<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> <HTML ><HEAD ><TITLE >Managing Accurate Date and Time</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.7"><LINK REL="NEXT" TITLE="Why do We Need a Precise Clock?" HREF="why.html"></HEAD ><BODY CLASS="article" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="ARTICLE" ><DIV CLASS="TITLEPAGE" ><H1 CLASS="title" ><A NAME="AEN2" ></A >Managing Accurate Date and Time</H1 ><DIV CLASS="authorgroup" ><A NAME="AEN7" ></A ><H3 CLASS="author" ><A NAME="AEN8" >Avi Alkalay</A ></H3 ><P CLASS="othercredit" ><B >Brad Knowles - </B ><SPAN CLASS="contrib" >Suggestion to use pool.ntp.org and NTP's stratum 2 public time servers</SPAN ></P ><P CLASS="othercredit" ><B >Kent Borg - </B ><SPAN CLASS="contrib" >Suggestion to use ntpq instead of ntpdc</SPAN ></P ><P CLASS="othercredit" ><B >Yura Moron - </B ><SPAN CLASS="contrib" >Good explanations on ntpq and ntpdc info</SPAN ></P ><P CLASS="othercredit" ><B >Takeo Nakano - </B ></P ><P CLASS="othercredit" ><B >SHAKI - </B ></P ><P CLASS="othercredit" ><B >Mihaly Gyulai - </B ></P ><P CLASS="othercredit" ><B >Philippe Wautelet - </B ></P ><P CLASS="othercredit" ><B >Kemal Ökmen - </B ></P ></DIV ><P CLASS="copyright" >Copyright © 2002,2003,2004,2005 Avi Alkalay</P ><P CLASS="pubdate" >2005-11-18<BR></P ><DIV CLASS="revhistory" ><TABLE WIDTH="100%" BORDER="0" ><TR ><TH ALIGN="LEFT" VALIGN="TOP" COLSPAN="3" ><B >Revision History</B ></TH ></TR ><TR ><TD ALIGN="LEFT" >Revision 2005-11-18</TD ><TD ALIGN="LEFT" >18 Nov 2005</TD ><TD ALIGN="LEFT" >Revised by: Avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Included link to turkish translation</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 2005-10-12</TD ><TD ALIGN="LEFT" >12 Oct 2005</TD ><TD ALIGN="LEFT" >Revised by: Avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >The Brazil zic file is now external and updated</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 2005-05-03</TD ><TD ALIGN="LEFT" >03 May 2005</TD ><TD ALIGN="LEFT" >Revised by: Avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Included link to french translation</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 1.0.8</TD ><TD ALIGN="LEFT" >2004-10-29</TD ><TD ALIGN="LEFT" >Revised by: Mihaly Gyulai</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Hungarian translation, the chorny section and the very first section</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 1.0.7</TD ><TD ALIGN="LEFT" >9 Jul 2004</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Disclaimer near to license, to let people know they can translate without asking permission.Small fixes in some phrases.</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 1.0.6</TD ><TD ALIGN="LEFT" >25 Feb 2004</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Included credits and link to russian translation.</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 1.0.5</TD ><TD ALIGN="LEFT" >05 Jul 2003</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Changed public time servers list URL. Added pool.ntp.org.</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 1.0.4</TD ><TD ALIGN="LEFT" >21 Dec 2002</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Added japanese translation link and credits.</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 1.0.3</TD ><TD ALIGN="LEFT" >24 Aug 2002</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Fixed wrong screen and programlisting widths.</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 1.0.2</TD ><TD ALIGN="LEFT" >04 Aug 2002</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Link to public time servers page.</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 1.0.1</TD ><TD ALIGN="LEFT" >07 May 2002</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Final XML conversion. Files reorganization.</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 1.0</TD ><TD ALIGN="LEFT" >28 Apr 2002</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Finalized image.</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 0.8</TD ><TD ALIGN="LEFT" >27 Apr 2002</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Switched from ntpdc example to ntpq, based on contributions.</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 0.8.1</TD ><TD ALIGN="LEFT" >20 Apr 2002</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Improved graphic. Links to other doc locations.</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 0.8</TD ><TD ALIGN="LEFT" >14 Apr 2002</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Beter tunning of NTP graphic.</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 0.76</TD ><TD ALIGN="LEFT" >13 Apr 2002</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Inclusion of architecture graphic.</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 0.75</TD ><TD ALIGN="LEFT" >10 Apr 2002</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Spell checked. Using DocBook XSLT 1.50.</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 0.65</TD ><TD ALIGN="LEFT" >31 Mar 2002</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Upgraded to XML 4.1.2 DocBook format</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 0.6</TD ><TD ALIGN="LEFT" >29 Mar 2002</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >Finished timezone mechanism on Linux. Created appendix. Now only drawings are needed.</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 0.4</TD ><TD ALIGN="LEFT" >24 Mar 2002</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >All skeleton defined. All command examples written.</TD ></TR ><TR ><TD ALIGN="LEFT" >Revision 0.2</TD ><TD ALIGN="LEFT" >19 Mar 2002</TD ><TD ALIGN="LEFT" >Revised by: avi</TD ></TR ><TR ><TD ALIGN="LEFT" COLSPAN="3" >First DocBook version</TD ></TR ></TABLE ></DIV ><HR></DIV ><DIV CLASS="TOC" ><DL ><DT ><B >Table of Contents</B ></DT ><DT >1. <A HREF="why.html" >Why do We Need a Precise Clock?</A ></DT ><DD ><DL ><DT >1.1. <A HREF="why.html#why.pcclock" >On What Factors Does the Hardware-Clock Depend?</A ></DT ></DL ></DD ><DT >2. <A HREF="time.html" >Computer Global Date and Time Concept</A ></DT ><DT >3. <A HREF="tz.html" >What are Time Zones?</A ></DT ><DD ><DL ><DT >3.1. <A HREF="tz.html#tz.dst" >Daylight Savings Time</A ></DT ><DT >3.2. <A HREF="tz.html#tz.examples" >Time Zones Examples</A ></DT ><DT >3.3. <A HREF="tz.html#tz.linux" >Time Zone Mechanism on Linux</A ></DT ></DL ></DD ><DT >4. <A HREF="set.html" >The Correct Settings for Your Linux Box</A ></DT ><DD ><DL ><DT >4.1. <A HREF="set.html#set.tz" >Setting Time Zone</A ></DT ><DT >4.2. <A HREF="set.html#set.hwclock" >Setting the Hardware Clock</A ></DT ></DL ></DD ><DT >5. <A HREF="ntp.html" >Accurate Global Time Synchronization</A ></DT ><DD ><DL ><DT >5.1. <A HREF="ntp.html#ntp.ntp" ><SPAN CLASS="acronym" >NTP</SPAN >: The Network Time Protocol</A ></DT ><DT >5.2. <A HREF="ntp.html#ntp.arch" >Building a Simple Time Synchronization Architecture</A ></DT ><DT >5.3. <A HREF="ntp.html#ntp.configs" ><SPAN CLASS="acronym" >NTP</SPAN > Configurations</A ></DT ><DT >5.4. <A HREF="ntp.html#ntp.watch" >Watching Your Box Synchronizing</A ></DT ><DT >5.5. <A HREF="ntp.html#ntp.boot" >Configure to Automatically Run <SPAN CLASS="acronym" >NTP</SPAN > at Boot</A ></DT ></DL ></DD ><DT >6. <A HREF="ntp.chrony.html" >Precise Time with the <B CLASS="command" >chrony</B > Program</A ></DT ><DD ><DL ><DT >6.1. <A HREF="ntp.chrony.html#ntp.chrony.diff" >How <B CLASS="command" >chrony</B > Differs from the <B CLASS="command" >ntp</B > Suite?</A ></DT ><DT >6.2. <A HREF="ntp.chrony.html#ntp.chrony.how" >How to Use <B CLASS="command" >chrony</B >?</A ></DT ></DL ></DD ><DT >A. <A HREF="about.html" >About this Document</A ></DT ></DL ></DIV ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" > </TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" > </TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="why.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" > </TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" > </TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >Why do We Need a Precise Clock?</TD ></TR ></TABLE ></DIV ></BODY ></HTML >