1. quantifiers
In techspeak and jargon, the standard metric prefixes used in the SI
(Système International) conventions for scientific measurement have
dual uses. With units of time or things that come in powers of 10, such as
money, they retain their usual meanings of multiplication by powers of
1000 = 10^3. But when used with bytes or
other things that naturally come in powers of 2, they usually denote
multiplication by powers of 1024 = 2^10.Here are the SI magnifying prefixes, along with the corresponding
binary interpretations in common use:
prefix decimal binary
kilo- 1000^1 1024^1 = 2^10 = 1,024
mega- 1000^2 1024^2 = 2^20 = 1,048,576
giga- 1000^3 1024^3 = 2^30 = 1,073,741,824
tera- 1000^4 1024^4 = 2^40 = 1,099,511,627,776
peta- 1000^5 1024^5 = 2^50 = 1,125,899,906,842,624
exa- 1000^6 1024^6 = 2^60 = 1,152,921,504,606,846,976
zetta- 1000^7 1024^7 = 2^70 = 1,180,591,620,717,411,303,424
yotta- 1000^8 1024^8 = 2^80 = 1,208,925,819,614,629,174,706,176
Here are the SI fractional prefixes:
prefix decimal jargon usage
milli- 1000^-1 (seldom used in jargon)
micro- 1000^-2 small or human-scale (see micro-)
nano- 1000^-3 even smaller (see nano-)
pico- 1000^-4 even smaller yet (see pico-)
femto- 1000^-5 (not used in jargon—yet)
atto- 1000^-6 (not used in jargon—yet)
zepto- 1000^-7 (not used in jargon—yet)
yocto- 1000^-8 (not used in jargon—yet)
The prefixes zetta-, yotta-, zepto-, and yocto- have been included in
these tables purely for completeness and giggle value; they were adopted in
1990 by the 19th Conference Generale des Poids et
Mesures. The binary peta- and exa- loadings, though well
established, are not in jargon use either — yet. The prefix milli-,
denoting multiplication by 1/1000, has
always been rare in jargon (there is, however, a standard joke about the
millihelen — notionally, the
amount of beauty required to launch one ship). See the entries on
micro-, pico-, and
nano- for more information on connotative jargon use
of these terms. ‘Femto’ and ‘atto’ (which,
interestingly, derive not from Greek but from Danish) have not yet acquired
jargon loadings, though it is easy to predict what those will be once
computing technology enters the required realms of magnitude (however, see
attoparsec). There are, of course, some standard unit prefixes for powers of 10.
In the following table, the ‘prefix’ column is the
international standard prefix for the appropriate power of ten; the
‘binary’ column lists jargon abbreviations and words for the
corresponding power of 2. The B-suffixed forms are commonly used for byte
quantities; the words ‘meg’ and ‘gig’ are nouns
that may (but do not always) pluralize with ‘s’.
prefix decimal binary pronunciation}
kilo- k K, KB, kay
mega- M M, MB, meg meg
giga- G G, GB, gig gig,jig
Confusingly, hackers often use K or M as though they were suffix or
numeric multipliers rather than a prefix; thus “2K dollars”,
“2M of disk space”. This is also true (though less commonly)
of G. Note that the formal SI metric prefix for 1000 is ‘k’;
some use this strictly, reserving ‘K’ for multiplication by
1024 (KB is thus ‘kilobytes’). K, M, and G used alone refer to quantities of bytes; thus, 64G is 64
gigabytes and ‘a K’ is a kilobyte (compare mainstream use of
‘a G’ as short for ‘a grand’, that is, $1000).
Whether one pronounces ‘gig’ with hard or soft ‘g’
depends on what one thinks the proper pronunciation of ‘giga-’
is. Confusing 1000 and 1024 (or other powers of 2 and 10 close
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Definitions of quantifiers
