Informatics Informatics and Computer Technologies

Structure of a Personal Computer (hardware) A personal computer consists of hardware and software Hardware includes all physical components of the computer Software includes all programs, which permit the hardware to do its functions and problems which are set. A system device is the main component of the computer and includes all main modules, which define its functions.

Motherboard A motherboard is a physical and logical main stand of the personal computer. All components and devices are connected to it. Parameters of the motherboard define the possibilities of the computer for upgrading in future.

CPU (Central Processing Unit) CPU defines the computing power, does the “thinking” function of the computer The main characteristic of a CPU is bar frequency in MHz Bar frequency defines the number of the operations, which are done per unit of time, i.e., as much as the bar frequency is higher, so the computer “thinking” is faster

Memory Central Processing Unit needs memory to do calculating operation. Central Processing Unit needs memory to do calculating operation. The size and architecture of the memory are important for the level of difficulties of the problems, which it can solve. The size and architecture of the memory are important for the level of difficulties of the problems, which it can solve. There are two kinds of memory: There are two kinds of memory:

ROM ROM – read only memory (without ability for changing), which saves data and programs, that are necessary for the operations of the computer in a static way. Its content is save even when the computer is turned off. The user doesn’t have access to it. BIOS- Basic Input/Output System is recorded on this memory – a number of programs, which send data to the system, identifying the machine, do test procedures, programs, that permit user’s software of to take control over the hardware and etc.

RAM RAM (Random Access Memory)-memory, in which data and programs, that are used at the current moment for execution of tasks are loaded dynamically. The content of this memory disappears when the computer is turned off. The size of the memory reflects on the fastness of the executed programmes. RAM (Random Access Memory)-memory, in which data and programs, that are used at the current moment for execution of tasks are loaded dynamically. The content of this memory disappears when the computer is turned off. The size of the memory reflects on the fastness of the executed programmes. RAM is measured in megabytes (MB) - 1 MB is about 1 million symbols. In the modern computers, that use Windows, it is recommended to use at least 32 MB memory. It is good to use 64 MB memory with multimedia products – graphics, images, sound and animation. RAM is measured in megabytes (MB) - 1 MB is about 1 million symbols. In the modern computers, that use Windows, it is recommended to use at least 32 MB memory. It is good to use 64 MB memory with multimedia products – graphics, images, sound and animation.

Extending slots Extending slots are special slots on the motherboard, which are used when new components are added - sound card, video card, and internal modem. Extending slots are special slots on the motherboard, which are used when new components are added - sound card, video card, and internal modem.

Input - output ports Input - output ports are special slots for attaching input-output devices - mouse, printer, and scanner. Input - output ports are special slots for attaching input-output devices - mouse, printer, and scanner. They are situated on the back panel of the system device. They are situated on the back panel of the system device. Usually the personal computer has two serial (COM1, COM2) or one parallel (LPT1) port Usually the personal computer has two serial (COM1, COM2) or one parallel (LPT1) port Serial ports provide two-ways connection and they are slower. A parallel port is one-way - only for exit and usually it is used for a printer. New computers have a serial (USB) port, which is faster. It is used for installing of printers; special devises - GSM - connection.

Keyboard This is the oldest device for insertion of data and handing over commands to the computer. It works on a type-writer principle In addition to these buttons, there some more buttons on the keyboards that are used for the computer only.

A mouse It is invented to make ones work more comfortable and faster. The mouse has two or three buttons. When the left button is pressed, one indicates the place for the mouse to stop, marks some option, file or place in the text. A menu appears, when the right button is pressed, which shows the operations that can be done at the certain moment. Functions can be set on the third button.

A trackball (static mouse) and a light pen A trackball - There is a build-in little ball in some keyboards. When it spines in different directions, it controls the moving on the screen and with the help of two additional buttons the pressing of the left and the right button of the mouse is simulated. A trackball - There is a build-in little ball in some keyboards. When it spines in different directions, it controls the moving on the screen and with the help of two additional buttons the pressing of the left and the right button of the mouse is simulated. A light pen - It is like a usually pen, trailing by a cable to the system device. Computer registers the place where the pen points. It is used for special functions - for drawing or work with graphical images. A light pen - It is like a usually pen, trailing by a cable to the system device. Computer registers the place where the pen points. It is used for special functions - for drawing or work with graphical images.

Scanner  It is used to read images on paper and transform them into comprehensible for the computer graphic files, which can be seen on the screen, inserted in text documents and various application, printed out and processed by the use of graphic programs. Some models of scanners can scan negatives and slides.

A Monitor  A monitor is a compulsory part of the computer  It is controlled by a video controller (video card), which is situated on the motherboard and transforms the data from the computer into signals that are comprehensible, for the monitor  Monitors follow certain standards, and for the new monitors it is SVGA and dividing capacity 1280х1024. The dividing capacity defines the quality and thickness of the image  Important feature of the monitor is the frequency of refresh rate of the image, which is measured per second. At a higher frequency of the image, the screen is refreshed often and the winking of the screen is avoided, though invisible it can cause tiredness at work for long time.

A printer  A printer is used to print out documents and images.  There are three types of printers depending on the technology of work  MatrixPrinter  Ink Cord Printer  Laser Printer

Some types of printers

Sound  There is a built – in, miniature inner speaker in a personal computer. Its function is to bring out elementary sounds that accompany some of the operations of the computer – deletion of a programme, starting of Windows and etc.  It is necessary a sound card, so one can listen to musical compact discs and use some programmes and supplement that carry out sound information.  It enables the computer to process sounds of any kinds and to control other signal expressing devices. For the reproduction of the sound it is necessary speakers to be switched on, but for a record, a microphone ought to be attached at the back panel side of the system box.

Modem  A modem is necessary for establishing a connection of a computer and a telephone line or cable television net.  The modems that are used for connection with these two nets are different.  They transform the received data from the computer into suitable for the telephone or cable net signals.  Modem is used for a connection with another computer or Internet.

Devices and Carriers for recording data  For the operating of the computer, it is necessary to have space on the computer, where to save the programmes and data. Basically this function is done by the hard disc.  There are many devices for archiving or reinstalling data on other computers - floppy disc, magnet optical device, CD-ROM and DVD.  The capacity of the devices and carriers and for recording data is measured in MB, and at the new computers in GB. 1 GB is equal to 1000 megabyte or 1GB can contain more than thousand million symbols or nearly pages.

Hard Disc Another important feature of the computer is the volume of the saved data on the hard disc. Scanned documents – issues, covers of books, photos, and archive documents and etc. need more space to be saved. Depending on the measures and quality of the scanned image, the parameters vary between 10 to 200 КВ, t. e. fore 1500 scanned figures; it will be necessary 100 МВ disk space.

Floppy Disc Device A floppy disc device is a part of the standard configuration of the computer. It is used for reading and recording data on the diskette. The current standard capacity of the diskette is 1, 44 MB. Diskettes can be used for archiving of data and transmitting them to another computer.

Magnet – optical disc Magnet – optical disc requires magnet – optical device. It is used for archiving and transmitting of data of large volume. Today, it is not used so often, because it is slower than the hard disc and CD-ROM devices.

Compact Disc Devices There are two types: CD-ROM – for reading of compact disc only and CD-WR – for reading and recording on it. They have a great capacity - 650, 700, 750 МВ. CD-ROM – for reading becomes a standard part of the computer device, because they have a number of advantages: they save in a reliable way a great volume of data. That saves space on the hard disc. Recording CD-WR devices are also preferable devices for archive and exchange of a great volume of data. A reliable archive of data base can be created with such a device. Compact discs work on the optical principle. Mono-recordable CD-R (CD-R - Compact Disk - Recordable) - Compact Disk (CD-R W - Compact Disk - Rewriteble – and Recordable(CD-R W - Compact Disk – Rewriteble) for multi-records.

DVD devices They also can be of two types – for reading and for recording data. Digital technology is used when data are recorded, which offers maximum frequency on recording of image and sound

A Personal Computer