ADJTIMEX 

ñ ÂÕÄÕ ÓÞÉÔÁÔØ, ÞÔÏ ×Ù ÕÖÅ ÐÒÏÞÉÔÁÌÉ ÓÔÒÁÎÉÞËÕ man ÐÏ adjtimex :-)


÷÷åäåîéå

÷ÏÚÍÏÖÎÏ, ×Ù ÕÖÅ ÚÎÁÅÔÅ, ÞÔÏ × ×ÁÛÅÍ ËÏÍÐØÀÔÅÒÅ ÉÍÅÀÔÓÑ Ä×ÏÅ ÞÁÓÏ× -
"ÞÁÓÙ ÒÅÁÌØÎÏÇÏ ×ÒÅÍÅÎÉ" (RTC - Real Time Clock), ËÏÔÏÒÙÅ ÉÄÕÔ ×ÓÅ ×ÒÅÍÑ,
É ÓÉÓÔÅÍÎÙÅ ÞÁÓÙ, ËÏÔÏÒÙÅ ÉÄÕÔ ÔÏÌØËÏ ÐÒÉ ×ËÌÀÞÅÎÎÏÍ ËÏÍÐØÀÔÅÒÅ. ôÏÞÎÏÓÔØ
×ÙÛÅ Õ ÓÉÓÔÅÍÎÙÈ ÞÁÓÏ× (ÐÒÉÍÅÒÎÏ 1 uÓÅË), ÎÏ Õ RTC, ×ÏÚÍÏÖÎÏ, ÌÕÞÛÅ 
ÓÔÁÂÉÌØÎÏÓÔØ ÎÁ ÄÌÉÔÅÌØÎÏÍ ÐÒÏÍÅÖÕÔËÅ (long-term stability). adjtimex
ÐÒÅÄÎÁÚÎÁÞÅÎ ÄÌÑ ÐÒÉÂÌÉÚÉÔÅÌØÎÏÊ ËÏÒÒÅËÃÉÉ ÕÈÏÄÁ ÓÉÓÔÅÍÎÙÈ ÞÁÓÏ×.

RTC Ñ×ÌÑÀÔÓÑ ÕÄÏÂÎÙÍÉ ÏÐÏÒÎÙÍÉ ÞÁÓÁÍÉ


	adjtimex --compare

ÐÏËÁÚÙ×ÁÅÔ ×ÒÅÍÑ, ÒÁÚÎÉÃÕ ÍÅÖÄÕ Ä×ÕÍÑ ÞÁÓÁÍÉ, ÐÅÒ×ÏÅ ÒÁÚÌÉÞÉÅ (ËÁË ÓÉÌØÎÏ
ÓÐÅÛÁÔ ÉÌÉ ÏÔÓÔÁÀÔ ÓÉÓÔÅÍÎÙÅ ÞÁÓÙ ÐÏ ÓÒÁ×ÎÅÎÉÀ Ó ÐÏÓÌÅÄÎÅÊ Ó×ÅÒËÏÊ Ó RTC),
É Ä×Á ×ÒÅÍÅÎÎÙÈ ÐÁÒÁÍÅÔÒÁ ÑÄÒÁ: tick É ÓÄ×ÉÇ ÞÁÓÔÏÔÙ. ðÏÓÌÅ ÐÅÒ×ÙÈ Ä×ÕÈ 
ÓÒÁ×ÎÅÎÉÊ ÏÎ ÔÁËÖÅ ×Ù×ÏÄÉÔ ÒÅËÏÍÅÎÄÕÅÍÙÅ ÚÎÁÞÅÎÉÑ ÔÉËÏ× É ÓÄ×ÉÇÁ ÞÁÓÔÏÔÙ, 
ËÏÔÏÒÙÅ ÐÏÄÒÅÇÕÌÉÒÕÀÔ ÓÉÓÔÅÍÎÙÅ ÞÁÓÙ Ó ÐÒÉÂÌÉÚÉÔÅÌØÎÙÍ ÚÎÁÞÅÎÉÅÍ RTC. 
ëÏÎÅÞÎÏ, RTC ÍÏÇÕÔ ÉÍÅÀÔ ÓÏÂÓÔ×ÅÎÎÕÀ ÓÉÓÔÅÍÁÔÉÞÅÓËÕÀ ÏÛÉÂËÕ. clock(8) ÉÌÉ 
hwclock(8) ÉÓÐÏÌØÚÕÀÔ ÆÁÊÌ /etc/adjtime ÄÌÑ ÚÁÐÉÓÉ ËÏÜÆÆÉÃÉÅÎÔÁ ÕÈÏÄÁ 
(drift rate) É ×ÒÅÍÅÎÉ ÐÏÓÌÅ ÐÏÓÌÅÄÎÅÊ ÕÓÔÁÎÏ×ËÉ RTC. adjtimex ÔÁËÖÅ 
Ó×ÅÒÑÅÔÓÑ Ó ÜÔÉÍ ÆÁÊÌÏÍ É ÉÓÐÏÌØÚÕÅÔ ËÏÒÒÅËÃÉÀ ËÏ ×ÒÅÍÅÎÉ RTC.

ëÒÏÍÅ ÔÏÇÏ, adjtimex ÍÏÖÅÔ ÚÁÐÉÓÙ×ÁÔØ ×ÒÅÍÑ ÏÂÏÉÈ ÞÁÓÏ× É ÄÏÐÏÌÎÉÔÅÌØÎÏÅ
ÏÐÏÒÎÏÅ (reference) ×ÒÅÍÑ, × ÌÏÇ. úÁÔÅÍ ÜÔÏ ÓÒÁ×ÎÉ×ÁÅÔÓÑ Ó ÚÁÐÉÓÁÎÎÙÍ 
×ÒÅÍÅÎÅÍ É ÒÁÓÓÞÉÔÙ×ÁÀÔÓÑ ×ÅÌÉÞÉÎÙ ÕÈÏÄÁ (drift rates).


õóôáîï÷ëá

äÌÑ ËÏÎÆÉÇÕÒÉÒÏ×ÁÎÉÑ ÎÁÂÅÒÉÔÅ "./configure", ÄÌÑ ËÏÍÐÉÌÑÃÉÉ - "make",
ÚÁÔÅÍ "make install" ÄÌÑ ËÏÐÉÒÏ×ÁÎÉÑ ÂÉÎÁÒÎÉËÁ × /usr/local/bin, Á
ÓÔÒÁÎÉÃÙ man × /usr/local/man/man8. åÓÌÉ ×Ù ÈÏÔÉÔÅ ÕÓÔÁÎÏ×ÉÔØ ÐÒÏÇÒÁÍÍÕ
× /usr ×ÍÅÓÔÏ /usr/local, ÎÁÞÎÉÔÅ Ó "./configure --prefix=/usr".


ëòïíå ôïçï

äÌÑ ×ÙÐÏÌÎÅÎÉÑ ÂÏÌØÛÉÎÓÔ×Á ÎÉÖÅÓÌÅÄÕÀÝÉÈ ÄÅÊÓÔ×ÉÊ ×Ù ÄÏÌÖÎÙ ×ÏÊÔÉ ËÁË root.

óÔÁÎÄÁÒÔÎÏÅ ÑÄÒÏ ÎÅ ÂÕÄÅÔ ÔÒÏÇÁÔØ RTC, ÐÏËÁ ÎÅ ÂÕÄÅÔ ÕÓÔÁÎÁ×ÌÉ×ÁÔØÓÑ ÏÄÉÎ 
ÉÚ ×ÒÅÍÅÎÎÙÈ ÐÁÒÁÍÅÔÒÏ× (ÎÁÐÒÉÍÅÒ, Ó ÐÏÍÏÝØÀ adjtimex). úÁÔÅÍ, ÐÒÅÄÐÏÌÁÇÁÑ, 
ÞÔÏ ntpd ÒÅÇÕÌÉÒÕÅÔ ÓÉÓÔÅÍÎÏÅ ×ÒÅÍÑ, ÚÁÐÕÓËÁÅÔ "ËÏÒÒÅËÃÉÀ" RTC ÐÒÉÍÅÒÎÏ
ËÁÖÄÙÅ ÏÄÉÎÎÁÄÃÁÔØ ÍÉÎÕÔ. adjtimex ÐÒÅÄÏÔ×ÒÁÝÁÅÔ ÜÔÏ ÕÓÔÁÎÏ×ËÏÊ ×ÒÅÍÅÎÉ 
ÐÏÓÌÅ ÉÚÍÅÎÅÎÉÑ ÌÀÂÏÇÏ ÐÁÒÁÍÅÔÒÁ. ÷ ÄÅÊÓÔ×ÉÔÅÌØÎÏÓÔÉ ×ÒÅÍÑ ÎÅ ÉÚÍÅÎÉÔÓÑ.


éóðïìøúï÷áîéå

óÏÚÄÁÊÔÅ /etc/adjtime, ËÏÔÏÒÙÊ ÉÓÐÏÌØÚÕÅÔÓÑ clock(8) É hwclock(8) ÄÌÑ
ËÏÒÒÅËÃÉÉ ÓÉÓÔÅÍÁÔÉÞÅÓËÏÊ ÏÛÉÂËÉ × RTC. õÓÔÁÎÏ×ÉÔÅ ÅÇÏ, ËÁË ÏÐÉÓÁÎÏ ×
ÓÔÒÁÎÉÃÅ man, ÄÌÑ ËÁÖÄÏÊ ÐÒÏÇÒÁÍÍÙ. clock ×ËÌÀÞÁÅÔÓÑ (×ÍÅÓÔÅ Ó ÍÎÏÖÅÓÔ×ÏÍ
ÄÒÕÇÉÈ ÐÏÌÅÚÎÙÈ ÕÔÉÌÉÔ) × ËÏÌÌÅËÃÉÀ òÉËÁ æÜÊÔÁ (Rik Faith):
sunsite.unc.edu:pub/Linux/system/Misc/util-linux-1.10.tar.gz åÓÌÉ ×ÁÛ RTC
ÕÖÅ ÄÏÓÔÁÔÏÞÎÏ ÔÏÞÅÎ ÄÌÑ ×ÁÓ, ÐÒÏÓÔÏ ÓÏÚÄÁÊÔÅ ÆÁÊÌ /etc/adjtime, ÓÏÄÅÒÖÁÝÉÊ 
ÔÏÌØËÏ ÏÄÎÕ ÐÅÒ×ÕÀ ÓÔÒÏÞËÕ: '0.0 0 0.0'.

óÎÁÞÁÌÁ Ñ ÏÂßÑÓÎÀ ÒÕÞÎÕÀ ÐÒÏÃÅÄÕÒÕ.

óËÏÍÐÉÌÉÒÕÊÔÅ É ÚÁÐÕÓÔÉÔÅ adjtimex Ó ËÌÀÞÏÍ --compare.
ïÖÉÄÁÅÍÙÅ ÒÅÚÕÌØÔÁÔÙ ÐÒÉÍÅÒÎÏ ÔÁËÉÅ:

	# adjtimex --compare
	794625929   -0.597638 -0.597638  ...
	794625939   -0.602050 -0.004412  ...
			      ^^^^^^^^^
üÔÏ ÞÉÓÌÏ ÓÏÏÂÝÁÅÔ, ÞÔÏ ÓÉÓÔÅÍÎÙÅ ÞÁÓÙ ÏÔÓÔÁÀÔ ÂÏÌÅÅ ÞÅÍ ÎÁ 4 ÍÉÌÌÉÓÅËÕÎÄÙ
ÚÁ 10 ÓÅËÕÎÄ ÐÏ ÓÒÁ×ÎÅÎÉÀ Ó RTC, ÉÌÉ 4 ÞÁÓÔÉ ÎÁ 10000. óÌÅÄÏ×ÁÔÅÌØÎÏ,
ÍÙ Õ×ÅÌÉÞÉ×ÁÅÍ ÐÁÒÁÍÅÔÒ tick ÄÏ 10004 É ÐÏ×ÔÏÒÑÅÍ ÓÒÁ×ÎÅÎÉÅ:

	# adjtimex  --tick 10004
	# adjtimex --compare
	794626037   -0.644860 -0.644860  ...
	794626047   -0.645259 -0.000399  ...

ôÅÐÅÒØ ÓÉÓÔÅÍÎÙÅ ÞÁÓÙ ÏÔÓÔÁÀÔ ÐÒÉÍÅÒÎÏ ÎÁ 39.9 ÞÁÓÔÅÊ ÎÁ ÍÉÌÌÉÏÎ. äÌÑ 
ËÏÒÒÅËÃÉÉ ÜÔÏÇÏ ÍÙ ÍÏÖÅÍ ÉÚÍÅÎÉÔØ ÓÄ×ÉÇ ÞÁÓÔÏÔÙ (frequency offset). 
÷ÓÐÏÍÎÉÔÅ, ÞÔÏ ÓÄ×ÉÇ ÞÁÓÔÏÔÙ - ÜÔÏ × ÞÁÓÔÑÈ ÎÁ ÍÉÌÌÉÏÎ, Ó ÔÏÞËÏÊ ÄÅÌÅÎÉÑ
× ÃÅÎÔÒÅ (ÐÏ 16 ÂÉÔ Ó ËÁÖÄÏÊ ÓÔÏÒÏÎÙ). óÌÅÄÏ×ÁÔÅÌØÎÏ, ÍÙ ÕÓÔÁÎÁ×ÌÉ×ÁÅÍ 
ÓÄ×ÉÇ × 39.9*65536 = 2614886:

	# adjtimex  --frequency 2614886
	# adjtimex --compare
	794626313   -0.652147 -0.652147  ...
	794626323   -0.652247 -0.000100  ...

÷ÉÄÎÏ, ÞÔÏ ÅÓÔØ ÅÝÅ ÒÁÚÎÉÃÁ ÏËÏÌÏ 10 ppm, ÐÏÜÔÏÍÕ ÍÙ Õ×ÅÌÉÞÉÍ ÓÄ×ÉÇ ÎÁ
10*65536, ÄÏ 3270246:

	# adjtimex  --frequency 3270246
	# adjtimex --compare
	794627233   -0.795221 -0.795221  ...
	794627243   -0.795231 -0.000009  ...

ôÁËÉÍ ÖÅ ÏÂÒÁÚÏÍ ×ÙÓÞÉÔÙ×ÁÀÔÓÑ ÚÎÁÞÅÎÉÑ × ËÏÌÏÎËÅ "suggested" ("òÅËÏÍÅÄÎÏ×ÁÎÏ").
ðÒÉÍÅÎÅÎÉÅ ËÌÀÞÁ --adjust Á×ÔÏÍÁÔÉÚÉÒÕÅÔ ÐÒÏÃÅÓÓ - ÐÅÒÉÏÄÉÞÅÓËÉ ÕÓÔÁÎÁ×ÌÉ×ÁÑ
"ÒÅËÏÍÅÎÄÕÅÍÙÅ" ÚÎÁÞÅÎÉÑ.

ëÓÔÁÔÉ, ÉÓÐÏÌØÚÏ×ÁÎÉÅ ÏÐÃÉÊ --offset ÉÌÉ --singleshot ËÁÖÅÔÓÑ ÉÍÅÀÔ
ÄÌÉÔÅÌØÎÏÅ ÄÅÊÓÔ×ÉÅ ÎÁ ÞÁÓÙ. ñ ÒÅËÏÍÅÎÄÕÀ ×ÁÍ ÏÐÒÅÄÅÌÉÔØ ÚÎÁÞÅÎÉÑ tick É 
ÞÁÓÔÏÔÙ ÄÏ ÐÒÉÍÅÎÅÎÉÑ ÄÒÕÇÉÈ ÏÐÃÉÊ.

õ ×ÁÓ ÕÖÅ ÍÏÖÅÔ ÂÙÔØ ÚÁÐÉÓØ, ÐÏÄÏÂÎÁÑ ÜÔÏÊ, × /etc/rc.d/rc.S, /etc/init.d/boot 
ÉÌÉ ÏÄÎÏÍ ÉÚ ÄÒÕÇÉÈ ÓÔÁÒÔÏ×ÙÈ ÆÁÊÌÏ×:

	# Adjust CMOS clock based on /etc/adjtime, then set system clock.
	# Add -u switch if your system keeps GMT.
	if [ -x /sbin/clock ]; then
	  /sbin/clock -a
	fi

ðÒÏÓÔÏ ÄÏÂÁ×ØÔÅ ÚÁÐÉÓØ ÔÉÐÁ ÜÔÏÊ:

	# Regulate the sytem clock
	if [ -x /sbin/adjtimex ]; then
	  /sbin/adjtimex  --tick 10004  --frequency 3270246 
	fi


ðòïäïìöéôåìøîùå óòá÷îåîéñ

adjtimex ÍÏÖÎÏ ÉÓÐÏÌØÚÏ×ÁÔØ ÄÌÑ ÚÁÐÉÓÉ ÚÎÁÞÅÎÉÊ ×ÒÅÍÅÎÉ CMOS É ÓÉÓÔÅÍÙ,
É ÄÏÐÏÌÎÉÔÅÌØÎÏÇÏ ÏÐÏÒÎÏÇÏ (reference) ×ÒÅÍÅÎÉ, ÞÔÏÂÙ ÍÏÖÎÏ ÂÙÌÏ ÏÐÒÅÄÅÌÉÔØ
ËÏÜÆÆÉÃÉÅÎÔ ÕÈÏÄÁ ÚÁ ÄÌÉÔÅÌØÎÙÅ ÐÅÒÉÏÄÙ. äÌÑ ÒÕÞÎÏÇÏ ××ÏÄÁ ÏÐÏÒÎÏÇÏ 
×ÒÅÍÅÎÉ ÉÓÐÏÌØÚÕÊÔÅ

	# adjtimex  --log --watch

adjtimex ÐÏÐÒÏÓÉÔ ×ÁÓ ÎÁÖÁÔØ ËÌÁ×ÉÛÕ, ËÏÇÄÁ ×Ù ÚÎÁÅÔÅ ×ÒÅÍÑ, ÚÁÔÅÍ
ÓÐÒÏÓÉÔ ×ÒÅÍÑ É ÐÒÉÂÌÉÚÉÔÅÌØÎÕÀ ÔÏÞÎÏÓÔØ. úÁÔÅÍ ÓÐÒÏÓÉÔ ÂÙÌ ÌÉ ÓÂÏÊ ËÁËÉÈ
ÌÉÂÏ ÞÁÓÏ× Ó ÍÏÍÅÎÔÁ ÐÏÓÌÅÄÎÅÊ ÚÁÐÉÓÉ × ÌÏÇÅ. ÷ÒÅÍÑ ×Ù ÍÏÖÅÔÅ ×ÚÑÔØ Ó 
ÔÏÞÎÙÈ ÞÁÓÏ×, ÒÁÄÉÏÍÁÑËÁ ×ÒÅÍÅÎÉ ÔÉÐÁ WWV ÉÌÉ CHU É Ô.Ä.

åÓÌÉ Õ ×ÁÓ ÕÓÔÁÎÏ×ÌÅÎ ntpdate (ÞÁÓÔØ ÐÁËÅÔÁ xntp) É ËÏÍÐØÀÔÅÒ ÐÏÄËÌÀÞÅÎ
Ë ÓÅÔÉ, ÉÓÐÏÌØÚÕÊÔÅ

	# adjtimex  --log  --host www.xxx.yyy.zzz

É adjtimex ÂÕÄÅÔ ÉÓÐÏÌØÚÏ×ÁÔØ ntpdate ÄÌÑ ÚÁÐÒÏÓÁ ×ÒÅÍÅÎÉ Ó ÕËÁÚÁÎÎÏÇÏ
ÈÏÓÔÁ. (õÔÏÞÎÉÔÅ Õ Ó×ÏÅÇÏ ÐÒÏ×ÁÊÄÅÒÁ, ÉÍÅÅÔ ÌÉ ÏÎ ÓÅÒ×ÅÒ ×ÒÅÍÅÎÉ NTP, 
ÉÌÉ ËÁËÏÊ ÏÎ ÍÏÖÅÔ ÐÒÅÄÌÏÖÉÔØ.)

ðÏÓÌÅ ÔÏÇÏ, ËÁË ×Ù ÓÄÅÌÁÅÔÅ ÎÅÓËÏÌØËÏ ÚÁÐÉÓÅÊ × log, ×Ù ÍÏÖÅÔÅ ÚÁÓÔÁ×ÉÔØ
adjtimex ÐÒÏÓÍÏÔÒÅÔØ ÌÏÇ Ó ÐÏÍÏÝØÀ

	# adjtimex  --review

ïÎ ×ÏÚØÍÅÔ ËÁÖÄÕÀ ÐÁÒÕ ÚÁÐÉÓÅÊ ÌÏÇÁ × ÃÉËÌÅ É ×ÙÞÉÓÌÉÔ ÄÌÑ ÎÉÈ ËÏÜÆÆÉÃÉÅÎÔ
ÏÛÉÂËÉ × ÞÁÓÔÑÈ ÎÁ ÍÉÌÌÉÏÎ (ppm) Ó ÚÁÄÁÎÎÏÊ ÔÏÞÎÏÓÔØÀ. ôÁËÖÅ ÂÕÄÕÔ ÎÁÊÄÅÎÙ
ÕÓÒÅÄÎÅÎÎÙÅ ÏÛÉÂËÉ É ÐÒÅÄÌÏÖÅÎÙ ÚÎÁÞÅÎÉÑ ÐÁÒÁÍÅÔÒÏ× ÄÌÑ ËÏÒÒÅËÔÉÒÏ×ËÉ ÕÈÏÄÁ. 
ðÒÏ×ÅÒØÔÅ ÓÏÇÌÁÓÏ×ÁÎÎÏÓÔØ ÒÅÚÕÌØÔÁÔÁ. ïÄÎÁ ÎÅÐÒÁ×ÉÌØÎÁÑ ÚÁÐÉÓØ ÏÐÏÒÎÏÇÏ 
×ÒÅÍÅÎÉ ÍÏÖÅÔ ÐÏÇÕÂÉÔØ ×ÓÅ ×ÙÞÉÓÌÅÎÉÑ.


äáìøîåêûáñ éîæïòíáãéñ

á×ÔÏÒÉÔÅÔÎÕÀ ÄÏËÕÍÅÎÔÁÃÉÀ ÐÏ ÐÒÏÇÒÁÍÍÅ ×ÒÅÍÅÎÉ ÑÄÒÁ ÓÍÏÔÒÉÔÅ ÓÄÅÓØ,
×ÓÅ ÎÁÐÉÓÁÎÏ David L. Mills <mills@udel.edu>:

[MIL92a] Mills, D.L. Network Time Protocol (Version 3) specification,
implementation and analysis, RFC 1305, University of Delaware, March
1992, 113 pp.

[MIL92c] Mills, D.L. Simple Network Time Protocol (SNTP), RFC 1361,
University of Delaware, August 1992, 10 pp.

[MIL94a] Mills, D.L. A kernel model for precision timekeeping. ARPA
Network Working Group Report RFC-1589, University of Delaware, March
1994. 31 pp.

README.kern, ËÏÔÏÒÙÊ ÍÏÖÎÏ ÎÁÊÔÉ ÎÁ louie.udel.edu:/pub/ntp/kernel.tar.Z.


âìáçïäáòîïóôé

äÜ×ÉÄÕ íÉÌÌÓÕ (David Mills) ÚÁ ËÏÄ ÓÏÈÒÁÎÅÎÉÑ ×ÒÅÍÅÎÉ ÑÄÒÁ, É óÔÉ×ÅÎÕ
äÉËÕ (Steven Dick) <ssd@nevets.oau.org> ÚÁ ÐÅÒ×ÏÎÁÞÁÌØÎÏÅ ÎÁÐÉÓÁÎÉÅ 
adjtimex. (ñ ÓÉÌØÎÏ ÉÚÍÅÎÉÌ ËÏÄ. ìÀÂÙÅ ÐÒÏÂÌÅÍÙ - ÍÏÑ ÏÔ×ÅÔÓÔ×ÅÎÎÏÓÔØ.)
âÌÁÇÏÄÁÒÎÏÓÔØ ÔÁËÖÅ íÉËÁÜÌÀ íÅÓËÅÓÕ (Michael Meskes) <meskes@debian.org>, 
ÞÅÊ ÉÎÓÔÁÌÌÑÃÉÏÎÎÙÊ ÓËÒÉÐÔ × Debian ×ÄÏÈÎÏ×ÉÌ ÎÁ ÏÐÃÉÉ "--compare" É
"--adjust".


îÁÓÌÁÖÄÁÊÔÅÓØ!
                - Jim Van Zandt <jrv at comcast.net>