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

Ryan Malayter malayter at gmail.com
Thu Feb 21 13:59:26 UTC 2008

On Feb 19, 10:45 am, Thierry MARTIN <thierry-mar... at ifrance.com>
> 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.

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