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 1000^(-1), 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 suffix 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 which 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 `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 in magnitude) —- for example, describing a memory in units of 500K or 524K instead of 512K —- is a sure sign of the {marketroid}.
:quantum bogodynamics: /kwon'tm boh`goh-di:-nam'iks/ n. A theory that characterizes the universe in terms of bogon sources (such as politicians, used-car salesmen, TV evangelists, and {suit}s in general), bogon sinks (such as taxpayers and computers), and bogosity potential fields. Bogon absorption, of course, causes human beings to behave mindlessly and machines to fail (and may also cause both to emit secondary bogons); however, the precise mechanics of the bogon-computron interaction are not yet understood and remain to be elucidated. Quantum bogodynamics is most often invoked to explain the sharp increase in hardware and software failures in the presence of suits; the latter emit bogons, which the former absorb. See {bogon}, {computron}, {suit}, {psyton}.