March 31, 2004
pcfclock
Pcfclock kernel driver
NAME
pcfdate - get the time from a radio clock and set the system time
SYNOPSIS
pcfdate [-qsuv] [device ...]
DESCRIPTION
Get and display the date and time from a pcfclock(4) device and optionally set the system time.
If no device is specified on the command line pcfdate tries to read the time from /dev/pcfclocks/[0-2] and /dev/pcfclock[0-2].
pcfdate is usually executed at boot time to set the system time.
Never run pcfdate via cron(8) to set the system time. pcfdate causes a sudden jump forwards or backwards, which can cause a variety of problems in a system. Always use the Network Time Protocol (NTP) to gradually adjust the time. A minimal /etc/ntp.conf that uses the radio clock as its reference time source typically contains the following configuration commands:
driftfile /etc/ntp.drift
server 127.127.35.0
fudge 127.127.35.0 flag2 1
server 127.127.35.0
fudge 127.127.35.0 flag2 1
OPTIONS
| -q | Do not output the time. |
| -s | Set the system time. |
| -u | Output Coordinated Universal Time instead of local time. |
| -v | Output status information. |
FILES
/dev/pcfclocks/*
/dev/pcfclock*
/dev/pcfclock*
DIAGNOSTICS
| Operation not permitted | |
| Only a privileged user may set the system time. | |
| Resource temporarily unavailable | |
| Another process is accessing the radio clock. | |
AUTHOR
Andreas Voegele
