eWEEK Labs Sheds Light on Daylight-Saving Time 2007

What to do if you don't want to be left in the dark by the changes to DST this year.

Is it spring forward and fall back, or spring back and fall forward? As confusing as the beginning of daylight-saving time can be in general, it will be even more confusing this year to the IT managers who have to make sure that their companies computing systems arent left in the dark by a new schedule.

The United States will enter DST at 2 a.m. local time March 11—three weeks earlier than nearly all computer hardware and software written since 1986 are expecting. And DST 2007 will end one week later than this hardware and software expect—at 2 a.m. local time Nov. 4. These changes were mandated by the Energy Policy Act of 2005.

Its impossible to predict exactly what problems the DST changes will cause, but its likely that there will be a few missed meetings and issues with some time-sensitive transactions. For many users, the biggest problems will be that meetings scheduled through Microsofts Outlook and other calendaring programs may appear to start an hour earlier than actually planned. And some all-day events may appear to span two days if calendaring programs misinterpret the start and end time of a meeting.

/zimages/3/28571.gifClick here to read more about how IT pros are preparing to spring forward.

Overall, however, the negative effects of the DST change are likely to be on the same scale as Y2K: almost non-existent with the proper remediation. Based on research and discussions with hardware and software vendors, eWEEK Labs anticipates that DST 2007 will be most problematic for companies that use precise time stamping.

It doesnt help matters any that Microsoft and other vendors have delivered operating system patches so late in the game. (Some of these patches arrived only in mid-February.) That said, DST patches are now available for most major operating systems, and these patches should be applied as soon as possible. If practical, IT managers should include DST patches in the regular maintenance cycle used to install security and other patches to operating systems and applications. However, if you havent done any DST patching until now, focus on critical systems first.


After current operating systems have been patched, IT managers should work to patch embedded and legacy systems. For example, organizations with extended support agreements with Microsoft can get DST patches for Windows 2000 Server and Windows 2000 Workstation (for a $4,000 fee).

Patch management vendors can be a source of assistance for IT departments that are under the gun to make DST changes. For example, officials at PatchLink announced an offer to distribute DST remediation patches for all major operating systems, including legacy versions of Windows, Hewlett-Packards HP-UX, and Sun Microsystems Solaris. And BigFix officials have announced an offer to help with Windows patches.

Time Is on Our Side

It almost goes without saying that applications that explicitly use time stamps to schedule appointments and meetings should be reviewed carefully. For example, shops that use Microsoft Outlook 2000, 2002 and 2003 should download the Time Zone Data Update Tool for Microsoft Office Outlook here.

This tool works after the operating system is updated to adjust recurring and single-instance appointments scheduled in the period between the actual start of DST 2007 and when most applications are programmed for DST to start. The Time Zone Data Update Tool also adjusts for the end of DST 2007.

When you think about the systems that would be affected by a change to the way we perceive time and should thus be remediated, calendaring systems naturally come to mind first. But computers use time in almost every task.

For example, routers and other network infrastructure products time-stamp log entries and use schedules to enforce permit/deny access rules. In addition, a host of compliance reporting tools brought into existence by federal regulations use time-stamp logic and should be examined to see if they will accommodate the new dates for DST 2007.

/zimages/3/28571.gifRead more here about potential problems with the daylight-saving time change.

Most enterprise applications and systems use Coordinated Universal Time, which is abbreviated as UTC. To display local time information to a user, applications normally check the system clock on which the application is running. Applications that either dont use UTC or that hard-code the DST calculation will likely have problems until code remediation can be implemented.

Its a good idea to solicit employees to help with identifying time-sensitive applications, since some of these systems may be off the network. For example, shipping systems that must have the correct time to apply a valid postmark are likely not accessible on the corporate network.

The action of updating date and time usage is called rebasing. IT managers should prepare users now to rebase calendar systems used to track everything from billable hours to rental car returns and financial transactions.

Following are some more resources to help you manage the DST 2007 change:

  • The Sun Developer Network has a good collection of resources for Java developers here.
  • Microsoft provides a labor-intensive set of instructions for manipulating the registry in Windows 2000 Server to accommodate DST 2007 here; the official Microsoft help and support center is here.
  • IT managers can buy a license for the Unofficial Windows 2000 DST time patch from IntelliNavigators IntelliAdmin here.

eWEEK Labs Technical Director Cameron Sturdevant can be reached at cameron_sturdevant@ziffdavis.com.

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