[ntp:questions] Windows time question.

Richard B. Gilbert rgilbert88 at comcast.net
Fri Apr 22 20:13:44 UTC 2011

On 4/22/2011 1:05 PM, unruh wrote:
> On 2011-04-22, Richard B. Gilbert<rgilbert88 at comcast.net>  wrote:
>> On 4/22/2011 11:22 AM, unruh wrote:
>>> On 2011-04-22, Rob<nomail at example.com>   wrote:
>>>> Hal Murray<hal-usenet at ip-64-139-1-69.sjc.megapath.net>   wrote:
>>>>>> I would have hoped that the pool folk kept their documentation up-to-date,
>>>>>> so I'll post that on their list.  You didn't mention how to control the
>>>>>> number of servers uses - is it just multiple "pool" entries?
>>>>> You only need one pool command.
>>>>>     pool<server-name>
>>>>> will use as many addresses from server-name as it needs.
>>>>> If it doesn't get enough with the first DNS lookup, it will try
>>>>> again in a minute or so, and keep trying until it gets enough.
>>>>> The default is to collect 10 servers.
>>>> If I were involved in the pool I would call that abuse!
>>>> The pool DNS lookup now returns 3 servers, used to be 5.
>>>> When everyone uses 10 servers the load on the pool as a whole is
>>>> twice what it would need to be, and 3 times what would be the minimum
>>>> reasonable value.
>>> I agree. It is absurd. It seems to indicate that the ntp folk really
>>> really do not trust the pool, and figure that if you get fewer than 10, you have a
>>> reasonable chance that a majority will deliver bad time. Ie, they appear
>>> to feel that the pool is a pretty useless souce of time.
>>>> Do the pool managers know that it works that way?
>> Anyone who doubts the accuracy, legitimacy, etc. of pool services should
>> be able to purchase a GPS timing receiver and get the time from "the
>> horse's mouth".  The investment required is about $100 US at a minimum.
>> Or, just about every country in the world has its "National Bureau of
>> Standards" equivalent and many broadcast a time signal; e.g. WWV, WWVA,
>> WWVB, WWVH, JJY, CHU(?), etc.
> I do have a GPS PPS receiver.
> But that is not the question. The question is why ntpd would demand a
> default of 10 pool servers. The only reason I could think of is that the
> developers of ntpd do not trust the pool, and feel that they need that
> many to get a reasonable expectation of accurate time from the pool.
>> If you're really paranoid, you can spend a small fortune and get an
>> "atomic clock" of your very own!  The NBS will cheerfully calibrate it
>> for you!
> GPS PPS is fine for me, thank you, but then my timekeeping wants/needs
> are not the question being addressed. What is being addressed is whether
> or not the developers of ntpd "doubts the accuracy, legitimacy, etc. of
> pool services"

Perphaps this is a recently introduced bug!  I don't recall ever hearing 
about such a thing until the last two or three days.

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