[time-nuts] Thunderbolt GPS TimeKeeper

Chris Albertson albertson.chris at gmail.com
Tue Jan 24 04:10:59 EST 2012


On Tue, Jan 24, 2012 at 12:23 AM, David J Taylor
<david-taylor at blueyonder.co.uk> wrote:
>> So back to time.   If the goal is keeping good time then it is best
>> not to use Microsoft Windows.  There are good technical reasons having
>> to do with the way MS Win. keeps and adjusts time.  The bottom line is
>> that you will never be able to do better then about the millisecond
>> level even with a directly attached GPS.
>
>
> I agree that Windows is not the best OS for timekeeping, but with a directly
> attached GPS/PPS device I consistently see better than the millisecond level
> with Windows.  Please see:


Ok, about half of the Windows servers have 0.5 millisecond offsets and
some have 3 millisecond offsets.   I still call that "millisecond
level".    That is very different from "microsecond level".  To me the
terms "milli level", "nano level" and so on mean "round to the nearest
three orders of magnitude."   It is a VERY course level of rounding
even more so than"rough order of magnitude" type rounding.       So I
think "micro second level" means not "within one uSec but "you are
using uSec as your units when you tell people the number"

For most casual users even 100mS is better than they need.   No one
notices if you are 100mS late for a meeting.

Chris Albertson
Redondo Beach, California




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