KEP2: Modification of datetime type, introduction of 'tz' sub-tag (wiki revision 10645 of 2010-11-19)

Joon Radley joon at
Mon Dec 20 14:40:45 CET 2010

On 20 Dec 2010, at 12:11 PM, Hendrik Helwich wrote:

>> Canonically storing "UTC calculated from standard time" solves both, but
>> for the second case the chance of bad results is just very tiny, whereas in
>> the first case we're guaranteed to be wrong half the year - always the
>> other one from when the event was created.
> i think it is not nice to store a wrong UTC time half the year. This is 
> complex and can confuse people.
> Also technically it is possible that the standard time changes for a time 
> zone. This would break the hole concept.
> I am not sure if this could happen in practice but from the format it is 
> possible.
> So if already a wrong UTC time is stored half the year it could also be stored 
> wrong for the hole year by storing directly the local time as UTC. This will 
> be less error-prone.

How can UTC be wrong? Any conversion to UTC that give the wrong UTC needs to be re-implemented. (Visa versa is also true).

Best Regards

Joon Radley

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