Structural organization of the PC. Architecture of modern high-performance computers - file n1.doc Functional structure of a computer
The word "computer" means "calculator", i.e. computing device. The need to automate data processing, including calculations, arose a long time ago. Many thousands of years ago, counting sticks, pebbles, etc. were used for counting. etc. More than 1,500 years ago (and perhaps much earlier), abacus began to be used to make things easier.
Thus, attempts to automate computing processes were made at all stages of the development of human civilization.
VI century BC e. — Pythagoras introduced the concept of number as the basis of everything on earth.
V century BC e. - Salamis Island - the first abacus counting device.
IV century BC e. — Aristotle developed deductive logic.
III century BC e. — Diophantus of Alexandria wrote “Arithmetic” in 13 books.
9th century — Al-Khorezmi generalized the achievements of Arabic mathematics and introduced the concept of algebra.
XV century — Leonardo da Vinci developed a design for a calculating machine to perform operations on 12-bit numbers.
XVI century - Russian abacus with a 10-digit number system was invented.
XVII century - England - slide rules.
The beginning of the development of computer technology is considered to be with Blaise Pascal, who in 1642. invented a device that mechanically performs the addition of numbers.
The next milestone result was achieved by the outstanding German mathematician and philosopher Gottfried Wilhelm Leibniz, who in 1672 expressed the idea of mechanical multiplication without sequential addition. A year later, he presented a machine that could mechanically perform four arithmetic operations to the Paris Academy. Leibniz's machine required a special table to install, as it had impressive dimensions: 100´ 30 ´ 20 centimeters.
In 1812, the English mathematician Charles Babbage began working on the so-called difference engine, which was supposed to calculate any functions, including trigonometric ones, and also compile tables.
A native of Alsace, Karl Thomas, the founder and director of two Parisian insurance companies, designed a calculating machine in 1818, focusing on the manufacturability of the mechanism, and called it an adding machine.
In the first decades of the 20th century, designers drew attention to the possibility of using new elements in counting devices - electromagnetic relays. In 1941, German engineer Konrad Zuse built a computing device that operated on such relays.
Almost simultaneously, in 1943, the American Howard Aiken, with the help of Babbage’s work based on 20th century technology - electromechanical relays - was able to build the legendary Harvard Mark-1 (and later also Mark-2) at one of the IBM enterprises. “Mark-1” was 15 meters long and 2.5 meters high, contained 800 thousand parts, had 60 registers for constants, 72 storage registers for addition, a central multiplication and division unit, and could calculate elementary transcendental functions. The machine worked with 23-digit decimal numbers and performed addition operations in 0.3 seconds and multiplication operations in 3 seconds.
Work on creating the first electronic computer was apparently started in 1937 in the USA by Professor John Atanasov, a Bulgarian by birth. This machine was specialized and intended to solve problems of mathematical physics. During his development, Atanasov created and patented the first electronic devices, which were subsequently used quite widely in the first computers. Atanasov’s project was not completely completed, but three decades later, as a result of a trial, the professor was recognized as the founder of electronic computing technology.
Beginning in 1943, a group of specialists led by Howard Aiken, J. Mauchly and P. Eckert in the USA began to design a computer based on vacuum tubes, rather than on electromagnetic relays. This machine was called ENIAC (Electronic Numeral Integrator And Computer) and it worked a thousand times faster than the Mark-1. ENIAC contained 18 thousand vacuum tubes and occupied an area of 9´
15 meters, weighed 30 tons and consumed power of 150 kilowatts.
In 1945, the famous mathematician John von Neumann was involved in the creation of a computer, who prepared a report on this machine. In this report, von Neumann clearly and simply formulated the general principles of the functioning of universal computing devices, i.e. computers. This was the first operational machine built on vacuum tubes and was officially put into operation on February 15, 1946. They tried to use this machine to solve some problems prepared by von Neumann and related to the atomic bomb project. She was then transported to Aberdeen Proving Ground, where she operated until 1955.
ENIAC became the first representative of the 1st generation of computers. Any classification is conditional, but most experts agreed that generations should be distinguished based on the elemental base on which the machines are built. Thus, the first generation appears to be tube machines.
The structure and operation of a computer according to the “von Neumann principle”. Let us note the most important of them:
keyboard for entering alphanumeric information and commands.
For ease of control, manipulators such as “mouse” and “joystick” are also used (the latter, mainly for games).
Of these parts of the computer, the system unit looks the least impressive; it is the “main” part of it. All the main components of the computer are located in it:
electronic circuits that control the operation of the computer (microprocessor, RAM, device controllers, etc.);
a power supply that converts network power into low-voltage direct current supplied to the computer's electronic circuits;
floppy disk drives (or drives) used for reading and writing to floppy disks (floppy disks);
a hard magnetic disk drive designed for reading and writing to a non-removable hard magnetic disk (hard drive);
Other devices.
Rice. 4. Types of system units
The heart of the computer is undoubtedly the central processor, located on the motherboard inside the system unit. It is an ultra-large integrated circuit consisting of millions of transistors inside. The processor is capable of executing a large number of external commands and processing information received in the form of electrical signals. To speed up mathematical calculations, another chip is used - a mathematical coprocessor, which very significantly increases the speed of performing mathematical operations (calculating sines, cosines, logarithms, etc.). 
Rice. 5. System unit with the housing cover removed
The speed of the processor is determined by its structure (circuitry), as well as the external clock frequency, which is generated by the pulse generator on the motherboard. System (motherboard) board is the main board of the computer on which the microprocessor, RAM, cache memory, buses, and controllers are located.
To store executable programs and source data, to process and record intermediate and final results, the computer has random access memory (RAM). It is from this that the processor takes programs and source data for processing. This memory received the name “RAM” because it works very quickly, so that the processor practically does not have to wait when reading data from memory or writing to memory. When the computer is turned off, rebooted, or random power failures, the entire contents of the RAM are erased. Consequently, when typing any data, texts, etc. it is necessary to periodically write intermediate data to a hard disk or floppy disk.
To speed up access to RAM, modern high-speed computers use special “ultra-fast” static memory, which is called cache memory and is like a buffer between a very fast processor and slower RAM.
To connect the processor and RAM with external devices: keyboard, monitor, disk drives, etc., special electronic circuits or boards are used. In this case, the exchange of information between RAM and devices (i.e., input-output) does not occur directly: there are two intermediate links between any device and RAM:
1. Each device has its own electronic circuit that controls it. This circuit is called a controller, or adapter. Some controllers (for example, a disk controller) can control multiple devices at once)
2. All controllers (adapters) interact with the microprocessor and RAM through the system data transfer bus (bus). Nowadays, most manufactured computers are equipped with PCI and ISA buses.
One of the controllers that is present in almost every computer is the I/O port controller, which comes in the following types: parallel, serial, game.
An important element of a computer is the video adapter (or video card), which is used to generate video signals that display information on the monitor screen. The video card receives commands from the microprocessor to form an image, constructs this image in its service memory - video memory, and at the same time converts the contents of the video memory into a signal supplied to the monitor - video signal
A computer monitor (display) is designed to display text and graphic information on the screen. The modern type of monitors and, accordingly, video card is SVGA.
To permanently store information necessary while working with a computer, hard disk drives are used. They usually store operating system programs and files, various software packages, document editors, computer games and much more. The system unit may also include: drives (on laser disks - CD-ROM; internal on magnetic tape - streamer); sound card for reproducing various sound effects; internal fax modem; network cards.
Almost every computer has at least one floppy drive for floppy disks, which allow you to transfer documents and programs from one computer to another. The operating system and various programs can be loaded from floppy disks.
To power all devices running in the system unit, there is a powerful switching power supply.
In order for all electronic and mechanical devices to interact properly with each other, they must be controlled by special programs. Programs for internal testing of the monitor (POST - procedure, Power-On-Self-Test), initializing the video adapter and loading the operating system from disk, as well as programs for performing basic functions for managing I/O devices are stored on the motherboard in a special chip - read-only memory device.
The collection of these microprograms is called.(BIOS or basic input-output system). To change and remember computer configuration parameters, the BIOS has a special configuration program – SETUP. The parameters themselves are stored in a separate CMOS memory chip, which is powered by a special battery on the motherboard.
To work with many modern programs, it is almost mandatory to use a mouse or another device that replaces it, i.e. pointing devices, as they allow you to point to certain elements on the computer screen.
A mouse is a manipulator that is a small box with several buttons that easily shrinks in the palm of your hand. When you move the mouse across the surface on the monitor screen, the mouse pointer (usually an arrow) moves accordingly. When it is necessary to perform this or that action, the user presses one or another mouse button.
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Nossiter J. Microsoft Exel 2002 – M.: Dialectics, 2003. Organization and use of corporate systems ORGANIZATION AND PRINCIPLES OF WEB SITE CONSTRUCTION
machines using electronic elements should operate not in the decimal, but in the binary number system;
the program, like the source data, must be located in the machine’s memory;
the program, like numbers, must be written in binary code;
the difficulties of the physical implementation of a storage device, the speed of which corresponds to the speed of operation of logical circuits, require a hierarchical organization of memory (that is, the allocation of RAM, intermediate and long-term memory);
an arithmetic device (processor) is constructed on the basis of circuits that perform the addition operation; the creation of special devices for performing other arithmetic and other operations is impractical;
The machine uses a parallel principle of organizing the computational process (operations on numbers are performed simultaneously across all digits).
The first computer to embody von Neumann's principles was built in 1949 by the English researcher Maurice Wilkes. Since then, computers have become much more powerful, but the vast majority of them are made in accordance with the principles that John von Neumann outlined in his 1945 report.
New cars of the first generation replaced each other quite quickly. In 1951, the first Soviet electronic computer MESM, with an area of about 50 square meters, began operation.
In 1952, the American EDWAC machine was born.
In 1952, Soviet designers commissioned the BESM, the fastest machine in Europe, and the following year, Strela, the first high-class production machine in Europe, began operating in the USSR. Among the creators of domestic cars, the names of S.A. should be mentioned first. Lebedeva, B.Ya. Bazilevsky, I.S. Bruka, B.I. Rameeva, V.A. Melnikova, M.A. Kartseva, A.N. Myamlina. In the 50s, other computers appeared: “Ural”, M-2, M-3, BESM2, “Minsk1” - which embodied more and more progressive engineering solutions.
The projects and implementation of the Mark-1, EDSAC and EDVAC machines in England and the USA, MESM in the USSR laid the foundation for the development of work on the creation of computers of vacuum tube technology - serial computers of the first generation. The development of the first electronic production machine, UNIVAC (Universal Automatic Computer), began around 1947 by Eckert and Mauchli. The first model of the machine (UNIVAC-1) was built for the US Census Bureau and put into operation in the spring of 1951. The synchronous, sequential computer UNIVAC-1 was created on the basis of the ENIAC and EDVAC computers. It operated with a clock frequency of 2.25 MHz and contained about 5,000 vacuum tubes.
Compared to the USA, USSR and England, the development of electronic computer technology in Japan, Germany and Italy was delayed. The first Japanese Fujik machine was put into operation in 1956; mass production of computers in Germany began only in 1958.
Semiconductors became the elemental base of the second generation. Without a doubt, transistors can be considered one of the most impressive miracles of the 20th century.
A patent for the discovery of the transistor was issued in 1948 to the Americans D. Bardeen and W. Brattain, and eight years later they, together with the theorist W. Shockley, became Nobel Prize laureates.
The first on-board computer for installation on an intercontinental rocket, Atlas, was put into operation in the United States in 1955. The machine used 20 thousand transistors and diodes and consumed 4 kilowatts.
In 1956, IBM developed floating magnetic heads on an air cushion. Their invention made it possible to create a new type of memory - disk storage devices, the importance of which was fully appreciated in the subsequent decades of the development of computer technology. The first disk storage devices appeared in the IBM-305 and RAMAC machines.
The first mass-produced mainframe computers with transistors were released in 1958 simultaneously in the USA, Germany and Japan.
In the Soviet Union, the first lampless machines “Setun”, “Razdan” and “Razdan2” were created in 1959-1961. In the 60s, Soviet designers developed about 30 models of transistor computers, most of which began to be mass-produced. The most powerful of them, Minsk32, performed 65 thousand operations per second. Entire families of vehicles appeared: “Ural”, “Minsk”, BESM.
The record holder among second-generation computers was BESM6, which had a speed of about a million operations per second - one of the most productive in the world. The architecture and many technical solutions in this computer were so progressive and ahead of their time that it was successfully used almost to our time.
Especially for the automation of engineering calculations at the Institute of Cybernetics of the Academy of Sciences of the Ukrainian SSR under the leadership of Academician V.M. Glushkov developed the MIR (1966) and MIR-2 (1969) computers. An important feature of the MIR-2 machine was the use of a television screen for visual control of information and a light pen, with which it was possible to correct data directly on the screen.
Priority in the invention of integrated circuits, which became the elemental base of third-generation computers, belongs to the American scientists D. Kilby and R. Noyce, who made this discovery independently of each other. Mass production of integrated circuits began in 1962, and in 1964 the transition from discrete to integrated elements began to rapidly occur. ENIAC size 9 mentioned above´
15 meters in 1971 could be assembled on a plate of 1.5 square centimeters. The transformation of electronics into microelectronics began.
Despite the successes of integrated technology and the advent of minicomputers, large machines continued to dominate in the 60s. Thus, the third generation of computers, originating within the second, gradually grew out of it.
The first mass series of machines based on integral elements began to be produced in 1964 by IBM. This series, known as the IBM-360, had a significant impact on the development of computer technology in the second half of the 60s. It united a whole family of computers with a wide range of performance, and compatible with each other. The latter meant that it became possible to link machines into complexes, and also to transfer programs written for one computer to any other in the series without any modifications. Thus, for the first time, a commercially viable requirement for standardization of computer hardware and software was identified.
Since the second half of the 60s, the Soviet Union, together with the CMEA countries, began to develop a family of universal machines similar to the ibm-360 system. In 1972, mass production began of the starting, least powerful model of the Unified System - the ES-1010 computer, and a year later - five other models. Their performance ranged from ten thousand (EC-1010) to two million (EC-1060) operations per second.
As part of the third generation, a unique machine “ILLIAK-4” was built in the USA, which in its original version was planned to use 256 data processing devices made on monolithic integrated circuits.
The beginning of the 70s marks the transition to fourth-generation computers - very large-scale integrated circuits (VLSI). Another sign of a new generation of computers is dramatic changes in architecture.
The fourth generation technology gave birth to a qualitatively new computer element - the microprocessor. In 1971, they came up with the idea of limiting the capabilities of the processor by introducing into it a small set of operations, the microprograms of which must be previously entered into permanent memory.
Of the large fourth-generation computers based on ultra-large integrated circuits, the American machines “Krey-1” and “Krey-2”, as well as the Soviet models “Elbrus-1” and “Elbrus-2”, stood out especially well. Their first samples appeared at approximately the same time - in 1976. All of them belong to the category of supercomputers, as they have the characteristics that are extremely achievable for their time and are very expensive.
The fourth generation machines made a departure from the von Neumann architecture that had been the leading feature of the vast majority of all previous computers.
Although personal computers belong to the 4th generation computers, the possibility of their widespread distribution, despite the achievements of VLSI technology, would remain very small.
In 1970, an important step was taken on the path to a personal computer - Marchian Edward Hoff from Intel designed an integrated circuit similar in its functions to the central processor of a large computer. This is how the first Intel 4004 microprocessor appeared, which was released for sale in 1971. It was a real breakthrough, because the Intel 4004 microprocessor, less than 3 cm in size, was more productive than the giant machines of the 1st generation. True, the capabilities of the Intel 4004 were much more modest than those of the central processor of large computers of that time - it worked much slower and could process only 4 bits of information simultaneously (processors of large computers processed 16 or 32 bits simultaneously), but it also cost tens of thousands times cheaper. But the growth in microprocessor performance was not long in coming.
The first mass-produced personal computer was the Altair-8800, created in 1974 by a small company in Albuquerque, New Mexico.
In 1981, the first version of the operating system for the IBM PC computer, MS DOS 1.0, appeared. Subsequently, as IBM PC computers improved, new versions of DOS were released, taking into account the new capabilities of computers and providing additional convenience to the user.
In August 1981, a new computer called the IBM Personal Computer was officially introduced to the public and soon after that it gained great popularity among users. The IBM PC had 64 KB of RAM, a tape recorder for loading/saving programs and data, a floppy drive and a built-in version of the BASIC language.
After one or two years, the IBM PC computer took a leading position in the market, displacing 8-bit computer models.
A new generation of microprocessors replaces the previous one every two years and becomes obsolete in 3–4 years. The microprocessor, together with other microelectronic devices, makes it possible to create fairly cost-effective information systems.
November 8, 1993 – Windows for Workgrounds 3.11 released. It provides more complete compatibility with NetWare and Windows NT; In addition, many changes were made to the OS architecture aimed at improving performance and stability, which later found their way into Windows 95. The product was much more well received by corporate America.
In 1993, the first Pentium processors appeared with frequencies of 60 and 66 MHz - these were 32-bit processors with a 64-bit data bus.
Since that time, computers have been developing at a tremendous pace. The operating frequency of the processes has already reached 3.5 GHz, and the RAM capacity is about 8 GB.
2.
2.1. Concept and general characteristics of the functional structure of a computer
The variety of modern computers is very large. But their structures are based on general logical principles that make it possible to distinguish the following main devices in any computer:
memory (storage device, memory), consisting of renumbered cells;
a processor including a control unit (CU) and an arithmetic-logical unit (ALU);
input device;
output device.
These devices are connected by communication channels through which information is transmitted.
Rice. 1. General computer diagram
Memory functions:
receiving information from other devices;
remembering information;
– provision of information on request to other devices of the machine.
Processor functions:
processing data according to a given program by performing arithmetic and logical operations;
software control of the operation of computer devices.
The part of the processor that executes instructions is called an arithmetic logic unit (ALU), and the other part that performs device control functions is called a control unit (CU).
Usually these two devices are distinguished purely conditionally; they are not structurally separated.
The processor contains a number of specialized additional memory cells called registers.
The register performs the function of short-term storage of a number or command.
The first person to formulate the basic principles of the functioning of universal computing devices, i.e. computers, was the famous mathematician John von Neumann.
First of all, a modern computer must have the following devices:
an arithmetic-logical device that performs arithmetic and logical operations;
a control device that organizes the process of program execution;
a storage device, or memory for storing programs and data;
external devices for input/output of information.
In general terms, the operating principle of a computer can be described as follows.
First, using some external device, a program is entered into the computer's memory. The control device reads the contents of the memory cell where the first instruction(s) of the program is located and organizes its execution. This command can perform arithmetic or logical operations, read data from memory to perform arithmetic or logical operations or write their results to memory, input data from an external device into memory, or output data from memory to an external device
Typically, after executing one command, the control device begins executing the command from the memory cell that is located immediately after the command just executed. However, this order can be changed using control transfer (jump) instructions. These commands indicate to the control device that it should continue executing the program, starting from the command contained in some other memory location. Such a “jump” or transition in a program may not always be performed, but only when certain conditions are met, for example, if some numbers are equal, if the previous arithmetic operation resulted in zero, etc. This allows you to use the same sequences of commands in a program many times (i.e. organize loops), execute different sequences of commands depending on the fulfillment of certain conditions, etc., i.e. create complex programs.
Thus, the control device executes the program instructions automatically, i.e. human intervention. It can exchange information with RAM and external devices of the computer. Because external devices typically operate much slower than the rest of the computer, the control device may pause program execution until an I/O operation with the external device completes. All results of the executed program must be output to external devices of the computer, after which the computer proceeds to wait for any signals from external devices.
In modern computers, the arithmetic-logical unit and the control unit are combined into a single device - the central processor. In addition, the process of program execution can be interrupted to perform urgent actions related to received signals from external computer devices—interrupts.
Many high-speed computers perform parallel processing on multiple processors.
However, most modern computers conform in basic terms to the principles laid out by von Neumann.
2.2. Structural organization
Let's look at the design of a computer using the example of the most common computer system - a personal computer.
Personal computers are usually designed based on the principle of open architecture.
The principle of open architecture is as follows:
Only the description of the operating principle of the computer and its configuration (a certain set of hardware and connections between them) are regulated and standardized. Thus, a computer can be assembled from individual components and parts designed and manufactured by independent manufacturers;
The computer is easily expanded and upgraded due to the presence of internal expansion slots into which the user can insert a variety of devices that meet a given standard, and thereby configure the machine according to his personal preferences.
Rice. 2 General structure of a personal computer with connected peripheral devices
In order to connect different computer devices to each other, they must have the same interface (English interface from inter - between, and face - face).
An interface is a means of connecting two devices, in which all physical and logical parameters are consistent with each other.
If the interface is generally accepted, for example, approved at the level of international agreements, then it is called standard.
Each of the functional elements (memory, monitor or other device) is associated with a bus of a certain type - address, control or data bus.
Rice. 3. Connection diagram of peripheral device interfaces
Ports are also called standard interface devices: serial, parallel and game ports (or interfaces).
The serial port exchanges data with the processor byte by byte, and with external devices - bit by bit. The parallel port receives and sends data byte by byte.
The serial port is usually used to connect slow or fairly remote devices, such as a mouse and modem. Faster devices such as a printer and scanner are connected to the parallel port. A joystick is connected through the game port. The keyboard and monitor are connected to their own specialized ports, which are simply connectors.
The main electronic components that determine the processor architecture are located on the main computer board, which is called the system board or MotherBoard. And controllers and adapters of additional devices, or these devices themselves, are made in the form of expansion boards (DaughterBoard - daughter board) and are connected to the bus using expansion connectors, also called expansion slots (English slot - slot, groove).
2.3. Basic computer blocks
Any computer, as a rule, includes three main nodes (blocks):
system unit;
Monitor (display) for displaying information;
Description of the presentation by individual slides:
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Internal memory is an electronic device that stores information while it is powered by electricity. When the computer is disconnected from the network, information from RAM disappears. The program is stored in the internal memory of the computer during its execution. (Von Neumann principle - stored program principle). External memory consists of various magnetic media (tapes, disks), optical disks. Storing information on them does not require constant power supply. The figure shows a diagram of a computer structure taking into account two types of memory. Arrows indicate directions of information exchange
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1. Devices included in the system unit 1.1. Motherboard The motherboard provides communication between all PC devices by transmitting signals from one device to another. On the surface of the motherboard there is a large number of connectors designed for installing other devices: sockets - sockets for processors; slots – connectors for RAM and expansion cards; I/O port controllers. The motherboard is a printed circuit board on which most components of a computer system are mounted. The name comes from the English motherboard, sometimes the abbreviation MB or the word mainboard is used - main board.
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A – connector (socket) of the central processor B – connectors for RAM C – connectors for connecting a video card, internal modem, etc. D – connectors for connecting external input/output devices 1. Devices included in the system unit 1.1. Motherboard Match the connectors indicated in the figure (devices for switching) and their purpose:
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The processor has a large radiator cooled by a fan (cooler). Structurally, the processor consists of cells in which data can not only be stored, but also changed. The internal cells of the processor are called registers. Devices included in the system unit 1.2. Central processor The central processing unit, or central processing unit (CPU), is the main computer chip in which all calculations are performed.
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Address bus. Intel Pentium processors (namely, they are the most common in personal computers today) have a 32-bit address bus, that is, it consists of 32 parallel lines. Data bus. This bus copies data from RAM to processor registers and back. In computers built on Intel Pentium processors, 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. In order for the processor to process data, it needs instructions. It must know what to do with the bytes stored in its registers. These commands also come to the processor from RAM, but not from those areas where data arrays are stored, but from where programs are stored. Commands are also represented in bytes. The simplest commands fit into one byte, but there are also those that require two, three or more bytes. Devices included in the system unit 1.2. Central Processing Unit The processor is connected to the rest of the computer devices, and primarily to the RAM, by several groups of conductors called buses. There are three main buses: data bus, address bus and command bus.
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The operating voltage of the processor is provided by the motherboard, so different brands of processors correspond to different motherboards (they must be selected together). Early processor models had an operating voltage of 5V, but today it is less than 3V. The processor capacity shows how many bits of data it can receive and process in its registers at a time (in one clock cycle). The first processors were 4-bit. The processor is based on the same clock principle as in a regular watch. The execution of each command takes a certain number of clock cycles. In a personal computer, clock pulses are set by one of the microcircuits included in the microprocessor kit (chipset) located on the motherboard. The higher the clock frequency entering the processor, the more commands it can execute per unit time, the higher the processor performance. Data exchange within the processor occurs several times faster than exchange with other devices, such as RAM. In order to reduce the number of accesses to RAM, a buffer area is created inside the processor - the so-called cache memory. It's like "super RAM". 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 of the Devices included in the system unit 1.2. Central processor The main parameters of processors are: operating voltage, bit depth, operating clock frequency, internal clock frequency multiplication factor and cache memory size.
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There are two types of RAM - random access memory (RAM - Random Access Memory) and read-only memory (ROM - Read Only Memory). Random access memory (RAM) is used to store programs, data, and intermediate results of calculations while the computer is running. Data can be selected from memory in a random order, rather than strictly sequentially, as is the case, for example, when working with magnetic tape. Devices included in the system unit 1.3. Random access memory Random access memory (RAM - random access memory). Read-only memory (ROM) is used to permanently house certain programs, for example, the computer boot program - BIOS (basic input-output system). The contents of this memory cannot be changed while the computer is running. RAM is volatile, i.e. data is stored in it only until the PC is turned off.
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Unlike a “floppy” disk (floppy disk), information in a hard disk drive is recorded on hard (aluminum or glass) plates coated with a layer of ferromagnetic material. In operating mode, the read heads do not touch the surface of the plates due to the layer of air formed during the rapid rotation of the disks. Devices included in the system unit 1.4. Hard drive Hard disk drive, hard drive or hard drive (English Hard Disk Drive, HDD) - a non-volatile, rewritable computer storage device
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The hard drive received the name “Winchester” thanks to IBM, which in 1973 released the hard drive model 3340, which for the first time combined disks and read heads in one one-piece housing. When developing it, engineers used the short internal name “30-30”, which meant two modules (in the maximum configuration) of 30 MB each. Kenneth Haughton, the project manager, in consonance with the designation of the popular hunting rifle “Winchester 30-30”, proposed calling this disc a “Winchester”. In Europe and America, the name "Winchester" fell out of use in the 1990s; in Russian computer slang, the name “hard drive” has been preserved, shortened to the word “screw”. Devices included in the system unit 1.4. HDD
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Interface is a method used to transfer data. Modern drives can use ATA (IDE, EIDE), Serial ATA, SCSI, SAS, FireWire, USB and Fiber Channel interfaces. Capacity is the amount of data that can be stored by the drive. The capacity of modern devices can reach up to 1.5 TB; hard drives with a capacity of 80, 120, 200, 320 GB are common in PCs today. In contrast to the system of prefixes adopted in computer science, denoting a multiple of 1024 values (kilo = 1024), manufacturers use multiples of 1000 values when designating the capacity of hard drives. So, for example, the “real” capacity of a hard drive labeled “200 GB” is 186.2 GB. Physical size - Almost all modern drives for personal computers and servers are either 3.5 or 2.5 inches in size. The latter are more often used in laptops. Spindle speed is the number of spindle revolutions per minute. Access time and data transfer speed largely depend on this parameter. Currently, hard drives are produced with the following standard rotation speeds: 4200, 5400 and 7200 (laptops), 7200 and 10000 (personal computers), 10000 and 15000 rpm. (servers and high-performance workstations). Devices included in the system unit 1.4. Hard drive Specifications
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Usually a video card is an expansion card and is inserted into a special slot (ISA, VLB, PCI, AGP, PCI-Express) for video cards on the motherboard, but it can also be built-in. A modern graphics card consists of the following main parts: Graphics processing unit (GPU) - deals with calculations of the output image, relieving the central processor of this responsibility, and makes calculations for processing 3D graphics commands. A graphics card (also known as a graphics card, video card, video adapter) is a device that converts an image stored in the computer's memory into a video signal for the monitor. Devices included in the system unit 1.5. Graphics card Video controller - responsible for generating images in video memory. Video memory - acts as a buffer in which an image is stored in digital format for display on a monitor screen. Digital-to-analog converter (DAC) - used to convert the image generated by the video controller into color intensity levels supplied to an analog monitor
Slide 13
Slide description:
On the motherboard, the sound card is installed in the ISA (legacy format) or PCI (modern format) slots. When the sound card is installed, ports appear on the back panel of the computer case for connecting speakers, headphones, and a microphone. Devices included in the 1.6 system unit. Sound card A sound card (also called a sound card, audio adapter) is used to record and play back various sound signals: speech, music, sound effects. 1.7. Network card A network card (also known as a network card, network adapter, Ethernet card, NIC (English network interface card)) is a printed circuit board that allows computers to communicate with each other via a local network. Typically, the network card comes as a separate device and is inserted into the expansion slots of the motherboard (mainly PCI, early models used the ISA bus).
14 slide
Slide description:
Typically, a floppy disk is a flexible plastic plate coated with a ferromagnetic layer, hence the English name “floppy disk”. This plate is placed in a protective shell that protects the magnetic layer from physical damage. The shell can be flexible or durable. Floppy disks are written and read using a special device - a floppy drive. Floppy disks typically have a write-protect feature that allows read-only access to the data. Devices included in the system unit 1.8. 3.5'' floppy disk is a portable magnetic storage medium used for repeated recording and storage of relatively small data. The first floppy disk with a diameter of 200 mm (8″) and a capacity of 80 kilobytes was introduced by IBM in 1971. In 1981, Sony released A floppy disk with a diameter of 3½" (90 mm) was introduced to the market. Its later version has a capacity of 1440 kilobytes or 1.40 megabytes. It was this type of floppy disk that became the standard and is still used today.
15 slide
Slide description:
Devices included in the system unit 1.9. Compact Disc Storage Digital information is represented on a CD by alternating dimples (non-reflective spots) and light-reflecting islands. A CD has just one physical track in the shape of a continuous spiral running from the outer diameter of the disc to the inner diameter. Reading information from a CD occurs using a laser beam, which, falling on a reflective island, is deflected to a photodetector, which interprets this as a binary unit. The laser beam entering the cavity is scattered and absorbed: the photodetector records a binary zero. The data transfer rate for the drive is determined by the rotation speed of the disk. It is usually indicated in comparison with the Audio CD standard, for which the data reading speed is about 150 KB/s. Those. CDx2 means that the data exchange speed with such a disk is twice as high as 150 KB/s. The maximum rotation speed of a CD disc is 52 times higher than the reading speed of an Audio CD. 52x150 KB/s=7800 KB/s. Currently, drives with the ability to write once (CD-R) and rewrite (CD-RW) information have become available to the mass user.
16 slide
Slide description:
Devices included in the system unit 1.10. DVD drives DVD (Digital Versatile Disc, digital multi-purpose, or universal disk) are high-capacity optical discs that are used for storing full-length films, high-quality music, and computer programs. There are several DVD options that differ in capacity: single-sided and double-sided, single-layer and double-layer. Single-sided, single-layer DVDs have a capacity of 4.7 GB of information, double-layer - 8.5 GB; double-sided single-layer ones hold 9.4 GB, double-layer ones - 17 GB. The laser beam in a typical CD-ROM drive has a wavelength of 780 nm, while in DVD devices it ranges from 635 nm to 650 nm, making DVD recording density significantly higher. In addition to reading data from DVDs at speeds of about 1.2 MB/s, DVD drives can read regular CD-ROMs at speeds roughly equivalent to 8-10 speed CD-ROM drives.
18 slide
Slide description:
Any biological object (human, animal, insect) in the process of its life must adequately respond to influences from objects in the world around it. This is possible only if biological objects have organs that implement the necessary functions of working with information (data) (Fig. 18.1.).Functions of an object that implements data processing
Rice. 18.1.
Input (reception) of data (information0 from another object;
Data (information) storage;
Data (information) processing;
Output (transfer) of data (information) to another object.
18.1. Functions of a computer as a data processing system
Rice. 18.1.1.
In Figure 18.1.1. A diagram of the anti-lock braking system (AST) is presented. It is obvious that the management of any object is based on the peculiarities of the functioning of this control object. Control consists in the fact that the control object is transferred to various states using a control program installed on the computer. The purpose of ACT is to ensure that the car wheel always rotates. If the wheel is blocked, the vehicle will move uncontrollable by the steering wheel.
The driver presses the brake pedal when braking. The task of the AST is to prevent the wheel from locking.
The first function (input) is that the analog signals from the wheel rotation sensor are converted into digital signals (codes) and entered into the computer memory. The second function (storage) is that the wheel condition codes stored in memory are perceived by the control program. If the code corresponds to wheel rotation, the control system is silent. If the code corresponds to the “stationary” wheel state, the program generates a control code that is issued (output function) to the DAC. This code is converted by the DAC into voltage and perceived by the AST as a control action to “relax the braking force.” AST weakens the braking force and the wheel begins to rotate.
Analysis of this diagram shows that a computer can be considered as a data processing device, because This device implements all 4 functions. However, it should be noted that these functions are implemented using hardware and software. It is obvious that the actual task of controlling the electron microscope is implemented by the program. The equipment plays a supporting role. It is for this reason that they talk about hardware and software controls.
In Figure 18.1.2. a more complex hardware and software tool is presented.
Rice. 18.1.2.
In this electron microscope control circuit, a person is present in the control loop. Signals about the object under study are converted into codes and displayed on a display device. A person, looking at an image of an object, can control an electron microscope by issuing commands to it: enlarge the image (move the microscope lens closer to the object), reduce the image, move the lens to the right, etc. Human commands are converted by the program into control codes, which, in turn, are converted by the DAC into signals of various voltages. The signals are sensed by the electron microscope's controls, and the microscope executes user-specified commands.
Analysis of the two figures shows that a computer can function without a device such as a display. A display can be thought of as a display device as well as an output device. Human input of information is carried out using a keyboard.
Functional device of the computer: hardware that implements a specific computer function.
Backbone-modular principle of organization computer: all functional elements of the computer are connected to each other using a common (system) backbone (bus) and exchange data with each other through this functional device (Fig. 18.1.3.).
Composition of the system trunk:
data bus;
address bus;
control bus.
Rice. 18.1.3.
We have already looked at the process of program execution. The processor must contact the OP for the next instruction, then the processor must contact the OP to fetch the operands, and finally, the processor must contact the OP to record the result of the operation on the operands. If during program execution it is necessary to perform input or output operations, then only the program developer knows the moment when these operations begin. This means that the command system can contain not only arithmetic and logical commands, but also device control commands. Conclusion: the primary source of exchange between two devices is the processor, which executes the program command. The processor outputs to the address bus (ABA) the addresses of devices (subscribers) between which data exchange must occur. Subscribers must coordinate their actions using control signals via the control bus. Data, of course, must be transmitted over the data bus. In Figure 18.1.4. the functional structure of a computer is presented in a generalized form.
Rice. 18.1.4.
CPU: a functional device that executes program commands.
Computer memory: a functional device that provides storage of data presented in electronic form.
The processor does not have a storage function. For this reason, as previously discussed, the processor must constantly access memory. In each cycle, 1 word is exchanged between the processor and memory. Obviously, the memory must have the same operating speed (performance) as the processor. Technical elements have been found that have performance close to that of the processor. However, these elements have 2 drawbacks. The first drawback: the data stored in this memory is lost when the power is turned off. The second disadvantage relates to the economic sphere: these devices are quite expensive. Therefore, in modern computers there are 2 levels of memory. The first level is random access memory (RAM). It is only with it that the processor exchanges data during program execution.
The second level memory is a hard magnetic disk (HMD). This is a slow device. It exchanges data with the operating system and other functional elements of the computer. If you trace the development of personal computers, you can see a constant increase in the amount of RAM. This is also due to the economic factor: as production increases and element base production technologies develop, RAM modules become cheaper. Evolution of OP volumes: 128 KB, 256 KB, 512 KB, 1 MB, 128 MB, 256 MB, 512 MB, 1 GB, 2 GB, etc.
In each cycle, the OP exchanges 1 word with the processor. In each cycle, the OP exchanges a block consisting of several words with the LMD (Fig. 18.1.5.).
Computer core: a set of functional devices that implement storage and processing functions. The computer core includes: processor, RAM, and hard disk drive.
Rice. 18.1.5.
Note. Please note that the concept of “computer core” is functional, not technical (formal). An example of a formal approach is the division of memory into internal and external. Internal memory is considered to be RAM, and external memory is considered to be long-term memory. The criterion for this separation is the formal ability of memory devices to store information after the power is turned off. At the same time, this classification does not explain the concepts of “internal” and “external”. What is the object in relation to which these concepts are used?
Advice. When introducing any classification, it is necessary to clearly define the classification criterion and all the concepts used in describing the classification.
The remaining devices are input/output devices in relation to the kernel.
Keyboard is the simplest input device in a personal computer.
A printer: device for outputting data to paper.
For the convenience of the user, a graphical manipulator and display are included in the personal computer.
Graphic manipulator: a functional device that allows the graphical pointer to move across the display screen and issue a signal to the program to execute the command indicated by the graphical pointer.
Structural implementations of a graphical manipulator: mouse, trackball, touch pad.
Graphic index: an icon with which the user defines for programs an object on which a user-specified operation is to be performed.
Display: a functional device of a computer that provides visual display of information on the screen that allows the user to effectively use the computer's capabilities.
As you can see, the graphical pointer and display do not perform any of the 4 functions of the data processing device.
Floppy disk drive: an input/output device for exchanging data with an external storage medium based on a floppy disk (floppy disk).
Drive unitCD-disk: I/O device for exchanging data with an external CD-based storage medium.
Basic configuration of a personal computer: a minimum set of functional devices supplied to the buyer.
The basic set changes in accordance with the technological capabilities of manufacturers. Currently, the basic configuration includes: core, display, CD (DVD) drive. A floppy disk drive is no longer always included with the computer when it is sold.
Modem: I/O device for exchanging computer data with analog signal channels (converting analog signals into discrete ones and vice versa).
The backbone - modular principle of computer organization combines the functional and constructive aspects of computer organization.
Module: a functional element of a computer implemented in the form of a specific design.
For example, a processor is implemented on a microcircuit, which is structurally designed in the form of a parallelepiped with many contacts for electrical connection with other functional elements and is inserted into a connector. The CD drive, DVD drive, and hard magnetic disk are made in the form of parallelepiped boxes.
A computer, as a technical system, must include modules that implement auxiliary functions: cooling of various devices (forced), protecting people from radiation, connecting all modules in the form of a structure convenient for installation and transfer (assembly elements).
Each functional device can be implemented on different physical principles and have a different design. Assembling a computer is carried out by installing and securing modules in assembly elements. Computer repair is carried out at the level of module replacement.
Assembly elements of a personal computer: system unit, motherboard, display case, modem case.
18.2. Functional Device Controller Purpose
In modern personal computers, each functional device of the computer is connected to the system bus (Fig. 18.2.1.).
Rice. 18.2.1.
In order to be able to control a functional device, issue commands to it, receive information from it about the results of command execution, and, if necessary, issue data to it or receive data from it, signals, both control and information, must be exchanged between it and the system backbone. Naturally, the exchange of these signals must occur according to certain rules.
Interface: rules for interaction between hardware or software.
Due to the increasing demand for computers, new development companies have emerged. The result of their work was the emergence of computer platforms and families of computers with different interfaces on system backbones. At the same time, manufacturers of functional devices find themselves in a difficult situation. They had to produce different industrial products with the same functions. To reduce production costs, the following solution was found. The functional device is divided into 2 parts (Fig. 18.2.2.). The first part has all the necessary functions and has a basic permanent interface. This part is the most complex and, as a rule, determines the cost of the entire functional device. The second part, called controller, provides only coordination of the basic hardware interface of the functional device with the system bus interface of a specific computer platform.
Thus, a manufacturer can produce one complex product and several simple ones, which ensure the use of one complex device in computers with different system bus interfaces.
Rice. 18.2.2.
This idea was developed in relation to displays (Fig. 18.2.3.). Controller - video adapter (video controller) is such a complex product that it is produced by third manufacturers, but its interface with displays is standardized. For this reason, display manufacturers do not produce video controllers.
Federal Agency for Education
State educational
institution of higher professional education
"Tomsk Polytechnic University"
Faculty of AVT
Department of VT
“CURRENT STATE, STRUCTURAL AND FUNCTIONAL ORGANIZATION AND PROSPECTS FOR THE DEVELOPMENT OF DESKTOP PCS.”
Introduction………………………………………………………………………………..3
I. Functional and structural organization of PC……………………………4
II. The current state of desktop PCs……………………………..14
III. Prospects for the development of desktop PCs……………………………...16
Conclusion……………………………………………………………...19
References………………………………………………………..20
Introduction
Nowadays, when computer technology is developing at a rapid pace, many new architectures, “varieties” of computers have appeared, and whether a device belongs to one or another variety determines its purpose and the tasks assigned to it.
In recent years, desktop personal computers (PCs) have become widespread. Strictly speaking, a computer is a set of technical and software tools designed for automatic information processing in the process of solving computational and information problems. Computer architecture refers to the general functional and structural organization of the machine, which determines data encoding methods, composition, purpose, and principles of interaction between hardware and software. For any computer, including a desktop PC, the following important architectural components can be distinguished:
1. Functional and logical capabilities of the processor (command system, command and data formats, addressing methods, bit depth of processed words, etc.)
2. Structural organization and principles of hardware management (central processor, memory, input/output, system interface, etc.)
3. Software (operating system, programming language translators, application software)
In this essay I will consider the structure and further development possibilities of desktop computers.
The advantages of a PC are:
- 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 everyday life;
- the “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 5 thousand hours between failures).
I . Structural and functional organization of PC
Let's consider the composition and purpose of the main PC blocks:
Block diagram of a personal computer
Microprocessor (MP). This is a central PC unit designed to control the operation of all machine blocks and to perform arithmetic and logical operations on information.
The microprocessor includes:
- control device (UU)- generates and supplies to all units of the machine at the right times certain control signals (control pulses), determined by the specifics of the operation being performed and the results of previous operations; generates addresses of memory cells used by the operation being performed and transmits these addresses to the corresponding computer blocks; the control device receives a reference sequence of pulses from the clock pulse generator;
- arithmetic logic unit (ALU)- designed to perform all arithmetic and logical operations on numerical and symbolic information (in some PC models, an additional ALU is connected to the ALU to speed up the execution of operations math coprocessor);
- microprocessor memory (MPP)- serves for short-term storage, recording and output of information directly used in calculations in the next cycles of machine operation. MPP is built on registers and is used to ensure high speed of the machine, because the main memory (RAM) does not always provide the speed of writing, searching and reading information necessary for the efficient operation of a high-speed microprocessor. Registers- high-speed memory cells of various lengths (in contrast to OP cells, which have a standard length of 1 byte and lower speed);
- microprocessor interface system- implements pairing and communication with other PC devices; includes an internal MP interface, buffer storage registers and control circuits for input/output ports (I/O) and the system bus. Interface(interface) - a set of means for pairing and communicating computer devices, ensuring their effective interaction. I/O port (I/O ≈ Input/Output port)- interface equipment that allows you to connect another PC device to the microprocessor.
Clock generator. It generates a sequence of electrical impulses; the frequency of the generated pulses determines the clock frequency of the machine. The time interval between adjacent pulses determines the time of one cycle of machine operation or simply machine operation cycle .
The frequency of the clock pulse generator is one of the main characteristics of a personal computer and largely determines the speed of its operation, because each operation in the machine is performed in a certain number of clock cycles.
System bus. This is the main interface system of a computer, ensuring the pairing and communication of all its devices with each other.
The system bus includes:
- code data bus(KSD), containing wires and interfacing circuits for parallel transmission of all bits of the numeric code (machine word) of the operand;
- address code bus(KSA), including wires and interface circuits for parallel transmission of all bits of the address code of a main memory cell or an input/output port of an external device;
- instruction code bus(KShI), containing wires and interface circuits for transmitting instructions (control signals, pulses) to all blocks of the machine;
- power bus, having wires and interface circuits for connecting PC units to the power supply system.
The system bus provides three directions of information transfer:
1) between the microprocessor and main memory;
2) between the microprocessor and the input/output ports of external devices;
3) between the main memory and the I/O ports of external devices (in direct memory access mode).
All blocks, or rather their I/O ports, are connected to the bus in the same way through the corresponding unified connectors (joints): directly or through controllers (adapters). The system bus is controlled by the microprocessor either directly or, more often, through an additional chip - bus controller, generating the main control signals. Information exchange between external devices and the system bus is carried out using ASCII codes.
Main memory (RAM). It is designed for storing and promptly exchanging information with other units of the machine. The OP contains two types of storage devices: read-only memory (ROM) and random access memory (RAM).
ROM serves to store unchangeable (permanent) program and reference information; it allows you to quickly only read the information stored in it (the information in the ROM cannot be changed).
RAM designed for online recording, storage and reading of information (programs and data) directly involved in the information and computing process performed by a PC in the current period of time. The main advantages of RAM are its high speed and the ability to access each memory cell separately (direct address access to the cell). As a disadvantage of RAM, it should be noted that it is impossible to store information in it after turning off the machine's power (volatility dependence).
External memory. It refers to external devices of the PC and is used for long-term storage of any information that may ever be required to solve problems. In particular, all computer software is stored in external memory. External memory contains various types of storage devices, but the most common, available on almost any computer, are hard disk drives (HDD) and floppy disk drives (FLMD).
The purpose of these drives is to store large amounts of information, record and release stored information upon request into a random access memory device. Hard disk drives and flat disk drives differ only in design, the volume of stored information and the time it takes to search, record and read information.
Storage devices on cassette magnetic tape (streamers), optical disk drives (CD-ROM - Compact Disk Read Only Memory - CD with read-only memory), etc. are also used as external memory devices.
Power supply. This is a block containing autonomous and network power supply systems for a PC.
Timer. This is an in-machine electronic clock that provides, if necessary, automatic recording of the current moment in time (year, month, hours, minutes, seconds and fractions of seconds). The timer is connected to an autonomous power source - a battery and continues to work when the machine is disconnected from the network.
External devices (ED). This is the most important component of any computing complex. Suffice it to say that in terms of cost, VCs sometimes account for 50–80% of the total PC. The composition and characteristics of the VC largely depend on the possibility and effectiveness of using PCs in control systems and in the national economy as a whole.
PC control units ensure the interaction of the machine with the environment; users, control objects and other computers. VEs are very diverse and can be classified according to a number of characteristics. Thus, according to their intended purpose, the following types of devices can be distinguished:
- external storage devices (ESD) or external PC memory;
- user dialog tools;
- information input devices;
- information output devices;
- means of communication and telecommunications.
Dialogue tools user devices include video monitors (displays), less often remote control typewriters (printers with keyboards) and speech input/output devices.
Video monitor (display) - a device for displaying information input and output from a PC.
Voice input/output devices belong to the fast-growing media. Speech input devices are various microphone acoustic systems, “sound mice”, for example, with complex software that allows them to recognize letters and words spoken by a person, identify them and encode them.
Speech output devices are various sound synthesizers that convert digital codes into letters and words that are reproduced through loudspeakers (speakers) or speakers connected to a computer.
To information input devices relate:
- keyboard- a device for manually entering numerical, text and control information into a PC;
- graphics tablets (digitizers)- for manually entering graphic information and images by moving a special pointer (pen) across the tablet; when you move the pen, the coordinates of its location are automatically read and these coordinates are entered into the PC;
- scanners(reading machines) - for automatic reading from paper media and entering typewritten texts, graphs, pictures, drawings into a PC; in the scanner encoding device in text mode, read characters, after comparison with reference contours by special programs, are converted into ASCII codes, and in graphic mode, read graphs and drawings are converted into sequences of two-dimensional coordinates;
- manipulators(pointing devices): joystick - lever arm, mouse, trackball - ball in a frame, light pen etc. - to enter graphic information on the display screen by controlling the movement of the cursor across the screen, followed by encoding the cursor coordinates and entering them into the PC;
- touch screens- for entering individual image elements, programs or commands from a split-screen display into a PC.
- TO information output devices relate:
- printers- printing devices for recording information on paper;
- plotters (plotters)- to output graphic information (graphs, drawings, drawings) from a PC onto paper; There are vector plotters with drawing images using a pen and raster plotters: thermographic, electrostatic, inkjet and laser. By design, plotters are divided into flatbed and drum plotters. The main characteristics of all plotters are approximately the same: plotting speed - 100 - 1000 mm/s, the best models have color images and halftone transmission; Laser plotters have the highest resolution and image clarity, but they are the most expensive.
Devices communications and telecommunications are used for communication with devices and other automation equipment (interface adapters, adapters, digital-to-analog and analog-to-digital converters, etc.) and for connecting PCs to communication channels, to other computers and computer networks (network interface cards, "joints" ", data transmission multiplexers, modems).
Many of the devices mentioned above belong to a conditionally selected group - multimedia.
Multimedia(multimedia - multimedia) is a set of hardware and software that allows a person to communicate with a computer using a variety of natural media: sound, video, graphics, texts, animation, etc.
Multimedia means include speech input and output devices; scanners that are already widespread (since they allow printed texts and drawings to be automatically entered into a computer); high-quality video (video-) and sound (sound-) cards, video capture cards (videograbber), which capture images from a VCR or video camera and enter it into a PC; high-quality acoustic and video reproduction systems with amplifiers, sound speakers, large video screens. But, perhaps, with even greater reason, multimedia includes external large-capacity storage devices, often used to record audio and video information.
Nowadays, CDs, DVDs, as well as flash drives, which have become widespread recently, are used to record, store and reproduce information. Ease of use, minimal dimensions, increasing memory capacity and decreasing price put the latter beyond competition, and it is quite possible that in the future this will lead to the displacement of optical disks from the market, since previously CDs replaced floppy disks.
Additional schemes. To the system bus and to the PC MP along with typical external devices can be connected and some additional boards with integrated circuits that expand and improve the functionality of the microprocessor: mathematical coprocessor, direct memory access controller, input/output coprocessor, interrupt controller, etc.
Math coprocessor widely used for accelerated execution of operations on binary floating-point numbers, on binary-coded decimal numbers, and for calculating some transcendental, including trigonometric, functions. The mathematical coprocessor has its own command system and works in parallel (shared in time) with the main MP, but under the control of the latter. Operations are accelerated tenfold. The latest MP models, starting with the MP 80486 DX, include a coprocessor in their structure.
Direct Memory Access Controller frees the MP from direct control of magnetic disk drives, which significantly increases the effective performance of the PC. Without this controller, data exchange between the VSD and RAM is carried out through the MP register, and if it is present, data is directly transferred between the VSD and RAM, bypassing the MP.
I/O coprocessor due to parallel work with the MP, it significantly speeds up the execution of I/O procedures when servicing several external devices (display, printer, HDD, HDD, etc.); frees the MP from processing I/O procedures, including implementing the direct memory access mode.
The interrupt controller plays a vital role in a PC.
Interrupt- temporary stop of the execution of one program for the purpose of prompt execution of another, currently more important (priority) program.
Interruptions occur constantly when the computer is running. Suffice it to say that all information input/output procedures are performed using interrupts, for example, timer interrupts occur and are serviced by the interrupt controller 18 times per second (naturally, the user does not notice them).
Interrupt controller serves interrupt procedures, receives an interrupt request from external devices, determines the priority level of this request and issues an interrupt signal to the MP. The MP, having received this signal, suspends the execution of the current program and proceeds to execute a special program for servicing the interrupt that the external device requested. After completion of the maintenance program, the interrupted program is resumed. The interrupt controller is programmable.
PC design elements
Structurally, PCs are made in the form of a central system unit, to which external devices are connected via connectors: additional memory devices, keyboard, display, printer, etc.
System unit typically includes the system board, power supply, disk drives, accessory connectors, and expansion boards with controllers - adapters of external devices.
On system board(often called motherboard Mother Board), as a rule, are located:
- microprocessor;
- mathematical coprocessor;
- clock generator;
- RAM and ROM blocks (chips);
- keyboard adapters, HDD and HDD;
- interrupt controller;
- timer, etc.
PC Functional Specifications
The main characteristics of the PC are:
1. Speed, performance, clock speed.
Performance units serve:
- MIPS (MIPS - Mega Instruction Per Second) - a million operations on numbers with a fixed point (dot);
- MFLOPS (Mega FLoating Operations Per Second) - a million operations on floating point (dot) numbers;
- KOPS (KOPS - Kilo Operations Per Second) for low-performance computers - a thousand certain averaged operations on numbers;
- GFLOPS (Giga FLoating Operations Per Second) - billion operations per second on floating point numbers (dot).
Evaluation of computer performance is always approximate, because in this case they are guided by some average or, conversely, specific types of operations. In reality, different sets of operations are used to solve different problems. Therefore, to characterize a PC, instead of performance, they usually indicate the clock frequency, which more objectively determines the speed of the machine, since each operation requires a very specific number of clock cycles to complete. Knowing the clock frequency, you can quite accurately determine the execution time of any machine operation.
2. Bit capacity of the machine and interface code buses.
Bit depth≈ this is the maximum number of bits of a binary number on which a machine operation can be simultaneously performed, including the operation of transmitting information; The greater the bit depth, the greater, other things being equal, will be the performance of the PC.
3. Types of system and local interfaces.
Different types of interfaces provide different speeds of information transfer between machine nodes, allow you to connect a different number of external devices and their different types.
4. RAM capacity.
RAM capacity is most often measured in megabytes (MB), less often in kilobytes (KB). 1 MB = 1024 KB = 1024 2 bytes.
Many modern application programs with RAM capacity of less than 8 MB simply do not work or work, but very slowly.
It should be borne in mind that increasing the capacity of the main memory by 2 times, among other things, increases the effective performance of the computer when solving complex problems by approximately 1.7 times.
5. Capacity of the hard disk drive (hard drive). Hard drive capacity is usually measured in megabytes or gigabytes (1 GB = 1024 MB).
According to experts, many software products in 1997 will require up to 1 GB of external memory to operate.
6. Type And capacity of floppy disk drives.
Nowadays, floppy disk drives are mainly used, using floppy disks with a diameter of 3.5 and 5.25 inches (1 inch = 25.4 mm). The former have a standard capacity of 1.44 MB, the latter - 1.2 MB.
7. Types and capacity of cache memory.
Cache memory is a buffer, non-user-accessible, high-speed memory that is automatically used by the computer to speed up operations with information stored in slower storage devices. For example, to speed up operations with the main memory, a register cache memory is organized inside the microprocessor (first-level cache memory) or outside the microprocessor on the motherboard (second-level cache memory); To speed up operations with disk memory, cache memory is organized on electronic memory cells.
Keep in mind that the presence of a 256 KB cache memory increases PC performance by approximately 20%.
8. Type of video monitor (display) and video adapter.
9.Printer type.
10.Availability of a mathematical coprocessor.
The mathematical coprocessor allows you to speed up operations on binary floating point numbers and binary-coded decimal numbers by tens of times.
11. Available software and operating system type
12. Hardware and software compatibility with other types of computers.
Hardware and software compatibility with other types of computers means the ability to use on a computer, respectively, the same technical elements and software as on other types of machines.
13. Ability to work on a computer network
14. Ability to work in multitasking mode.
Multitasking mode allows you to perform calculations simultaneously on several programs (multi-program mode) or for several users (multi-user mode). Combining the operation time of several machine devices, possible in this mode, can significantly increase the effective speed of the computer.
15. Reliability.
Reliability is the ability of a system to perform fully and correctly all its assigned functions. PC reliability is usually measured by mean time between failures.
16. Price.
17. Dimensions and weight.
II . The State of the Desktop PC
At the current stage of PC development, two main platforms can be distinguished: Wintel and Apple.
The most common is the Wintel platform based on x86 processors due to its versatility and cost. This platform has many clones, i.e. similar computers produced by various companies in the USA, Western Europe, Russia, Japan, etc.
The Apple platform is represented by Macintosh computers, which are quite popular in the West. They occupy a rather narrow, but fairly stable niche in the world market.
The formal differences between platforms are the type of processor and operating system. The Macintosh uses a RISC processor architecture and a UNIX-like operating system kernel. However, in recent years, in terms of hardware, these two platforms are gradually moving closer together. Therefore, the main difference can be considered the amount of hardware and software produced in the world, where Wintel is beyond competition. Apple has a small number of high-end models, and is also significantly inferior in the amount of software produced. From this it follows that with a Wintel computer, you can perform any operation, but not always quickly and conveniently. On Apple, the same operation can be done either quickly or not at all.
Here are some examples of PC models that are popular today:
· Hacker Ph945
The platform is built on the basis of the ASUS M4A78, a high-quality mid-level motherboard based on the AMD 770 chipset with DDR2 support. It is well equipped, but without any frills. Among the practical features, we note the presence of an optical S/PDIF and an eSATA port on the rear panel. The system uses the recently announced quad-core AMD Phenom II X4 945 processor with decent processing power and 4 GB of RAM. The video subsystem is also up to par. GeForce GTS 250 graphics adapters are suitable for optimal PCs; with a very good price/performance ratio, they are able to provide a comfortable number of frames per second in the latest games.
The Phenom II X4 945 + GeForce GTS 250 combination generally performed very well during testing. Probably, in this combination there is a slight bias towards a slightly more powerful processor, but its capabilities will be useful in non-gaming multi-threaded tasks.
The system is assembled in a Microlab M4812 housing. This model is quite interesting in appearance and practical to use. On the front panel, in the compartment for 3.5-inch devices, there is a multi-format card reader Samsung SFD-321F/T4XB, which allows you to work with flash cards of all common types. Here, on the front side, there is an analog speed controller for the 120 mm fan mounted on the rear wall of the case. The power supply capabilities are quite sufficient for the proposed configuration to work, but without much reserve. The M-ATX-420W model complies with the ATX 1.3 standard, which does not imply heavy loads on the 12 V line used by modern video cards and CPU power systems. In the considered configuration, the computer's power consumption in idle mode is about 120 W, increasing to 270 W in “heavy” scenes in Crysis.
The system is not silent; in standby mode, the computer operates quite quietly; under load, the fans of the power supply and video card become more active, although in general the noise level is “below average.”
· Dell HPS 730 H2C
Dell has updated its line of XPS 730 H2C gaming computers. In a solid aluminum case, engineers placed a motherboard based on the NVIDIA nForce 790i Ultra SLI chipset with an installed Intel Core 2 Extreme processor (factory overclocked), a pair of ATI Radeon HD 3870 X2 or NVIDIA GeForce 8800GT SLI video cards and Corsair DOMINATOR DDR3 RAM. The H2C cooling system used in the PC is unique and is the result of a joint development by Dell, Intel, Delphi and CoolIT. 
The global desktop PC market is the largest, but in recent years has been experiencing an acute crisis due to a decline in demand for its products. Mobile PCs are becoming increasingly popular. This is due to the increase in the productivity of mobile computers and the simultaneous decrease in their prices.
III . Prospects for the development of desktop PCs
Due to the annual increase in the percentage of laptop sales, it may seem that mobile PCs may soon supplant desktop ones. However, experts believe that it is too early to write off desktop computers. Despite the increasing productivity of mobile PCs, the development of desktop computers is also not slowing down.
The popularity of laptops is primarily explained by their focus on solving those tasks that cannot be satisfied by a home computer (which, in turn, is associated with the possibility of autonomous power supply of laptops). However, it must be said that a desktop computer is primarily characterized by performance, which allows the user to perform almost any task on it. A mobile PC must have a number of additional characteristics (such as weight, dimensions, battery life), which relegates performance to the background. In addition, upgrading a laptop is difficult: it can be difficult to implement or simply impossible.
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| Comparative characteristics of laptops and desktop PCs |
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| Considering the factors of price, performance, upgrades, repairs and others, it should be recognized that to obtain a balanced and productive system, it is more practical to purchase a desktop PC. If mobility and all the accompanying factors are important, buying a laptop would be the best choice. The desktop system will not only allow you to solve highly complex problems, but will also provide the ability to scale to suit changing tasks. When predicting the foreseeable future of personal computers in terms of expanding their capabilities, it is necessary to note such areas as: · Increasing processor performance; · Miniaturization of processors; · Data entry using gestures and speech; · Increased hard drive capacity and recording density; · Reducing PC dimensions; · Introduction of nanotechnologies, biomolecular and quantum computing. Conclusion Further development of desktop personal computers in the above directions will undoubtedly ultimately lead to a change not only in their appearance, but also, quite possibly, in new computing algorithms and a new concept of the PC as a whole. There is also no doubt that over time, most users will switch to self-powered computers. But this will happen when mobile PCs have high enough characteristics to completely replace desktop computers. However, today's desktop PCs have many ways to go, and most manufacturers continue to improve them. Bibliography 1. Cheredov A.D. Organization of computers and systems: Textbook. – Tomsk: TPU, 2005. P. 3 – 30. 2. Murakhovsky V.I. PC hardware. New opportunities. – St. Petersburg: Peter, 2005. pp. 27 – 191. 3. Home PC: Online magazine. - http://www.dpk.com.ua/ 4. Computerra: Online magazine. – St. “PC (prospects and contours) of the future.” - http://offline.computerra.ru/2002/426/15178/ |
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Despite the enormous variety of computing technology and its unusually rapid improvement, the fundamental principles of machine design remain largely unchanged. In particular, starting from the very first generations, any personal computer consists of the following main devices: processor, memory (internal and external) and input and output devices. Let's take a closer look at the purpose of each of them.
The processor is the main device of the computer
The processor is the main device of the computer, in which all types of information are actually processed. Another important function of the processor is to ensure the coordinated action of all nodes that make up the computer. Accordingly, the most important parts of the processor are the arithmetic-logical unit ALU and the control unit CU.
Each processor is capable of executing a very specific set of universal instructions, most often called machine instructions. What exactly this set is is determined by the design of a particular processor, but it is not very large and is basically similar for different processors. The work of a personal computer consists of executing a sequence of such commands prepared in the form of a program. The processor is capable of organizing the reading of the next command, its analysis and execution, and also, if necessary, receiving data or sending the results of their processing to the required device. The processor itself must also choose which program instruction to execute next, and the result of this choice can often depend on the information currently being processed.
Although there are always special cells (registers) inside the processor for the operational storage of processed data and some service information, it deliberately does not provide space for program storage. Another device used in a computer for this important purpose is memory. Let's consider only the most important types of computer memory, since its range is constantly expanding and replenished with more and more new types.
Memory in general is designed to store both data and programs for processing it: according to the fundamental von Neumann principle, a single device is used for both types of information.
Computer memory
Starting from the very first personal computers, memory was immediately divided into internal and external. Historically, this has really been associated with placement inside or outside the processor cabinet. However, as the size of the machines decreased, an increasing number of devices could be placed inside the main processor case, and the original direct meaning of this division was gradually lost. However, the terminology has been preserved.
Inner memory
The internal memory of a modern computer is usually understood as high-speed electronic memory located on its motherboard. Now such memory is manufactured on the basis of the most modern semiconductor technologies (previously, magnetic devices based on ferrite cores were used - further evidence that specific physical principles do not matter). The most essential part of the internal memory is called RAM - random access memory. Its main purpose is to store data and programs for currently being solved problems. Probably every user knows that when the power is turned off, the contents of the RAM are completely lost. In addition to RAM, the internal memory of a modern computer also includes some other types of memory. Here we will only mention read-only memory (ROM), which, in particular, stores the information necessary to initially boot the computer when the power is turned on. As is obvious from the name, the information in ROM does not depend on the state of the computer (for a better understanding, you can point out some analogy between the information in ROM and “innate” unconditioned reflexes in living beings). Previously, the contents of the ROM were formed once and for all at the factory, but now modern technologies make it possible, if necessary, to update it without even removing it from the computer board.
External memory
External memory is implemented in the form of quite a variety of information storage devices and is usually designed in the form of independent blocks. This, first of all, should include drives on floppy and hard magnetic disks (users often call the latter somewhat jargonously hard drives), as well as optical drives (devices for working with CD ROMs). External memory devices have mechanically moving parts and therefore operate at significantly lower speeds than all-electronic internal memory. However, external memory allows you to store huge amounts of information for later use. We emphasize that information in external memory is, first of all, intended for the computer itself and is therefore stored in a form convenient for it; a person without the use of a machine is unable, for example, to even remotely imagine the contents of an unlabeled floppy disk or CD ROM.
Modern software systems are able to combine internal and external memory into a single whole, and so that the most rarely used information ends up in slower working external memory. This method makes it possible to very significantly expand the volume of information processed using a computer.
If the processor is supplemented with memory, then such a system can already be operational. Its significant disadvantage is the inability to find out anything about what is happening inside such a system. To obtain information about the results, it is necessary to supplement the computer with output devices that allow them to be presented in a form accessible to human perception. The most common output device is a display that can quickly and efficiently display both text and graphic information on its screen. In order to obtain a copy of the results on paper, a printing device, or printer, is used.
Input Devices
Finally, since the user often needs to enter new information into the computer system, input devices are also needed. The simplest input device is the keyboard. The widespread use of graphical interface programs contributed to the popularity of another input device - the mouse. Finally, a very effective modern device for automatically entering information into a computer is a scanner, which allows you not only to convert a picture from a sheet of paper into a graphic computer file, but also, using special software, to recognize text in the read image and save it in a form suitable for editing in a regular text editor.
Functional diagram of a modern computer
Now that we know the basic devices of a computer and their functions, it remains to find out how they interact with each other. To do this, let's turn to the functional diagram of a modern computer shown in the figure.
Picture 1
To connect the main computer devices with each other, a special information highway is used, usually called a bus by engineers. The tire consists of three parts:
address bus, on which the address of the required memory cell or device with which information will be exchanged is set;
a data bus through which the necessary information will actually be transmitted; and finally
a control bus that regulates this process (for example, one of the signals on this bus allows the computer to distinguish between the addresses of memory and input/output devices).
Let's take an example of how a processor reads the contents of a memory cell. Having made sure that the bus is currently free, the processor places the required address on the address bus and installs the necessary service information (operation - read, device - RAM, etc.) on the control bus. Now he can only wait for a response from RAM. The latter, “seeing” a request to read information addressed to it on the bus, extracts the contents of the required cell and places it on the data bus. We especially note that exchange on the bus, under certain conditions and in the presence of certain auxiliary equipment, can occur without the direct participation of the processor, for example, between an input device and internal memory.
We also emphasize that the functional organization of computers described by us in practice can be much more complicated. A modern computer may contain several coordinated processors, direct information channels between individual devices, several interacting highways, etc. However, if you understand the most general scheme, then it will be easier to understand a specific computer system. The backbone structure makes it easy to connect to the computer exactly those external devices that are needed for a given user. Thanks to it, it is possible to assemble any individual computer configuration from standard blocks.
Related information.
