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| author |   Cameron Katri <me@cameronkatri.com> | 2021-05-09 14:20:58 -0400 |
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| committer | Cameron Katri <me@cameronkatri.com> | 2021-05-09 14:20:58 -0400 |
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diff --git a/system_cmds/zic.tproj/tz-link.htm b/system_cmds/zic.tproj/tz-link.htm new file mode 100644 index 0000000..0e63073 --- /dev/null +++ b/system_cmds/zic.tproj/tz-link.htm @@ -0,0 +1,443 @@ +<?xml version="1.0" encoding="US-ASCII"?> +<!DOCTYPE html + PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" + "DTD/xhtml1-strict.dtd"> +<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> +<head> +<title>Sources for Time Zone and Daylight Saving Time Data</title> +<link rel="schema.DC" href="http://purl.org/DC/elements/1.1/" /> +<meta http-equiv="Content-type" content='text/html; charset="US-ASCII"' /> +<meta name="DC.Creator" content="Eggert, Paul" /> +<meta name="DC.Contributor" content="Olson, Arthur David" /> +<meta name="DC.Date" content="2004-05-24" /> +<meta name="DC.Description" + content="Sources of information about time zones and daylight saving time" /> +<meta name="DC.Identifier" content="http://www.twinsun.com/tz/tz-link.htm" /> +<meta name="Keywords" + content="database,daylight saving,DST,time zone,timezone,tz,zoneinfo" /> +</head> +<body> +<h1>Sources for Time Zone and Daylight Saving Time Data</h1> +<address> +@(#)tz-link.htm 7.42 +</address> +<p> +Please send corrections to this web page to the +<a href="mailto:tz@elsie.nci.nih.gov">time zone mailing list</a>. +</p> +<h2>The <code>tz</code> database</h2> +<p> +The public-domain time zone database contains code and data +that represent the history of local time +for many representative locations around the globe. +It is updated periodically to reflect changes made by political bodies +to UTC offsets and daylight-saving rules. +This database (often called <code>tz</code> or <code>zoneinfo</code>) +is used by several implementations, +including +<a href="http://www.gnu.org/software/libc/">the GNU C Library</a> used in +<a href="http://www.linux.org/">GNU/Linux</a>, +<a href="http://www.freebsd.org/">FreeBSD</a>, +<a href="http://www.netbsd.org/">NetBSD</a>, +<a href="http://www.openbsd.org/">OpenBSD</a>, +<a href="http://www.cygwin.com/">Cygwin</a>, +<a href="http://www.delorie.com/djgpp/">DJGPP</a>, +<a href="http://www.hp.com/products1/unix/operating/">HP-UX</a>, +<a href="http://www.sgi.com/developers/technology/irix/">IRIX</a>, +<a href="http://www.apple.com/macosx/">Mac OS X</a>, +<a href="http://h71000.www7.hp.com/">OpenVMS</a>, +<a href="http://wwws.sun.com/software/solaris/">Solaris</a>, +<a href="http://www.tru64unix.compaq.com/">Tru64</a>, and +<a href="http://www.sco.com/products/unixware/">UnixWare</a>.</p> +<p> +Each location in the database represents a national region where all +clocks keeping local time have agreed since 1970. +Locations are identified by continent or ocean and then by the name of +the location, which is typically the largest city within the region. +For example, <code>America/New_York</code> +represents most of the US eastern time zone; +<code>America/Indianapolis</code> represents most of Indiana, which +uses eastern time without daylight saving time (DST); +<code>America/Detroit</code> represents most of Michigan, which uses +eastern time but with different DST rules in 1975; +and other entries represent smaller regions like Starke County, +Kentucky, which switched from central to eastern time in 1991. +To use the database, set the <code>TZ</code> environment variable to +the location's full name, e.g., <code>TZ="America/New_York"</code>.</p> +<p> +In the <code>tz</code> database's +<a href="ftp://elsie.nci.nih.gov/pub/">FTP distribution</a>, +the code is in the file <code>tzcode<var>C</var>.tar.gz</code>, +where <code><var>C</var></code> is the code's version; +similarly, the data are in <code>tzdata<var>D</var>.tar.gz</code>, +where <code><var>D</var></code> is the data's version. +The following shell commands download +these files to a GNU/Linux or similar host; see the downloaded +<code>README</code> file for what to do next.</p> +<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' +<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 - +gzip -dc tzdata*.tar.gz | tar -xf - +</code></pre> +<p> +The code lets you compile the <code>tz</code> source files into +machine-readable binary files, one for each location. It also lets +you read a <code>tz</code> binary file and interpret time stamps for that +location.</p> +<p> +The data are by no means authoritative. If you find errors, please +send changes to the <a href="mailto:tz@elsie.nci.nih.gov">time zone +mailing list</a>. You can also <a +href="mailto:tz-request@elsie.nci.nih.gov">subscribe</a> to the +mailing list, retrieve the <a +href="ftp://elsie.nci.nih.gov/pub/tzarchive.gz">archive of old +messages</a> (in gzip compressed format), or retrieve <a +href="ftp://munnari.oz.au/pub/oldtz/">archived older versions of code +and data</a>.</p> +<p> +The Web has several other sources for time zone and daylight saving time data. +Here are some recent links that may be of interest. +</p> +<h2>Web pages using recent versions of the <code>tz</code> database</h2> +<ul> +<li><a href="http://twiki.org/cgi-bin/xtra/tzdate">Date and Time Gateway</a> +is a text-based point-and-click interface to tables of current time +throughout the world.</li> +<li>Fancier web interfaces, roughly in ascending order of complexity, include: +<ul> +<li><a href="http://www.hilink.com.au/times/">Local Times Around the +World</a></li> +<li><a href="http://www.convertit.com/Go/ConvertIt/World_Time/Current_Time.ASP">Current Time in 1000 Places</a></li> +<li><a href="http://timezoneconverter.com/">Time Zone Converter</a></li> +</ul></li> +<li><a href="http://www.holidayfestival.com/">The Worldwide Holiday +& Festival Site</a> lists DST-related clock changes along with +holidays.</li> +<li><a href="http://www.timeanddate.com/worldclock/">The World Clock - +Time Zones</a> +is a web interface to a time zone database derived from +<code>tz</code>'s.</li> +</ul> +<h2>Other time zone database formats</h2> +<ul> +<li>The <a href="ftp://ftp.rfc-editor.org/in-notes/rfc2445.txt"> +Internet Calendaring and Scheduling Core Object Specification +(iCalendar)</a> specification published by the <a +href="http://www.ietf.org/html.charters/calsch-charter.html">IETF +Calendaring and Scheduling Working Group (calsch)</a> covers time zone +data; see its VTIMEZONE calendar component.</li> +<li>The <a +href="http://lists.w3.org/Archives/Public/www-rdf-calendar/">www-rdf-calendar</a> +list discusses <a href="http://www.w3.org/RDF/">RDF</a>-based calendar +and group scheduling systems, and has a <a +href="http://www.w3.org/2002/12/cal/#tzd">workspace on time zone +data</a> converted from <code>tz</code>. An earlier <a +href="http://www.w3.org/2000/01/foo">schema</a> was sketched out by <a +href="http://www.w3.org/People/Berners-Lee/">Tim Berners-Lee</a>.</li> +<li><a +href="http://www.calsch.org/ietf/archives/draft-ietf-calsch-many-xcal-02.txt">XCal</a> +was a draft <a href="http://www.w3.org/XML/">XML</a> document type +definition that corresponded to iCalendar.</li> +</ul> +<h2>Other <code>tz</code> compilers</h2> +<ul> +<li><a href="http://www.dachaplin.dsl.pipex.com/vzic">Vzic iCalendar +Timezone Converter</a> describes a program Vzic that compiles +<code>tz</code> source into iCalendar-compatible VTIMEZONE files. +Vzic is freely +available under the <a href="http://www.gnu.org/copyleft/gpl.html">GNU +General Public License (GPL)</a>.</li> +<li><a +href="http://search.cpan.org/dist/DateTime-TimeZone/">DateTime::TimeZone</a> +contains a script <code>parse_olson</code> that compiles +<code>tz</code> source into <a href="http://www.perl.org/">Perl</a> +modules. It is part of the Perl <a +href="http://datetime.perl.org/">DateTime Project</a>, which is freely +available under both the GPL and the Perl <a +href="http://www.perl.com/language/misc/Artistic.html">Artistic +License</a>. DateTime::TimeZone also contains a script +<code>tests_from_zdump</code> that generates test cases for each clock +transition in the <code>tz</code> database.</li> +<li><a href="http://oss.software.ibm.com/icu/">International Components for +Unicode (ICU)</a> contains a C/C++ library for internationalization that +has a compiler from <samp>tz</samp> source into an ICU-specific format. +ICU is freely available under a BSD-style license.</li> +<li><a href="http://joda-time.sourceforge.net/">Joda Time - Java date +and time API</a> contains a class +<code>org.joda.time.tz.ZoneInfoCompiler</code> that compiles +<code>tz</code> source into a Joda-specific binary format. Joda Time +is freely available under a BSD-style license.</li> +</ul> +<h2>Other <code>tz</code> binary file readers</h2> +<ul> +<li>The <a href="http://www.gnu.org/software/libc/">GNU C Library</a> +has an independent, thread-safe implementation of +a <code>tz</code> binary file reader. +This library is freely available under the +<a href="http://www.gnu.org/copyleft/lesser.html"> +GNU Lesser General Public License (LGPL)</a>, +and is widely used in GNU/Linux systems.</li> +<li><a href="http://www.bmsi.com/java/#TZ">ZoneInfo.java</a> +is a <code>tz</code> binary file reader written in Java. +It is freely available under the GNU LGPL.</li> +<li><a href="http://s.keim.free.fr/tz/doc.html">Python time zones</a> +is a <code>tz</code> binary file reader written in <a +href="http://www.python.org/">Python</a>. It is freely available +under a BSD-style license.</li> +</ul> +<h2>Other <code>tz</code>-based time zone conversion software</h2> +<ul> +<li><a href="http://java.sun.com/">Sun Java</a> releases since 1.4 +contain a copy of a recent <samp>tz</samp> database in a Java-specific +format.</li> +<li><a +href="http://www1.tip.nl/~t876506/AboutTimeZonesHC.html">HyperCard +time zones calculator</a> is a HyperCard stack.</li> +<li><a +href="http://www.cimmyt.org/timezone/">World Time Explorer</a> is a +Microsoft Windows program.</li> +</ul> +<h2>Other time zone databases</h2> +<ul> +<li><a href="http://www.astro.com/cgi-bin/atlw3/aq.cgi?lang=e">Atlas Query +- Astrodienst</a> is Astrodienst's Web version of Shanks's +excellent time zone history atlases published in both <a +href="http://astrocom.com/software/pcatlas.php">computer</a> and <a +href="http://astrocom.com/books/xrefa.php#SHANKS">book</a> form by <a +href="http://astrocom.com/">Astro Communications Services</a>.</li> +<li><a href="http://worldtime.com/">WORLDTIME: interactive atlas, +time info, public holidays</a> +contains information on local time, sunrise and sunset, +and public holidays in several hundred cities around the world.</li> +<li><a href="http://www.worldtimeserver.com/">World Time Server</a> +is another time zone database.</li> +<li><a href="http://tycho.usno.navy.mil/tzones.html">World Time Zones</a> +contains data from the Time Service Department of the US Naval Observatory +(USNO), used as the source +for the <code>usno*</code> files in the <code>tz</code> distribution.</li> +<li><a href="http://www.airportcitycodes.com/aaa/">Airlines, Airplanes +and Airports</a> lists current standard times for thousands of +airports around the world. This seems to be derived from +the <a href="http://www.iata.org/sked/publications/">Standard +Schedules Information Manual (SSIM)</a> of the +the <a href="http://www.iata.org/">International Air Transport +Association</a>, +which gives current time zone rules for +all the airports served by commercial aviation.</li> +</ul> +<h2>Maps</h2> +<ul> +<li>The <a href="http://www.odci.gov/">United States Central +Intelligence Agency (CIA)</a> publishes a <a +href="http://www.odci.gov/cia/publications/factbook/reference_maps/pdf/time_zones.pdf">time +zone map</a>; the +<a +href="http://www.lib.utexas.edu/maps/world.html">Perry-Castañeda +Library Map Collection</a> +of the University of Texas at Austin has copies of +recent editions. +The pictorial quality is good, +but the maps do not indicate summer time, +and parts of the data are a few years out of date.</li> +<li><a href="http://worldtimezone.com/">World timezones map with +current time</a> +has several fancy time zone maps; it covers Russia particularly well. +The maps' pictorial quality is not quite as good as the CIA's +but the maps are more up to date.</li> +</ul> +<h2>Time zone boundaries</h2> +<ul> +<li><a href="http://home-4.tiscali.nl/~t876506/Multizones.html">Time +zone boundaries for multizone countries</a> summarizes legal +boundaries between time zones within countries.</li> +<li>Manifold.net's <a +href="http://www.manifold.net/download/freemaps.html">Free Maps and +GIS Data</a> includes a Manifold-format map of world time zone +boundaries distributed under the GPL. The GeoCommunity's <a +href="http://software.geocomm.com/data/intl_timezones.html">International +Time Zones</a> publishes the same data in other formats.</li> +<li>The US Geological Survey's National Atlas of the United States +publishes the <a href="http://www.nationalatlas.gov/timeznm.html">Time +Zones of the United States</a> in the public domain.</li> +<li>The GeoCommunity lists several commercial sources for <a +href="http://spatialnews.geocomm.com/features/timezones/">International +Time Zones and Time Zone Data</a>.</li> +</ul> +<h2>Civil time concepts and history</h2> +<ul> +<li><a href="http://physics.nist.gov/time">A Walk through Time</a> +surveys the evolution of timekeeping.</li> +<li><a href="http://webexhibits.org/daylightsaving/">About Daylight +Saving Time - History, rationale, laws and dates</a> +is an overall history of DST.</li> +<li><a href="http://toi.iriti.cnr.it/">The +Time of Internet</a> +describes time zones and daylight saving time, +with diagrams. +The time zone map is out of date, however.</li> +<li><a href="http://www.phys.uu.nl/~vgent/idl/idl.htm">A History of +the International Date Line</a> tells the story of the most important +time zone boundary.</li> +<li><a href="http://www.statoids.com/tconcept.html">Basic Time +Zone Concepts</a> discusses terminological issues behind time zones.</li> +</ul> +<h2>National histories of legal time</h2> +<dl> +<dt>Australia</dt> +<dd>The Community Relations Division of the New South Wales (NSW) +Attorney General's Department maintains a <a +href="http://www.lawlink.nsw.gov.au/crd.nsf/pages/time2">history of +daylight saving in NSW</a>.</dd> +<dt>Austria</dt> +<dd>The Federal Office of Metrology and Surveying publishes a +table of <a href="http://www.metrologie.at/pdf/sommerzeit.pdf" +hreflang="de">daylight saving time in Austria (in German)</a>.</dd> +<dt>Belgium</dt> +<dd>The Royal Observatory of Belgium maintains a table of <a +href="http://www.astro.oma.be/GENERAL/INFO/nli001a.html" +hreflang="nl">time in Belgium (in Dutch)</a>.</dd> +<dt>Brazil</dt> +<dd>The Time Service Department of the National Observatory +records <a href="http://pcdsh01.on.br/DecHV.html" +hreflang="pt-BR">Brazil's daylight saving time decrees (in +Portuguese)</a>.</dd> +<dt>Canada</dt> +<dd>The Institute for National Measurement Standards publishes current +and some older information about <a +href="http://inms-ienm.nrc-cnrc.gc.ca/time_services/daylight_savings_e.html">Time +Zones and Daylight Saving Time</a>.</dd> +<dt>Chile</dt> +<dd>WebExhibits publishes a <a +href="http://webexhibits.org/daylightsaving/chile.html" +hreflang="es">history of official time (in Spanish)</a> originally +written by the Chilean Hydrographic and Oceanographic Service.</dd> +<dt>Germany</dt> +<dd>The National Institute for Science and Technology maintains the <a +href="http://www.ptb.de/en/org/4/44/441/dars_e.htm">Realisation of +Legal Time in Germany</a>.</dd> +<dt>Israel</dt> +<dd>The Interior Ministry periodically issues <a +href="ftp://ftp.cs.huji.ac.il/pub/tz/announcements/" +hreflang="he">announcements (in Hebrew)</a>.</dd> +<dt>Mexico</dt> +<dd>The Investigation and Analysis Service of the Mexican Library of +Congress has published a <a +href="http://www.cddhcu.gob.mx/bibliot/publica/inveyana/polisoc/horver/" +hreflang="es">history of Mexican local time (in Spanish)</a>.</dd> +<dt>Malaysia</dt> +<dd>See Singapore below.</dd> +<dt>Netherlands</dt> +<dd><a href="http://www.phys.uu.nl/~vgent/wettijd/wettijd.htm" +hreflang="nl">Legal time in the Netherlands (in Dutch)</a> +covers the history of local time in the Netherlands from ancient times.</dd> +<dt>New Zealand</dt> +<dd>The Department of Internal Affairs maintains a brief history <a +href="http://www.dia.govt.nz/diawebsite.nsf/wpg_URL/Resource-material-Information-We-Provide-About-Daylight-Saving">about +daylight saving</a>. The privately-maintained <a +href="http://www.astrologyhouse.co.nz/timechanges.htm">Time Changes in +New Zealand</a> has more details.</dd> +<dt>Singapore</dt> +<dd><a +href="http://www.math.nus.edu.sg/aslaksen/teaching/timezone.html">Why +is Singapore in the "Wrong" Time Zone?</a> details the +history of legal time in Singapore and Malaysia.</dd> +<dt>United Kingdom</dt> +<dd><a +href="http://www.srcf.ucam.org/~jsm28/british-time/">History of +legal time in Britain</a> discusses in detail the country +with perhaps the best-documented history of clock adjustments. +The National Physical Laboratory also maintains an <a +href="http://www.npl.co.uk/time/summer_time_archive.html">archive +of summer time dates</a>.</dd> +</dl> +<h2>Precision timekeeping</h2> +<ul> +<li><a +href="http://literature.agilent.com/litwebbin/purl.cgi?org_id=tmo&pub_id=5965-7984E">The +Science of Timekeeping</a> is a thorough introduction +to the theory and practice of precision timekeeping.</li> +<li><a href="http://www.ntp.org/">NTP: The Network Time Protocol</a> +discusses how to synchronize clocks of +Internet hosts.</li> +<li><a href="http://gauss.gge.unb.ca/GMT.UT.and.the.RGO.txt" +charset="macintosh">A +Few Facts Concerning GMT, UT, and the RGO</a> +answers questions like "What is the difference between GMT and UTC?"</li> +<li><a +href="http://www.gb.nrao.edu/~rfisher/Ephemerides/times.html">Astronomical +Times</a> explains more abstruse astronomical time scales like TT, TCG, +and TDB.</li> +<li>The <a href="http://www.iau.org/">IAU</a>'s <a +href="http://www.iau-sofa.rl.ac.uk/">Standards Of Fundamental +Astronomy</a> (SOFA) initiative publishes Fortran code for converting +among time scales like TAI, TDB, TT and UTC.</li> +<li><a href="http://www.jpl.nasa.gov/basics/bsf2-3.htm">Basics of +Space Flight - Reference Systems - Time Conventions</a> +briefly explains interplanetary space flight timekeeping.</li> +<li><a +href="http://www.giss.nasa.gov/tools/mars24/help/notes.html">Technical +Notes on Mars Solar Time as Adopted by the Mars24 Sunclock</a> briefly +describes Mars Coordinated Time (MTC) and the diverse local time +scales used by each landed mission on Mars.</li> +<li><a +href="http://hpiers.obspm.fr/eop-pc/products/bulletins/bulletins.html">Bulletins +maintained by the IERS EOP (PC)</a> contains official publications of +the Earth Orientation Parameters Product Center of the +International Earth Rotation Service, the committee that decides +when leap seconds occur.</li> +<li>The <a +href="http://www.mail-archive.com/leapsecs@rom.usno.navy.mil/">Leap +Second Discussion List</a> covers McCarthy and Klepczynski's proposal +to discontinue leap seconds, published in <a +href="http://www.gpsworld.com/">GPS World</a> <strong>10</strong>, 11 +(1999-11), 50–57 and discussed further in R. A. Nelson et al., +<a href="http://www.cl.cam.ac.uk/~mgk25/time/metrologia-leapsecond.pdf">The +leap second: its history and possible future</a>, +<a href="http://www.bipm.fr/metrologia/metrologia.html">Metrologia</a> +<strong>38</strong> (2001), 509–529. +<a href="http://www.ucolick.org/~sla/leapsecs/onlinebib.html">The +Future of Leap Seconds</a> catalogs information about this +contentious issue.</li> +</ul> +<h2>Time notation</h2> +<ul> +<li> +<a href="http://www.cl.cam.ac.uk/~mgk25/iso-time.html">A Summary of +the International Standard Date and Time Notation</a> is a good +summary of ISO +8601:1988 - Data elements and interchange formats - Information interchange +- Representation of dates and times (which has been superseded by +<a href="http://www.iso.org/iso/en/CatalogueDetailPage.CatalogueDetail?CSNUMBER=26780">ISO 8601:2000</a>).</li> +<li> +Section 3.3 of <a +href="ftp://ftp.rfc-editor.org/in-notes/rfc2822.txt">Internet RFC 2822</a> +specifies the time notation used in email and <a +href="ftp://ftp.rfc-editor.org/in-notes/rfc2616.txt">HTTP</a> headers.</li> +<li> +<a href="ftp://ftp.rfc-editor.org/in-notes/rfc3339.txt">Internet RFC +3339</a> specifies an ISO 8601 profile for use in new Internet +protocols.</li> +<li> +<a href="http://www.exit109.com/~ghealton/y2k/yrexamples.html">The +Best of Dates, the Worst of Dates</a> covers many problems encountered +by software developers when handling dates and time stamps.</li> +<li> +Alphabetic time zone abbreviations should not be used as unique +identifiers for UTC offsets as they are ambiguous in practice. For +example, "EST" denotes 5 hours behind UTC in English-speaking North +America, but it denotes 10 or 11 hours ahead of UTC in Australia; +and French-speaking North Americans prefer "HNE" to "EST". For +compatibility with <a href="http://www.pasc.org/#POSIX">POSIX</a> the +<code>tz</code> database contains English abbreviations for all time +stamps but in many cases these are merely inventions of the database +maintainers.</li> +</ul> +<h2>Related indexes</h2> +<ul> +<li><a href="tz-art.htm">Time and the Arts</a></li> +<li><a href="http://dmoz.org/Reference/Time/">Open Directory - +Reference: Time</a></li> +<li><a href="http://directory.google.com/Top/Reference/Time/">Google Directory - Reference > Time</a></li> +<li><a href="http://dir.yahoo.com/Science/Measurements_and_Units/Time/">Yahoo! Science > Measurements and Units > Time</a></li> +</ul> +</body> +</html> |