[tz] Turkey to delay DST

David Braverman david at braverman.org
Fri Feb 28 13:19:10 UTC 2014

Allow me to revise and extend my previous remarks.

*Schedule* to wall-clock time; *log* to UTC.

As long as we few, we proud, we time zone geeks are on the job, we'll most likely be able to convert past UTC times to whatever local time actually showed up on wristwatches. But it's more important in an _event log_ that we record an unambiguous point in time.

Otherwise I totally agree using wall-clock time for putting things on people's calendars. In fact, from comments subsequent to my post I think one actually needs to have an interpolating entity between the scheduled event and each the participants:

*Event* has: organizer local start time, UTC start time, organizer local end time, UTC end time, organizer local time zone, event details

*Participant* has: time zone, person details

*Event-Participant* has: event ID, participant ID, event local start & end times, time zone

That way, changes to a participant's time zone rules wouldn't affect any other participants. Changes to the organizer's time zone rules would affect all participants. It is left to the implementer to determine when these time zone rules have changed, and apply them to the participants' start and end times.


David Braverman

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