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Old 03-20-2008, 12:41 PM
Rex Mottram
 
Posts: n/a
Default Re: How accurate will Sun clock be over 4 hours?

Darren Dunham wrote:
> In comp.unix.solaris Dave <someplace@nowhere-nice.com> wrote:
>> I have a requirement where I need two Suns (both Netra T1s) to have
>> their clocks close to each other during an experiment that lasts 4
>> hours. During this time, neither Sun will have internet access and they
>> will not be networked to each other.
>>
>> I suspect if I sync them by NTP before the experiment starts, then they
>> will not drift by more than 500 ms over a 4 hour period. Does that seem
>> reasonable? Has anyone actually ever made medium term (few hours)
>> stability measurements of the clocks in Suns?

>
> Can you simulate the conditions beforehand (with net access)? Run NTP,
> get them all synced up. Enable logs and make sure you have driftfiles
> in place.
>
> On the client "disable ntp" in the config file so that polls are done,
> but the clock is not modified. Let it run that way in simulated
> conditions and see what your drift rate is.
>
> Temperature will likely be the biggest factor in frequency changes.
>
> If temperature is somewhat stable, 500ms should be achievable for a few
> days.


Put the indoor machine in the refrigerator.

RM
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