2
I dual boot Linux and Windows XP on my laptop. I added the following registry key in XP to support Universal Time from the BIOS:
HKLM\SYSTEM\CurrentControlSet\Control\TimeZoneInformation\RealTimeIsUniversal
The clock is set correctly when I start up XP, but if the machine wakes from sleep, the clock is off a couple hours.
Is there a way to have XP use the Universal Time setting correctly during wake up? If not, can I prevent XP from setting the clock on resume?
If the CMOS battery is dead then the clock resets itself to way back. However, this would only happen if you phyically cut power to the computer. – Joey – 2009-10-18T18:34:44.607
IMHO Windows doesn't forget the current time when asleep. The hardware clock simply doesn't advance. You're confusing sleep with reboot. – harrymc – 2009-10-18T19:06:24.000
The hardware clock advances by itself, as long as it has power. This is not something that the operating system does. Windows, however, relies on the RTC only upon startup and keeps the time itself anyway. So whenever the RTC and Windows' own timekeeping are out of sync (startup, waking from sleep/hibernation) it has to update its own clock. And that's where bugs lie; see the article I linked in my answer. – Joey – 2009-10-18T20:47:22.400