[ntp:questions] Thunderbolt at NTP ref clock.

unruh unruh at invalid.ca
Tue Jul 30 19:35:15 UTC 2013

On 2013-07-30, David Lord <snews at lordynet.org> wrote:
> Dave Baxter wrote:
>> Hi again.
>> In reference to my other thread.
>> "THunderbolt monitor/control on Win7 ?"
>> Well, as that device seems happy in it's potential new home.
>> I've been poking about the interweb looking for info as to getting the 
>> TB used as a reference clock for NTP.
>> I found this page:-
>> http://www.eecis.udel.edu/~mills/ntp/html/drivers/driver29.html
>> That on the face of it, seems to tell me what I need.
>> So, poking arround (no changes yet) my ntp.conf file, I "think" I need 
>> this:-
>> # Trimble Thunderbolt on /dev/gps1 (first serial port)
>> server    mode 2  minpoll 4 maxpoll 4   prefer
>> fudge    time1 0.020
>> fudge    flag2 1  refid GPS
>> server 0.uk.pool.ntp.org iburst minpoll 5 maxpoll 12
>> server 1.uk.pool.ntp.org iburst minpoll 5 maxpoll 12
>> server 2.uk.pool.ntp.org iburst minpoll 5 maxpoll 12
>> Would this be suitable for general purpose local time sourcing?  With 
>> fallback to the pool if the TB burps, dies or is otherwise compromised.
> I'd add a few more public servers, I've been using five.

Why not 47?
His are backups. 3 is fine. 

>> Could all the fudge factors go on one line?
> Shouldn't be a problem.
> fudge    time1 0.020  flag2 1  refid GPS

That looks like a huge time1 fudge. Are you sure that the pool servers
do not actually give better time than does the Trimble? 

>> (Sorry to ask silly questions, but I don't know, so have to ask.)
>> If so, in what (if any) order?
>> The server currently run's FreeBSD 8.0  Uptime over 772 days now, 
>> without a hitch! Nice...   (I do plan to configure another box, running 
>> 9.x at some point to replace this one.)  
>> ntpq -crv reports (among other things)...
>> version="ntpd 4.2.4p5-a (1)"
> I'm using 4.2.6p5 but that is fairly old (Dec 2011 maybe). One
> of the 4.2.7pnnn may be a better choice although I tried both
> 4.2.4p354 and p359 on NetBSD and had problems using the stom
> driver.

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