Lisa A. Johnson
 
 

Daylight Saving Time 2OO7

Enterprise applications could fall behind or fail if they're not adjusted in time.
Daylight-saving time is about to leap forward to March 11 instead of what would have been the normal April 1 change, and there's a chance your in-house enterprise applications won't keep up.

Instead of moving their clocks an hour ahead on March 11, enterprise apps may fall behind or even fail. For applications and systems that work within one international time zone, this means they need to be reset to move forward an hour on the correct day and time. But for systems and apps that work across international time zones, the fix is more complicated, and they "may face considerable confusion."

Such systems are set to have one day a year that's 25 hours long and another that's 23 hours. They typically work off Coordinated Universal Time, an international timekeeping system, similar to Greenwich Mean Time. These enterprise systems are set to make the switchover to daylight-saving time on April 1. So from March 11, when the United States makes its earlier-than-usual change, until April 1, those systems and apps will be working off incorrect times.

Many enterprise applications are custom systems developed in-house. For example, scheduling and manufacturing systems with real-time components require precise time calculations, as do applications that calculate tariff charges or service billing based on elapsed time totals. These systems "are most likely to be affected."

Applications associated with transportation, health care, financial services, telecommunications, and manufacturing, particularly process manufacturing where chemical mixtures are pressurized or heated, rely on correct timing information to perform their tasks and can't afford to be off by even an hour. Also, server log files from which electronic events, such as financial transactions, might be reconstructed are in jeopardy of being off by an hour. For example, a system that's off by an hour would significantly affect the value of trades that a currency or commodity trader makes.

Do it right --Developers of custom applications should know how their time functions work because the original process of building them wasn't simple. But often the original developers are long gone, and someone less familiar with the source code has to decipher how the program's date and time functions operate.

The amount of work involved depends on whether the date and time functions are programming-language specific. C++, Visual Basic, and C# rely on the operating system's time zone tables. Object-oriented programming languages such as Java and Smalltalk depend on virtual machine-related language frameworks for time calculation.

Testing is the other key to a successful transition. Regression tests should be executed against the patched and updated systems to ensure that they're running as expected, "especially in the case of poorly documented systems with old code."

Agresso, Epicor Software, IBM, Infor Global Solutions, Lawson, Microsoft, Oracle, Sage, SAP, and Sterling Commerce --that rely on the operating system for time information, so applying a patch to the system's time zone change section fixes the problem. Applications that depend on Oracle Application Server and Oracle databases can't rely on just an operating system change and may need patches or updates to the application server and database. And users of pre-2OO7 Microsoft Outlook and Microsoft Exchange must apply manual downloads.

 
Software Notes More information

Desktops:

Linux — Novell SUSE

Service packs or updates available for multiple products/versions.

Linux — Red Hat

Red Hat Desktop v.3 and v.4 require a tzdata update. The update referred to in Advisory RHEA-2006:0622-3 contains necessary updates even though the U.S. rule changes effective in 2007 are not mentioned directly (the update is cumulative).

Mac OS X

Apple is providing software updates for Mac OS X 10.3 and 10.4 based on worldwide time zone information available as of January 8, 2007. To make sure that your clock maintains the proper time, simply install the updates that are shown for your computer in Software Update. You should install these updates even if your computer is used in a time zone that is not affected.

Windows

Update available for Windows XP SP2; for Windows 2000, an update is available under Extended Hotfix Support. No update needed for Vista. For earlier (unsupported) Windows desktop OS's, manual update methods are described in MS Knowledge Base article 914387: How to configure daylight saving time for the United States in 2007.

Servers:

AIX

There are specific point patches for AIX that address the DST issue. Those customers wishing to minimize the impact to their systems can install the APAR specific to their version. See below for updates required to Java JREs running on AIX.

Linux — Novell SUSE

Service packs or updates available for multiple products/versions.

Linux — Red Hat

Red Hat Enterprise Linux 2.1 users must update glibc. Red Hat Enterprise Linux 3 and 4 must update the tzdata package.

Solaris

Issues can occur in versions 2.5.3, 2.6, 7, 8, 9, and 10.

WebSphere

Patch required.

Windows Server 2003, Windows Server SP1, Exchange Server

Updates available for versions in Mainstream Support. Exchange Server 2007 requires no update.

Databases:

MS SQL Server

Patches must be applied for SQL Server Notification Services.

MySQL

Load MySQL time zone tables from a patched operating system that contains a zoneinfo database, or from files downloaded from MySQL.com (if running MySQL on Windows or HP-UX).

Oracle

Affects Oracle Server — Enterprise Edition — Versions 8.1 to 10.2. A database patch and a JVM (Java Virtual Machine) may need to be applied. Documentation at the provided URL links to more detailed documents available to Oracle licensees with MetaLink access.

PostgreSQL

Pre-8.0 PostgreSQL versions use the OS timezone database. PostgreSQL releases (v. 7.3 through 8.2) made available after January 8, 2007, have updated timezone databases.

Sybase

Sybase Servers recognize date and time portions values provided by the operating system. Applications running on older Java Runtime Environments JREs require patching.

Languages / application platforms:

Cold Fusion

ColdFusion MX 6.1 Updater 1 and ColdFusion MX 7.0.2 have been certified for JVM 1.4.2_11, which incorporates the new Daylight Savings time rules. MX 6.1 users will need to review Tech Note KB article 400232: ColdFusion MX 6.1 Updater 1: Hot fix for NullPointer Exceptions after upgrading to 1.4.2_06 JDK/JRE or higher.

Java (Sun)

The Java Runtime Environment (JRE) stores rules about DST observance. Older JREs contain outdated rules; applications running on an older JRE may report incorrect time from March 11 through April 2, and October 29 through November 4, 2007. The following versions contain rules that comply with the new U.S. DST dates:

  • Java SE 6 or later
  • J2SE 5.0 Update 6 or later
  • J2SE 1.4.2_11 or later
  • J2SE 1.3.1_18 or later

In addition, for version 1.4 or later, you can alternately use the tzupdatertool to modify time zone data within an existing JRE.

Note that Sun's instructions (linked at right) are for Sun JREs (which generally run on Solaris, Linux, and Windows operating systems). See below for links related to IBM- or Apple-flavored JREs.

Java (IBM)

The IBM Time Zone Update Utility for Java (JTZU) updates the time zone information in IBM supplied releases and service refreshes of the Java SDK and JRE.

Java (Apple)

For Mac OS X 10.4 and Mac OS X Server 10.4, install Java for Mac OS X 10.4, Release 5. For Mac OS X 10.3 and Mac OS X Server 10.3, install Java for Mac OS X 10.3, Update 5.

Python

pytz (world timezone definitions for Python) is compiled into Python. This may or may not result in exposure to problems due to DST changes, depending on whether and how pytz classes are utilized in an application.

Mobile devices:

BlackBerry

BlackBerry smartphones will not update their clocks for affected time zones if software patches are not applied.

Palm

Palm devices, both smartphones and handhelds, need to be updated so that they reflect the correct time when the new DST changes take effect. Without the Daylight Saving Time Updates, calendar events and email messages will indicate an hour off the actual time in locations that observe DST.

Windows Mobile (2003 and 5.0)

Microsoft is providing an update tool for Windows Mobile devices. You will also need to update Microsoft Windows (see above) and Microsoft Outlook on each PC where you synchronize your mobile devices.
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