Daylight Saving Time (DST) Information on IBM System i servers

Abstract

The Energy Policy Act of 2005 was passed by the United States Congress on July 29, 2005 and signed into law on August 8, 2005. This law changes the time-change dates for Daylight Saving Time in the United States. Beginning in 2007, DST will begin on the second Sunday in March and end on the first Sunday in November. In addition to the U.S., Canada and Bermuda have decided to change their DST dates in 2007 to follow the same time zone rules. For general IBM information on this update, refer to the Daylight Saving Time alert page.

This Technote explains how this change is being implemented on IBM System i servers.

Written by Pat Glenski
IBM i5/OS Globalization Architect
IBM Rochester

Contents


i5/OS Updates
i5/OS has built-in support for time zones. The time zone system value (QTIMZON) specifies the name of the time zone description that is used to calculate local system time. To reflect this DST change in i5/OS, the system simply needs to be told what the new rules are. IBM is providing PTFs to update the rules.

The updates for DST for i5/OS are available as:
  • V5R4M0, SI26040, and SI25990
  • V5R3M0, SI26039, and SI25991

These PTFs will automate the changes needed to support the new DST information for the following time zone objects that observe DST. Listed are the existing time zones objects and the new replacement objects in base i5/OS (for more information, see the PTF cover letter).

Workaround
If you do not have the opportunity to install these PTFs, you can effectively get the same behavior of the changed DST rules by manually changing your system. See the Daylight Saving Time Manual Instructions section on this page for more information.



Time zone descriptionNew 2007 rules
QTIMZON value
Prior  QTIMZON value
Atlantic TimeQN0400AST2QN0400AST
Eastern TimeQN0500EST3QN0500EST
Central TimeQN0600CST2QN0600CST
Mountain TimeQN0700MST3QN0700MST
Pacific TimeQN0800PST2QN0800PST
Alaska TimeQN0900AST2QN0900AST
Hawaii-Aleutian TimeQN1000HAS2QN1000HAST


Note: If you are a customer whose system is in the US, Canada, or Bermuda and you are using another TIMZON value to represent one of the time zones that observe DST in the table above, you should use the new 2007 value for your location from the list above.

i5/OS Versions prior to V5R3M0
No update is needed for earlier releases because automatic DST support was added in V5R3M0.


Other updates related to i5/OS
Here are other updates related to i5/OS

Java
Java on i5/OS was updated to support this DST change with the following updates:



 V5R2V5R3V5R4Supports new
DST rules for
 
JDK 1.2.2SI26480
 
5722JV1 Opt 3
(Not supported)(Not supported)United States
Canada
Bermuda
Western Australia
Yes
Yes
Yes
Yes
JDK 1.3.1SI25967
 
5722SS1 Opt 3
(default JDK)
SI25968
 
5722JV1 Opt 5
SI25969
 
5722JV1 Opt 5
United States
Canada
Bermuda
Western Australia
Yes
Yes
Yes
Yes
JDK 1.4SI25966
 
5722JV1 Opt 6
SI26838
 
5722SS1 Opt 3
(default JDK)
SI26839
 
5722SS1 Opt 3
(default JDK)
United States
Canada
Bermuda
Western Australia
Yes
Yes
Yes
Yes
JDK 5.0
64 bit
(Not supported)SI26837
 
5722JV1 Opt 7
SI26840
 
5722JV1 Opt 7
United States
Canada
Bermuda
Western Australia
Yes
Yes
Yes
Yes
JDK 5.0
32 bit
(Not supported)(Not supported)SI24622
 
5722JV1 Opt 8
SR3
United States
Canada
Bermuda
Western Australia
Yes
Yes
No *
No *
* Available with SR4. Projected to be available in early March 2007, or you can use the tzupatch tool for i5/OS. For more information on the tzupatch tool, refer to the tzupatch page.
For more information about Java’s DST support, refer to the i5/OS Java Software Technical Document.


International Components for Unicode (ICU) 5722SS1 Option 39
ICU on i5/OS was updated to support this DST change. If you have this option installed, you should load the following updates:
  • V5R4M0 SI25400
  • V5R3M0 SI25399

Hardware Management Console (HMC)
The HMC was updated to support this change. Refer to the HMC Daylight Savings Time Page for more information.

Other information related to i5/OS

Flexible Service Processor (FSP): The FSP is not impacted by this change.

Portable Application Solutions Environment (PASE)
PASE is not impacted by this change (covered by i5/OS support) unless you are explicitly specifying the i5/OS PASE time zone using the TZ or PASE_TZ environment variable. Refer to the PASE Daylight Savings Time Page for more information.

iSeries Navigator
iSeries Navigator is not directly impacted by this change (covered by i5/OS support). However, iSeries Navigator is among the IBM software that includes a Java Runtime Environment (JRE) that is provided by the IBM Center for Java Technology Development. Third-party plug-ins to iSeries Navigator may use the JRE shipped with iSeries Navigator, and you may see DST issues when using them, depending on the Java features they use. If you discover issues, the IBM Center for Java Technology Development has produced a tool to update the Daylight Saving Time (DST) information in the JRE. For instructions on how to update this included JRE, refer to Informational APAR II14264 for more information.

More information can be found at:
http://www-912.ibm.com/s_dir/slkbase.NSF/1ac66549a21402188625680b0002037e/e6b70947c041f96d86257290007c5200?OpenDocument

http://www.ibm.com/support/alerts/us/DST_FAQ_11-14-06.pdf

Special Notices

This material has not been submitted to any formal IBM test and is published AS IS. It has not been the subject of rigorous review. IBM assumes no responsibility for its accuracy or completeness. The use of this information or the implementation of any of these techniques is a client responsibility and depends upon the client's ability to evaluate and integrate them into the client's operational environment.

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Publish Date
07 March 2007


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