Arch Linux

Bart(t

Member

Registered: 2009-08-27

Posts: 7

From localtime to UTC on both Windows and Linux (Solved)

Hi,

It has been a while since I updated my Archlinux. I read from the news corner that it is now strongly recommended to change from localtime to UTC (http://www.archlinux.org/news/initscripts-update-1/). Since I have a dual-boot system of Archlinux and Windows 7 RC I currently use localtime for both. From what I understand is that there is now a registry fix such that Windows will also use UTC. Now my question is: is there a recommended order in updating the two operating systems? My worry is that if I update one OS to UTC then the hardware clock is probably saved as UTC at shutdown. Then starting the other OS (which still assumes localtime) might cause troubles when it reads the hardware clock which is now in UTC.

At http://social.msdn.microsoft.com/forums … e90c6e243/ they recommend the following order:
1 - Apply the registry fix in Windows
2 - Shutdown Windows and start your alternate OS
3 - Set the time right
4 - Shutdown your alternate OS and boot Windows
5 - Sleep and resume from sleep Windows

I think step 5 is necessary, because Windows messes with the clock again after a resume from suspend/hibernation.

Secondly, at https://wiki.archlinux.org/index.php/Be … #Set_clock it is stated that you should also disable Windows from syncing the time with the Internet. Does this still apply?

I can remember that Windows once corrected for daylight saving by setting the clock one hour back. Rebooting to Archlinux afterwards caused various warnings (or errors) regarding time stamps being in the future. Waiting for one hour and then boot Archlinux 'solved' the problem. Still, I would like to prevent these things when I switch to UTC.

Thoughts and recommendations are appreciated.

Last edited by Bart(t (2011-11-24 10:39:57)

artiom

Member

From: France

Registered: 2008-07-29

Posts: 111

Re: From localtime to UTC on both Windows and Linux (Solved)

I think that it is better to disable Windows from syncing the time with the Internet. It will prevent it to mess your system clock. It will be also good to disable the possibility to windows to change the clock (policy ?, stop the time service?, I am not a windows expert, just several ideas...).

Last edited by artiom (2011-11-19 11:05:38)

Bart(t

Member

Registered: 2009-08-27

Posts: 7

Re: From localtime to UTC on both Windows and Linux (Solved)

Thanks for the reply. I played on safe with this issue:
1. Stop Windows from syncing its time with the Internet.
2. Apply the registry fix in Windows
3. Reboot to Windows to be sure everything applied well
4. Assuming the time skew between localtime and UTC can't be more than 24 hours I decided to wait for roughly 24 hours to boot Archlinux (yes.. some people still have that luxury)
5. Apply UTC to Archlinux

For now, everything is running well

Last edited by Bart(t (2011-11-24 10:45:36)