Re: [c-nsp] NTP Servers

[Grant Ridder <shortdudey123 () gmail com>]

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 () 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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