[ntp:questions] testing slew only mode (-x), not slewing correctly (linux sles10, ntpd v 4.1.1)
Richard B. Gilbert
rgilbert88 at comcast.net
Fri Oct 23 17:18:59 UTC 2009
Unruh wrote:
> E-Mail Sent to this address will be added to the BlackLists <Null at BlackList.Griffin-Technologies.invalid> writes:
>
>> Richard B. Gilbert wrote:
>>> BlackList wrote:
>>>> I guess I could see 10 minutes (or more) if the time had
>>>> never been set to anything reasonable; However 10 minutes
>>>> seems really far out for something that was previously
>>>> syncing with NTP servers (or any other source of time).
>>>>
>>> I don't see what "previously synching" has to do with anything.
>>> If previously synching means three weeks ago, it's meaningless!
>>> If it means thirty minutes ago, I would expect the clock to be
>>> within a few milliseconds of the correct time. If not I would
>>> regard the clock as broken! I'm assuming reasonably constant
>>> temperature!
>
>> If over three weeks, a cheap generic RTC gets out by 10 minutes,
>> it is broken. Thats an average of 1.6 seconds drift, in the
>> same direction, every hour?
>
> 10 min in three weeks is about 300PPM, which is not that ridiculous. You might call it
> broken but not seriously.
>
I'd call it "lunatic fringe"! Most clocks should be within 100 PPM or
less. My Sun hardware reports values in the +/~ 50 range.
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