means of security and information protection

The institution's computers have been installed antivirus Kaspersky CRYSTAL.CRYSTAL keeps your digital world crystal clear. Hybrid Internet Threat Protection instantly eliminates malware, spam and other modern threats, saving computer resources through a combination of cloud and antivirus technologies. do on the internet. The product has optimal default settings, and you do not need to be an IT specialist to effectively manage the protection of all home computers. Use the full potential of the Internet, and entrust security to Kaspersky PURE. The capabilities of Kaspersky PURE allow you to save your valuable documents, photos, favorite audio recordings and movies even if your computer breaks down or is stolen. Special security tools and technologies allow you to create and securely store strong passwords, as well as prevent account theft on websites and applications. Using Kaspersky PURE, you can determine the time, duration and nature of the work of each user in your home. You can also block access to websites with inappropriate content and filter data transmitted using instant messaging programs. Kaspersky PURE - complete solution for protecting home computers, which allows you to centrally manage security and reliably protect your computers from malware and other Internet threats. Special tools such as Parental Control, Password Manager, Backup, etc. provide a level of protection for your personal data that was previously unavailable.

5. Requirements for labor protection and safety.

Basic rights and obligations of employees:

1. Employees of the Company have the right to:

· To conclude, amend and terminate an employment contract in the manner and on the terms established by labor legislation.

· For the provision of work stipulated by the employment contract.

· To a workplace that meets state regulatory requirements for labor protection.

· For timely and full payment of wages in accordance with their qualifications, complexity of work, quantity and quality of work performed.

· For rest provided by the establishment of normal working hours, the provision of weekly days off, non-working holidays, paid holidays.

· Complete and reliable information about working conditions and labor protection requirements at the workplace.

For professional training, retraining and advanced training in the manner prescribed by labor legislation and local regulations of the Company (documented by the QMS procedure "Personnel Training"), including certification in order to maintain the level of professional competence, improve the qualification category or promotion , is regulated by the Regulations on the procedure for attestation of the Company's employees.

· For compensation for harm caused to them in connection with the performance of labor duties, and compensation for moral damage in the manner prescribed by labor legislation.

· On obligatory social insurance in cases stipulated by federal laws.

2. Employees are required to:

· Conscientiously perform their labor duties stipulated by the employment contract and job description.

· Comply with the Internal Labor Regulations and other local regulations adopted in the Company in the prescribed manner.

· Work conscientiously, observe labor discipline, timely and accurately execute the orders of the Company, use all working hours for productive work.

· Carefully treats the property of the Company (including the property of third parties held by the Company, if the Company is responsible for the safety of this property) and other employees.

· Ensure the safety of entrusted property, use equipment effectively, take care of tools, measuring instruments, overalls and other items issued for use by employees.

· Do not disclose information constituting a trade secret and confidential information about the activities of the Company, in accordance with the "Regulations on ensuring the safety of confidential information in the Open Joint Stock Company "Universal Electronic Card of the Vologda Region".

· Behave correctly, with dignity, avoiding deviations from the recognized norms of business communication.

Obligations of the employee in the field of labor protection.

The employee is obliged:

proper use of personal and collective protective equipment;

· be trained in safe methods and techniques for performing work on labor protection, first aid, briefing on labor protection, testing knowledge of labor protection requirements;

undergo mandatory medical examinations;

immediately notify the immediate supervisor or other representatives of the Company about the occurrence of a situation that poses a threat to the life and health of people, the safety of the Company's property (including the property of third parties held by the Company, if the Company is responsible for the safety of this property).

6. Tasks of the head of practice from the enterprise

1) Update installed software

Basically, this operation was carried out manually by selecting the necessary updates, but it was also practiced to update programs through the free application - Software Update Monitor (tracking software updates). Its main purpose is to notify the user about the appearance of new versions of applications with which he works (the result can be seen in Fig. 1).

2) LAN setup

Before setting up a local network through a router for two computers, we will perform the following operations on each of them:

· Setting up a local network for Windows XP

First you need to disable all security programs on this computer (antiviruses, firewalls, firewalls, etc.)

In order for several computers to be recognized and have public access, they must be placed in the same workgroup. To do this, you need to do the following: open the "Properties" tab by calling the context menu on the "My Computer" icon, then go to the "computer name" tab and, by clicking on the "change" button, change the computer name, and click "OK". To set up a local network using a router, you need to make sure that all the IP addresses of computers are located on a single subnet. To do this, you must specify identical settings on all computers. Sometimes the configuration cannot be done without enabling the NetBios protocol. If you have just such a case, then you need to go to the tab " Network connections"And open a window for configuring TCP / IP, then call up additional parameters and enable this same NetBios in the "general" attachment. On this, we can assume that the process is completed.

· LAN setup for Windows 7

The process of setting up a local network for different operating systems is very different. Setting up a local network through a router for Windows 7 is not much more difficult. First, we will need to find out the name of our computer, then go to the "Properties" section, in which we click on the "change settings" button and make the necessary amendments. Then restart your computer for the changes to take effect. The computer name must be in English letters. If it is specified in a different way, then there is a high risk of getting serious errors in the network.

Now we configure automatic generation of the address and DNS. To do this, go to the following path: Control Panel - Control Center - Local Area Network - Properties. In the window that opens, select TCP / IPv4 and check the box for obtaining an IP address automatically. At the end, you will only have to enable NetBios. To do this, you will need to go to the "Protocol Properties" section, in the "Advanced" tab, click on the "WINS" button and check the box next to "Enable NetBios", and then restart the computer. This completes the settings.

3) Installation of additional software

In the institution "Vozhegodsk Regional Cultural and Leisure Association" additional software was installed:

WINRAR 5.00 is a powerful utility for creating and managing archives, containing a whole range of additional useful features. WinRAR is used daily by millions of people around the world to save PC space and transfer files quickly.

Adobe Flash Player is a universal free application that allows you to view pages with dynamic content, colorful special effects, interactive games and video clips, in fig. 2 you can see what Adobe Flash Player looks like.

Reader is a free, proven standard for securely viewing, printing, and annotating PDF documents. It is the only PDF viewer that allows you to open and interact with all types of PDF content, including forms and multimedia objects, as shown in Figure 1. 3.

FineReader is a text recognition program that allows you to quickly and accurately convert document images and PDF files into editable electronic formats without the need for retyping.

You can get an image for recognition not only with a scanner: it is enough to have a digital camera or a mobile phone with a built-in camera with you, the result can be seen in Fig. 4.

microsoft office antivirus installation

4) Install Microsoft Office 2007

Before installing Office 2007, we need to uninstall the old version, for this we go to the “my computer” folder, then select “add / remove programs” and remove the old version of Office 2003, after the removal is completed, restart the computer. After restarting the computer, load the Office 2007 image from portable media and start the installation following the instructions. After installation, it is best to reboot the copter for the changes to take effect.

) Installing Windows7 operating system:

Windows is reinstalled using hard disk partitioning programs, both standard and third-party such as: Acronis Disk Director.

· The first thing to do before installing Windows is to make a copy of the data we need using a memory card or CD-ROM.

· Now we need to go into the BIOS of the computer to set the boot from a CD or from a USB flash drive. Save the changes and restart the computer by pressing the F10 key.

· The third step is to prepare the hard disk to install the new OS. Here we perform the procedure of partitioning the disk into a file NTFS system using Acronis Disk Director. From under BIOSS, launch Acronis and perform the following steps: delete the previous sections of the hard disk and create new ones, specify the amount of memory that is required for the new OS, specify the NTFS file system and click the "Start" button. After completing these procedures, close the program and remove the disk.

· The fourth step is to install the new OS itself. We launch the installation image from under the BIOS and begin the installation. We indicate the disk partition we need and click next, and wait for the installation process to complete.

After the installation of the OS is completed, we configure it.

Install drivers using the Driver Pack Solution program.

Install the programs we need from the ChipWPI program collection (antivirus, MS Office, codecs, archiver).

· Setting up a local network.

6) Install Adobe Photoshop CS5

1. Install Adobe Photoshop.

2. We go to the Adobe website.

Choose Russian | windows | 1000.9 MB Download now.

Download Akami Download Manager. Open it and open the site again. Click "Download Now". Select the directory where the files will be downloaded.

Password entry

Download Adobe Photoshop CS5 Extended 12.0 Final Multilanguage. Click on Set-up.exe, the result of this operation can be seen in fig. 5.

Click the “Skip and continue” button, wait for the installation programs to initialize, the process of this operation can be seen in Fig.6.

The next step in installing Adobe Photoshop CS5 is to enter the serial number that was given when purchasing the software.

We are waiting for the installation to complete, the process can be seen in Fig. 9.

At the end of the installation, click the "Finish" button, fig. 10.

We launch the program using a shortcut on the desktop or through the Start menu, we get the working window of the program, which can be seen in Fig. 11. The program is ready to use.

7) Antivirus settings

When setting up the network, there was a problem with the definition of computers, to solve it, it was necessary to disable the firewall in the Kaspersky anti-virus. To do this, we perform the following action: in the system tray (lower corner of the screen) we find the antivirus icon and click on it. Next, select "Security Control" on the antivirus panel. Select "Protection Center" on the left. At the bottom right, click "Work online".

A new window "Protection components for your computer" will open. On the left, select "Network protection", then look for "Firewall". And by clicking on the dot opposite, turn off the "Firewall". This is the firewall in Kaspersky "CRYSTAL".

The license for the use of Kaspersky anti-virus programs was also renewed.

Conclusion

Passage of industrial practice is an important element of the educational process for the preparation of a specialist in the field of programming.

During the production practice in the institution "Vozhegodsk Regional Cultural and Leisure Association" all the acquired skills of theoretical training were fixed in production.

The wide coverage of industries that I had to deal with in practice allowed me to better assimilate the studied theoretical material obtained in the classroom at the technical school.

I mastered some of the subtleties of using software in practice, understood how some programs work, subroutines that were not clear to me, realized their importance in practical activities, increased my knowledge of programs: Adobe Photoshop, Adobe Reader, Microsoft Word and others.

Practical activities helped me learn how to independently solve a certain range of tasks that arise in the course of a programmer's work. The Internet, where you can currently find a lot of useful information in the field of programming, has also been of great help in solving the tasks.

Bibliography

1. Scott Kelby - Adobe Photoshop CS6. Handbook of Digital Photography (2013) PDF.

2. Broido V. L. Computing systems, networks and telecommunications: Textbook for universities / V.L. Broido. - St. Petersburg: Peter, 2003. - 688 p.

3. Shafrin Yu.A. Fundamentals of computer technology / Yu.A. Shafrin. - M.: ABF, 2001. - 560 p.

4. Olifer V.G., Olifer N.A. Computer networks. Principles, technologies, protocols /V.G. Olifer, N.A. Olifer. - St. Petersburg: Peter, 2002. - 672 p.

1. Introduction

In our age of computer technology, no company can do without the use of computers. And if there are several computers, then they, as a rule, are combined into a local area network (LAN).

A computer network is a system of interconnected computers, as well as, possibly, other devices, which are called nodes (workstations) of the network. All computers in the network are connected to each other and can exchange information.

As a result of combining computers into a network, opportunities arise: to increase the speed of information message transmission, to quickly exchange information between users, to expand the list of services provided to users by combining significant computing power in a network with a wide range of different software and peripheral equipment. The use of distributed resources (printers, scanners, CD-ROMs, etc.), the availability of structured information and the effective search for the necessary data. Networks provide enormous advantages that are unattainable when using computers separately. Among them: the division of processor resources. When the processor resources are divided, it is possible to use computing power for simultaneous data processing by all stations included in the network. Data separation. Data sharing allows you to manage databases from any workstations that need information. Shared access to the Internet. LAN allows you to provide access to the Internet to all your clients using just one access channel. Resource sharing. LAN allows you to economically use expensive resources (printers, plotters, etc.) and access them from all connected workstations. multimedia capabilities. Modern high-speed technologies allow the transmission of audio and video information in real time, which allows you to conduct video conferences and communicate over the network without leaving your workplace.

Now, no large enterprise can do without a LAN.

The purpose of this industrial professional practice is to study the features of operation and maintenance of computer equipment and computer networks.

At present, the enterprise network continues to develop. New computers are added to the workplaces, as a result of which the number of requests to the servers increases. Therefore, the main direction of network modernization is the replacement of servers with more modern ones. The first steps were taken in early 2004 when one of the mail servers and the TKIIP information hub were replaced. Also, modernization requires most of the jobs at the junction stations.

At the enterprise in 1998, a bus topology was used to build a network, i.e. all computers were connected in series one after another, using a cable system. In this case, the technology of the "Ethernet" standard was used.

Ethernet is the most widely used local area network standard. Ethernet is usually understood as any of the variants of this technology: Ethernet, Fast Ethernet, Gigabit Ethernet. All kinds of Ethernet standards use the same media separation method, the CSMA/CD method, a multiple access method with carrier sense and collision detection.

In a narrower sense, Ethernet is a network standard with a data transfer rate of 10 Mbps. The historical first networks of Ethernet technology were created on coaxial cable. Other physical layer specifications for this standard have since been defined. The physical specifications of Ethernet technology today include data transmission media:

10 Base-5 is a 0.5 inch coaxial cable called “thick” coax. It has a wave impedance of 50 ohms. Maximum segment length 500 meters without repeaters;

10 Base-2 is a 0.25 inch coaxial cable called “thin” coax. It has a wave impedance of 50 ohms. The maximum segment length is 185 meters without repeaters;

10 Base-T - Category 3 Unshielded Twisted Pair (UTP) cable. Forms a hub-based star topology. The distance between the hub and the end node is no more than 100 meters;

10 Base-F - fiber optic cable. The topology is similar to that of the 10 Base-T standard. There are several options for this specification - FOIRL (distance up to 1000 meters), 10 Base-FL (up to 2000 meters), 10 Base-FB (up to 2000 meters).

The number 10 in these names indicates the bit rate of these standards - 10 Mbps.

An important phenomenon in Ethernet networks is a collision - a situation when two stations simultaneously try to transmit a data frame over a common medium. This is a consequence of the random access method adopted.

But over time, the number of computers increased, and data transmission over the bus became impossible due to the loss of speed. In this case, the enterprise decided to use the ZVEZDA network topology. In this case, there is a server to which all computers participating in the local area network are directly connected. To build the network, the Fast Ethernet technology was chosen and applied, and Gigabit Ethernet is currently being used.

Fast Ethernet: In 1995, the IEEE 802.3 committee adopted the Fast Ethernet specification as the 802.3u standard, which is not a standalone standard, but an addition to the existing 802.3 standard. The MAC and LLC levels in Fast Ethernet remain exactly the same as in Ethernet. The access method also remained the same - CSMA/CD. This ensured the continuity and consistency of the 10 Mbps and 100 Mbps networks. All the differences between Fast Ethernet and Ethernet technologies are concentrated at the physical level. A more complex structure of the physical layer of technology is due to the fact that it uses three options for cable systems:

Fiber optic multi-mode cable, two fibers are used;

Coaxial cable is not included in the number of permitted transmission media for Fast Ethernet technology. Networks based on this technology always have a hierarchical tree structure built on hubs. The network diameter is reduced to 200 m (for a hub-based network). The speed, in comparison with Ethernet, is increased by 10 times due to the reduction of interframe delay. The technology operates in full duplex mode. The 802.3u standard established 3 different specifications for the Fast Ethernet physical layer, giving them the following names:

100Base-TX for two-pair UTP category 5 unshielded twisted pair or STP type 1 shielded twisted pair. Maximum segment length 100m;

100Base-T4 for 4-pair UTP category 3, 4 or 5 unshielded twisted pair cable. Maximum segment length is 100 m;

100Base-FX for multi-mode fiber optic cable, two fibers are used. The maximum segment length is 412 m (half duplex), 2 km (full duplex).

Gigabit Ethernet: Quite quickly after the introduction of Fast Ethernet products on the market, network integrators and administrators felt certain limitations when building corporate networks. In many cases, servers connected over a 100-megabit link overloaded network backbones. There was a need for the next level in the hierarchy of speeds. In this regard, in June 1995, the IEEE High-Speed ​​Technology Research Group was assigned to consider the possibility of developing an Ethernet standard with even higher bit rates. The category 5 twisted-pair standard was finally adopted in 1999. The transfer rate in Gigabit Ethernet is 1000 Mbps. The developers have retained a large degree of continuity with Ethernet and Fast Ethernet technologies: the same frame formats work in half-duplex and full-duplex modes, supporting the same CSMA / CD access method on a shared medium with minimal changes. In the summer of 1998, the 802.3z standard was adopted, which defines the use of three types of cable as a physical medium: multimode fiber optic (distance up to 500 m), single-mode fiber optic (distance up to 5000 m) and double coaxial (twin ax), through which data is transmitted over two shielded copper conductors up to 25 meters.

The 802.3ab ad hoc working group has developed a variant of Gigabit Ethernet over Category 5 UTP. To achieve 1000 Mbps, four unshielded twisted pairs are used simultaneously at 250 Mbps.

4. Network hardware

Workstations are any computers that, through a local network, access resources stored on a server.

basically all enterprise workstations have the following configuration:

Processor Intel Pentium III 1.3 GHz;

RAM 256 Mb;

LAN 10/100Mb/s;

Hard drive IDE 40Gb.

Some workstations have a CD-ROM drive, sound card and speakers, HP 1200 printers.

4.3 Switches

A switch is a multi-port link layer device that "learns" MAC addresses and stores them in an internal lookup table. A temporary switched connection is created between the sender and the intended recipient of the frame, over which the frame is transmitted.

To combine computers into a network, 3Com Super Stack Switch 4900, 4924, 4400 SE switches and 4-port 1000BASE-SX optical modules are used to connect trunk channels.

Central Distribution 3Com Super Stack Switch 4900, 4900SX:

IEEE 802.1p, 1000Base-TX;

Throughput 23 million. packets / s (24 ports);

Access Method CSMA/CD;

Size 6.6*44*37 (cm), weight 6.5kg;

Permissible ambient humidity 10%~90%;

3Com Super Stack 3 Switch 4400SE Network Edge Switch

IEEE 802.3ad, 1000Base-SX;

Stack up to 192 10/100Mbit/s ports;

Bandwidth 6.6 Mpps (24 ports);

UTP category 5e physical media;

Mains supply 100-240V (50-60Hz);

Size 6.6*44*41 (cm), weight 6.3kg;

Permissible ambient temperature 00C~40C;

Permissible ambient humidity 10%~90%.

Uses Gigabit Ethernet switching without blocking at the highest possible speed, using XRN technology can improve performance up to 48Gbps.

Layer 3 switching is also used, supporting unicast IP routing and OSPF protocols. RIP / RIPv2 and CIDR the presence of a function to control UDP traffic. Uses advanced security features, RADIUS client support, and support for Routed Access Control Lists to provide automated user access to network resources. Supports 3Com Gigabit Multilayer Switching (GMS) software and provides advanced Layer 2 switching. They have an advanced network management function. The 3Com Network Supervisor software used (simplifies network administration tasks) detects devices connected to the network, displays their status in a graphical diagram and manages them.

4.4 Network adapters

Network adapters are designed to receive and transmit data on the network. The computers of the department mainly use D-Link 530TX 10/100 Mbit/s network cards. Support 32bit PCI bus in Lokal Bus mode auto-detect Nway, comply with IEEE 802.3u/ 8702.3 standard, support Plug and Play, ACPI, Wol, and power management.

4.5 Modems

Modem - a functional device that provides modulation and demodulation of signals; a device that converts digital signals to analog form and vice versa for transmission over analog type communication lines. Characteristics of the external ADSL modem:

Reception at a speed of 8 Mb / s and transmission up to 1 Mb / s;

RJ-11 connector for line connection;

Ethernet interface 10/100Mb/s with auto cable detection;

Work in bridge and router modes, routing using a multi-address policy;

Compliant with G.PMT(G.992.1) standards;

Service Quality Management (UBR/CBR/VBR);

Configuration via WEB-interface or Telnet;

Administration and SNMP;

System requirements;

PC with Ethernet interface 10/100 Mb/s;

CD or DVD drive;

Telephone line with ADSL access service from an Internet provider.

4.6 Cable system

Equally important in designing a local network is the choice of cable subsystem, since a reliable LAN provides reliable connections. In other words, all connections in the network must be made with high quality, unreliable contacts and other physical damage are unacceptable. This is given such importance because it is still a very laborious task to find an open or damaged connection in a failed network.

The answer to the high quality requirements of the cable system was structured cable systems, which are a set of switching elements (cables, connectors, connectors, cross panels and cabinets), as well as a method for their joint use, which allows you to create regular, easily expandable communication structures in computer networks .

Versatility;

Increase in service life;

Reliability.

Overview of cable equipment.

Twisted pair (UTP / STP, unshielded / shielded twisted pair) is currently the most common signal transmission medium in local networks. UTP/STP cables are used in Ethernet, Token Ring, and ARCnet networks. They differ in categories (depending on the bandwidth) and type of conductors (flexible or solid). In a Category 5 cable, as a rule, there are eight conductors intertwined in pairs (that is, four pairs).

All cables consist of 4 pairs (two for file transfer, the other two for voice). RJ-45 plugs and sockets are used to connect cables to equipment. There were also cables of category 6, with a frequency of up to 200 MHz, and category 7, with a frequency of up to 600 MHz, which are necessarily shielded.

A structured cabling system based on Category 5 twisted pair has a very high flexibility in use. Her idea is as follows.

A structured cabling system is built hierarchically, with a main line and numerous branches from it. Typical hierarchical structure structured cabling system includes:

Horizontal subsystems (within the floor);

Vertical subsystems (inside the building);

Campus subsystem (within the same territory with several buildings).

Using a structured cabling system instead of chaotically routed cables provides a business with many benefits:

Versatility;

Increase in service life;

Reducing the cost of adding new users and changing their placements;

Possibility of easy network expansion;

Providing more efficient service;

Reliability.

The horizontal subsystem is characterized by a large number of cable branches, since it must be routed to each user outlet. Therefore, the cable used in horizontal wiring is subject to increased requirements for the convenience of making branches, as well as the convenience of laying it indoors. When choosing a cable, the following characteristics are taken into account: bandwidth, distance, physical security, electromagnetic interference immunity, cost.

The horizontal subsystem, that is, the floor subsystem, can be divided into three parts:

The subscriber part consists of RJ-45 sockets connected by a patch cord;

The stationary part is a patch cord that connects sockets to a cabinet with network equipment;

The switching part is the patch cord between the switch and the sockets on the patch panel.

The vertical subsystem, the cable that connects the floors of the building, must transmit data over longer distances and at a higher speed compared to the horizontal subsystem cable. It consists of longer cable sections, the number of branches is much less than in the horizontal subsystem.

Optical fiber, as its name implies, transmits signals using pulses of light radiation. Semiconductor lasers and LEDs are used as light sources. Optical fiber is divided into single-mode and multi-mode.

Single-mode fiber is very thin, its diameter is about 10 microns. Due to this, the light pulse passing through the fiber is less often reflected from its inner surface, which provides less attenuation. Accordingly, single-mode fiber provides greater range without the use of repeaters. The theoretical throughput of single-mode fiber is 10 Gbps. Its main disadvantages are high cost and high complexity of installation. Single-mode fiber is mainly used in telephony.

Multimode fiber has a larger diameter - 50 or 62.5 microns. This type of optical fiber is most often used in computer networks. The greater attenuation in multimode fiber is due to the higher dispersion of light in it, due to which its throughput is significantly lower - theoretically it is 2.5 Gb / s.

All active switching equipment is located in special cabinets made of transparent plastic, which allows you to visually see all the equipment. Patch panels, converters, switches, hubs, etc. are used. In the departments, the wires are mounted on the walls using special boxes or on the ceiling under false ceilings. Everything is organized simply, conveniently and neatly. Special connectors are used to connect the optical cable to active equipment.

5. Network software and network administration

The wide variety of types of computers used in computer networks entails a variety of operating systems: for workstations, for department-level network servers, and enterprise-level servers as a whole. They may have different requirements for performance and functionality, it is desirable that they have a compatibility property that would allow different operating systems to work together.

Network operating systems can be divided into two groups: department-wide and enterprise-wide. OS for departments or workgroups provide a set of network services, including the sharing of files, applications and printers. They should also provide fault-tolerant properties, for example, work with RAID arrays, support cluster architectures. Departmental network OSs are typically easier to install and manage than enterprise network OSes. They have fewer features, less data protection, and weaker interoperability with other types of networks, as well as poorer performance.

An enterprise-scale network operating system, first of all, must have the basic properties of any corporate products, including:

Scalability, that is, the ability to work equally well in a wide range of different quantitative characteristics of the network;

Compatibility with other products, that is, the ability to work in a complex heterogeneous environment of the Internet in plug-and-play mode.

The criteria for choosing an enterprise-scale OS are the following characteristics:

Organic support for multi-server network, high efficiency of file operations;

Possibility of effective integration with other operating systems, availability of a centralized scalable help desk, good development prospects;

Effective work of remote users, various services: file service, print service, data security and fault tolerance, data archiving, messaging service, various databases and others;

Various hardware and software host platforms: IBM SNA, DEC NSA, UNIX;

Various transport protocols: TCP/IP, IPX/SPX, NetBIOS, Appletalk;

Support for a variety of end user operating systems: DOS, UNIX, OS/2, Mac;

Support for network equipment standards Ethernet, Token Ring, FDDI, ARCnet;

Availability of popular application interfaces and mechanisms for calling remote RPC procedures;

Ability to interact with the network control and management system, support for SNMP network management standards.

Of course, none of the existing network operating systems fully meets the listed requirements, so the choice of a network operating system, as a rule, is carried out taking into account the production situation and experience.

One of the main tasks at the JSC Lepse enterprise is information protection.

Information security tools include:

Passwords installed on computers;

Antivirus programs;

Power protection for servers and some workstations.

The enterprise created the 1st department, which is responsible for the archive of classified information. Before accepting a new employee for work or practice (who will directly work with a computer and data), a person must be familiar with the instructions for protecting information. He will also need to obtain a certificate from the first department.

Information stored directly on computers is protected by restricting access for administrators and guests, each with a separate login and password. User groups are created with certain rights and powers (for example: user) of access to network resources. That is, for an employee with a certain position, certain access rights and the amount of information related purely to his activities are provided. Thus, the more rights, the more information the user has. The administrator can perform all actions: enter new data into the database, delete records from the database, and perform various settings of systems and programs. And ordinary users can only perform certain actions. For example, viewing and searching for the necessary information.

Virus protection can be provided using common antivirus programs such as Kaspersky Anti-Virus, Dr.Web and McAfee others. The company primarily uses McAfee.

In order to protect information from viruses and from its leakage, work on the Internet takes place on separate computers that are not connected to the network.

7. Power protection devices

To protect servers, as well as a number of simple workstations from power surges, the enterprise uses sources uninterruptible power supply. UPS (Uninterruptible Power Supply) uninterruptible power supplies provide all degrees of computer power protection. They are also the most expensive of all power protection devices. Whereas backup power supplies (BPS) supply power to the computer only in the event of an AC power failure, uninterruptible power supplies (UPS) supply the computer with modulated DC power continuously from the battery. AC mains power is not supplied directly to the computer power supply, it only constantly charges the battery of the uninterruptible power supply. As a result, the computer is isolated from any AC voltage anomalies. Like a backup power supply, an uninterruptible power supply can only provide a computer for a certain period of time (depending on the load), which allows the user to save the results of their work and shut down the operating system in a regular way. An uninterruptible power supply unit supplies voltage to the computer continuously, so when using it, there is no problem with the duration of switching to an autonomous battery mode. High-quality uninterruptible power supplies provide uninterrupted power to the computer, as well as correcting voltage dips and protecting against surges and peaks that occur in the AC mains.

The company uses uninterruptible power supplies APC Smart-UPS 5000VA 230V.

Specifications of uninterruptible power supplies APC Smart-UPS 5000VA 230V are shown in Table 1.

Table 1 - technical characteristics of uninterruptible power supplies APC Smart-UPS 5000VA 230V.

8. Feasibility study of the network

The main factor in the feasibility study of the network is the indicator of the total cost of creating a LAN. The total cost indicator consists of the following parts:

LAN development costs;

Costs for equipment and materials;

Marketing research costs.

The total cost of creating a LAN is determined by formula (1):

The total cost of creating a LAN;

LAN development costs;

Taxes included on the cost of creating a LAN;

Costs for equipment and materials (calculated when designing a LAN);

The cost of marketing research can be taken in the amount of 10-20% of .

The amount of taxes is calculated by the formula (2):

(2),

General wage fund for employees involved in the creation of the LAN;

The total rate of taxes (other than transport), including the cost of creating a LAN, can be taken at a rate of 10%.

The total wage fund of employees involved in the creation of the LAN is determined by formula (3):

(3),

The time of participation of a specialist of a certain qualification in the creation of a LAN (data are taken from Table 3);

The number of specialists of a certain qualification;

The monthly salary of an employee in accordance with his category or tariff category of the UTS of the public sector;

Shift duration (8 hours);

Average number of working days per month (21 days);

Bonus provided for employees 20-25% of;

Payments according to the district coefficient (Kirov 15% of (+P)).

LAN development costs are calculated by formula (4):

Project development and documentation costs;

Installation and installation costs;

Costs for commissioning;

Other costs associated with the creation of a LAN (study of tasks, literature, patents, economic calculations, etc.);

The costs for the development of the project and documentation are determined by the formula (5):

The cost of paying salaries to employees involved in the development of the LAN;

Award to employees involved in the development of the project and documentation;

District coefficient for employees involved in the development of the project and documentation (15%);

General rate of contributions for social needs (26%);

Wage fund for employees involved in the development of the project and documentation (includes salary bonus and payments according to the district coefficient);

Adjustment costs of the organization that is engaged in the creation of the LAN. They can be taken in the amount of 100-200% of.

Other costs for the creation of a LAN are 15-20% of the costs , and and are calculated by formula (7):

The cost of materials and equipment is calculated when designing the LAN, and their price is taken from the LAN design.

The overall cost estimate is presented in Table 2.

Table 2.

The "other" line includes: sockets, mounting cabinets, brackets, network adapters, network laying works, etc.

As a result, the total cost of building the network amounted to about 86 million rubles. The salary of the persons involved in the development and construction of the network is not indicated, since the network of the plant was not built immediately, but as needed, it was modified over the course of several years. Therefore, it is almost impossible to calculate the salary of persons involved in the development and construction of the network.

9. Measures for preventive maintenance of military equipment

Preventive maintenance of computers can be divided into:

emergency;

Planned (monthly, annual);

Preventive maintenance of copiers.

Emergency maintenance is carried out when the SVT fails. Maintenance is carried out by a specialist in the maintenance of BT facilities. It includes the following types of work:

Diagnostics of hardware and software of a computer or copy equipment;

Elimination of the hardware (replacement of the failed unit with a serviceable one) or software malfunction(OS reinstallation, software reinstallation).

Monthly preventive maintenance includes:

Removing dust from the external parts of the PC (when the power is off);

Visual inspection of cables: power supply, monitor interface cables, keyboard, mouse, printer, LAN cable;

Cleaning the magnetic heads of floppy drives with a cleaning disk;

Prevention of the keyboard, monitor, processor and other devices (checking with special test programs and external inspection).

In the course of the annual preventive maintenance of SVT facilities, the following actions are performed:

Performing a visual inspection of the computer;

Checking the performance of the cooling system of the processor, hard drive, video card;

Cleaning the monitor, keyboard, mouse and housing from dust with cleaning products;

Cleaning the drive and optical drive special cleaning diskettes and optical disks;

defragmentation of the hard disk;

Checking hard disk for viruses by antivirus programs;

Checking the compliance of the programs installed on the computer with the programs recorded in the data sheet.

Periodic maintenance (TO) of copiers is also carried out. TO includes:

Cleaning the printer outside from dust and waste from the printing process;

Cleaning the inside of the printer (cleaning the interior mirror with a cleaning brush, wiping the rollers with alcohol);

Check print quality with a test.

If noise occurs during computer operation or when the PC or printer becomes very hot, the cooling systems are cleaned:

Dust removal with a brush or a piece of cloth (outside and inside);

Removal of foreign objects that got into the fan / radiator during operation;

Fan shaft lubrication.

10. Diagnostic tools and maintenance

10.1 Software and hardware diagnostics

All methods for troubleshooting and diagnosing devices can be divided into two main groups:

hardware method;

Program method.

Diagnostic software tools include various programs and utilities with which you can check your computer:

MHDD 4.6 is designed to test a hard drive for logical and hardware errors;

MemoryTest is designed to test memory;

Actra1.40 is a utility that collects all information about the computer, as well as all information about the software that is installed on the computer.

The hardware method includes an external inspection, checking the correctness of the connection using special devices - testers. The SLT3 (UTP) and SLT3S (UTP/STP/FTP) tester shown in Figure 3 is designed to test the copper cable.

Figure 3 - Testers

SLT3 (UTP) - light, small-sized testers shown in Figure 3a, consist of 2 parts (master and remote), have built-in 3 RJ45 sockets for testing, respectively 3rd cable stripping methods (sequences) USOC, 568A, 568B For ease of transportation, both parts of the tester are connected to each other (placed in a case, fixed on the installer's belt), while the batteries are turned off, thereby extending their service life. The tester is able to detect short circuits, line breaks and mismatches in this sequence (strands or pairs reversed). LED diodes in a certain way signal us about all these errors.

For attenuation measurement optical lines it is recommended to use the FLT4 type tester shown in Figure 3 b. The tester consists of 2nd parts: light signal source (FLT4-S) and receiver optical power meter (FLT4-M). The light source is very easy to maintain. The only manually set parameter is the wavelength of the emitted signal (850 nm or 1300 nm). The source has a switch, which also signals to us the need to replace the batteries (one power supply with voltage in an EV of the Krone type). The receiver is equipped with a switch, a button for setting the ratio level (zeroing the tester when the "reference" cord is turned on), a button for selecting the wavelength, and a button for selecting the measurement option: attenuation or optical power. The measurement results are displayed on the LCD screen.

10.2 Tools and instruments

There are special tools that allow you to identify problems and fix them. These include:

A simple set of tools for disassembly and assembly. Necessary for elementary maintenance of a PC at the level of boards and nodes: screwdrivers (star-shaped, simple), tweezers, a device for extracting microcircuits, pliers, a flashlight, a protective kit for removing electrostatic voltage, tools for minor repairs (nippers, a file);

Diagnostic devices and programs for testing PC components: boot disks or floppy disks, a self-test board for displaying POST diagnostic codes if any errors are detected;

Instruments for measuring voltage and resistance: digital multimeter, logic probes, single pulse generator for testing network circuits, for forcing a pulse with a duration of 1.5 to 10 µs into the circuit, a power outlet tester for testing an electrical outlet.

Chemical preparations: solution for wiping contacts, a spray gun with coolant, a can of compressed gas for cleaning PC parts;

Special improvised tools;

Test connectors for testing serial and parallel ports, memory testers, scanner for network cables;

Markers, pens, notebooks;

Spare parts, fasteners.

10.3 Troubleshooting methods

Troubleshooting any node or block of a computer can be carried out by two main methods, such as external inspection and testing of individual blocks.

External examination includes:

Checking the correct connection of computer blocks to each other;

Check cables and connectors and replace if necessary;

Checking microcircuits for burnt contacts.

Testing individual blocks includes:

Checking computer blocks with diagnostic programs;

Checking computer blocks with hardware diagnostic tools.

If an error or any malfunction is found, it must be eliminated. And if the malfunction cannot be eliminated, you need to replace the faulty computer unit with a serviceable one.

There is also a program of preventive measures, which includes two types of activities:

Passive prevention - measures aimed at protecting the PC from external influences: creating conditions, placement, use of network filters, uninterruptible power supplies, proper heat dissipation, exclusion of sunlight, grounding;

Active Prevention - performing operations aimed at extending the uptime of the PC: cleaning the PC, performing operations for fans and the CPU to remove heat, scanning the hard disk and deleting unnecessary information, periodically monitoring the PC.

11. Ensuring conditions for the safe operation and repair of military equipment

Prohibited when power is on:

Move computer blocks, connect and disconnect them;

Connect and disconnect the interface cables of the keyboard, mouse, monitor, printer;

Put diskettes, papers, plates, cups, rags and other items on the computer;

If it is necessary to move the PC, call the specialists of the system and technical support department. Moving computers and devices connected to them by PC users is strictly prohibited.

It is forbidden to eat at workplaces equipped with a PC.

In case of malfunctions, contact the specialists of the relevant inspection departments.

When repairing BT equipment, the following rules must be observed:

Disconnect the computer from the network;

After opening the case, you need to remove the static voltage;

Never lay boards on a conductive metal surface.

Conclusion

During the course of industrial and professional practice at JSC Lepse, the company's network, its structure, network operating system, cable system, cable and switching equipment, network software were studied. Knowledge was gained in the field of setting up and administering a network, repair and maintenance of personal computers, scanning and printing devices. Skills were acquired to repair and adjust workstations, laser and inkjet printers, as well as to install servers and prepare workstations for work.

Bibliography

1. Mark Minasi "Your PC: device, principle of operation, modernization, maintenance and repair", St. Petersburg: KORONA print, 2004.

2. Magazine "World of PC"

3. www.morePC.ru

4. Lectures "Maintenance of SVT and KS"

5. "Hardware of local networks". Encyclopedia. M. Guk - St. Petersburg; publishing house "Peter", 2000.

6. “Computer networks. Principles, technologies, protocols”. V.G. Olifer, N.A. Olifer - St. Petersburg; publishing house "Peter", 2000.

7. Regulatory documents of the Lepse plant.

Introduction
Chapter 1. Analysis of the structure of the organization, description of the hardware and software of the organization
1.1 Structure of the organization
1.2 Description of the organization's hardware
1.3 Description of the software used in the organization
1.4 Description of the activities of the information technology department of the organization
Chapter 2. Ensuring stable operation of computer systems and complexes
2.1 List of instructions required for organizing the workplace of a computer system adjuster or a hardware and software system adjuster.
2.2 Examine the system of preventive maintenance of computers in the organization
2.3 Description of monitoring, diagnostics and recovery of computer systems and complexes
2.4 Identification of shortcomings in the system for ensuring the stable operation of computer systems and complexes. Suggestions for improving this system
Chapter 3. Description of the information system used in the organization
3.1 Analysis/development of the structure of the information system
3.2 Description of the database management system/software used for development
3.3 Description of the main objects of the information system
3.4 Instructions for users to work with the information system
3.4.1 Purpose of the program
3.4.2 Program execution conditions
3.4.3 Program execution
3.4.4 Operator messages
3.5 Description of means, methods of information protection when working with an information system
Conclusion
List of sources used

Introduction

Today the whole world communicates with the help of computers. Every family has high-tech machines; not a single enterprise works without them. Only not everyone knows how to talk to a computer in its language and make it understand the language of a person. To be an expert in computer systems means to be one step ahead of time. After all, nothing in the world is developing as fast as computer technology. No wonder they say: "The computer is outdated as soon as it went on sale."

Having learned how computer systems are arranged, you begin to understand the language of numbers, to know computer-aided design systems, microprocessor systems and peripheral equipment. In other words, you begin to speak the same language with the computer. He, as a friend, teaches to solve problems, assess risks and make decisions in non-standard situations, which is very much appreciated by employers. The range of application of the knowledge of a computer network specialist is wide: from small salons to large enterprises - wherever there are computers, a system administrator is required - a specialist in computer systems and complexes.

In order to better prepare specialists for this profession, practical skills are required. For this purpose, practical classes are provided in educational institutions.

Practice in the profile of the specialty is a form of training in organizations (enterprises) of different forms of ownership and organizational and legal forms.

Practice in the profile of the specialty is carried out in order to study the general principles of the functioning of organizations and institutions for labor management and regulation of social and labor relations, employment services; principles of organizing the work of services and divisions dealing with the selection, placement and accounting of personnel, personnel departments, labor and wages, personnel management departments; as well as analysis of documentation supporting the activities of these services. It allows you to combine theoretical training with practical activities in specific workplaces. Practice tasks include:

• monitoring, diagnostics and recovery of computer systems and complexes
• system maintenance of computer systems and complexes
• debugging of hardware-software systems and complexes;
• installation, configuration and configuration of the operating system, drivers, resident programs;
• maintaining customer databases;
• demonstrating the capabilities of complex technical systems;
• advising on the use of complex technical systems;
• informing the consumer about the operating conditions of the selected options for technical solutions, license agreements.
• During the practice in the specialty profile, it is necessary to perform the following types of work:
• characteristics of the enterprise. Analysis of the external and internal environment of the organization;
• description of the technical and software park of the enterprise;
• development of methods and regulations for preventive maintenance of computer equipment;
• development of a system for modernizing the technical and software park of the enterprise;
• development of information security policy rules;
• designing the organization's database structure;
• general description of the configuration/database, interface, input and output forms;
• configuring and setting up the database, setting data access privileges;
• drawing up instructions for the user when using a particular database management system;
• developing a presentation of the organization's products.

Chapter 1. Analysis of the structure of the organization, description of the hardware and software of the organization

1.1. Organization structure

Princip Company is one of the largest companies in the city of Smolensk, specializing in the production and sale of computers, solving network integration issues, as well as in the supply of office and mobile equipment, components and consumables.

The stores offer the widest selection of modern computer equipment: personal and laptop computers, monitors, office equipment from leading manufacturers (Samsung, Acer, Phillips, Toshiba, MSI, Intel, AMD, Asus, Dell, LG, Canon, Epson and many others).

Huge selection of consumables (paper, cartridges for inkjet and laser printers, toner, ink, etc.)

Today it is a supplier of many large state and commercial organizations in Smolensk and the Smolensk region.

It also became the first Smolensk manufacturer of computers certified according to GOST and having an international quality certificate ISO 9001. This allows us to speed up and simplify the process of servicing our customers' equipment and offer computers of the highest quality at the best prices.

It is the first Smolensk company to be a Gold Certified Partner of Microsoft with the competence of "Management of licenses in organizations", offers customers software for various programs licensing, which allows you to choose the best option.

1.2. Description of the organization's hardware

Nowadays, the vast majority of organizations use modern automated systems in their work and computer equipment, software and storage media.

The institution has 12 computers.

The computer hardware for the workstation includes:

• processor type and frequency - Intel Core 2 Duo 2.4 Hz;
• the amount of RAM - 2048 MB;
• hard disk type and size - WDCWD1600AAJS-61 WAA0 (IDE500GB);
• a type motherboard- integrated;
• type of video card - built-in;
• type CD-ROM-DVD-R;
• sound card type - built-in;
• network card type - ETHERNET (100 MB/s);
• BIOS type - rewritable;
• monitor type and size - LCD 17''.

Workstation PC system software includes:

• OS - Windows XP Professional;
• manufacturer - Microsoft;
• bit depth OS-32;
• the file system used is NTFS;
• type of supported interface - graphical.

Minimum requirements for computer architecture when installing this OS:

• 2.4 Hz Intel processor or faster;
• at least 64 MB of RAM (at least 128 MB recommended);
• at least 1.5 GB of free hard disk space;
• CD or DVD drive;
• keyboard, Microsoft Mouse.

The organization has an S5000MB (S5332LNi) server as a server computer: Core i5-4590 / 8 GB / 2 x 1 TB SATA RAID.

The server computer hardware includes:

• Intel processor
• Drive Interface SATA 6Gb/s
• Type of HDD
• RAM 8 GB
• Network card 10/100/1000 Mbps

The organization uses the following peripherals HP LASERJET P2035, HP LASERJET PRO COLOR CP1025, HP LASERJET PRO P1102, HP SCANJET 300, Samsung ML-1210

1.3. Description of the software used in the organization

Software is used as the operating system Microsoft Windows XP Professional.

Personal computer software:

• Microsoft Office 2007
• KasperskyAnti-Virus
• 1C: Enterprise (1C: Accounting).
• 1C: TRADE AND WAREHOUSE 7.7
• Windows 2000 Server SP4

Windows XP Professional is an operating system (OS) of the Windows NT family of Microsoft Corporation. It was released on April 25, 2005 as a version of Windows XP for the personal computer platform.

Kaspersky Antivirus (KAV) is antivirus software developed by Kaspersky Lab. Provides the user with protection against viruses, Trojans, spyware, rootkits, adware, and unknown threats using proactive protection that includes the HIPS component (only for older versions called Kaspersky Internet Security 2009+, where '+' is the sequence number of the previous register, annually increased by one in accordance with the number of the year following the year of release of the next anti-virus version"). Initially, in the early 1990s, it was called -V, then - AntiViral Toolkit Pro.

1C: Enterprise is a system of programs for automating various areas of economic activity. A specific software product included in the 1C: Enterprise program system includes those functions and capabilities that meet the purpose of this product.

All components of the 1C: Enterprise program system can be divided into the Technological Platform and Configurations. The technological platform is a set of various mechanisms used to automate economic activity and is independent of specific legislation and accounting methodology. Configurations are actually applied solutions. Each configuration is focused on the automation of a certain area of ​​economic activity and, of course, complies with the current legislation.

"1C: Trade and Warehouse" is designed to account for any type of trading operations. Thanks to its flexibility and customizability, the system is able to perform all accounting functions - from maintaining directories and entering primary documents to receiving various statements and analytical reports.

"1C: Trade and Warehouse" automates work at all stages of the enterprise and allows you to:

• keep separate management and financial records
• keep records on behalf of several legal entities
• keep batch accounting of inventory with the ability to choose the method of writing off the cost (FIFO, LIFO, average)
• keep separate records of own goods and goods taken for sale
• handle the purchase and sale of goods
• perform automatic initial filling of documents based on previously entered data
• keep records of mutual settlements with buyers and suppliers, detail mutual settlements under individual agreements
• generate the necessary primary documents
• draw up invoices, automatically build a sales book and a purchase book, keep quantitative records in the context of customs declaration numbers
• perform product reservation and payment control
• keep a record of cash in current accounts and at the cash desk
• keep records of commodity loans and control their repayment
• keep records of goods transferred for sale, their return and payment

In "1C: Trade and Warehouse" you can:

• set the required number of prices of different types for each product, store supplier prices, automatically control and quickly change the price level
• work with related documents
• perform automatic calculation of write-off prices for goods
• quickly make changes using group processing of directories and documents
• keep records of goods in various units of measurement,
• and cash - in different currencies
• receive a wide variety of reporting and analytical information on the movement of goods and money
• automatically generate accounting entries for 1C: Accounting.

"1C: Trade and Warehouse" contains the means to ensure the safety and consistency of information:

• the ability to prohibit users from "direct" deletion of information
• special data deletion mode with cross-reference control
• the ability to prohibit users from editing data for past reporting periods
• setting a ban on editing printed forms of documents
• “locking” the system by the user during a temporary stoppage of work.

Server computer software

Windows 2000 Server is a feature-rich operating system that provides the functions of a file and print server, an application server, a Web server, and a communications server. The new system, compared to the previous one, provides greater reliability, speed and ease of management. More importantly, Windows 2000 Server has a large set of distributed services built on top of Active Directory, a multi-purpose, scalable Internet-based directory that is fully integrated with the system. Active Directory makes it much easier to administer systems and find resources in corporate network.

Numerous Web and Internet services included with Windows 2000 Server allow organizations to make extensive use of Internet technologies by building sophisticated Web applications and streaming services (audio, video, and so on) using Windows 2000 Server as the platforms for building intranet networks.

Windows 2000 Server is a promising target and tool platform for Independent Software Vendors (ISVs) and custom business application developers because it supports and evolves the most advanced distributed application services such as DCOM, transaction servers, and message queuing . In addition, to improve the performance of Windows 2000 Server, the base product in the Microsoft server family supports multi-processor symmetric processing (SMP) on two processors and up to 4 GB of memory.

1.4. Description of the activities of the information technology department of the organization

System Administrator Responsibilities:

1. Installs operating systems and software necessary for operation on servers and workstations.

2. Performs software configuration on servers and workstations.

3. Maintains the software of servers and workstations in working order.

4. Registers users of the local network and mail server, assigns identifiers and passwords

5. Provides technical and software support to users, advises users on the operation of the local network and programs, draws up instructions for working with the software and brings them to the attention of users.

6. Sets access rights and controls the use of network resources.

7. Provides timely copying, archiving and backup of data.

8. Takes measures to restore the operability of the local network in case of failures or failure of network equipment.

9. Identifies user and software errors and takes action to correct them.

10. Monitors the network, develops proposals for the development of the network infrastructure.

11. Provides network security (protection against unauthorized access to information, viewing or changing system files and data), security of internetworking.

12. Performs anti-virus protection of the local area network, servers and workstations.

13. Prepares proposals for upgrading and purchasing network equipment.

14. Controls the installation of local network equipment by third-party specialists.

15. Informs his immediate supervisor about cases of violation of the rules for using the local area network and the measures taken.

Chapter 2. Ensuring stable operation of computer systems and complexes

2.1. A list of instructions necessary for organizing the workplace of a computer systems adjuster or a hardware and software systems adjuster.

Hardware and software adjuster - a specialist who manages the operation of a computer and configures certain types of equipment related to computer technology and information support. The field of activity of this profession is the installation, maintenance and modernization of computer equipment, including hardware and software for personal computers, servers, as well as peripheral devices, equipment and computer office equipment.

Means of labor (the main types of equipment and technologies used)

– hardware and software of personal computers and servers;

- periphery equipment;

– multimedia equipment;

– informational resources local and global computer networks.

Main types of work (labor activities)

– maintenance of hardware for personal computers, servers, peripheral devices and equipment, computer office equipment;

– installation and maintenance of software for personal computers, servers, peripheral devices and equipment;

- modernization of hardware for personal computers, servers, peripherals and equipment;

– modernization of software for personal computers, servers, peripherals and equipment.

Professional competencies

– to put computer facilities into operation;

- to diagnose the health, troubleshoot and failures of hardware of computer equipment;

- replace consumables used in computing and office equipment;

– install operating systems on personal computers and servers, as well as configure the user interface;

– to administer operating systems of personal computers and servers;

- install and configure the operation of peripheral devices and equipment;

– install and configure application software for personal computers and servers;

- diagnose the health, troubleshoot and crash the operating system and application software;

– optimize the configuration of computer equipment depending on the requirements and tasks solved by the user;

- remove and add components of personal computers and servers, replace them with compatible ones;

- replace, remove and add the main components of peripheral devices, equipment and computer office equipment;

– update and delete versions of operating systems of personal computers and servers;

– update and delete versions of application software for personal computers and servers;

– update and remove device drivers for personal computers, servers, peripherals and equipment;

– update the firmware of computer components, servers, peripherals and equipment

2.2. Studying the system of preventive maintenance of computers in the organization

Safety requirements before starting work

• Put on and carefully tuck in special clothing (dressing gown) and technological footwear (slippers) established in accordance with current standards, avoiding hanging ends and constraint when moving.
• Check and verify the availability and serviceability of the fixed tool, devices to ensure safe work performance, personal protective equipment, fire extinguishing equipment.
• Check the condition of general and ordinary lighting.
• Do not carry out any work on the repair of fixtures, equipment, etc., if this is not part of the employee's responsibilities.
• Report all shortcomings and malfunctions found during the inspection at the workplace to the shift supervisor for taking measures to eliminate them completely.
• Place the tool in the workplace with maximum ease of use, avoiding the presence of unnecessary items in the work area.
• Check availability of first aid kit.

Safety requirements during work

• Work only in serviceable and carefully fitted overalls and special equipment. shoes and use personal protective equipment required at the workplace in accordance with current regulations.
• When servicing and repairing machines and equipment, the use of metal ladders is allowed. Work from boxes and other foreign objects is prohibited.
• It is necessary to install the stepladder firmly, checking its stability before lifting. Ladders with a height of 1.3 m or more must be equipped with a stop.
• Constantly monitor the health of the equipment. When leaving the machine or manipulator, the latter must be stopped and de-energized.
• Work in the presence and serviceability of fences, interlocks and other devices that ensure labor safety, with sufficient illumination.
• Do not touch moving mechanisms and rotating parts of machines, as well as energized live parts of equipment.
• Keep your work area tidy and clean.
• Keep foreign objects and tools away from moving mechanisms.
• When starting the machine, machine, personally make sure that there are no workers in the area of ​​the machines.
• All repair work on electrical installations, routine inspection, repairs should be carried out with the fuses (voltage) removed. Check the absence of voltage on current-carrying parts of electrical equipment with a voltmeter or voltage indicator.
• To protect against burns when changing lamps in the equipment, the service technician must use cotton gloves, special keys and fixtures.
• Immediately after carrying out the necessary shutdowns on the switching equipment (automatic device, knife switch, switch) disconnected during the preparation of the workplace, posters should be posted: “Do not turn on - people work!”, And disconnected for admission to work on overhead lines and cable lines - posters: “Do not turn on - work on the line!
• For work, use a hand tool with insulating handles (pliers, pliers, wire cutters, screwdrivers), the dielectric coating should not be damaged and fit snugly to the handle.
• Elimination of damage and repairs on the equipment must be carried out when the voltage is completely removed from the equipment.
• The portable power tool used (soldering iron, step-down transformer) must be tested and have an inventory number, systematically and timely checked and repaired.

Safety requirements in emergency situations

• Each employee who discovers violations of the requirements of this instruction and labor protection rules or notices a malfunction of the equipment that poses a danger to people is obliged to report this to the immediate supervisor.
• In cases where a malfunction of the equipment poses a threatening danger to people or the equipment itself, the employee who discovered it is obliged to take measures to terminate the operation of the equipment, and then notify the immediate supervisor about this. Troubleshooting is carried out in compliance with safety requirements.
• If an accident occurs during work, it is necessary to immediately provide first aid to the victim, report the incident to your immediate supervisor and take measures to preserve the situation of the accident, if this is not associated with a danger to life and health of people.
• In case of electric shock, it is necessary to release the victim from the action of the current as soon as possible, in case of working at height, take measures to prevent him from falling. Switch off the equipment using switches, a plug-in connector, cut the supply wire with a tool with insulated handles. If it is impossible to turn off the equipment quickly enough, other measures must be taken to free the victim from the action of the current. To separate the victim from current-carrying parts or wires, use a stick, board or some other dry object that does not conduct electricity, while the caregiver must stand on a dry, non-conductive place, or wear dielectric gloves.
• If a fire occurs in a technical room, you should immediately start extinguishing it with the available means (carbon dioxide fire extinguishers, asbestos blankets, sand) and call the fire department.

Safety requirements at the end of work

• It is necessary to tidy up the workplace, tools and fixtures.
• Notify the work manager of any malfunctions noticed during work and the measures taken to eliminate them
• Put away the overalls in a specially designated place.

Studying the system of preventive maintenance of computers in the organization

Types of technical maintenance of SVT

The type of maintenance is determined by the frequency and complex of technological operations to maintain the operational properties of the SVT.

GOST 28470-90 "System for the maintenance and repair of technical means of computer technology and informatics" defines the following types of maintenance

• regulated;
• periodic;
• with periodic control;
• with continuous monitoring.

Scheduled maintenance should be carried out to the extent and taking into account the operating time provided for in the operational documentation for the SVT, regardless of the technical condition.

Periodic maintenance should be carried out at intervals and to the extent specified in the operational documentation for the SVT.

Maintenance with periodic monitoring should be carried out with the frequency of monitoring the technical condition of the computer and the necessary set of technological operations, depending on the technical condition of the computer, established in the technological documentation.

Maintenance with continuous monitoring should be carried out in accordance with the operational documentation for the SVT or technological documentation based on the results of continuous monitoring of the technical condition of the SVT.

Control of the technical condition of the SVT can be performed in static or dynamic modes.

In the static mode, the control values ​​of voltages and clock frequencies remain constant throughout the entire cycle of preventive control, and in the dynamic mode, their periodic change is provided. Thus, due to the creation of heavy operating modes of the SVT, it is possible to identify elements that are critical in terms of reliability.

Preventive control is carried out by hardware and software. Hardware control is carried out with the help of special equipment, instrumentation and stands, and software and hardware systems.

Troubleshooting activities during preventive control can be divided into the following stages:

• analysis of the nature of malfunctions according to the current state of the computer;
• control of environmental parameters and measures to eliminate their deviations;
• localization of the error and determination of the location of the malfunction with the help of hardware and software of the SVT and with the help of additional equipment;
• trouble-shooting;
• resuming the solution of the problem.

Currently, the following types of maintenance systems (STO) are most widely used:

• Scheduled preventive maintenance;
• Service according to technical condition;
• Combined service.

Scheduled preventive maintenance is based on the calendar principle and implements scheduled and periodic maintenance. These works are carried out in order to maintain the CVT devices in good condition, identify equipment failures, prevent failures and failures in the operation of the CVT.

The frequency of scheduled preventive maintenance depends on the type of SVT and operating conditions (number of shifts and load).

Advantages of the system - provides the highest availability of SVT.

Disadvantages of the system - requires large material and physical costs.

In general, the system includes the following types of maintenance (preventive maintenance):

• control examinations (KO)
• daily maintenance (ETO);
• weekly maintenance;
• two-week MOT;
• ten-day maintenance;
• monthly maintenance (TO1);
• two-month maintenance;
• semi-annual or seasonal (SRT);
• annual maintenance;

KO, ETO SVT includes inspection of devices, running a quick test of readiness (operability of devices), as well as work provided for by daily preventive maintenance (in accordance with the operating instructions) of all external devices (cleaning, lubrication, adjustment, etc.).

During the two-week maintenance, diagnostic tests are run, as well as all types of two-week preventive maintenance provided for external devices.

With monthly maintenance, it provides for a more complete check of the functioning of the computer with the help of the entire system of tests that are part of its software. The check is carried out at the nominal values ​​of the power sources with a preventive voltage change of + 5%.

Preventive voltage change allows you to identify the weakest circuits in the system. Typically, circuits must maintain their performance when the voltage changes within the specified limits. However, aging and other factors cause gradual changes in the performance of the circuits, which can be detected on prophylactic regimens.

CVT proactive voltage testing detects predictable faults, thereby reducing the number of hard-to-locate faults that lead to failures.

During the monthly preventive maintenance, all necessary work is carried out, provided for in the operating instructions for external devices.

With a semi-annual (annual) maintenance (SRT), the same work is carried out as with a monthly maintenance. As well as all types of semi-annual (annual) maintenance work: disassembly, cleaning and lubrication of all mechanical components of external devices with their simultaneous adjustment or replacement of parts. In addition, the cables and power busbars are inspected.

A detailed description of preventive maintenance is given in the operating instructions for individual devices attached to the SVT by the manufacturer.

When maintaining on a technical condition, the performance of maintenance work is unscheduled and is performed as necessary based on the state of the object (test results), which corresponds to maintenance with continuous monitoring or maintenance with periodic monitoring.

Unscheduled preventive maintenance includes extraordinary preventive maintenance, appointed mainly after the elimination of serious malfunctions of the computer. The scope of preventive measures is determined by the nature of the malfunction and its possible consequences.

The conclusion of the SVT for unscheduled preventive maintenance can also be carried out when the number of failures that occur over a certain set period of time exceeds the allowable values.

The system requires the presence and correct use of various testing tools (software).

The system allows minimizing the cost of operating the WTS, but the readiness of the WTS for use is lower than when using a planned preventive service station.

With a combined maintenance system, “junior types of maintenance” are carried out as necessary, as with maintenance on condition, based on the operating time and operating conditions of a particular type of computer equipment or the results of its testing. The implementation of "senior types of maintenance" and repairs is planned.

The rational organization of service stations should provide for the accumulation of static material based on the results of CVT operation in order to summarize, analyze and develop recommendations for improving the service structure, increasing the efficiency of using CVT, and reducing operating costs.

The list of necessary material and technical means for organizing and carrying out work on maintenance of the SVT

The quality of SVT operation depends on the provision of spare parts, various devices and consumables, the provision of instrumentation, tools, etc. It is also of great importance to create the necessary conditions for normal functioning computing facilities (temperature and humidity conditions, power supply, etc.) and for service personnel (climatic conditions, noise level, illumination, etc.).

The operation of the CVT must be carefully planned. Planning should cover the entire range of issues related both to the compilation of the general program of work of the CVT, the distribution of machine time, etc., and to the entire work of the maintenance personnel.

The rational organization of operation should provide for the accumulation of static material based on the results of the operation of the SVT in order to summarize, analyze and develop recommendations for improving the service structure, increasing the efficiency of using the SVT, and reducing operating costs.

Diagnostic programs

For PCs, there are several types of diagnostic programs (some of which are included with the computer) that allow the user to identify the causes of problems that occur in the computer. Diagnostic programs used in PCs can be divided into three levels:

• BIOS diagnostic programs - POST (Power-OnSelfTest - power-on self-test procedure). Runs every time the computer is turned on.
• The Windows operating system diagnostic programs come with several diagnostic programs to test various components of your computer.
• Diagnostic programs of firms - manufacturers of equipment.
• Diagnostic programs for general purposes. Such programs, which provide thorough testing of any PC-compatible computers, are produced by many companies.

Power-on Self Test (POST)

POST is a sequence of short routines stored in the ROM BIOS on the motherboard. They are designed to check the main components of the system immediately after it is turned on, which, in fact, is the reason for the delay before loading the operating system.

Each time you turn on your computer, it automatically checks its main components:

• processor,
• ROM chips,
• auxiliary elements of the system board,
• RAM and major peripherals.

These tests are fast and not very thorough when a faulty component is found, a warning or error message (failure) is issued. Such faults are sometimes referred to as fatal errors. The POST procedure usually provides three ways to indicate a malfunction:

• sound signals,
• messages displayed on the screen
• hexadecimal error codes issued to the I/O port.

When POST detects a problem, the computer emits distinctive beeps that can help identify the failed item (or group of items). If the computer is working properly, then when you turn it on, you will hear one short beep; if a malfunction is detected, a whole series of short or long beeps is issued, and sometimes a combination of them. The nature of the sound codes depends on the BIOS version and the company that developed it.

In most PC-compatible models, the POST procedure displays the progress of testing the computer's RAM on the screen. If an error is detected during the POST procedure, a corresponding message is displayed, usually in the form of a numerical code of several digits, for example: 1790- Disk 0 Error. By using the instruction manual and after-sales service, you can determine which fault corresponds to this code. Error codes issued by POST to I/O ports

A lesser known feature of this procedure is that at the beginning of each test, POST outputs test codes to a special I/O port address, which can only be read using a special adapter card installed in the expansion slot. The POST board is installed in the expansion slot. At the time of the POST procedure, its built-in indicator will rapidly change two-digit hexadecimal numbers. If the computer unexpectedly stops testing or “freezes”, this indicator will display the code of the test during which the failure occurred. This allows you to significantly narrow the search for a faulty element. On most computers, POST codes to I/O port 80h

Operating system diagnostic programs

DOS and Windows include several diagnostic programs. that provide testing constituent parts SVT. Modern diagnostic programs have graphical shells and are part of the operating system. Such programs are, for example:

• utility to clean the disk from unnecessary files;
• utility to check the disk for errors;
• utility for defragmenting files and free space;
• data archiving utility;
• file system conversion utility.

All of these programs are also available in Windows.

Diagnostic programs of equipment manufacturers

Equipment manufacturers produce special specialized programs for diagnosing specific equipment, a specific manufacturer. The following groups of programs can be distinguished:

• Hardware Diagnostic Programs
• SCSI Device Diagnostic Programs
• Network adapter diagnostic programs

Diagnostic programs for general and special purposes

Most test programs can be run in batch mode, which allows you to run a whole series of tests without operator intervention. You can create an automated diagnostic program that is most effective if you need to identify possible defects or run the same sequence of tests on multiple computers.

These programs check all types of system memory: basic (base), extended (expanded) and additional (extended). The location of the fault can often be determined down to a single chip or module (SIMM or DIMM)

There are many such programs. This type of software can be divided into the following categories:

• Information programs;
• Test programs;
• Universal programs

Information programs

They are used in situations where it is necessary to find out a detailed configuration and test the computer for maximum performance without disassembling the system unit or when, at first glance, everything works fine, but the user claims that his computer is constantly buggy and starts up every other time. Or after a repair, such as replacing the electrolytic capacitors on the motherboard, a thorough diagnostic is required to make sure that the computer is working properly. They test a computer or individual components, and provide detailed information about its condition, functionality, and possible software and physical problems.

Test programs

They work on the principle of maximum load with various operations that emulate the work of a user at a computer, and measure overall performance system or the performance of individual components based on a comparison, with an already existing database.

Universal programs

Programs combining two categories of programs - informational and test. They allow not only to test the PC, but also to obtain comprehensive information about its components.

There are several completely different versions of the program, but they are all focused solely on measuring the performance of a video system.

When you start the program, in the main window you will see only the model of the video card and the characteristics of the monitor. For more information, click on SystemInfo, there you can find out - processor model, cache memory size, directX version and other system information. It is possible to select all or only some tests in the program. Almost all tests are run twice, at low and high detail, which gives greater accuracy. After the test, the program displays the result in the form of points that can be compared with another computer. The main thing is that the video system test is not complete without a critical load on other computer components. And if the computer under test coped with them, then most likely the main components are in order.

Among the packages of service utilities, without a doubt, "the first among equals" is NortonUtilities manufactured by Symantec and has already grown to the 2001 version.

The included SystemInformation utility provides conveniently grouped information on all major computer components. It is possible to detail information on some sections, as well as generate a report. Quite clearly and colorfully, with the use of pie charts, information about the efficiency and use of the disk is framed. You can test the processor by clicking the Benchmark button. The program gives a graph of the approximate speed of your system, the unit of measurement is the performance of a PC based on an Intel 386SX-16MHz processor.

Service equipment

To troubleshoot and repair a PC, you need special tools that allow you to identify problems and fix them simply and quickly.

These include:

• a set of tools for disassembly and assembly;
• chemicals (solution for wiping contacts), a spray bottle with coolant and a can of compressed gas (air) for cleaning computer parts;
• a set of swabs for wiping contacts;
• specialized improvised tools (for example, tools needed to replace microcircuits (chips));
• service equipment.

Service equipment is a set of devices designed specifically for diagnosing, testing and repairing computer hardware. Service equipment includes the following elements:

• Measuring instruments test connectors for testing serial and parallel ports;
• memory testing devices that allow you to evaluate the functioning of SIMM modules, DIP chips and other memory modules;
• equipment for testing a computer power supply;
• diagnostic devices and programs for testing computer components (hardware and software systems).

Measuring instruments and test sockets for testing PC ports

The following measuring instruments are used to check and repair a PC:

• digital multimeter;
• logic probes;
• single pulse generators for testing digital circuits.

Test connectors provide software and hardware testing of PC I/O ports (parallel and serial).

Computer power supply testing equipment provides testing of PC power supplies and determination of their main characteristics. It is a set of equivalent loads, switching elements and measuring instruments.

2.3. Description of monitoring, diagnostics and recovery of computer systems and complexes

Status analysis and troubleshooting "SamsungML-1210"

The printer does not pick up paper. The problem is in the capture roller. You need to do preventive maintenance.

Technical description "SamsungML-1210"

Main characteristics:

• Printing technology - laser (Electrography);
• Print speed - 12 PPM (pages per minute);
• Toner saving mode up to 30%;
• Resolution - 600 × 600 dpi;
• Powerful 66 MHz processor;
• Repeat the printing of the last sheet by pressing one button;
• Compatibility (Linux, Macintosh, Windows).

Other Features:

• Tray (cassette) - 150 sheets;
• Output tray - 100 sheets;
• Paper size - Letter, legal, Monarch, com 10, C5, DL, A4, A5, B5;
• Interface - USB, IEEE 1284 (parallel);
• Processor - 66 MHz;
• Memory (MB) - 8 MB;
• Working cycle (pages per month) - 12000;
• Supported operating systems - Windows 95/98/2000/Me/NT, Linux (Redhat 6.0), Macintosh OS 8.0 and later;
• Emulation - Smart GDI;
• Toner cartridge - Single cartridge: 2500 pages at 5% coverage, 1000 starter.
• Power consumption (W):
• Standby - 5;
• In print mode - 180;
• Warm-up time (sec.) - 25;
• First page output (sec.) - 13;
• Noise level (max., dB) - 47;
• Fonts - Windows fonts;
• Size (W × D × H) mm - 329 × 355 × 231;
• Printer weight - 6.2 kg.

Troubleshooting and failures "SamsungML-1210"

The front cover opens, 2 screws are unscrewed.

Unscrew 4 screws on the back.

The back wall, the top cover is removed, the paper guides are taken out and the side walls are removed.

Unscrew 3 screws that hold the laser. Disconnect 2 connectors located on the sides. The glass is wiped with a cotton swab or a clean piece of cloth.

The gripper roller, which is held by 2 self-tapping screws, is actually unscrewed and cleaned with a special liquid. At the same time, the brake pad is cleaned. It is located in the machine under the pickup roller.

Then the printer itself is cleaned. This operation can be performed with a vacuum cleaner or a compressor.

Assembly is carried out in the reverse order.

2.4. Identification of the shortcomings of the system for ensuring the stable operation of computer systems and complexes. Suggestions for improving this system

The disadvantage of this organization is the lack of a maintenance schedule for PCs and peripheral equipment. In this regard, this schedule was proposed and developed.

Chapter 3. Description of the information system used in the organization

3.1 Analysis subject area for information system

Students organized in groups study in one of the specialties. Teachers are involved in the learning process. The educational process is regulated by the curriculum, indicating the number of hours for each discipline and the form of control (test, exam). A teacher can lead classes in one or more disciplines.

3.2 Analysis/development of the structure of the information system

This figure shows structural scheme program execution, which means that information is taken from directories into the document.

A use case diagram (use case diagram) in UML is a diagram that reflects the relationship between actors and use cases and is an integral part of the use case model that allows you to describe the system at a conceptual level.

Precedent - the possibility of a simulated system (part of its functionality), thanks to which the user can get a specific, measurable and desired result. A use case corresponds to a particular service of the system, defines one of the options for its use, and describes a typical way of user interaction with the system. Use cases are typically used to specify external requirements for a system. .

3.3 Description of the database management system/software used for development

The 1C: Enterprise 8 software system includes a platform and application solutions developed on its basis for automating the activities of organizations and individuals. The platform itself is not a software product for use by end users who typically work with one of many applied solutions(configurations) developed on this platform. This approach allows you to automate different kinds activities using a single technological platform.

3.4. Instructions for users to work with the information system

3.4.1 Purpose of the program

The program allows:

• based on the entered data allows you to view the information of interest.
• to carry out automated selection of the necessary information.
• generate and print documents for registration and reporting forms.

program benefits « information system of the auto enterprise ":

• convenience and ease of use;
• small amount of occupied memory on hdd;
• operational service.

Functional purpose

• the ability to independently manage the accounting methodology as part of setting up accounting policies and setting accounting parameters;
• arbitrary structure of the account code makes it possible to use long codes of accounts (sub-accounts) and maintain multi-level charts of accounts with a large nesting level;
• the ability to work with several charts of accounts allows you to keep records in several accounting systems;
• contains built-in mechanisms for conducting quantitative and currency accounting;
• on any account, you can maintain multidimensional and multilevel analytical accounting;
• the user can independently create new types of subconto, add accounts and subaccounts;
• business transactions are reflected in accounting mainly by entering configuration documents that are identical to primary accounting documents, it is possible to enter individual entries manually;
• when reflecting business transactions in configuration documents, you can explicitly indicate accounting and tax accounts;
• the applied accounting methodology ensures the simultaneous registration of each record of a business transaction, both according to accounting accounts and according to the necessary sections of analytical accounting, quantitative and currency accounting;

Operational purpose

The program should be operated by enterprises focused on the automotive industry, namely passenger and freight transport.

Users of the program must be employees of the automotive industry.

Composition of functions

The program provides the ability to perform the following functions:

• functions for creating a new (empty) file;
• functions for opening (loading) an existing file;
• inventory accounting;
• inventory control;
• accounting of trade operations;
• accounting of commission trade;
• accounting of agency contracts;
• accounting of operations with containers;
• accounting of banking and cash transactions;
• accounting for settlements with counterparties;
• accounting of fixed assets and intangible assets;
• accounting of the main and auxiliary production;
• accounting of semi-finished products;
• accounting for indirect costs;
• VAT accounting;
• payroll accounting, personnel and personalized accounting;
• income tax accounting;
• simplified taxation system;
• accounting for activities subject to a single tax on imputed income;
• accounting of income and expenses of individual entrepreneurs - payers of personal income tax;

3.4.2 Program execution conditions

Climatic operating conditions under which the specified characteristics must be ensured must meet the requirements for technical equipment in terms of their operating conditions.

Minimum composition of technical means

The hardware should include an IBM-compatible personal computer (PC), which includes:

• processor Pentium-1000 with a clock frequency, GHz - 10, not less;
• motherboard with FSB, GHz - 5, not less;
• RAM volume, GB - 2, not less;

Minimum composition of software

The system software used by the program must be represented by a licensed localized version of the operating system. You can use update package 8.3.5.1284.

3.4.3 Program execution

Program launch

The program is launched by double-clicking the left mouse button on the label of the program "1C: Enterprise 8.3", then you need to select the "WIS Base" configuration and click the "Configurator" item. The selection window is shown in Figure 1.

Figure 1 - Launching the infobase

After launching the program module in the "1C: Enterprise 8.3" system, the "Working window of the 1C: Enterprise 8.3 system" will appear on the screen, it displays a menu and a toolbar in accordance with the selected user, it looks like this: the working window of the system is shown in Figure 2 .

Figure 2 - Appearance of the configuration menu

Menu operation

This menu can be divided into:

• menu "File";
• menu "Edit";
• menu "Configuration";
• menu "Debug";
• menu "Administration",
• menu "Service",
• menu "Windows",
• Help menu

You can choose the basic actions for editing and setting up a document, from creating and saving a new document to setting access rights to the infobase. You can also customize the interface for a specific user, use the help offered by the program to facilitate work.

The main menu is the "Configuration" menu, because the structure of the infobase is created in it. Each configuration object has a unique set of properties. This set is described at the system level and cannot be changed during task configuration. The set of properties of a configuration object is determined mainly by its purpose in the 1C:Enterprise system.

The main property of any configuration object is the name - the short name of the configuration object. When a new configuration object is created, it is automatically assigned a conditional name consisting of a word determined by the type of object and a number. This name can be changed while editing the properties of the configuration object, while the system keeps track of the uniqueness of the names. The configuration object name cannot be empty and cannot be longer than 255 characters.

Some properties from the entire set of properties inherent in the configuration object are available for editing and can be changed in one way or another during the system configuration. The nature of the changes and their limits are also set at the system level. A specialist who configures the system can achieve the desired behavior of the object during system operation by purposefully changing the properties of the configuration object.

3.4.4 Operator messages

Since the program is not a console (with a command line interface), but with a graphical user interface, classical text messages not expected. Error messages are displayed as windows on the desktop. Shown in Figure 3.

3.5 Description of means, methods of information protection when working with an information system

1C:Enterprise supports the ability to upload/download an infobase to a file. This mechanism is intended primarily for obtaining an infobase image, regardless of how data is stored. For example, loading/unloading an infobase to a file can be used to convert the file version to a client-server one.

Sometimes this mode is also used to create backup information base, but this variant of its use has a number of disadvantages. The main disadvantage of this method of creating a backup is the need to use single-user mode to carry out this operation. With a large amount of information base, a break in the work of users can be quite large, which is not always acceptable.

Depending on the variant of 1C: Enterprise (file or client-server), we can recommend the following ways to create a backup copy of the infobase:

1) When using the 1C:Enterprise 8 file option, you can organize the process of creating an infobase backup copy by simply copying the 1CV8.1CD file to a separate directory or using data backup and recovery software. It should be taken into account that to ensure the integrity and consistency of data during the creation of a backup, the work of users with the infobase should be prohibited, however, the time required to create a backup is significantly less than when using uploading the infobase to a file.

2) When using the client-server version of 1C: Enterprise 8, it becomes possible to create a backup copy of the infobase using the DBMS. For example, SQL Server allows data to be backed up while the database is in multi-user mode and available to all users.

Using these methods gives the most accurate copy of the infobase state, which cannot always be obtained when using the infobase loading/unloading mode. For example, if the database is corrupted, then unloading some information may not be unloaded, while copying will preserve all the information, and after restoration, you can perform a database repair.

The time spent by the infobase in single-user mode is also significantly reduced in the case of the file version of 1C: Enterprise 8, and in the case of the client-server version, single-user mode is not used at all.

In addition, the positive point is that when using the above methods, you can use various specialized software tools to create backups.

Conclusion

During the internship in the direction 230000 Informatics and Computer Engineering in the specialty 230113 Computer Systems and Complexes, the following tasks were performed:

Formation and development of general and professional competencies in the field of the chosen specialty;

Acquisition and formation necessary skills, skills and experience of practical work for solving professional problems in the conditions of a particular enterprise (organization) of the city and district;

• Organization of independent professional activity, socialization in a specific type of activity.
• Also, as a result of practical training in the direction 230000 Informatics and Computer Engineering in the specialty 230113 Computer Systems and Complexes, the following tasks were completed:
• Consolidation, deepening and expansion of the acquired theoretical knowledge, skills and abilities;
• Mastering professional competencies, production skills and new methods of work;
• Mastering the norms of the profession in the motivational sphere: awareness of motives and spiritual values ​​in the chosen profession;
• Mastering the basics of the profession in the operational sphere: familiarization and assimilation of the methodology for solving professional tasks (problems);
• The study of different aspects of professional activity: social, legal, psychological, hygienic, technical, technological, economic.

As a result of practical training, experience was gained in supporting workstations in working order, as well as in analyzing and structuring knowledge about the information system of the branch.

List of sources used

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9. Radchenko M.G. 1C:Enterprise 8.0. Practical developer guide. Examples and typical techniques. [Text] / M.:, 1C-Publishing LLC, 2004. -656 p.: ill.
10. Radchenko M.G. Repair of computers and peripherals. [Text] / M.:, 1C-Publishing LLC, St. Petersburg: Peter, 2007. -512 p.: ill.
11. Russian State Library [Electronic resource] / Center inform. RSL technologies; ed. Vlasenko T.V.; Web-master Kozlova N.V. - Electron, yes. – M. : Ros. state library, 1997 . – Access mode: http://www.rsl.ru, free

Content

Introduction

Chapter 1 Concept and classification of computer networks

1.1 Purpose of a computer network

1.2 Classification of computer networks

Chapter 2. Main types of computer networks

2.1 Local area network (LAN)

2.2 Wide Area Network (WAN)

Conclusion

List of used literature

Introduction

Russia's entry into the world informational space entails the widest use of the latest information technologies, and in the first place, computer networks. At the same time, the user's capabilities sharply increase and change qualitatively both in providing services to their customers and in solving their own organizational and economic problems.

It is appropriate to note that modern computer networks are a system whose capabilities and characteristics as a whole significantly exceed the corresponding indicators of a simple sum of the constituent elements of a personal computer network in the absence of interaction between them.

The advantages of computer networks have led to their widespread use in information systems of the credit and financial sector, government bodies and local self-government, enterprises and organizations.

Computer networks and network information processing technologies have become the basis for building modern information systems. The computer should now be considered not as a separate processing device, but as a "window" into computer networks, a means of communication with network resources and other network users.

In recent years, the global Internet has become a global phenomenon. The network, which until recently was used by a limited circle of scientists, civil servants and employees of educational institutions in their professional activities, has become available to large and small corporations and even to individual users.

The purpose of this course work is to get acquainted with the basics of building and functioning computer networks, studying the organization of computer networks. To achieve this goal, it is necessary to solve a number of tasks:

Acquaintance with computer networks, highlighting their features and differences;

Characteristics of the main methods of building networks (network topology);

The study of scientific and methodological literature on this issue

Chapter 1 Concept and classification of computer networks

1.1 Purpose of a computer network

The main purpose of computer networks is the sharing of resources and the implementation of interactive communication both within one company and outside it. Resources are data, applications, and peripherals such as an external drive, printer, mouse, modem, or joystick.

Computers included in the network perform the following functions:

Organization of access to the network

Transfer control

Provision of computing resources and services to network users.

Currently, local area computing (LAN) is very widespread. This is due to several reasons:

Combining computers into a network allows you to significantly save money by reducing the cost of maintaining computers (it is enough to have a certain disk space on the file server (main computer of the network) with software products installed on it and used by several workstations);

Local networks allow you to use a mailbox to send messages to other computers, which allows you to transfer documents from one computer to another in the shortest possible time;

Local networks, in the presence of special software (software), serve to organize the sharing of files (for example, accountants on several machines can process the entries of the same ledger).

Among other things, in some areas of activity it is simply impossible to do without a LAN. These areas include: banking, warehouse operations of large companies, electronic archives of libraries, etc. In these areas, each individual workstation, in principle, cannot store all information (mainly due to its too large volume).

Global Computing Network - a network that connects computers that are geographically distant at great distances from each other. It differs from a local network in more extensive communications (satellite, cable, etc.). The global network unites local networks.

The global Internet, which once served exclusively research and educational groups, whose interests extended to access to supercomputers, is becoming increasingly popular in the business world.

1.2 Classification of computer networks

According to the method of organization, networks are divided into real and artificial.

Artificial networks (pseudo-networks) allow computers to be linked together via serial or parallel ports and do not require additional devices. Sometimes communication on such a network is referred to as null-modem communication (no modem is used). Self-connection is called null-modem. Artificial networks are used when it is necessary to transfer information from one computer to another. MS-DOS and windows are equipped with special programs to implement a null modem connection.

Real networks allow you to connect computers using special switching devices and a physical data transmission medium.

/> Territorial distribution of networks can be local, global, regional and urban.

A local area network (LAN) - Local Area Networks (LAN) is a group (communication system) of a relatively small number of computers, united by a shared data transmission medium, located on a limited small area within one or more closely located buildings (usually within a radius of no more than 1 -2 km) in order to share the resources of all computers

Global Area Network (WAN or WAN - World Area NetWork) - a network that connects computers that are geographically distant over long distances from each other. It differs from a local network in more extended communications (satellite, cable, etc.). The global network unites local networks.

Metropolitan Area NetWork (MAN - Metropolitan Area NetWork) - a network that serves the information needs of a large city.

Regional - located on the territory of the city or region.

Also, recently, experts have identified such a type of network as a banking one, which is a special case of a corporate network of a large company. Obviously, the specifics of banking activities impose strict requirements on information security systems in the bank's computer networks. An equally important role in building a corporate network is played by the need to ensure trouble-free and uninterrupted operation, since even a short-term failure in its operation can lead to huge losses.

By affiliation, departmental and state networks are distinguished. Departmental ones belong to one organization and are located on its territory.

State networks - networks used in government structures.

According to the speed of information transfer, computer networks are divided into low-, medium- and high-speed.

low-speed (up to 10Mbps),

medium-speed (up to 100Mbps),

high-speed (over 100 Mbps);

Depending on the purpose and technical solutions, networks can have different configurations (or, as they say, architecture or topology).

In a ring topology, information is transmitted over a closed channel. Each subscriber is directly connected to two nearest neighbors, although in principle it is able to communicate with any subscriber in the network.

In the star-shaped (radial) in the center there is a central control computer that communicates in series with subscribers and connects them with each other.

In a bus configuration, computers are connected to a common channel (bus) through which they can exchange messages.

In a tree-like one, there is a “master” computer, to which computers of the next level are subordinate, and so on.

In addition, configurations without a distinct nature of the connections are possible; the limit is a fully meshed configuration, where every computer on the network is directly connected to every other computer.

From the point of view of organizing the interaction of computers, networks are divided into peer-to-peer (Peer-to-Peer Network) and a dedicated server (Dedicated Server Network).

All computers in a peer-to-peer network are equal. Any network user can access data stored on any computer.

Peer-to-peer networks can be organized using operating systems such as LANtastic, windows "3.11, Novell Netware Lite. These programs work with both DOS and Windows. Peer-to-peer networks can also be organized based on all modern 32-bit operating systems - Windows 9x \ME\2k, Windows NTworkstation version, OS/2) and some others.

Advantages of peer-to-peer networks:

1) the most easy to install and operate.

2) DOS and Windows operating systems have all the necessary functions to build a peer-to-peer network.

The disadvantage of peer-to-peer networks is that it is difficult to solve information security issues. Therefore, this method of organizing a network is used for networks with a small number of computers and where the issue of data protection is not fundamental.

In a hierarchical network, when the network is set up, one or more computers are pre-allocated to manage network communication and resource allocation. Such a computer is called a server.

Any computer that has access to server services is called a network client or workstation.

A server in hierarchical networks is a persistent store of shared resources. The server itself can only be a client of the server more high level hierarchy. Therefore, hierarchical networks are sometimes referred to as dedicated server networks.

Servers are usually high-performance computers, possibly with several processors working in parallel, with high-capacity hard drives, with a high-speed network card (100 Mbps or more).

The hierarchical network model is the most preferable, as it allows creating the most stable network structure and more rationally allocating resources.

Also, the advantage of a hierarchical network is a higher level of data protection.

The disadvantages of a hierarchical network, compared to peer-to-peer networks, include:

1) the need for an additional OS for the server.

2) higher complexity of network installation and upgrade.

3) The need to allocate a separate computer as a server.

Chapter 2 Main Types of Computing Networks

2.1 Local area network (LAN)

Local area networks (LAN computers) unite a relatively small number of computers (usually from 10 to 100, although occasionally much larger ones) within the same room (training computer class), building or institution (for example, a university). The traditional name is a local area network (LAN). ) - rather a tribute to the times when networks were mainly used and solving computational problems; today, in 99% of cases, we are talking exclusively about the exchange of information in the form of texts, graphic and video images, and numerical arrays. The usefulness of LS is explained by the fact that from 60% to 90% of the information necessary for an institution circulates inside it, without needing to go outside.

The creation of automated enterprise management systems (ACS) had a great influence on the development of drugs. ACS includes several automated workstations (AWP), measuring complexes, control points. Another important field of activity in which drugs have proved their effectiveness is the creation of classes of educational computer technology (KUVT).

Due to the relatively short lengths of communication lines (as a rule, no more than 300 meters), information can be transmitted via LAN in digital form at a high transmission rate. Over long distances, this transmission method is unacceptable due to the inevitable attenuation of high-frequency signals, in these cases it is necessary to resort to additional technical (digital-to-analog conversions) and software (error correction protocols, etc.) solutions.

A characteristic feature of the LS is the presence of a high-speed communication channel connecting all subscribers to transmit information in digital form.

There are wired and wireless channels. Each of them is characterized by certain values ​​of parameters that are essential from the point of view of the organization of the LAN:

Data transfer rates;

Maximum line length;

Noise immunity;

Mechanical strength;

Convenience and ease of installation;

Costs.

Currently, four types of network cables are commonly used:

Coaxial cable;

Unprotected twisted pair;

Protected twisted pair;

Fiber optic cable.

The first three types of cables transmit an electrical signal over copper conductors. Fiber optic cables transmit light over glass fiber.

Most networks allow for multiple cabling options.

Coaxial cables consist of two conductors surrounded by insulating layers. The first layer of insulation surrounds the central copper wire. This layer is braided on the outside with an external shielding conductor. The most common coaxial cables are thick and thin Ethernet cables. This design provides good noise immunity and low signal attenuation over distances.

There are thick (about 10 mm in diameter) and thin (about 4 mm) coaxial cables. With advantages in noise immunity, strength, league length, a thick coaxial cable is more expensive and more difficult to install (it is more difficult to pull through cable channels) than a thin one. Until recently, a thin coaxial cable was a reasonable compromise between the main parameters of LAN communication lines and in Russian conditions is most often used to organize large LAN enterprises and institutions. However, thicker, more expensive cables provide better data transmission over longer distances and are less susceptible to electromagnetic interference.

Twisted-pair cables are two wires twisted together at six turns per inch to provide EMI protection and conductance or electrical resistance matching. Another name commonly used for such a wire is "IBM type-3". In the US, such cables are installed during the construction of buildings to provide telephone communications. However, the use of telephone wire, especially when it is already placed in a building, can create great problems. First, unprotected twisted pairs are susceptible to electromagnetic interference, such as electrical noise generated by fluorescent lights and moving elevators. telephone lines along the LAN cable. In addition, poor quality twisted pairs may have a variable number of turns per inch, which distorts the calculated electrical resistance.

It is also important to note that telephone wires are not always laid in a straight line. A cable connecting two adjacent rooms can actually go around half the building. Underestimating the length of the cable in this case may result in it actually exceeding the maximum allowable length.

Shielded twisted pairs are similar to unprotected twisted pairs, except that they use thicker wires and are protected from the external impact of the insulator neck. The most common type of such cable used in local area networks, "IBM type-1" is a protected cable with two twisted pairs of continuous wire. In new buildings, type-2 cable may be the best option, as it includes, in addition to the data line, four unprotected pairs of continuous wire for transmission telephone conversations. Thus, "type-2" allows you to use one cable to transmit both telephone conversations and data over the local network.

The protection and careful adherence to the number of twists per inch make protected twisted-pair cable a reliable alternative to cabling.” However, this reliability comes at a cost.

Fiber optic cables transmit data in the form of "light pulses" to glass "wires". Most LAN systems currently support fiber optic cabling. Fiber optic cable has significant advantages over any copper cable options. Fiber optic cables provide the highest transmission speed; they are more reliable, as they are not subject to losses information packages due to electromagnetic interference. Optical cable is very thin and flexible, making it easier to transport than heavier copper cable. Most importantly, however, optical cable alone has the bandwidth that faster networks will require in the future.

For the time being, the price of fiber-optic cable is much higher than that of copper. Compared to a copper cable, the installation of an optical cable is more laborious, since its ends must be carefully polished and aligned to ensure a reliable connection. However, now there is a transition to fiber optic lines that are absolutely immune to interference and are out of competition in terms of bandwidth. The cost of such lines is steadily decreasing, technological difficulties splices of optical fibers are successfully overcome.

Wireless communication on microwave radio waves can be used to organize networks within large premises such as hangars or pavilions, where the use of conventional communication lines is difficult or impractical. In addition, wireless lines can connect remote segments of local networks at distances of 3 - 5 km (with a wave channel antenna) and 25 km (with a directional parabolic antenna) under the condition of direct visibility. Organization of a wireless network is significantly more expensive than usual.

Network adapters (or, as they are sometimes called, network cards) are required to connect computers using LAN links. The most famous are: adapters of the following three types:

Of these, the latter received overwhelming distribution in Russia. The network adapter is inserted directly into a free slot on the motherboard of a personal computer and to it on the rear panel. system block the LAN communication line is docked. The adapter, depending on its type, implements one or another access strategy from one computer to another.

To ensure consistent operation in data networks, various data communication protocols are used - sets of rules that the transmitting and receiving parties must adhere to for consistent data exchange. Protocols are sets of rules and procedures that govern how some communication takes place. Protocols are the rules and technical procedures that allow multiple computers to communicate with each other when connected to a network.

There are many protocols. And although they all participate in the implementation of communication, each protocol has different goals, performs different tasks, has its own advantages and limitations.

Protocols operate at different levels of the OSI/ISO Open Systems Interconnection model. The functions of protocols are determined by the layer at which it operates. Several protocols can work together. This is the so-called stack, or set, of protocols.

Just as network functions are distributed across all layers of the OSI model, so protocols work together at different layers of the protocol stack. The layers in the protocol stack correspond to the layers of the OSI model. Taken together, the protocols provide a complete description of the functions and capabilities of the stack.

Data transmission over a network, from a technical point of view, should consist of successive steps, each of which has its own procedures or protocol. Thus, a strict sequence is maintained in the performance of certain actions.

In addition, all of these steps must be performed in the same sequence on each networked computer. On the sending computer, actions are performed from top to bottom, and on the receiving computer, from bottom to top.

The sending computer, in accordance with the protocol, performs the following actions: breaks the data into small blocks, called packets, with which the protocol can work, adds address information to the packets so that the receiving computer can determine that this data is intended for it, prepares the data for transmission through the network adapter card and then through the network cable.

The recipient computer, in accordance with the protocol, performs the same actions, but only in the reverse order: it receives data packets from a network cable; through the network adapter card transfers data to the computer; removes from the package all the service information added by the sending computer, copies the data from the package to the buffer - to combine them into the original block, transfers this data block to the application in the format that it uses.

Both the sending computer and the receiving computer need to perform each action in the same way so that the data that arrives over the network matches the data that was sent.

If, for example, two protocols break data into packets and add information (packet sequencing, synchronization, and error checking) differently, then a computer running one of these protocols will not be able to successfully communicate with a computer running the other protocol.

Until the mid-1980s, most local area networks were isolated. They served individual companies and rarely combined into large systems. However, when local networks reached a high level of development and the volume of information transmitted by them increased, they became components of large networks. Data that travels from one local area network to another over one of the possible routes is called routed. Protocols that support the transfer of data between networks over multiple routes are called routed protocols.

Among the many protocols, the following are the most common:

· IPX/SPX and NWLmk;

The OSI protocol suite.

2.2 Wide Area Network (WAN)

WAN (World Area Network) is a global network covering large geographic regions, including both local area networks and other telecommunication networks and devices. An example of a WAN is a packet-switched network (Frame relay), through which various computer networks can “talk” to each other.

Today, when the geographic boundaries of networks are expanding to connect users from different cities and states, LANs are turning into a global area network [WAN], and the number of computers on the network can already vary from ten to several thousand.

Internet is a global computer network covering the whole world. Today, the Internet has about 15 million subscribers in more than 150 countries around the world. The size of the network increases by 7-10% monthly. The Internet forms, as it were, the core that provides communication between various information networks belonging to various institutions around the world, one with the other.

If earlier the network was used exclusively as a medium for transferring files and e-mail messages, then today more complex tasks of distributed access to resources are being solved. About three years ago, shells were created that support the functions of network search and access to distributed information resources, electronic archives.

The Internet, once exclusively for research and academic groups whose interests ranged from access to supercomputers, is becoming increasingly popular in the business world.

Companies are enticed by speed, cheap global connectivity, ease of collaboration, affordable software, and the unique database of the Internet. They see the global network as an addition to their own local networks.

At a low cost (often only a flat monthly fee for the lines or telephone used), users can access commercial and non-commercial information services in the US, Canada, Australia, and many European countries. In the archives of free access to the Internet, you can find information on almost all areas of human activity, starting with new scientific discoveries and forecasting the weather for tomorrow.

In addition, the Internet provides a unique opportunity for cheap, reliable and private global communications around the world. It turns out to be very convenient for companies with their branches around the world, multinational corporations and management structures. Usually, using the Internet infrastructure for international communication is much cheaper than direct computer communication via satellite or telephone.

E-mail is the most common service on the Internet. Approximately 20 million people currently have their email address. Sending a letter by e-mail is much cheaper than sending a regular letter. In addition, a message sent by e-mail will reach the addressee in a few hours, while a regular letter can reach the addressee for several days or even weeks.

Currently, the Internet uses almost all known communication lines from low-speed telephone lines to high-speed digital satellite channels.

In fact, the Internet consists of many local and global networks belonging to various companies and enterprises, interconnected by various communication lines. The Internet can be imagined as a mosaic of small networks of various sizes that actively interact with each other, sending files, messages, etc.

As in any other network on the Internet, there are 7 levels of interaction between computers: physical, logical, network, transport, session level, presentation and application level. Accordingly, each level of interaction corresponds to a set of protocols (i.e. rules of interaction).

Physical layer protocols define the type and characteristics of communication lines between computers. The Internet uses almost all currently known communication methods, from a simple wire (twisted pair) to fiber-optic communication lines (FOCL).

For each type of communication lines, a corresponding logical level protocol has been developed that manages the transmission of information over the channel. Logical layer protocols for telephone lines include SLIP (Serial Line Interface Protocol) and PPP (Point to Point Protocol).

For LAN communication, these are packet drivers for LAN boards.

Network layer protocols are responsible for the transfer of data between devices on different networks, that is, they are engaged in routing packets in the network. Network layer protocols include IP (Internet Protocol) and ARP (Address Resolution Protocol).

Transport layer protocols manage the transfer of data from one program to another. Transport layer protocols include TCP (Transmission Control Protocol) and UDP (User Datagram Protocol).

The session layer protocols are responsible for establishing, maintaining and destroying the appropriate channels. On the Internet, the already mentioned TCP and UDP protocols, as well as the UUCP (Unix to Unix Copy Protocol) protocol, do this.

The presentation layer protocols are concerned with the maintenance of application programs. Representative level programs are programs that run, for example, on a Unix server to provide various services to subscribers. These programs include: telnet server, FTP server, Gopher server, NFS server, NNTP (Net News Transfer Protocol), SMTP (Simple Mail Transfer Protocol), POP2 and POP3 (Post Office Protocol), etc.

The application layer protocols are network services and programs for their provision.

The Internet is a constantly developing network, which still has everything ahead, let's hope that our country will not lag behind progress.

/>/>/>/>/>/>/>/>/>/>/>/>Conclusion

A computer network is an association of several computers for the joint solution of information, computing, educational and other tasks.

The main purpose of computer networks is the sharing of resources and the implementation of interactive communication both within one company and

and beyond.

A local computer network is a collection of computers connected by communication lines, providing network users with the potential to share the resources of all computers. On the other hand, to put it simply, a computer network is a collection of computers and various devices that provide information exchange between computers on the network without using any intermediate information carriers.

Global Area Network (WAN or WAN - World Area NetWork) - a network that connects computers that are geographically distant over long distances from each other. It differs from a local area network in longer communications (satellite, cable, etc.). The global network unites local networks.

Internet is a global computer network covering the whole world.

In fact, the Internet consists of many local and global networks belonging to various companies and enterprises, interconnected by various communication lines.

List of used literature

1. “Internet at your home”, S. V. Simonovich, V. I. Murakhovsky, LLC “AST-Press Book”, Moscow 2002.

2. Gerasimenko V.G., Nesterovsky I.P., Pentyukhov V.V. and others. Computing networks and means of their protection: Textbook / Gerasimenko V.G., Nesterovsky I.P., Pentyukhov V.V. and etc. - Voronezh: VSTU, 1998. - 124 p.

3. Weekly for entrepreneurs and specialists in the field of information technology ComputerWeek Moscow.

4. Magazine for users of personal computers World of PC.

5. Kamalyan A.K., Kulev S.A., Nazarenko K.N. et al. Computer networks and means of information protection: Study guide / Kamalyan A.K., Kulev S.A., Nazarenko K.N. and others - Voronezh: VGAU, 2003.-119p.

6. Kurnosov A.P. Workshop on Informatics / Ed. Kurnosova A.P. Voronezh: VGAU, 2001.- 173 p.

7. Malyshev R.A. Local computer networks: Textbook / RGATA. - Rybinsk, 2005. - 83 p.

8. Olifer V.G., Olifer N.A. Network operating systems / V.G. Olifer, N.A. Olifer. - St. Petersburg: Piter, 2002. - 544 p.: ill.

9. Olifer V.G., Olifer N.A. Computer networks. Principles, technologies, protocols / V.G. Olifer, N.A. Olifer. - St. Petersburg: Peter, 2002. - 672 p.: ill.

10. Simonovich S.V. Informatics. Basic course / Simonovich S.V. and others - St. Petersburg: publishing house "Piter", 2000. - 640 p.: ill.