URGENT Actions Required: Changes to Daylight Saving Time will affect Tivoli Storage Optimizer for z/OS

Flash (Alert)


Information about the impact of the US Energy Policy Act of 2005, which changes the effective dates of US Daylight Saving Time (DST) in 2007. Actions are required to address this issue in Tivoli Storage Optimizer for z/OS.


A provision of the United States Energy Policy Act of 2005 extends DST by four weeks, beginning in 2007. Several countries (Canada, Bermuda) are also implementing the same DST change; other countries may decide to make similar changes to DST rules.

Beginning in 2007, DST start and end dates will be:

  • Start date: Second Sunday of March (11 March 2007)
  • End date: First Sunday of November (4 November 2007)

Systems or applications that process dates and times could be affected by this change. If not addressed, time and date calculations could be incorrect.

How do I know if my systems could be affected?
Your systems are likely to be affected by this change, even if you are operating outside of the US. Date and time processing functions in systems and applications in countries implementing the new DST rules (U.S., Canada, Bermuda) are affected. Systems and applications in countries not implementing the DST changes could be impacted if they support users, transactions or applications originating in countries which are implementing the new DST rules. For example, scheduling or synchronizing problems may arise where systems make or check date or time stamps relating to transactions in other countries, or there may be difficulty in scheduling meetings.

What could happen if I do not update my systems?
Systems or applications that rely on date or time processing functions could make incorrect calculations. Calendar, scheduling, or synchronizing problems could arise where systems use date or time stamps, or if dates or times are processed or manipulated in any way. In short, if your system makes date or time calculations, you may experience calculation errors. There is no workaround for this problem. A fix must be installed.

What do I need to do to protect my systems?
Some systems and applications can be fixed now. Other systems and applications recognize only one DST rule at a time and should not be patched until after the first Sunday in November, 2006, when the US has returned to Standard Time.

DST fixes for Tivoli Storage Optimizer for z/OS
Customers running Tivoli Storage Optimizer for z/OS will need to install two updates:
  1. A fix is required to the Tivoli Storage Optimizer product. This fix became available on January 30, 2007 and can be downloaded from: http://www-1.ibm.com/support/docview.wss?rs=1055&context=SSX3FM&dc=D400&uid=swg24014739&loc=en_US&cs=UTF-8&lang=en
  2. In addition, customers will need to upgrade the z/OS Java application using the IBM Time Zone Update Utility for Java (JTZU):

JTZU Flash:

JTZU Tool:

Additional information regarding IBM Java and DST changes:
Where can I get more information?
Consolidated information on the impact of DST changes on IBM products is be available at http://www.ibm.com/support/alerts/daylightsavingstimealert.html

For more information on the provision, see the Energy Policy Act of 2005

Change History
10 Nov 2006 Flash Created
10 Jan 2007 Flash updated with JTZU information

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Tivoli Storage Optimizer for z/OS

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