[time-nuts] June 30 2015 leap second

[d0ct0r]

Today, I did the check the settings for my BC637 card. I was surprised 
that its overwrite my manual setting for the Leap Event by following 
information:

Time Settings:

  Mode                           : GPS
  Time Format                    : Binary
  Year                           : 1995
  Local Offset                   : 0.0
  Propagation Delay              : 0
  Current Leap Seconds           : 16
  Scheduled Leap Event Time      : 876614400
  Scheduled Leap Event Flag      : Insertion
  GPS Time Format                : UTC Format
  IEEE Daylight Savings Flag     : Enable


"Sun, 12 Oct 1997 00:00:00 GMT". Its weird. I am going to re-insert it 
and will check it again later.

New Time Settings are:

  Mode                           : GPS
  Time Format                    : Binary
  Year                           : 2015
  Local Offset                   : 0.0
  Propagation Delay              : 0
  Current Leap Seconds           : 16
  Scheduled Leap Event Time      : 1435708799
  Scheduled Leap Event Flag      : Insertion
  GPS Time Format                : UTC Format
  IEEE Daylight Savings Flag     : Enable

Also, my NTP, which rely on that card,  didn't get the value for leap 
second event yet:

# ntpq -c rv

associd=0 status=0028 leap_none, sync_unspec, 2 events, no_sys_peer,
version="ntpd 4.2.6p5 at 1.2349 Mon Sep 22 20:41:39 UTC 2014 (14)",
processor="x86_64", system="Linux/3.2.0-74-generic", leap=00, stratum=1,
precision=-23, rootdelay=0.000, rootdisp=8248.907, refid=BTFP,
reftime=d85e7526.957a1b17  Mon, Jan 12 2015 11:30:30.583,
clock=d85ec544.e1effe31  Mon, Jan 12 2015 17:12:20.882, peer=0, tc=4,
mintc=3, offset=3.757, frequency=-243.698, sys_jitter=0.000,
clk_jitter=1.328, clk_wander=15.616


Regards,
Vlad

> 
>> It's fragile enough that there have been accidental false leap-second 
>> events.
> 
> Yes, for example if there have been GPS receivers which decoded the
> UTC parameters incorrectly, and started to announce a leap second when
> there wasn't one (end of September).
> 
> That's why, for example, ntpd's leap second handling code has been
> changed in v4.2.6 to accept a leap second warning only if the warning
> is received from a majority of the configured servers.
> 
> If you want to be sure you can also provide ntpd with a leap second
> file which is then (in current versions) considered as authentic
> source for leap second information.
> 
> Martin
> 
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-- 
WBW,

V.P.