zic.tproj/tz-link.htm

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   7 <title>Sources for Time Zone and Daylight Saving Time Data</title>
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  10 <meta name="DC.Creator" content="Eggert, Paul" />
  11 <meta name="DC.Contributor" content="Olson, Arthur David" />
  12 <meta name="DC.Date" content="2004-05-24" />
  13 <meta name="DC.Description"
  14  content="Sources of information about time zones and daylight saving time" />
  15 <meta name="DC.Identifier" content="http://www.twinsun.com/tz/tz-link.htm" />
  16 <meta name="Keywords"
  17  content="database,daylight saving,DST,time zone,timezone,tz,zoneinfo" />
  18 </head>
  19 <body>
  20 <h1>Sources for Time Zone and Daylight Saving Time Data</h1>
  21 <address>
  22 @(#)tz-link.htm 7.42
  23 </address>
  24 <p>
  25 Please send corrections to this web page to the
  26 <a href="mailto:tz@elsie.nci.nih.gov">time zone mailing list</a>.
  27 </p>
  28 <h2>The <code>tz</code> database</h2>
  29 <p>
  30 The public-domain time zone database contains code and data
  31 that represent the history of local time
  32 for many representative locations around the globe.
  33 It is updated periodically to reflect changes made by political bodies
  34 to UTC offsets and daylight-saving rules.
  35 This database (often called <code>tz</code> or <code>zoneinfo</code>)
  36 is used by several implementations,
  37 including
  38 <a href="http://www.gnu.org/software/libc/">the GNU C Library</a> used in
  39 <a href="http://www.linux.org/">GNU/Linux</a>,
  40 <a href="http://www.freebsd.org/">FreeBSD</a>,
  41 <a href="http://www.netbsd.org/">NetBSD</a>,
  42 <a href="http://www.openbsd.org/">OpenBSD</a>,
  43 <a href="http://www.cygwin.com/">Cygwin</a>,
  44 <a href="http://www.delorie.com/djgpp/">DJGPP</a>,
  45 <a href="http://www.hp.com/products1/unix/operating/">HP-UX</a>,
  46 <a href="http://www.sgi.com/developers/technology/irix/">IRIX</a>,
  47 <a href="http://www.apple.com/macosx/">Mac OS X</a>,
  48 <a href="http://h71000.www7.hp.com/">OpenVMS</a>,
  49 <a href="http://wwws.sun.com/software/solaris/">Solaris</a>,
  50 <a href="http://www.tru64unix.compaq.com/">Tru64</a>, and
  51 <a href="http://www.sco.com/products/unixware/">UnixWare</a>.</p>
  52 <p>
  53 Each location in the database represents a national region where all
  54 clocks keeping local time have agreed since 1970.
  55 Locations are identified by continent or ocean and then by the name of
  56 the location, which is typically the largest city within the region.
  57 For example, <code>America/New_York</code>
  58 represents most of the US eastern time zone;
  59 <code>America/Indianapolis</code> represents most of Indiana, which
  60 uses eastern time without daylight saving time (DST);
  61 <code>America/Detroit</code> represents most of Michigan, which uses
  62 eastern time but with different DST rules in 1975;
  63 and other entries represent smaller regions like Starke County,
  64 Kentucky, which switched from central to eastern time in 1991.
  65 To use the database, set the <code>TZ</code> environment variable to
  66 the location's full name, e.g., <code>TZ="America/New_York"</code>.</p>
  67 <p>
  68 In the <code>tz</code> database's
  69 <a href="ftp://elsie.nci.nih.gov/pub/">FTP distribution</a>,
  70 the code is in the file <code>tzcode<var>C</var>.tar.gz</code>,
  71 where <code><var>C</var></code> is the code's version;
  72 similarly, the data are in <code>tzdata<var>D</var>.tar.gz</code>,
  73 where <code><var>D</var></code> is the data's version.
  74 The following shell commands download
  75 these files to a GNU/Linux or similar host; see the downloaded
  76 <code>README</code> file for what to do next.</p>
  77 <pre style="margin-left: 2em"><code><a href="http://www.gnu.org/software/wget/">wget</a> 'ftp://elsie.nci.nih.gov/pub/tz*.tar.gz'
  78 <a href="http://www.gnu.org/software/gzip/">gzip</a> -dc tzcode*.tar.gz | <a href="http://www.gnu.org/software/tar/">tar</a> -xf -
  79 gzip -dc tzdata*.tar.gz | tar -xf -
  80 </code></pre>
  81 <p>
  82 The code lets you compile the <code>tz</code> source files into
  83 machine-readable binary files, one for each location. It also lets
  84 you read a <code>tz</code> binary file and interpret time stamps for that
  85 location.</p>
  86 <p>
  87 The data are by no means authoritative. If you find errors, please
  88 send changes to the <a href="mailto:tz@elsie.nci.nih.gov">time zone
  89 mailing list</a>. You can also <a
  90 href="mailto:tz-request@elsie.nci.nih.gov">subscribe</a> to the
  91 mailing list, retrieve the <a
  92 href="ftp://elsie.nci.nih.gov/pub/tzarchive.gz">archive of old
  93 messages</a> (in gzip compressed format), or retrieve <a
  94 href="ftp://munnari.oz.au/pub/oldtz/">archived older versions of code
  95 and data</a>.</p>
  96 <p>
  97 The Web has several other sources for time zone and daylight saving time data.
  98 Here are some recent links that may be of interest.
  99 </p>
 100 <h2>Web pages using recent versions of the <code>tz</code> database</h2>
 101 <ul>
 102 <li><a href="http://twiki.org/cgi-bin/xtra/tzdate">Date and Time Gateway</a>
 103 is a text-based point-and-click interface to tables of current time
 104 throughout the world.</li>
 105 <li>Fancier web interfaces, roughly in ascending order of complexity, include:
 106 <ul>
 107 <li><a href="http://www.hilink.com.au/times/">Local Times Around the
 108 World</a></li>
 109 <li><a href="http://www.convertit.com/Go/ConvertIt/World_Time/Current_Time.ASP">Current Time in 1000 Places</a></li>
 110 <li><a href="http://timezoneconverter.com/">Time Zone Converter</a></li>
 111 </ul></li>
 112 <li><a href="http://www.holidayfestival.com/">The Worldwide Holiday
 113 &amp; Festival Site</a> lists DST-related clock changes along with
 114 holidays.</li>
 115 <li><a href="http://www.timeanddate.com/worldclock/">The World Clock -
 116 Time Zones</a>
 117 is a web interface to a time zone database derived from
 118 <code>tz</code>'s.</li>
 119 </ul>
 120 <h2>Other time zone database formats</h2>
 121 <ul>
 122 <li>The <a href="ftp://ftp.rfc-editor.org/in-notes/rfc2445.txt">
 123 Internet Calendaring and Scheduling Core Object Specification
 124 (iCalendar)</a> specification published by the <a
 125 href="http://www.ietf.org/html.charters/calsch-charter.html">IETF
 126 Calendaring and Scheduling Working Group (calsch)</a> covers time zone
 127 data; see its VTIMEZONE calendar component.</li>
 128 <li>The <a
 129 href="http://lists.w3.org/Archives/Public/www-rdf-calendar/">www-rdf-calendar</a>
 130 list discusses <a href="http://www.w3.org/RDF/">RDF</a>-based calendar
 131 and group scheduling systems, and has a <a
 132 href="http://www.w3.org/2002/12/cal/#tzd">workspace on time zone
 133 data</a> converted from <code>tz</code>. An earlier <a
 134 href="http://www.w3.org/2000/01/foo">schema</a> was sketched out by <a
 135 href="http://www.w3.org/People/Berners-Lee/">Tim Berners-Lee</a>.</li>
 136 <li><a
 137 href="http://www.calsch.org/ietf/archives/draft-ietf-calsch-many-xcal-02.txt">XCal</a>
 138 was a draft <a href="http://www.w3.org/XML/">XML</a> document type
 139 definition that corresponded to iCalendar.</li>
 140 </ul>
 141 <h2>Other <code>tz</code> compilers</h2>
 142 <ul>
 143 <li><a href="http://www.dachaplin.dsl.pipex.com/vzic">Vzic iCalendar
 144 Timezone Converter</a> describes a program Vzic that compiles
 145 <code>tz</code> source into iCalendar-compatible VTIMEZONE files.
 146 Vzic is freely
 147 available under the <a href="http://www.gnu.org/copyleft/gpl.html">GNU
 148 General Public License (GPL)</a>.</li>
 149 <li><a
 150 href="http://search.cpan.org/dist/DateTime-TimeZone/">DateTime::TimeZone</a>
 151 contains a script <code>parse_olson</code> that compiles
 152 <code>tz</code> source into <a href="http://www.perl.org/">Perl</a>
 153 modules. It is part of the Perl <a
 154 href="http://datetime.perl.org/">DateTime Project</a>, which is freely
 155 available under both the GPL and the Perl <a
 156 href="http://www.perl.com/language/misc/Artistic.html">Artistic
 157 License</a>. DateTime::TimeZone also contains a script
 158 <code>tests_from_zdump</code> that generates test cases for each clock
 159 transition in the <code>tz</code> database.</li>
 160 <li><a href="http://oss.software.ibm.com/icu/">International Components for
 161 Unicode (ICU)</a> contains a C/C++ library for internationalization that
 162 has a compiler from <samp>tz</samp> source into an ICU-specific format.
 163 ICU is freely available under a BSD-style license.</li>
 164 <li><a href="http://joda-time.sourceforge.net/">Joda Time - Java date
 165 and time API</a> contains a class
 166 <code>org.joda.time.tz.ZoneInfoCompiler</code> that compiles
 167 <code>tz</code> source into a Joda-specific binary format. Joda Time
 168 is freely available under a BSD-style license.</li>
 169 </ul>
 170 <h2>Other <code>tz</code> binary file readers</h2>
 171 <ul>
 172 <li>The <a href="http://www.gnu.org/software/libc/">GNU C Library</a>
 173 has an independent, thread-safe implementation of
 174 a <code>tz</code> binary file reader.
 175 This library is freely available under the
 176 <a href="http://www.gnu.org/copyleft/lesser.html">
 177 GNU Lesser General Public License (LGPL)</a>,
 178 and is widely used in GNU/Linux systems.</li>
 179 <li><a href="http://www.bmsi.com/java/#TZ">ZoneInfo.java</a>
 180 is a <code>tz</code> binary file reader written in Java.
 181 It is freely available under the GNU LGPL.</li>
 182 <li><a href="http://s.keim.free.fr/tz/doc.html">Python time zones</a>
 183 is a <code>tz</code> binary file reader written in <a
 184 href="http://www.python.org/">Python</a>. It is freely available
 185 under a BSD-style license.</li>
 186 </ul>
 187 <h2>Other <code>tz</code>-based time zone conversion software</h2>
 188 <ul>
 189 <li><a href="http://java.sun.com/">Sun Java</a> releases since 1.4
 190 contain a copy of a recent <samp>tz</samp> database in a Java-specific
 191 format.</li>
 192 <li><a
 193 href="http://www1.tip.nl/~t876506/AboutTimeZonesHC.html">HyperCard
 194 time zones calculator</a> is a HyperCard stack.</li>
 195 <li><a
 196 href="http://www.cimmyt.org/timezone/">World Time Explorer</a> is a
 197 Microsoft Windows program.</li>
 198 </ul>
 199 <h2>Other time zone databases</h2>
 200 <ul>
 201 <li><a href="http://www.astro.com/cgi-bin/atlw3/aq.cgi?lang=e">Atlas Query
 202 - Astrodienst</a> is Astrodienst's Web version of Shanks's
 203 excellent time zone history atlases published in both <a
 204 href="http://astrocom.com/software/pcatlas.php">computer</a> and <a
 205 href="http://astrocom.com/books/xrefa.php#SHANKS">book</a> form by <a
 206 href="http://astrocom.com/">Astro Communications Services</a>.</li>
 207 <li><a href="http://worldtime.com/">WORLDTIME: interactive atlas,
 208 time info, public holidays</a>
 209 contains information on local time, sunrise and sunset,
 210 and public holidays in several hundred cities around the world.</li>
 211 <li><a href="http://www.worldtimeserver.com/">World Time Server</a>
 212 is another time zone database.</li>
 213 <li><a href="http://tycho.usno.navy.mil/tzones.html">World Time Zones</a>
 214 contains data from the Time Service Department of the US Naval Observatory
 215 (USNO), used as the source
 216 for the <code>usno*</code> files in the <code>tz</code> distribution.</li>
 217 <li><a href="http://www.airportcitycodes.com/aaa/">Airlines, Airplanes
 218 and Airports</a> lists current standard times for thousands of
 219 airports around the world. This seems to be derived from
 220 the <a href="http://www.iata.org/sked/publications/">Standard
 221 Schedules Information Manual (SSIM)</a> of the
 222 the <a href="http://www.iata.org/">International Air Transport
 223 Association</a>,
 224 which gives current time zone rules for
 225 all the airports served by commercial aviation.</li>
 226 </ul>
 227 <h2>Maps</h2>
 228 <ul>
 229 <li>The <a href="http://www.odci.gov/">United States Central
 230 Intelligence Agency (CIA)</a> publishes a <a
 231 href="http://www.odci.gov/cia/publications/factbook/reference_maps/pdf/time_zones.pdf">time
 232 zone map</a>; the
 233 <a
 234 href="http://www.lib.utexas.edu/maps/world.html">Perry-Casta&ntilde;eda
 235 Library Map Collection</a>
 236 of the University of Texas at Austin has copies of
 237 recent editions.
 238 The pictorial quality is good,
 239 but the maps do not indicate summer time,
 240 and parts of the data are a few years out of date.</li>
 241 <li><a href="http://worldtimezone.com/">World timezones map with
 242 current time</a>
 243 has several fancy time zone maps; it covers Russia particularly well.
 244 The maps' pictorial quality is not quite as good as the CIA's
 245 but the maps are more up to date.</li>
 246 </ul>
 247 <h2>Time zone boundaries</h2>
 248 <ul>
 249 <li><a href="http://home-4.tiscali.nl/~t876506/Multizones.html">Time
 250 zone boundaries for multizone countries</a> summarizes legal
 251 boundaries between time zones within countries.</li>
 252 <li>Manifold.net's <a
 253 href="http://www.manifold.net/download/freemaps.html">Free Maps and
 254 GIS Data</a> includes a Manifold-format map of world time zone
 255 boundaries distributed under the GPL. The GeoCommunity's <a
 256 href="http://software.geocomm.com/data/intl_timezones.html">International
 257 Time Zones</a> publishes the same data in other formats.</li>
 258 <li>The US Geological Survey's National Atlas of the United States
 259 publishes the <a href="http://www.nationalatlas.gov/timeznm.html">Time
 260 Zones of the United States</a> in the public domain.</li>
 261 <li>The GeoCommunity lists several commercial sources for <a
 262 href="http://spatialnews.geocomm.com/features/timezones/">International
 263 Time Zones and Time Zone Data</a>.</li>
 264 </ul>
 265 <h2>Civil time concepts and history</h2>
 266 <ul>
 267 <li><a href="http://physics.nist.gov/time">A Walk through Time</a>
 268 surveys the evolution of timekeeping.</li>
 269 <li><a href="http://webexhibits.org/daylightsaving/">About Daylight
 270 Saving Time - History, rationale, laws and dates</a>
 271 is an overall history of DST.</li>
 272 <li><a href="http://toi.iriti.cnr.it/">The
 273 Time of Internet</a>
 274 describes time zones and daylight saving time,
 275 with diagrams.
 276 The time zone map is out of date, however.</li>
 277 <li><a href="http://www.phys.uu.nl/~vgent/idl/idl.htm">A History of
 278 the International Date Line</a> tells the story of the most important
 279 time zone boundary.</li>
 280 <li><a href="http://www.statoids.com/tconcept.html">Basic Time
 281 Zone Concepts</a> discusses terminological issues behind time zones.</li>
 282 </ul>
 283 <h2>National histories of legal time</h2>
 284 <dl>
 285 <dt>Australia</dt>
 286 <dd>The Community Relations Division of the New South Wales (NSW)
 287 Attorney General's Department maintains a <a
 288 href="http://www.lawlink.nsw.gov.au/crd.nsf/pages/time2">history of
 289 daylight saving in NSW</a>.</dd>
 290 <dt>Austria</dt>
 291 <dd>The Federal Office of Metrology and Surveying publishes a
 292 table of <a href="http://www.metrologie.at/pdf/sommerzeit.pdf"
 293 hreflang="de">daylight saving time in Austria (in German)</a>.</dd>
 294 <dt>Belgium</dt>
 295 <dd>The Royal Observatory of Belgium maintains a table of <a
 296 href="http://www.astro.oma.be/GENERAL/INFO/nli001a.html"
 297 hreflang="nl">time in Belgium (in Dutch)</a>.</dd>
 298 <dt>Brazil</dt>
 299 <dd>The Time Service Department of the National Observatory
 300 records <a href="http://pcdsh01.on.br/DecHV.html"
 301 hreflang="pt-BR">Brazil's daylight saving time decrees (in
 302 Portuguese)</a>.</dd>
 303 <dt>Canada</dt>
 304 <dd>The Institute for National Measurement Standards publishes current
 305 and some older information about <a
 306 href="http://inms-ienm.nrc-cnrc.gc.ca/time_services/daylight_savings_e.html">Time
 307 Zones and Daylight Saving Time</a>.</dd>
 308 <dt>Chile</dt>
 309 <dd>WebExhibits publishes a <a
 310 href="http://webexhibits.org/daylightsaving/chile.html"
 311 hreflang="es">history of official time (in Spanish)</a> originally
 312 written by the Chilean Hydrographic and Oceanographic Service.</dd>
 313 <dt>Germany</dt>
 314 <dd>The National Institute for Science and Technology maintains the <a
 315 href="http://www.ptb.de/en/org/4/44/441/dars_e.htm">Realisation of
 316 Legal Time in Germany</a>.</dd>
 317 <dt>Israel</dt>
 318 <dd>The Interior Ministry periodically issues <a
 319 href="ftp://ftp.cs.huji.ac.il/pub/tz/announcements/"
 320 hreflang="he">announcements (in Hebrew)</a>.</dd>
 321 <dt>Mexico</dt>
 322 <dd>The Investigation and Analysis Service of the Mexican Library of
 323 Congress has published a <a
 324 href="http://www.cddhcu.gob.mx/bibliot/publica/inveyana/polisoc/horver/"
 325 hreflang="es">history of Mexican local time (in Spanish)</a>.</dd>
 326 <dt>Malaysia</dt>
 327 <dd>See Singapore below.</dd>
 328 <dt>Netherlands</dt>
 329 <dd><a href="http://www.phys.uu.nl/~vgent/wettijd/wettijd.htm"
 330 hreflang="nl">Legal time in the Netherlands (in Dutch)</a>
 331 covers the history of local time in the Netherlands from ancient times.</dd>
 332 <dt>New Zealand</dt>
 333 <dd>The Department of Internal Affairs maintains a brief history <a
 334 href="http://www.dia.govt.nz/diawebsite.nsf/wpg_URL/Resource-material-Information-We-Provide-About-Daylight-Saving">about
 335 daylight saving</a>. The privately-maintained <a
 336 href="http://www.astrologyhouse.co.nz/timechanges.htm">Time Changes in
 337 New Zealand</a> has more details.</dd>
 338 <dt>Singapore</dt>
 339 <dd><a
 340 href="http://www.math.nus.edu.sg/aslaksen/teaching/timezone.html">Why
 341 is Singapore in the "Wrong" Time Zone?</a> details the
 342 history of legal time in Singapore and Malaysia.</dd>
 343 <dt>United Kingdom</dt>
 344 <dd><a
 345 href="http://www.srcf.ucam.org/~jsm28/british-time/">History of
 346 legal time in Britain</a> discusses in detail the country
 347 with perhaps the best-documented history of clock adjustments.
 348 The National Physical Laboratory also maintains an <a
 349 href="http://www.npl.co.uk/time/summer_time_archive.html">archive
 350 of summer time dates</a>.</dd>
 351 </dl>
 352 <h2>Precision timekeeping</h2>
 353 <ul>
 354 <li><a
 355 href="http://literature.agilent.com/litwebbin/purl.cgi?org_id=tmo&amp;pub_id=5965-7984E">The
 356 Science of Timekeeping</a> is a thorough introduction
 357 to the theory and practice of precision timekeeping.</li>
 358 <li><a href="http://www.ntp.org/">NTP: The Network Time Protocol</a>
 359 discusses how to synchronize clocks of
 360 Internet hosts.</li>
 361 <li><a href="http://gauss.gge.unb.ca/GMT.UT.and.the.RGO.txt"
 362 charset="macintosh">A
 363 Few Facts Concerning GMT, UT, and the RGO</a>
 364 answers questions like "What is the difference between GMT and UTC?"</li>
 365 <li><a
 366 href="http://www.gb.nrao.edu/~rfisher/Ephemerides/times.html">Astronomical
 367 Times</a> explains more abstruse astronomical time scales like TT, TCG,
 368 and TDB.</li>
 369 <li>The <a href="http://www.iau.org/">IAU</a>'s <a
 370 href="http://www.iau-sofa.rl.ac.uk/">Standards Of Fundamental
 371 Astronomy</a> (SOFA) initiative publishes Fortran code for converting
 372 among time scales like TAI, TDB, TT and UTC.</li>
 373 <li><a href="http://www.jpl.nasa.gov/basics/bsf2-3.htm">Basics of
 374 Space Flight - Reference Systems - Time Conventions</a>
 375 briefly explains interplanetary space flight timekeeping.</li>
 376 <li><a
 377 href="http://www.giss.nasa.gov/tools/mars24/help/notes.html">Technical
 378 Notes on Mars Solar Time as Adopted by the Mars24 Sunclock</a> briefly
 379 describes Mars Coordinated Time (MTC) and the diverse local time
 380 scales used by each landed mission on Mars.</li>
 381 <li><a
 382 href="http://hpiers.obspm.fr/eop-pc/products/bulletins/bulletins.html">Bulletins
 383 maintained by the IERS EOP (PC)</a> contains official publications of
 384 the Earth Orientation Parameters Product Center of the
 385 International Earth Rotation Service, the committee that decides
 386 when leap seconds occur.</li>
 387 <li>The <a
 388 href="http://www.mail-archive.com/leapsecs@rom.usno.navy.mil/">Leap
 389 Second Discussion List</a> covers McCarthy and Klepczynski's proposal
 390 to discontinue leap seconds, published in <a
 391 href="http://www.gpsworld.com/">GPS World</a> <strong>10</strong>, 11
 392 (1999-11), 50&ndash;57 and discussed further in R. A. Nelson et al.,
 393 <a href="http://www.cl.cam.ac.uk/~mgk25/time/metrologia-leapsecond.pdf">The
 394 leap second: its history and possible future</a>,
 395 <a href="http://www.bipm.fr/metrologia/metrologia.html">Metrologia</a>
 396 <strong>38</strong> (2001), 509&ndash;529.
 397 <a href="http://www.ucolick.org/~sla/leapsecs/onlinebib.html">The
 398 Future of Leap Seconds</a> catalogs information about this
 399 contentious issue.</li>
 400 </ul>
 401 <h2>Time notation</h2>
 402 <ul>
 403 <li>
 404 <a href="http://www.cl.cam.ac.uk/~mgk25/iso-time.html">A Summary of
 405 the International Standard Date and Time Notation</a> is a good
 406 summary of ISO
 407 8601:1988 - Data elements and interchange formats - Information interchange
 408 - Representation of dates and times (which has been superseded by
 409 <a href="http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=26780">ISO 8601:2000</a>).</li>
 410 <li>
 411 Section 3.3 of <a
 412 href="ftp://ftp.rfc-editor.org/in-notes/rfc2822.txt">Internet RFC 2822</a>
 413 specifies the time notation used in email and <a
 414 href="ftp://ftp.rfc-editor.org/in-notes/rfc2616.txt">HTTP</a> headers.</li>
 415 <li>
 416 <a href="ftp://ftp.rfc-editor.org/in-notes/rfc3339.txt">Internet RFC
 417 3339</a> specifies an ISO 8601 profile for use in new Internet
 418 protocols.</li>
 419 <li>
 420 <a href="http://www.exit109.com/~ghealton/y2k/yrexamples.html">The
 421 Best of Dates, the Worst of Dates</a> covers many problems encountered
 422 by software developers when handling dates and time stamps.</li>
 423 <li>
 424 Alphabetic time zone abbreviations should not be used as unique
 425 identifiers for UTC offsets as they are ambiguous in practice. For
 426 example, "EST" denotes 5 hours behind UTC in English-speaking North
 427 America, but it denotes 10 or 11 hours ahead of UTC in Australia;
 428 and French-speaking North Americans prefer "HNE" to "EST". For
 429 compatibility with <a href="http://www.pasc.org/#POSIX">POSIX</a> the
 430 <code>tz</code> database contains English abbreviations for all time
 431 stamps but in many cases these are merely inventions of the database
 432 maintainers.</li>
 433 </ul>
 434 <h2>Related indexes</h2>
 435 <ul>
 436 <li><a href="tz-art.htm">Time and the Arts</a></li>
 437 <li><a href="http://dmoz.org/Reference/Time/">Open Directory -
 438 Reference: Time</a></li>
 439 <li><a href="http://directory.google.com/Top/Reference/Time/">Google Directory - Reference &gt; Time</a></li>
 440 <li><a href="http://dir.yahoo.com/Science/Measurements_and_Units/Time/">Yahoo! Science &gt; Measurements and Units &gt; Time</a></li>
 441 </ul>
 442 </body>
 443 </html>