[ntp:questions] DST 2007 handling via NTP?

Isaac Grover isaac.grover at gmail.com
Fri Jan 12 00:52:29 UTC 2007


Good evening from Wisconsin,

I just read about the DST changes that are going to affect all
date-oriented computing systems starting in March.  Specifically, I am
curious about the timestamps that NTP will hand out during the first
two weeks of March.

The way I understand the snippet below about the NTP protocol from
Wikipedia, NTP doesn't care about DST or time zones in general, so NTP
servers will continue to hand out sequential timestamps before, during,
and after the DST change goes into effect.  Am I correct in my
understanding?

The Wikipedia link:
http://en.wikipedia.org/wiki/Network_Time_Protocol#NTP_timestamps

And the snippet:

---8<---
The 64-bit timestamps used by NTP consist of a 32-bit seconds part and
a 32-bit fractional second part with an epoch of January 1, 1900,
giving NTP a time scale of 232 seconds (136 years) and a theoretical
resolution of 2−32 seconds (0.233 nanoseconds). Although the NTP
timescale wraps around every 232 seconds, implementations should
disambiguate NTP time using a knowledge of the approximate time from
other sources. Since this only requires time accurate to a few decades,
this is unlikely to ever be a problem in general use.

Even so, future versions of NTP will extend the time representation to
128 bits: 64 bits for the second and 64 bits for the fractional-second.
According to Mills, "The 64 bit value for the fraction is enough to
resolve the amount of time it takes a proton to pass an electron. The
64 bit second value is enough to provide unambiguous time
representation until the universe goes dim." Indeed, 2−64 seconds is
about 54 zettoseconds, and 264 seconds is about 585 billion years.
---8<---


Isaac Grover, Owner
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