[c-nsp] NTP Servers
Grant Ridder
shortdudey123 at gmail.com
Sat Jun 30 22:42:42 UTC 2012
I don't understand why anyone would use windows server for anything that
needed precision like time.
On Sat, Jun 30, 2012 at 5:39 PM, Keith Medcalf <kmedcalf at dessus.com> wrote:
>
> > Or you can ask the it guys to use a windows server... Eg:
> >
> > http://support.microsoft.com/kb/816042
>
> That is a joke Jared? You left off the smiley.
>
> Windows doesn't do NTP out-of-the-box (Microsoft assertions to the
> contrary notwithstanding). You can build a reasonably working standard
> daemon, however don't expect time to be very accurate. Windows
> out-of-the-box can keep time +/- 10 minutes or so using the Microsoft
> lets-pretend-NTP.
>
> You can build the current standard NTPD distribution on Windows. You can
> also spend lots of time to make it "work as well as possible" (once you
> manage to get it to compile, that is). Even so, when you have configured
> it to the optimality of accuracy, this is what you can expect:
>
> remote refid st t when poll reach delay offset
> jitter
>
> ==============================================================================
> +tic.nrc.ca .PPS. 1 u 13 64 377 55.544 5.913
> 0.870
> -tac.nrc.ca .ATOM. 1 u 48 64 377 56.188 4.768
> 3.041
> -toc.nrc.ca .ATOM. 1 u 1 64 377 55.485 4.758
> 0.981
> +tick.usask.ca .GPS. 1 u 34 64 377 19.566 6.942
> 5.699
> *tock.usask.ca .GPS. 1 u 29 64 377 19.665 5.955
> 1.937
> -clock.isc.org .GPS. 1 u 37 64 377 53.091 8.311
> 0.649
> +clock.sjc.he.ne .CDMA. 1 u 48 64 377 43.591 6.066
> 2.501
>
> offset: 0.005955 s
> frequency: 23.346 ppm
> poll adjust: -30
> watchdog timer: 47 s
>
> is about the best you will get. Statistics are pretty awful:
>
> Date # O.Avg O.Median O.Range O.CI O.Skew
> O.Kurt F.Avg F.Median F.Range F.CI F.Kurt
> 2012-01 899 0.765559 0.004198 20.05221 0.000371 -0.56023
> 0.751151 21.31698 20.9705 2.9685 0.108050 -0.88068
> 2012-02 9673 0.237434 -7.46502 59.75607 0.000156 -1.43583
> 8.609085 19.01126 19.3495 5.2995 0.040683 -0.54578
> 2012-03 1380 -0.02157 -14.8416 44.00043 0.000124 -1.08589
> 4.559049 18.08941 16.822 7.536 0.045387 0.268831
> 2012-04 1322 0.196654 21.16261 106.1250 0.000141 -0.48643
> 26.05868 17.56811 16.812 6.111 0.040561 -0.38021
> 2012-05 8849 0.118125 27.44213 72.01526 0.000161 0.296114
> 8.939429 17.88685 15.2595 9.3195 0.080186 1.121740
> 2012-06 1457 0.409662 -20.2809 63.32684 0.000114 -1.44144
> 11.98237 20.50724 19.5425 6.7425 0.042372 -0.08891
> 6102 0.201651 21.16261 106.1250 6.065429 -0.84354
> 13.78161 18.71838 16.1125 10.1725 0.023443 1.215941
>
> This is from a custom ntpd build using the highest precision that it can
> manage to coerce from Windoze.
>
> Of course, this may be accurate enough for most uses -- at least it does
> not have to time-step.
>
> Doesn't compare to ntpd on linux on an 80286 with 640K ram booting from a
> floppy, which can maintain time sync within less than 1 ms easily.
>
> ---
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>
>
>
>
>
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