Dave Hart wrote:
[]
Tiny Ben is a simple program. [1] NTPmonitor is a bit less simple.
Tiny Ben meets superscientist who's into shaving seconds and
cloning :)
[]
[1] http://www.satsignal.eu/software/disk.html#TinyBen
[]
Cheers,
Dave Hart
Tiny Ben is a simple analog clock program. It
Rob wrote:
[]
What I want to state is: somebody has a Windows domain and is asking
how
he can check if its time is similar to some external ntp server.
Windows provides the w32tm command with the /monitor flag that
accomplishes exactly that. The user did not ask how he could get
better
Rob wrote:
[]
I wanted to describe the general situation seen on this group, not
really the particular responses that you gave. There were several
replies that suggested to first install different software.
Probably best to start a new topic, then.
Cheers,
David
Unruh wrote:
David J Taylor
[]
Another PC in the same room running a FreeBSD system has about half
the jitter, but far less offset - PC Pixie at the top:
http://www.satsignal.eu/mrtg/performance_ntp.php
That looks much more like the kind of timing I get on my Linux system.
driven by a PPS
Dave Hart wrote:
[]
The 150us offsets are while slewing to try to catch up with the 3ppm
frequency shift as the heat comes on. I have to imagine a Windows PC
with a more stable oscillator (lower temperature coefficient to
frequency) would do better, though I'm not deluding myself that it
Dave Hart wrote:
Unusually for me, the configuration and code on my reference clock
test machine has been static for the last two days UTC. I've posted
loopstats and graphs for that period on http;//davehart.net/ntp/
refclock/
[]
Cheers,
Dave Hart
The program which Dave used to produce his
Unruh wrote:
[]
Gads, those offsets are huge. And 3PPM variation is also pretty big.
Dell 4400 hardware sitting in a non-temperature controlled environment -
warm in the day, cold at night. I would happily accept five times the
jitter for a fifth of the offset!
Cheers,
David
Unruh wrote:
[]
Maybe when someone finally put refclock support into chrony you will
have
your wish.
Not until it runs under Windows.
It sounds like your temp changes causing rate changes on a
scale
that ntp cannot properly cope with. (ntp is terrible at coping with
changes-- a purposeful
paul.cro...@softwareag.com wrote:
Joseph,
If you're not willing to get the source code for NTP and compile it,
you can download a binary from http://www.sunfreeware.com/.
It's probably configured with a 'standard' set of
refclock drivers and, as a consequence, may be larger
than a
David Woolley wrote:
David J Taylor wrote:
i.e. server B and C have a space rather than any other character. Those
servers are fine, but they are both actually syncing from
server A. Space appears to be defined as:
The peer is discarded as unreachable, synchronized to this server
(synch
Steve Kostecke wrote:
On 2009-03-13, David J Taylor david-tay...@blueyonder.co.uk wrote:
[]
it would be helpful if the most recent version were the first hit
returned.
I have no idea if that's possible with ht://dig.
The best I can do right now is to make the home page search default
Steve Kostecke wrote:
On 2009-03-13, Steve Kostecke koste...@ntp.org wrote:
On 2009-03-13, David J Taylor david-tay...@blueyonder.co.uk wrote:
it would be helpful if the most recent version were the first hit
returned.
The best I can do right now is to make the home page search default
Steve Kostecke wrote:
On 2009-03-12, David J Taylor david-tay...@blueyonder.co.uk wrote:
I tend to use Google, which for ntpq brings up:
http://www.cis.udel.edu/~mills/ntp/html/ntpq.html
The documentation at that URL tracks the development version of NTP
and may not be correct for stable
Steve Kostecke wrote:
On 2009-03-13, David J Taylor david-tay...@blueyonder.co.uk wrote:
Steve Kostecke wrote:
On 2009-03-13, David J Taylor david-tay...@blueyonder.co.uk wrote:
Can that documentation be updated?
doc.ntp.org is an archive of the documentation released with
specific
Martin Burnicki wrote:
David J Taylor wrote:
David J Taylor wrote:
[]
On the Intel 6600 dual-core, 2.4GHz processor here, under XP, a
RDTSC takes about 4.2ns, and a OS call to timeGetTime takes about
11.8ns. At least, they do if my measurement program is working
correctly
Haven't
Dave Hart wrote:
On Mar 11, 6:28 pm, David J Taylor david-tay...@blueyonder.neither-
this-bit.nor-this.co.uk wrote:
Folks,
I'm seeing an ntpq -p display like:
* server-A 377
server-B 377
server-C 377
i.e. server B and C have a space rather than any other character.
Those servers
Dave Hart wrote:
[]
The only table I can find on the official site is:
http://www.cis.udel.edu/~mills/ntp/html/decode.html
where the description is: discarded as not valid (TEST10-TEST13)
Does it also have a more detailed description of TEST12?
Yes: peer synchronization loop
[]
I
David Woolley wrote:
David J Taylor wrote:
David Woolley wrote:
[]
David, do you have a reference for your risks lost ticks statement
as applied to Windows?
Windows has been mentioned on this newsgroup as losing ticks on many
occasions. The fastest multi-media timers correspond
Martin Burnicki wrote:
[]
The problem can be avoided if I force the system to use the PM timer
for QPC, using the /usepmtimer flag in the Windows boot.ini as
suggested in http://support.microsoft.com/kb/833721/en-us
[]
On the following page there is an overview which timer is used by
which
Terje Mathisen terje.mathisen at tmsw.no wrote:
Martin Burnicki wrote:
Here, 2 consequent QPC calls retrun a difference of ...
350..400 ns using TSCs on an Intel 3 GHz CPU
That's horrible!
Since the RDTSC takes less than 10 ns on that cpu, the remaining
340-390 ns is lost in the OS library
David J Taylor wrote:
[]
On the Intel 6600 dual-core, 2.4GHz processor here, under XP, a RDTSC
takes about 4.2ns, and a OS call to timeGetTime takes about 11.8ns.
At least, they do if my measurement program is working correctly
Haven't checked QPC.
Cheers,
David
Richard B. Gilbert wrote:
David J Taylor wrote:
David Woolley wrote:
[]
You won't get millisecond accuracy on Windows. Although the
software clock can be disciplined to better than a millisecond,
applications can only read to one tick, which is 10ms by default
and 1ms with the fastest
Danny Mayer wrote:
David J Taylor wrote:
David Woolley wrote:
Danny Mayer wrote:
Increased polling frequency increases jitter.
I think jitter was being used loosely here, not with the specific
sense of high frequency variations.
Yes, my original question referred to looking at a graph
regan_russ...@hotmail.com wrote:
[]
My code (and project) works, I learnt a lot (a real lot believe me)
and I have to start on clean up, an installer and documentation, maybe
tomorrow.
[]
Regan
Regan,
You might want to look at InnoSetup, in case you don't already know it.
Cheers,
David
Danny Mayer wrote:
[]
Why would the account even be in the adminstrators group? It shouldn't
even be in the users group since that also has too many privileges.
It could be there because you have put it there during testing a new
version, to allow change of priority. It's a lot quicker to do
Danny Mayer wrote:
Dave Hart wrote:
[]
He didn't even mention Windows, why would you expect him to be using
Windows utilities? As far as I can tell you have made no patches
available against 4.2.4p6 and they don't belong there anyway. They
should be in the ntp-dev branch.
Danny
I, for
Martin Burnicki wrote:
David,
David J Taylor wrote:
Richard B. Gilbert wrote:
[]
I've been using Comcast for five or six years now without a problem!
YMMV.
There have been a few problems with my ISP, hence I moved to a 3rd
party.
We did't ever have any problems using the DNS servers
Martin Burnicki wrote:
David J Taylor wrote:
Martin Burnicki wrote:
However, if several local subnets needed to resolve microsoft.com
then each one would have to ask the root servers the first time.
Wouldn't you have one or two central DNS servers for both subnets?
Sorry, I've been
Maarten Wiltink wrote:
David J Taylor
david-tay...@blueyonder.neither-this-bit.nor-this.co.uk wrote in
message news:jzqtl.5203$lc7.2...@text.news.virginmedia.com...
Martin Burnicki wrote:
[...]
We did't ever have any problems using the DNS servers of our ISPs.
At the time, mine was using
jack wrote:
Hi everyone,
First of all, I thank you for all your response.
I understand the best solution would be using an IRIG board and that's
what we had been using. We are now trying to make our product more
compact by using a small single board PC with no RS 232 or PCI slot
(no slot
Unruh wrote:
[]
The newer x version appears to be a lot more sensitive, at the
expense of somewhat higher current consumption. You can tell the
LVC version what sentences to send. Better check the technical spec
to see what the USB one can be told to do:
Richard B. Gilbert wrote:
[]
Where, other than your ISP, would you go for DNS? If you are a home
user what choices do you have? If you are responsible for a
multi-user site it may make sense to operate your own DNS? I'm
working from a two-user site and using my ISP's DNS. I'm paying
Richard B. Gilbert wrote:
[]
I've been using Comcast for five or six years now without a problem!
YMMV.
There have been a few problems with my ISP, hence I moved to a 3rd party.
I could set up my own DNS server but what would be the point? A hosts
file provides the addresses of the nodes
jack wrote:
Hi all,
I am trying to sync my Windows box to an external GPS source. I
currently have BU353, whose output is not very periodic. I read up on
ntpd implementation that uses PPS signal but I don't even have an RS
232 port on my computer.
My questions:
1) what's the best GPS
Unruh wrote:
[]
How do you get the signal in now? Do you have a parallel port?
USB is terrible. But then Windows is terrible as well, so the two
probably are about equivalent. If you can use the PPS you can get a
few microseconds accuracy on a Linux/BSD ssytem. I think on Windows
you are
Dave Hart wrote:
On Mar 2, 1:46 pm, David J Taylor david-tay...@blueyonder.neither-
this-bit.nor-this.co.uk wrote:
Folks,
Dave Hart asked that I post this information:
Very briefly, I happen to have a 100Hz system, and have been playing
with the improved version of ntpd.exe on a Windows
Harlan Stenn wrote:
[]
Appreciated, and again, I was speaking to an audience that included,
but was not limited to, you.
Thanks, Harlan.
I welcome the efforts to put NTP on a sounder financial footing. The best
I can do with the companies I work for is to make them aware of NTP, which
I do.
Richard B. Gilbert wrote:
[]
I ran into this when a Norton Anti-Virus site would not let me renew
my license. Short of sending them snail-mail there was NO way to let
them know their site was badly broken!
I installed a competing product (freeware) and have not had any
problems with it or
http://www.ntp.org/ = a blank page in both Firefox and Internet Explorer
Is this correct?
Thanks,
David
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questions mailing list
questions@lists.ntp.org
https://lists.ntp.org/mailman/listinfo/questions
Terje Mathisen terje.mathisen at tmsw.no wrote:
David J Taylor wrote:
http://www.ntp.org/ = a blank page in both Firefox and Internet
Explorer Is this correct?
No, it works here, now (20 minutes after your post).
Terje
Thanks, Terje. Still blank here. I'm using OpenDNS servers.
Sorry
Rob wrote:
David J Taylor
david-tay...@blueyonder.neither-this-bit.nor-this.co.uk wrote:
Terje Mathisen terje.mathisen at tmsw.no wrote:
David J Taylor wrote:
http://www.ntp.org/ = a blank page in both Firefox and Internet
Explorer Is this correct?
No, it works here, now (20 minutes
Steve Kostecke wrote:
On 2009-03-03, David J Taylor david-tay...@blueyonder.co.uk wrote:
Guess I will wait for OpenDNS to become updated...
http://www.opendns.com/support/article/197 lists the OpenDNS
nameserver addresses.
$ host www.ntp.org 208.67.220.220
www.ntp.org
Steve Kostecke wrote:
On 2009-03-03, David J Taylor david-tay...@blueyonder.co.uk wrote:
[]
I did not complain, I asked whether what I was seeing was correct,
and some others confirmed this.
Quibling over which word I used misses the point.
To me there is a distinct difference between
Steve Kostecke wrote:
[]
The canonnical address for contacting the individuals responsible for
the operation of any web-site is webmas...@thedomain. One does not
need to see a web-page to learn this.
Steve, I'm delighted to hear that ntp.org still conform to this
convention, but very many Web
I know it's probably one of those how long is a piece of string
questions but
Does anyone know an approximate relationship between polling interval and
peak-to-peak jitter for a non-ref-clock system? I.e would the jitter
offset) go up linearly with polling interval, or as the square, or
David Woolley wrote:
David J Taylor wrote:
Does anyone know an approximate relationship between polling interval
and peak-to-peak jitter for a non-ref-clock system? I.e would the
jitter offset) go up linearly with polling interval, or as the
square, or what?
Do you mean true jitter (RMS
David Woolley wrote:
David J Taylor wrote:
Neither, directly. I mean the peak-to-peak variation in the reported
offset, as measured by eye on a graph like the Daily graph here:
For a Millsian network, the peak to peak value would be unbounded, so
one needs to consider RMS, or assume a non
Unruh wrote:
[]
YOu have a couple of answers, both of which are probably wrong and are
asking which it is. As stated your premise is bad. It depends is the
best
answer you are going to get. It depends on the source of the jitter.
Measurement noise? clock drift noise? assymetric network
Unruh wrote:
[]
Mill's assumptions about the behaviour of clocks is almost certainly
wrong.
Not least because computer clocks are in a highly variable thermal
environment. This means that the drift rate varies with time of day
and day
of week and is NOT 1/f or any other time invariant
Harlan Stenn wrote:
In article f26ql.803$lc7...@text.news.virginmedia.com, David J
Taylor david-tay...@blueyonder.neither-this-bit.nor-this.co.uk
writes:
David Thanks for that, Dave. It's a pity that a change available in
2003 David hadn't made it into my 2005 download!
This is why I
Dave Hart wrote:
On Feb 27, 5:38 pm, Dave Hart daveh...@gmail.com wrote:
When Dr. Mills first announced the change allowing the other peers'
intervals to go up with a refclock configuration, I believe he
observed a benefit from the mixed poll intervals, but he was thinking
at least two levels
Dave Hart wrote:
On Feb 26, 11:27 pm, David J Taylor
david-tay...@blueyonder.neither- this-bit.nor-this.co.uk wrote:
Well, by observation, /all/ the servers are polled at 64s intervals,
and not just the lan-gps-pps server.
Since your clients are naturally preferring the stratum 1 on the same
Dave Hart wrote:
[]
Thats doesn't seem to happen with my FreeBSD system, if I am
understanding you correctly. Admittedly I have ntpd 4.2.0-a, but all
servers have a 64s polls even though there is no minpoll or maxpoll
specified.
I'm not sure how long ago the change happened, but it appears
Folks,
It's been suggested that if I have a mixture of a known-good (i.e.
GPS/PPS-based) LAN server, and some Internet-based backup servers, I could
use an ntp configuration file with different maxpolls, with the idea that
syncing more often to a good source will produce even lower offsets.
Unruh wrote:
David J Taylor
server lan-gps-pps prefer iburst maxpoll 6
server 0.uk.pool.ntp.org iburst
server 1.uk.pool.ntp.org iburst
server 2.uk.pool.ntp.org iburst
If I do this, is the maxpoll for the Internet servers also clamped
at 6, or will it gradually up to 1024s (10
Danny Mayer wrote:
[]
If that is the case you are probably better off using the reference
implementation of ntp which disciplines your clock on an ongoing basis
by adjusting the frequency of the clock and not just sets the time. I
can't tell for sure but I believe that Tardis just sets the
Unruh wrote:
[]
On Linux these days, even a drift file that is 10 sec old is useless,
since the system clock drift rate changes by up to 50PPM over a
reboot.
So use a more appropriate OS.
David
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questions mailing list
questions@lists.ntp.org
David Woolley wrote:
David J Taylor wrote:
Would it be any better for the routine to lie, and just give to the
nearest MHz, rounded down?
That would result in an excessive error for those not using time
synchronisation software,
I might say /tough/!
and would produce extreme instability
Hal Murray wrote:
Linux seme to be having a real real problem with its time
calibration routines. It's drift rate jumps on reboot by up to
50PPM from one reboot to the next.
Really? I don't recall ever seeing that.
I thought it was well known. It's been discussed here several/many
times.
Unruh wrote:
[]
Yes, but that same manual says that the voltage for the 18PC version
is 8-30V. It says nothing about the internal voltage being the 4.5 to
5.5 V.
And the 18PC and the 18LVC are different units with different inputs
and
outputs.
The PC is also the one with serial port output
vinodkumar.pa...@wipro.com wrote:
Hello All : I am not sure whether this question is already raised and
answered, I checked the mailing list but could not track
any related questions, my question is whether SNTP client can
inter-operate with a NTP version 3 server.
Thanks for your help
Unruh wrote:
David J Taylor
[]
I would be surprised if the internal electronics differed
significantly between the PC and the LVC.
I would not be surprized either way. The units differ. One puts out
PPS, th
e other does not. The USB puts out USB
signal trains. The LVC and PC put out NMEA
Unruh wrote:
[]
OK, interesting if true. YOu are saying that if you cut the lighter
adapter
off, you should supply 4.5-5.5V But the unit claims to be serial port
device which has a nominal 12V output. I would expect that the power
supply would then
be at least that.
Why not check the
Dave Hart wrote:
On Jan 12, 6:52 pm, ma...@ntp.isc.org (Danny Mayer) wrote:
We won't be supporting IPv6 on Windows
2000, it's just too difficult to deal with from a support point of
view.
OK, Windows 2000 is too difficult to deal with from a support point of
view. Why on earth have we been
Heiko Gerstung wrote:
Hi there!
[]
Sorry for the fuzz and trouble, I hope we catched this early enough.
Any questions? Please contact us at ntp-supp...@meinberg.de ...
Best Regards,
Heiko
Heiko,
Thanks for the update. I now have the running on all my Windows PCs
(Windows 2000
Danny Mayer wrote:
David J Taylor wrote:
Heiko,
[]
One question is whether, on Vista, the installer should provide the
option of opening port 123/udp to the outside world so that systems
can be monitored or managed? It would be nice to have it in the
installer, with the default off
Martin Burnicki wrote:
[]
Here are a few thoughts:
[]
5.) Finally, in order to be able to distribute a single binary which
can be run on Windows with or without support for IPv6 the program
fully needs to check at runtime whether IPv6 support is available, or
not. I.e. it first has to try to
Diego Ramos wrote:
My Boss is going to buy the 3 Garmin models, so we can run tests and
define which one is the best solution for the company.
I told him I'll try to make the boards. :-)
Diego,
This is my simple system - if it helps:
http://www.satsignal.eu/ntp/FreeBSD-GPS-PPS.htm
I made
Chris wrote:
[]
Out of curiosity, how much time was spent porting ntpd to compile in
win32? Since it appears the project is closed source, I'm interested
in porting it myself.
Chris,
I'm sure you can download all the sources, including the Windows port.
Why do you say it's closed source? I
Folkert van Heusden wrote:
[]
Does a valid NTP source need to set the reftime to something valid?
Does the ntp spec say so?
I can't tell you that, Folkert, but, in your particular environment, would
/you/ trust a NTP source which was last synched 3 days ago?
David
Brian Utterback wrote:
David J Taylor wrote:
If Solaris or HP-UX is still supplying NTP 3, I would be rather
worried.
Be worried then. The latest bundled version of NTP on Solaris is xntpd
3-5.93e.
Not too worried though. I hope to have V4 available in OpenSolaris
soon.
Brian Utterback
Danny Mayer wrote:
David J Taylor wrote:
Unruh wrote:
[]
Of course if the unix system time were TAI then the leapsecond issue
would not arise as far as the kernel were concerned. It would be
cleaner to have the kernel on TAI and the translation to user space
time via zoneinfo using
j...@specsol.spam.sux.com wrote:
[]
Solaris 10 Update 6 IS the latest release of Solaris and the provided
NTP is nowhere near the latest downloadable version of NTP.
I would have to check, but I am pretty sure the same is true for
HP-UX.
Not everyone runs Linux nor do they usually choose a
Unruh wrote:
[]
Of course if the unix system time were TAI then the leapsecond issue
would not arise as far as the kernel were concerned. It would be
cleaner to have the kernel on TAI and the translation to user space
time via zoneinfo using a leapseconds file.
I don't like that idea,
j...@specsol.spam.sux.com wrote:
[]
What planet do you people live on?
I have one client that will not even allow Windows critical security
updates to be installed until a extensive formal test is done to
prove the updates won't effect operations.
This is hardly a unique operation.
Well, I
Folkert van Heusden wrote:
I don't recall ever seeing a report of NTP causing problems with
normal operations.
Sorry for being anal on this but:
Well almost: certain versions of the linux kernel under certain
specific conditions would panic when ntp introduces a leap second.
j...@specsol.spam.sux.com wrote:
[]
The point is LOTS of places have extensive procedures in place that
must be followed before any software on production systems can be
changed, including applying vendor supplied and recommended patches.
While I have free reign to do anything I want with my
j...@specsol.spam.sux.com wrote:
[]
You do understand there are lots of environments where it takes an
act of God to be allowed to replace vendor utilities with self
compiled versions, don't you?
Not a problem with Windows, fortunately. G
David
Laws, Peter C. wrote:
I enjoyed my extra second, how about you?
I was amused that WWV announced that it was *going to* happen in the
4th minute ... after the insertion. :-)
Well, thankfully it was a complete non-event here:
http://www.satsignal.eu/ntp/ntp-events.htm#2008-12-31
My thanks
Unruh wrote:
[]
OK, the leap second passed. My one ntp machine handled it fine.
Same here - a non-event so my thanks to all those who designed and coded
correctly.
Here is the output from my GPS 18LVC.
[]
That's most interesting, Bill. I've added it to my Web page:
George R. Kasica wrote:
[]
What sort of weather info do you process? Here is map and forecast
generation and storage, serving out over web, data collection locally,
EMWIN data collection and retransmission, and a couple bigger web
sites.
Essentially - anything which is sent out over the
Unruh wrote:
[]
Apparently a number of Linux machines completely locked up at the leap
second. Problems in the kernel ntp.c code apparently.
Oh, that's interesting. Do you have any specific references? I haven't
looked at the source code, but I would have thought that ntp.c sounded
like a
Unruh wrote:
David J Taylor
david-tay...@blueyonder.neither-this-part.nor-this-bit.co.uk
writes:
Unruh wrote:
[]
Apparently a number of Linux machines completely locked up at the
leap second. Problems in the kernel ntp.c code apparently.
Oh, that's interesting. Do you have any
George R. Kasica wrote:
[]
I'd be happy to put it in here, but doing so with the Fedora Core 9
RPM based code is not something I'm familiar with.
I understand that perfectly.
I'm used to working
with straight source code for kernels ie make make install type steps
(don't take those
Richard B. Gilbert wrote:
[]
Last time, virtually the entire world screwed it up somehow. It took
the better part of twenty-four hours before everyone agreed once again
on more or less the same time!
I will be amazed if it's any better this time.
Yes, these were my notes at the time
Rob van der Putten wrote:
[]
I read that, during the previous leap second, in the countdown to the
new year on BBC TV, the last 'second' lasted two instead of one
seconds.
Regards,
Rob
With digital TV introducing several seconds delay, many people will be
celebrating the at the wrong
Richard B. Gilbert wrote:
[]
The leap second will be important to astronomers, navigators, the NIST
and a few other people and institutions.
Satellite operators - where the ground position of the satellite may
appear to vary by several kilometres where orbit data from before the
leap-second
Unruh wrote:
[]
The other problem is that the the voltage levels might be wrong. A
serial
port is supposed to be -12V to 12V, not the 0-5V that the PPS line on
the garmin delivers. Now some serial ports are OK with the 0-5V but
that is pretty
unusual. YOu either need a voltage converter,
George R. Kasica wrote:
[]
Next stepI added back GPS NEMA data without the gpsd daemon (I
don't pass the data out to anywhere so there's no real need for it)
and I see
# ntpq -p
remote refid st t when poll reach delay offset
jitter
Unruh wrote:
[]
Garmin defines the leading edge as the transition from 0V to 5V on
the PPS line. Now serial has two levels -12V and +12V. with
capacitive coupling, the garmin signal would be something like -2.5V
to 2.5 V which really is way out of spec for the serial port. (Or
with the
George R. Kasica wrote:
[]
And it does not report on the resulting time until the sentences
finish. Having just the one standard sentence would reduce that time.
How would I get that to occur? I don't see a way to cut down on the
data sent by the unit
Here's a snippet of the code I used
Steve Kostecke wrote:
On 2008-12-30, Unruh unruh-s...@physics.ubc.ca wrote:
David J Taylor david-tay...@blueyonder.co.uk writes:
I'm no expert! I don't see why my system picks up the PPS from just
the type 20 driver, and yours does not.
Because you have the PPS kernel patch installed
Unruh wrote:
David J Taylor
[]
With just the reference clock type 20, I get the accuracy needed.
The PPS line from the GBS-18 LVC is wired to the DCD line of the
serial port. In my ignorance, I don't see why you even need the SHM
driver, but as I said before, I'm no expert! I don't see why
Steve Kostecke wrote:
On 2008-12-31, David J Taylor david-tay...@blueyonder.co.uk wrote:
Steve Kostecke wrote:
The FreeBSD kernel does not need a PPS patch. One merely has to
specify the PPS option at compile time.
But the FreeBSD 5.3 I had did not include PPS, so that's presumably
why I
Unruh wrote:
[]
OK, I will believe you. However since the driving voltage of the
garmin 18 is usually taken from the USB and is 5 V, the output PPS
voltage will be less than 5V. ( maybe 4.5) Does that make a
difference?
In my experience, no. Anything above about 3V should be OK.
Taking an
Richard B. Gilbert wrote:
[]
I think your best help/advice will come from another GPS18LVC user.
I described my own simple setup here:
http://www.satsignal.eu/ntp/FreeBSD-GPS-PPS.htm
but it's not Linux, and I don't feel competent enough to give advice.
It seems likely that the wrong edge is
David J Taylor wrote:
Richard B. Gilbert wrote:
[]
I think your best help/advice will come from another GPS18LVC user.
I described my own simple setup here:
http://www.satsignal.eu/ntp/FreeBSD-GPS-PPS.htm
but it's not Linux, and I don't feel competent enough to give
advice. It seems
Unruh wrote:
[]
From reading the ntp docs, it seems that if you download the
leapseconds file, call it /etc/ntp.leapseconds and restart ntpd,
then ntpd will read that file, and set the leapsecond flag on your
system in the last month or day.
[]
This seems a lot simpler than the method
Unruh wrote:
David J Taylor
[]
In view of the popularity of the GPS18-LVC it's a pity that the
driver support for the leap second isn't better, but I appreciate
that being able to test once every few years doesn't make things any
easier!
As far as I can see, the GPS18-LVC unit does NOT warn
Martin Burnicki wrote:
[]
BTW, you can see if the leap file has been evaluated by running
ntpq -c rv
and checking the tai= value. The NIST leap second file does not only
contain information about the nearest leap second but also about all
earlier leap seconds and thus allows the NTP daemon
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