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clockspeed(1)		     General Commands Manual		   clockspeed(1)

NAME
     clockspeed - speed up or slow down the local clock, continuously

SYNOPSIS
     clockspeed

DESCRIPTION
     clockspeed resets the local UNIX clock every three seconds according to (1)
     an internal hardware tick counter and (2) occasional real-time measurements
     from a reliable source.

     clockspeed  reads the real-time measurements from /usr/local/clockspeed/ad-
     just.  Each real-time measurement must be	a  single  16-byte  packet,  ex-
     pressed as a TAI64NA time adjustment to the local UNIX clock.

     clockspeed  does  not  place any limits on the possible adjustments.  It is
     your responsibility to make sure that the measurements are reliable.

     After two real-time measurements, clockspeed can figure out the  number  of
     real  attoseconds	per  tick.   It  saves	this number in TAI64NA format in
     /usr/local/clockspeed/etc/atto,	    overwriting        /usr/local/clock-
     speed/etc/atto.tmp    for	  reliability.	  It   reads   /usr/local/clock-
     speed/etc/atto when it starts up again.

     clockspeed must be run by root.

SEE ALSO
     clockadd(1), clockview(1), sntpclock(1), taiclock(1), adjtime(2),	gettime-
     ofday(2)

								   clockspeed(1)

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<https://man.freebsd.org/cgi/man.cgi?query=clockspeed&sektion=1&manpath=FreeBSD+Ports+15.1.quarterly>

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