XP and bios

Archived from groups: microsoft.public.windowsxp.general (More info?)

<Danieltbt05@gmail.com> wrote in message
news:1122479260.734240.101140@z14g2000cwz.googlegroups.com...
> Does WinXP have a clock by itself ? If the computer battery ran weak,
> will it affect WinXP from booting up normally ? My machine battery was
> weak and the time was reset to previously. Windows can't booted into
> desktop and there is a message indicate time was incorrect. Pls advise.
> Thanks.

There are actually three clocks. The RTC is the only real clock, as it
maintains real time (RTC = Real Time Clock)even when power is off, via an
accumulator/battery. At bootup, the BIOS reads the RTC and begins counting
time independently of the RTC. Finally, Windows reads the BIOS clock and
begins counting time independently of both the RTC and BIOS. All three
clocks can go out of sync quite quickly (even the RTC is not that accurate).

When you change time in Windows (such as when synchronising to a time
server), both the BIOS and RTC clocks are updated accordingly.

But, if the accumulator/battery (usually a small NiCad rechargable battery)
fails to charge while power is on not only will the clock lose time
(ultimately resetting to the BIOS manufacture date/time), but you'll also
lose CMOS settings when power is switched off. Therefore take a note of them
before you lose them! You can normally expect to change your NiCad every 3
years or so, but many will last 5 years or more. It really depends how often
and for how long the PC is off (while power is on, it is simply recharging).

Replacing the battery should resolve your situation, but you can temporarily
work around it by changing the BIOS time before booting to Windows.

Archived from groups: microsoft.public.windowsxp.general (More info?)

Hi , so if the windows clock out of sync with bios clock with it affect
windows xp boot up process ? i mean like not responding or error.
Because when i start windows, there is a hidden error about my windows
time not correct. Windows hangs at welcome screen but i press alt+tab,
there is a hidden windows error message indicating time error. The bios
time fall back to year 2000. Exact error i didn't copy it down. After i
press enter, then it can only enter windows. Any problem like this
before ?

Regards
Daniel


Blackadder wrote:
> <Danieltbt05@gmail.com> wrote in message
> news:1122479260.734240.101140@z14g2000cwz.googlegroups.com...
> > Does WinXP have a clock by itself ? If the computer battery ran weak,
> > will it affect WinXP from booting up normally ? My machine battery was
> > weak and the time was reset to previously. Windows can't booted into
> > desktop and there is a message indicate time was incorrect. Pls advise.
> > Thanks.
>
> There are actually three clocks. The RTC is the only real clock, as it
> maintains real time (RTC = Real Time Clock)even when power is off, via an
> accumulator/battery. At bootup, the BIOS reads the RTC and begins counting
> time independently of the RTC. Finally, Windows reads the BIOS clock and
> begins counting time independently of both the RTC and BIOS. All three
> clocks can go out of sync quite quickly (even the RTC is not that accurate).
>
> When you change time in Windows (such as when synchronising to a time
> server), both the BIOS and RTC clocks are updated accordingly.
>
> But, if the accumulator/battery (usually a small NiCad rechargable battery)
> fails to charge while power is on not only will the clock lose time
> (ultimately resetting to the BIOS manufacture date/time), but you'll also
> lose CMOS settings when power is switched off. Therefore take a note of them
> before you lose them! You can normally expect to change your NiCad every 3
> years or so, but many will last 5 years or more. It really depends how often
> and for how long the PC is off (while power is on, it is simply recharging).
>
> Replacing the battery should resolve your situation, but you can temporarily
> work around it by changing the BIOS time before booting to Windows.