TICKADJ(8)							    TICKADJ(8)



NAME
       tickadj - set time-related kernel variables

SYNOPSIS
       tickadj [ -Aqs ] [ -a tickadj ] [ -t tick ]

DESCRIPTION
       The  tickadj  program reads, and optionally modifies, several timekeep
       ing-related variables in older kernels that do  not  have  support  for
       precision  ttimekeeping, including HP-UX, SunOS, Ultrix, SGI and proba
       bly others. Those machines provide means to patch the kernel /dev/kmem.
       Newer  machines	with precision time support, including Solaris, Tru64,
       FreeBSD and Linux (with PPSkit patch) should NOT use the  program.  The
       particular  variables  that  can  be changed with tickadj include tick,
       which is the number of microseconds added to  the  system  time	for  a
       clock  interrupt, tickadj, which sets the slew rate and resolution used
       by the adjtime system call, and dosynctodr, which indicates to the ker
       nels  on some machines whether they should internally adjust the system
       clock to keep it in line with time-of-day clock or not.

       By default, with no arguments, tickadj reads the variables of  interest
       in  the	kernel	and  displays them. At the same time, it determines an
       "optimal" value for the value of the tickadj variable if the intent  is
       to  run the ntpd Network Time Protocol (NTP) daemon, and prints this as
       well. Since the operation of tickadj when reading the kernel mimics the
       operation of similar parts of the ntpd program fairly closely, this can
       be useful when debugging problems with ntpd.

       Note that tickadj should be run with some caution when being  used  for
       the  first  time  on  different types of machines. The operations which
       tickadj tries to perform  are  not  guaranteed  to  work  on  all  Unix
       machines and may in rare cases cause the kernel to crash.

OPTIONS
       -a tickadj
	      Set the kernel variable tickadj to the value tickadjspecified.

       -A     Set the kernel variable tickadj to an internally computed "opti
	      mal" value.

       -t tick
	      Set the kernel variable tick to the value tick specified.

       -s     Set the kernel variable dosynctodr to zero, which  disables  the
	      hardware time-of-year clock, a prerequisite for running the ntpd
	      daemon under SunOS4.

       -q     Normally, tickadj is quite verbose about what it is  doing.  The
	      -q flag tells it to shut up about everything except errors.

FILES
       /vmunix


       /unix

       /dev/kmem


BUGS
       Fiddling with kernel variables at run time as a part of ordinary opera
       tions is a hideous practice which is only  necessary  to  make  up  for
       deficiencies  in  the  implementation of adjtime in many kernels and/or
       brokenness of the system clock in some vendors kernels.	It  would  be
       much  better  if  the  kernels  were fixed and the tickadj program went
       away.



Network Time Protocol		October 7, 2006 		    TICKADJ(8)