Timezone needed?

Joon Radley joon at radleys.co.za
Wed Jun 30 06:54:45 CEST 2004

Hi Bernhard

> I guess it is not necessary to completey use the XML format 
> to show the principal question, pseude code should do it.
> Recurring event, saved as:
> 	Subject: Team gathering
> 	Recurring: Every first monday
>         Time: 9:30  Timezone: Europe/Berlin
> So the client know that this is 8:30 UTC in January and 7:30 
> UTC in July and will show the appointments there.

I actualy want to see how you will encapsulate the information into data
that I can parse.

In pseude code UTC will work like this

Recurring event, saved as:
	Subject: Team gathering
	Recurring: Every first monday
        Time: 7:30 UTC
The client will translate from UTC to local time (OS knowing about daylight
savings time) and display the appointment as 9:30 (Europe/Berlin )in January
and 9:30 (Europe/Berlin) in July.

You are looking from the point of view that when daylight savings time kicks
in the definition of UTC changes. UTC does not change, your time _zone_
changes and this will reflect when you translate from UTC to local time.

UTC is always the same for everybody all the time.

> > > Also please show me how this must be handled if the 
> appointment is 
> > > created in another time zone for this example. (E.g The CEO makes 
> > > the entry while in South Africa (using the CAT as local time), to 
> > > reoccur in Germany (using CET with and without daylight 
> savings) on 
> > > his return )
> RFC2445 nicely descripes that floating times can have its 
> uses, too, but this is outside of my remark. I also believe 
> that floating times can become a hassle in implementing and 
> showing the user something useful.
> Above I am using a time and date with a  timezone which is 
> fixed for each recurring event. When creating the event, the 
> CEO decides in which timezone he thinks. If he makes the 
> event in Africa/Johannesburg that means this is 7:30 UTC in 
> January and July leading up to his client showing him 8:30 in 
> January and 9:30 in July when being in Europe/Berlin.
> > Another thing: Since none of the clients support actually 
> doing this, 
> > I think it's pretty theoretical.
> What does Kontact do currently, if we create such an event?
> Bernhard

So basically you would like to move the resposibility of translation from
stored date to local time away from the operating system to the mail client.


Joon Radley
Radley Network Technologies CC
Cell: +27 (0)83 368 8557
Fax: +27 (0)12 998 4346
E-mail: joon at radleys.co.za

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