Subject: [Ietf-calsify] rrule question from draft-cstoner-rfc2445bis-00

From: PStephenson at gw.novell.com (Preston Stephenson)
Date: Thu Nov 17 09:02:54 2005

In section 8.3.5  Recurrence Rule, it states:
                                                           When used
with a recurrence rule,
   the "DTSTART" and "DTEND" properties MUST be specified in local
time
   and the appropriate set of "VTIMEZONE" calendar components MUST
be
   included.

I understand the MUST including the VTIMEZONE, but why is local time
required. Why can't it be UTC time also?

Thanks.
Preston

---

From: reinhold at kainhofer.com (Reinhold Kainhofer)
Date: Thu Nov 17 09:20:03 2005

> required. Why can't it be UTC time also?

Because Recurrence rules are highly time-zone dependent.
E.g. take an event that recurs very monday at 0:30 Central European Summer 
Time (UTC+2). If you shift the times to UTC, the event recurs at 22:30 every 
SUNDAY in UTC.

For weekly recurrences that RRULE might be adjusted to UTC, but e.g. if you 
have a recurrence every first monday of the month at 0:30 CEST, you can't 
express this in UTC any more at all (because the sunday before the first 
monday of a month is not necessarily the first sunday of the month).

Cheers,
Reinhol

- -- 
- ------------------------------------------------------------------
Reinhold Kainhofer, Vienna University of Technology, Austria
email: [email-masked], http://reinhold.kainhofer.com/
 * Financial and Actuarial Mathematics, TU Wien, http://www.fam.tuwien.ac.at/
 * K Desktop Environment, http://www.kde.org, KOrganizer maintainer

---

From: PStephenson at gw.novell.com (Preston Stephenson)
Date: Thu Nov 17 10:03:03 2005

I don't want to belabor the point.
I just want to make a couple of observations to see if I understand.
the problem from my point of view.

In our mail system, when a recurrence set is delivered,
we create all of the instances. We don't have one master
appointment and generate the instance on the day of the recurrence.
The start and end time will already be adjusted to be for the first
Monday of the month of each occurrence, then stored as Sunday 22:30
UTC.
This is the way that we will need to work for the time being.

The server stores start and end time in UTC.
It up to the client to adjust the time when it displays one of the
appointments
to the user.

I guess I can't see how the time stored on Sunday 22:30 UTC will not
be displayed by the client as the first Monday of the month 00:30
CEST.

Thanks.
Preston

> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
> 
> >                                                            When
used
> -
------------------------------------------------------------------
> -----BEGIN PGP SIGNATURE-----
> Version: GnuPG v1.4.2 (GNU/Linux)
> 
> iD8DBQFDfLu6TqjEwhXvPN0RAu01AKDIrRSebfNHpz/UVISom42YxrGP+gCfZQbl
> QmUAKqU4A3kNzlFSMla07Qw=
> =gfQu
> -----END PGP SIGNATURE-----
> _______________________________________________
> Ietf-calsify mailing list
> [email-masked] 
> http://lists.osafoundation.org/mailman/listinfo/ietf-calsify