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Re: Draft for review: Working with Time Zones

From: John Cowan <cowan@mercury.ccil.org>
Date: Tue, 8 Feb 2011 09:49:58 -0500
To: Richard Ishida <ishida@w3.org>
Cc: www International <www-international@w3.org>
Message-ID: <20110208144958.GA18028@mercury.ccil.org>
Richard Ishida scripsit:

> Comments are being sought on a new draft[1] of the W3C Note "Working  
> with Time Zones" [2] prior to final release. The new document provides  
> guidelines and best practices for working with time and date values and  
> how time zones affect applications and document formats.

There is absolutely no mention of leap seconds, and there are statements

> For example, the Java type java.util.Date is a long (integer) value. It
> represents the number of milliseconds since 00:00 (midnight) on January
> 1, 1970 in UTC. 

which are absolutely false.  The truth is that a java.util.Date represents
the number of milliseconds since the Epoch *after all leap seconds have
been discarded*.  This is a very different thing.  Any application that
attempts to measure time across one or more leap seconds using Posix
timestamps will get the wrong answer.

It's essential that this be rewritten to take leap seconds into account,
as they say, early and often.  Either that, or all talk of incremental
time must be banished.

Knowledge studies others / Wisdom is self-known;      John Cowan
Muscle masters brothers / Self-mastery is bone;       cowan@ccil.org
Content need never borrow / Ambition wanders blind;   http://ccil.org/~cowan
Vitality cleaves to the marrow / Leaving death behind.    --Tao 33 (Bynner)
Received on Tuesday, 8 February 2011 14:50:25 UTC

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