81 lines
7.8 KiB
HTML
81 lines
7.8 KiB
HTML
<?xml version="1.0" encoding="ISO-8859-1" standalone="no"?>
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<html xmlns="http://www.w3.org/1999/xhtml"><head><title>quantifiers</title><link rel="stylesheet" href="../../jargon.css" type="text/css"/><meta name="generator" content="DocBook XSL Stylesheets V1.61.0"/><link rel="home" href="../index.html" title="The Jargon File"/><link rel="up" href="../Q.html" title="Q"/><link rel="previous" href="quadruple-bucky.html" title="quadruple bucky"/><link rel="next" href="quantum-bogodynamics.html" title="quantum bogodynamics"/></head><body><div class="navheader"><table width="100%" summary="Navigation header"><tr><th colspan="3" align="center">quantifiers</th></tr><tr><td width="20%" align="left"><a accesskey="p" href="quadruple-bucky.html">Prev</a> </td><th width="60%" align="center">Q</th><td width="20%" align="right"> <a accesskey="n" href="quantum-bogodynamics.html">Next</a></td></tr></table><hr/></div><dt><a id="quantifiers"/><dt xmlns="" id="quantifiers"><b>quantifiers</b></dt></dt><dd><p> In techspeak and jargon, the standard metric prefixes used in the SI
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(Système International) conventions for scientific measurement have
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dual uses. With units of time or things that come in powers of 10, such as
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money, they retain their usual meanings of multiplication by powers of
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<tt class="literal">1000 = 10^3</tt>. But when used with bytes or
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other things that naturally come in powers of 2, they usually denote
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multiplication by powers of <tt class="literal">1024 = 2^10</tt>.</p><p>Here are the SI magnifying prefixes, along with the corresponding
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binary interpretations in common use:</p><div class="literallayout"><p><br/>
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prefix decimal binary<br/>
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kilo- 1000^1 1024^1 = 2^10 = 1,024 <br/>
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mega- 1000^2 1024^2 = 2^20 = 1,048,576 <br/>
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giga- 1000^3 1024^3 = 2^30 = 1,073,741,824 <br/>
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tera- 1000^4 1024^4 = 2^40 = 1,099,511,627,776 <br/>
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peta- 1000^5 1024^5 = 2^50 = 1,125,899,906,842,624 <br/>
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exa- 1000^6 1024^6 = 2^60 = 1,152,921,504,606,846,976 <br/>
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zetta- 1000^7 1024^7 = 2^70 = 1,180,591,620,717,411,303,424 <br/>
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yotta- 1000^8 1024^8 = 2^80 = 1,208,925,819,614,629,174,706,176 <br/>
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</p></div><p>Here are the SI fractional prefixes:</p><div class="literallayout"><p><br/>
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prefix decimal jargon usage<br/>
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milli- 1000^-1 (seldom used in jargon)<br/>
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micro- 1000^-2 small or human-scale (see <a href="../M/micro-.html"><i class="glossterm">micro-</i></a>)<br/>
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nano- 1000^-3 even smaller (see <a href="../N/nano-.html"><i class="glossterm">nano-</i></a>)<br/>
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pico- 1000^-4 even smaller yet (see <a href="../P/pico-.html"><i class="glossterm">pico-</i></a>)<br/>
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femto- 1000^-5 (not used in jargon—yet)<br/>
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atto- 1000^-6 (not used in jargon—yet)<br/>
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zepto- 1000^-7 (not used in jargon—yet)<br/>
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yocto- 1000^-8 (not used in jargon—yet)<br/>
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</p></div><p>The prefixes zetta-, yotta-, zepto-, and yocto- have been included in
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these tables purely for completeness and giggle value; they were adopted in
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1990 by the <span class="foreignphrase"><i class="foreignphrase">19th Conference Generale des Poids et
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Mesures</i></span>. The binary peta- and exa- loadings, though well
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established, are not in jargon use either — yet. The prefix milli-,
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denoting multiplication by <tt class="literal">1/1000</tt>, has
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always been rare in jargon (there is, however, a standard joke about the
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<span class="firstterm">millihelen</span> — notionally, the
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amount of beauty required to launch one ship). See the entries on
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<a href="../M/micro-.html"><i class="glossterm">micro-</i></a>, <a href="../P/pico-.html"><i class="glossterm">pico-</i></a>, and
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<a href="../N/nano-.html"><i class="glossterm">nano-</i></a> for more information on connotative jargon use
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of these terms. ‘Femto’ and ‘atto’ (which,
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interestingly, derive not from Greek but from Danish) have not yet acquired
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jargon loadings, though it is easy to predict what those will be once
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computing technology enters the required realms of magnitude (however, see
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<a href="../A/attoparsec.html"><i class="glossterm">attoparsec</i></a>).</p><p>There are, of course, some standard unit prefixes for powers of 10.
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In the following table, the ‘prefix’ column is the
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international standard prefix for the appropriate power of ten; the
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‘binary’ column lists jargon abbreviations and words for the
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corresponding power of 2. The B-suffixed forms are commonly used for byte
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quantities; the words ‘meg’ and ‘gig’ are nouns
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that may (but do not always) pluralize with ‘s’.</p><div class="literallayout"><p><br/>
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prefix decimal binary pronunciation}<br/>
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kilo- k K, KB, <span class="emphasis"><em>kay</em></span><br/>
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mega- M M, MB, meg <span class="emphasis"><em>meg</em></span><br/>
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giga- G G, GB, gig <span class="emphasis"><em>gig</em></span>,<span class="emphasis"><em>jig</em></span><br/>
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</p></div><p>Confusingly, hackers often use K or M as though they were suffix or
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numeric multipliers rather than a prefix; thus “<span class="quote">2K dollars</span>”,
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“<span class="quote">2M of disk space</span>”. This is also true (though less commonly)
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of G.</p><p>Note that the formal SI metric prefix for 1000 is ‘k’;
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some use this strictly, reserving ‘K’ for multiplication by
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1024 (KB is thus ‘kilobytes’).</p><p>K, M, and G used alone refer to quantities of bytes; thus, 64G is 64
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gigabytes and ‘a K’ is a kilobyte (compare mainstream use of
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‘a G’ as short for ‘a grand’, that is, $1000).
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Whether one pronounces ‘gig’ with hard or soft ‘g’
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depends on what one thinks the proper pronunciation of ‘giga-’
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is.</p><p>Confusing 1000 and 1024 (or other powers of 2 and 10 close in
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magnitude) — for example, describing a memory in units of 500K or
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524K instead of 512K — is a sure sign of the
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<a href="../M/marketroid.html"><i class="glossterm">marketroid</i></a>. One example of this: it is common to
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refer to the capacity of 3.5" floppies as ‘1.44 MB’ In
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fact, this is a completely <a href="../B/bogus.html"><i class="glossterm">bogus</i></a> number. The
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correct size is 1440 KB, that is, 1440 * 1024 = 1474560 bytes. So the
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‘mega’ in ‘1.44 MB’ is compounded of two
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‘kilos’, one of which is 1024 and the other of which is 1000.
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The correct number of megabytes would of course be 1440 / 1024 = 1.40625.
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Alas, this fine point is probably lost on the world forever. [1993 update:
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hacker Morgan Burke has proposed, to general approval on Usenet, the
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following additional prefixes:</p><div class="informaltable"><table border="1"><colgroup><col/><col/></colgroup><tbody><tr><td>groucho</td><td>10^-30</td></tr><tr><td>harpo</td><td>10^-27</td></tr><tr><td>harpi</td><td>10^27</td></tr><tr><td>grouchi</td><td>10^30</td></tr></tbody></table></div><p>We observe that this would leave the prefixes zeppo-, gummo-, and
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chico- available for future expansion. Sadly, there is little immediate
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prospect that Mr. Burke's eminently sensible proposal will be
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ratified.]</p></dd><div class="navfooter"><hr/><table width="100%" summary="Navigation footer"><tr><td width="40%" align="left"><a accesskey="p" href="quadruple-bucky.html">Prev</a> </td><td width="20%" align="center"><a accesskey="u" href="../Q.html">Up</a></td><td width="40%" align="right"> <a accesskey="n" href="quantum-bogodynamics.html">Next</a></td></tr><tr><td width="40%" align="left" valign="top">quadruple bucky </td><td width="20%" align="center"><a accesskey="h" href="../index.html">Home</a></td><td width="40%" align="right" valign="top"> quantum bogodynamics</td></tr></table></div></body></html>
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