"If something is measured, then someone needs it." So Mayakovsky could have said, but he was more interested in the stars. However, is there a measure for everything, and is it always worth doing it? We must also leave something to the poets.

To everything else, you can use a meter and caliper.

## What was before the unit of quantity of information?

Even primitive construction could not do without determining the length, width and height. Military operations, which our ancestors were engaged in even before they began to build something, also required the calculation of distances, the need for draft power, etc., etc.

But where to get the units of measurement? The inhabitants of the island, who lacked only a calendar for happiness, also asked this question, but to no avail. Although the solution lay on the surface.

Actually, the question is not that difficult. All the first units were provided by nature. People had arms and legs. It is not surprising that the "elbows" and"feet". "Man is the measure of all things" - the philosophical definition did not arise from scratch.

## No need for accuracy yet

At first, no one really cared about the approximate measurements. But already in the time of the pharaohs, builders began to use more advanced tools. If the pyramid collapsed, no one would be patted on the head. But they are still standing.

When we first needed to measure information, we didn't reinvent the wheel. We used the good old meters and kilograms. Because the information was written down on paper. The paper had weight and volume.

There has never been and could not have been any talk about a unit of quantity of information.

## But then came computers

The question arose at the theoretical stage. Because it became impossible to measure the amount of information in units of length and weight.

And without these data, the computer could not be created. Although computing tools already existed and did their job perfectly. Take "Iron Felix", which is remembered only by those who are well over fifty.

## Number systems

How to count the number of sheep in a flock? It's easy if you know how many fingers are on your hand. One, two… ten. Set one stone aside and repeat the process. This is how the first number system appeared.

And if our ancestors had six fingers instead of five? Would there be a duodecimal system? Rather yes than no. Although the remains of six-toed homo sapiens have not yet been found, suchthe system has been created. The cunning of Babylon used the knuckles of one hand.

It gradually became clear that there can be as many number systems as you like. Hexadecimal will require 16 characters. Octal is enough 8. Binary and even less - only zero and one.

## The "yin" and "yang" of the digital world

The binary number system was the last one. It is simply impossible to think of anything easier. But for a long time no one used it. What can you do, people are used to counting in tens.

So it was until the first computers appeared. To count, you need to have a number system. Here they remembered about zero and one. Because tension is either there or it isn't. I didn't have to invent anything. Everything was already in stock.

The binary system, as it turned out, was invented by the ubiquitous Chinese. Emperor Fu Xi, who was also a philosopher at the same time, gave the definition of the system 4 thousand years before Leibniz was born. An outstanding mathematician and reported this juicy news in 1703.

But how many kilobytes are in a gigabyte, he couldn't say either. There was neither one nor the other.

## Beat and its author

The binary number algebra for a circuit in which current flows was first described by the American Claude Shannon in 1940. He managed to combine electricity and mathematics in his doctoral dissertation. In it, he applied Boolean algebra to describe relay circuits. Logical mathematics operates with two concepts: false and true. Relays and circuit breakers can be either on or off. It is surprising that no one had thought to compare one with the other before.

After 8 years, in 1948, he introduced the unit of quantity of information and called it bit. A short word now known to almost everyone, he borrowed from John Tukey. He did not like long names and used the abbreviation bit instead of Binary digiT. This phrase is translated into Russian as "binary digit". This is how the world learned bit - the smallest unit of information.

In the most general sense, information is the degree of heterogeneity. A completely homogeneous space means a complete absence of information. Accidentally or not, the Lord began the creation of the world by separating light from darkness. At that moment, information appeared, and it was equal to one bit.

## Roulettes are different

Gambling fans might be disappointed. Roulette here does not mean something that bets are made on. There is another measuring tool with the same name. It has millimeters, centimeters, decimeters - units of length measurement.

Each next division on the roulette wheel is 10 times greater than the previous one. So, we get centimeters, decimeters, meters and kilometers. It is clear that such a gradation is associated with the system used to measure the length.

And what about the information roulette? Here I had to compromise my principles. Binary digits do not correspond to decimal units. Because division is based on the power of 2.

## What's the beat?

The next unit is called a byte. To understand how many bits are in 1 byte, you need to raise 2 to the third power. Get eight. The smallest number will be represented as 00000001, the largest 11111111.

Why is this byte length chosen? Partly because the number of possible combinations of zeros and ones is 256. This turned out to be quite enough to encode numbers, the alphabet and service symbols for teletype and telegraph.

But soon a byte was not enough. They didn't get smart for a long time. All subsequent units were assigned already familiar prefixes: "kilo", "mega", "giga", "tera" and so on. It became possible to calculate how many bytes in kbytes and answer how MB differs from GB.

But then the contradictions began.

## How is a kilogram different from a kilobyte?

If we ignore the subject of measurement, then almost nothing. The prefix "kilo" means "thousand". In one case, we have a thousand grams, in the other the same number of bytes. Everything is simple and clear. So a megabyte is a million, a gigabyte is a billion, and a terabyte is a trillion bytes.

There is still a difference. A kilogram is also a kilogram in Africa, but a kilobyte is not always 1 thousand bytes. The thing is that there is no number 1000 in powers of two. kilobyte should contain not a thousand, but 1024 bytes.

## How to measure all the information in the world?

All other divisions of the byte scale are also obtained by raising the number 2 to a power that is a multiple of10:

- megabyte - 1024 KB (220);
- gigabyte - 1024 MB (230);
- terabyte - 1024 GB (240).

In what units the amount of information is measured can be seen in the figure.

The volume of all information in the world in 2009 was estimated at 0.8 zettabytes. And in 2020 it should increase to 44. Is it a lot or a little? If you imagine a video disc of this size, then it would take 63 million years to watch all the films. Ends a series of iotabytes. It contains 1024 zettabytes, or 280 bytes.