[ntp:questions] Experimental ntpd for Windows

Danny Mayer mayer at ntp.isc.org
Sun Feb 1 19:30:29 UTC 2009


Dave Hart wrote:
> On Feb 1, 9:09 am, ma... at ntp.isc.org (Danny Mayer) wrote:
>> Dave Hart wrote:
>>> I didn't say no one ever uses timeBeginPeriod to raise the multimedia
>>> timer precision on a server.  I said it is reasonable to know a
>>> particular server will not run any software which raises the
>>> multimedia timer precision.  If, on the other hand, you know you do
>>> use such software, or you can't be sure what software will be run, -M
>>> with the experimental ntpd is wise with Vista and WS2008.
>> No, that's not correct. You cannot make any assumptions whatsoever as to
>> what the system may be running.
> 
> I most certainly can make assumptions about what my system may be
> running, your orders notwithstanding.
> 
>> It is a fallacy to assume that any admin
>> or user will have any idea what any applications will be doing with the
>> multimedia timer or any other code that affects the clock.
> 
> BS.  I know exactly what runs on my servers, and alone decide.  I am
> an admin or user.  Your blanket assertion is wrong.  If they don't
> know, the safe choice (and the Meinberg installer's default) is to use
> -M.
> 
>> Furthermore
>> as new applications get deployed with as a pure user application or as a
>> server application you have no idea what its requirements might be. ntp
>> is founded on the principal that the system clock needs to be correct no
>> matter what the system or network is or is not doing.
> 
> Run with -M.
> 
>> I don't have the time right now to analyze your changes but you need to
>> ensure that this works on a large variety of systems in a large variety
>> of environments.
> 
> As I've stated repeatedly, it's better than what we have now.  Now
> interpolation is used unconditionally.  With my change, it is avoided
> if the scenario that breaks it is detected (fine-grained system
> clock).  On Vista and later, with -M, it always detects that breakage
> and disables interpolation.  There is no regression, only forward
> progress.

Sorry, you misunderstand what I meant. What you do personally is up to
you. However, what goes into the ntp project I do have a say. I
appreciate your efforts and would be happy to incorporate your suggested
changes into ntp, but it needs to follow the guidelines.

Danny



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