The unit of information is a byte. A memory cell has a capacity of 1 byte if it can store one character – a letter, a number, a punctuation mark, etc. So, a string of text consisting of 10 letters occupies 10 bytes in memory.
A bit is the minimum unit of information. In practice, units are usually used:
byte (8 bits);
kilobytes (1024 bits);
megabytes (1024 kilobytes);
gigabyte (1024 megabytes).
Information processing in a personal computer (PC) is based on the exchange of electrical signals between various devices of the machine. These signals occur in a certain sequence. The sign of the presence of a signal can be indicated by the digit 1, the sign of absence by the digit 0. Thus, two stable states are realized in the PC. With the help of certain sets of digits 0 and 1, any information can be encoded. Each such set of zeros and ones is called a binary code. The amount of information encoded by a binary digit 0 or 1 is called a bit. Using a set of bits, you can represent any number and any sign. Signs are represented by eight–bit combinations of bits – bytes (i.e. 1 byte = 8 bits). For example, the Russian letter A is byte 10000000. Any combination of bits can be interpreted as a number. For example, 110 means the number 6, and 01101100 means the number 108. The number can be represented by several bytes. Thus, in a computer, information is encoded by two types of symbols. This representation corresponds to the number system, which uses only two digital signs – 0 and 1.