8884034104
This is a verbatim copy of the files at that stage of the repository that was built from the CVS import. It allows future development to see a bit of recent history, but without carrying around the baggage going back to 1997. If that is really required, git grafts can be used.
65 lines
2.6 KiB
Groff
65 lines
2.6 KiB
Groff
.TH CHRONY 1 "August 10, 2001" chrony "User's Manual"
|
|
.SH NAME
|
|
chrony \- programs for keeping computer clocks accurate
|
|
|
|
.SH SYNOPSIS
|
|
\fBchronyc\fR [\fIOPTIONS\fR]
|
|
|
|
\fBchronyd\fR [\fIOPTIONS\fR]
|
|
|
|
.SH DESCRIPTION
|
|
\fBchrony\fR is a pair of programs for keeping computer clocks accurate.
|
|
\fIchronyd\fR is a background (daemon) program and \fIchronyc\fR is a
|
|
command-line interface to it. Time reference sources for chronyd can be
|
|
RFC1305 NTP servers, human (via keyboard and \fIchronyc\fR), or the computer's
|
|
real-time clock at boot time (Linux only). chronyd can determine the rate at
|
|
which the computer gains or loses time and compensate for it while no external
|
|
reference is present. Its use of NTP servers can be switched on and off
|
|
(through \fIchronyc\fR) to support computers with dial-up/intermittent access
|
|
to the Internet, and it can also act as an RFC1305-compatible NTP server.
|
|
|
|
.SH USAGE
|
|
\fIchronyc\fR is a command-line interface program which can be used to
|
|
monitor \fIchronyd\fR's performance and to change various operating
|
|
parateters whilst it is running.
|
|
|
|
\fIchronyd\fR's main function is to obtain measurements of the true (UTC)
|
|
time from one of several sources, and correct the system clock
|
|
accordingly. It also works out the rate at which the system clock
|
|
gains or loses time and uses this information to keep it accurate
|
|
between measurements from the reference.
|
|
|
|
The reference time can be derived from either Network Time Protocol
|
|
(NTP) servers (preferred), or wristwatch-and-keyboard (via \fIchronyc\fR).
|
|
The main source of information about the Network Time Protocol is
|
|
\fIhttp://www.eecis.udel.edu/~ntp\fR.
|
|
|
|
It is designed so that it can work on computers which only have
|
|
intermittent access to reference sources, for example computers which
|
|
use a dial-up account to access the Internet. Of course, it will work
|
|
on computers with permanent connections too.
|
|
|
|
In addition, for Linux 2.0.x (for x >= 32) or 2.2 onwards, chronyd can monitor
|
|
the system's real time clock performance, so the system can maintain accurate
|
|
time even across reboots.
|
|
|
|
Typical accuracies available between 2 machines are
|
|
|
|
On an ethernet LAN : 100-200 microseconds, often much better
|
|
On a V32bis dial-up modem connection : 10's of milliseconds (from one
|
|
session to the next)
|
|
|
|
\fIchronyd\fR can also operate as an RFC1305-compatible NTP server and peer.
|
|
|
|
.SH "SEE ALSO"
|
|
.BR chronyc(1),
|
|
.BR chrony(1)
|
|
|
|
.I http://chrony.sunsite.dk/
|
|
|
|
.SH AUTHOR
|
|
Richard Curnow <rc@rc0.org.uk>
|
|
|
|
This man-page was written by Jan Schaumann <jschauma@netmeister.org> as part
|
|
of "The Missing Man Pages Project". Please see
|
|
\fIhttp://www.netmeister.org/misc/m2p2/index.html\fR for details.
|