sistem saati ne demek?

Bilgisayar bilimi ve bilgisayar programlamasında sistem zamanı, bir bilgisayar sisteminin zaman geçişi kavramını temsil eder. Bu anlamda, zaman, takvim üzerinde gün geçişi de içerir.

Sistem saati, bir çağrı adı verilen bazı keyfi başlangıç tarihlerinden bu yana gerçekleşen kenelerin sayısının basit bir sayımı olarak uygulanan bir sistem saatiyle ölçülür. For example, Unix and POSIX-compliant systems encode system time ("Unix time") as the number of seconds elapsed since the start of the Unix epoch at 1 January 1970 00:00:00 UT, with exceptions for leap seconds. Systems that implement the 32-bit and 64-bit versions of the Windows API, such as Windows 9x and Windows NT, provide the system time as both SYSTEMTIME, represented as a year/month/day/hour/minute/second/milliseconds value, and FILETIME, represented as a count of the number of 100-nanosecond ticks since 1 January 1601 00:00:00 UT as reckoned in the proleptic Gregorian calendar.

Sistem saati, insanların anlaması için daha uygun bir form olan takvim süresine dönüştürülebilir. Örneğin, çağın başlangıcından bu yana 1.000.000.000 saniyelik Unix sistem saati, 9 Eylül 2001 01:46:40 UT takvim süresine çevrilir. Bu tür işlemleri gerçekleştiren kitaplık altprogramları, saat dilimleri, gün ışığından yararlanma saati (DST), sıçrama saniyeleri ve kullanıcının yerel ayarları için yapılan ayarlamalarla da ilgilenebilir. Takvim zamanlarını sistem zamanlarına dönüştüren kitaplık rutinleri de genellikle sağlanmaktadır.

Diğer zaman ölçümleri

Sistem zamanı ile yakından ilişkili olan süreç zamanı, yürütmekte olan bir işlem tarafından tüketilen toplam işlemci saatinin bir sayısıdır. Sırasıyla, kullanıcı kodu ve sistem çekirdeği kodunu gerçekleştirmek için harcanan süreyi temsil eden kullanıcı ve sistem CPU süresine bölünebilir. İşlem süreleri, CPU talimatlarının veya saat çevrimlerinin bir toplamıdır ve genellikle duvar zamanı ile doğrudan bir bağıntıya sahip değildir.

Dosya sistemleri, her bir dosya ve dizinin dosya denetim bloğuna (veya inode'una) zaman damgalarını depolayarak, dosyaların oluşturulduğu, değiştirildiği ve / veya erişildiği süreleri tutar.

Uygulama

Sistem saati, periyodik olarak CPU'yu kesen ve daha sonra bir zamanlayıcı kesme servisi rutini yürütmeye başlayan programlanabilir bir zaman sayacı olarak uygulanır. Bu rutin sistem saatine bir kron ekler (basit bir sayaç) ve kesintiden önce CPU'nun yaptıklarına geri dönmeden önce diğer periyodik temizlik görevlerini (önleme vs.) gerçekleştirir.

Sistem zamanı alınıyor


{{#time:d F Y H:i:s}} UTC

Aşağıdaki tablolar, çeşitli işletim sistemlerinde, programlama dillerinde ve uygulamalarda sistem saatini alma yöntemlerini göstermektedir. (*) Ile işaretlenmiş değerler sisteme bağlıdır ve uygulamalar arasında farklılık gösterebilir. Tüm tarihler Gregoryen veya Gregoryen takvimi olarak verilmiştir.

Bir uygulamanın zaman ölçümünün çözünürlüğünün bu ölçümlerin aynı doğruluğunu ima etmediğini unutmayın. Örneğin, bir sistem, geçerli saati mikrosaniye cinsinden ölçülen bir değer olarak geri getirebilir, ancak aslında sadece 100 Hz (10 ms) frekanslı tek tek saat işaretlerini ayırt edebilecek durumdadır.

İşletim sistemleri

İşletim sistemi	Komut veya işlev	Çözüm	Çağ veya aralık
Android	`java.lang`<wbr/>`.System.currentTimeMillis()`	1 ms	1 Aralık 1970
BIOS (IBM PC)	`INT 1Ah, AH=00h`¹	54.931 ms 18.204 Hz	Geçerli günün gece yarısı
`INT 1Ah, AH=02h`²	1 s	Geçerli günün gece yarısı
`INT 1Ah, AH=04h`³	1 gün	1 Ocak 1980 - 31 Aralık 1999 veya 31 Aralık 2079 (sisteme bağlı)
CP/M Plus	System Control Block:⁴ `scb$base+58h`, Days since 1 Jan 1978 `scb$base+5Ah`, Hour (BCD) `scb$base+5Bh`, Minute (BCD) `scb$base+5Ch`, Second (BCD)	1 s	1 Ocak 1978 - 20 Eylül 2067
BDOS function `69h` (`T_GET`):⁵ `word`, Days since 1 January 1978 `byte`, Hour (BCD) `byte`, Minute (BCD) `byte`, Second (BCD)
DOS (Microsoft)	`DATE` `TIME`	10 ms	1 Ocak 1980 - 31 Aralık 2099
`INT 21h, AH=2Ch SYSTEM TIME`⁶</tt> `INT 21h, AH=2Ah SYSTEM DATE`⁷</tt>
iOS (Apple)	`CFAbsoluteTimeGetCurrent()`⁸	< 1 ms	1 Ocak 2001 ±10,000 yıl
Mac OS (Apple)	`CFAbsoluteTimeGetCurrent()`⁹	< 1 ms¹⁰¹¹	1 Ocak 2001 ±10,000 yıl¹²¹³
OpenVMS (HP)	`SYS$GETTIM()`	100 ns	17 Kasım 1858'den AD 31.086'a
z/OS (IBM)	`STCK`¹⁴	2<sup>−12</sup> μs 244.14 ps¹⁵	1 Ocak 1900 - 17 Eylül 2042 UT¹⁶
Unix, POSIX (ayrıca bakınız C tarih ve saat işlevleri)	`date` `time()`	1 s	(*) 1 Ocak 1970 t- 19 Ocak 2038 1 Ocak 1970 - AD 292,277,026,596
<tt><span class="plainlinks">{{man\|sh\|gettimeofday\|SUS	inline}}()</span></tt>	1 μs
<tt><span class="plainlinks">{{man\|sh\|clock_gettime\|SUS	inline}}()</span></tt>	1 ns
Windows (Microsoft)	`GetSystemTime()`	1 ms	1 Ocak 1601 - AD 30,828
`GetSystemTimeAsFileTime()`	100 ns

Programlama dilleri ve uygulamaları

<table> <thead> <tr class="header"> <th>Dil / Uygulama</th> <th>İşlev veya değişken</th> <th>Çözüm</th> <th><a href="Çağ" title="wikilink">Çağ</a> veya aralık</th> </tr> </thead> <tbody> <tr class="odd"> <td><a href="Ada_(programlama_dili)" title="wikilink">Ada</a></td> <td><code>Ada.Calendar.Clock</code></td> <td>100 μs to 20 ms (*)</td> <td>1 Ocak 1901 - 31 Aralık 2099 (*)</td> </tr> <tr class="even"> <td><a href="AWK" title="wikilink">AWK</a></td> <td><code>systime()</code></td> <td>1 s</td> <td>(*)</td> </tr> <tr class="odd"> <td><a href="BASIC" title="wikilink">BASIC</a>, <a href="True_BASIC" title="wikilink">True BASIC</a></td> <td><code>DATE</code>, <code>DATE$</code> <code>TIME</code>, <code>TIME$</code></td> <td>1 s</td> <td>(*)</td> </tr> <tr class="even"> <td><a href="Business_BASIC" title="wikilink">Business BASIC</a></td> <td><code>DAY</code>, <code>TIM</code></td> <td>0.1 s</td> <td>(*)</td> </tr> <tr class="odd"> <td><a href="C_(programlama_dili)" title="wikilink">C</a> (see <a href="C_date_and_time_functions" title="wikilink">C date and time functions</a>)</td> <td><a href="time()" title="wikilink"><code>time()</code></a></td> <td>1 s (*)<a href="#fn1" class="footnote-ref" id="fnref1" role="doc-noteref">1</a></td> <td>(*)<a href="#fn2" class="footnote-ref" id="fnref2" role="doc-noteref">2</a></td> </tr> <tr class="even"> <td><a href="C++" title="wikilink">C++</a></td> <td><code>std::time()</code> <code>std::chrono::system_clock::now()</code></td> <td>1 s (*)<a href="#fn3" class="footnote-ref" id="fnref3" role="doc-noteref">3</a> 1 ns (C++11, OS dependent)</td> <td>(*)<a href="#fn4" class="footnote-ref" id="fnref4" role="doc-noteref">4</a></td> </tr> <tr class="odd"> <td><a href="C_Sharp" title="wikilink">C#</a> (<a href="Microsoft" title="wikilink">Microsoft</a>)</td> <td><code>System.DateTime.Now</code><a href="#fn5" class="footnote-ref" id="fnref5" role="doc-noteref">5</a> <code>System.DateTime.UtcNow</code><a href="#fn6" class="footnote-ref" id="fnref6" role="doc-noteref">6</a></td> <td>100 ns<a href="#fn7" class="footnote-ref" id="fnref7" role="doc-noteref">7</a></td> <td>1 Ocak 0001 - 31 Aralık 9999</td> </tr> <tr class="even"> <td><a href="CICS" title="wikilink">CICS</a> (<a href="IBM" title="wikilink">IBM</a>)</td> <td><code>ASKTIME</code></td> <td>1 ms</td> <td>1 Ocak 1900</td> </tr> <tr class="odd"> <td><a href="COBOL" title="wikilink">COBOL</a></td> <td><code>FUNCTION CURRENT-DATE</code></td> <td>1 s</td> <td>1 Ocak 1601</td> </tr> <tr class="even"> <td><a href="Common_Lisp" title="wikilink">Common Lisp</a></td> <td><code>(get-universal-time)</code></td> <td>1 s</td> <td>1 Ocak 1900</td> </tr> <tr class="odd"> <td><a href="Borland_Delphi" title="wikilink">Delphi</a> (<a href="Borland" title="wikilink">Borland</a>)</td> <td><code>date</code> <code>time</code></td> <td>1 ms (kayan nokta)</td> <td>1 Ocak 1900</td> </tr> <tr class="even"> <td><a href="Embarcadero_Delphi" title="wikilink">Delphi</a> (<a href="Embarcadero_Technologies" title="wikilink">Embarcadero Technologies</a>)<a href="#fn8" class="footnote-ref" id="fnref8" role="doc-noteref">8</a></td> <td><code>System.SysUtils.Time</code><a href="#fn9" class="footnote-ref" id="fnref9" role="doc-noteref">9</a></td> <td>1 ms</td> <td>0/0/0000 0:0:0:000 to 12/31/9999 23:59:59:999 [sic]</td> </tr> <tr class="odd"> <td><code>System.SysUtils.GetTime</code><a href="#fn10" class="footnote-ref" id="fnref10" role="doc-noteref">10</a> (alias for <code>System.SysUtils.Time</code>)</td> <td></td> <td></td> <td></td> </tr> <tr class="even"> <td><code>System.SysUtils.Date</code><a href="#fn11" class="footnote-ref" id="fnref11" role="doc-noteref">11</a></td> <td>0/0/00000:0:0:000 - 12/31/9999 0:0:0:000 [sic]</td> <td></td> <td></td> </tr> <tr class="odd"> <td><code>System.DateUtils.Today</code><a href="#fn12" class="footnote-ref" id="fnref12" role="doc-noteref">12</a></td> <td></td> <td></td> <td></td> </tr> <tr class="even"> <td><code>System.DateUtils.Tomorrow</code><a href="#fn13" class="footnote-ref" id="fnref13" role="doc-noteref">13</a></td> <td></td> <td></td> <td></td> </tr> <tr class="odd"> <td><code>System.DateUtils.Yesterday</code><a href="#fn14" class="footnote-ref" id="fnref14" role="doc-noteref">14</a></td> <td></td> <td></td> <td></td> </tr> <tr class="even"> <td><code>System.SysUtils.Now</code><a href="#fn15" class="footnote-ref" id="fnref15" role="doc-noteref">15</a></td> <td>1 s</td> <td>0/0/00000:0:0:000 - 12/31/9999 23:59:59:000 [sic]</td> <td></td> </tr> <tr class="odd"> <td><code>System.SysUtils.DayOfWeek</code><a href="#fn16" class="footnote-ref" id="fnref16" role="doc-noteref">16</a></td> <td>1 gün</td> <td>1 to 7</td> <td></td> </tr> <tr class="even"> <td><code>System.SysUtils.CurrentYear</code><a href="#fn17" class="footnote-ref" id="fnref17" role="doc-noteref">17</a></td> <td>1 yıl</td> <td>(*)</td> <td></td> </tr> <tr class="odd"> <td><a href="Emacs_Lisp" title="wikilink">Emacs Lisp</a></td> <td><code>(current-time)</code></td> <td>1 μs (*)</td> <td>1 Ocak 1970</td> </tr> <tr class="even"> <td><a href="Erlang_(programming_language)" title="wikilink">Erlang</a> (<a href="Ericsson" title="wikilink">Ericsson</a>)</td> <td><a href="http://erlang.org/doc/man/erlang.html#system_time-0"><code>erlang:system_time()</code></a>, <a href="http://erlang.org/doc/man/os.html#system_time-0"><code>os:system_time()</code></a><a href="#fn18" class="footnote-ref" id="fnref18" role="doc-noteref">18</a></td> <td><a href="Operating_system" title="wikilink">OS</a> bağımlı, e.g. on <a href="Linux" title="wikilink">Linux</a> 1ns<a href="#fn19" class="footnote-ref" id="fnref19" role="doc-noteref">19</a></td> <td>1 Ocak 1970<a href="#fn20" class="footnote-ref" id="fnref20" role="doc-noteref">20</a></td> </tr> <tr class="odd"> <td><a href="Microsoft_Excel" title="wikilink">Excel</a> (<a href="Microsoft" title="wikilink">Microsoft</a>)</td> <td><code>date()</code></td> <td>?</td> <td>0 Ocak 1900<a href="#fn21" class="footnote-ref" id="fnref21" role="doc-noteref">21</a></td> </tr> <tr class="even"> <td><a href="Fortran" title="wikilink">Fortran</a></td> <td><code>DATE_AND_TIME</code> <code>SYSTEM_CLOCK</code></td> <td>(*)<a href="#fn22" class="footnote-ref" id="fnref22" role="doc-noteref">22</a> <a href="#fn23" class="footnote-ref" id="fnref23" role="doc-noteref">23</a></td> <td>1 Ocak 1970</td> </tr> <tr class="odd"> <td><code>CPU_TIME</code></td> <td>1 μs</td> <td></td> <td></td> </tr> <tr class="even"> <td><a href="Go_(programlama_dili)" title="wikilink">Go</a></td> <td><code>time.Now()</code></td> <td>1 ns</td> <td>1 Ocak 0001</td> </tr> <tr class="odd"> <td><a href="Haskell_(programming_language)" title="wikilink">Haskell</a></td> <td><code>Time.getClockTime</code></td> <td>1 ps (*)</td> <td>1 Ocak 1970 (*)</td> </tr> <tr class="even"> <td><code>Data.Time.getCurrentTime</code></td> <td>1 ps (*)</td> <td>17 Kasım 1858 (*)</td> <td></td> </tr> <tr class="odd"> <td><a href="Java_(Sun)" title="wikilink">Java</a> (<a href="Sun_Microsystems" title="wikilink">Sun</a>)</td> <td><code>java.util.Date()</code> <code>System.currentTimeMillis()</code></td> <td>1 ms</td> <td>1 Ocak 1970</td> </tr> <tr class="even"> <td><code>System.nanoTime()</code><a href="#fn24" class="footnote-ref" id="fnref24" role="doc-noteref">24</a></td> <td>1 ns</td> <td>keyfi<a href="#fn25" class="footnote-ref" id="fnref25" role="doc-noteref">25</a></td> <td></td> </tr> <tr class="odd"> <td><code>Clock.systemUTC()</code><a href="#fn26" class="footnote-ref" id="fnref26" role="doc-noteref">26</a></td> <td>1 ns</td> <td>keyfi<a href="#fn27" class="footnote-ref" id="fnref27" role="doc-noteref">27</a></td> <td></td> </tr> <tr class="even"> <td><a href="JavaScript" title="wikilink">JavaScript</a></td> <td><code>(new Date()).getTime()</code> <code>Date.now()</code></td> <td>1 ms</td> <td>1 Ocak 1970</td> </tr> <tr class="odd"> <td><a href="Matlab" title="wikilink">Matlab</a></td> <td><code>now</code></td> <td>1 s</td> <td>0 Ocak 0000<a href="#fn28" class="footnote-ref" id="fnref28" role="doc-noteref">28</a></td> </tr> <tr class="even"> <td><a href="MUMPS" title="wikilink">MUMPS</a></td> <td><code>$H</code> (short for <a href="Horology" title="wikilink"><code>$HOROLOG</code></a>)</td> <td>1 s</td> <td>31 Aralık 1840</td> </tr> <tr class="odd"> <td><a href="LabVIEW" title="wikilink">LabVIEW</a></td> <td><code>Tick Count</code></td> <td>1 ms</td> <td>00:00:00.000 1 Ocak 1904</td> </tr> <tr class="even"> <td><code>Get Date/Time in Seconds</code></td> <td>1 ms</td> <td>00:00:00.000 1 Ocak 1904</td> <td></td> </tr> <tr class="odd"> <td><a href="Objective-C" title="wikilink">Objective-C</a></td> <td><code>[NSDate timeIntervalSinceReferenceDate]</code></td> <td>< 1 ms<a href="#fn29" class="footnote-ref" id="fnref29" role="doc-noteref">29</a></td> <td>1 Ocak 2001 ±10,000 Yıl<a href="#fn30" class="footnote-ref" id="fnref30" role="doc-noteref">30</a></td> </tr> <tr class="even"> <td><a href="OCaml" title="wikilink">OCaml</a></td> <td><code>Unix.time()</code></td> <td>1 s</td> <td>1 Ocak 1970</td> </tr> <tr class="odd"> <td><code>Unix.gettimeofday()</code></td> <td>1 μs</td> <td></td> <td></td> </tr> <tr class="even"> <td><a href="Pascal_(programlama_dili)" title="wikilink">Extended Pascal</a></td> <td><code>GetTimeStamp()</code></td> <td>1 s</td> <td>(*)</td> </tr> <tr class="odd"> <td><a href="Turbo_Pascal" title="wikilink">Turbo Pascal</a></td> <td><code>GetTime()</code> <code>GetDate()</code></td> <td>10 ms</td> <td>(*)</td> </tr> <tr class="even"> <td><a href="Perl" title="wikilink">Perl</a></td> <td><code>time()</code></td> <td>1 s</td> <td>1 Ocak 1970</td> </tr> <tr class="odd"> <td><code>Time::HiRes::time</code><a href="#fn31" class="footnote-ref" id="fnref31" role="doc-noteref">31</a></td> <td>1 μs</td> <td></td> <td></td> </tr> <tr class="even"> <td><a href="PHP" title="wikilink">PHP</a></td> <td><code>time()</code> <code>mktime()</code></td> <td>1 s</td> <td>1 Ocak 1970</td> </tr> <tr class="odd"> <td><code>microtime()</code></td> <td>1 μs</td> <td></td> <td></td> </tr> <tr class="even"> <td><a href="Python" title="wikilink">Python</a></td> <td><code>datetime.now().timestamp()</code></td> <td>1 μs (*)</td> <td>1 Ocak 1970</td> </tr> <tr class="odd"> <td><a href="IBM_RPG" title="wikilink">RPG</a></td> <td><code>CURRENT(DATE)</code>, <code>%DATE</code> <code>CURRENT(TIME)</code>, <code>%TIME</code></td> <td>1 s</td> <td>1 Ocak 0001 - 31 Aralık 9999</td> </tr> <tr class="even"> <td><code>CURRENT(TIMESTAMP)</code>, <code>%TIMESTAMP</code></td> <td>1 μs</td> <td></td> <td></td> </tr> <tr class="odd"> <td><a href="Ruby_(programming_language)" title="wikilink">Ruby</a></td> <td><code>Time.now()</code><a href="#fn32" class="footnote-ref" id="fnref32" role="doc-noteref">32</a></td> <td>1 μs (*)</td> <td>1 Ocak 1970 (kadar 19 Ocak 2038 Ruby'den önce 1.9.2<a href="#fn33" class="footnote-ref" id="fnref33" role="doc-noteref">33</a>)</td> </tr> <tr class="even"> <td><a href="Smalltalk" title="wikilink">Smalltalk</a></td> <td><code>Time microsecondClock</code> </td> <td>1 s 1 μs 1 s </td> <td>1 Ocak 1901 (*)</td> </tr> <tr class="odd"> <td><code>Time totalSeconds</code> </td> <td></td> <td></td> <td></td> </tr> <tr class="even"> <td><code>SystemClock ticksNowSinceSystemClockEpoch</code> </td> <td></td> <td></td> <td></td> </tr> <tr class="odd"> <td><a href="SQL" title="wikilink">SQL</a></td> <td><code>CURDATE()</code> <code>CURTIME()</code> <code>GETDATE()</code> <code>NOW()</code> <code>SYSDATE()</code></td> <td>3 ms</td> <td>1 Ocak 1753 - 31 Aralık 9999 (*)</td> </tr> <tr class="even"> <td>60 s</td> <td>1 Ocak 1900 - 6 Haziran 2079</td> <td></td> <td></td> </tr> <tr class="odd"> <td><a href="Standard_ML" title="wikilink">Standard ML</a></td> <td><code>Time.now()</code></td> <td>1 μs (*)</td> <td>1 Ocak 1970 (*)</td> </tr> <tr class="even"> <td><a href="Tcl" title="wikilink">TCL</a></td> <td><code>[clock seconds]</code></td> <td>1 s</td> <td>1 Ocak 1970</td> </tr> <tr class="odd"> <td><code>[clock milliseconds]</code></td> <td>1 ms</td> <td></td> <td></td> </tr> <tr class="even"> <td><code>[clock microseconds]</code></td> <td>1 μs</td> <td></td> <td></td> </tr> <tr class="odd"> <td><code>[clock clicks]</code></td> <td>1 μs (*)</td> <td>(*)</td> <td></td> </tr> <tr class="even"> <td><a href="Windows_PowerShell" title="wikilink">Windows PowerShell</a></td> <td><code>Get-Date</code><a href="#fn34" class="footnote-ref" id="fnref34" role="doc-noteref">34</a><a href="#fn35" class="footnote-ref" id="fnref35" role="doc-noteref">35</a></td> <td>100 ns<a href="#fn36" class="footnote-ref" id="fnref36" role="doc-noteref">36</a></td> <td>1 Ocak 0001 - 31 Aralık 9999</td> </tr> <tr class="odd"> <td><code>[DateTime]::Now</code><a href="#fn37" class="footnote-ref" id="fnref37" role="doc-noteref">37</a> <code>[DateTime]::UtcNow</code><a href="#fn38" class="footnote-ref" id="fnref38" role="doc-noteref">38</a></td> <td></td> <td></td> <td></td> </tr> <tr class="even"> <td><a href="Visual_Basic_.NET" title="wikilink">Visual Basic .NET</a> (<a href="Microsoft" title="wikilink">Microsoft</a>)</td> <td><code>System.DateTime.Now</code><a href="#fn39" class="footnote-ref" id="fnref39" role="doc-noteref">39</a> <code>System.DateTime.UtcNow</code><a href="#fn40" class="footnote-ref" id="fnref40" role="doc-noteref">40</a></td> <td>100 ns<a href="#fn41" class="footnote-ref" id="fnref41" role="doc-noteref">41</a></td> <td>1 Ocak 0001 - 31 Aralık 9999</td> </tr> </tbody> </table> <section class="footnotes footnotes-end-of-document" role="doc-endnotes"> <hr /> <ol> <li id="fn1" role="doc-endnote">The <a href="C_standard_library" title="wikilink">C standard library</a> does not specify any specific resolution, epoch, range, or datatype for <a href="time_t" title="wikilink">system time values</a>. The C++ library encompasses the C library, so it uses the same system time implementation as C.<a href="#fnref1" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn2" role="doc-endnote"></li> <li id="fn3" role="doc-endnote"></li> <li id="fn4" role="doc-endnote"></li> <li id="fn5" role="doc-endnote"><a href="http://msdn.microsoft.com/en-us/library/system.datetime.now.aspx">"DateTime.Now Property"</a> in <a href="MSDN" title="wikilink">MSDN</a> (Microsoft, 2010) last updated July 2010.<a href="#fnref5" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn6" role="doc-endnote"><a href="http://msdn.microsoft.com/en-us/library/system.datetime.utcnow.aspx">"DateTime.UtcNow Property"</a> in MSDN (Microsoft, 2011)<a href="#fnref6" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn7" role="doc-endnote"><a href="http://msdn.microsoft.com/en-us/library/system.datetime.ticks.aspx">"DateTime.Ticks Property</a> in MSDN (Microsoft, 2010) last updated May 2010.<a href="#fnref7" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn8" role="doc-endnote"><a href="http://docwiki.embarcadero.com/RADStudio/XE4/en/Date_and_Time_Support">"Date and Time Support"</a> in Embarcadero Developer Network (Embarcadero Technologies, 2013)<a href="#fnref8" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn9" role="doc-endnote"><a href="http://docwiki.embarcadero.com/Libraries/XE4/en/System.SysUtils.Time">"System.SysUtils.Time"</a> in Embarcadero Developer Network (Embarcadero Technologies, 2013)<a href="#fnref9" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn10" role="doc-endnote"><a href="http://docwiki.embarcadero.com/Libraries/XE4/en/System.SysUtils.GetTime">"System.SysUtils.GetTime"</a> in Embarcadero Developer Network (Embarcadero Technologies, 2013)<a href="#fnref10" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn11" role="doc-endnote"><a href="http://docwiki.embarcadero.com/Libraries/XE4/en/System.SysUtils.Date">"System.SysUtils.Date"</a> in Embarcadero Developer Network (Embarcadero Technologies, 2013)<a href="#fnref11" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn12" role="doc-endnote"><a href="http://docwiki.embarcadero.com/Libraries/XE4/en/System.DateUtils.Today">"System.DateUtils.Today"</a> in Embarcadero Developer Network (Embarcadero Technologies, 2013)<a href="#fnref12" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn13" role="doc-endnote"><a href="http://docwiki.embarcadero.com/Libraries/XE4/en/System.DateUtils.Tomorrow">"System.DateUtils.Tomorrow"</a> in Embarcadero Developer Network (Embarcadero Technologies, 2013)<a href="#fnref13" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn14" role="doc-endnote"><a href="http://docwiki.embarcadero.com/Libraries/XE4/en/System.DateUtils.Yesterday">"System.DateUtils.Yesterday"</a> in Embarcadero Developer Network (Embarcadero Technologies, 2013)<a href="#fnref14" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn15" role="doc-endnote"><a href="http://docwiki.embarcadero.com/Libraries/XE4/en/System.SysUtils.Now">"System.SysUtils.Now"</a> in Embarcadero Developer Network (Embarcadero Technologies, 2013)<a href="#fnref15" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn16" role="doc-endnote"><a href="http://docwiki.embarcadero.com/Libraries/XE4/en/System.SysUtils.DayOfWeek">"System.SysUtils.DayOfWeek"</a> in Embarcadero Developer Network (Embarcadero Technologies, 2013)<a href="#fnref16" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn17" role="doc-endnote"><a href="http://docwiki.embarcadero.com/Libraries/XE4/en/System.SysUtils.CurrentYear">"System.SysUtils.CurrentYear"</a> in Embarcadero Developer Network (Embarcadero Technologies, 2013)<a href="#fnref17" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn18" role="doc-endnote"><a href="#fnref18" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn19" role="doc-endnote"></li> <li id="fn20" role="doc-endnote"></li> <li id="fn21" role="doc-endnote">"In the Microsoft Office Spreadsheet Component, the value 0 evaluates to the date December 30, 1899 and the value 1 evaluates to December 31, 1899. ... In Excel, the value 0 evaluates to January 0, 1900 and the value 1 evaluates to January 1, 1900." <a href="http://support.microsoft.com/kb/205719">XL2000: Early Dates on Office Spreadsheet Component Differ from Excel</a> in (Microsoft Support, 2003).<a href="#fnref21" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn22" role="doc-endnote"><a href="http://software.intel.com/sites/products/documentation/hpc/compilerpro/en-us/fortran/lin/compiler_f/lref_for/source_files/rfsystmc.htm">"SYSTEM_CLOCK"</a> , documentation for FORTRAN compiler, Intel Corp., accessed 27 October 2011.<a href="#fnref22" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn23" role="doc-endnote"><a href="https://gcc.gnu.org/onlinedocs/gfortran/SYSTEM_005fCLOCK.html">SYSTEM_CLOCK — Time function"</a> in The GNU Fortran Compiler (Free Software Foundation) accessed 27 October 2011.<a href="#fnref23" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn24" role="doc-endnote">[<a href="http://java.sun.com/javase/6/docs/api/java/lang/System.html#nanoTime">http://java.sun.com/javase/6/docs/api/java/lang/System.html#nanoTime</a>() System.nanoTime() method] in Java Platform, Standard Edition 6: API Specification (Oracle, 2011) accessed 27 October 2011.<a href="#fnref24" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn25" role="doc-endnote"></li> <li id="fn26" role="doc-endnote"><a href="https://docs.oracle.com/javase/8/docs/api/java/time/Clock.html#systemUTC--">Clock.systemUTC() and other methods</a> in Java Platform, Standard Edition 8: API Specification (Oracle, 2014) accessed 15 January 2015.<a href="#fnref26" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn27" role="doc-endnote"><a href="https://docs.oracle.com/javase/8/docs/api/java/time/Instant.html">JSR-310 Java Time System</a> in Java Platform, Standard Edition 8: API Specification (Oracle, 2014) accessed 15 January 2015.<a href="#fnref27" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn28" role="doc-endnote"><a href="http://www.mathworks.com/help/matlab/ref/datenum.html">1</a> Matlab Help<a href="#fnref28" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn29" role="doc-endnote"><a href="http://developer.apple.com/mac/library/documentation/Cocoa/Reference/Foundation/Miscellaneous/Foundation_DataTypes/Reference/reference.html#apple_ref/c/tdef/NSTimeInterval">"Foundation Data Types Reference"</a> in Mac OS X Developer Library (Apple, 2011) last modified 6 July 2011, section NSTimeInterval.<a href="#fnref29" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn30" role="doc-endnote"></li> <li id="fn31" role="doc-endnote">Douglas Wegscheild, R. Schertler, and Jarkko Hietaniemi, [<a href="https://metacpan.org/module/Time">https://metacpan.org/module/Time</a>::HiRes "Time::HiRes"] (CPAN Comprehensive Perl Archive Network, 2011) accessed 27 October 2011.<a href="#fnref31" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn32" role="doc-endnote"><a href="http://www.ruby-doc.org/core/classes/Time.html">Time class</a> in Ruby-Doc.org: Help and documentation for the Ruby programming language (Scottsdale, AZ: James Britt and Neurogami) accessed 27 October 2011.<a href="#fnref32" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn33" role="doc-endnote"><a href="http://www.ruby-lang.org/en/news/2010/08/18/ruby-1-9.2-released/">Ruby 1.9.2 Release Notes</a> in Ruby-Doc.org: Help and documentation for the Ruby programming language (Scottsdale, AZ: James Britt and Neurogami) accessed 27 October 2011.<a href="#fnref33" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn34" role="doc-endnote"><a href="#fnref34" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn35" role="doc-endnote"><a href="#fnref35" class="footnote-back" role="doc-backlink">↩︎</a></li> <li id="fn36" role="doc-endnote"></li> <li id="fn37" role="doc-endnote"></li> <li id="fn38" role="doc-endnote"></li> <li id="fn39" role="doc-endnote"></li> <li id="fn40" role="doc-endnote"></li> <li id="fn41" role="doc-endnote"></li> </ol> </section>