ntp.drift - Network Time Protocol (NTP) drift file
When the NTP daemon (xntpd) is first started, it computes the error in the
intrinsic frequency of the clock on the computer it is running on. This
process usually takes about a day or two after the daemon is started to
compute a good estimate of this (and it needs a good estimate to synchron-
ize closely to its server). Once the initial value is computed, it will
change only by relatively small amounts during the course of continued
The driftfile declaration should always be included in the ntp.conf file.
This provides xntpd with complete path name to a file in which it can store
the current value of the frequency error. That way, if the daemon is
stopped and restarted, it can reinitialize itself to the previous estimate
without spending time recomputing the frequency estimate.
The ntp.drift file contains one line with the following format:
Specifies the nominal frequency offset. DO NOT modify this field.
Specifies the method used to improve system clock accuracy.
0 Specifies that xntpd runs a Phase-Locked Loop (PLL) algorithm to keep
synchronized with other hosts. This is the default.
1 Specifies the use of the PLL algorithm in the kernel. This requires
the NTP_TIME kernel option. After the option is configured in the
kernel, edit the ntp.drift file and change the flag value to 1.
See System Administration for information on the NTP_TIME kernel
Conventional name of the drift file
Commands: ntpdate(8), ntpq(8), xntpd(8), xntpdc(8)
Network Administration: Services, System Administration