[ntp:questions] Quick sync between two computers not connected to the internet

Rob nomail at example.com
Fri Mar 19 18:21:20 UTC 2010


Richard B. Gilbert <rgilbert88 at comcast.net> wrote:
> Rob wrote:
>> Richard B. Gilbert <rgilbert88 at comcast.net> wrote:
>>> The easiest thing to do if you can site an antenna where it will have an 
>>>   unobstructed view of the sky, is to purchase a "hardware reference 
>>> clock".  The cheapest goes for about $100 US.  It's called a GPS18-LVC 
>>> if memory serves me.  If my memory fails me I'm sure someone will be 
>>> delighted to point it out!  ;-)
>> 
>> A reference clock is completely unnecessary for what he wants to do,
>> let alone a view of the sky.
>> 
>> One computer can be synced to the other, and the objective has been
>> achieved.
>> 
>> I am not sure if Windows XP can act as an NTP time server without install
>> of ntpd.  It can act as a client with no problem.
>> Maybe ntpd has to be installed on one PC (with LOCAL as the reference
>> clock) and then the other can either use the w32time standard NTP service
>> or ntpd can be installed on the second PC as well.
>
> Have you ever tried synching two computers, neither of which has a 
> stable and accurate source of time?  It usually looks something like one 
> drunken driver trying to follow another!

Of course you should not configure them to follow another in both directions.
When the second computer follows the first, there is nothing instable
or wrong going on.  You can even pick the computer that has the most
stable clock before configuring them.

> PCs, in particular, tend to suffer from clock drift.  If computers did 
> have stable and accurate clocks, what would we need NTP for?

Irrelevant.  The poster said the time did not need to be accurate.
He only requires the time to be the same on both computers.  There is
nothing that a GPS receiver will add to the system to make this easier
than without it.  But of course it adds complexity and requirements.




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