Moscow State University of Printing. Computer technology hardware: definition, description and types Interaction of software and hardware

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 very simple version classifications 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 mentioning separately the main elements of computer systems such as motherboard, processor, etc., not included in any of the above classes and being 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 brackets random access memory And hard drives, which refer to 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 thing here is 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, 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:

  • HDD(Winchester);
  • 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 that are responsible for ensuring communication both between individual computer terminals connected directly, and in networks (or even at the level of Internet access). Here the main devices can be identified as follows:

  • 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 modern computer was discussed 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 external and internal devices different types more and more 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.

Regulars of computer stores, regular readers of the magazines “Chip”, “ Home computer"and other magazines and newspapers specializing in computer topics may 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. For implementation network technologies you need to have several computers connected to a network. Comprises system unit, monitor, keyboard. When working with graphical operating systems, the technical tool necessary for work becomes mouse manipulator . System unit a computer is not a single indivisible device. Principle open architecture, implemented in modern PCs, allows you to achieve the desired results during the process of assembling a computer from individual standardized components 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. The 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- input devices graphic information to 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, World Cup – 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 during presentations, conferences, meetings of the organization’s team, in 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.

Sources uninterruptible power supply – 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 magazines and Internet pages already mentioned above, reflecting news from the computer market.

Communication means include local networks. A Local Area Network (LAN) is a connection between multiple PCs using appropriate hardware and software. The word "local" in this name means that all connected PCs are usually located in the same building or neighboring buildings. In addition to LAN, there are other networks:

    MAN (Metropolitan Area Network). In this network, the basis is the connection of systems within the city. Its application area could be a computerized main control system or the management of information about the residents of a large city.

    WAN (Wide Area Network). In this case we are talking about a network that can connect several countries.

    GAN (Global Area Network) stands for a network that connects continents.

Naturally, a PC can work on any of these networks. However, its typical area of ​​application is the local network. Thanks to the open architecture of the network, the computer has the ability to connect to the network.

The benefits that the user will receive from connecting several computers into a network are as follows:

    Data distribution. Data on the network is stored on a central PC and can be accessed by any PC connected to the network, so there is no need to have drives for storing the same information at each workstation.

    Resource distribution. Peripheral (usually expensive) devices can be accessible to all network users, for example, a fax machine or a laser printer.

    Distribution of programs. All network users can have access to programs that have been centrally installed once. Of course, the network version of the corresponding programs should work.

    Email. All network users can send or receive messages.

An enterprise that has a network of several hundred workstations must have a specialist who is responsible for the functioning of the entire network. Such a specialist is called a network administrator.

To protect information, first of all, devices are needed in case of failure of the industrial electrical network. For this purpose, you can use hardware, such as a computer uninterruptible power supply (UPS). It operates in such a way that if the supply voltage drops, the network continues to function for the time necessary to orderly disconnect all users from the network and turn off the central computer without losing data.

As another measure, it is necessary to have at your disposal additional computer, which can replace a failed server or workstation.

Since a large amount of data usually circulates on the network, it is necessary to carefully and systematically take care of the protection of information. For example, additional hard drives (mirror) can be installed on which information is duplicated, or large-capacity drives (streamers) can be used to ensure systematic copying (archiving) of data.

In addition, on the network, each user can have access to all information, i.e. read and change any data. This is usually undesirable, and not just for security reasons.

The corresponding actions of network users are governed by certain access rights, which determine which user is allowed to read or write certain data. To restrict access, distribute network resources and ensure data safety, network administration is required.

The way computers are connected on a network is called topology. Therefore, before talking about individual components, we want to introduce the most important network topologies.

First of all, you should remember that a file server (or just a server) is the central computer of the entire local network, with which workstations (clients) are connected in one way or another.

PC - PC (pseudo-network). The cheapest, although inefficient, solution for data transfer is to connect two PCs via a serial interface (this connection is sometimes called a pseudo-network). In this case, in addition to the interfaces, only a cable connecting the PC is needed. This cable is often called a null modem cable because communication between two PCs occurs without the use of an amplification device and conversion of transmitted and received data.

As already mentioned, a significant advantage serial interface is that the data cable can be much longer than for the parallel interface, since the danger of data loss is much less. Such a null modem cable can be more than 100 m long and allows you to easily connect two PCs.

There are a number of programs designed to organize data exchange. The most famous is LapLink. This program establishes a connection between two PCs both through a parallel interface via a special cable and through a serial interface.

Peer-to-peer network. A peer-to-peer network (Fig. 7.1) does not have a central computer and operates without file backup. Some hardware (hard drives, CD-ROM drives) and, above all, expensive peripheral devices (scanners, printers, etc.), connected to individual PCs, are used together at all workstations. Each user of a peer-to-peer network can determine the access rights of other users to information on their PC. The mechanism for limiting user rights is the ability to block access to the disks of other peripheral devices connected to his computer.

To set up such a network, slightly more hardware is needed than in the case of a pseudonetwork. Each PC on the network must be equipped with a network card, and all workstations must be connected to each other by cables.

If the number of users on a peer-to-peer network exceeds 10, it will slow down. In this case, you need to use more powerful PCs.

Client-server network. A client-server network refers to a network at the center of which is a powerful PC (called a server or file server) connected to individual workstations (clients). This connection of computers is called a client-server network.

Individual workstations use server resources, so they can be equipped more modestly. Network management, in the sense of managing individual workstations, as well as monitoring network peripheral devices such as modems, faxes, etc., is carried out by a special powerful network software. The topology of such networks can be different.

Star topology. In a network with a star topology, the file server is located in the center (Fig. 7.2). This type of network has its advantages:

    Cable damage is a problem for one specific computer and does not generally affect the operation of the network.

    The connection is simply made, since the workstation only needs to connect to the server.

    Reliable protection mechanism against unauthorized access.

    High speed data transfer from workstation to server.

In addition to advantages, there are also disadvantages. Let's list them:

    If the server is not geographically located in the center of the network, then connecting individual remote workstations to it can be difficult and expensive.

    While data transfer from workstation to server (and vice versa) is fast, data transfer speeds between individual workstations are slow.

    The power of the entire network depends on the capabilities of the server. If it is insufficiently equipped or poorly configured, it will be a brake on the entire system.

    Communication between individual workstations is impossible without a server.

Ring topology. In this case, all workstations and the server are connected to each other via a ring through which data and the recipient's address are sent. Workstations receive relevant data by analyzing the address of the sent message. The topology of such a network is shown in Fig. 7.3.

Advantages:

    Since information constantly circulates in a circle between serially connected PCs, the time to access this data is significantly reduced.

    There are no restrictions on the length of the entire network, i.e. All that matters is the distance between individual computers.

Flaws:

    Data transfer time increases in proportion to the number of computers connected in a ring.

    Each workstation is involved in data transfer. The failure of one station can paralyze the entire network if special transition connections are not used.

    When connecting new workstations, the network should be turned off briefly.

Bus topology. Such a network is similar to a central line to which a server and individual workstations are connected. The bus topology has become widespread, which can primarily be explained by low cable requirements and high data transfer rates.

To prevent attenuation of the electrical information signal due to reflections in the communication line of such a network, special plugs called terminators are installed at the ends of the line (Fig. 7.4). Advantages:

    Low cable costs.

    Workstations can be installed or disconnected at any time without interrupting the operation of the entire network.

    Workstations can communicate with each other without the help of a server.

Flaws:

    When a cable breaks, the entire section of the network from the point of break fails.

    Possibility of unauthorized connection to the network, since to increase the number of workstations there is no need to interrupt the network.

The basis for organizing a local network is ordinary PCs connected to the network using an expansion card.

PCs are usually connected to the network using a network card. The exception is a pseudo-network, where PCs are connected using a null modem cable. The network card is installed in one of the free slots on the motherboard.

Network cards are intermediaries between the PC and the network and transmit data via the bus system to the CPU and RAM of the server or workstation.

The network card is equipped with its own processor and memory, usually 8-16 KB in size.

Cables. On a network, data circulates through cables connecting individual computers different ways

depending on the selected network topology.

    A twisted pair is two insulated twisted copper wires. A real cable, as a rule, consists not of one, but of several twisted pairs. For Ethernet, an 8-core cable is used, i.e. physically consisting of 4 twisted pairs.

    1st pair - blue and white with blue stripes;

    2nd pair - orange and white with orange stripes;

    3rd pair - green and white with green stripes;

4th pair - brown and white with brown stripes. Coaxial cable

consists of a central conductor (single-core or stranded) and an outer shielding braid. Between them there is an internal insulating material. External insulation protects against environmental influences. Due to the cable's good immunity to interference, it can be used to connect devices over a distance of several kilometers, with a data transfer rate of 5-10 Mbit/s.

The main characteristic of a coaxial cable is the magnitude of the characteristic impedance. For Ethernet, a cable with a characteristic impedance of 50 Ohms is used. Fiber optic cable. Conductive cable light waves

, is known as fiber optic. It consists of two wires, each of which can transmit data in only one direction. The information signal transmitted through such a wire is not affected by electric fields. Each shell contains reinforcing fibers in the form of layers of plastic.

The data transfer rate over a fiber optic cable is several gigabits per second, and the cable length plays virtually no role. The first problems begin when the cable length is about 50 km, which is more than enough for local networks. But at the same time, it is also the most expensive method of communication; it is primarily beneficial in the field of teleconferencing. Creating a network at the hardware level is completed by connecting all network components with a cable in accordance with its topology.

Thin Ethernet network. After connecting all cable sections with BNC connectors to T connectors, you will get a single cable segment. Terminators (plugs) are installed at both ends (Fig. 7.5).

Ethernet over twisted pair allows connection of computers at speeds up to 100 Mbit. The main disadvantage of this type of network construction is the need to purchase a special hub device if you want to connect three or more PCs into a network.

Each PC must be connected to it using a cable segment (Fig. 7.6). The length of each segment should not exceed 100 m.

The hub is central device in a twisted pair network, the performance of the network depends on it. It connects to the power supply.

Control questions

1. What type computer network used to combine devices within the same building?

2. What device should be used in a twisted pair Ethernet network?

3. Which device allows you to exchange information between PCs via analog communication channels?

4. What types of cables are used in computer networks?

5. What types of network topologies do you know?

Architecture personal computer 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 Digital Watch, providing automatic recording 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

Hard disks HDD

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.

mob_info