4. Recommendations for the Future

The next DST transition in November 2007 is not expected to cause as many problems as was seen in March 2007, simply because the remediation already done covers all future transitions with these new rules. However, it is still possible that some calendaring events and systems were not correctly or completely updated, so administrators and users should again check all events due to occur between October 28th and November 4th 2007, and these checks should be done sooner rather than later to avoid the last minute rush to do fixes that we experienced in March 2007.

As was noted before, there is still some chance that the DST rules will be “rolled-back” to their previous definitions if the U.S. Congress determines there was positive effect on energy usage or conservation. Even if that does not happen, there is no guarantee that it will be another 20 years before the next U.S. changes are mandated, for whatever reasons. As many other countries, update their DST rules more frequently than the U.S., it’s clear that there needs to be a better way to manage changes to DST rules.

To that end, CalConnect’s TC-TIMEZONE is developing a recommendations document for a standard time zone registry that will provide a central, definitive repository of timezone and DST rules. This ad-hoc committee concurs that setting up such a timezone registry is important, and should be acted upon as soon as possible.

The benefits of such a registry are clear — vendors adopting this registry as a source for the timezone and DST rules can build updating procedures into their products so that future changes to rules are automatically handled by update processes similar to those already in place. This avoids the need for each vendor to distribute their own set of patches, and significantly lessens the support impact that system administrators have in applying those patches.

There are several hurdles that need to be overcome before such a registry could be viable, and TC-TIMEZONE’s work will attempt to address all of those. In addition, TC-TIMEZONE will define protocols for a timezone service that can be used as a means to carry out the automatic update process being proposed. This service would provide access to the timezone registry data as well as providing other useful features, such as a mechanism for quickly mapping between earlier timezone identifiers and the new standard form used in the registry. The service could provide a list of periods covering the date ranges where a timezone or DST rule change will impact existing data, providing a fast way to evaluate the changes needed to when an update needs to be applied.

For significant issues such as timezones, CalConnect should take a more proactive approach including using its public mailing list for system administrators, http://lists.calconnect.org/mailman/listinfo/caladmin-l, to provide regular updates on timezone changes and timezone processing. CalConnect might also consider providing a RSS feed of news related to calendaring and scheduling.