Note that 'exa' now officially means 10

^{18} even in the context of

data processing. The prefixes

kilo,

mega,

giga,

tera,

peta, exa,

zetta,

yotta always refer to powers of 10.

To refer to powers of 2^{10} (powers of 1024), use the new binary prefixes kibi, mebi, gibi, tebi, pebi, and exbi. So

1 exabyte = 1 EB = 10^{18} bytes

1 exbibyte = 1 EiB = 1024^{6} bytes

These new prefixes were created in December 1998 by the International Electrotechnical Commission: see the node prefixes for binary multiples for fuller explanation.

It is permissible to use terms like 'exabyte' to mean exbibyte on a temporary basis until industry standards have shifted to the new terms.

The prefix 'exa' was originally adopted by the fifteenth CGPM of the SI in 1975. It comes from an alteration of the Greek for 'six'.