[time-nuts] Is it sensible to update every few seconds from NTP server?

[David]

Some finicky software becomes upset if time is stepped backwards too
far.

I have seen PC hardware clocks that drifted 30 seconds a day but that
only matters during a restart.  The more common problem involves OS
time drift, often amounting to seconds per minute, caused by bad
System Management Mode code leading to lost interrupts or other
problems.  A BIOS update or fiddling with the CPU power management
usually fixes that.

On Wed, 7 Nov 2012 17:11:26 -0500, paul swed <paulswedb at gmail.com>
wrote:

>Interesting I am unaware of any amateur service requiring that tight of
>a timing relationship.
>At least modern PC clocks do not drift that badly in a few minutes. So it
>is pretty odd.
>Without further detail I am at a loss for why you need to do that.
>Maybe he is tinkering with spreadspectrum?
>Regards
>Paul
>
>On Wed, Nov 7, 2012 at 5:04 PM, David <davidwhess at gmail.com> wrote:
>
>> Some Windows NTP clients like Tardis can calculate and implement a
>> clock frequency adjustment instead of stepping the clock if the time
>> adjustment is below a specified limit.  If he was using an application
>> that was upset by the time being stepped, then that might allow less
>> frequent updates.
>>
>> If he is polling that often to maintain accurate time, then I would
>> assume he is using a local known to be accurate NTP server.
>>
>> There are Windows NTP clients which will synchronize to GPS PPS time.
>> That should be better than stock hardware and Windows can handle
>> anyway.  Something like a Garmin GPS18 is specified to be within 1uS
>> and has a pulse to pulse jitter in the 10s of nanoseconds.
>>
>> On Wed, 7 Nov 2012 21:41:36 +0000, David Kirkby
>> <david.kirkby at onetel.net> wrote:
>>
>> >Someone at my radio club uses some mode of operation where accurate
>> >time is required. He said the standard Windoze clock does not keep
>> >sufficiently accurate, so he has software which updates from an NTP
>> >server every 4 seconds or so. It's not exactly a denial of service
>> >(DOS) attack, but seems almost close to it in NTP terms to me. I can't
>> >really believe updating every few seconds is sensible myself, but he
>> >assures me it works very well. (I'm rather hoping it does not use a
>> >stratum 1 server!)
>> >
>> >I'm sure someone will say if you want accurate time on a PC, to use
>> >some combination of GPS, rubidium or OCXO with a 1 pps pulse and a
>> >serial port on a FreeBSD or similar computer. But that's probably not
>> >practical if your software only works on Windoze.
>> >
>> >Any comments?
>> >
>> >Dave, G8WRB.
>> >
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