On Jul 9, 2012, at 7:41 AM, Rob Seaman wrote:

> On Jul 9, 2012, at 5:24 AM, Gerard Ashton wrote:
> 
>> I just read an explanation of what went wrong with some Linux systems:
> 
> Yes, that and the Landslide analysis are very good.  I also found PHK's 
> comments on leapsecs to be illuminating from the FreeBSD perspective.
> 
>> It would be tempting to prepare for the next leap second by running a fake 
>> leap second into a test system that is sitting in a lab doing nothing but 
>> keep time. But a realistic test requires that the system under test be 
>> running a load as similar as possible to production systems.
> 
> Whatever else is true, it's clear that insufficient testing occurred.  As Y2K 
> lead for my group I kept a system set ahead to a date in the 2000's for a 
> couple of years beforehand.  Plus 11 years I think it was, since the 
> 2010/2011 New Year's Eve resembled the Millennium (day of the week, preceding 
> year not a leap year).  This permitted innumerable tests in advance.
> 
> The corresponding leap second tests are different, but the need to test edge 
> cases is similar.  Here it doesn't look like a serious attempt was made even 
> to test the basic functioning (not on loaded systems certainly).
> 
> It is quite likely that another leap second will occur before 2015; it is a 
> near certainty there will be multiple such before 202N when any change would 
> take effect.  Putting aside our diverse policy positions, members of this 
> mailing list have worked for many years to raise the profile of UTC issues.  
> Perhaps this will be easier now, and we should be able to identify common 
> cause in encouraging such testing, and in general in educating various 
> communities about timekeeping issues.

The biggest problem with leap seconds is the attitude "Well, it is only a 
second, I don't have to worry about getting it right." Turns out, getting them 
wrong can have worse effects than things being off by a second.  Summarizes a 
key point I've been making for years...  Leap seconds are hard, so no body 
bothers to get them right...  I get shot as the messenger, when really the 
problem is much more deeply engrained in the computer community.

Warner

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