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ntp.drift(4)							 ntp.drift(4)



NAME

  ntp.drift - Network Time Protocol (NTP) drift	file

DESCRIPTION

  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
  operation.

  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:

  freq_offset flag

  freq_offset
      Specifies	the nominal frequency offset.  DO NOT modify this field.

  flag
      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
      option.

FILES

  /etc/ntp.drift
	    Conventional name of the drift file

RELATED	INFORMATION

  Commands: ntpdate(8),	ntpq(8), xntpd(8), xntpdc(8)

  Files: ntp.conf(4)

  Network Administration: Services, System Administration