[time-nuts] Timing performance of servers

Don Latham djl at montana.com
Thu Oct 25 13:03:11 EDT 2012


Look out for TNC connectors and 12v on the Symmetricons!
Don

Bob Camp
> Hi
>
> If:
>
> 1) You are in a reasonable location (good sky view)
> 2) Don't have a great long cable run (< 50')
> 3) Are only after NTP time
>
> Then, you can get away with a pretty simple antenna. I likely won't last
> as
> long as a better one out in the weather though. If you shop the auction
> sites you can get reasonable antennas (Lucent / Trimble / Syneregy)  for
> <
> $30.
>
> Bob
>
> -----Original Message-----
> From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
> Behalf Of Sarah White
> Sent: Thursday, October 25, 2012 12:44 PM
> To: Discussion of precise time and frequency measurement
> Subject: Re: [time-nuts] Timing performance of servers
>
> On 10/24/2012 6:47 PM, Magnus Danielson wrote:
>> Fellow time-nuts,
>>
>> When spending time on a conference last week, I heard one interesting
>> comment that they lost data due to bad timing on their Windows
>> servers.
>>
>> Now, I know that the standard Windows uses SNTP in order to achieve
>> the
>> goal of having the timing of the machines sufficiently aligned to
>> allow
>> Kerberos authentication. SNTP suffice for that, as it needs to be a
>> handful of minutes in line.
>>
>> If you need better performance than that, you should use NTP (and then
>> download and install Meinbergs Windows-client for NTP).
>>
>> Then again, I would point out that for this type of data, it would
>> most
>> probably be better served on a Linux box.
>>
>> What should be a nice wake-up call for them would be a summation of
>> how
>> different strategies would give them clock precision of sufficient
>> grade. So, does anyone know of such measurements presented anywhere?
>>
>> There are bits and pieces, but the ideal for this case would be if
>> they
>> where collected in one page/paper.
>>
>> This is an awareness thing, so that people can do a little more
>> well-informed choices.
>>
>> Cheers,
>> Magnus
>
> 1)
>
> Thanks magnus. This is something I'm quite interested in:
>
> I'm not the only one doing testing for Microsoft NT 5.x and higher
> against NTP-type synchronization. It's actually high enough quality such
> that a Windows server running NTP with a refclock provides significantly
> better time than the public NTP servers.
>
> Here are a few writeups I've been using for reference, and I've been
> testing and duplicating some of the listed configurations, hoping for my
> own writeups:
>
> http://www.satsignal.eu/ntp/NTP-on-Windows-Vista.html (basic timing)
>
> http://www.satsignal.eu/ntp/NTP-on-Windows-serial-port.html (connected
> to refclock, timing was better than 50 microseconds jitter, averaging
> less than 10 microseconds)
>
> Am actively in the process of getting everything to replace my own
> "navigation" GPS refclock with a timing mode one. At this point I just
> need to find a good antenna...
>
> 2)
>
> ... Changing subject slightly:
>
> Regardless of if I run linux vs bsd vs windows (will be testing multiple
> configurations of each, and doing writeups over the next few years as I
> test more and learn) I'll need a good external antenna for the new GPS
> I'm going to run.
>
> Anyone think I can get by with anything cheaper than a symmetricom
> 58532a antenna? I can probably get one (used) for less than $50 on ebay,
> but I'd really prefer to source something more entry-level for closer to
> $5 or $10 if possible. Any suggestions?
>
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-- 
"Neither the voice of authority nor the weight of reason and argument
are as significant as experiment, for thence comes quiet to the mind."
De Erroribus Medicorum, R. Bacon, 13th century.
"If you don't know what it is, don't poke it."
Ghost in the Shell


Dr. Don Latham AJ7LL
Six Mile Systems LLP
17850 Six Mile Road
POB 134
Huson, MT, 59846
VOX 406-626-4304
www.lightningforensics.com
www.sixmilesystems.com






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