[ntp:questions] Timekeeping broken on Windows XP with multimedia timer enabled (-M option)

David Lord snews at lordynet.org
Tue Jan 26 12:25:09 UTC 2010

David J Taylor wrote:
>>> <http://www.veracityuk.com/products/timenet/timenet.php>
>>> <http://www.veracityusa.com/products/timenet/timenet.php>
>> <http://www.gpsntp.com/economic-ntpserver/>
> Thanks, most interesting - I knew about neither of those products.
> http://www.veracityuk.com/products/timenet/timenet.php
>  "Accuracy: Ethernet NTP ±100ms overall" is not what I call "good 
> timekeeping".
> http://www.gpsntp.com/economic-ntpserver/
>  "NTP time stamp resolution: +/- 15 usec" - nice that it has SNMP, but 
> no specification of accuracy!
> You can't buy directly from either site, which discourages an impulse 
> purchase.
> I already have the GPS, and was looking for a simple computer (small and 
> low-powered) where I could run a FreeBSD or similar system.  Will see 
> what emerges from the router or David Lord's approaches.

I've moved away from using ntp over ethernet as main method
for keeping systems in sync. Network and system load along
with temperature variations cause relative havoc which I'll
see if I can cure using pps from the radioclock. It could
be possible to stabilise system clock oscillators but I'm
not sure if that is effective or practical on modern pcs and
it really involves too much work vs pps via parallel port
(last system I purchased has neither serial nor parallel).

The ADM5120P may become base for generating a pps signal to be
distributed around network via rs422 and possibly 433MHz tx/rx
if that doesn't add too much variation. I'm not sure my
programming skills are up to this though.

I also have a 486dx with a very stable (at least long term)
crystal but lacking ram (I still have another 3x 486 but only
40MB ram total to split between four pcs).

My order for some D25 connectors from CPC turned up on Friday,
D25 hoods + all the extra items I'd added to take value up to
give free delivery, but stock discrepancy and no D25 bodies.
Anyway I had a search through my rubbish last night and found
a couple of connectors.

Meanwhile due to cold weather I've had heating turned up and
server using Conrad MSF receiver has had periods of much
reduced offsets (< 300us), so suspicion that the ttl out from
Conrad is on borderline for the rs232 on that server seems
confirmed and I'll give parallel port method a try on a
different system later this week.


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