Software(English) software) is a set of programs that ensure the functioning of computers and the solution of problems of subject areas with their help. Software (SW) is an integral part computer system, is a logical continuation of technical means and determines the scope of the computer.
ON modern computers includes a wide variety of programs, which can be divided into three groups (Fig. 3.1):
1. System software ( system programs);
2. Application software (application programs);
3. Tooling (tool systems).
System software (SW) are programs that control the operation of a computer and perform various auxiliary functions, for example, managing computer resources, creating copies of information, checking the performance of computer devices, issuing help information about a computer, etc. They are intended for all categories of users, are used for efficient work computer and user, as well as the efficient execution of application programs.
Central location among system programs occupy operating systems (eng. operating systems). Operating system (OS) is a set of programs designed to manage the loading, launch and execution of other user programs, as well as to plan and manage computer computing resources, i.e. control of the PC operation from the moment it is turned on until the moment the power is turned off. It loads automatically when the computer is turned on, conducts a dialogue with the user, manages the computer, its resources (RAM, disk space, etc.), launches other programs for execution, and provides the user and programs with a convenient way to communicate - interface - with computer devices. In other words, the operating system ensures the functioning and interconnection of all components of the computer, and also provides the user with access to its hardware capabilities.
The OS determines the performance of the system, the degree of data protection, the choice of programs with which you can work on a computer, and hardware requirements. Examples of OS are MS DOS, OS/2, Unix, Windows 9x, Windows XP.
Service systems expand the capabilities of the OS for system maintenance, provide user convenience. This category includes systems Maintenance, OS shells and environments, and utility programs.
Maintenance systems is a set of PC software and hardware tools that perform monitoring, testing and diagnostics and are used to check the functioning of computer devices and detect malfunctions during computer operation. They are a tool for specialists in the operation and repair of computer hardware.
To organize a more convenient and visual user interface with a computer, operating system shells - programs that allow the user to perform actions to manage computer resources other than those provided by the OS (more understandable and efficient). The most popular wrappers include the NortonCommander packages ( Symantec), FAR(FileandArchivemanageR)( E. Roshal).
Utilities (utilities, lat. utilitas benefit) is auxiliary programs, providing the user with a series additional services for the implementation of frequently performed work or increasing the convenience and comfort of work. These include:
Packing programs (archivers), which allow you to more densely record information on disks, as well as combine copies of several files into one, the so-called archive file (archive);
· antivirus programs designed to prevent infection with computer viruses and eliminate the consequences of infection;
programs for optimizing and controlling the quality of disk space;
programs for data recovery, formatting, data protection;
Programs for recording CDs;
Drivers - programs that expand the capabilities operating system on managing input / output devices, RAM, etc. When you connect new devices to your computer, you need to install the appropriate drivers;
communication programs that organize the exchange of information between computers, etc.
Some utilities are part of the operating system, and some are marketed as independent software products, for example, the NortonUtilities feature-packed service utility package ( Symantec).
Application software(PPO) is designed to solve user problems. Its composition includes user applications And application packages (PPP) for various purposes .
user application is any program that contributes to the solution of a problem within a given problem area. Application programs can be used either standalone or as part of software systems or packages.
Application packages (PPP) is in a special way organized software complexes designed for general use in a specific problem area and supplemented by relevant technical documentation. There are the following types of PPP:
· General PPP- universal software products designed to automate a wide class of user tasks. These include:
Text editors(for example, MSWord, WordPerfect, Lexicon);
Table processors(for example, MSExcel, Lotus 1-2-3, QuattroPro);
Dynamic Presentation Systems(for example, MSPowerPoint, FreelanceGraphics, HarvardGraphics);
Database management systems(for example, MSAccess, Oracle, MSSQLServer, Informix);
Graphic editor(for example, CorelDraw, Adobe Photoshop);
Publishing systems(for example, PageMaker, VenturePublisher);
Design automation systems(for example, BPWin, ERWin);
Electronic dictionaries and translation systems(e.g. Prompt, Socrates, Lingvo , Context);
Text recognition systems(eg FineReader, CuneiForm).
General purpose systems are often integrated into multi-component packages for office automation - office packages – Microsoft Office, StarOffice, etc.
· method-oriented RFP, which are based on the implementation of mathematical methods for solving problems. These include, for example, mathematical data processing systems (Mathematica, MathCad, Maple), statistical data processing systems (Statistica, Stat .);
· problem-oriented PPP designed to solve specific task in a specific subject area. For example, information and legal systems YurExpert, YurInform; accounting and control packages 1C: Accounting, Galaxy, Angelica; in the field of marketing – Kasatka, MarketingExpert; banking system STBank;
· integrated PPP are a set of several software products combined into a single tool. The most advanced of these include text editor, a personal manager (organizer), a spreadsheet, a database management system, e-mail support tools, a program for creating presentation graphics. The results obtained by individual subroutines can be combined into a final document containing tabular, graphical and textual material. These include, for example, MSWorks. Integrated packages, as a rule, contain some kind of kernel, which provides the possibility of close interaction between components.
Typically, application software packages have customization tools that allow them to be adapted to the specifics of the subject area during operation.
TO tool software include: programming systems – for the development of new programs, for example, Pascal, BASIC. They usually include: text editor, which provides the creation and editing of programs in the original programming language (source programs), translator, as well as routine libraries; instrumental environments for developing applications, for example, C ++, Delphi, VisualBasic, Java, which include visual programming tools; simulation systems , for example, the MatLab simulation system, BpWin business process modeling systems and ErWin databases, and others.
Translator(English) translator- translator) is a translator program that converts a program from a high-level language into a program consisting of machine instructions. Translators are implemented in the form compilers or interpreters, which differ significantly in terms of how they work.
Compiler(English) compiler- compiler, collector) reads the entire program entirely, translates it and creates a complete version of the program in machine language, which is then executed. After compilation it turns out executable program, which does not require any source program, nor the compiler.
Interpreter(English) interpreter– interpreter, interpreter) translates and executes the program line by line. The program processed by the interpreter must be re-translated into machine language each time it is run.
Compiled programs run faster, but interpreted programs are easier to fix and change.
4 Hardware and software
^ IT and IS organization management
The use of technical means based on the systemic and complex integration of all equipment, taking into account a number of requirements.
The main components of technical support are computers of different classes, scales of action, universal and specialized, as well as the means of their interaction and communication, i.e. network equipment.
System and application programs in the software, their impact on the performance of the user - an economist.
A variety of software market offerings, user evaluation of their suitability and quality in relation to monetary costs, as well as their applicability in specific enterprises.
^
4.1. The composition of the technical support of IT and IS organization management
The technical basis of IT and IS management is represented by a set of interrelated unified management autonomous technical means of collecting, accumulating, processing, transmitting, outputting and presenting information, means of processing documents and office equipment, as well as means of communication for information exchange between various technical means.
Achieving the effective operation of the IS involves the fulfillment of a certain set of requirements for the complex of technical means (CTS), the main of which are the following:
· minimization of labor and cost costs for solving the whole complex of system tasks;
Implementation of integrated information processing due to information, technical and software compatibility of various technical devices;
providing users with communication through terminal devices with a distributed database; high reliability;
Availability of protection of information from unauthorized access;
· feasibility of CTS, I.e. the possibility of its creation at the expense of standard means produced by the domestic industry;
flexibility of the CTS structure, I.e. the prospect of including new, more advanced technical means in its composition as they are mastered by industry;
· minimization of capital costs for the purchase of CTS and their current operation.
The effective functioning of IS is based on the integrated use of modern technical means of information processing and methods for organizing technological processes for solving problems. basis further development automation management activities in various sectors of the economy is a new, progressive information technology, focused on the use of the latest achievements of electronic technology, in particular, high-performance, high-speed computers and modern means of communication.
The creation of a new technology requires taking into account the peculiarities of the structure of economic systems. First of all, this is the complexity of organizational interaction, which necessitates the creation of multi-level hierarchical systems (parent company, branches) with COMPLEX information links of forward and reverse directions with related organizations.
The main element of the complex of technical means intended for automatic processing information in the process of solving managerial problems is an electronic computer, or computer.
In the field of economics, these are computers. different power, performance, size. They are designed to solve a variety of problems: economic, mathematical, informational and other problems, characterized by the complexity of algorithms and a large amount of processed data, and are widely used in powerful computing systems.
Characteristic features of modern computers are: high performance; a variety of forms of processed data - binary, decimal, symbolic, with a large range of their changes and high representation accuracy; an extensive range of operations performed, both arithmetic, logical, and special; large capacity random access memory; advanced organization of the information input-output system, providing connection of various types of external devices.
Problem-oriented computing facilities are used to solve a narrower range of problems associated, as a rule, with the management of technological objects, the registration, accumulation and processing of relatively small amounts of data, and the performance of calculations using relatively simple algorithms. They are limited compared to mainframe computers hardware and program resources. The problem-oriented ones include, in particular, all kinds of control computing systems.
^ Specialized computing tools are used to solve a narrow range of problems or to implement a strictly defined group of functions. Such a narrow orientation makes it possible to clearly specialize the structure, significantly reduce the complexity and cost of computers while maintaining high performance and reliability of their operation. Specialized ones include, for example, programmable microprocessors for special purposes.; adapters and controllers that perform logical control functions for individual simple technical devices, units and processes; devices for coordinating and interfacing the operation of computer system nodes.
In terms of size and functionality, computers used in management activities are divided into super-large (mainframe), large, small, ultra-small (microcomputers).
The functionality of modern computers is distinguished by:
speed, measured by the average number of operations performed by the machine per unit of time;
bit depth and forms of representation of numbers with which the computer system operates;
nomenclature, capacity and speed of all storage devices;
· nomenclature and technical and economic characteristics of external devices for storage, exchange and input-output of information;
Types and bandwidth of communication devices and interfacing of computer nodes with each other (in-machine interface);
the ability of a computer to simultaneously work with several users and execute several programs at the same time (multiprogramming);
types and technical and operational characteristics of the operating systems used in the machine;
Availability and functionality of the software;
the ability to execute programs written for other types of machines (software compatibility with other computers);
The system and structure of machine instructions:
the ability to connect to communication channels and to a computer network;
operational reliability of computers;
· the coefficient of useful use of computers in time, determined by the ratio of useful work time and preventive maintenance time.
^ 5 Management information technology
According to experts, about 70% of computer information is now on mainframes; in the US alone, 400,000 mainframes were installed in 1998. About 5 thousand ES computers and about the same number of branded mainframes are currently used in Russia: IBM (ES / 9000 installed at car factories, metallurgical plants), Нitachi Data System, Fujitsu, etc.
Small computers are reliable, inexpensive and easy to use, with slightly lower capabilities than mainframes.
Mini computers (and the most powerful superminis) have the following characteristics:
productivity - up to 100 MIPS;
main memory capacity - 4-512 MB:
· capacity of disk memory - 2-100 GB;
· number of supported users - 16-512.
All used models of this type are developed on the basis of microprocessor sets of integrated circuits, 16-, 32-, 64-bit microprocessors. Wide range of performance in specific application conditions, hardware implementation of most system I/O functions, simple implementation of microprocessor and multi-machine systems, high speed interrupt processing, the ability to work with data formats of various lengths make them convenient to use in IT management.
The advantages of computers include: a specific architecture with great modularity, a better performance / price ratio than mainframes, and increased accuracy of calculations. They are intended for use as part of control computing systems. The wide range of peripheral devices traditional for such complexes is complemented by interprocessor communication units, which ensures the implementation of computing systems with a variable structure.
Computers are successfully used for calculations in multiuser computing systems, in systems computer-aided design, in systems for modeling simple objects, in artificial intelligence systems.
The personal computer satisfies the requirements of general availability and universality of application and has the following characteristics:
low cost, which is within the reach of an individual buyer;
Autonomy of operation without special requirements for environmental conditions;
the flexibility of architecture, ensuring its adaptability to a variety of applications in the field of management, science, education, and everyday life;
. “friendliness” of the operating system and other software, which makes it possible for the user to work with it without special professional training;
High reliability of work (more than 5000 hours of time between failures).
In the field of management activities, personal computers manufactured by American companies Compaq Computer, Apple (Macintosh), Hewlett Packard, Oell, OEC, as well as British firms - Spectrum, Amstrad; France - Micral;
Italy - 0livetty; Japan - Toshiba, Panasonic and Partner.
The most popular at present are clone personal computers (architectures of a certain direction) (VMs, the first models of which appeared in 1981. Personal computers of the OEC (Digital Equipment Corporation) clone, in particular, the well-known Apple Macintosh PCs, occupying 2nd place in distribution.
At the beginning of 2000, the global fleet of computers was approximately 250 million units, of which about 90% were personal computers, in particular, there were more than 100 million units of professional PCs of the IBM PC type. (about 75% of all PCs); professional PCs of the OEC type - about 5 million pcs.
Abroad, the most common computer models at present are computers with Pentium and Pentium Pro microprocessors (Table 4.1).
Table 4.1. Average characteristics of modern IR /VM Re
| Parameter | Microprocessor type |
|||||
| 80386SX | 80386 OH | 80486SX | 80486 OH | Pentium | Pentium Pro |
|
| Clock frequency, | 25-40 | 33-40 | 33-80 | 50-100 | 60-150 | 100-400 |
| Bit depth, bit | 32 | 32 | 32 | 32 | 64 | 64 |
| RAM size, MB | 1;2;4 | 2;4;8 | 2;4;8 | 4;6;8 | 8;16 | 16;32 |
| Volume of cache memory, KB | Not | 64,128 | 128;256 | 256;512 | 512;1024 | 512;1024 |
| HDD capacity, MB | 210 | 420 | 540 | 850 | 2000 | 10000 |
| Video adapter VGA/SVGA,% | 30/70 | 24/76 | 10/90 | 0/100 | 0/100 | 0/100 |
| Presence of a coprocessor | 45 | 67 | 80 | 100 | 100 | 100 |
^ A special intensively developing group of computers is formed by multi-user servers used in computer networks. Servers are usually classified as microcomputers, but in terms of their characteristics, powerful servers are more likely to be attributed to small computers and even to mainframes, and superservers are closer to supercomputers.
Server - a computer dedicated to processing requests from all stations of a computer network that provides these stations with access to common system resources (computing power, databases, software libraries, printers, faxes, etc.) and distributes these resources. Such a generic server is often referred to as an application server.
^ Servers on a network are often specialized. Specialized servers are used to eliminate the most bottlenecks in network operation: creation and management of databases and data archives, support for multicast facsimile and e-mail, management of multi-user terminals (printers, plotters), etc.
File Server(File Server) is used to work with data files, has large disk storage devices, often on fault-tolerant disk arrays KAyu with a capacity of up to 1 TB.
^ Archive server (server Reserve copy) serves to back up information in large multi-server networks, uses magnetic tape drives (streamers) with replaceable cartridges with a capacity of up to 5 GB; usually performs daily automatic archiving with compression of information from servers and workstations according to a scenario set by the network administrator (naturally, with the compilation of an archive catalog).
fax server(Net Satisfaxiop) - a dedicated workstation for organizing efficient multicast facsimile communication with several fax modem cards, with special protection of information from unauthorized access during transmission, with an electronic fax storage system.
^ Mail server(Mail Server) - the same as the fax server, but for organizing e-mail, with electronic mailboxes.
Print server(Print Server, Net Port) is intended for effective use system printers.
^ Teleconferencing Server has a system for automatic processing of video images, etc.
A rapidly developing subclass of personal computers are portable computers (notebook, laptop).
Majority laptop computers It is self-powered by batteries, but can also be connected to the network.
As video monitors, they use flat liquid crystal displays with a video projector, less often - luminescent for presentations or gas discharge.
Portable computers are very diverse: from bulky and heavy (up to] 5 kg) portable workstations to miniature electronic notebooks weighing about 100 g. Portable workstations are the most powerful and large portable PCs.
They are often made in the form of a suitcase and carry the slang name Nomadic - a nomad. Their characteristics are similar to those of stationary PCs - workstations: powerful microprocessors, often of the RISC type, with clock frequency up to 300 MHz; RAM up to 64 MB; gigabyte disk drives; high-speed interfaces and powerful video adapters with video memory up to 4 MB.
In essence, these are ordinary workstations powered by the mains, but structurally designed in a case that is convenient for portability, and having, like all portable PCs, a flat liquid crystal video monitor of a class not higher than UAA. Nomadic usually have modems and can quickly connect to communication channels to work in a computer network.
The main development trend computer science At present, there is a further expansion of the scope of computers and, as a result, the transition from individual machines to their systems - computing systems and complexes of various configurations with a wide range functionality and characteristics.
The most promising, created on the basis of personal computers, geographically distributed multimachine computing systems - computer networks - are oriented not so much towards computational processing of information, but rather towards communication information services: email, teleconferencing systems and information and reference systems.
The Intemet network implements the principle of hypertext, according to which the subscriber, by choosing keywords found in the readable text, can receive the necessary additional explanations and materials.
In the development and creation of modern PCs, a significant and stable priority in recent years has been heavy duty computers- supercomputers, as well as miniature and subminiature PCs. Research work is underway to create computers of the 6th generation based on the distributed neural architecture of neurocomputers.
The widespread introduction of multimedia, primarily audio and video input and output of information, will allow you to communicate with a computer in natural language.
Federal State Educational Institution
higher and professional education
"SOUTH FEDERAL UNIVERSITY"
INSTITUTE OF ECONOMY AND FOREIGN ECONOMIC RELATIONS
College of Economics
COURSE WORK
On the topic:"Technical support of AIS"
Subject: AIS
Day student
Groups No. 2007-3-ACS
Speciality
Asmerzaeva Karina Igorevna
Scientific adviser:
Bordyugova T.
Rostov-on-Don
Introduction
1.2 Structure and organization of AIS maintenance
1.3 Calculation of the optimal AIS maintenance
Chapter 2
Conclusion
Introduction
The evolution of technical support, which includes hardware, communications, software, is uneven, abrupt. The development of computer technology is still taking place exponentially. Computer performance doubles every four years.
Classification computer technology by type of user interface (how the user of the technology interacts with the computer) - rocket, interactive, network. In the first case, the user receives only the results of the technology, in the other cases, he interacts with it on an individual computer or a computer connected to a computer network.
Modern technical means of ensuring the management of information resources are very diverse in their composition and functionality. Computer equipment, communication equipment, organizational equipment.
Computer equipment is intended mainly for the implementation of complex technologies for processing and storing information and is the basis for the integration of all modern technical means of ensuring the management of information resources.
Communication equipment is intended mainly for the implementation of information transfer technologies and involves both autonomous operation and operation in combination with computer equipment.
Organizational technology is designed to implement technologies for storing, presenting and using information, as well as to perform various auxiliary operations within the framework of certain technologies. information support management activities.
To date, two main forms of organizing technical support (forms of using technical means) have developed: centralized and partially or completely decentralized.
Centralized technical support is based on the use of large computers and computer centers in the information system.
Decentralization of technical means involves the implementation functional subsystems on personal computers directly at the workplace.
A promising approach should be considered a partially decentralized approach - the organization of technical support based on distributed networks, consisting of personal computers and mainframe computers for storing databases common to any functional subsystems.
The purpose of the course work is to study the organization of the technical support of automated information systems (AIS) using the example of the Tekhnosila store.
Objectives of the course work: consideration of the main requirements and characteristics of modern and the use of technical means of AIS, to study the structure and organization of AIS maintenance, to analyze the features of the organization of optimal maintenance of AIS, and also to develop information support for accounting for the vehicle of the Technosila store.
Chapter 1. Theoretical features of the organization of technical support
1.1 Basic requirements and characteristics of modern and application of technical means of AIS
Automated information system (AIS) is a set of information, software, technical, organizational, methodological and other necessary tools that ensure the collection, processing, storage, transmission of data, as well as their manipulation to solve various problems.
As a rule, the composition of the AIS includes:
Information resources presented in the form of databases (knowledge bases) that store data about objects, the relationship between which is specified by certain rules;
Formal logical-mathematical system implemented in the form of software modules that provide input, processing, search and output of the necessary information;
An interface that provides communication between the user and the system in a form convenient for him and allows him to work with database information;
Personnel who determine the procedure for the functioning of the system, planning the procedure for setting tasks and achieving goals;
Complex of technical means.
Information resources include machine and non-machine information. Machine information is presented in the form of databases, knowledge bases, data banks. Databases (banks) of data can be centralized or distributed.
The complex of technical means (CTS) includes a set of computer equipment (computers of different levels, operator workplaces, communication channels, spare elements and devices) and a special complex (means for obtaining information about the state of the control object, local control tools, actuators, sensors and devices control and adjustment of technical means).
Software (software) consists of general software (operating systems, local and global networks and complexes of maintenance programs, special computing programs) and special software (organizing programs and programs that implement control and management algorithms).
Personnel and instructive and methodological materials constitute the organizational support of the system.
Procedures and technologies are developed on the basis of logical-mathematical models and algorithms, which form the basis of the mathematical support of the system, and are implemented using software and CTS, as well as an interface that provides user access to information.
For example, in the composition expert system(ES) includes:
An interface that allows you to transfer information to the database and contact the system with a question or for an explanation;
Working memory (DB), which stores data about objects;
Dispatcher, which determines the order of functioning of the ES;
An inference engine is a formal-logical system implemented as a software module.
Knowledge base (KB) is a collection of all available information about the subject area, recorded using formal knowledge representation structures (a set of rules, frames, semantic networks).
The most important component of the ES is the block of explanations. It allows the user to ask questions and get reasonable answers.
Technical support is understood as the composition, forms and methods of operation of various technical devices necessary to perform information procedures: collection, registration, transfer, storage, processing and use of information.
The elements of technical support include: a set of technical means, organizational forms of using technical means, personnel who work on technical means, instructional materials on the use of technology.
The complex of technical means is a set of interconnected technical means intended for automated data processing.
Requirements for the complex of technical means:
Minimization of acquisition and operation costs;
Reliability;
Protection against unauthorized access;
Rational distribution by processing levels.
The complex of technical means includes:
A. Means of collecting and recording information:
Automatic sensors and counters for fixing the occurrence of any events, for calculating the values of individual indicators;
Scales, watches and other measuring devices;
Personal computers for entering document information and recording it on media;
Scanners for automatic reading of data from documents and their transformation into graphical, digital and text representation.
B. Complex of means of information transmission:
GPS communication;
Computer networks (local, regional, global);
means of telegraph communication;
Radio communication;
Satellite communications, etc.
B. Storage media:
Optical discs (CD, DVD);
USB drives (flash, HDD);
Hard disk (2.5",3.5").
D. Data processing facilities or computers, which are divided into classes:
supercomputers;
A laptop:
Pocket computer.
They differ in technical and operational parameters (memory capacity, speed, etc.).
D. Information output means:
Monitors;
Printers;
Plotters.
E. Means of organizational technology:
Production, copying, processing and destruction of documents;
Special facilities (ATMs), detectors for counting banknotes and checking their authenticity, etc.
1.2 Structure and organization of AIS technical support
Hardware is a set of technical means designed for the operation of an information system, as well as the relevant documentation for these tools and technological processes.
The complex of technical means consists of:
Computers of any models;
Devices for collecting, accumulating, processing, transmitting and outputting information;
Devices for data transmission and communication lines;
Office equipment and devices for automatic data retrieval;
Operational materials, etc.
To date, two main forms of organizing technical support (forms of using technical means) have developed - centralized and partially or completely decentralized.
Centralized technical support is based on the use in the information system large computers and computer centers.
Decentralization of technical means involves the implementation of functional subsystems on personal computers directly at workplaces. A promising approach should be considered, apparently, a partially decentralized approach - the organization of technical support based on distributed networks, consisting of personal and large computers for storing databases common to any functional subsystems.
Mathematical and software - a set of mathematical methods, models, algorithms and programs for the implementation of the goals and objectives of the information system, as well as the normal functioning of the complex of technical means.
The software tools include:
Tools for modeling management processes;
Typical control algorithms;
Methods mathematical programming, mathematical statistics, queuing theory, etc.
The software includes general system and special software products, as well as technical documentation, Fig.1.1.
Figure 1.1 - Information system software
System-wide software includes software complexes that are user-oriented and designed to solve typical problems of information processing. They serve to expand the functionality of computers, control and manage the data processing process.
Special software is a set of programs developed during the creation of a specific information system. It includes application software packages that implement the developed models of varying degrees of adequacy, reflecting the functioning of a real object.
Technical documentation for development software tools should contain a description of the tasks, a task for algorithmization, an economic and mathematical model of the task, test cases.
Organizational support - a set of methods and means that regulate the interaction of employees with technical means and among themselves in the process of developing and operating an information system. Organizational support is created based on the results of a pre-project survey of the organization. Organizational support implements the following functions:
Analysis of the existing management system of the organization, where the information system will be used, and identification of tasks to be automated;
Preparation of tasks for solving on a computer, including terms of reference for the design of an information system and a feasibility study of efficiency;
Development of management decisions on the composition and structure of the organization, methodology for solving problems aimed at improving the efficiency of the management system.
Legal support- a set of legal norms that determine the creation, legal status and functioning of information systems that regulate the procedure for obtaining, transforming and using information.
The main purpose of legal support is to strengthen the rule of law. The composition of legal support includes laws, decrees, resolutions of state authorities, orders, instructions and other regulatory documents of ministries, departments, organizations, local authorities.
In legal support, one can distinguish general part, which regulates the functioning of any information system, and the local part, which regulates the functioning of a particular system. Legal support for the stages of development of an information system includes standard acts related to contractual relations between the developer and the customer and the legal regulation of deviations from the contract.
Legal support for the functioning of the information system includes:
Information system status;
Rights, duties and responsibilities of personnel;
Legal provisions of certain types of management process;
The procedure for creating and using information, etc.
Requirements for the complex of technical means: minimization of acquisition and operation costs; reliability; protection against unauthorized access; rational distribution by processing levels.
Ways of using technical means are usually called organizational forms of using machines. In practice, they are used in 2 types: 1) computer centers ; 2) local workstations (AWP) and computer networks .
Computing centers are used in large enterprises, banks, government bodies. These are specific information processing enterprises. They are equipped with large computers, and personal computers and terminals are used as auxiliary ones. On the computer centers there is a management system (management), departments for setting tasks, programming, machine maintenance, as well as production divisions - groups for accepting documents, transferring information to media, administration of data banks, information release, reproduction of materials, etc.
For automated workstations (AWPs) of specialists, it is typical to place computers at workplaces, in separate accounting areas, which can be connected to a network, connected to large computers.
1.3 Calculation of the optimal technical support of AIS
As you know, the implementation of each main technological process requires the presence of auxiliary (secondary) processes that ensure effective activities for the provision of information services. All planned activities, processes, complexes of hardware and software must be supported by the relevant services that need to be prepared, organized, trained, which requires appropriate financial costs, determined by environmental factors.
Thus, the optimization model at each level generates the appropriate output parameters while minimizing economic (financial) indicators, taking into account external factors.
The main sources of funding for the information center are: budget; self-supporting activity; sponsorship (individual, corporate, associative); grants; target (departmental) financing.
It should be noted that the ratio between the volumes of these types of financing depends on the economic and social policy of the state. In modern conditions, budgetary and targeted funding allocated to replenish fixed assets is constantly decreasing. Therefore, for the necessary replenishment of information resources, the missing part of the funds is allocated from self-supporting income. Funding for the acquisition of funds under the grant is not provided for by the rules for granting it.
The listed funding sources are not equally used to support certain library and information processes. So, for example, to replenish information resources, budget allocations, self-supporting funds, sponsorship, targeted funding are used. The sources of financial support for scientific, practical, analytical, and methodological developments are self-supporting income, funds allocated by grants, and sponsorship.
Thus, the application of the optimization model of program-target planning in the control system information exchange allows for the rational distribution of the generalized financial potential for the main activities of the information center, taking into account all the necessary resources in achieving the main strategic goal. The choice of the main target functions (criteria) and the system of restrictions allow us to formulate, according to the goals, a certain set of strategies that determine the behavior of the center's management when making a decision. As a result, the necessary list of measures is formed to ensure effective system information exchange management. Such a statement of the optimization problem makes it possible to determine the real need for resources necessary to achieve the set goals, taking into account the complex feasibility or effectiveness of their implementation, depending on the timing and scale of the introduction of new technologies and the results of scientific developments.
Thus, the information exchange management system is an integrated hierarchical system that includes subsystems with common information bases of economic, technical, qualitative indicators of the center's activities and their coordination links. It is very important to comply with the following requirements:
1. The management system should provide each manager with the information necessary to analyze and choose between alternative courses of action, to plan outcomes, as well as actions aimed at achieving these outcomes and implementing corrective actions.
2. The system must ensure the collection and processing of actual data.
3. The system should correspond to the organizational structure of the information center so that the controlled parameters of the work of each structural unit can be measured in terms of its contribution to the overall activities of the library and information center.
4. The system should be integrated to such an extent that information is aggregated across levels of the hierarchy, i.e. information at a lower level should be more specific than at a higher one.
5. In the system, the information used for planning should be different from that used for control, although the formation of each of these types requires accounting for a different type.
6. Information data supplied by the system must be timely; they should cover the past, present and future and reflect all the main indicators of the center's activities.
7. The system should be flexible enough to ensure the possibility of operational management of new structures (processes) and their control.
8. When developing control actions, it is necessary to take into account both the information received during the implementation of the main processes and the opinions of the managers who provide it.
9. The system should, to the fullest extent possible, take into account and select information about such factors of production and the environment, on which the success and efficiency of the functioning of library and information systems most of all depend.
10. To achieve an acceptable balance, it is necessary that subsequent control information corresponded to the management style of the heads of the respective departments.
11. Special reporting materials should cover the most important periods of time and reflect the achievements of the center, help verify the implementation of plans, and include only real facts. They should also be readable and understandable, have a clear purpose, be based on specific plans, and be built in accordance with the workflow technology.
12. Active use required automated systems for the process of management and decision making.
13. It should be possible to improve and modernize the management system, but constant reworking for every minor issue is unacceptable.
This system has been implemented in the RBITS of the Ministry of Health of the Republic of Tajikistan and ensures its effective operation for many years in the information services market.
2.1 General characteristics of the technological support of the Technosila store
Trading network of stores household appliances Technosila was established in 1993. To date, Technosila is one of the leaders in the Russian home appliances and electronics market and has 242 stores in 191 Russian cities. Since 2005, the online store "Technosila" has been operating.
The stores of the network have spacious halls, modern convenient trade equipment, convenient display of goods. The store takes responsibility for the delivery of bulky goods to the buyer's home.
Promotions and special offers are held on a regular basis. In all cities where Technosila stores operate, there are service centers of the trading network, certified by leading manufacturers of electronics and household appliances.
The company provides customers with a variety of different types of equipment. In this regard, I would like to use not the entire range of goods offered on the market as data. Let's focus on air conditioners, air cleaners and fans.
Before starting work on creating a database, it is necessary to form a concept about the objects, facts and events that this system will operate with. In order to bring these concepts to a particular data model, it is necessary to replace them information representations. One of the most handy tools The unified data representation is the entity-relationship model, or ER-model.
This model is based on some important semantic information about the real world and is designed to represent data logically. It defines the meaning of data in the context of its relationship with other data. It is important that all existing data models can be generated from the entity-relationship model. Therefore, it is the most general.
Domain modeling is based on the use of graphical diagrams that include a small number of heterogeneous components. The basic concepts of this model are entity, relationship, attribute.
An entity is a real or imagined object about which information is stored and must be available.
A relationship is a graphical association established between two entities. It is binary and can exist between two different entities or between an entity and itself.
2.2 Building an ER-model for AIS information support
Consider the ER model of our database. As I have already noted, in order to avoid bulkiness, we will consider certain types of products offered by the store. Three tables will be involved in the database: quantity in stock, price and selling price. Let's define relationships between two tables and present an ER model.
Figure 2.1 - ER-model of the infobase
When developing ER models, we must obtain the following information about the subject area:
1. List of entities of the subject area.
2. List of entity attributes.
3. Description of relationships between entities.
ER diagrams are convenient in that the process of extracting entities, attributes, and relationships is iterative. Having developed the first approximate version of the diagrams, we refine them by interviewing subject matter experts. At the same time, the documentation in which the results of the conversations are recorded are the ER diagrams themselves.
Suppose we are faced with the task of developing an information system for a certain wholesale trading company. First of all, we must study the subject area and the processes taking place in it. To do this, we interview company employees, read documentation, study order forms, invoices, etc.
For example, during a conversation with a sales manager, it turned out that he (the manager) believes that the system being designed should perform the following actions:
Store customer information.
Print invoices for released goods.
Monitor the availability of goods in stock.
Let's select all the nouns in these sentences - these will be potential candidates for entities and attributes, and analyze them (we will highlight incomprehensible terms with a question mark):
The buyer is a clear candidate for an entity.
An invoice is a clear candidate for an entity.
The product is a clear candidate for an entity.
Warehouse - in general, how many warehouses does the company have? If multiple, then it will be a candidate for a new entity.
The presence of a product is most likely an attribute, but an attribute of which entity?
Immediately there is an obvious connection between the entities - "customers can buy many products" and "products can be sold to many buyers." The first diagram looks like this:
Figure 2.2 - ER-model "Buyer - Product"
Having asked additional questions to the manager, we found out that the company has several warehouses. Moreover, each product can be stored in several warehouses and be sold from any warehouse.
Where to place the entities "Invoice" and "Warehouse" and what to associate them with? Let's ask ourselves how these entities are related to each other and to the entities "Buyer" and "Product"? Buyers buy goods, while receiving invoices, which contain data on the quantity and price of the purchased goods. Each buyer can receive multiple invoices. Each invoice must be issued for one buyer. Each waybill must contain several goods (there are no empty waybills). Each item, in turn, can be sold to multiple customers via multiple invoices. In addition, each invoice must be issued from a specific warehouse, and many invoices can be issued from any warehouse. Thus, after clarification, the diagram will look like this:
Figure 2.3 - ER-model "Buyer - Invoice - Warehouse - Goods"
It's time to think about entity attributes. In our interviews with the company's employees, we found the following:
Each buyer is a legal entity and has a name, address, bank details.
Each product has a name, price, and is also characterized by units of measurement.
Each invoice has a unique number, an issue date, a list of items with quantities and prices, and the total amount of the invoice. The invoice is issued from a specific warehouse and for a specific customer.
Each warehouse has its own name.
Again, we write out all the nouns that will be potential attributes, and analyze them:
Legal entity is a rhetorical term, we do not work with individuals. We don't pay attention.
The name of the buyer is a clear characteristic of the buyer.
The address is a clear characteristic of the buyer.
Bank details - a clear characteristic of the buyer.
The name of the goods is a clear characteristic of the goods.
The price of the product - it seems that this is a characteristic of the product. Is this characteristic different from the price in the invoice?
A unit of measurement is an explicit characteristic of a product.
The invoice number is an explicit unique characteristic of the invoice.
The date of the invoice is an explicit characteristic of the invoice.
List of goods on the invoice - the list cannot be an attribute. Probably, you need to separate this list into a separate entity.
The quantity of goods on the invoice is an obvious characteristic, but what characteristic? This is not just a characteristic of "goods", but "goods on the waybill".
The price of the goods on the invoice - again, this should be not just a characteristic of the goods, but a characteristic of the goods on the invoice. But the price of the goods has already met above - is it the same thing?
The amount of the invoice is an explicit characteristic of the invoice. This characteristic is not independent. The amount of the invoice is equal to the sum of the costs of all goods included in the invoice.
The name of the warehouse is a clear description of the warehouse.
In the course of an additional conversation with the manager, various concepts of prices were clarified. It turned out that each item has some current price. This is the price at which the product is currently being sold. Naturally, this price may change over time. The price of the same product in different invoices issued in different time, may be different. Thus, there are two prices - the price of the item on the invoice and the current price of the item.
With the emerging concept of "List of goods on the invoice" everything is pretty clear. The "Invoice" and "Product" entities are related to each other by a many-to-many relationship. Such a relationship, as we noted earlier, should be split into two one-to-many relationships. This requires an additional entity. This entity will be the "List of goods on the invoice" entity. Its connection with the entities "Invoice" and "Goods" is characterized by the following phrases - "each invoice must have several entries from the list of goods on the invoice", "each entry from the list of goods on the invoice must be included in exactly one invoice", "each product can be included to several entries from the list of goods on the invoice", "each entry from the list of goods on the invoice must be associated with exactly one product". The attributes "Quantity of goods on the invoice" and "Price of goods on the invoice" are attributes of the "List of goods on the invoice" entity.
Let's do the same with the connection connecting the entities "Warehouse" and "Goods". Let's introduce an additional entity "Goods in stock". The attribute of this entity will be "Quantity of goods in stock". Thus, the goods will be listed in any warehouse and its quantity in each warehouse will be different.
2.3 Creation of a database of registration and sale of vehicles
When working with a database, the user, as a rule, does not need to see all the information stored in one or another database table at the same time. On the contrary, there is often a need to display the contents of several tables at once, corresponding to certain conditions.
Access has a powerful tool for processing data in related tables, which allows you to display the necessary information that meets the specified requirements - a query.
There are two main types of queries: a select query and a data change query.
The select request is the most common. When it is executed, a set of records is formed, the information for which is taken from one or more tables. We will use it in our database.
Let's create four requests: a request for the quantity of goods, for the price, cost and for the goods.
Note that using queries, we can display only the information we need at the moment. We do not have to scroll through entire tables in order to find the required data, which significantly saves both time and effort. In our example, the tables are relatively small. But in most cases it is necessary to operate with big amount tables and data. Therefore, the role of queries in working with the database is difficult to overestimate.
Working with data in the database is carried out directly in tables and queries. At the same time, the proposed possibilities for changing the structures of tables and the data contained in them are more useful to the developer than to the user. In addition, for ease of use, Access has ample opportunities to create a user interface using forms. When creating a form, the developer has several goals:
Display and change data. Most often, forms are used just for this. In this case, the developer can set any type of information display;
Data input. Forms can be used to enter new data into a table. In this case, the input will be performed by the user in the format specified by the developer. In other words, the user can only enter values for the fields that are present on the form;
Seal. Despite the fact that reports are used to print data in the database, the contents of the form can also be printed;
Messages. Additional feature The use of forms is to create with their help various messages that are subsequently displayed in a given situation to facilitate the user's work. In this form, forms are used in applications.
Depending on the purpose for which the form is created, the developer determines the features of its appearance. We highlight the following:
Multi-page - record fields are displayed in one column. At the same time, only the contents of the current record are displayed in the form at the same time (for example, the “quantity of goods” form);
Tape - all fields of the record are displayed in one line, while all records are displayed in the form (for example, the form "realization price");
Tabular - records are displayed in the form of a table.
Reports are designed to print information from the database in Access. Compared to other printing methods, when using reports, in addition to displaying the contents of fields from tables and queries, you can calculate various totals, as well as group data. The Technosila database contains reports on the quantity in stock, cost and sales price.
MicrosoftAccess contains various types of macros that allow you to automate the operation of an application. A macro is a set of one or more commands that perform specific operations. Here are examples of situations where it is convenient to use macros in applications: - to perform simple tasks, such as opening and closing forms, displaying and hiding toolbars, or running reports;
In cases where it is not required to track and handle errors;
To define common assigned keys;
To create a special menu bar, as well as sub menus for forms;
To execute a macro or set of macros when a database is opened.
Macros allow:
Open a table, query, form, or report in any available mode. They also allow you to close open table, request, form, report;
Open the report in preview mode or directly output either the entire report to the printer, or only a selected part of it;
Execute a select request or a change request;
Perform actions based on values in a database, form, or report;
To carry out both the transition to any record, and to search for data that meets the search conditions in the form data source;
Execute Access menu commands, etc.
Our database contains a macro that calls a cost report and a sales price report.
Now let's make a cascade model of the life cycle of AIS "Technosila".
Life cycle model - a structure that defines the sequence of execution and the relationship of processes, activities and tasks performed throughout the life cycle.
There are two main life cycle models that are most widely used:
1) cascade model 2) spiral
The cascade method is the division of the entire development into stages, and the transition from one stage to the next occurs after the work on the current one is fully completed.
1. Analysis:
When analyzing the AIS "Technosila", a number of requirements were identified:
AIS "Technosila" must have data on the product, its price and availability;
The client must be provided with an information base about the goods of the store;
2. Design:
All data about the product, its availability and price are entered into a common database for further use. IN common base includes three tables with a description of the product and all the data about it.
3. Implementation:
The created Database for AIS "Technosila" should be fully or partially available to employees. To do this, you need to launch the Database in the corporate network.
4. Introduction:
After the introduction of the Database into the corporate network, it is necessary to monitor its performance.
5. Escort:
At the end of the service life, it is necessary to identify all changes in the Software in order to correct errors and introduce new functionality.
So, we have created a database of a hardware store, while creating tables containing information about the product, queries, reports and macros. This database will help organize data into a single whole, provide flexible access and more convenient work. The reports, queries, and macros created in the process are not universal. The user, independently or with the help of a wizard, can supplement the database with new queries, reports and macros that are necessary for him. It will not be difficult, if desired, to expand the base. To do this, you need to create new tables, enter the necessary data into them, and then make new connections between existing tables and those created.
Conclusion
Our life is so full of various information that it is almost impossible to store it without the help of computer technology. Working with large volumes of information without the help of a computer is already unacceptable both in terms of the cost of storing it, and in terms of information management and speed of access to it.
Thus, such an urgent need for ordering data, creating a database is quite obvious. Dynamics, a tendency to variability of information forces us to look for new methods and means to manage this dynamics, and not purely adapt to it. Thus, the system we have considered, which just allows you to manage data, will undoubtedly find application not only in the trading business, but also in other sectors of the national economy.
List of used literature
1. "1C: Accounting", Handbook of the user. – M.: 1999.
2. Bank V.R., Zverev B.C. Automated information technologies in the economy: Proc. / ASTU. - Astrakhan: Publishing House of ASTU, 2000.
3. Braga V.V. Computerization of accounting. – M.: Finstatinform, 1996.
4. Vasina E.N., Partyka T.L., Popov I.I. Automated information systems of accounting. – M.: Infra-M, 2010.
5. Elochkin M.E. Information Technology. - M .: Mir and education, 2009.
6. Sapkov V.V. Information technologies and computerization of office work. – M.: Academia, 2010.
7. Chistov D.V. Information systems in the economy. – M.: Infra-M, 2010.
Since the beginning of the 80s of the 20th century, in connection with mass production and the introduction of personal computers (PCs), the idea of system automation of the design process has become practically feasible for design organizations of any scale: from a large institute to a private bureau. The concept of CAD, on the one hand, has become simpler and is often associated with a particular computer program. On the other hand, the design of complex technical objects is possible only within the framework of CAD as an organizational and technical systems, based which - the full potential of information technology.
CAD software is classified as a unity of the following components: technical, software, mathematical, methodological, informational and organizational.
2.1. Hardware and software
Technical support- this is a set of technical means with the help of which they collect, process, store, transform and transfer data related to the design object.
The basis of technical support is computer technology and, first of all, it is a personal computer.
The standard computer configuration is well known (see Figure 2.1):
· a system unit consisting of a processor, RAM, power supply, hard drive, other data storage devices, ports for connecting peripheral devices;
· keyboard for entering information;
· monitor for displaying information;
· mouse for the convenience of human-computer dialogue.
Rice. 2.1. Standard configuration personal computer
The concept of peripheral devices includes a wide range of technical means. First of all, these are means of collecting and processing data for design. These include electronic geodetic equipment (total stations, satellite navigation systems, laser scanners, etc.), which either operates directly under the control of computers, or transmits measurement data in the form of computer files. More detailed information about the technical means of engineering surveys is given in Ch. 4.
If the initial information about the projected road is presented in the form of tablets of topographic plans, then to convert information from paper to electronic form, scanners(see Fig. 2.2, a) . Scanners can be roll or flatbed. The scanning accuracy of the latter is much higher and can reach 12000 dpi (dots per inch - dots per inch). When we are talking about the design of complex technical objects, then engineering scanners are used large format A0(A1).
Output graphic information about the design object (drawings) is also printed on plotters in large format. Paper feeding method plotters like scanners, there are roll (Fig. 2.2, b) or flatbed. According to the method of applying the coloring matter - laser or inkjet. The question of what should be an engineering drawing, black and white or color, has recently been unequivocally decided in favor of color. Firstly, in view of the significant progress in the field of color printing, which has become slightly more expensive than black and white. Secondly, the color carries Additional information about the object being designed and helps to increase the efficiency of visual analysis of such drawings.
SHAPE\* MERGEFORMAT
Rice. 2.2. a) Roll scanner; b) Roll plotter
TO peripherals computers can also include devices digital photo and videos, which are now widely used in the collection of input data for road design.
For the organization of collective work on the project and the rapid exchange of information, computers are combined into local (intranet) and global (Internet) networks, the technical components of which are servers, network cards, modems, fiber optic networks, etc.
Software CAD is divided into system-wide And applied.
System-wide software includes, first of all, operating systems (OS), which control all the processes that occur in computers. The emergence and evolution of the OS took place in parallel with the development of the computers themselves. If the creation of the first personal computer is associated with the company IBM(www. ibm. com ), then the first mass OS appeared for this computer from the company Microsoft( www. microsoft. com) and was called MS- DOS.
14-year path of evolution (from 1981 to 1995) MS- DOS versions 1.0-7.0 contributed to the introduction of computers from solving narrow engineering problems to their widespread use in all spheres of life.
From the beginning of the 90s to replace MS- DOS comes Windows(from English - windows) also from the company Microsoft, which allows you to work with several programs (windows) at the same time, easily switching between them without having to close and restart individual programs. At the initial stage of development Windows acted as a graphical interface for MS- DOS.
With the release Windows 3.1 (1992) this operating system is associated as an independent one, capable of working with more than 640 kb of RAM, with scalable fonts true type.
Released in 1993 WindowsNT(short for New Technology - new technology) has been well received by developers due to its increased security, stability and advanced API-interface Win32 , which simplifies the compilation of powerful programs.
In 1995 comes out Windows95 – the most user friendly version Windows, for installation which does not require pre-installation DOS; its appearance makes the PC more accessible to the mass consumer. Windows 95 has a built-in set of protocols TCP/ IP and long filenames are allowed.
Windows 98 (1998) - latest version Windows on the basis of the old kernel, functioning on the foundation DOS. System Windows 98 browser integrated Internetexplorer 4 and is compatible with numerous new hardware standards, including USB ports. Subsequent versions of Windows were developed based on the NT kernel.
At present (since 2001), most of the application programs, including CAD, operate under the control of the operating system MSWindowsXP(from English eXPerience - experience).
New domain-specific interface MSWindowsXP allows you to quickly master the principles of working with the operating system, even for those users who have never previously encountered systems of the family Windows. Applied in WindowsXP advanced web technologies open up the possibility of exchanging text and voice messages, creating web projects of various levels of complexity and sharing applications not only on the local network, but also on the Internet.
Conditionally system-wide software includes MSoffice, a number of applications of which (text editor Word, spreadsheets excel) have become de facto standards in their class of programs. Almost all CAD systems that generate as output text documents, do it in the environment MSWord, and tabular forms - in the environment MSexcel.
Application programs, in addition to the CAD itself, include: vectorizers; programs for processing geodetic data, remote sensing data; database management systems (DBMS); design documentation management systems (CDMS), etc.
The last of these (QMS) are extremely important in the work of design organizations, since they largely ensure the functioning of quality control systems in the production of design products.
Of the many programs of this class, the most fully functional system is PartyPLUS(developer - Lotsia Soft company, Moscow, www. lotia. com ).
PartyPLUS is a professional system built in the "client-server" architecture based on the DBMS type Oracle, MSSQL- server, Sybase and distinguished by reliability, performance, scalability and security.
Rice. 2.3. Party PLUS Document Management System
The system contains a secure archive of documents, as well as built-in tools for free and predefined routing of documents, work and business process management. The system supports the mode of parallel collective work of various user groups and provides management of all information related to the project, which allows employees of the design organization not only to access the description of the project, but also to manage information about this project.
If the enterprise has several geographically distributed design departments, then with the help of PartyPLUS you can organize well-functioning interaction of remote departments when working on several projects.
PartyPLUS has the function of keeping a history of all engineering changes in the project structure, the ability to compare the current state with the state on any date. There are support tools for multivariant design with storage of options that are not included in the main project, support tools for working with document versions. It is possible to set analogues or related elements for a project element, group elements according to various criteria.
System PartyPLUS is universal, maximally flexible for solving problems in various branches of engineering activity, including the road industry, and is focused on equal work with various CAD systems.
2.2. Mathematical and methodological support
Mathematical support is a set of analytical and numerical methods, mathematical models and algorithms for performing design procedures. The use of certain methods depends on the level of development of CAD, the properties of design objects and the nature of the tasks being solved.
At the initial stage of CAD development, manual design methods were algorithmized. This contributed to a reduction in design time, but the quality of design solutions practically did not improve.
The first work in the field of optimizing design solutions began in the 70s and was associated primarily with the design of a longitudinal profile. The works of E.L. Filshtein and his method of "boundary iterations", V.I. Struchenkov and his method of "gradient projection" established the position of the design line of the longitudinal profile, taking into account the minimization of earthworks. Already at this stage, it was necessary to abandon the presentation of the design line in the form of a sequence of straight lines and arcs of circles, and switch to the model of the design line in the form of a broken line (linear spline). However, these methods did not affect the general (basic) principles of surveying and designing highways.
The transition in the 90s to system automation of road design based on digital terrain models led to a significant change in the entire technology of design and survey work.
During the period of "manual" design of roads, geodetic surveys were carried out using the "picket" method. The essence of this method is the following stages of work:
· Field tracing of the road. At the same time, the tangential course of the route is at the same time the main course for all subsequent marking works, both at the survey stage and at the construction stage.
· Planned-high-altitude fixing of the route with roadside benchmarks and corner posts.
· Breakdown of picketage along the route. Not only picket points are broken and fixed, but also positive (characteristic) points associated with relief breaks, the intersection of water flows, utilities and roads.
· Double longitudinal geometric leveling of the route according to the accepted stationing.
· Shooting cross sections. When staking out the picketage along the route, the cross sections are simultaneously staked out at all picket and plus points. On straight sections of the route, the cross-sections are broken perpendicular to the axis of the road, and on curved sections - perpendicular to the tangent to the route. The length of the diameter is taken such that the subgrade with all its structural elements is located within it.
Cross-sectional surveys are carried out to build longitudinal and transverse profiles along the accepted route for the subsequent design of the subgrade, the organization of a surface drainage system, the calculation of the volume of earthworks and the preparation of project documentation.
As follows from the above, with the "picket" survey method, changing the position of the route and, consequently, all other projections at the design stage is not possible. Thus, the creative beginning of the design activity with this method is limited due to the predetermined position of the road route, which significantly affects the quality of the final design solutions. We also note that in the field conditions of tracing, in the absence of computer equipment, the survey engineer was limited to an elementary rounding scheme of the route of the "clothoid-circular curve-clothoid" type, which could be broken down according to the corresponding breakdown tables.
A completely different perspective is opened by the "picket-free" method of road surveys, the priority application of which became possible thanks to the achievements of electronic tacheometry and computer technology.
Research on this method consists of the following:
· In the band of possible design solutions, determined at the pre-design stage, the main passage (network of passages) is laid and fixed.
· A tacheometric survey of the band of variation is carried out. At the same time, high productivity of work is ensured, since all measurements necessary to determine the spatial coordinates of the survey points of the terrain are performed in a complex using one geodetic instrument - a tacheometer.
· From the electronic tacheometer, a digital terrain model is read into the computer, which is the basis for all subsequent design procedures.
Note that with the "picket-free" survey method, the location of the route is determined not at the survey stage, but at the design stage (in office conditions). This makes it possible to vary the location of the route at almost any stage of design, to use the most modern mathematical methods, including optimization ones, to determine the location of the route and its description.
Given the three-dimensional nature of the DSM and the surfaces generated by it, a unique opportunity for spatial tracing of roads appears. Currently, the methodology and algorithms for spatial tracing are being successfully developed within the framework of CAD and should soon replenish the arsenal of advanced technologies for road design practice.
Of the many methods of computational mathematics that have become available in the conditions of system automation of design work, we will focus on splines and Bezier curves used in automated road tracing in plan and longitudinal profile.
interpolation splines. As you know, the term "spline" comes from the name of a drawing tool - a thin metal or wooden ruler that bends so as to pass through given points ( x i, y i= f(x i)).
Then the spline in the equilibrium position takes a shape that minimizes its potential energy. And in the theory of beams it is established that this energy is proportional to the integral over the length of the arc from the square of the curvature of the spline:
under conditions S(x i) = y i.
Rice. 2.4. The outlines of the spline as a mathematical analogue of the ruler
Splines can be defined in 2 ways: based on the mutual agreement of simple functions and from the solution of the minimization problem.
The splines determined by the first method include interpolation splines, which are necessary for analytical representation discretely given information.
Smoothing splines are most often determined on the basis of the 2nd method. It is smoothing splines that should find the widest application for optimizing those design solutions that, at the initial stage of consideration, are, as a rule, approximate.
In design practice, as a rule, splines of the 1st and 3rd degree are used. Splines of the 1st degree (linear) serve, firstly, as a good and accessible illustration for understanding the processes of constructing spline algorithms, and secondly, they are sufficient to describe the geometric elements of roads represented as broken lines (main and tangential passages, longitudinal and transverse ground profiles, etc.).
Splines of the 1st degree. Splines of the 1st degree (broken lines) are quite simple for understanding, and the same, time, reflect the basic properties of spline functions. From a mathematical point of view, a spline of the 1st degree is a piecewise continuous function, described on each segment by an equation of the form:
y= a i+ b i x, (2.2)
where iis the number of the considered interval between interpolation nodesx i And x i + 1 .
As can be seen from formula (2.2), on the elementary interval the form of the equation does not differ from the generally accepted straight line expression. In general, the equation of a polyline (spline of the 1st degree) in matrix form can be written as:
(2.3)
This system of linear equations does not require a joint solution and breaks down into solutions of each equation separately. Spline, the solution of which is associated with the calculation of subsystems of small dimension, in this case– equations of the first order, we will call local.
An interpolation spline of the 1st degree is a polyline passing through points (x i , y i). For population x i(i = 0, 1,… ,n) in the interval [ a, b] in this case, the condition x i 1 .
Using the Lagrange polynomial, one can construct a spline for the interval i-(i + 1):
(2.4)
Designation S 1 (x ) will be understood as a spline function of the first degree. Otherwise, equation (2.4) can be written:
(2.5)
If we accept o, the form of equations (2.2) and (2.5) coincides. To build an algorithm and draw up a procedure for constructing and calculating a spline, you need to remember only 2 n+2 numbers.
Splines of the 3rd degree. Splines of the 3rd degree (cubic) is a piecewise continuous (continuity of the 1st and 2nd derivatives) function consisting of segments of cubic parabolas.
Currently, there are many algorithms for constructing and calculating cubic splines on a computer, which is due to their wide use in solving technical problems related to the interpolation of curves and surfaces.
When solving the problem, between n nodes there are n–1 fragments of cubic curves, and the cubic curve, in turn, is determined by 4 parameters. Since the value of the function and the 1st, 2nd derivatives ( Xs, X¢ s, X² s) are continuous in all ( n–2)-x internal nodes, then we have 3( n-2) conditions. in knots Xsi= X i n more conditions are imposed on Xs. From here we get 4 n-6 conditions. To uniquely define a spline, two more conditions are required, which are usually associated with the so-called boundary (boundary) conditions. For example, it is often taken simply. In this case, we obtain the required number of conditions for determining the natural spline in the form:
The disadvantage of this spline is that it does not have the ability to change shape in the area between two rigidly fixed interpolation points. Only by moving one of the interpolation points can some change in the shape of the spline curve be achieved. At the same time, due to the fact that the cubic interpolation spline refers to non-local methods of approximation, its values at points that do not coincide with the grid nodes Δ: a= x 0xN= b, depend on the totality of quantities fi = f(x i), i= 0, 1 ,…, N, and also on the values of the boundary conditions at the points a, b; therefore, the desired effect of reshaping the spline curve at one point in the interpolation interval may overlap unwanted changes on the rest of the segment.
However, methods of dealing with this unpleasant phenomenon are known. This is, firstly, the use of local Hermitian interpolations, for which the value of the spline on the interval between grid nodes depends on the values of the function and its derivatives only from some neighborhood of this interval.
Second, interpolation based on rational splines. Retaining one of the most important properties of cubic spline interpolation - simplicity and efficiency of computer implementation - rational splines have the ability to approximate functions with large gradients or breakpoints, while eliminating oscillations inherent in a conventional cubic spline.
A rational spline function is called a function S(x), which on each interpolation interval [ x i, x i+1 ] is written as
(2.7)
where t =(x-x i)/h i , h i = xi + 1 - x i ,p i ,qi– given numbers, -1 p i ,q i and is continuous together with its first and second derivatives.
It can be seen from expression (2.7) that for p i = q i = 0, i = 0, 1,…, N-1, the rational spline becomes a regular cubic spline. In addition, we can assume that the spline of the first degree is also a special case of the cubic spline, since for all p i , q i –>∞,i = 0, 1,…, N–1, fair S(x)–> fi(1– t)+ fi +1 t ,xÎ [x i ,x i +1 ].
Thus, it can be expected that when using rational splines, by an appropriate choice of free parameters p i , q i achieved high accuracy approximations in areas of sufficient smoothness of the interpolated function, and in areas with large gradients, the requirements of a qualitative nature - convexity and monotonicity - are satisfied.
The use of a rational spline function makes it possible to describe the trace with a uniform dependence with the maximum approximation to the trace given by traditional elements. Varying the values of the coefficients pi And q i , it is possible to fully simulate the traditional elements of the route plan (straight line, circular curve, clothoids) by the spline function.
The "weak" point in the justification of interpolation splines as a universal mathematical apparatus for tracing roads is the assumption (condition) that the interpolation nodes are correctly assigned by the designer and are not subject to correction when calculating the values of the spline itself.
Let's analyze how the location of the nodes is assigned in practice?
If tracing is performed on the basis of a map or topographical plan, then a sketch line of the road is drawn, which, in the opinion of the designer, is the most appropriate under given conditions, "by hand" or with the help of mechanical devices. Next, interpolation nodes are fixed on the sketch line and their coordinates are measured. At the same time, there are no strictly formalized algorithms for assigning the location of nodes, there are only a number of practical advice. In particular: the frequent arrangement of nodes leads to oscillations of the curvature of such a spline due to the inevitable error in capturing the coordinates of the interpolation nodes; their rare location causes significant deviations of the spline trace from the sketch line that generates it.
If tracing is performed based on field survey materials, then the spline interpolation nodes, in this case, are survey points of a digital terrain model, and the error in establishing their coordinates is even more obvious due to the presence of random and systematic errors.
A good approximation of the spline trace to the sketch version and, at the same time, its sufficient smoothness (smoothness) can be achieved, as a rule, only with multiple intuitive adjustments of the interpolation nodes by the designer.
It follows from this that interpolation splines are not a mathematical tool for optimal tracing, but only a convenient and, in many problems, extremely effective tools for computer processing of sketchy design solutions. The quality of such solutions essentially depends on the qualifications of the designer.
It follows from the above reasoning that the formulation of the tracing problem based on splines should assume the following: the interpolation nodes of the sketch route, and in the case of reconstruction, of the original route, are assigned approximately (with a tolerance) and their exact location is calculated according to certain patterns, taking into account a number of fundamental target settings of the tracing process. In mathematical terminology, this problem can be attributed to the problems of generating geometric shapes from their rough (approximate) descriptions or smoothing problems.
Smoothing splines. As a mathematical apparatus for solving the problem of tracing roads, smoothing splines are used, which minimize the functional of the form:
under restrictions, for example,
In the functional record q = 1, 2; S(x i) is a spline; r i is the weight coefficient of the interpolation node; f 0 (x i) is the initial approximation function.
The restrictions can be very different, and in the case of tracing roads, these are: restrictions on the permissible radius, the direction of the route in the plan and the slope in the longitudinal profile, etc. At the same time, for splines of the third degree, the so-called "boundary conditions" must be added at points x 0 = a ,x n =b, which ensure the uniqueness of the construction of the spline. For example, these can be the conditions for a given initial and final direction of the designed section of the route S¢ (x a), S¢ (xb).
It follows from the form of writing joint conditions (2.8) - (2.10) that this is a problem of conditional optimization.
Condition (2.9) allows one to shift the interpolation nodes in the established variation corridor according to a given algorithm. The sign of completion of the iterative optimization process is the fulfillment of condition (2.10) and means that at each further iterative step the shift of any of the nodes will not exceed the value d.
If in condition (2.9) ei= 0, then again we come to the concept of interpolation splines. From here it becomes obvious that interpolation splines are just a special case of smoothing splines.
The choice of smoothing splines for further detailed consideration only in the form of algebraic polynomials and only of the 1st and 3rd degree from the whole variety is due to the fact that these are the simplest splines in computer implementation and, at the same time, have sufficient approximative properties for describing outlines trace and its differential analysis. In the case of 1st degree splines, this analysis (1st and 2nd derivatives) can be performed as divided differences, and for 3rd degree splines, by direct differentiation of the function.
Functional (2.8) well models the problem of tracing roads during their reconstruction, which consists in achieving a minimum deviation of the designed route from the existing one, while simultaneously providing for the slope and curvature in the longitudinal profile, and for the curvature and rate of curvature increase in the plan according to the requirements of SNiP for this road category. The minimum deviation is achieved due to the second term, and the conditions for curvature and slope - the first term of the functional (2.8).
When two terms are jointly minimized, the relation between them is controlled by the weight coefficients r i , which must be normalized in a certain way.
Let us consider the optimization possibilities of the functional (2.8) in order of increasing complexity.
The second term of the functional
known as the method of least squares, and it is a function n+1st variable S(x i), i = 0, 1,…, n. The minimization of the latter decomposes in this case into the minimization of individual terms independently for each variable.
In the case of using splines of the 1st degree, the first term of the functional (2.8) will be written as
.(2.12)
Consider a linear approximation of the arc length functional of the curve
(here it is assumed that | S`(x)| few). Obviously, the solution of the problem of minimizing the functional (2.13) coincides with the solution of the linearized problem of finding an element of minimum length. The resulting solution is often called a spline in a convex set.
After substituting the first derivative of the spline, which in this case coincides with the divided difference, it will take the form
(2.14)
where h i= x i +1 –x i.
Differentiate with respect to the variable S(x i) and add two consecutive terms of the equation containing this unknown:
Equating the resulting sum to zero and expressing the unknown S(x i), we get
Here the "=" sign represents the assignment operator. If we take the interpolation step uniform, that is, h i =const, then the optimization process (step by step iterations) in the graphical interpretation will be quite clear (Fig. 3. 10).
The rapid convergence of the iterative process makes it possible to recommend this method for the preliminary development of design solutions for the design line of the longitudinal profile. In this case, the radius of curvature and the slope of the design line can be controlled by plotting the first and second divided differences.
Rice. 2.5. Graphical interpretation of linear spline smoothing
Joint consideration of the sum of functionals (2.12) and (2.14) gives us a recursive formula for optimization:
The convergence of the iterative process here, in comparison with formula (2.17), is lower and essentially depends on the quantity r i. Weight coefficient r i allows you to slow down or speed up the iterative process at individual points (nodes) and can, for example, for a project line, serve as a means of accounting for the volume or cost of building a subgrade (road works) on a section of unit length.
Consider the first term of functional (2.8) as applied to cubic splines:
Similarly, the solution of the spline problem in a convex set describes (in a linearized formulation) the position occupied by an elastic bar in the constraint corridor. When the second derivative is replaced by the second divided difference, this functional will take the form:
where S¢ (x a), S¢ (xb) are one of the possible boundary conditions for a cubic spline. In relation to the design line, this is the slope in the initial ( x a) and final ( xb) points of the projected section of the road.
Differentiation and summation of equations will give us the corresponding recurrent formulas, which are detailed in the special literature.
The design of road curves in plan according to the classical scheme "clothoid - circular curve - clothoid" is quite reasonable from a theoretical standpoint, but in practice such a scheme has many flaws and inconveniences. Without going into their essence, we note that if we apply any function that could alone to some extent model the classical scheme (composite curve), then from the standpoint of the convenience of algorithmization and the organization of the "engineer-computer" dialogue, this would be enough effectively.
Bezier curves. In 1970 Pierre Bezier (French mathematician) selected the components of the parametric cubic polynomial in such a way that their physical meaning became very clear and very suitable for solving many applied problems, including for the purposes of designing roads according to the "tangential tracing" principle.
The Bezier formula for the cubic polynomial ( n= 3) has the following form.
Let be r i = , i= 0, 1, 2, 3, then for 0 ≤ t≤ 1:
or in matrix form:
The matrix M is called the basis matrix of a cubic Bezier curve.
Curve, represented in Bezier form, passes through points r 0 and r 3 , has a tangent at the point r 0 , directed from r 0 to r 1 , and the tangent at the point r 3 directed from r 2 k r 3 .
Direct R 0 R 1 , R 1 R 2 and R 2 R 3 form a figure called the characteristic (defining) broken line, which predetermines the outlines of the Bezier curve (Fig. 2.6).
To draw a curve, specify points R 0 and R 3 through which the curve should pass, then on the desired tangents to this curve at points R 0 and R 3 set points R 1 and R 2. Changing the length of the segments R 0 R 1 and R 2 R 3 vary the outlines of the curve, giving it the desired shape.
Rice. 2.6. Segment of a cubic bezier curve
The main controlled quantity in the design of curves in the plan is the radius of curvature. In order to calculate the radius of curvature at each point of the curve, it is necessary to know the values of the first and second derivatives of the radius-vector of the point. For a cubic Bezier curve, the first and second derivatives are calculated using the formulas below:
Then the curvature (the reciprocal of the radius of curvature) is calculated by the formula:
In addition to the 3rd order (cubic) Bezier curve, 2nd, 4th and 5th order Bezier curves can also be used for road tracing purposes. The corresponding formulas for calculating the radius vectors (and their derivatives) for these curves are given below.
2nd Order Bezier Curve:
4th order bezier curve:
Bezier curve 5th order:
The union of elementary Bezier curves γ (1) , γ (2) ,…, γ ( l) , for which the end point of the curve γ ( i) , i= 1, 2,…, l - 1 coincides with the initial point of the curve γ ( i+1) , you get a composite Bezier curve. If each curve γ ( i) is given by a parametric equation of the form
r = r (i) (t), 0 ≤ t≤ 1,
then this condition is written as follows:
r (i) (1) = r (i +1) (0), i= 1, 2,…, l–1.
In particular, in order for the tangent of a compound Bezier curve defined by a set of points P 0 , P 1 , …, P m , changed continuously along this curve, it is necessary that the triples of vertices P 3 i -1 , P 3 i, P 3 i +1 (i≥ 1) were collinear, that is, they lay on the same straight line (see Fig. 2.7).
Rice. 2.7. Compound cubic bezier curve
Spatial Bezier curves. Above, in the discussion about Bezier curves, the flat location of the trace reference points was understood and, accordingly, the representation of only flat curves was considered. In the general case, the reference points of the characteristic Bezier polyline are given by the points of the three-dimensional space Pi(x i, y i, z i), i= 0, 1 ,…, m.
Then the spatial Bezier curve of degree m is determined by an equation that has the following form:
where are the Bernstein polynomials.
The matrix notation of the parametric equations describing the spatial Bezier curve has the form:
0≤ t ≤ 1,
A more detailed presentation of the spatial tracing of roads is given in Ch. five.
Methodological support - a set of methodological materials that contribute to the functioning of CAD.
Professional CAD systems usually have methodological support in the form of "Reference Guides" in paper form. The main menu of such systems also contains a section Help (Help), which provides a description of the main design procedures.
During the operation of CAD, experience is accumulated in the rational development of design solutions based on the totality of the system's tools. This experience, as a rule, is presented in the form of "practical guides (manuals)" and contributes to improving the efficiency and quality of engineering work.
2.3. Information and organizational support
Information Support is a set of tools and methods for building an information base for design purposes.
The information support includes: state standards(GOST), building codes (SN), building codes and regulations (SNiP), departmental building codes (VSN), standard design solutions for structures and elements of highways. All of the above regulatory and information materials exist in paper form or in the form of electronic counterparts.
Another part of the information support exists only in electronic form and is an integral part of CAD. These are libraries of conventional signs (see Fig. 2.8), classifiers and codes, templates of typical elements as part of graphic algorithms.
Rice. 2.8. Library symbol for a topographic plan
Regional information is also used in the design process. It includes information of a meteorological and ecological nature, data on the relief and geological structure of the area, information on the location of quarries of soil and stone materials, etc.
According to another classification, information can be divided into input, intermediate and output. Input - a set of initial data necessary for making a design decision. Intermediate - previously obtained as a result of solving some problems and used to solve others, but not the final results of solving problems. Output - obtained as a result of solving problems and intended for direct use in design.
Organizational support is a set of organizational and technical measures aimed at improving the efficiency of CAD. These include: changing the organizational structure of the design organization, its departments and divisions; redistribution of functions between departments; change in the technology of design and survey work and personnel composition, advanced training of designers in the field of CAD, organization and functioning of quality management systems for design products based on international standards ISO 9001:2000.
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2.1. PC hardware
2.2. PC memory
2.1. PC hardware
All hardware of a modern personal computer
are divided into three components:
1) information input devices;
2) information output devices;
3) a device for processing and storing information, called
system block.
Input devices are any devices that
which information is entered into the computer. These include: keyboard,
mouse, disk drives, CD-ROM drives, trackballs, pointers, etc.
A trackball is a ball built into a keyboard that is different
from the mouse so it does not need to be moved around the work surface.
The pointer is an analogue of the joystick and is placed on the keyboard.
Trackballs and pointers are most commonly used in portable
computers, and in pocket computers for these purposes is used
touch screen.
Information output devices include: display, all types
printers, disk drives, etc.
Other devices can also be connected to the computer, for example:
7) modem - a device for exchanging information with others
computers through telephone network; the basis of this process is
converting data received from the processor from digital form to
high-frequency analog signal;
8) scanner - a device for creating a digital copy of an image
any object;
9) graphics tablet - a device for input contour
images and graphics.
In addition, you can also list various manipulators, among
which: joysticks, steering wheel. Ionizers are also connected to the computer,
heating pads, mini-refrigerators that use a computer as
power source.
Also, uninterruptible devices are often used.
power supplies that ensure the safety of the computer during sudden surges
voltage or power off. In an uninterruptible device
power supply is a voltage stabilizer, built-in rechargeable
batteries and alternator. In the event of a power failure, this unit
switches the voltage on itself and for some time provides
computer energy, which determines its stable operation. This device
capable of maintaining normal PC power for 3 to 20 minutes.
Audio adapters are used for playback, recording and processing
sound, such can be sound cards and sound cards. Device data
convert computer digital data into analog audio signal and
back; The sound card hosts several different devices that
allow you to create a recording studio based on a PC. To the main features
audio adapters include: bit depth, number of playback channels (mono
or stereo), the synthesis principle used, extensibility and compatibility.
From the view sound cards and speakers also depends on the sound quality.
Sufficient sound quality is provided by any active speakers, and
better sound is achieved by connecting an audio card to the input
home audio amplifier.
Let us dwell in more detail on the study of the third group of hardware
funds, that is, the system unit. The main element of the system unit
is the system board. It is also called the main or motherboard, in
documentation, it is denoted by the abbreviation MB.
The motherboard plays a significant role, since its characteristics
much depends on the work of the PC. There are several types of motherboards,
which are usually designed for specific microprocessors. Choice
system board largely determines the possibility of future upgrades
computer. When choosing a motherboard, consider the following:
characteristics:
Possible types of microprocessors used, taking into account their working
Number and type of system bus connectors;
Base fee;
Possibility of increasing RAM;
Upgradable basic system I/O (BIOS).
All microcircuits located on the system board are connected at
using the system bus. The system bus is designed to transmit
information between the processor and the rest of the PC components. Via
bus, both the exchange of information and the transfer of addresses, service
signals. Peripherals are also connected to the system bus
using controllers and adapters (these are such special boards).
The system board contains:
1. Central processor. The processor is not accidentally considered the heart
or the basis of a computer, since it is from it that to a large extent
depends on the performance of the entire system.
A processor is a microchip that performs
arithmetic, logical and control operations specified by the program
in machine code.
The main characteristics of the processor are:
The capacity of internal registers (devices for recording, storage and
reading numbers in binary code);
Bit depth of the data bus and address bus;
Values of internal and external clock frequencies;
The design of the connector.
2. RAM.
3. Super-fast or cache memory (in modern computers
is already integrated into the processor).
4. The BIOS chip is the basic system for input and output of information,
which is a non-volatile memory chip in which
BIOS codes written.
Basic input-output system (Basic Input Output System - BIOS)
is, on the one hand, an integral part of the hardware, on the other -
one of the OS software modules. The origin of this name is associated with
The fact that the BIOS includes a set of I / O programs. With these
OS programs and application programs can interact with both
various devices of the computer itself, and with peripheral
devices.
As an integral part of the hardware, the BIOS system in the PC is implemented
in the form of a single microcircuit installed on the computer motherboard.
Most modern video adapters and storage controllers have
its own BIOS, which supplements the system BIOS.
It has the following main functions:
1) start loading the operating system;
Performing a test check of all
critical hardware and system components;
Provision of a special program for configuration and installation
BIOS settings and PC hardware configuration.
The main task of the BIOS is to initialize the connected to it
devices. Immediately after the computer is powered on, the BIOS checks
operability of devices, sets low-level parameters of their operation,
after which it searches for the bootloader of the operating system on available media
information and transfers control to the operating system. Wherein
the operating system in the course of work can change most of the settings,
originally set in the BIOS.
That is, as an OS software module, the BIOS system launches the program
computer power-on test POST (Power On self test –
power-on self-test). When starting this
programs test the main components of the computer (processor, memory
and etc.). If you have problems powering up your computer, i.e. the BIOS does not
can execute the initial test, the error message will look like
sequence of sound signals.
5. Chipset - a set of control chips. Also included here are
auxiliary microcircuits and information input/output controllers. Everything
auxiliary chips on the motherboard are divided into two groups,
called the north and south bridges. Northbridge provides
connecting the processor to the RAM and video card. south bridge
responsible for connecting other devices.
6. Expansion connectors, that is, slots. It is in them that they connect
additional devices such as (TV)TV tuners, modems,
sound cards.
2.2. PC memory
Computer memory is divided into internal and external. Internal
memory, in turn, is also divided into two types - permanent and
operational. Read Only Memory or Read Only Memory
(ROM) is used to permanently store information when the PC is turned off
information is not deleted. This memory stores the operating system, system programs, and
user data.
Random Access Memory or Random Access Memory (RAM) –
PC brain. It serves for temporary storage of information. This device,
where data and results are placed during program execution
processing. When the computer is turned off, the contents of RAM
is erased.
The computer's RAM is made up of:
1) main (it accounts for more memory);
2) cache memory;
3) memory chips on expansion boards.
As for external memory, it is used to save
PC results. The most common external memory of a PC is
these are flash cards or flash drives, laser discs, as well as floppy drives
magnetic disks (i.e. floppy disks) and a hard disk drive (i.e.
"Winchester").
All these devices allow you to transfer documents and programs from
one computer to another, store information not used
permanently on the computer, make archival copies of the information contained
on the hard drive.
Floppy drives are used to write and read information from floppy disks.
However, due to their insufficient reliability and small volume, this type of
devices have not been used in recent years.
The most convenient and mobile, and therefore popular in recent
time are considered flash cards.
2.3. PC software
Computer software is a collection of programs
procedures and instructions, as well as related technical documentation,
allowing the use of computers to solve specific problems.
By field of application computer software
subdivided into systemic and applied.
Application software is a special
programs that are used in solving certain practical
tasks. Currently, programmers have developed many applications
programs used in mathematics, accounting and other fields of science.
System, or general, software acts as
"organizer" of all computer components, as well as those connected to it
external devices.
Thus, system software is a complex
programs without which the computer cannot work at all or loses
some important properties.
System software is essential for trouble-free
computer operation, prevention of personal computer equipment,
copying, restoring files, archiving
documents, as well as to organize the reliable operation of other programs.
The system software consists of two
Components:
1) operating system - a whole complex of control programs,
which are the interface between PC components and provide
the most efficient use of computer resources. Operating system
loaded when the computer is turned on;
2) utilities - auxiliary maintenance programs.
Utilities include:
Programs for diagnosing a computer - check the configuration
computer and the performance of its devices;
Disk optimization programs - provide faster
access to information stored on the hard drive through optimization
placing data on it. The process of optimizing data on the hard drive
better known as the disk defragmentation process;
Disk cleanup programs - find and remove unnecessary
information (eg. temporary files, temporary internet files,
files located in the basket, etc.);
Disk cache programs - speed up access to data on the disk by
organization in the RAM of a computer cache buffer containing
the most frequently used parts of the disk;
Dynamic disk compression programs - increase the volume
information stored on hard drives by dynamically compressing it.
The actions of these programs are not noticeable to the user, they appear
only through increasing the capacity of disks and changing the speed of access to
information;
Packagers (or archivers) - pack data into
hard drives through the use of special methods of information compression.
These programs allow you to free up significant disk space by
information compression;
Antivirus programs - prevent computer infection
virus and eliminate its consequences;
Programming systems - a set of programs for automation
the process of programming scenarios for the operation of a computer.
2.4. The concept of the operating system (OS), its functions
The operating system of a computer is a collection of software
tools designed to directly control the work
computer and all its hardware resources.
The main functions of the operating system can be listed
the following:
1 memory management;
2 I/O control;
3 file system management;
4 process interaction management;
5 process dispatching;
7 accounting for the use of resources;
8 command language processing.
The operating system hides from the user complex and unnecessary
details of the operation of the computer processor and presents it with a convenient
interface for work, that is, a way to communicate with a computer.
The most common operating systems
families WINDOWS, Linux.
