Re: system clock...

[Simon Valiquette <v.simon@xxxxxxxx>]

Ankit Jain a écrit :
> hi
>
> i have a problem with my system clock.
>
> whenever i reboot or start my system my clock is
> incremented by around 6 hrs. after that its alright
> i.e if i correct the time it dosent mis behave but i
> dont know whats wrong in reboot or booting the sys?
>
> if somebody can help or faced this kinda situation?

  Typically, it is just a problem between the hardware clock using 
local time and the kernel using UTC (Greenwich time) or the opposite.

  You have to know that there is a hardware clock (in the BIOS) and a 
software clock.  Windows use local time for the BIOS, while Linux 
normally use UTC.  So, if you reboot in Windows, the time will be 
correct.  Since Linux think that the BIOS is in UTC, it set its software 
clock with the time it found in the BIOS, and add (or substract) hours 
depending of the user time zone.

  "date" set only the software time.  "hwclock" is the one used at boot 
time to set the software clock.

  Try this as root (or pick a look at /etc/adjtime ):

hwclock --utc
hwclock --localtime

  It shows the time of your BIOS, and one of them is probably good. 
The simpliest is to just set your software time as you did, and set the 
hardware clock the way you want (UTC or local time).

hwclock --utc       --systohc
hwclock --localtime --systohc

  If you use Windoze, takes what works from the previous commands 
(probably --localtime) otherwise it is windows that will get the time 
wrong after the next reboot.  If you use only Linux/Unix, I would prefer 
to use --UTC but both works.


  Finally, it is also possible that your timezone is not properly 
adjusted in Linux (see tzset), but most people adjust it properly during 
Linux installation.

Simon Valiquette
http://www.gulus.org

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