quantifiers

entries/quantifiers.txt

@@ -1,4 +1,77 @@
 quantifiers
 
-Prev  Up  Next quadruple bucky Home quantum bogodynamics
+In techspeak and jargon, the standard metric prefixes used in the SI (Systeme
+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 decimal
+interpretations in common use:
+
+kilo  (K, KB)  1,024
+mega  (M, MB)  1,048,576
+giga  (G, GB)  1,073,741,824
+tera  (T, TB)  1,099,511,627,776
+peta  (P, PB)  1,125,899,906,842,624
+exa   (EX)     1,152,921,504,606,846,976<37>
+zetta          1,180,591,620,717,411,303,424
+yotta          1,208,925,819,614,629,174,706,176
+
+Here are the SI fractional prefixes:
+
+milli  1000^-1
+micro  1000^-2
+nano   1000^-3
+pico   1000^-4
+femto  1000^-5
+atto   1000^-6
+zepto  1000^-7
+yocto  1000^-8
+
+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’.
+
+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 in
+magnitude) — for example, describing a memory in units of 500K or
+524K instead of 512K — is a sure sign of the marketroid. One example
+of this: it is common to refer to the capacity of 3.5" floppies
+as ‘1.44 MB’ In fact, this is a completely bogus number. The
+correct size is 1440 KB, that is, 1440 * 1024 = 1474560 bytes.
+So the ‘mega’ in ‘1.44 MB’ is compounded of two ‘kilos’, one of
+which is 1024 and the other of which is 1000. The correct number
+of megabytes would of course be 1440 / 1024 = 1.40625. Alas, this
+fine point is probably lost on the world forever.