On 2012-11-26 at 14:22 -0800, Steve Allen wrote:
On Mon 2012-11-26T13:10:03 -0800, Eric Fischer hath writ:
I'm no NTP expert so I'm not sure what it does differently, but the more detailed paper is at http://research.google.com/archive/spanner.html
In which it looks as if google has taken on the task of creating its own global time scale (a task previously only attempted by national governments and international agencies) and that the "leap smear" is implemented as part of that time scale.
Leap smear was implemented while Google used NTP; Chris Pascoe described it publicly in: http://googleblog.blogspot.com/2011/09/time-technology-and-leaping-seconds.h... A while back, I patched up the OpenNTPd sources with code from FreeBSD and wanted to get around to implementing leap seconds handling, which OpenNTPd didn't do. I didn't get time to do so, but did document my understanding of the issues and the approaches: https://github.com/syscomet/openntpd/blob/master/LeapSeconds.md Note though, as I describe in that document, smear only works in a closed community of timeservers, because of the lie introduced on the wire; for open Internet usage, something like UTC-SLS is needed instead. In all this, the closest relationship there is to time _zones_ is that there's a similar problem of distributing a file of offsets to be used by all systems handling time. Instead of the Olson TZ DB, it's the IERS leap-second jumps. -Phil