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On Thu, 01 May 2008 16:53:18 +0000, Matt Hayes wrote:


> hwclock --systohc
>
> will sync your hardware clock to the system clock
>
my HW clock is set to UTC; if i set correctly my sys clock, will 'hwclock
--systohc' set the HW clock taking into account the delay due to timezone?
or will it just copy the sys clock to HW one?

anyway, first i need to solve to problem of DST;
my sys hasn't moved to DST whuile the HW clock is set to UTC.
> -Matt

heavytull <heavytull@hotmail.com> wrote:
>> hwclock --systohc
>>
>> will sync your hardware clock to the system clock
>>
> my HW clock is set to UTC; if i set correctly my sys clock, will 'hwclock
> --systohc' set the HW clock taking into account the delay due to timezone?

Add an extra "-u" (clock already in UTC) to the hwclock commandline
given above.

> or will it just copy the sys clock to HW one?

Without the -u it will convert UTC "system clock" to localtime and put
THAT into the hardware clock, with the -u it knows that both system
clock and hardware clock are in UTC, so no conversions needed.

See also the hwclock entries in /etc/rc.d/rc.S (for reading the hwclock
at bootup) and /etc/rc.d/rc.6 (for rewriting it from the system clock at
shutdown).
Although they nowadays use the "long form" of the option (--utc).

> anyway, first i need to solve to problem of DST;
> my sys hasn't moved to DST whuile the HW clock is set to UTC.

Neither the hardware clock nor system time SHOULD move, just your local
representation (localtime) OF it.

For instance, when I do "date" in the winter, I could get
Sun Mar 8 15:36:51 CET 2008
but today I get
Sun May 11 16:36:51 CEST 2008
(note the extra S in the timezone designation).
On the other hand "date -u" will tell me
Sun May 11 14:36:51 UTC 2008
so my "system time" is at 14:36, while my LOCAL time is 2 hours later
(CET, Central European Timezone, is 1 hour "east" of GMT, with an extra
hour because of the DST).
--
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