4. Trends in the development of computer technology
According to experts, in the first decade of the 21st century. The importance of software will increase, and the problems of its compatibility and security will increase.
Among operating systems, Linux and Windows systems will receive further development. From the end user's point of view, in the coming years there should be major changes in the way he communicates with his computer. Firstly, graphical data input will be used more widely, including in the automatic handwriting recognition mode. Secondly, voice input will be used - first to control commands, and then automatic speech digitization will be mastered. To solve the above problems, corresponding external devices will be developed.
Work in the field of intelligent processing of unstructured data, primarily texts, and then graphics, sound, and video, will be of great importance in the future.
One of the most promising directions in the development of computer technology is the implementation of the concept of network computing, which uses the idea of using free computer resources for calculations. This concept is called Grid and includes five key points:
Application of open standards;
Integration of heterogeneous systems;
Data sharing;
Dynamic resource allocation;
Consolidation of computer networks of many enterprises and organizations.
The development of computers will follow the path of creating optoelectronic computers with massive parallelism and a neural structure, which are a distributed network of a large number (tens of thousands) of simple microprocessors modeling the architecture of neural biological systems.
Portable personal computers with wireless connections to the global Internet will receive further development.
It should be noted that the development of computer technology entirely depends on the trends in the development of the world economic system.
Lecture No. 6 History of the development of computer technology
Lecture No. 3 Generations and classification of computers
1.Generations of computing technology
There are five generations of computers.
First generation(1945-1954) is characterized by the appearance of technology using vacuum tubes. This is the era of the emergence of computer technology. Most of the first generation machines were experimental devices and were created to test certain theoretical principles. The weight and size of these computers were such that they often required separate buildings.
The founders of computer science are rightfully considered to be Claude Shannon, the creator of information theory, Alan Turing, a mathematician who developed the theory of programs and algorithms, and John von Neumann, the author of the design of computing devices, which to this day underlies most computers. In those same years, another new science related to computer science arose - cybernetics - the science of management as one of the main information processes. The founder of cybernetics is the American mathematician Norbert Wiener.
In the second generation(1955-1964), transistors were used instead of vacuum tubes, and magnetic cores and drums began to be used as memory devices - prototypes of modern hard drives. All this made it possible to reduce the size and cost of computers, which then began to be produced for sale for the first time.
But the main achievements of this era relate to the field of programs. In the second generation, what is now called an operating system first appeared. At the same time, the first high-level languages were developed - Fortran, Algol, Cobol. These two important improvements made writing computer programs much easier and faster.
At the same time, the scope of computer applications expanded. Now it was no longer just scientists who could count on access to computer technology, as computers were used in planning and management, and some large firms even began to computerize their accounting, anticipating this process by twenty years.
IN third generation(1965-1974) for the first time integrated circuits began to be used - entire devices and assemblies of tens and hundreds of transistors, made on a single semiconductor crystal (microcircuit). At the same time, semiconductor memory appeared, which is still used in personal computers as operational memory.
In those years, computer production assumed an industrial scale. IBM was the first to sell a series of computers that were fully compatible with each other, from the smallest, the size of a small closet (they had never made anything smaller then), to the most powerful and expensive models. The most widespread in those years was the System/360 family from IBM, on the basis of which the ES series of computers was developed in the USSR. Back in the early 1960s. The first minicomputers appeared - low-power computers affordable for small firms or laboratories. Minicomputers were the first step towards personal computers, prototypes of which were not released until the mid-1970s.
Meanwhile, the number of elements and connections that fit into one chip was constantly growing, and in the 1970s. integrated circuits already contained thousands of transistors.
In 1971, Intel released the first microprocessor, which was intended for desktop calculators that had just appeared. This invention created a real revolution in the next decade. The microprocessor is the main component of a modern personal computer.
At the turn of the 1960s and 70s. (1969) the first global computer network ARPA appeared, the prototype of the modern Internet. In the same 1969, the Unix operating system and the C programming language appeared simultaneously, which had a huge impact on the software world and still retain their dominant position.
Fourth generation(1975 -1985) is characterized by a small number of fundamental innovations in computer science. Progress went mainly along the path of developing what had already been invented and invented, primarily through increasing power and miniaturization of the element base and the computers themselves.
The most important innovation of the fourth generation is its appearance in the early 1980s. personal computers. Thanks to them, computing technology becomes truly widespread and accessible to everyone. Despite the fact that personal computers and minicomputers still lag behind solid machines in terms of computing power, most of the innovations, such as graphical user interfaces, new peripheral devices, and global networks, are associated with the emergence and development of this particular technology.
Large computers and supercomputers, of course, continue to develop. But now they no longer dominate the computer world as they once did.
Some characteristics of four generations of computer technology are given in
|
Characteristic |
Position |
|||
|
first |
second |
third |
fourth |
|
|
Main element |
Electric lamp |
Transistor |
Integrated circuit |
Large integrated circuit |
|
Number of computers in the world, pcs. |
Tens of thousands |
Millions |
||
|
Computer size |
Significantly smaller |
Tens of thousands |
Micro computer |
|
|
Performance (conditional) of operations/ With |
Several units |
Several dozen units |
Several thousand units |
Several tens of thousands of units |
|
Storage medium |
Punched card, punched tape |
Magnetic tape |
floppy disk |
|
Fifth generation(1986 to the present) is largely determined by the results of the work of the Japanese Committee for Scientific Research in the Field of Computers, published in 1981. According to this project, computers and computing systems of the fifth generation, in addition to high performance and reliability at a lower cost, using the latest technologies, must satisfy the following qualitatively new functional requirements:
ensure ease of use of computers by implementing voice input/output systems, as well as interactive information processing using natural languages;
provide the possibility of learning, associative constructions and logical conclusions;
simplify the process of creating software by automating the synthesis of programs according to the specifications of the original requirements in natural languages;
improve the basic characteristics and performance qualities of computer technology to satisfy various social problems, improve the cost-benefit ratio, speed, lightness, and compactness of computers;
provide a variety of computing equipment, high adaptability to applications and reliability in operation.
Currently, intensive work is underway to create optoelectronic computers with massive parallelism and a neural structure, which are a distributed network of a large number (tens of thousands) of simple microprocessors that model the architecture of neural biological systems.
2. Classification of electronic computers
Computers can be classified according to a number of characteristics:
According to the principle of action.
According to the purpose of the computer.
In terms of size and functionality.
According to the operating principle of a computer :
AVMs are continuous analog 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);
Digital computers are discrete digital computers that work with information presented in discrete (digital) form;
GVMs are hybrid computers of combined action that work with information presented in both digital and analog forms. GVMs combine the advantages of AVM and TsVM. It is advisable to use them to solve problems of managing complex high-speed technical systems.
According to the purpose of the computer :
mainframe computers designed to solve a wide variety of engineering and technical problems: economic, mathematical, information and others, characterized by the complexity of algorithms and a large volume of processed data;
problem-oriented computers serve to solve a narrower range of problems associated, as a rule, with the control of technological processes;
specialized computers are used to solve a narrow range of problems or implement a strictly defined group of functions.
In size and functionality :
ultra-small (microcomputers) owe their appearance to the invention of the microprocessor, the presence of which initially served as a defining feature of microcomputers, although now microprocessors are used in all classes of computers without exception;
small (mini-computer) are most often used to control technological processes;
mainframe computers most often called mainframes. The main areas of effective use of mainframes are solving scientific and technical problems, working in computer systems with batch information processing, working with large databases, managing computer networks and their resources;
extra-large (supercomputer)– powerful multiprocessor computers with a speed of tens of billions of operations per second and a RAM capacity of tens of GB.
3. Principles of the structure and operation of John von Neumann's computers
Most modern computers operate on the basis of principles formulated in 1945 by an American scientist of Hungarian origin, John von Neumann.
1. Binary coding principle. According to this, all information entering the computer is encoded using binary symbols (signals).
2. Program control principle. A computer program consists of a set of commands that are executed automatically by the processor one after another in a certain sequence.
3. The principle of memory homogeneity. Programs and data are stored in the same memory, so the computer does not distinguish between what is stored in a given memory cell - a number, text or command. You can perform the same actions on commands as on data.
4. Targeting principle. Structurally, main memory consists of numbered cells, any of which is accessible to the processor at any time.
According to von Neumann, a computer consists of the following main blocks:
1) information input/output device;
2) computer memory;
3) processor, including a control unit (CU) and an arithmetic-logical unit (ALU).
During computer operation, information enters memory through input devices. The processor retrieves the processed information from memory, works with it and places the processing results into it. The results obtained are communicated to a person through output devices.
Computer memory consists of two types of memory: internal ( operational) and external ( long-term).
RAM is an electronic device that stores information while it is powered by electricity. External memory is a variety of magnetic media (tapes, disks), optical disks.
Over the past decades, the process of improving computers has proceeded within the framework of the given generalized structure.
4.Classification of personal computers
As mentioned above, a personal computer (PC) is a universal single-user microcomputer.
A personal computer is primarily a publicly accessible computer and has a certain versatility.
To meet the user's needs, the PC must have the following properties:
have a relatively low cost and be accessible to individual buyers;
ensure autonomous operation without special requirements for environmental conditions;
provide flexibility of architecture, making it possible to rebuild it for a variety of applications in the field of management, science, education, and in everyday life;
the operating system and software must be simple enough so that a user can work with a PC without professional special training;
have high operational reliability (more than 5000 hours between failures).
In accordance with the international standard specification RS99, PCs are divided into the following categories according to their intended purpose:
mass PC (Consumer);
business PC (Office PC);
portable PC (Mobile PC);
workstation (Workstation PC);
entertainment PC (Entertainment PC).
Most PCs currently available on the market are mainstream. 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, i.e. computer communication means. In the workstation category, the requirements for data storage devices have increased, and in the entertainment PC category, for audio and video playback.
PCs are divided by generation:
on 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.
PCs can also be divided into two large groups: stationary and portable. Laptop computers include laptops, electronic notebooks, secretaries and notepads.
Electronic computer is a set of hardware and software designed to automate the preparation and solution of user problems. 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 programs for managing technical means, information interaction between levels, and organizing the computing process. Application programmers develop higher-level software packages that provide user interaction with computers and the necessary services when solving their problems.
The structure of a computer is determined by the following group of 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 of functional modules of the 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 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. An electronic computer, a computer, is a set of technical means designed for automatic processing of 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 (DCM) 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.
The most widely used digital computers with electrical representation of discrete information are 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: Computers based on discrete semiconductor devices (transistors);
3rd generation, 70s: Computers based on semiconductor integrated circuits with a low and medium degree of integration (hundreds, thousands of transistors in one case);
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 a distributed network of a large number (tens of thousands) of simple microprocessors modeling 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 using 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 productivity and reliability of their operation. Specialized computers include, for example, programmable microprocessors for special purposes; 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 are 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 the central computer of your organization from any geographical location. This is how messages are exchanged, orders and instructions are transmitted, commercial data, reports and reports are received. Laptop computers are not very convenient for use in the workplace, 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 hard-wired software, which makes direct operation easier, but reduces the 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 to work mobile with the Internet, and in the near future, the ability to receive television broadcasts. Additionally, the MVU 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 a certain type of work (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 be used as a full-fledged workstation, and 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, such as washing machines, microwave ovens and VCRs, are also specialized. On-board computers control orientation and navigation aids, monitor the status 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 an object’s fuel consumption depending on specific driving 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, ordinary general-purpose computers can handle the tasks of specialized computer systems, 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 level, software compatibility, compatibility at the data level.
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 amounts 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.
The main areas of effective use of mainframes are solving scientific and technical problems, working in computer 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 among the most relevant.
Appearance in the 70s. small computers is due, on the one hand, to progress in the field of electronic components, and on the other, to the redundancy of large 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 the 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 speed 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.
The system programming group 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.
The technical support group is responsible for maintaining the entire computer system, repairing and setting up devices, as well as connecting new devices necessary for the operation of other departments.
The information support group provides technical information to all other divisions of the computer center upon their request. 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 educational institutions that combine educational activities with scientific ones.
In industrial enterprises, minicomputers control production processes, but can combine production management with other tasks. For example, they can help economists in monitoring product costs, standardization specialists in optimizing the time of technological operations, designers in automating the design of machine tools, accounting departments in recording 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 at the same time.
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 for environmental conditions;
· 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 equipment in recent years, the boundaries between professional and household models have largely blurred, and today high-performance professional models are often used as household models, 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. At the moment, there are many systems and methods, principles and grounds for classifying computers. This paper presents the most common classifications of computers.
Thus, computers are classified by purpose (mainframe computers, minicomputers, microcomputers, 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 machines into generations was brought to life by the fact that during the short history of its development, computer technology has undergone a great evolution both in the sense of the elemental base (lamps, transistors, microcircuits, etc.), and in the sense of changes in its structure, the emergence of new capabilities, expanding the scope of application and 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 task that requires multiple solutions, and operate under special operating conditions. 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 the decimal number system 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. An 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.
Positional number systems allow you to write numbers. The elements of the PSS are symbols. For example, in the decimal number system the symbols 0, 1, ..., 9 are used. Let B be the base of the PSS, i.e. a number equal to the number of characters. For decimal SS. In PSS, a proper decimal fraction is represented as
where and are the number of digits before and after the decimal point, respectively.
Example.
In addition to decimal, binary, octal and hexadecimal SS are used. Binary SS uses the symbols and, octal - , and hexadecimal - .
Example.
Presentation of numerical information in a computer
To represent numbers in a computer, the binary number system is used. The number itself can be represented in various formats: as a natural number, as an integer, fixed point, floating point, BCD, etc.
Data Units
The units for measuring data volume are based on the binary number system.
Data units. Numbers in a computer are transmitted via wires (buses) or stored in memory cells. The wire can have either zero or high potential, and the memory cell can be in one of two stable states. The analogue of these states is a binary digit. One binary digit was assigned a new data unit, which was called bit.
The remaining non-system units are presented in table.
Table - Non-system units of data volume measurement
Representation of symbolic information in a computer. ASCII (American Standard Cods for Information Interchange) is used to represent character information in computer memory. This code consists of 7 bits. It can be used to encode characters. Character encoding is carried out using natural numbers from 0 to 127. Each character has its own number. The first code values from 0 to 31 are used for service characters. If these codes are used in the symbolic text of the program, they are not displayed on the screen and are considered spaces. Then come punctuation marks, special characters and operation signs, numbers, etc. Capital letters of the Latin alphabet begin with 65 and end with 90, and lowercase letters - from 97 to 122. If 8 bits are allocated for the character code, then another 128 numbers can be used to encode, for example, the Russian alphabet.
Windows 2000 uses the universal character encoding system UNICODE. 16 binary bits are used to encode characters. Various characters can be placed into this coding system, which is enough to accommodate the characters of the main languages of the planet.
Presentation of logical information in a computer. In Pascal, the character code is returned by the ord function. Under logical type is allocated 1 bit: ord (false) =0, ord(true) =1.
Variable length fields range in size from 0 to 256 bytes.
Coding of graphic data. The image on the monitor screen is formed by a system of luminous dots. It is called raster. Each point is characterized by coordinates, color and brightness. For black-and-white images, the standard gradation is 256 shades of gray, for which 1 byte is used for encoding.
It is believed that any color can be obtained by mixing red (Red), green (Green) and blue (Blue). This method of obtaining color is called RGB. If 8 bits are used for each color to gradate its intensity, then to set the color of one point you will need 24 bits, allowing you to get 2 24 = 16777216 different colors. This corresponds to the ability of the human eye to distinguish colors, so this way of representing graphic information is called full color (True Color).
If 16 bits are used for color encoding, then the method is called High Color.
If 8 bits are used for color encoding, then the encoding method is called index. Each number (index) is assigned its own color sample, which is placed in the reference table - palette.
Encoding of audio information. When reproducing sounds, the method of table-wave synthesis is used. Special tables contain the basic sound parameters of all major instruments in numerical form.
Concept of software (software). Software products are conventionally divided into three classes:
- - system software;
- - application programs;
- - programming technology tools.
System software ensures efficient and reliable operation of the computer, creates an effective operating environment for executing other programs, performs hardware diagnostics, copies, restores and archives files, and provides an operator interface.
The most common operating systems include MS DOS, Windows 95, OS/2, NetWare, Windows NT, Unix. The system includes basic And service software. Basic software includes operating system, shell and network system. Service software expands the capabilities of the basic software and provides computer diagnostics, virus protection, file archiving, disk and network maintenance.
Operating shells are programs that facilitate user communication with a computer. Shells can be text and graphic. Popular text shells for the MS DOS operating system include Norton Commander 5.0 (Symantec), XTree Gold 4.0, Norton Navigator, etc. The most popular graphical shells are Windows.
The programs included in the service software are called utilities, such as Norton Utilities (Symantec Corporation).
Application software packages include problem-oriented, computer-aided design, general purpose, integrated packages (Microsoft Office), office, desktop publishing systems, multimedia software. Problem-oriented ones include software for automated accounting, financial activities, personnel records, inventory and production management, banking information systems, etc. General-purpose application programs include DBMS, text and spreadsheet processors, and presentation graphics tools. Office PPPs include organizers, translation programs, and e-mail.
Modern computers represent one of the most significant achievements of human thought, the influence of which on the development of scientific and technological progress can hardly be overestimated.
Today, in addition to the usual computers with keyboards, monitors, and disk drives, the world of modern technology is filled with invisible computers - microprocessors, which are a computer in miniature.
In addition to the processing unit, it contains a control unit and even memory (internal memory cells). This means that the microprocessor is capable of autonomously performing all necessary actions with information.
Microprocessors have become widespread wherever control can be reduced to issuing a limited sequence of commands. Among them are: multi-user, equipped with many remote terminals and operating in time-sharing mode; built-in, which can control a machine, any subsystem of a car, or another device, being a small part of it. These embedded devices (called controllers) come in the form of small circuit boards.
Thus, computers created on the basis of a microprocessor (micro-computers) are indispensable in modern technology.
The use of microprocessors even 30 years ago was about 2000 different areas: production management (16%), scientific research, transport and communications (17%), information and computing technology (12%), military equipment (9%), household appliances ( 3%), training (2%), aviation and space (15%), utilities and urban services, banking, metrology, medicine (4%) and other areas.
Currently, their areas of application can be divided into groups.
Scientific and technical applications. They are characterized by a requirement for high performance. These are those areas of science and technology where the use of computers is extremely necessary: nuclear physics, meteorology, rocketry, medicine.
Data processing. This raises the requirement for a large storage capacity. This group solves problems in the areas of statistics, logistics, accounting, planning, ticket reservations, development of network diagrams, etc.
Modeling. Computers are used to model various complex phenomena in economics, automation, biology, military affairs, etc.
Production process management. In this case, the machine operates in the so-called real time, when arithmetic and logical operations are performed during the production processes themselves. The role of the control machine can be reduced to performing the following functions:
Fully informing the operator about the progress of the process;
Alarms when parameters essential to the process are outside acceptable limits;
Autonomous (without human intervention) control of the process.
Microprocessors have become widespread in manufacturing, where control can be reduced to issuing a limited sequence of commands. For example, the following areas of automation are being developed using microprocessor technology for control systems:
CNC machines plus robot;
CNC machines plus robot plus active dimensional control device;
CNC machines plus a robot plus an automatic diagnostic system with self-return.
Today, all modern equipment, both domestic and industrial, are complex technical systems implemented on the basis of microelectronics and computer technology.
Computing tools are the most important component of various technical devices: electronic equipment, washing machines, refrigerators, clothes dry cleaning machines and other technical devices for various purposes, including military ones. Thus, it is unthinkable to control a modern engine without the use of microprocessors - ensuring savings in fuel consumption, limiting the maximum speed, monitoring serviceability, etc.
The greatest effect of using microprocessors is achieved in the embedded version of its use, when they are built into devices, devices or machines. Currently, household refrigerators, automatic washing machines, microwave ovens, television receivers, VCRs and players with built-in microprocessors are used.
Thus, the use of microprocessors in equipment makes it possible to increase the productivity of heavy manual labor and improve the quality of goods and services. Integrating microprocessors into machines, equipment and devices will help solve complex problems of software control of technological processes.
Computers are used to perform a wide range of production tasks. For example, a dispatcher at a large plant has at his disposal an automated control system that ensures the uninterrupted operation of various units.
Computers are also used to control temperature and pressure during various manufacturing processes.
Computer-controlled robots are also used in factories, such as car assembly lines, that involve repetitive tasks such as tightening bolts or painting body parts.
Considering the use of computers in process control, we can identify a whole group of applications related to measurements and displays of the measured state. Computers turned out to be the information core of fundamentally new means of production; flexible production systems (GPS) and measuring systems.
The creation of computer-based control and measuring equipment, with which you can check products directly on the production line, is one of the new areas of application of computers in enterprises. The use of computers as control and measuring instruments is more cost-effective than the production in limited quantities of specialized complex devices with computing units. A great effect in mechanical engineering is achieved by GPS systems consisting of numerically controlled machines, automated warehouse and transport systems controlled by a computer.
In control systems for complex technological processes, the operation of a technological complex is monitored by numerous sensors and devices that measure process parameters (for example, the temperature and thickness of a rolled metal sheet), monitor the condition of equipment (for example, the temperature of turbine bearings) or determine the composition of raw materials and the finished product. There can be from several tens to several thousand such devices in one system.
Sensors constantly produce signals that change in accordance with the measured parameter (analog signals) to a communication device with a computer object, where the signals are converted into digital form and then processed by a computer according to a certain program. The computer compares the information received from the sensors with the specified results of the unit’s operation and generates control signals that are sent to the unit’s regulatory bodies. For example, if the sensors signal that the rolling mill sheet is coming out thicker than prescribed, the computer will calculate how far the rolling mill rolls need to be moved and send a corresponding signal to the actuator, which will move the rolls to the required distance.
One of the most important properties of a control system for complex technological processes is to ensure trouble-free operation of a complex technological complex. For this purpose, the possibility of diagnosing technological equipment is provided. Based on sensor readings, the system determines the current state of the units and trends in emergency situations and can give a command to operate in a lighter mode or stop altogether. In this case, the operator is provided with data on the nature and location of emergency areas.
Thus, the use of computers ensures better use of production resources, increased labor productivity, savings in raw materials, supplies and energy resources, the elimination of severe emergency situations, and an increase in the between-repair periods of equipment operation.
The computer is used in the technical equipment of self-service stores: purchases are passed through an optical scanning device, which reads the universal code applied to the purchase, by which the computer determines the price of this product, stored in the computer’s memory, and displays it on a small screen so that the buyer can see the cost your purchase. Once all selected items have passed through the optical scanning device, the computer immediately displays the total value of the items purchased.
Powerful computing systems are used in banking operations, which allows a large number of operations to be performed, including processing checks, recording changes in each deposit, accepting and disbursing deposits, processing loans, and transferring deposits from one account to another or from bank to bank.
In addition, the largest banks have automatic devices located outside the bank.
ATMs allow customers to avoid long lines at the bank and withdraw money from their account when the bank is closed.
The level of use of computers in medicine, which is becoming more and more automated, has increased enormously. Complex modern research in medicine is unthinkable without the use of computer technology.
Such studies include computed tomography, tomography using the phenomenon of nuclear magnetic resonance, ultrasonography, and studies using isotopes.
Expert systems are also widely used in medicine, the main purpose of which is medical diagnostics. Diagnostic systems are used to establish connections between disorders of the body and their possible causes.
In addition, the computer is used to develop various types of motor skills as part of simulators when teaching various professions: pilots, machinists, drivers and others.
So, the development of computer technology and the scope of its use are interconnected and interdependent processes.
On the one hand, the needs of the national economy stimulate the search by scientists for new ways to build computers, and on the other hand, the emergence of computers with greater functionality, with significantly improved performance, reliability, etc., creates the prerequisites for the continuous expansion of areas and the development of forms computer applications.
electronic computing microprocessor simulation
The speed of calculations, memory capacity, and complexity of algorithms for performing arithmetic operations depend on which number system will be used in the computer.
The fact is that for the physical representation (image) of numbers, elements are needed that can be in one of several stable states. The number of these states must be equal to the base of the number system used. Then each state will represent the corresponding digit from the alphabet of a given number system.
The decimal number system that is familiar to us is not the best for use in computers. To represent any number in the decimal system, ten different symbols are required. When implementing this number system in a computer, functional elements are required that have exactly ten stable states, each of which is assigned to a specific number. Thus, adding machines use rotating gears, for which ten stable positions are fixed. But the adding machine and other similar mechanical devices have a serious drawback - low performance.
The creation of electronic functional elements that have many stable states is difficult. The simplest from the point of view of technical implementation are the so-called two-position elements, capable of being in one of two stable states, for example:
· electromagnetic relay is closed or open;
· ferromagnetic surface is magnetized or demagnetized;
· electronic vacuum tube (for the first computers) is turned on or off;
· the magnetic core is magnetized in a certain direction or in the opposite direction;
· the transistor switch is in a conducting or locked state;
· a section of the surface of a magnetic storage medium is magnetized or demagnetized;
· a section of the surface of a laser disc reflects or does not reflect, etc.
One of these stable states can be represented by the number 0, the other by the number 1. There are other significant advantages associated with the binary system. It provides maximum noise immunity during the transmission of information both between individual nodes of the automatic device and over long distances. It performs arithmetic operations extremely simply and allows the use of Boolean algebra to perform logical transformations of information.
Thanks to these features, the binary system has become a standard in the construction of computers.
Octal and hexadecimal number systems are also widely used in computers. Information exchange between devices of most computers is carried out by transmitting binary words. Because of their large length and visual uniformity, it is inconvenient for a person to use such words. Therefore, specialists (programmers, engineers), both at the stages of compiling simple programs for microcomputers, their debugging, manual data input and output, and at the stages of development, creation, and configuration of computer systems, replace machine command codes, addresses and operands with equivalent values in octal or hexadecimal number system. As a result, the length of the original word is reduced by 3 or 4 times, respectively. This makes the information more convenient for review and analysis. Thus, the octal and hexadecimal number systems act as the simplest language of communication between a person and a computer, which is quite close to both the decimal number system familiar to humans and the binary “language” of a machine.
The computer uses binary only notation. All logic is based on the principle that there is a signal - 1, and there is no signal - 0. Everything else is a representation of numbers.
Quick transfer methods:
from binary to hexadecimal:
You split a binary number into four-bit segments and
0000 - 0h
0001 - 1h
0010 - 2h
0011 - 3h
0100 - 4h
0101 - 5h
0110 - 6h
0111 - 7h
1000 - 8h
1001 - 9h
1010 - Ah
1011 - Bh
1100 - Ch
1101 - Dh
1110 - Eh
1111 - Fh
so your number is in hexadecimal
1001 0101 0110 0111 - 9567h
Well, for octal you can figure it out yourself.
Answer: 75 10 = 1 001 011 2 = 113 8 = 4B 16.
3. Number systems used in computers. Convert from binary, octal and hexadecimal to decimal number systems.
