[ntp:questions] Meinberg NTP monitor, silly question

unruh unruh at wormhole.physics.ubc.ca
Tue Dec 22 18:34:46 UTC 2009

On 2009-12-22, Richard B. Gilbert <rgilbert88 at comcast.net> wrote:
> David J Taylor wrote:
>> "Richard B. Gilbert" <> wrote in message 
>> news:ZJydnVuvufm1Wa3WnZ2dnUVZ_h2dnZ2d at giganews.com...
>> []
>>>> You will find that for the best performance, the NTP PC needs to be 
>>>> left running, as initial settling is not quick.
>>> "Not quick" is an extreme understatement!  It takes about 30 minutes 
>>> to get a "reasonable approximation".  It can take ten to twelve hours 
>>> to stabilize with the best possible approximation of the time.  Once 
>>> there it's good for as long as you can keep the power on and the 
>>> temperature reasonably stable.
>> Richard,
>> On one LAN-synced system it took bout 90 minutes to get to within its 
>> normal offset range, and about the same on a Windows-XP system with a 
>> GPS reference clock.  On the Windows-7 system, with a GPS ref-clock, it 
>> took about 5 hours.
>> I do wish there were some way of speeding this up - a variable loop 
>> bandwidth or something like that.
> Lots of luck.  My understanding is that it can't be done without loss of 
> accuracy and/or stability.

Nonsense. chrony does it, without loss of accuracy (chrony is about 3
times as accurate as ntp is) or stability. It will correct a few hundred
second initial error in far less time than ntp takes for a .01 sec error,
and without stepping. 

> I keep my system running 24x7 except when we have a power outrage 
> lasting longer than the run time of the UPS.
> If your power is insufficiently reliable, consider a UPS and a gasoline 
>   (or natural gas) powered generator.  If it's important enough to spend 
> money on, you can make it almost bullet proof!

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