[ntp:questions] Re: Regular 16ms jump of NTP on Windows XP SP2

Martin Burnicki martin.burnicki at meinberg.de
Thu Sep 7 13:05:54 UTC 2006


Bert Gøtterup Petersen wrote:

> Hi
> I didn't think NTP used old timers like that...
> Any idea on how to avoid this?

Do you have ntpd running with the -M option? Otherwise if another programs
ist run which modifies the Windows Multimedia Timer you will observe time
steps like this. 

Unfortunately you don't write which exact version you have installed. There
have been quite a few version each of which started with "4.2.0a at ...".
Both NTP versions which are currently available on our download page at
support the -M option and use it by default.

Another possible reason would be another program which is run once per day
and either tweaks the system time, or runs a task which lets the Windows
clock loose a timer tick (which is about 16 milliseconds).

We've had a customer where the Windows system time had lost 30 seconds (!)
every night when his database application ran some maintenance tasks.

Martin Burnicki

Meinberg Funkuhren
Bad Pyrmont

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