Main characteristics of a computer. Basic terms, definitions and concepts of computers. Computers and personal computers
Computer literacy presupposes an understanding of the five generations of computers, which you will receive after reading this article.
When they talk about generations, they first of all talk about the historical portrait of electronic computers (computers).
Photos in a photo album after a certain period of time show how the same person has changed over time. In the same way, computer generations represent a series of portraits of computing technology at different stages of its development.
The entire history of the development of electronic computing technology is usually divided into generations. Generational changes were most often associated with changes in the elemental base of computers and with the progress of electronic technology. This always led to increased performance and increased memory capacity. In addition, as a rule, changes occurred in the computer architecture, the range of tasks solved on a computer expanded, and the method of interaction between the user and the computer changed.
First generation computer
They were tube machines from the 50s. Their elemental base was electric vacuum tubes. These computers were very bulky structures, containing thousands of lamps, sometimes occupying hundreds of square meters of territory, consuming hundreds of kilowatts of electricity.
For example, one of the first computers was a huge unit, more than 30 meters long, contained 18 thousand vacuum tubes and consumed about 150 kilowatts of electricity.
Punched tapes and punched cards were used to enter programs and data. There was no monitor, keyboard or mouse. These machines were used mainly for engineering and scientific calculations not related to the processing of large volumes of data. In 1949, the first semiconductor device was created in the USA, replacing the vacuum tube. It got the name transistor.
Second generation computer
Transistors
In the 60s, transistors became the elemental base for second-generation computers. Machines have become more compact, more reliable, and less energy-intensive. The performance and capacity of internal memory have increased. External (magnetic) memory devices have received great development: magnetic drums, magnetic tape drives.
During this period, high-level programming languages began to develop: FORTRAN, ALGOL, COBOL. Compiling a program no longer depends on a specific car model; it has become simpler, clearer, and more accessible.
In 1959, a method was invented that made it possible to create transistors and all the necessary connections between them on one plate. The circuits obtained in this way became known as integrated circuits or chips. The invention of integrated circuits served as the basis for the further miniaturization of computers.
Subsequently, the number of transistors that could be placed per unit area of an integrated circuit approximately doubled every year.
Third generation computer
This generation of computers was created on a new element base - integrated circuits (ICs).
Microcircuits
Third-generation computers began to be produced in the second half of the 60s, when the American company IBM began producing the IBM-360 machine system. A little later, machines of the IBM-370 series appeared.
In the Soviet Union in the 70s, the production of machines of the ES (Unified Computer System) series began, modeled on the IBM 360/370. The operating speed of the most powerful computer models has already reached several million operations per second. On third-generation machines, a new type of external storage device appeared - magnetic disks.
Advances in the development of electronics led to the creation large integrated circuits (LSI), where several tens of thousands of electrical elements were placed in one crystal.
Microprocessor
In 1971, the American company Intel announced the creation of a microprocessor. This event was revolutionary in electronics.
Microprocessor is a miniature brain that works according to a program embedded in its memory.
By connecting a microprocessor with input-output devices and external memory, we got a new type of computer: a microcomputer.
Fourth generation computer
Microcomputers are fourth generation machines. Personal computers (PCs) are the most widespread. Their appearance is associated with the names of two American specialists: and Steve Wozniak. In 1976, their first production PC, Apple-1, was born, and in 1977, Apple-2.
However, since 1980, the American company IBM has become a trendsetter in the PC market. Its architecture has become the de facto international standard for professional PCs. The machines in this series were called IBM PC (Personal Computer). The emergence and spread of the personal computer in its significance for social development is comparable to the advent of book printing.
With the development of this type of machine, the concept of “information technology” appeared, without which it is impossible to do in most areas of human activity. A new discipline has emerged - computer science.
Fifth generation computer
They will be based on a fundamentally new element base. Their main quality should be a high intellectual level, in particular, speech and image recognition. This requires a transition from traditional von Neumann architectures to architectures that take into account the requirements of the tasks of creating artificial intelligence.
Thus, for computer literacy it is necessary to understand that at the moment four generations of computers have been created:
- 1st generation: 1946 creation of the ENIAC machine using vacuum tubes.
- 2nd generation: 60s. Computers are built on transistors.
- 3rd generation: 70s. Computers are built on integrated circuits (ICs).
- 4th generation: Started to be created in 1971 with the invention of the microprocessor (MP). Built on the basis of large integrated circuits (LSI) and super LSI (VLSI).
The fifth generation of computers is built on the principle of the human brain and is controlled by voice. Accordingly, the use of fundamentally new technologies is expected. Huge efforts have been made by Japan in developing the 5th generation computer with artificial intelligence, but they have not yet achieved success.
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 analogue) to standard computer systems that run control programs. In addition, 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.
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.
Main functional blocks of the 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 basic 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 of various types, and 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 Intel Pentium processors have 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 PCs to solve very complex problems in 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. Performs hundreds of different 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 input/output system. 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 a set of chips designed to support in a PC the functionality provided by the processor, OP, cache memory, disk and video memory and other components and to combine the components of the 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 information exchange operations. Each external device has its own controller.
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After receiving commands from the CPU, the controller performs maintenance operations on the 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). To quickly transfer small amounts of data, use floppy disks(floppy disks) that are inserted into a special drive - drive. The correct direction for feeding the floppy disk into the drive hole located on the front panel of the system unit is 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 are 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 speed. 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 differs from recording on magnetic disks in its very high density, and a standard CD can store approximately 650 MB of data. Οʜᴎ are distinguished by high reliability of information storage and durability (their predicted service life, if performed well, 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 PC components. The set of all buses is usually called the system backbone. 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 display text and graphic information 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 the important monitor parameters. The higher it is, the more information can be displayed on the screen, but the smaller the size of each individual dot, and therefore the smaller the visible size of the image elements.
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. Analogue technologies use cathode ray tube displays, while digital technologies 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 require support from drivers (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 sound speakers (some are 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 - network service providers - 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.
Personal computers. Differences between PCs and general and special purpose computers
Differences between PCs and general and special purpose computers. The structure of a modern desktop PC, which basically replicates the structure of a mainframe computer, differs from the latter in a wide variety of configurations of nodes and peripheral equipment. This diversity reflects the implementation of the principle of open architecture. Not only the company, but also the user himself can create any PC configuration necessary for his purposes within the capabilities of the PC motherboard.
PCs are also distinguished by the choice of central processor, the number and types of ports, which are the mating parts of the connectors with which peripherals are connected to the PC - external memory devices and various technical means of input and output of information (monitor, mouse, keyboard, etc.), the presence of audiovisual configuration components - sound and video cards, the presence of wireless ultrasonic or infrared communication devices, etc.
A careful examination of the modern PC and peripheral market (exhibitions, trade organizations, etc.) shows that all PCs are equipped with advanced devices. RAM reaches hundreds and thousands of megabytes, external memory - tens and hundreds of gigabytes. PCs are equipped with powerful processors (speed - from one to three or more gigahertz), motherboards with a large number of ports (more than ten), powerful video and sound cards, network cards, modems and fax modems, etc. In motherboards The functions of a video, sound and network card are often integrated, which by reducing the detachable connections of PC nodes increases the reliability of its operation.
Compared to the PCs of the end of the last century, the PCs of the first years of the new millennium in terms of power, degree of miniaturization, and ergonomic perfection (size, weight, design) reached the indicators predicted for fifth-generation computers. Portable PCs (laptops) began to be positioned as substitutes for desktop PCs. The industry produces full-scale graphics stations in laptop format, as well as desktop PCs, in which all components, including the monitor, are integrated in one unit that takes up the same space as a laptop.
A specific modern graphics station in laptop format can have very high parameters and a wide range of peripherals: an internal modem, a wireless port for access to a local network (and through it to the Internet), a built-in video camera, a microphone and two speakers. The set of ports allows you to: connect a second monitor or, instead, a TV, as well as an external microphone and audio speakers, a printing device, a scanner, external photo and video cameras, game controllers, a second keyboard and a number of other devices, most of which equip a graphics station simultaneously, and not in replacement mode. When this PC is saturated with software applications, it can be interpreted not only as a graphic, but also a multimedia, music station - a workstation for a composer, designer, planner, etc.
Currently, users are armed with large-capacity flash memory (up to 1-2 GB) that does not require power supply. Initially, this silicon chip memory was used to record music in miniature MP3 players. Today, not only sound is recorded on flash memory (Sony's Memory Strick memory - up to 80 minutes of music), but also images and texts. It is also included in printers, digital video cameras, cameras and many other products with automatic elements.
Factors that determined the mass popularity of PCs. The special role of PCs in the formation and functioning of modern screen culture is determined by their accessibility to the general public, mass distribution, device perfection and variety of models and software. Of course, the main reason for the mass popularity of PCs is the market mechanisms of the capitalist economy. However, certain features of PC design and software architecture greatly contribute to their distribution and improvement.
We will limit ourselves to two design principles first introduced by IBM when creating their PCs (1981), which ensured the mass production and distribution of PCs.
The principle of open architecture, when IBM “simply transferred” the modularity of the computer design to the PC, became a powerful driver of their development and distribution. PC components began to be developed by many companies, and not by one, as is usual for computers with a closed (monolithic) architecture. It has become possible to completely assemble a PC by any company and even by an individual user. PCs from other companies have become two or three times cheaper than IBM's. PC models in the IBM architecture are today produced by many companies. These models are fully compatible with IBM PCs. There is a term: “IBM-compatible PCs”.
The second principle used in the logic of building software applications was the principle of “top-down compatibility” of PC nodes and the PC itself as a whole. This principle means that each subsequent version (model) of a PC or its individual component only adds new technical capabilities to the PC. The new ability to “run” old programs on new versions of a PC (but not vice versa) was also a powerful driver of its spread.
PC peripheral equipment. This includes technical means of input and output of information, external memory devices and technical means of teleprocessing of data. Computer peripherals are developing extremely quickly. It exists in a huge variety of models and types, defining both the functionality of the PC and the way the user communicates with the PC directly and at a distance.
Information input devices into a PC include a keyboard, mouse, scanner, microphone, game controllers, recorders, digital photo and video cameras, video and audio recorders with an analogue to digital signal converter, etc., connected to the PC by cables, which are increasingly being replaced by called wireless connections on different physical bases.
The main device for entering information into a PC is the keyboard. The ergonomics of keyboards, produced in several modifications, are important. Extremely “soft” keyboards with plastic pins have been replaced by keyboards with a click that clearly registers the keystroke.
There are touch keyboards without mechanical elements, usually used in industry due to their exceptional durability and due to the impossibility of foreign objects (paper clips, cigarette ash, etc.) getting “between the keys” (instead of which pads made of touch foil are used).
Keyboards contain different numbers of keys. The XT keyboard has 83 keys (sometimes 85). A “system poll” key has been added to the AT keyboard. The MFII (Multifunction) keyboard has 102 keys. Special keyboards contain additional devices for reading bar codes, with a device for outputting Braille characters for blind users, etc.
Another important means of entering information into a computer is the mouse. The cursor coordinates are received from the mouse via a cable or wirelessly from a miniature radio transmitter, or via the light beam of an optical mouse. Using the left mouse button, you select (click) an object - an icon or another - and “drag” it (without releasing the button) across the screen. Double-clicking activates an object - launches the command or program symbolized by the icon.
A joystick is a game controller that is mainly used to control a computer game. Usually there are two ports for joysticks if the PC is oriented as a gaming one.
To draw on the screen, there is a graphics tablet and a graphics pen (pencil). An active coordinate grid is “hardwired” into the tablet, so that a graphic pen, similar to a mouse, displays a signal - a drawing point or other tool - on the screen. For the tablet to work, a special program must be loaded into the PC.
A digital video camera, otherwise called a Web camera, is often built into laptops and used for network video conferencing. The image quality from the web camera still leaves much to be desired.
The image in a digital camera is perceived by a matrix of photo sensors, which transmits signals to the camera's memory. These images can then be displayed on a PC screen, or printed offline on an inkjet photo printer.
Scanners are used to enter texts, photos and graphic images, barcodes, etc. into the PC. Another type of input is carried out from an intermediate medium with large flash memory - a portable hard drive, magnetic or optical CDs; in this case, the input device is the disk drive.
Devices for outputting information from a digital computer include means for outputting alphanumeric data, means for outputting graphics, and integrated ones. From the very beginning of the development of computer technology - punching and printing devices, plotters (plotters) of many types, monitors (displays), which are also a means of managing data input (means of communication), have received powerful development. Dot matrix printers of the 1970s and 1980s In most cases, digital computers were replaced by inkjet computers, as well as laser ones, based on the principles of electrography, similar to a copier such as a copier.
Monitors based on a cathode ray tube have begun to be intensively replaced by “thin” display models: LCD based on liquid crystal elements, PDP based on plasma elements, which significantly reduces the size and increases the ergonomics of desktop PCs. Portable (laptop), pocket computers and virtual helmets are equipped with LCD displays. (PDP displays are not used in them due to high power consumption.)
Multimedia technology. Multimedia (multimedia) technology combines text, graphics, music, speech, and moving images into a PC. The retail network and companies that produce and assemble PCs, for their purposes, divide them into office, home and multimedia (centers). In light of the rapid growth of PC parameters and their capabilities, including the integration of all types of information environments (media), any such division loses its meaning, since all multimedia functions become available even to an inexpensive PC.
The identification of computer science as an independent field of human activity is primarily associated with the development of computer technology.
A computer is a “calculator”, i.e. computing device. The fundamental difference between computers and adding machines and other calculating devices is that adding machines can perform only individual operations (addition, subtraction, etc.), while computers allow complex sequences of computational operations to be performed without human intervention according to a predetermined instruction - a program. In addition, computers contain memory to store data.
The history of the computer is closely connected with human attempts to make it easier to automate large volumes of calculations. Even simple arithmetic operations with large numbers are difficult for the human brain. Therefore, already in ancient times, the simplest calculating device, the abacus, appeared. In the seventeenth century, the slide rule was invented to facilitate complex mathematical calculations. In 1642, Blaise Pascal designed an eight-bit adding mechanism. Two centuries later, in 1820, the Frenchman Chal de Calmar created an adding machine capable of multiplication and division. This device has firmly taken its place on accounting tables.
All the basic ideas that underlie the operation of computers were outlined back in 1833 by the English mathematician Charles Babbage. He developed a design for a machine for performing scientific and technical calculations, where he foresaw the devices of a modern computer, as well as its tasks. To input and output data, Babbage proposed using punched cards, sheets of thick paper with information printed using holes. At that time, punch cards were used in the textile industry. Such a machine had to be controlled by software.
Babbage's ideas began to be actually implemented at the end of the 19th century. In 1888, the American engineer Herman Hollerith designed the first electromechanical calculating machine. This machine, called a tabulator, could read and sort statistical records encoded on punched cards. In 1890, Hollerith's invention was used in the 11th US Census. The work that 500 employees performed over seven years was completed by Hollerith with 43 assistants on 43 tabulators in one month.
In 1896, Herman Hollerith created the COMPUTING TOBULATING RECORDING COMPANY, which became the basis for the future company IBM (International Business Machines Corporation), which made a huge contribution to the development of world computer technology.
In the 40s of the XX century. several groups of researchers repeated Babbage's attempt. Thus, in the USA in 1943, at one of the IBM enterprises, Howard Aiken created a computer called “Mark - 1”, which worked on the basis of electromechanical relays. It was a monster weighing 35 tons.
"Mark-1" was based on the use of electromechanical relays and operated with decimal numbers encoded on punched tape. The machine could manipulate numbers up to 23 digits long. It took her 4 seconds to multiply two 23-bit numbers.
But electromechanical relays did not work fast enough, so at the same time a group of specialists led by John Mauchly and Presper Eckert began to construct an ENIAK computer based on vacuum tubes, which worked a thousand times faster than Mark 1. Its weight was 30 tons, it required 170 square meters of space to accommodate it. Instead of thousands of electromechanical parts, ENIAC contained 18,000 vacuum tubes. The machine counted in the binary system and performed 5000 addition operations or 300 multiplication operations per second.
In 1945, mathematician John von Neumann was brought in to work and prepared a report on this computer. In his report, von Neumann clearly and simply formulated the general principles of the functioning of computers.
And to this day, the vast majority of computers are made in accordance with the principles that John von Neumann outlined in his report in 1945:
Program control principle.
Data processing is carried out in accordance with a pre-compiled program. Discreteness principle representations and transformations information
. Information in the memory is represented in the form of binary words, and the operation of the machine consists of a sequence of individual actions.
Targeting principle.
To designate words stored in memory, addresses are used - also binary words, indicating the numbers of the corresponding memory cells. The principle of unity of commands and data
(operands). The same machine word can be both a command and an operand.
The function a word performs depends on where it is placed by the control program.
Feedback principle
In 1959, integrated circuits (chips) were invented, in which all electronic components, along with conductors, were placed inside a silicon wafer. The use of chips in computers makes it possible to shorten the paths of current during switching, and the speed of calculations increases tens of times. The dimensions of the machines are significantly reduced. The appearance of the chip marked the birth of the third generation of computers.
By the early 1960s, computers were widely used for processing large amounts of statistical data, performing scientific calculations, solving defense problems, and creating automated control systems. The high price, complexity and high cost of maintaining large computers limited their use in many areas. However, the process of computer miniaturization allowed the American company DIGITAL EQUIPMENT to release the PDP-8 minicomputer at a price of 20 thousand dollars in 1965, which made the computer accessible to medium and small commercial companies.
In 1970, another important step was taken towards the personal computer. INTEL employee Edward Hoff created the first microprocessor by placing several integrated circuits on a single silicon chip. The integrated circuit was similar in function to the central processing unit of a large computer. This is how the first microprocessor Intel-4004 appeared, the size of which did not exceed 3 cm.
In 1974, several companies announced the creation of a personal computer based on the Intel-8008 microprocessor, i.e. a device that performs the same functions as a large computer, but is designed for one user.
An important contribution to the development of computers was made by IBM. In 1981, IBM released the IBM PC, which was based on the principle of open architecture. IBM did not make its computer a single all-in-one device and did not protect its design with patents. Instead, she assembled the computer from independently manufactured parts and did not keep the specifications of those parts and how they were connected a secret. This led to the fact that many companies stopped being content with the role of manufacturers of components for the IBM PC and began to assemble computers compatible with the IBM PC themselves. Users were able to independently upgrade their computers and equip them with additional devices. Competition among manufacturers of IBM PC-compatible computers has led to cheaper prices and rapid improvements in their characteristics, and an increase in the popularity of IBM PC-compatible computers.
Despite the fact that IBM PC-compatible personal computers are the most widely used type of computer, their information processing capabilities are still limited and their use is not justified in all situations. In addition to IBM PC-compatible personal computers, there are:
Supercomputer- These are computers designed to solve problems that require enormous amounts of computation. The main consumers of supercomputers are the military, meteorologists, geologists and many other scientists.
Mainframes or mainframe computers designed to process large amounts of information. They are distinguished by exceptional reliability, high performance and very high throughput of I/O channels. Thousands of terminals can connect to them.
Minicomputer- These are computers that occupy an intermediate position between personal computers and mainframes.
Computers type Macintosh- This is the only widespread type of personal computer that is not compatible with the IBM PC.
Pocket computers or personal electronic assistants are small computers weighing about 300-500 grams.
Household computers, which are built into various household appliances and devices, for example, a washing machine, etc.
