How many megabytes in a gigabyte?

The main snag is that The amount of information can be measured in both binary and decimal systems. In addition, there are various standards of units for measuring the amount of information. This causes confusion and makes it difficult to determine exactly how many megabytes are in a gigabyte.

Actually, prefixes "kilo", "mega", "giga-" and so on are used in the International System of Units (SI) and denote the powers of the number ten. Therefore, if you think logically, in one gigabyte there should be 1000 megabytes. But why is your operating system sure that there are 1024 of them?

The fact is that developers of many modern operating systems use the standard memory JEDEC 100B.01 (the standard of the Joint Engineering Council forelectronic devices), according to which the prefixes accepted in the SI system can denote not a power of ten, but a power of two (that is, the standard uses not a decimal number system, but a binary one). Therefore, one gigabyte by the standard JEDEC will be equal to 1024 megabytes.

And manufacturers of hard drives and flash drives use Standards adopted by the International Electrotechnical Commission (IEC). According to these standards, SI prefixes are used to designate degrees of the number ten. Therefore, one gigabyte should be 1000 megabytes and no more megabytes. GOST 8.417-2002, regulating the names of units of measurement in the territory of Russia, also adheres to this point of view.

If it is important to emphasize that we are talking about a binary number system, It is necessary to use not decimal consoles, but binary (binary). In this case 1024 bytes will be equal to one kibibyte, 1024 kibibytes to one mebibyte, 1024 mebibytes to one gibi-byte. It is these binary attachments adopted in the IEC standard.

The problem is binary attachments, although they are correct, but are practically not used. First, historically, it turned out thatdecimal consoles are used to denote the units of the amount of information in the binary system. Secondly, binary consoles are simply not very euphonious.

So an ordinary user is unlikely to encounterunit of measurement "gibibyte", because almost no one uses it. And how can he determine how many megabytes in a gigabyte in this particular case are 1000 or 1024? Attention should be paid to writing a unit for measuring the amount of information.

According to the proposal of the IEC, if a binary kilobyte / megabyte / gigabyte is implied, the notation must begin with a capital letter, for example, GB, Gbyte, GB. This designation indicates that the gigabyte in this case is 1024 megabytes. If the first letter in the notation is lowercase (gbyte, gbyte, gb), we mean a decimal ("commercial") gigabyte, consisting of 1000 megabytes.

As you can see, in the designation of units of measurement of the volume of information, decimal SI-prefixes, which are used even in those cases where the IEC standard should use binary prefixes. Therefore, in gigabyte it turns out to be 1000, then 1024 megabytes.

It's easiest to remember that manufacturers of hard drives and flash drives use "correct" gigabytes, decimal. And the manufacturers of RAM,video memory, CDs, as well as Microsoft and Apple (developers of OS Windows and Mac OS X, respectively) and software developers use binary gigabytes containing 1024 megabytes (which it would be correct to call gibibytes and mebibytes).