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

1. Computer science and its role in modern life

The term "informatics" comes from the word information - information about anything that is displayed in the form of specific data.

Information exists in various forms - in the form of sounds, gestures, written signs, etc., and it is characterized by attributes such as authenticity, completeness, relevance, usefulness, and comprehensiveness.

Humanity has always been interested in the possibility of saving and transmitting information. A storage tool is an object for storing information.

The bearer of information may be various subjects and phenomena, including human memory.

For the transfer of information used tablets, papyri, etc., but today - video, magnetism, light, etc.

Information activity of a person is a process that involves the acquisition, transformation, accumulation, storage, transmission, presentation of information.

An expert should read about one hundred pages of technical content every day.

Computer Science is a science about the laws and methods of measuring, storing, processing and transmitting information with the help of mathematical, software, technical means.

Computer Science was considered for a long time as part of mathematics.

Technology is a way of mastering the material world of man.

Includes three components: informational (scientific principles and justification), material (tools) and social (professionals with professional skills).

The concept of information technology appeared with the emergence of an information society, the basis of social dynamics in which there is no traditional material, and information resources: knowledge, science, organizational factors, intellectual ability, initiative, creativity, etc.

Academician Glushkov V. interpreted information technology as a human-machine technology for the collection, processing, and transmission of information based on the use of computer technology.

This technology is rapidly developing, covering all types of social activities: production, management, science, education, financial and banking operations, medicine, and others.

The formation of "Computer Science" as a scientific discipline refers to the 60s of the 20th century and was conditioned by the emergence of computers as a universal means of information processing.

Purpose of the computer - processing of numerical, symbolic, graphics, sound and other information after the request of a person:

Information -> Enter -> Computer -> Output -> Information`

For such a transformation it is necessary to have appropriate algorithms and programs.

Numbers or symbols that represent a qualitative sign of the essence are data that can be transmitted, processed, stored.

Object - phenomenon -> Property - attributes -> Number - data

A personal computer (PC, PC) is not a large computing machine as a device for the accumulation, processing, and transmission of information at any distance.

The PC is the main device for integrating the people of the globe into one information network (Internet, E-mail).

The PC works like a music center, a video recorder, a typewriter, etc. Modern technology no longer works without computer control.

2. History of development and principles of work of computers

The formation of computer science was preceded by a long historical path of appearance and improvement of computing devices.

In ancient China, about 4,000 years ago, the inventor was invented.

The Greeks and Romans began to use the abacus - counter board for about 2,000 years ago.

In 1642, the French mathematician Blaise Pascal invented the calculator - a mechanical device for performing addition and subtraction of numbers.

The German mathematician Leibnitz perfected the additive for multiplying and dividing.

The main ideas of the analytical machine were proposed by Charles Babbage in the middle of the XIX century, which showed that any analytical machine should have memory and managed by the program.

In 1945, mathematician John von Neumann showed that all computers should work on some general principles and must have devices: arithmetic-logical; a control unit; a storage device; I / O devices.

Each of these devices must meet certain requirements:

• the principle of random access to the main memory is based on the fact that the processor at any moment of time is available any memory cell, and for this purpose, it should have a name - its serial number (cell address);
• the principle of saving the program is based on the fact that in order to solve the problem, the program should be stored in the main memory, along with the data processed by this program, which makes the computer a universal device for processing information.

The first computers worked on the lamps, were cumbersome, heavy, requiring intensive cooling.

The first lamp computer "ENIAC" was built in 1945 in the United States (Alabama).

In Ukraine, one of the first computers was created in 1951 in Kiev at the Institute of Cybernetics them. Glushkov under the direction of academic Lebedev and was located in the church of St. Panteleimon (Theophany).

In the 1970s, the first mini-computers were created, and in 1975, the first Altari 8800 PC based on the Intel 8080-based 8-bit microprocessor.

In 1981 , IBM released the 16-bit PC IBM PC XT (eXtended Technology) on based on the processor 8088 (10 MB hard disk), has published documentation and software specifications, which allowed other firms to complement its hardware and software.

3. Computing systems

Any information (text, music, images, etc.) for its processing by the computer must be converted into a numeric form.

The calculation system defines the rules for writing numbers and executing arithmetic operations over them (+ - * /).

In computer science, three basic systems of calculation are used - binary, octal and hexadecimal.

Any information in the PC appears in the binary code. In particular, machine commands are represented by two characters 0 and 1 ("yes" and "no", "is" and "no").

These codes have two main fields: the operation field - the binary operation code and field address - the number of data cells over which this operation is performed and where to send the result of the operation.

The presentation of data and programs in binary form is conditioned by the principle of PC operation. It's almost instantaneous to determine if there is a voltage in a given cell (1) or not (0) on RAM; a dipole is "magnetized" or not on the HDD; the reflection of the laser beam is or not on the CD.

The octal computing system uses numbers from 0 to 7.

To write data in a PC memory, a hexadecimal encoding system is used, in which, except for numbers from 0 to 9, letters of the Latin alphabet are used: A = 10, B = 11, C = 12, D = 13 , E = 14, F = 15.

Between the decimal, binary and hexadecimal computing systems there is a unique match:

Example 1. Write the numbers 24 ₍₁₀₎ and 16 ₍₁₀₎ in the binary code. Make them and translate the result into a decimal number.

Adding two binary numbers:

Transmission from binary system to decimal:

Character encoding

To process the text information on a PC, each its symbol is encoded by some number. The correspondence between a set of letters and a number is called the character encoding. The character encoding table with 8-bit numbers is called ASCII (American Standard Coding for Information Interchange). The first part of the table (codes 0-127) includes signs, Arabic numerals, Latin alphabet, and is generally accepted by the whole world. In the second half of the table (codes 128-255), there is a national alphabet, as well as special characters.

Part of the code page 866 for MS-DOS

Example. Record the sequence of letters "ABC" in the binary code.

Units of measurement of information

Bit (binary digit) - a binary digit that accepts values 0 or 1, is the smallest unit of measurement of information.

A bit can also be represented as a cell (memory cell).

Binary elements that are grouped are called memory registers. This indicates the length of the register - the number of binary elements in the group.

Computer commands work not with separate bits, but with their registers.

Byte (byte) - eight consecutive bits, is the basic unit of measurement of computer information.

In eight binary discharges, there are 2 ⁸ = 256 integers (from 0 to 255), which is sufficient for the 8-bit designation of each large, small letter of the English and national alphabets, numbers, signs, etc.

Other units of information are also used, for example, the word 16 bits (2 bytes), the double word is 32 bits (4 bytes) and 64 bits (8 bytes), etc.

To measure large volumes of information, the following units of measurement (sets of bit) are used:

1 kilobyte (K) = 1024 = 2 ¹⁰ bytes (B) = 10 ³ B

1 megabytes (M) = 1048576 = 2 ²⁰ B = 2 ¹⁰ KB = 10 ⁶ B

1 Gigabyte (G) = 1073741824 = 2 ³⁰ B = 2 ²⁰ KB = 2 ¹⁰ MB = 10 ⁹ B

1 terabyte (T) = 2 ⁴⁰ B = 2 ³⁰ KB = 2 ²⁰ MB = 10 ¹² B

If one letter in ASCII code is 1 Byte, then the encyclopedia approximates approximately 120 MB, the newspaper 150 KB, person in 70 years of life says 10 GB.

4. 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.

5. Self-checking

1. What does computer science study?
2. What is the information?
   
3. What is an information system?
4. What is the coding system called binary code?
5. What is a bit?
6. How many bits are needed to encode 512 different independent values?
7. In what units is the capacity of information measured?
8. What is a numerical system?
9. What types of calculations do you know?
10. Which numerical system is used to represent numbers in computer memory?
11. What are the rules for translating numbers from the decimal number system?
12. By what rule translate numbers into a decimal number system?
13. What is the architecture of a computer? The general structure of the computer?
14. Principles of modern computer architecture?
15. Classification of the PC according to the level of specialization, compatibility?
16. Why does it have a hard drive? What is the capacity of modern hard drives?
17. How are the read and write operations in the HDD?
18. What is the formatting of magnetic disks?
19. What are the standard disk interfaces?
20. What parameters affect the speed of a hard drive? How?
21. What is a floppy disk? What is the difference between it and the hard disk?
22. What are the rules to follow when using a floppy disk?
23. What types of drives are on optical drives? How do they differ from each other?
24. How is CD information readable?
25. What is the speed of data transfer in optical media?
26. What does the expression "monitor resolution 1024x768" mean?
27. What consumer parameters do you know about monitors?
28. What is a video adapter? What is it for?
29. What is the essence of video acceleration?
30. With the help of the keys of a group, you can enter an extended ASCII code?
31. Where are the function keys on the keyboard?
32. What devices are called peripherals?
33. Describe the principle of matrix printers.
34. What do you know about the consumer characteristics of the printers?
35. In which units do the resolution of printers and scanners be measured?
36. What is the principle of laser printers?
37. What color model is implemented in color inkjet printers?
38. Why are scanners designed? In what cases should they be used?
39. What types of scanners do you know? What is the difference between them?
40. What features do modems do?