[ntp:questions] Re: ntp client over satellite and no CMOS battery

David J Taylor david-taylor at blueyonder.co.uk
Tue Sep 13 06:39:08 UTC 2005


Danny Mayer wrote:
> David J Taylor wrote:
>>
>> The Windows NT 4 system was restarted recently following a power
>> glitch after being up for about a year continuous, and the CMOS had
>> drifted quite a bit.  Normally, stopping NTP would update the CMOS
>> time, but if the power stops (and no UPS here) the CMOS will have
>> been running at its own rate since system startup.
>>
>
> There is code in NTP to write to the CMOS clock on Windows. See the
> following comment in ports/winnt/ntpd/nt_clockstuff.c:
>
>   /* read the current system time, and write it back to
>            force CMOS update: */
>       /************ Added back in 2003-01-26 *****************/
>
>
> Depending when your binary was built you may not have it in your
> version. Time to upgrade?

Danny,

Yes, that code was put there at my specific request.

However, it is of no use when power to the machine suddenly stops, and the 
shutdown code for NTP isn't executed.  Under those conditions, the CMOS 
can still be out by an amount depending on its free-running clock speed.

In my case, it was two or three minutes which, considering that NT4 system 
had been up for almost a year, was pretty good!

Cheers,
David 




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