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Re: "RDF Calendar - an application of the Resource Description Framework to iCalendar Data"

From: Graham Klyne <GK@ninebynine.org>
Date: Mon, 19 Sep 2005 14:27:41 +0100
Message-ID: <432EBCCD.50306@ninebynine.org>
To: Dan Connolly <connolly@w3.org>
CC: www-rdf-calendar@w3.org

Dan Connolly wrote:
> Hi from Chicago airport (ORD).
> I found some time to work on the report I started a while ago...
> http://www.w3.org/2002/12/cal/report1173.html

One approach, exemplified by the datetime design pattern in the
microformats community, is to not use iCalendar timezones, but only UTC

I recall a recent posting in ACM RISKS forum:
Date: Thu, 28 Jul 2005 14:08:04 +1000
From: Stuart Prescott <stuart@nanonanonano.net>
Subject: Re: Proposed daylight saving time changes (RISKS-23.94)

For the Olympics in 2000, the state government (New South Wales) decided to
start daylight saving almost 2 months early (in August) so that the Olympics
visitors would benefit from the longer evenings. Some of the other states in
Australia followed suit.

In the organisation I was then working for, the problem was that it took
quite some time for a patch to come from Microsoft to update the Windows NT
and 2000 operating systems that were being used.

The RISK was not that we had to revert to the good old days of manually
changing the time on the computer with the widely used calendar applications
like Microsoft Outlook. It turned out that MS Outlook stores all appointment
times in UTC, converting between local time and UTC when the appointment is
made and then back again when displaying the appointment. Installing the
updated TZ info from MS changed this conversion but not the stored UTC data.

So what ended up happening was that every appointment that was scheduled in
the period between between August and October that was entered into the
diary before the TZ update was applied was wrong by one hour after the TZ
patch was applied. Similarly, if you sent an appointment to someone who
didn't have the TZ patch installed (but had manually changed their time for
those two months), then the times would also be out for that appointment.

For those who were heavily reliant on their MS Lookout calendar, it made
for an interesting couple of months...
-- http://catless.ncl.ac.uk/Risks/23.95.html#subj18


Nearby, s/policitcal/political/


BTW, I enjoyed reading the piece;  several themes were nicely drawn
together, I think.

Graham Klyne
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Received on Monday, 19 September 2005 13:42:09 UTC

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