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Re: Draft for review: Working with Time Zones

From: Chris Lilley <chris@w3.org>
Date: Wed, 9 Feb 2011 13:11:27 +0100
Message-ID: <1952674509.20110209131127@w3.org>
To: John Cowan <cowan@mercury.ccil.org>
CC: "Phillips, Addison" <addison@lab126.com>, Richard Ishida <ishida@w3.org>, www International <www-international@w3.org>
On Tuesday, February 8, 2011, 5:49:22 PM, John wrote:

JC> Phillips, Addison scripsit:

>> > It's essential that this be rewritten to take leap seconds into
>> > account, as they say, early and often.  

>> Well, once or sometimes twice a year in certain years :-).

JC> Current provisions allow for a leap second at the end of any month,
JC> actually, and by the year 158421, we'll have to have a whole hour worth
JC> of leap seconds every day.

To put this in context; how many leap seconds have there been since the Jan 1970 epoch?

In other words, if two date-times are subtracted, one from now and one right at the epoch, without accounting for leapseconds, what is the total error currently?

OK, answering my own question
http://en.wikipedia.org/wiki/Leap_second

24 seconds.

And the time from atomic clocks differs from UTC by an additional 10 seconds, apparently.

So the total error from ignoring this is half a minute and counting.

-- 
 Chris Lilley   Technical Director, Interaction Domain                 
 W3C Graphics Activity Lead, Fonts Activity Lead
 Co-Chair, W3C Hypertext CG
 Member, CSS, WebFonts, SVG Working Groups
Received on Wednesday, 9 February 2011 12:11:31 GMT

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