Timeline of binary prefixes

This timeline of binary prefixes lists events in the history of the evolution, development, and use of units of measure that are germane to the definition of the binary prefixes by the International Electrotechnical Commission (IEC) in 1998,^[1][2] used primarily with units of information such as the bit and the byte.

Historically, computers have used many systems of internal data representation,^[3] methods of operating on data elements, and data addressing. Early decimal computers included the ENIAC, UNIVAC 1, IBM 702, IBM 705, IBM 650, IBM 1400 series, and IBM 1620. Early binary addressed computers included Zuse Z3, Colossus, Whirlwind, AN/FSQ-7, IBM 701, IBM 704, IBM 709, IBM 7030, IBM 7090, IBM 7040, IBM System/360 and DEC PDP series.

Decimal systems typically had memory configured in whole decimal multiples, e.g., blocks of 100 and later 1000. The unit abbreviation 'K' or 'k' if it was used, represented multiplication by 1000. Binary memory had sizes of powers of two or small multiples thereof. In this context, 'K' or 'k' was sometimes used to denote multiples of 1024 units or just the approximate size, e.g., either '64K' or '65K' for 65536 (2¹⁶).