[ntp:questions] Trying to use Dimension 4 time keeper

W. eWatson wolftracks at invalid.com
Sun Sep 15 17:08:27 UTC 2013


On 9/14/2013 11:53 PM, David Taylor wrote:
> On 14/09/2013 21:39, W. eWatson wrote:
> []
>> A little bit of data from the two XP PCs:
>> Older and more troublesome PC
>>   Jitter high 300-650
>>   Offset around 685
>>   Delay about 100.xxx
>>   Reach 80  jumped to 377 an hour later
>>   One * for the single pool
>>
>> Newer XP
>>   Jitter low, 11-8
>>   Reach 377
>>   * + - + - on five servers
>>   Delay 100-150
>>
>> Those are fairly rough, as seen in a five minute span. To really make
>> any progress I would think a monitor of the data would be more helpful.
>>
>> I noticed Broken Clock in the documentation mentioned above. It looks
>> tricky to evaluate.
>>
>> In my situation, I would be happy if one of the important parameters
>> would sound an alarm in my den when one went out of bounds. Fat chance
>> of that.
>
> How are you connected to the Internet?  Let's start with your newer PC.
>   The delay of 100-150 ms is much higher than I would expect for a
> direct "fast" Internet connection, it sounds more like dial-up.  If you
We use AT&T DSL. My wife has noticed at time, the speed has been slow; 
however, I would expect the newer PC to have time failures. As I wrote 
somewhere, the newer PC is mostly off, so I'll keep it on for several 
weeks to see if the problem shows there.

> are using the "pool" directive as I suggested (NTP 4.2.6p5 required), I
> would expect to see more than five servers listed.
I have 4.2.7p5 on the older PC. The five are on the newer PC. Since it 
seems to hold time OK, I've left it that way. The pooled idea is on the 
older PC.
>
> You can monitor by enabling the statistics collection within NTP, and by
> using MRTG as explained on my Web site:
>
>    http://www.satsignal.eu/ntp/NTPandMRTG.html
>
> If statistics are enabled, both Meinberg and I offer plotting programs:
>
>    http://www.meinbergglobal.com/english/sw/ntp-server-monitor.htm
>    http://www.satsignal.eu/software/net.htm#NTPplotter
>
> The "Broken clock" problem may manifest itself by NTP reporting that it
> is stepping the clock, or even giving up.  Look for NTP entries in the
> event log to monitor this.
>
> To get alarm monitoring, you could use SNMP (although that's not yet in
> the Windows port of NTP), or you could write a small Perl script to be
> run once every few minutes by the Task Scheduler, which checked the
> parameters you want to monitor by running the appropriate ntpq command,
> and which then sounded the alarm as required.  The alarm could be a wave
> file which you play - perhaps even inside the Perl script.
>
> I have Perl script examples on my Web site at the first URL I gave, and
> there is information here:
>
>    http://www.xav.com/perl/site/lib/Win32/Sound.html
>
> on playing .WAV files with Perl in Windows.  Sounds like a good Autumn
> project!
>
> Having said all of that, my situation a decade back was similar to yours
> - wanting to have several Windows PCs well synced.  Were I to be
> tackling the same problem today, I would spend less than US $50 on a
> Linux PC (Raspberry Pi) and sync it to my Internet sources, and then
> sync the Windows PCs to the Raspberry Pi (using a much shorter poll
> interval, 32 seconds, maxpoll 5).  If the location had GPS available
> (e.g. near a window with a sky view) I would spend approx. US $100
> instead and add an Adafruit GPS to the Raspberry Pi, making a unit known
> to correct to a few microseconds, and sync my Windows PCs to that (with
> a "pool" directive for backup).
Well, thanks for the help, but this problem is beyond me. The 
organization that sponsors the science effort is remiss in providing 
some solution.

Unfortunately, the problematic PC has produced a new problem. A few 
weeks ago I decided to check the PC battery. In doing so I had to take 
out a graphics card and a video grabber card to get to the battery. I 
found the battery in good shape, and put everything back together. 
Several days later I found the PC beeping. Subsequently, I found that 
the beeping began from around five minutes to maybe an hour after I had 
logged in, possibly as long as a day. The science s/w was put into play 
immediately after logging in. I figured it was heat, but that idea 
pretty much fizzled. I need to check the power supply to see if it 
somehow gone bad.

As a last resort to the timing problem, I might bring the PC into my den 
and see if the timing is still flaky. This is no longer a high priority 
issue. I'll pick at it as I can.



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