Ry wrote:
Here's the actual link:
http://research.microsoft.com/users/misard/papers/aes2004.pdf
Basically, the MS guys moved most everything into a kernel mode driver
and alter NTP to poll every 4 seconds. No problem for their
application, since all devices are on the same LAN as the master audio
clock. I can't decide if the ±50µs accuracy is impressive or not...
but obviously they wouldn't have modified NTP so heavily if it would
have met the application's needs out of the box.
They have solved two core problems:
1) The Microsoft kernel clock has approx 10 ms resolution, which is far
too coarse.
2) Packet processing latency variations impact short-term stability.
They also claim to have invented 'burst' mode, i.e. they send 5 packets
during each polling period and select the median. :-)
If the kernel timestamping and improved OS clock resolution is or could
become available in a standalone driver, then this would represent a big
boost for Windows-based NTP servers.
In fact, they could eventually provide comparable performance to FreeBSD
running on the same HW! :-)
Terje
--
- <[EMAIL PROTECTED]>
"almost all programming can be viewed as an exercise in caching"
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