I used to have a dual booting system with windows and Linux. In windows the size of the partition will be shown Mb(Megabyte) and in Linux it will be shown in Mib. For a long time I was thinking that both are same it just different symbols for same measurement. But it is wrong. In general the prefix “Mega” denotes 10 power 6. Mib which is abbreviation of “Mebibyte” denotes 2 power 20. In computer terms “Mega” was for some time used to denote 2 power 20, which was in conflict with SI definition of “Mega”.
The prefix mebi is derived as a mnemonic from the words mega and binary, indicating its origin in the closeness in value to the SI prefix mega.