[ntp:questions] no ntp synchronisation: 2s to 6s time shift !

Danny Mayer mayer at ntp.isc.org
Sat Feb 23 23:38:09 UTC 2008


Ryan Malayter wrote:
> On Feb 19, 10:45 am, Thierry MARTIN <thierry-mar... at ifrance.com>
> wrote:
>> The system I have is a (trans)portable machine. I wonder wether these
>> parameters will be ok, wherever I place it (what is the influnce of
>> temperature differences or things like that)?
>>
> 
> In my experience, laptops, especially the newer "ultra-thin" models,
> experience wide temparature swings, even when going from high CPU load
> to idle. Therefore environmental factors will likely make any "fixed"
> frequency correction you might make pretty useless.
> 
> If you need good time, you pretty much have to use the reference ntpd
> (or another full ntp daemon) on a machine that experiences high
> temperature variations.
> 
> Of course, ntpd requires an external reference. Unfortunately, most
> ntpd versions out there in the wild do not handle the changing network
> connectivity that laptops typically experience very well. They expect
> the network to be available on ntpd startup, and not change much
> thereafter. A typical suggestion to wrok around this is to setup a
> script or something to restart ntpd when your network connectivity
> changes. How this is done varies from OS to OS, and even from
> distribution to distribution on say Linux.
> 
> Improvements are being made to the most recent development versions of
> ntpd in this area (re-doing DNS lookups periodically for example). I'm
> not sure of the state of those changes, last I checked a few months
> ago they were still in the latter stages of design.

No need to look. I haven't had the bandwidth to get much done in the 
last few months. Needless to say it will be much easier to implement on 
Windows than on Unix machines as Windows uses threads so there's no 
issue with the transfer of information between processes.

Danny



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