The mebibyte is a multiple of the unit byte for digital information. The binary prefix mebi means 220, therefore one mebibyte is equal to 1048576bytes. The unit symbol for the mebibyte is MiB.
The unit was established by the International Electrotechnical Commission (IEC) in 1998. It was designed to replace the megabyte, which is still being used in many contexts to represent 220 bytes, which is incompatible with the definition of the prefix mega in the International System of Units (SI) as a multiplier of 106.
The binary prefixes have been accepted by all major standards organizations and are part of the International System of Quantities. Many Linux distributions use the unit, but it is not widely acknowledged within the industry or media.(Wikipedia)