Date: Mon, 01 Oct 2001 06:43:42 -0700 From: Dima Dorfman <dima@trit.org> To: Tom Hukins <tom@FreeBSD.org> Cc: setantae <setantae@submonkey.net>, "Bruce A. Mah" <bmah@FreeBSD.ORG>, Wouter Van Hemel <wvhemel@vub.ac.be>, doc@freebsd.org Subject: Re: Please review: NTP section for Handbook Message-ID: <20011001134347.EF4D93E01@bazooka.trit.org> In-Reply-To: <20011001140336.A29053@eborcom.com>; from tom@FreeBSD.org on "Mon, 1 Oct 2001 14:03:36 %2B0100"
next in thread | previous in thread | raw e-mail | index | archive | help
Tom Hukins <tom@FreeBSD.org> wrote: > Thanks for the comments - the feedback I received has been really > helpful. > > I've updated the document at > http://people.FreeBSD.org/~tom/tmp/ntp.sgml to incorporate all the > suggestions I received. Attached is a patch that fixes some more minor problems. Most of the changes are mechanical, such as &man.ntp.8; -> &man.ntpd.8; and other such typos. The only non-mechanical change is about the driftfile. Your explanation was a ways off; it does not countain "information about previous responses from the NTP servers you are using". In fact, I think ntpd can compute the drift without an external time source. Thanks for the great work! --- ntp.sgml~ Mon Oct 1 13:10:51 2001 +++ ntp.sgml Mon Oct 1 13:38:10 2001 @@ -1,3 +1,4 @@ + <!-- XXX Second person prevalent. --> <sect1 id="ntp"> <sect1info> <authorgroup> @@ -29,7 +30,7 @@ <indexterm><primary>ntpd</primary></indexterm> <para>FreeBSD ships with the &man.ntpd.8; NTP server which can be used to query other NTP servers to set the clock on your - machine.</para> + machine, and/or provide time service to others.</para> </sect2> <sect2> @@ -64,15 +65,17 @@ machine boots up, you can use &man.ntpdate.8;. This may be appropriate for some desktop machines which are frequently rebooted and only require infrequent synchronization, but - most machines should run &man.ntp.8;.</para> + most machines should run &man.ntpd.8;.</para> + <!-- XXX should wrap this paragraph. --> + <!-- XXX &man.ntp.8; -> &man.ntpd.8; --> <para>Using &man.ntpdate.8; at boot time is also a good idea for machines that run &man.ntp.8;. &man.ntp.8; changes the clock gradually, whereas &man.ntpdate.8; sets the clock, no matter how great the difference between a machine's current clock setting and the correct time.</para> <para>To enable &man.ntpdate.8; at boot time, add <programlisting>ntpdate_enable="YES"</programlisting> to <filename>/etc/rc.conf</filename>. You will also need to specify all servers you wish to synchronize with and any - flags to be passed to &man.nptdate.8; in + flags to be passed to &man.ntpdate.8; in <varname>ntpdate_flags</varname>.</para> </sect3> @@ -82,7 +85,8 @@ <para>NTP is configured by the <filename>/etc/ntp.conf</filename> file in the format - described in &man.ntp.conf.5; as follows:</para> + described in &man.ntp.conf.5;. The simplest form looks + like this:</para> <programlisting>server ntp.isp.example.com prefer server timeserver.foobardomain.org @@ -90,6 +94,12 @@ driftfile /var/db/ntp.drift</programlisting> + <!-- XXX The 'prefer' keyword is a lot more complicated than this + paragraph makes it out to be. Specifically, while the prefer + peer can be discarded as a falseticker, it will never be + discarded by the clustering algorithm. It's mostly designed + to be used with reference clocks. --> + <para>The <literal>server</literal> option specifies which servers are to be used, with one server listed on each line. If a server is specified with the <literal>prefer</literal> @@ -99,11 +109,12 @@ server because it is on the same network as your machine or more reliable.</para> - <para>The <literal>driftfile</literal> option specifies which - file is used to store information about previous responses - from the NTP servers you are using. This file contains - internal information for NTP. It should not be modified by - any other process.</para> + <para>The <literal>driftfile</literal> option specifies which file + is used to store the system clock's frequency offset. + &man.ntpd.8; uses this to automatically compensate for the + clock's natural drift, allowing it to maintain a reasonably + correct setting even if it is cut off from all external time + sources for a period of time.</para> </sect3> <sect3> @@ -130,7 +141,7 @@ <para><filename>/etc/ntp.conf</filename> can contain multiple <literal>restrict</literal> options. For more details, see - the <literal>Access Control Support</literal> of + the <literal>Access Control Support</literal> subsection of &man.ntp.conf.5;.</para> </sect3> </sect2> @@ -181,7 +192,6 @@ preventing NTP from from functioning since replies never reach your machine.</para> </note> - </sect2> <sect2> @@ -190,6 +200,5 @@ <para>Documentation for the NTP server can be found in <filename>/usr/share/doc/ntp/</filename> in HTML format.</para> - </sect2> </sect1> To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-doc" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20011001134347.EF4D93E01>