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RE: 24:00:00 allowed or not

From: Ashok Malhotra <ashokma@microsoft.com>
Date: Thu, 12 Dec 2002 05:15:33 -0800
Message-ID: <E5B814702B65CB4DA51644580E4853FB03E9FF77@red-msg-12.redmond.corp.microsoft.com>
To: "Schluter, Paul (MED, GEMS-IT)" <Paul.Schluter@med.ge.com>, "W3C XML Schema Comments list" <www-xml-schema-comments@w3.org>

As the attached note says 24:00:00 is allowed.  But it also says that it
an alternate representation for 00:00:00 (of the following day).  This
is not what you want.  In the presence of a leap second you want
24:00:00 to be the final second of the current day and 00:00:00 the
following second of the next day.  We need to craft some careful wording
to cover this situation. 

All the best, Ashok

-----Original Message-----
From: Schluter, Paul (MED, GEMS-IT) [mailto:Paul.Schluter@med.ge.com] 
Sent: Wednesday, December 11, 2002 4:59 PM
To: W3C XML Schema Comments list
Subject: RE: 24:00:00 allowed or not

Wednesday, December 11, 2002,

Ashok and James,

I noticed this thread in the W3C email archives regarding
whether 24:00:00 should be allowed or not.  It _must_ be
allowed, because the time "24:00:00" can actually exist
when a leap-second is inserted at midnight.

Leap-second insertion typically occurs every 18 months or
so, principally to account for the gradual slowing of the
earth's rotation over time (roughly 1.7 msec/day/century).
Leap seconds are supported by NTP (RFC-1305) and SNTP (RFC-2030)
and are recognized in numerous other areas such as astronomy
where accurate timekeeping is required.


Paul Schluter

Date: Tue, 23 Apr 2002 06:40:06 -0700
From: "Ashok Malhotra" <ashokma@microsoft.com>
To: "James Clark" <jjc@jclark.com>, <www-xml-schema-comments@w3.org>
Subject: RE: 24:00:00 allowed or not?

24:00:00 is allowed.  It is an alternate representation for 00:00:00

All the best, Ashok

-----Original Message-----
From: James Clark [mailto:jjc@jclark.com]
Sent: Tuesday, April 23, 2002 6:19 AM
To: www-xml-schema-comments@w3.org
Subject: 24:00:00 allowed or not?

ISO 8601 section 5.3.2 allows 24:00:00 as a representation of midnight.
Appendix D of XML Schema Part 2 says that the hh field runs between 0
and  23, but there is no mention of 24:00:00's not being allowed as a
difference  between XML Schema and ISO 8601.  I'm left uncertain as to
whether 24:00:00 is allowed or not.

Received on Thursday, 12 December 2002 08:16:00 UTC

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