[ntp:questions] Re: Mac OS X + ntpd?

Per Hedeland per at hedeland.org
Wed Feb 2 22:48:17 UTC 2005


In article <pete+usenet-EB51C5.03320101022005 at typhoon.sonic.net> Pete
Stephenson <pete+usenet at heypete.com> writes:
>
>Also, many thanks to Brad Knowles -- I'm looking into getting a Soekris 
>machine to run FreeBSD specifically for NTP. The crystal clock on the 
>Cobalt RaQ3 I presently have is wildly inaccurate -- it powered down for 
>literally 15 minutes while I did some hardware work, and when I powered 
>back on it was 12 seconds off. I'm amazed ntpd can hold it to such 
>accurate time, but it does. Amazing.

Well, that's the CMOS TOD clock, which should have little or no bearing
on ntpd's operations. Most OS'es copy its contents into the system clock
when booting, some copy the other way on (orderly) shutdown or even
occasionally when running. Chances are that your OS did neither of the
latter two, and that your TOD clock was off by 12 seconds already when
you powered down.

Rest assured that ntpd cannot usefully correct a system clock that
accumulates 12 seconds of error in 15 minutes (in case such a thing
exists, which is highly unlikely).

--Per Hedeland
per at hedeland.org



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