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    Re: Time up for the leap second?
    From: Michael Dorl
    Date: 2012 Jan 17, 15:41 -0600

    On 1/17/2012 2:56 PM, Frank Reed wrote:
    >
    > You may reasonably imagine that this is easy and computers have it all
    > programmed in, but it's an illusion. Computer code for networking has
    > developed in an organic fashion. At the end of 2008, the folks who
    > manage Google's servers chose to skip the leap second in the proper
    > sense, and instead they inserted 1000 one-millisecond delays
    > (equivalent) during the course of the day on December 31, 2008. As
    > their official blog described it:
    > "The solution we came up with came to be known as the 'leap smear.' We
    > modified our internal NTP servers to gradually add a couple of
    > milliseconds to every update, varying over a time window before the
    > moment when the leap second actually happens. This meant that when it
    > became time to add an extra second at midnight, our clocks had already
    > taken this into account, by skewing the time over the course of the
    > day. All of our servers were then able to continue as normal with the
    > new year, blissfully unaware that a leap second had just occurred. We
    > plan to use this 'leap smear' technique again in the future, when new
    > leap seconds are announced by the IERS."
    >
    > -FER
    >
    
    
    Some years ago before the advent of computer networks, I discovered our
    local time as determined by 60 cycle clocks and wwv diverged during the
    day and then caught up in the wee hours of the morning.  It turned out
    that the local utility was turning out something less than 60 cycle
    power during the day probably because they were synced to the grid.
    Then when they disconnected from the grid, they turned out enough extra
    cycles to catch up with wwv.
    
    
    
    
    
    

       
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