Quantifiers

1 definition found

From Jargon File (4.3.1, 29 Jun 2001) [jargon]:

  quantifiers In techspeak and jargon, the standard metric prefixes used
     in the SI (Syste`me 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
     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 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 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" {microfloppies} 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.
  
     [1993 update: hacker Morgan Burke has proposed, to general approval on
     Usenet, the following additional prefixes:
  
     groucho
    10^(-30)
    
     harpo
    10^(-27)
    
     harpi
    10^(27)
    
     grouchi
    10^(30)
    
     We observe that this would leave the prefixes zeppo-, gummo-, and
     chico- available for future expansion. Sadly, there is little immediate
     prospect that Mr. Burke's eminently sensible proposal will be ratified.]
  
     [1999 upate: there is an IEC proposal
     (ftp://ftp.informatik.uni-erlangen.de/pub/doc/ISO/information-units) for
     binary multipliers, but no evidence that any of its proposals are in
     live use.]