[CentOS] leap second

Mon Jul 2 16:24:23 UTC 2012
Peter Eckel <lists at eckel-edv.de>

Hi Les, 

> I'm sort of curious about how a bug of this magnitude slips through
> the QA process (into java and RHEL, not CentOS).  With all the furor
> about y2k, did no one even bother to simulate a leap second ahead of
> the real occurrence?

... and leap seconds are not even scarce. According to <http://en.wikipedia.org/wiki/Leap_second>, this was the third one since 2000, and it is actually the first time I heard of any problems. 

On the other hand I'm a bit surprised that the problems were comparably few - actually there is a time '01:59:60' for one second, and any plausibility check I've ever seen assumes that minutes and seconds are in the range from 0..59. Wrongly, it seems.

Apparently Google uses an approach that looks much less risky to me - they use a time window over which they 'smear' the leap second by making their time servers lie about the time for a while, making it pass a little bit slower. That way they avoid the unlucky 61st second and still advance the clocks within a reasonable time. 


Kind Regards,