# Quantity of information

Quantity of information - a numerical characteristic information. It reflects the degree of uncertainty, which disappears after receiving the information.

Probably, you had to watch on TV bingo game. Whenever drops another number, the degree of uncertainty in this draw is reduced by one. You already know the number one, but still do not know all the others. This uncertainty with the numbers getting smaller with every loss a new number. It disappears when the latter becomes known lottery number.

The resulting information reduces the number of possible choices. Complete information leaves no options at all.

The unit of the amount of information is received one bit. This quantity information, where the uncertainty is halved. In other words, the answer to the question, which requires a monosyllabic decision - yes or no.

The bit is too small quantity of information. In practice, often used larger units of information. For example, a sequence of bytes of eight bits. That is, eight bits are used to encode the symbols of the alphabet, a computer keyboard. One byte is also a minimum unit of addressable memory. Contact the memory can be byte, not bit.

In order to measure quantity of information more widely used large derived units:

1 kilobyte (KB) = 1024 bytes

1 megabyte (MB) = 1024 KB

1 gigabyte (GB) = 1024 MB

1 terabyte (TB) = 1024 GB.