The world around is filled with information. Every second, through the senses, a person receives hundreds of signals and messages. It is impossible to ignore such a significant component of life, even a special field of knowledge specializing in information processes and phenomena has appeared - computer science. Its main weapon is smart electronic computers that can quickly and accurately analyze and manipulate data. The methods of presenting information in computers differ from those to which we are accustomed, and provide maximum efficiency of the computing process.
Information
Information is a global concept; it is difficult to give its comprehensive definition. Until now, there is no single general scientific term; each field of knowledge operates with its own idea of information. For simplicity, it can be defined as data on the state of the world in all its manifestations.
Information makes sense only when someone perceives or uses it. Unlike energy or mass, which, as you know, does not disappear, but only transforms, information may well disappear.
The main task of computer science is to learn how to collect, store and transmit data. The implementation of this is not an easy task. Information is different, and each type of information requires a special approach.
Types of information
To date, people have learned to work with a huge variety of data that differ in nature of origin and structure.
The most popular types of information:
- Graphic information is the very first kind of data that mankind has learned to manipulate. It is accessible for perception and does not require special transformations. Cave paintings - the oldest repository of information about the world. They were replaced by painting, photography and technical drawings.
- Numerical information allows you to describe the quantitative characteristics of objects. The importance of this type of data has skyrocketed with the development of trade and money exchange. To successfully store and transmit numerical information, I had to come up with special character systems. Each culture counted money in its own way, so different number systems were formed.
- Textual information is human speech encoded with special characters. With the invention of writing, it became possible to transfer any concept to an arbitrarily large distance, as well as transfer knowledge to future generations. For the convenience of manipulating textual information, mankind had to invent paper and typography.
- Sound information did not give in to a person for a long time. It was only at the end of the 19th century that the first sound recording devices appeared that made it possible to perceive and store data.
- Video information - live graphics - obeyed the man with the invention of the cinematic apparatus.
All these data can be recorded, processed by electronic computers and transmitted from person to person. They can be stored without loss for a long time. There are other types of information with which mankind has not yet learned to work, for example, tactile or taste.
The division of data into types is of great importance for computer science. Forms of information in a computer are based on its features, and each type of data has a specific structure. Thus, symbolic and graphic information are processed differently by the machine.
Work with information
The main stopping points in the information life cycle are as follows:
- perception and collection;
- storage;
- broadcast;
- play or display.
During long-term storage or transmission, data may be distorted or lost. Significant errors violate or completely change the essence of the information, therefore, they must be avoided at all costs.
To facilitate data manipulation, an encoding was invented. The essence of the coding process is that information according to strictly defined rules is transferred to another form, a certain operation is performed on it, and then the reverse transformation takes place.
One of the first successful coding attempts was light signals. Flashing light sources are a convenient way to transmit information over long distances. With the development of technology, people have come up with many more ways to encrypt data: electrical signals, radio waves.
Coding provides greater safety and security of data, allows you to increase the speed of information transfer and facilitate its processing.
Thus, the information cycle takes the following form:
- collection;
- coding;
- storage;
- broadcast;
- decoding;
- reproduction.
During the life cycle, data can be repeatedly encoded and decoded using different code systems. This is necessary to bring information into a more convenient state for a specific operation.
The material basis of information
Any real manipulations can only be performed on material objects that have certain characteristics that can be fixed and measured. The presentation of information in a computer is based on electrical signals.
The machine nodes working with these data are represented by a huge number of tiny elements, which at any given time are in one of two states: on or off. The specific implementation technology may differ for different computers and even for different blocks of the same machine. The off state is indicated by zero - the absence of a signal, on - by unit.
The amount of information received from one structural element is one bit. The word "bit" is derived from the expression binary digit (binary digit). 1 bit is the smallest unit of information. All information in computers is represented by a sequence of bits - zeros and ones. It is amazing what a huge variety of data can be encrypted in such a simple way!
Representation of information in a computer in the form of separate point values is called discrete. Compared to analog, it is easier to implement and makes it easier to handle large amounts of data.
Binary code
A sequence of bits representing some data is called a binary code. With its help, any information can be encoded: numerical, symbolic, graphic.
The rules by which data is converted to machine code are specific to each type. Individual values in them may coincide, so decoding is always performed depending on the context.
The binary representation of information in a computer has several advantages:
- ease of implementation: on-off elements are much simpler and more reliable than three or more positional elements;
- noise immunity: a signal in which there are only two possible states is much easier to perceive;
- simplicity of calculations: binary arithmetic is as simple as possible.
The mathematical basis for presenting information in a computer is the number system with base 2. It is much simpler than the usual decimal system, operates with only two digits - zero and one - and defines the rules for all mathematical operations performed on binary code.
Numerical information
There are three ways to represent numerical information in a computer:
- fixed point number;
- floating point number;
- binary decimal representation.
For numbers with a fixed point, as the name implies, the place of the point (comma) separating the fractional part is strictly defined and fixed.
- If the point is after the last significant digit, the number is an integer.
- The location of the point in front of the first significant digit corresponds to the correct fraction (less than one modulo).
To determine the sign, the very first digit is highlighted. Positive numbers have 0 in it, negative numbers have 1.
The main advantage of this form of representation is the absence of rounding errors in the calculations. The main disadvantage is the limited range of values depending on the discharge grid of a particular computer.
Floating-point numbers are represented by a combination of mantissa and order values. This form of recording is called semi-logarithmic.
The accuracy of calculations for such a representation depends on the length of the mantissa: during rounding, extra digits can be cut off.
Both fixed-point numbers, and mantissa, and the order of floating-point numbers are represented in the binary system.
The binary-decimal representation of numbers is provided by special processors in the computer. The number is treated as a decimal, but each digit is represented by a binary tetrad. This reduces the processing time for large arrays of decimal numbers.
Text information
To present textual information in a computer, special tables are used in which each character is assigned a unique binary code.
In the most popular coding ASCII (American Code for International Exchange), 8 bits - 1 byte are allocated per character. There are 256 unique combinations for a code unit of this size, therefore, 256 different text characters can be encoded. In addition to letters of different alphabets, the table takes into account mathematical operators, punctuation marks and other special elements.
Of course, 256 combinations are too few for our multicultural world. Some languages themselves contain more letters. In Unicode tables, we increased the size of the basic unit of code by allocating 2 bytes (16 bits) for it. This allowed to increase the encoding limit to 65536 elements.
Raster graphics
Representation of graphic information in a computer is called matrix. It is based on dividing the image into rows of points (pixels). For each pixel, information about the position, color and brightness is stored separately.
In black-and-white images for a point, it is enough to indicate "degree of grayness" - one of 256 gradations of gray color. To do this, 1 byte (8 bits) is allocated.
Color illustrations require more data. To encode information about the color of a point, it is represented as a composition of three basic colors: red, green and blue. This is a Red-Green-Blue - RGB model. Encoding one point of a color image requires 24 bits - one byte (8 bits) for each component.
Vector graphics
An image can be described in another way. For this, it is divided into elementary figures - segments, arcs, circles. Each part can be described using mathematical formulas. So, a circle is represented by a combination of the coordinates of the center and the radius of the circle. This way of describing graphics is called vectorial.
Sound information
The ways of presenting information about sounds in a computer are much more complicated. They are actively developing, but still far from standardization. There are two main areas of audio processing:
- Frequency Modulation (FM) is an attempt to decompose a sound into a sequence of simple correct harmonic signals, the parameters of which can be described. The main difficulty is that the sound is continuous in nature, and the conversion of an analog signal to a discrete one is always accompanied by data loss.
- Tabular-wave synthesis involves the use of samples - samples of sounds. This encodes the type of musical instrument, pitch, intensity and duration of the signal. The quality of the sound obtained is higher than in the previous method, since real samples are used.
The world is filled with information of various kinds. To work with it, a man came up with coding - translating complex data into a simple form for the convenience of storage, transmission and processing. In a computer, the presentation of information is carried out in the form of a binary code - a sequence of individual bits. Any data can be encrypted using this method. The computer performs all operations on numbers according to the rules of the binary number system.