unruh wrote:
On 2013-07-30, David Lord <[email protected]> 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 127.127.29.1 mode 2 minpoll 4 maxpoll 4 prefer
fudge 127.127.29.1 time1 0.020
fudge 127.127.29.1 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.
Mine are backups for my gps/pps but sometimes here the internet
might not be as reliable as at your location and I've known two
or three of my backups go unreachable. My gps also has bad days
in certain weather conditions.
Could all the fudge factors go on one line?
Shouldn't be a problem.
fudge 127.127.29.1 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?
That is what is suggested in the ntp docs for the type 29
driver. The expected accuracy is given for various OS, eg
Linux 10 us.
(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.
I've now downloaded and installed ntp-4.2.7p377 and after a about 30
minutes from reboot:
remote refid st t poll reach delay offset jitter
oPPS(2) .PPSb. 0 l 64 377 0.000 -0.002 0.004
David
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