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Spring Forward, Fall Behind?

Every April, millions of Americans show up late for work, late for church and late for life. That's because Daylight Saving Time (DST) moves the clock forward at 2 a.m. Now, thanks to the U.S. Energy Policy Act of 2005, that dislocation is going to happen several weeks earlier than normal -- on March 11, to be exact.

Intended to help conserve energy by reducing nighttime use of lighting and other energy resources, the policy also impacts applications and software that employ date and time stamps or otherwise track, manipulate or act upon data based on the time of day.

At Microsoft, both Office 2007 and Windows Vista are tuned for the new schedule out of the box, but Windows XP requires an update (which went live yesterday) to get its clocks in order. Other affected products are getting tweaked via Microsoft Customer Service and Support, Windows Update, Microsoft Update, Windows Server Update Services (WSUS) and the Microsoft Download Center.

The new DST policy has also spurred Microsoft to make a change to the next version of Visual Studio, known as "Orcas," writes a Microsoft spokesperson: "In Visual Studio code name 'Orcas' we're fixing this by creating a new TimeZone2 class that supports multiple DST adjustments."

The change, of course, reaches beyond Microsoft packaged applications, and therein lies the challenge, the company writes: "While the Visual Studio IDE is not directly affected by this, applications built using Visual Studio and the .NET Framework may be. Additionally, other products may be sensitive to the date time changes."

Applications built using Microsoft's System.TimeZone class will conform to the underlying OS; however, time-sensitive custom apps with hard-coded DST values could end up an hour behind for four weeks. Previously, the DST switchover date was the first Sunday of April, or April 1 this year.

The "Preparing for Daylight Saving Time changes in 2007" page warns that: "In some cases, systems and applications may need to be updated directly, while in others, the application may simply inherit or "read" the date and time information from the underlying system that it resides on, so the changes need only be made to that underlying system. Given the broad range of technology in use today -- and the integration of systems between customers, vendors and partners -- business and IT managers should determine what actions should be taken to mitigate the effects of DST 2007 on their organizations."

In other words, check your code!

Posted by Michael Desmond on 02/14/2007 at 1:15 PM

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