Theme 1. Information. Computing systems. Units of information. Hardware

A personal computer (PC) - A set of technical devices and software, combined into a single hardware and software system.

Most ("90%") of modern computers are IBM PC-compatible, which means:

• IBM compatibility - all programs developed for IBM PC will work on all other IBM PC-compatible computers;
• hardware compatibility - most devices are interchangeable.

PC architecture is a structure of the internal organization and the interaction of the main functional modules of the PC (CPU command system, memory structure and a set of main devices). The principle of open architecture is the ability to assemble the computer from devices made by different manufacturers.

Many components are making by Intel, AMD, Cyrix, IBM, Toshiba, Fujitsu, Siemens, Hitachi, Hewlett-Packard, Phillips, Samsung, and others.

System unit

The central processor, the internal memory and the system bus are structurally located on the motherboard in a separate block, which is called a system.

All other devices, both internal and external, are connected to the bus through appropriate cards, which are called adapters or controllers.

Motherboard containing chipset, processor, memory, switches, expansion slots, and other devices that make up the system's computer core.

System bus or bus - a set of lines and chips that perform the transmission of electrical signals of functional purpose. The bus is a connection channel of the microprocessor, RAM and interface devices and is located on the motherboard. The first PCs used 8-bit system bus that worked at 4.7 MHz.

Tires are divided into parallel (consist of several data lines) and consecutive (consist of one line of data transmitted bit per bit). The amount of information transmitted per channel per unit time is called the bandwidth of the channel. In the serial bus, bandwidth is measured in KBit / s, in parallel - in MBit / s.

CPU (Central Processing Unit) - the main computing device that performs arithmetic-logical data actions (executes the program), manages the work of all other devices.

The processor determines the efficiency of the computer as a whole and is a universal device for processing information.

The processor can be programmed to execute an algorithm.

The most important characteristics of the processor are:

• performance (speed), which depends on the clock frequency (Hz);
• bit, which is expressed as the number of internal binary digits.

For example, the processor in 1 MHz performs about 50 million operations per second.

Since 1993, the Intel Pentium processor has begun manufacturing, which today is the standard for many countries around the world.

Widely used processors from AMD (Athlon), Cyrix and others.

The internal (operational) memory of the PC consists of a storage device (RAM) - Random Access Memory (RAM) and a read-only memory (ROM).

Main characteristics of memory: type - defines static or dynamic memory; structure - the number of cells and their number; volume - shows its capacity; sampling time (in nanoseconds, ns).

Structurally, the internal memory is made in the form of memory cells, each of which is given a number (address). The length of each memory cell, which is called a bit, can be 1, 2, 4 and 8 bytes (respectively, 8, 16, 32 and 64 bit).

Programs and data are processed only after they come from the external memory to the internal one. The cell number is its address.

To save the basic software BIOS (the basic system of input-output of the operating system) uses flash memory, which is a kind of permanent memory (ROM) and which can be reprogrammed.

External memory is intended for long-term storage of programs and data. The amount of external memory is much larger than the internal one, but its recording and reading performance is significantly inferior. Typically, the external memory is physically implemented in the form of drives on magnetic and optical disks.

Hard disk (hard drive) is used for accumulation and long-term storage of information. Winchester is arranged in the form of plates that are packed in a single axis of rotation.

Main features of the hard drive:

• the manufacturer - Fujisu, Western;
• Volume ranges from 20 GB to 2 TB or more;
• access time - 7-20 mins; speed of reading and writing up to 5 Mb / s;
• speed of rotation, number of disks and their volume, structure of division into paths, sectors, clusters, cylinders.

Information is recorded in concentric circles (tracks or tracks) on all cylindrical plates.

The present is characterized by the wide use of flash memory (flash drives) with the capacity of 2G ..2T.

Optical (laser) CDs (CDs) are used for both reading and recording information. CDs with a diameter of 120 mm (4.7 "), a thickness of 1.2 mm, a track width of 0.6 microns are issued. The volume of CD information is about 640 MB. The minimum read speed from CD is 150 KB / s (about 75 pages of ASCII text per second).

CD-ROM (Compact Disk Read Only Memory) is a device for reading information from a CD-ROM. The most commonly used optical drives are 48, 52, .. multiple data rates. CD-WR (Compact Disk Write-Read) - a device for reading and writing information on a CD. DVDs have a larger amount of memory.

Cases (tower, desktop) are divided into boxes and towers (small, medium, large).

All external devices are connected to the PC through special ports - connectors that are intended for the electrical connection of the peripheral device to the PC.

Sharing ports on:

• Serial (COM) - to connect the printer, modem, joystick, mouse.
• parallel (LPT) - for connecting a printer, a scanner, disks.

For an external device, you need to have a driver - an application that controls the operation of the device.

Video system (video, monitor, monitor, display, display) is designed for outputting fast text and graphics information.

The video system consists of a display and video adapter (video controller).

The video adapter has its own personal memory - a video memory of 1024 MB in size.

On a modern video adapter, a specialized graphics processor (NVidia GeForce - gaming 3D accelerators, 3Dlabs Wildcat - spatial modeling) is placed, which replaces the work of the CPU for performing 3D graphics operations, Z-buffer support, texture overlay, and more.

The following graphical interfaces are distinguished:

• OpenGL (Selicon Graphics) is supported by many operating systems and uses client-server interaction;
• DirectX with Direct3D subsystem (Microsoft) is supported only by Windows and provides direct access to video memory.

Displays are based on: 1) electron beam tubing or 2) on liquid crystals.

The main characteristics of the display include:

• resolution - the number of pixels horizontally and vertically on the screen;
• a number of colors (palette) - - set of all colors of the video system.
• the size of the visible part of the screen.

The screen size of the display is measured diagonally in inches (25.4 mm) and they are 14 '', 15 '', 17 '', 19 '', 21 '' and more. The video frame rate of 75 Hz (preferably 100 Hz) provides less flashing, which is important for the user's eyes. Today, monitors Samsung, LG, ViewSonic, etc. have been recommended.

A keyboard is the main means of entering character information (letters, numbers, punctuation marks), as well as commands for managing the work of the PC.

For each character, there is a key for you, by pressing on which code of the corresponding character is entered. The most widely used version of the 101-key keyboard.

Printers are intended for the output of information on a paper (special film) of symbolic and graphics information.

Printers are divided into the matrix, inkjet, and laser.

The printer connects to the LPT port (serial). Principal characteristics of printers - printer type, speed, format size and print quality.

Print quality is determined by the printer's resolution, expressed in terms of print dots per inch (dpi).

• Matrix type printers have 9 (180 dpi), 24 pins (heads).
• In the inkjet printer, the image is obtained by applying a thin toner to the paper using an atomizer.
• Laser printers provide the highest speed and best print quality.

The resolution of the laser printer is 300, 600 and 1200 dpi (dots per inch), printing speed - up to 20 pages in 1 minute.

Mouse - input and control device. The mouse is executed with one, two or with three buttons (the company of Microsoft 2, 3 buttons).

Additionally, they can have one or two wheels, which allows you to move the image on the monitor.

Scanner - a device for entering in the PC any information (text, pictures, etc.) from the paper.

The principle of the scanner is based on transforming the image into electrical signals. Uses three types of scanners: handheld, roller, and tablet (desktop).

The main features of scanners are resolution (up to 2400 dpi), speed and scan format.

Modems  - a device for converting digital information into analog and vice versa.

Modems are divided into: external and internal; at maximum data transfer speeds - 38, 56, ... 10,000 KBit / s.