Regulars of computer stores, regular readers of Chip, Home Computer and other magazines and newspapers specializing in computer topics can skip this paragraph. It is for those who are little familiar with computer hardware and believe that it is time to fill this gap in their education.
Computer(aka PC, computer) is a necessary and basic element of the implementation of any computer technology. To implement network technologies, you need to have several computers connected to a network. Consists of system unit, monitor, keyboard. When working with graphical operating systems, the technical tool necessary for work becomes mouse manipulator . The computer system unit is not a single indivisible device. Principle open architecture, implemented in modern PCs, allows, during the process of assembling a computer from individual standardized components, to achieve the desired technical characteristics (processor speed, amount of RAM and hard drive, video card performance, etc.). Thus, the PC contains the possibility of its further modernization, as well as connecting various peripheral devices to it that increase its capabilities. The set of devices connected to a computer depends on the need to solve certain problems and can be very diverse. The basis of the system unit is motherboard (or system) board , on which they are mounted CPU , memory chips, control systems (controllers) all PC devices. Internal modems, TV, FM tuners and other devices traditionally classified as peripheral devices can be mounted into the system unit in the form of separate boards, as well as in the form of separate blocks and devices drives for floppy disks and CDs, disk drives (hard drives) . The necessary components of the system unit are power supply and ventilation system , consisting of one or more fans.
PC Monitors are designed to visually display the results of computer operation. There are monitors with cathode ray tubes (CRT) and monitors with liquid crystal screens (TFT monitors). The latter have the following advantages compared to CRT monitors:
They do not emit harmful X-rays and do not create electromagnetic fields that interfere with the operation of electronic devices.
They almost completely use the working surface of the screen.
They typically have higher contrast and light output compared to CRT monitors.
They consume less electricity and are lighter in weight and dimensions.
Monitor performance depends largely on performance video cards computer and to create an optimal imaging system, the technical characteristics of both devices are important. Of the main technical characteristics of monitors, the most significant are considered screen size(diagonals), resolution(number of luminous dots - pixels, on the screen), frame rate.
External storage devices or devices for working with removable disks (floppy disks), compact disks (CD-ROM), optical disks (DVD-ROM), and other storage media are designed to create archives of files and transfer information from one computer to another. Can be used for disseminating information (electronic publications on CDs). In modern conditions, they are mandatory elements of the “standard” PC configuration.
Printers designed for printing documents on paper or other materials (for example, film). Distinguish matrix, inkjet and laser printers. The first allow you to organize the cheapest process for printing documents, although in many cases with insufficient quality. The latter are used for inexpensive color printing, including printing photographs and graphic images. Their relatively low cost makes inkjet printers the main device for printing documents at home. Laser printers for black-and-white printing are more expensive than inkjet ones, but they allow you to save money during operation due to the low cost of consumables (in terms of the number of pages printed per refill). These printers are most widely used in modern offices. Color laser printers are used in publishing houses, advertising agencies and other organizations, where significant initial investments in the purchase of these expensive devices pay off due to large volumes of color graphics printing.
Plotters– devices for large format printing. Used in the manufacture of posters, playbills, drawings, etc.
Scanners- devices for entering graphic information into a computer (scanning documents). They are used to transfer photographic materials obtained by traditional methods, handwritten texts and other documents from paper media to computer media.
Microphones, headphones, speaker systems– devices necessary for working with sound in multimedia programs. Can be used to record and playback audio information during meetings, presentations, watching videos, etc.
Web cameras– a device for recording video information into computer memory. Can be used for video conferencing, video telephony, as well as for holding public events.
Digital cameras– autonomous devices for obtaining photographic images on computer media. The use of graphic information display formats traditional for computer processing in digital cameras makes the joint use of digital cameras and a computer promising to create high-quality photographic materials.
TV, FM – tuners– devices that allow you to receive and play radio and television programs on devices connected to a computer.
Multimedia projectors– devices for projecting video information onto the screen, similar to the information displayed by the monitor. They are widely used for presentations, conferences, team meetings, exhibition activities, etc.
Purpose of devices important for organizing work on the network: modems, network cards, hubs, routers and bridges already discussed in the section on computer networks.
Uninterruptible power supplies– devices that allow you to maintain the functionality of computers during sudden power outages. Necessary to increase the reliability of both individual computers and computer networks as a whole.
You cannot embrace the immensity. MIDI keyboards, joysticks and a number of other devices were left outside the scope of our consideration. Anyone wishing to receive more information on this topic can be recommended to read the above-mentioned magazines and Internet pages reflecting news from the computer market.
To ensure maximum performance and correct operation, they use hardware and software that are very interconnected and clearly interact in different directions. Now let's touch on the consideration of hardware, since initially they occupy a dominant position in ensuring the functionality of any computer or even mobile system.
System hardware: general classification
So what are we dealing with? In fact, the complex hardware is familiar to everyone. In fact, many users call it computer hardware. Indeed, hardware is precisely the “hardware” and not the software components of any computer system. In the simplest version of the classification, they are divided into internal and external.
In addition, in this division we can distinguish three main and most meaningful classes of devices:
- input devices;
- output devices;
- information storage devices.
Naturally, it is worth noting separately the main elements of computer systems such as the motherboard, processor, etc., which are not included in any of the above classes and are basic elements without which no computer simply will work.
Basic Computer Elements
When describing the hardware of any computer, it is worth starting with the most important element - the motherboard, on which all the internal elements are located. And external devices are connected to it through the use of various types of connectors and slots.
Today there are quite a lot of varieties of “motherboards” and their manufacturers. True, such boards for desktop computers and laptops may differ in both shape and arrangement of individual elements. However, the essence of their use in computer systems does not change.
The second most important element is the central processor, which is responsible for performance. One of the main characteristics is the clock frequency, expressed in mega- or gigahertz, or, more simply, a value that determines how many elementary operations a processor can perform in one second. It is not difficult to guess that performance is nothing more than the ratio of the number of operations to the number of clock cycles that are necessary to perform (calculate) one elementary operation.
It is impossible to imagine computer hardware without RAM and hard drives, which are classified as storage devices. They will be discussed a little later.
Software and hardware
Modern computers also use hybrid devices, such as ROM or CMOS read-only memory, which is the basis of the basic input/output system called BIOS.
This is not only a “hardware” chip located on the motherboard. It has its own firmware, which allows not only to store immutable data, but also to test internal components even when the computer is turned on. Probably, many owners of stationary PCs have noticed that when they turn on, a signal from the system speaker is heard. This just indicates that the device check was successful.
Information input tools
Now let's look at input devices. At the moment, there are quite a lot of their varieties, and judging by the development of IT technologies, there will soon be even more of them. Nevertheless, the following are considered basic in this list:
- keyboard;
- mouse (trackpad for laptops);
- joystick;
- digital camera;
- microphone;
- external scanner.
Each of these devices allows you to enter a different type of information. For example, graphics are entered using a scanner, a video image is entered using a camera, text is entered on a keyboard, etc. However, both a mouse and a trackpad, in addition to everything else, are also controllers (manipulators).
As for the keyboard, the control functions in it are used through buttons or their combinations. At the same time, you can gain access to certain functions, parameters and commands of operating systems or other software.
Information output means
It is impossible to imagine hardware without output devices. The standard list contains the following:
- monitor;
- printer;
- plotter;
- sound and video system;
- multimedia projector.
The main one here is a computer monitor or laptop screen. It is clear that with modern methods of object-oriented programming, interaction with the user is carried out through a graphical interface, although this situation is equally applicable to systems in which commands are entered. In any case, the user should see what is displayed on the screen.
As for the remaining elements, they are desirable, although not required (well, except perhaps a graphics adapter, without which modern systems may not work).
Information storage means
Finally, one of the most important classes is information storage devices. Their presence, be it internal components or external media, is simply a must. The following varieties belong to this class:
- hard drive (hard drive);
- RAM;
- cache memory;
- external drives (floppy disks, USB devices).
Sometimes this also includes a BIOS system with CMOS memory, however, as mentioned above, these are rather hybrid devices that can be equally classified into different categories.
Of course, the main place here is occupied by hard drives and RAM. A hard drive is a hardware means of information (or rather, a means of storing it), because it is stored on it permanently, and in RAM - temporarily (when starting or operating programs, copying content to, etc.).
When you turn off the computer, the RAM is automatically cleared, but the information from the hard drive does not disappear. In principle, now removable media such as high-capacity USB devices also compete with the hard drive, but floppy disks and optical disks are becoming obsolete, if only because of their low capacity and the possibility of physical damage.
Communication devices
An optional class, although very popular in the modern world, can also be called devices responsible for ensuring communication both between individual computer terminals connected directly, and in networks (or even at the level of Internet access). Here are the main devices:
- network adapters;
- routers (modems, routers, etc.).
As is already clear, you cannot do without them when organizing networks (stationary or virtual) and providing access to the World Wide Web. But few people today know that two computers, for example, can be connected directly via cable, as was done twenty years ago. Of course, this looks somewhat impractical, however, you should not forget about this possibility, especially when you need to copy large amounts of information and there is no suitable medium at hand.
Security and data protection devices
Now about one more type of device. These are hardware protection devices, which include, for example, “iron” firewalls, also called firewalls (firewall in English - “fire wall”).
For some reason, today most users are accustomed to the idea that a firewall (also known as a firewall) is only a firewall. This is not the case. When organizing networks with a high level of security, the use of such components is not only desirable, but sometimes even simply necessary. Agree, the software part does not always cope with its functions and may not respond in time to interference in the network from the outside, not to mention access to what is stored on the hard drives of computers or servers.
Interaction of software and hardware
So, we briefly looked at the hardware. Now a few words about how they interact with software products.
Agree, operating systems, which provide user access to the computing capabilities of a PC, have their own requirements. Modern operating systems devour so many resources that they simply won’t work with outdated processors that lack computing power or lack the required amount of RAM. This, by the way, equally applies to modern application programs. And, of course, this is far from the only example of such interaction.
Conclusion
Finally, it is worth saying that the hardware of a modern computer was reviewed quite briefly, but conclusions can be drawn about the classification of the main elements of the system. In addition, it is worth noting that computer technology is developing, and this also leads to the fact that more and more external and internal devices of various types are appearing (take virtual helmets, for example). But as for the basic configuration, in this case the most important components are given, without which it is impossible for any computer system to exist today. However, for obvious reasons, mobile devices were not considered here, because their devices are somewhat different from computer terminals, although they have quite a lot in common.
Personal computer architecture is determined by a set of properties that are essential for the user and include the structure of the computer and its functionality, which can be divided into basic and additional. The main functions determine the purpose of the computer, i.e. processing, storing information and exchanging information with external objects. Additional functions increase the efficiency of performing basic functions: ensuring efficient operating modes, dialogue with the user, high reliability, etc. These functions are solved using the components of the personal computer architecture - hardware and software.
Computer structure- a certain model that establishes the composition, order and principles of interaction of its components.
The PC structure is central system unit, to which external devices are connected via connectors, a keyboard that allows you to enter characters into the computer, and a monitor for displaying text and graphic information.
The system unit consists of:
n system (motherboard) board on which it is located microprocessor(CISC - with a full set of instructions, RISC - with a reduced set of instructions, MISC - with a minimum set of instructions, Intel, AMD, Cyrix), designed to control the operation of all PC blocks and to perform arithmetic and logical operations. Microprocessors differ from each other by two characteristics: type (model) and clock frequency. The microprocessor includes:
control devices(supplies control pulses received from the clock pulse generator to all blocks, generates addresses of memory cells);
arithmetic-logical device, designed to perform all arithmetic and logical operations on numeric and symbolic information;
microprocessor memory, which is built on registers and ensures high PC performance, MP interface system for communication with other devices
math coprocessor, designed for accelerated execution of operations on floating point numbers;
n power supply;
n clock generator, which generates a sequence of electrical pulses, the frequency of which determines the clock frequency of the PC. Clock frequency is one of the main characteristics of a PC; it determines its operating speed, because each operation is performed in a certain number of cycles. Clock frequency, measured in megahertz (MHz), indicates how many elementary operations (cycles) the microprocessor performs in one second.
n system bus, which ensures the interfacing of all PC devices with each other and exchanges data between the MP and the OP, between the MP and the input-output system, between the OP and the input-output system.
n random access memory chips (RAM - memory and ROM - ROM - memory, register cache memory - ultra-random access memory, which is a buffer between the OP and the MP.
Structurally, the OP consists of millions of memory cells with a capacity of 1 byte each. The capacity of RAM is 2 orders of magnitude greater than the capacity of ROM.
n keyboard adapters, HDD and HDD
n power supply - a block containing autonomous and mains power systems
n interrupt controller, which temporarily stops the work of one program in order to promptly execute another (priority one).
n timer (in-machine electronic clock that provides automatic reading of machine time);
n floppy drive
n hard drive
n CD-ROM drive
n connectors for additional devices
n expansion cards with controllers - external device adapters
External (peripheral) devices:
n Storage devices
HDD hard drives
Flexible magnetic disks NGMD
CD-ROMs
Streamers
ZIP drives
Magneto-optical devices
n Input devices
Keyboard (special keyboard)
Manipulators (mouse, trackball, penmouse, infrared mouse)
graphics tablets (digitizers)
scanners (handheld, flatbed, drum, form scanners, bar scanners)
digital cameras
n Output devices
printers (matrix, laser, LED, inkjet)
video monitor (radiation: soft x-ray, ultraviolet, radio radiation, electrostatics; protective filters: mesh, film, glass)
plotter (plotters)
streamers
n Communications and telecommunications devices
Many of the devices listed are classified as means multimedia, representing a complex of hardware and software that allows you to communicate with a PC using a variety of environments that are natural for the user: sound, video, graphics, texts, animation, etc.
All devices that make up a modern computer are divided into two classes - central devices(primarily the processor and main memory) and external devices. Moreover, external devices are called not by their location, but by their functions. Central devices work with information presented in a specific form - in the form of binary numbers. The main purpose of external devices is to organize communication between central devices and the outside world, that is, to transform information from a form understandable to the user into an internal representation and vice versa. In addition, external devices are used for long-term storage of large amounts of information, for communication with other computers, etc.
All external devices can be divided into four groups.
Input devices : keyboard, hand controls (mouse), scanner, CD ROM, etc.
Output devices : video system, printer, plotter, etc.
Storage devices : external storage devices.
Communication and information transfer devices : modems, network cards (adapters), etc.
The general diagram of a computer complex based on a personal computer can be presented as follows (Fig. 1):
Rice. 1. General diagram of the computing complex
In Russia, the most widespread are the so-called IBM compatible personal computers.
1.2. Computer central devices
Rice. 2. Structure of the system (motherboard) board
Central Processing Unit – a software-controlled electronic digital device designed to process various information presented in digital form.
The main functions of the processor are:
Management of the entire computing complex.
Perform mathematical and logical operations with data.
Carrying out control functions, the processor ensures proper interaction of computer system components with each other. Control is carried out using pulse signals sent to the controlled components.
When performing calculations and logical operations, the processor is tuned to various operations and directly performs them.
IBM-compatible computers are equipped with microprocessors such as Intel or similar. Modern computers are equipped with Pentium microprocessors.
The most important parameter of a specific processor model is clock frequency, which is measured in frequency units (megahertz and gigahertz). This indicator determines the speed of the processor and, therefore, its performance. Typical clock speeds for some processors are shown in the table. It should be said that an increase in the serial number of the processor indicates an increase in its characteristics and, therefore, an improvement in the parameters of the computer as a whole.
Main memory– an electronic device designed to store information. Main memory consists of two parts: RAM and ROM. RAM is designed to store information necessary for the current work session. It provides both reading and writing of data. This memory is volatile, because its contents are destroyed when the power is turned off. Read-only memory provides read-only data. The contents of this part of the memory are permanent and can only be changed by special techniques. This non-volatile Memory and its contents are not lost in the absence of power.The most important characteristics of memory include its capacity (volume) and access time. Yocapacity memory is the number of addressable elements (cells) included in it. The amount of main memory of a computer is largely determined by the needs of the user and is set based on the capabilities of the user and the class of tasks he solves. It should be noted that a small amount of memory significantly slows down the completion of tasks, up to the complete impossibility of solving them. It is irrational to have too much memory, as it increases the price of the computer. For most general-purpose personal computers currently, the memory capacity is in the range of 32 MB256 MB. Access time is defined as the time interval between the moment a memory request occurs (for the purpose of reading or writing information) and the moment when the information is read or written. The typical value of this value for modern memory chips is 4*10 -8 s0.5*10 -8 s.
External Device Controllers They are software-controlled electronic units for matching (interfacing) external and central computer devices with each other. The need to use controllers is due to the fact that external devices usually cannot be directly connected to central ones. One reason for this is that the nature of the signals generated or perceived by the processor, as a rule, differs from the signals generated or perceived by the corresponding external device. The controller ensures coordination of these signals. In addition, since the controller is a software-controlled tool, with the appropriate software, the same controller can provide connection to a computer of different types of external devices. The use of controllers somewhat complicates the design of the computer, but at the same time it becomes possible to easily increase its technical capabilities.
System backbone(common bus) is used to transmit signals between elements of the system board. Monitoring the occupancy of the highway and controlling the passage of signals along it is carried out by the system highway control device. It does not allow access to the bus at those moments when it is already busy and “regulates” the flow of information along the highway.
Ports computers are used to connect external devices to the central unit.