What do computers and computers have in common? General information about computers and computing systems
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Electronic Calculating machine is a complex of technical and software, designed to automate the preparation and solution of user tasks. The user is understood as a person in whose interests data is processed on a computer.
Structure is a collection of elements and their connections. There are structures of technical, software and hardware-software tools.
Computer architecture- this is a multi-level hierarchy of hardware and software from which a computer is built. Each level allows for multiple construction and application. The specific implementation of the levels determines the features of the structural design of the computer.
Various categories of computer specialists are engaged in detailing the architectural and structural design of a computer. Circuit engineers design individual technical devices and develop methods for interfacing them with each other. System programmers create hardware control programs, information interaction between levels, organization of the computing process. Application programmers develop software packages for more than high level, which provide interaction between users and computers and the necessary services when they solve their problems.
The structure of the computer is determined by next group characteristics:
· technical and operational characteristics of the computer (speed and performance, indicators of reliability, reliability, accuracy, capacity of RAM and external memory, overall dimensions, cost of hardware and software, operating features, etc.);
characteristics and composition functional modules basic computer configuration; the possibility of expanding the composition of hardware and software; possibility of changing the structure;
· composition of computer software and services(operating system or environment, application software packages, programming automation tools).
The main characteristics of the computer include:
Performance This is the number of commands executed by a computer in one second.
Comparison of the performance of different types of computers does not provide reliable estimates. Very often, instead of the performance characteristic, the associated performance characteristic is used.
Performance This is the amount of work performed by a computer per unit of time.
Relative performance characteristics also apply. To evaluate processors, Intel has proposed a test called the iCOMP index (Intel Comparative Microprocessor Performance). When determining it, four main aspects of performance are taken into account: working with integer numbers, floating point, graphics and video. Data has 16- and 32-bit representation. Each of the eight parameters participates in the calculation with its own weighting coefficient, determined by the average ratio between these operations in real problems. According to the iCOMP PM index, Pentium 100 has a value of 810, and Pentium 133-1000.
Storage capacity. Memory capacity is measured by the number of structural units of information that can be simultaneously in memory. This indicator allows you to determine what set of programs and data can be simultaneously placed in memory.
The smallest structural unit of information is bit- one binary digit. As a rule, memory capacity is measured in larger units of measurement - bytes (a byte is equal to eight bits). The following units of measurement are 1 KB = 210 = 1024 bytes, 1 MB = 210 KB = 220 bytes, 1 GB = 210 MB = 220 KB = 230 bytes.
The capacity of random access memory (RAM) and the capacity of external memory (VRAM) are characterized separately. This indicator is very important for determining which software packages and their applications can be processed simultaneously in the machine.
Reliability This is the ability of a computer, under certain conditions, to perform required functions within a given period of time (ISO (International Standards Organization) standard 2382/14-78).
The high reliability of a computer is built into the process of its production. The use of very large-scale integrated circuits (VLSI) dramatically reduces the number of integrated circuits used, and therefore the number of their connections to each other. The modular design principle makes it easy to check and monitor the operation of all devices, diagnose and troubleshoot problems.
Accuracy this is the ability to distinguish between almost equal values (ISO standard - 2382/2-76).
The accuracy of obtaining processing results is mainly determined by the bit capacity of the computer, as well as the structural units used to represent information (byte, word, double word).
Credibility this is the property of information to be correctly perceived.
Reliability is characterized by the likelihood of obtaining error-free results. The specified level of reliability is ensured by the hardware and software control tools of the computer itself. Methods for monitoring reliability are possible by solving reference problems and repeating calculations. In especially critical cases, control decisions are carried out on other computers and the results are compared.
The following classification of computers is possible:
– computer according to the principle of operation;
– Computers by stages of creation;
– computer for its intended purpose;
– Computer in size and functionality.
Classification of computers according to the principle of operation. Electronic computer, computer - a set of technical means intended for automatic processing information in the process of solving computational and information problems.
Based on the principle of operation, computers are divided into three large classes:
analog (AVM),
digital (DVM)
hybrid (HVM).
The criterion for dividing computers into these three classes is the form of presentation of information with which they work.
Digital computers (DCMs) are discrete computers that work with information presented in discrete, or rather, digital form.
Analog computers (AVMs) are continuous computers that work with information presented in continuous (analog) form, i.e. in the form of a continuous series of values of any physical quantity(most often electrical voltage). AVM machines are very simple and easy to use; programming problems for solving them is, as a rule, not labor-intensive; the speed of problem solving varies at the operator's request and can be made as high as desired (more than that of a digital computer), but the accuracy of problem solving is very low (relative error 2–5%). On a digital computer, it is most effective to solve mathematical problems containing differential equations, not requiring complex logic.
Hybrid computers (HCM) are computers of combined action that work with information presented in both digital and analog forms; they combine the advantages of AVM and TsVM. It is advisable to use GVM to solve problems of controlling complex high-speed technical complexes.
Digital computers with electrical representation are the most widely used. discrete information- electronic digital computers, usually called simply electronic computers(computers), without mentioning their digital nature.
Classification of computers by stages of creation. According to the stages of creation and the element base used, computers are conventionally divided into generations:
1st generation, 50s: Computers based on electron vacuum tubes;
2nd generation, 60s: discrete computers semiconductor devices(transistors);
3rd generation, 70s: Semiconductor computers integrated circuits with a low and medium degree of integration (hundreds, thousands of transistors in one package);
4th generation, 80s: Computers based on large-scale and ultra-large-scale integrated circuits-microprocessors (tens of thousands - millions of transistors in one chip);
5th generation, 90s: Computers with many dozens of parallel working microprocessors, allowing to build effective knowledge processing systems; Computers on ultra-complex microprocessors with a parallel-vector structure, simultaneously executing dozens of sequential program commands;
6th and subsequent generations: optoelectronic computers with massive parallelism and neural structure - with distributed network a large number (tens of thousands) of simple microprocessors that model the architecture of neural biological systems.
Each subsequent generation of computers has significantly better characteristics compared to the previous one. Thus, computer performance and the capacity of all storage devices increase, as a rule, by more than an order of magnitude.
Classification of computers by purpose. According to their purpose, computers can be divided into three groups:
– universal (general purpose),
– problem-oriented
– specialized.
Universal computers are designed to solve a wide variety of technical problems: economic, mathematical, information and other problems characterized by the complexity of algorithms and a large volume of processed data. They are widely used in shared computing centers and other powerful computing systems.
Problem-oriented computers are used to solve a narrower range of problems associated, as a rule, with the management of technological objects; registration, accumulation and processing of relatively small amounts of data; performing calculations on relatively simple algorithms; they have limited hardware and software resources compared to mainframe computers. Problem-oriented computers include, in particular, all kinds of control computer systems.
Specialized computers are used to solve a narrow range of problems or implement a strictly defined group of functions. Such a narrow orientation of computers makes it possible to clearly specialize their structure, significantly reduce their complexity and cost while maintaining high performance and the reliability of their work. Specialized computers include, for example, programmable microprocessors special purpose; adapters and controllers that perform logical functions for controlling individual simple technical devices, units and processes, devices for coordinating and interfacing the operation of computer system nodes.
Classification of computers by size and functionality. Based on size and functionality, computers can be divided into:
· extra-large (supercomputers),
· large (Mainframe),
· ultra-small (microcomputers).
Personal computers can be classified according to standard sizes. Thus, there are desktop (desktop), portable (notebook), pocket (palmtop) models. More recently, devices have appeared that combine the capabilities of pocket personal computers and mobile communication devices. In English they are called PDA, Personal Digital Assistant. Taking advantage of the fact that no name has yet been assigned to them in the Russian language, they can be called mobile computing devices (MCDs).
Tabletop models are the most widespread. They are part of the workplace. These models are easy to reconfigure by easily connecting additional external devices or installing additional internal components. The sufficient dimensions of the desktop case make it possible to perform most of such work without the involvement of specialists, and this allows you to configure the computer system optimally to solve exactly the tasks for which it was purchased.
Portable models convenient for transportation. They are used by businessmen, merchants, heads of enterprises and organizations who spend a lot of time on business trips and moving. You can work with a laptop computer when you don’t have a desk. The particular appeal of laptop computers is that they can be used as a means of communication. By connecting such a computer to the telephone network, you can establish data exchange between it and central computer your organization. This is how messages are exchanged, orders and instructions are transmitted, commercial data, reports and reports are received. For use in the workplace laptop computers not very convenient, but they can be connected to desktop computers, used permanently.
Pocket models perform the functions of “smart notebooks”. They allow you to store operational data and get quick access to it. Some pocket models have a hard-wired software, which makes it easier direct work, but reduces flexibility in choosing application programs,
Mobile computing devices combine the functions of pocket computers and mobile communications devices (cellular radiotelephones). Their distinctive feature is the ability mobile work with the Internet, and in the near future the ability to receive television broadcasts. Additionally, the IDP is equipped with infrared communication means, thanks to which these handheld devices can exchange data with desktop PCs and with each other.
Multi-user microcomputers are powerful microcomputers equipped with several video terminals and operating in time-sharing mode, which allows several users to work effectively on them at once.
Personal computers (PCs) are single-user microcomputers that meet the requirements of general accessibility and universality of use.
Work stations are single-user powerful microcomputers specialized for performing certain type works (graphic, engineering, publishing, etc.).
Servers are multi-user powerful microcomputers in computer networks dedicated to processing requests from all network stations.
Of course, the above classification is very conditional, because a powerful modern PC, equipped with problem-oriented software and hardware, can also be used as a full-fledged work station, both as a multi-user microcomputer, and as a good server, its characteristics almost not inferior to small computers.
Classification by level of specialization. Based on the level of specialization, computers are divided into universal and specialized. On the basis of universal computers, it is possible to assemble computer systems of any composition (the composition of a computer system is called a configuration). For example, the same personal computer can be used to work with texts, music, graphics, photo and video materials.
Specialized computers are designed to solve a specific range of problems. Such computers include, for example, on-board computers of cars, ships, airplanes, and spacecraft. Computers integrated into household appliances, e.g. washing machines, Microwave cookers and VCRs are also specialized. On-board computers control orientation and navigation aids, monitor the state of on-board systems, perform some automatic control and communication functions, as well as most functions for optimizing the operating parameters of an object’s systems (for example, optimizing the fuel consumption of an object depending on specific traffic conditions). Specialized minicomputers focused on working with graphics are called graphics stations. They are used in the preparation of films and videos, as well as advertising products. Specialized computers that connect enterprise computers into one network are called file servers. Computers that ensure the transfer of information between various participants in the worldwide computer network are called network servers.
In many cases, with the tasks of specialized computer systems Ordinary universal computers can also cope, but it is believed that the use of specialized systems is still more effective. The criterion for assessing efficiency is the ratio of equipment productivity to its cost.
Classification by compatibility. There are many different types and types of computers in the world. They are produced by different manufacturers, assembled from different parts, and work with different programs. In this case, the compatibility of different computers with each other becomes a very important issue. Compatibility determines the interchangeability of components and devices intended for different computers, the ability to transfer programs from one computer to another, and the ability of different types of computers to work together with the same data.
Hardware compatibility. Based on hardware compatibility, so-called hardware platforms are distinguished. In the field of personal computers today, the two most widely used hardware platforms are the IBM PC and the Apple Macintosh. In addition to them, there are other platforms, the prevalence of which is limited to certain regions or certain industries. Computers belonging to the same hardware platform increases compatibility between them, while belonging to different platforms decreases compatibility.
In addition to hardware compatibility, there are other types of compatibility: compatibility at the operating system, software compatibility,Data-level compatibility.
Classification by type of processor used. The processor is the main component of any computer. In electronic computers this is a special unit, and in personal computers it is a special chip that performs all calculations. Even if computers belong to the same hardware platform, they may differ in the type of processor they use. The type of processor used largely (though not completely) characterizes the technical properties of the computer.
Classification by purpose is one of the earliest methods of classification. It has to do with how the computer is used. According to this principle, there are main computers (electronic computers), mini-computers, micro-computers, and personal computers, which, in turn, are divided into mass, business, portable, entertainment and workstations.
Mainframe computers - uh These are the most powerful computers. They are used to service very large organizations and even entire sectors of the national economy. Abroad, computers of this class are called mainframes ( mainframe). In Russia, the term mainframe computers was assigned to them. The maintenance staff for a large computer consists of up to many dozens of people. On the basis of such supercomputers, computer centers are created, which include several departments or groups.
The first mainframe computer ENIAC (Electronic Numerical Integrator and Computer) was created in 1946 (the 50th anniversary of the creation of the first computer was celebrated in 1996). This machine had a mass of more than 50 tons, speed of several hundred operations per second, RAM with a capacity of 20 numbers; occupied a huge hall with an area of about 100 sq.m.
The performance of large computers turned out to be insufficient for a number of tasks: weather forecasting, control of complex defense systems, modeling of environmental systems, etc. This was a prerequisite for the development and creation of supercomputers, the most powerful computing systems that are intensively developing at the present time.
Main directions effective application mainframes are the solution of scientific and technical problems, work in computing systems with batch information processing, working with large databases, managing computer networks and their resources. The last direction - the use of mainframes as large computer network servers - is often noted by experts as the most relevant.
Appearance in the 70s. small computers are due, on the one hand, to progress in the field of electronic element base, and on the other hand, the redundancy of mainframe computer resources for a number of applications. Small computers are most often used to control technological processes. They are more compact and much cheaper than large computers.
Further advances in the field of element base and architectural solutions led to the emergence of a supermini computer - a computer that belongs to the class of small computers in architecture, size and cost, but is comparable in performance to a large computer.
The invention of the microprocessor (MP) in 1969 led to the appearance in the 70s. Another class of computer is a microcomputer.
CPU
Rice. Structure of a modern computer center based on a mainframe computer
Classification of microcomputers:
universal (multi-user, single-user (personal))
· specialized (multi-user (servers), single-user (workstations))
It was the presence of MP that initially served as the defining feature of a microcomputer. Now microprocessors are used in all classes of computers without exception.
The functionality of a computer determines the most important technical and operational characteristics:
· performance, 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 operates;
· nomenclature, capacity and performance of all storage devices;
· nomenclature and technical and economic characteristics of external devices for storing, exchanging and input/output of information;
· types and capacity of communication devices and interfacing of computer nodes with each other (intra-machine interface);
· the ability of a computer to simultaneously work with several users and execute several programs simultaneously (multiprogramming);
· types and technical and operational characteristics of operating systems used in the machine;
Availability and functionality of software;
· ability to execute programs written for other types of computers (software compatibility with other types of computers);
· system and structure of machine commands;
· ability to connect to communication channels and to a computer network;
· operational reliability of the computer;
· coefficient of useful use of a computer over time, determined by the ratio of useful work time and maintenance time
Supercomputers include powerful multiprocessor computers with speeds of hundreds of millions - tens of billions of operations per second.
Despite the widespread use of personal computers, the importance of mainframe computers does not decrease. Due to the high cost of their maintenance, when operating large computers, it is customary to plan and take into account every minute. To save operating time on large computers, low-performance operations of input, output, and primary data preparation are performed using personal equipment. The prepared data is transferred to a mainframe computer to perform the most resource-intensive operations.
The central processor is the main unit of the computer, in which data processing and calculation of results directly take place. Typically, the central processor consists of several equipment racks and is located in a separate room, where increased requirements for temperature, humidity, protection from electromagnetic interference, dust and smoke are met.
Group system programming is engaged in the development, debugging and implementation of software necessary for the functioning of the computer system itself. Workers in this group are called system programmers. They must have a good knowledge of the technical structure of all computer components, since their programs are designed primarily to control physical devices. System programs ensure the interaction of higher-level programs with hardware, that is, the system programming group provides the hardware-software interface of the computer system.
The Application Programming group creates programs to perform specific operations on data. Workers in this group are called application programmers. Unlike system programmers, they do not need to know the technical structure of computer components, since their programs do not work with devices, but with programs prepared by system programmers. On the other hand, users, that is, specific performers of work, work with their programs. Therefore, we can say that the application programming group provides the user interface of the computer system.
The data preparation group prepares the data that will be processed by programs created by application programmers. In many cases, employees in this group enter data themselves using the keyboard, but they can also perform conversion of ready-made data from one type to another. For example, they can receive illustrations drawn by artists on paper and convert them into electronic form using special devices called scanners.
Group technical support deals with the maintenance of the entire computer system, repair and adjustment of devices, as well as connecting new devices necessary for the operation of other departments.
Group information support provides technical information all other divisions of the computer center according to their order. The same group creates and stores archives of previously developed programs and accumulated data. Such archives are called program libraries or data banks.
The data output department receives data from the central processor and converts it into a form convenient for the customer. Here information is printed on printing devices (printers) or displayed on display screens.
Large computers are characterized by the high cost of equipment and maintenance, so the operation of such supercomputers is organized in a continuous cycle. The most labor-intensive and time-consuming calculations are scheduled for night hours, when the number of maintenance personnel is minimal. During the daytime, the computer performs less labor-intensive but more numerous tasks. At the same time, to increase efficiency, the computer works simultaneously with several tasks and, accordingly, with several users. It switches from one task to another and does so so quickly and frequently that each user gets the impression that the computer is working only with him. This distribution of computing system resources is called the principle of time sharing.
Minicomputers – computers in this group differ from large computers in their reduced size and, accordingly, lower performance and cost. Such computers are used by large enterprises, scientific institutions, banks and some higher education institutions, combining educational activities with scientific.
In industrial enterprises, minicomputers control production processes, but can combine production management with other tasks. For example, they can help economists in monitoring the cost of production, standardizers in optimizing the time of technological operations, designers in automating the design of machine tools, and accounting departments in carrying out accounting. primary documents and preparing regular reports for tax authorities. To organize work with a mini-computer, a special computing center is also required, although not as numerous as for large computers.
Microcomputer– computers of this class are available to many enterprises. Organizations using microcomputers usually do not create computer centers. To maintain such a computer, they only need a small computing laboratory consisting of several people. The staff of a computing laboratory necessarily includes programmers, although they are not directly involved in program development. The necessary system programs are usually purchased along with the computer, and the development of the necessary application programs is ordered to larger computer centers or specialized organizations.
Computer laboratory programmers implement purchased or ordered software, fine-tune and configure it, and coordinate its operation with other computer programs and devices. Although programmers in this category do not develop system and application programs, they can make changes to them, create or change individual fragments. This requires high qualifications and universal knowledge. Programmers servicing microcomputers often combine the qualities of system and application programmers simultaneously.
Despite the relatively low performance compared to large computers, microcomputers are also used in large computer centers. There they are entrusted with auxiliary operations for which there is no point in using expensive supercomputers.
Personal computers (PCs)– this category of computers has undergone particularly rapid development over the past twenty years. From the name it is clear that such a computer is designed to serve one workstation. As a rule, one person works with a personal computer. Despite their small size and relatively low cost, modern personal computers have considerable productivity. Many modern personal computers are superior to the mainframe computers of the 70s, the minicomputers of the 80s, and the microcomputers of the first half of the 90s. Personal Computer ( Personal Computer, RS) is quite capable of meeting most of the needs of small businesses and individuals.
To meet the requirements of general accessibility and universality, a personal computer must have the following characteristics:
· low cost, within the reach of an individual buyer;
· autonomy of operation without special requirements to the conditions environment;
· flexibility of architecture, ensuring its adaptability to a variety of applications in the field of management, science, education, and in 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 operational reliability (more than 5000 hours between failures).
Abroad, the most common computer models currently are IBM PCs with Pentium and Pentium Pro microprocessors.
Domestic industry (CIS countries) produced DEC-compatible (interactive computing DVK-1 - DVK-4 based on Electronics MS-1201, Electronics 85, Electronics 32, etc.) and IBM PC-compatible (EC1840 - EC1842, EC1845, EC1849, ES1861, Iskra1030, Iskra 4816, Neuron I9.66, etc.) computers. Now the vast majority of domestic personal computers are assembled from imported components and are IBM PC-compatible.
Personal computers can be classified according to a number of criteria.
By generation, personal computers are divided as follows:
· 1st generation PCs - use 8-bit microprocessors;
· 2nd generation PCs - use 16-bit microprocessors;
· 3rd generation PCs - use 32-bit microprocessors;
· 4th generation PCs - use 64-bit microprocessors.
· 5th generation PCs – use 128-bit microprocessors.
Personal computers became especially popular after 1995 due to the rapid development of the Internet. A personal computer is quite enough to use the World Wide Web as a source of scientific, reference, educational, cultural and entertainment information. Personal computers are also a convenient means of automating the educational process in any discipline, a means of organizing distance (correspondence) learning, and a means of organizing leisure time. They make a great contribution not only to production, but also to social relations. They are often used to organize home-based work activities, which is especially important in conditions of limited employment.
Until recently, personal computer models were conventionally considered in two categories: household PCs and professional PCs. Consumer models generally had lower performance, but they took special care to handle color graphics and sound that professional models did not need. Due to the sharp reduction in the cost of computer technology achieved in recent years, the boundaries between professional and household models in to a large extent have worn off, and today high-performance professional models are often used as household ones, and professional models, in turn, are equipped with devices for reproducing multimedia information, which was previously typical for household devices. The term multimedia means a combination of several types of data in one document (text, graphic, music and video data) or a set of devices for reproducing this complex of data.
Since 1999, an international certification standard, the PC99 specification, has come into force in the field of personal computers. It regulates the principles of classification of personal computers and stipulates the minimum and recommended requirements for each category. The new standard establishes the following categories of personal computers:
Consumer PC (mass PC);
Office PC (business PC);
Mobile PC (portable PC);
Workstation PC (workstation);
Entertaimemt PC (entertainment PC).
According to the PC99 specification, most personal computers currently on the market fall into the mainstream PC category. For business PCs, the requirements for graphics reproduction tools are minimized, and there are no requirements for working with audio data at all. For laptop PCs, it is mandatory to have tools for creating remote access connections, that is, computer communication tools. In the workstation category, the requirements for data storage devices have increased, and in the entertainment PC category, for graphics and sound reproduction tools.
Thus, in conclusion, we can say the following. On currently There are many systems and methods, principles and bases for classifying computers. This paper presents the most common classifications of computers.
Thus, computers are classified by purpose (mainframe computers, mini-computers, micro-computers, personal computers), by level of specialization (universal and specialized), by standard sizes (desktop, portable, pocket, mobile), by compatibility, by type of used processor, etc. There are no clear boundaries between classes of computers. As structures and production technologies improve, new classes of computers appear, and the boundaries of existing classes change significantly.
The earliest classification method is the classification of computers by purpose.
The most common type of computer is personal computers, divided into mass, business, portable, entertainment and workstations.
The division of computer technology into generations is a very conditional, loose classification of computing systems according to the degree of development of hardware and software, as well as methods of communicating with a computer.
The idea of dividing cars into generations was brought to life by the fact that during the short history of its development computer technology has made a great evolution both in terms of the element base (lamps, transistors, microcircuits, etc.), and in the sense of changing its structure, the emergence of new opportunities, expanding the scope of applications and the nature of use.
According to operating conditions, computers are divided into two types: office (universal); special.
Office ones are designed to solve a wide class of problems under normal operating conditions.
Special computers are used to solve a narrower class of problems or even one problem that requires multiple solutions, and operate in special conditions operation. The machine resources of dedicated computers are often limited. However, their narrow orientation makes it possible to implement a given class of tasks most effectively.
2. Encryptor, Decryptor
Encryptor, or coder called a combinational logic device for converting numbers from decimal system numbering to binary. The encoder inputs are sequentially assigned the values of decimal numbers, so the application of an active logical signal to one of the inputs is perceived by the encoder as the application of the corresponding decimal number. This signal is converted at the output of the encoder into binary code. According to what has been said, if the encoder has n outputs, the number of its inputs should be no more than 2 n. Encoder having 2 n entrances and n outputs is called complete. If the number of encoder inputs is less 2 n, it is called incomplete.
Let's consider the operation of the encoder using the example of a converter of decimal numbers from 0 to 9 into binary decimal code. The truth table corresponding to this case has the form
Since the number of inputs of this device is less 2 n= 16, we have an incomplete encoder. Using the table for Q 3 , Q 2 , Q 1 and Q 0 , you can write the following expressions:
The resulting FAL system characterizes the operation of the encoder. The logical diagram of the device corresponding to the system is given in the picture below.
Related information.
What is a computer?
Computer (English computer - computer) - a programmable electronic computing device for data processing, transmission and storage of information. That is, a computer is a complex of software-controlled electronic devices.
The term " computer" (or " Personal Computer") is synonymous with the abbreviation " computer"(electronic computer) or "PC" (personal computer). After the advent of personal computers (from the English personal computer, PC), the term computer was subsequently practically driven out of use and replaced by the borrowed term “computer”, “PC” or “PC”. The fact is that if the designations “PC” and “PC” characterize a computer as a “single-user general purpose computer,” then the term “PC” means precisely an IBM PC-compatible computer.
With the help of calculations, a computer is able to process information according to a predetermined algorithm. In addition, a computer, using software, is capable of receiving, storing and searching for information, and outputting information to various types of output devices. Computers got their name from their main function - performing calculations. Currently, in addition to direct computing functions, computers are used for processing and managing information, as well as games.
The computer design scheme was proposed by the famous mathematician John von Neumann in 1946; its operating principles have largely been preserved in modern computers.
First of all, a computer, according to von Neumann's principles, must have the following devices:
* Arithmetic Logic Unit (ALU) that performs arithmetic and logical operations;
* control device (CU), which organizes the process of program execution;
* storage device (memory), or memory for storing programs and data;
* external devices for input/output of information.
The computer's memory must consist of a certain number of numbered cells, each of which can contain either processed data or program instructions. All memory cells must be equally easily accessible to other computer devices.
In addition to computer architecture, Neumann proposed fundamental principles logical device COMPUTER.
John von Neumann's principles:
1. The principle of program control (a program consists of a set of commands that are executed by the processor one after another in a certain sequence);
2. The principle of memory homogeneity (programs and data are stored in the same memory);
3. The principle of addressing (the main memory consists of numbered cells, and any cell is available to the processor at any time).
Computers built on these principles are referred to as “von Neumann” computers. Today these are the vast majority of computers, including IBM PC compatible. But there are also computer systems with a different architecture - for example, systems for parallel computing.
Typically, a computer is designed based on the open architecture principle:
* Description of the operating principle of a PC and its configuration, which allows you to assemble a PC from individual components and parts;
* The presence of internal expansion slots in the PC into which the user can insert various devices that meet a given standard.
In the majority modern computers the problem is first described in a form they understand, with the entire necessary information is represented in binary form (in the form of ones and zeros), after which the actions to process it are reduced to the application of simple algebra of logic. Since virtually all mathematics can be reduced to performing Boolean operations, a sufficiently fast electronic computer can be used to solve most mathematical problems (and also most information processing problems that can be easily reduced to mathematical ones).
The result of the completed task can be presented to the user using various information output devices, such as lamp indicators, monitors, printers, projectors, etc.
It was discovered that computers still cannot solve any math problem. Problems that cannot be solved by computers were first described by the English mathematician Alan Turing.
Applications of computers
The first computers were created directly for computing (as reflected in the names “computer” and “computer”). It's no coincidence that I'm the first high level language programming was Fortran, intended solely for performing mathematical calculations.
The second major application was databases. First of all, governments and banks needed them. Databases require more complex computers with developed input-output and information storage systems. For these purposes, the Cobol language was developed. Later, DBMS (database management systems) appeared with their own programming languages.
The third application was to control all kinds of devices. Here, development proceeded from highly specialized devices (often analogue) to the gradual introduction of standard computer systems on which control programs were run. In addition, more and more equipment is beginning to include a control computer.
Finally, computers have developed so much that the computer has become the main information tool both in the office and at home. That is, now almost any work with information is carried out through a computer - be it typing or watching movies. This applies to both storing information and sending it over communication channels.
Modern supercomputers are used to simulate complex physical and biological processes - for example, nuclear reactions or climate change. Some projects are carried out using distributed computing, when a large number is relatively weak computers simultaneously working on in small parts common task, thus forming a very powerful computer.
The most complex and underdeveloped application of computers is artificial intelligence - the use of computers to solve problems where there is no clearly defined, more or less simple algorithm. Examples of such tasks are games, machine translation of text, expert systems.
GENERAL INFORMATION ABOUT COMPUTERS AND COMPUTING SYSTEMS
| Parameter name | Meaning |
| Article topic: | GENERAL INFORMATION ABOUT COMPUTERS AND COMPUTING SYSTEMS |
| Rubric (thematic category) | Computers |
Electronic computers (computers), computer systems (CS) and computer networks are used to process information.
A computer is an electronic device for storing and automatically processing information.
Basic function blocks COMPUTER:
1) input device (IDU);
2) storage device (memory);
3) arithmetic-logical unit (ALU);
4) control device (CU);
5) output device (UVV).
To solve the problem, a program, ᴛ.ᴇ. a sequence of commands written in a language understandable by the computer. Programs and data recorded on a computer medium (for example, a magnetic disk) are entered into a computer via a computer and transferred to the memory (computer memory).
The largest number of commands and data that can be simultaneously stored in the memory is determined by memory capacity. The time required to search, write and read information determines computer speed.
The memory necessarily includes operational (RAM) and read-only (ROM) storage devices that make up internal memory.
External memory The computer is designed to store intermediate results that do not fit into RAM, input and output data. External memory is practically unlimited, but its speed is significantly less than RAM.
To organize interaction between computer devices during program execution, the control unit is used. At the direction of the CU, the next command is entered and decrypted, an instruction is transmitted to the RAM as to what data to transfer to the ALU and what operation to perform. Intermediate results are sent to RAM for storage. The ALU performs arithmetic and logical operations on the data. The results of the work are transferred to UVV. Since the same devices can be used for both input and output, they are called input/output devices (I/O).
The control unit, arithmetic logic unit and high-speed register memory (ultra random access memory) make up CPU(CPU). In a personal computer, its functions are performed by a microprocessor.
Computing systems– a set of computer equipment, which includes at least two base processors or computers (universal or specialized) and a developed system of peripheral devices.
Peripherals- ϶ᴛᴏ external storage devices and input/output devices.
PERSONAL COMPUTER(PC) or PC – general-purpose single-user computer(y universal– since it can be used to solve problems different types, A single-user– since one user can work at a time). From the name it is clear that such a computer is designed to serve one workstation.
The configuration (hardware composition) of the PC can be flexibly changed if it is extremely important. With all the variety of computers in any computer, the following components can be distinguished:
· system unit;
· display for visual display of information;
· keyboard for entering symbolic information;
· mouse (or other pointing device);
· peripherals.
The first four components make up basic configuration, which can be expanded with additional external devices.
The system unit houses the main components of the PC (called internal), the most important of which is the motherboard (system) board. It contains the basic set of PC electronics (CPU, electronic devices (chipsets) and others).
Everything is connected to the system unit external devices: monitor, keyboard, mouse, printer, modem, scanner, speakers, etc.
The following devices are located in the SYSTEM UNIT.
1. Motherboard, on which the following devices are located.
· Microprocessor (MP). This is the main PC chip that performs most logical and mathematical operations. Structurally, the processor consists of an array of crystalline cells in which data can be stored and changed. The internal cells of the processor are called registers. The processor is connected to the rest of the computer devices, and primarily to the RAM, by several groups of conductors called tires. There are three main buses: data bus, address bus and command bus.
Address bus for processors Intel Pentium 32-bit, that is, it consists of 32 parallel lines, on which one or zero is set based on whether there is voltage on the line or not. The combination of 32 zeros and ones forms a 32-bit address pointing to one of the RAM cells. The processor is connected to it to copy data from the cell into one of its registers.
By data bus Data is copied from RAM to processor registers and back. In computers with an Intel Pentium processor, the data bus is 64-bit, that is, it consists of 64 lines, along which 8 bytes are received at a time for processing.
Command bus is designed to transfer commands to the processor from those areas of RAM where programs (and not data arrays) are stored, since in order for the processor to process data, it needs commands. Commands are represented as bytes. The Intel Pentium processor has a 32-bit instruction bus.
Modern processors perform hundreds of millions of operations per second, allowing the PC to solve very complex tasks for short periods of time.
The processor is responsible for the performance characteristics of the PC. Microprocessors differ in a number of important characteristics: processor bit capacity, information processing clock frequency.
Processor size shows how many bits of data it can receive and process in its registers in one clock cycle. The first processors were 16-bit, starting with the 80386 - 32-bit.
Clock frequency of information processing. All processes associated with calculations, processing and transfer of data between PC modules must be mutually consistent in time, ᴛ.ᴇ. synchronized. Synchronization of the CPU and all PC nodes is carried out using a clock generator, which generates periodic sequences of clock pulses. Tact called the time interval between the beginning of the supply of two successive pulses of electric current that are generated by the clock generator.
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A sequence of clock pulses is sent to the CPU, to the memory system, and to all other computer devices to synchronize the operation of the CPU and all computer nodes. Clock frequency- ϶ᴛᴏ number of ticks per second and is measured in megahertz(1 MHz = 1 million cycles per second), affects the operating speed and performance of the MP.
Processor speed- ϶ᴛᴏ the number of operations it performs per second. Produces hundreds various operations at speeds reaching hundreds of millions of operations per second.
PCs use microprocessors developed by Intel, AMD and others. Today, INTEL 80486 microprocessors are being replaced by more powerful Pentium microprocessors (Pentium 3, Pentium 4 with frequencies of 500 megahertz and higher.
· Video adapter (video card)- a device that controls the display of text information and graphic images. The video adapter organizes the interface between the PC and the display. Physically, the video adapter is made in the form of a separate board, which is inserted into one of the slots on the motherboard.
Today, SVGA video adapters are used, providing optional reproduction of up to 16.7 million colors with the ability to select screen resolution from a number of values (for example, 1024 * 768 pixels for 17-inch monitors).
· RAM- ϶ᴛᴏ an array of crystalline cells capable of storing data. Used to record and read information. If the power is turned off, the information recorded in the memory will be lost. It is characterized by performance comparable to that of a microprocessor.
The main characteristics of RAM are capacity and access time. Capacity Modern RAM is several GB. Access time shows how much time is critical for accessing memory cells, measured in billionths of a second (nanoseconds, ns). It is important to note that for modern memory modules it is 7-10 ns.
· ROM- designed to store short programs necessary for the operation of a PC.
When the computer is turned on, there is nothing in its RAM - neither data nor programs, since RAM cannot store anything without recharging the cells for more than hundredths of a second, but the processor needs commands, incl. and at the first moment of switching on. For this reason, immediately after switching on, the start address is set on the processor’s address bus (this happens in hardware, without the participation of programs). The processor addresses the set address for its first command and then begins to work according to the programs. This address points to the ROM. The ROM chip is capable of storing information even when the computer is turned off. A set of programs located in ROM forms basic system I/O. The main purpose of the programs in this package is to check the composition and performance of the computer system and ensure the interaction of all its components.
· Cache memory– it is also called “super RAM”.
Data exchange within the processor occurs several times faster than exchange with other devices, for example, with RAM. In order to reduce the number of accesses to RAM, a buffer area is created inside the processor - the so-called cache memory. When the processor needs data, it first accesses the cache memory, and only if the necessary data is not there, does it access the RAM. Receiving a block of data from RAM, the processor simultaneously enters it into cache memory. Cache memory is functionally designed to match the speed of relatively slow devices with a relatively fast CPU. Compared to OP, cache memory has a small capacity. In addition to the cache memory built into the CPU, it must be removed from the CPU. On-chip cache is the fastest, with L1 cache typically 32 KB in capacity.
· Chipset- ϶ᴛᴏ chipset designed to support in PC functionality provided by the processor, OP, cache memory, disk and video memory and other components and associations components PC. Its chips generate most of the signals for system and peripheral components and convert signals between buses.
· Controllers are designed to control access from the system to any of the devices, as well as to perform operations information exchange. Each external device has its own controller.
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After receiving commands from the CPU, the controller performs maintenance operations external device. Controllers built into the motherboard are widely used (controllers for keyboards, HDDs, HDDs, ports, video systems).
2. Disk drive (storage) for flexible magnetic disks (FMD). For quick transfer small volumes data is used floppy disks(floppy disks) that are inserted into a special drive - drive. Correct direction for feeding the floppy disk into the drive opening located on the front panel system unit, marked with an arrow on its plastic casing.
The drive is used to write, read and store information on floppy disks (floppy disks). Today, floppy disks with a diameter of 3.5" with a capacity of 1440 bytes are used ( 1.4 MB) and HD marking.
Floppy disks– unreliable storage media. Dust, dirt, moisture, temperature changes and external electromagnetic fields often cause partial or complete loss of information. For this reason, using them as the main means of storing data is unacceptable. They are used to transport data or as an additional (backup) storage medium.
3. Hard magnetic disk drive (HDD) or Winchester. Designed for long-term storage (can store information for decades).
A hard drive is not actually a single drive, but a group of coaxial disks that are magnetically coated and spin at high speeds. However, the hard drive has not two surfaces, but 2n surfaces, where n is the number of individual disks in the group.
Capacity hard drives today - from several GB to several tens of GB.
4. CD-ROM drive . Digital recording on a CD is very different from recording on magnetic disks high density, and a standard CD can store approximately 650 MB of data. Οʜᴎ are different high reliability information storage, durability (their predicted service life with high-quality performance is 30-50 years). The disc diameter should be either 5.25" or 3.5".
The operating principle of this device is reading numerical data using a laser beam reflected from the surface of the disk. Large amounts of data are typical for multimedia information (graphics, music, video), and therefore CD-ROM drives are classified as hardware multimedia.
5. Tires. All electronic elements of a PC exchange information with each other and are interconnected using buses - a set of lines and microcircuits that transmit electrical signals between various components PC. The totality of all tires is usually called system highway. The buses transmit signals: address, control and data; in this regard, they are distinguished: data bus (for data transmission), address bus (for transmitting address information codes to RAM) and control bus (includes lines for transmitting control signals).
Tires are characterized bit depth, ᴛ.ᴇ. the number of information bits simultaneously transmitted along the bus lines. In PC architecture, the most common buses are 8-, 16-, and 32-bit. The amount of information transmitted over a channel in 1 time is usually called bus throughput.
6. Communication ports (I/O ports). They serve to connect the PC with devices that are structurally designed separately from the system unit. Specialized ports are used for exchange with internal devices. Ports general purpose used to connect external devices: parallel LPT1-LPT* and serial COM1-COM*.
MONITOR ( display) – a device for visual presentation of data. This is the main output device. Serves to output text and graphic information data entered from the keyboard or output from the PC, system messages and user information.
Screen size measured between opposite corners of the picture tube screen diagonally in inches. Today, 19" and 21" monitors are widely used.
Permission screen is one of important parameters monitor. The higher it is, the more information can be displayed on the screen, but smaller size each individual point, and therefore the visible size of the image elements is smaller.
The display and video card (graphics card) make up video system PC. Video systems use analog and digital technology to produce images on the screen. IN analog technologies Cathode ray tube displays are used, while digital ones use liquid crystal flat-screen displays.
The KEYBOARD is used to enter alphanumeric data and control commands into the PC. Basic keyboard functions do not need driver support ( special programs). The necessary software to get started with your computer is already available in the ROM chip in the BIOS.
The MOUSE allows you to point at screen elements using a pointer and, after clicking buttons, perform certain operations.
The PRINTER outputs text and graphic information (black and white or color) onto paper or film.
The MODEM is used to connect a PC to a telephone line.
SCANNER – a device for entering text or graphic information (black and white and color) into a PC for further processing.
The SOUND SYSTEM consists of a sound card and speakers(may be built into the display). The speakers have their own amplifiers and sound level controls.
The most promising is the use of a PC as part of a computer network (CN). In this case, several PCs, and possibly computers of other classes, are connected together through communication channels and interface equipment with them for the exchange of information.
Computer network It is customary to call a set of PCs interconnected through data transmission channels, which provide users with the exchange of information and collective use of network resources.
Network hardware:
- workstations(workstation - a PC connected to the network on which the network user performs his work);
- server(a computer connected to a network and providing certain general-purpose services to network users);
- network cards (adapters);
- modems;
- cables or other transmission media.
By degree of territorial distribution networks are classified into: global, regional and local networks.
Global networks unite users located all over the world, often using satellite communication channels (the distance between network nodes is 10-15 thousand km). They are called WAN.
Regional– unite users of the city and region. Telephone lines are used as communication channels (the distance between network nodes is 10-1000 km). They are called MAN.
Local networks connect subscribers of one or more nearby buildings. PCs are connected by a single high-speed data transmission channel. The distances between computers are small – up to 10 km. Channels in local networks are the property of organizations, and this simplifies their operation.
Networks consisting of software-compatible computers are called homogeneous. If a software-incompatible computer is included in the network, then the network is usually called heterogeneous.
Using local networks provides the following advantages:
· simultaneous work of several users with data of general use (DBMS, IT);
· data protection at the directory and file level;
· the ability to permanently store software needed by many users in one copy;
· exchange of information between all PCs on the network, which ensures dialogue between network users, as well as the ability to organize e-mail;
· simultaneous printing by all network users on network-wide printers;
· increasing the efficiency of information processing systems by reducing costs, etc.
A global network capable of uniting many networks and allowing entry into the world community is Internet.
Today there is no single owner of the Internet. Each company is the owner of its part of the network. It also has the necessary software and hardware, with the help of which data is exchanged both within its network and within the Internet. This company also ensures the transit of information through its network. In case of failures in some part of the network, all information will “flow around” this area.
Ways to connect to the Internet
· Connecting an individual PC. To do this, you need to have a modem, a telephone line and an organization that has a gateway (entrance) to the Internet. Such organizations are suppliers network services- are called providers. Login to the Internet is carried out through the provider's PC. This PC is usually called host. The user works on the network without an address. It is contained by the host PC. All information that the user pumps goes through the host.
· Direct connection. Direct connection to the Internet is carried out via dedicated leased communication lines using additional software.
An analysis of the practice of using aircraft has shown that there are quite a lot of ways of information leakage: illegal connection to equipment and communication lines, interception of electronic radiation, interception of acoustic radiation and restoration of printer text, theft of information media, reading data from other users’ arrays, reading residual information in the system memory after executing an authorized request, masquerading as a registered user, introducing viruses, etc.
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In this regard, information protection measures are of particular importance:
Organizational (restriction of access to the premises where information is processed; storage of computer media in safes; use of security codes when transmitting information, etc.);
Technical and software.
GENERAL INFORMATION ABOUT COMPUTERS AND COMPUTER SYSTEMS - concept and types. Classification and features of the category "GENERAL INFORMATION ABOUT COMPUTERS AND COMPUTING SYSTEMS" 2017, 2018.
A computer (from the English computer - calculator) is a programmable electronic computing device designed for storing and transmitting information, as well as processing data. That is, a computer is a complex of software-controlled electronic devices.
The term " personal computer r" is a synonym for the abbreviation " computer"(electronic computer). When personal computers appeared, the term computer soon fell out of use, being replaced by the term "computer", " PC" or " PC».
A computer can use calculations to process information according to a specific algorithm. In addition, software allows the computer to store, receive, and retrieve information, as well as output it to various input devices. The name of computers comes from their main function - computing, but today, in addition to computing, computers are used for processing information, as well as for games.
The computer circuit was proposed in 1949 by mathematician John von Neumann, and since then the principle of the device has remained almost unchanged.
According to von Neumann's principles, a computer should consist of the following devices:
an arithmetic logic unit that performs logical and arithmetic operations;
a storage device for storing data;
a control device that organizes the process of program execution;
information input/output devices.
Computer memory must consist of a certain number of numbered cells, each of which contains program instructions or processed data. Cells are available to all computer devices.
Most computers are designed using an open architecture principle:
a description of the configuration and operating principle of a PC, allowing you to assemble a computer from individual parts and assemblies;
the presence in the computer of expansion slots into which you can insert devices that comply with a given standard.
In most computers today, a problem is first described in an understandable way by providing information in binary form, and then it is processed using logic and simple algebra. Since almost all mathematics can be reduced to Boolean operations, most mathematical problems can be solved using a fast electronic computer. The result of calculations is presented to the user by information input devices - printers, lamp indicators, monitors, projectors.
However, it was found that computers cannot solve any mathematical problem. English mathematician Alan Turing described the first problems that could not be solved by a computer.
Applications of computers
The first computers were created only for calculations (as the name suggests), and the first high-level programming language was Fortran, which was intended only for performing mathematical calculations.
Then computers found another use - databases. First of all, banks and governments needed them. Databases required more complex computers with advanced information storage and input-output systems. The Cobol language was developed to meet these requirements. After some time, database management systems (DBMS) appeared, which had their own programming languages.
Another use of computers is to control various devices. The field has evolved gradually, from highly specialized devices (often analog) to standard computer systems that run control programs. Besides this, more and more modern technology includes a control computer.
Today, the development of the computer has reached such a level that it is the main information tool both at home and in the office. Thus, almost all work with information is carried out through a computer - from typing texts to watching films. This also applies to storing and forwarding information.
Scientists use modern supercomputers to simulate complex biological and physical processes such as climate change or nuclear reactions. Some projects are carried out using distributed computing, in which a large number of not very powerful computers simultaneously solve different parts of the same problem, thereby forming one powerful computer.
The most complex and not yet highly developed area of using computers is artificial intelligence - the use of computers in solving problems that do not have a clear, relatively simple algorithm. Examples of such tasks are games, expert systems, and machine translation of text.
