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English corrections from jdp.

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Add main purpose description (MSDOS timestamps)
This commit is contained in:
Andrey A. Chernov 1996-04-09 11:31:34 +00:00
parent 5c5a2a4672
commit f7b994d058
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=15157
1 changed files with 23 additions and 18 deletions
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41
sbin/adjkerntz/adjkerntz.8
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@ -39,15 +39,20 @@ maintains the proper relationship between the kernel clock, which
is always set to UTC, and the CMOS clock, which may be set to local
time.
.Nm Adjkerntz
also informs the kernel about machine timezone shift to
maintain proper timestamps for local time file systems like MS-DOS one.
also informs the kernel about machine timezone shifts to
maintain proper timestamps for local time file systems such as the MS-DOS
file system. The main purpose of this thing is not general fixing of
initially broken MS-DOS file timestamp idea but keeping
the same timestamps between FreeBSD MS-DOS file system
and MS-DOS operating system installed on the same
machine.
If the file
.Pa /etc/wall_cmos_clock
exists, it means that CMOS clock keep local time (MS-DOS and MS-Windows
compatible mode),
if that file does not exist it means that CMOS clock keep UTC time.
exists, it means that CMOS clock keeps local time (MS-DOS and MS-Windows
compatible mode).
If that file does not exist, it means that the CMOS clock keeps UTC time.
.Nm Adjkerntz
passes this state to
passes this state to the
.Pa machdep.wall_cmos_clock
kernel variable.
.Pp
@ -65,7 +70,7 @@ is invoked with this option from
on entry to multi-user mode, before any other daemons have been started.
.Nm Adjkerntz
puts itself into the background.
Then for wall CMOS clock
Then, for a local time CMOS clock,
.Nm adjkerntz
reads the local time from it
and sets the kernel clock to the corresponding UTC time.
@ -76,7 +81,7 @@ kernel variable, for use by subsequent invocations of
.Nm "'adjkerntz -a'"
and by local time file systems.
.Pp
For wall CMOS clock
For a local time CMOS clock
.Nm "'adjkerntz -i'"
pauses, and remains inactive as a background daemon until it
receives a SIGTERM.
@ -92,7 +97,7 @@ Then
.Nm adjkerntz
exits.
.It Cm Fl a Op Fl s
This form is used to update the wall CMOS clock and kernel
This form is used to update the local time CMOS clock and kernel
.Pa machdep.adjkerntz
variable when time zone changes occur,
e.g., when entering or leaving daylight savings time.
@ -106,24 +111,24 @@ It stores the new offset into the
kernel variable, and updates the wall CMOS clock to the new local time.
If
.Nm "'adjkerntz -a'"
was started at nonexisten time (inside timezone change), it exits
with warning diagnostic unless
was started at a nonexistent time (during a timezone change), it exits
with a warning diagnostic unless the
.Fl s
option is used, in this case
option was used, in which case
.Nm adjkerntz
sleep 30 minutes and tries again.
sleeps 30 minutes and tries again.
.Pp
This form should be invoked from root's
.Xr crontab 5
every half hour between midnight and 4am, when most modern time
zone changes occur.
Warning: don't use
Warning: don't use the
.Fl s
option in
option in a
.Xr crontab 5
command line or multiply
command line, or multiple
.Nm "'adjkerntz -a'"
copies can conflict with each other.
instances could conflict with each other.
.El
.Pp
.Nm Adjkerntz
@ -155,6 +160,7 @@ time, while its absence indicates a UTC CMOS clock.
.Xr tzset 3 ,
.Xr crontab 5 ,
.Xr rc 8 ,
.Xr mount_msdos 8 ,
.Xr sysctl 8 ,
.Xr tzsetup 8 ,
.Xr zic 8 .
@ -171,4 +177,3 @@ Andrey A. Chernov <ache@astral.msk.su>
The
.Nm adjkerntz
command appeared in FreeBSD 1.0.1.