136 lines
3.9 KiB
HTML
136 lines
3.9 KiB
HTML
|
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
|
<HTML><HEAD><TITLE>Man page of ADJTIME_CONFIG</TITLE>
|
|
</HEAD><BODY>
|
|
<H1>ADJTIME_CONFIG</H1>
|
|
Section: File Formats (5)<BR>Updated: August 2018<BR><A HREF="#index">Index</A>
|
|
<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
|
|
|
|
<A NAME="lbAB"> </A>
|
|
<H2>NAME</H2>
|
|
|
|
adjtime - information about hardware clock setting and drift factor
|
|
<A NAME="lbAC"> </A>
|
|
<H2>SYNOPSIS</H2>
|
|
|
|
<I>/etc/adjtime</I>
|
|
|
|
<A NAME="lbAD"> </A>
|
|
<H2>DESCRIPTION</H2>
|
|
|
|
The file
|
|
<B>/etc/adjtime</B>
|
|
|
|
contains descriptive information about the hardware mode clock setting and clock drift factor.
|
|
The file is read and write by hwclock; and read by programs like rtcwake to get RTC time mode.
|
|
<P>
|
|
|
|
The file is usually located in /etc, but tools like
|
|
<B><A HREF="/cgi-bin/man/man2html?8+hwclock">hwclock</A></B>(8)
|
|
|
|
or
|
|
<B><A HREF="/cgi-bin/man/man2html?8+rtcwake">rtcwake</A></B>(8)
|
|
|
|
allow to use alternative location by command line options if write access to
|
|
/etc is unwanted. The default clock mode is "UTC" if the file is missing.
|
|
<P>
|
|
|
|
The Hardware Clock is usually not very accurate. However, much of its inaccuracy is completely predictable - it gains
|
|
or loses the same amount of time every day. This is called systematic drift. The util hwclock keeps the file /etc/adjtime,
|
|
that keeps some historical information.
|
|
For more details see "<B>The Adjust Function</B>" and "<B>The Adjtime File</B>" sections from
|
|
<B><A HREF="/cgi-bin/man/man2html?8+hwckock">hwckock</A></B>(8)
|
|
|
|
man page.
|
|
<P>
|
|
|
|
<P>
|
|
The format of the adjtime file is, in ASCII.
|
|
<P>
|
|
<A NAME="lbAE"> </A>
|
|
<H3>First line</H3>
|
|
|
|
Three numbers, separated by blanks:
|
|
<DL COMPACT>
|
|
<DT id="1"><B>drift factor</B>
|
|
|
|
<DD>
|
|
the systematic drift rate in seconds per day (floating point decimal)
|
|
<DT id="2"><B>last adjust time</B>
|
|
|
|
<DD>
|
|
the resulting number of seconds since 1969 UTC of most recent adjustment or calibration (decimal integer)
|
|
<DT id="3"><B>adjustment status</B>
|
|
|
|
<DD>
|
|
zero (for compatibility with <A HREF="/cgi-bin/man/man2html?8+clock">clock</A>(8)) as a decimal integer.
|
|
<P>
|
|
</DL>
|
|
<A NAME="lbAF"> </A>
|
|
<H3>Second line</H3>
|
|
|
|
<DL COMPACT>
|
|
<DT id="4"><B>last calibration time</B>
|
|
|
|
<DD>
|
|
The resulting number of seconds since 1969 UTC of most recent calibration.
|
|
Zero if there has been no calibration yet or it is known that any previous
|
|
calibration is moot (for example, because the Hardware Clock has been found,
|
|
since that calibration, not to contain a valid time). This is a decimal
|
|
integer.
|
|
<P>
|
|
</DL>
|
|
<A NAME="lbAG"> </A>
|
|
<H3>Third line</H3>
|
|
|
|
<DL COMPACT>
|
|
<DT id="5"><B>clock mode</B>
|
|
|
|
<DD>
|
|
Supported values are "UTC" or "LOCAL". Tells whether the Hardware Clock is set
|
|
to Coordinated Universal Time or local time. You can always override this
|
|
value with options on the hwclock command line.
|
|
<P>
|
|
</DL>
|
|
<A NAME="lbAH"> </A>
|
|
<H2>FILES</H2>
|
|
|
|
<I>/etc/adjtime</I>
|
|
|
|
<A NAME="lbAI"> </A>
|
|
<H2>SEE ALSO</H2>
|
|
|
|
<B><A HREF="/cgi-bin/man/man2html?8+hwclock">hwclock</A></B>(8),
|
|
|
|
<B><A HREF="/cgi-bin/man/man2html?8+rtcwake">rtcwake</A></B>(8)
|
|
|
|
<A NAME="lbAJ"> </A>
|
|
<H2>AVAILABILITY</H2>
|
|
|
|
This man page is part of the util-linux package and is available from
|
|
<A HREF="https://www.kernel.org/pub/linux/utils/util-linux/.">https://www.kernel.org/pub/linux/utils/util-linux/.</A>
|
|
<P>
|
|
|
|
<HR>
|
|
<A NAME="index"> </A><H2>Index</H2>
|
|
<DL>
|
|
<DT id="6"><A HREF="#lbAB">NAME</A><DD>
|
|
<DT id="7"><A HREF="#lbAC">SYNOPSIS</A><DD>
|
|
<DT id="8"><A HREF="#lbAD">DESCRIPTION</A><DD>
|
|
<DL>
|
|
<DT id="9"><A HREF="#lbAE">First line</A><DD>
|
|
<DT id="10"><A HREF="#lbAF">Second line</A><DD>
|
|
<DT id="11"><A HREF="#lbAG">Third line</A><DD>
|
|
</DL>
|
|
<DT id="12"><A HREF="#lbAH">FILES</A><DD>
|
|
<DT id="13"><A HREF="#lbAI">SEE ALSO</A><DD>
|
|
<DT id="14"><A HREF="#lbAJ">AVAILABILITY</A><DD>
|
|
</DL>
|
|
<HR>
|
|
This document was created by
|
|
<A HREF="/cgi-bin/man/man2html">man2html</A>,
|
|
using the manual pages.<BR>
|
|
Time: 00:06:02 GMT, March 31, 2021
|
|
</BODY>
|
|
</HTML>
|