[ntp:questions] Re: Oncore leap second bug at 11/29/2003 62:28:15

Jens Rosenboom jens.rosenboom at freenet-ag.de
Sat Nov 29 11:06:10 UTC 2003

"Tom Van Baak" <tvb at leapsecond.com> writes:

> Sure enough, the Oncore 256 week leap second
> bug showed up as predicted by Motorola. It was
> a little different than we thought; this is how an
> Oncore VP GPS receiver reported time yesterday:
> 11/27/2003 23:59:58
> 11/27/2003 23:59:59
> 11/29/2003 62:28:15
> 11/28/2003 00:00:00
> 11/28/2003 00:00:01
> If any of you saw NTP anomalies I'd be interested
> to hear about them. Presumably the invalid hour
> saved the day (the time stamp would be rejected).
> For details see:
> http://www.leapsecond.com/notes/leapsec256.htm
> /tvb
> http://www.LeapSecond.com

Our Stratacom GPS clocks also seem to have been affected, but not
now, but already 4 weeks earlier! On 11/01/2003 00:00:00 they started
setting the "leap second ahead" indicator in the time string output,
which in itself would have been too bad.

The bad thing was, that this action seems to have taken so much of
their available CPU power, that the rate at which the timestrings
(which were still being output once per second) were updated to the
correct time, dropped from once per second to about twice per minute.

The obvious result being ntpd loosing sync on the GPS as prefer peer
and disabling PPS, which otherwise would have continued correctly.

We have four receivers, all did exactly the same thing, and they got
back to normal only after power cycling them.

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