2007 Daylight Saving Time Technical Summary for the Operating System

Background

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, Daylight Saving Time will begin on the second Sunday in March and end on the first Sunday in November. In addition to the United States, Canada and Bermuda have decided to change their Daylight Saving Time dates in 2007 to follow the same time zone rules.

For more information on all of IBM’s Daylight Saving Time changes, refer to the Daylight Saving Time alert Web site:

http://www.redbooks.ibm.com/abstracts/tips0655.html



History of Operating System Updates

IBM produced three updates for this time change. In March and November 2006, Daylight Saving Time support was updated with the following set of PTFs:

V5R2 SI23325
V5R3 SI25991, SI23318, SI23330, SI26039
V5R4 SI25990, SI23335, SI23334, SI26040

In December 2006, Daylight Saving Time support was updated for Western Australia with the following set of PTFs:

V5R2 SI25966
V5R3 SI25991, SI25960, SI25958, SI26039
V5R4 SI25990, SI25965, SI25959, SI26040

In February 2007, Daylight Saving Time support for Java™ was updated with the following set of PTFs to correct issues in the December 2006 update:

V5R2 SI25966
V5R3 SI26753, SI26838, SI26837, SI26039
V5R4 SI26773, SI26839, SI26840, SI26040

Special Note: If your system has the December set of PTFs applied however the February set of PTFs is not applied, your system must be updated to get the correct Daylight Saving Time action in Java.

Only users of JDK 1.4 and 5.0 are affected. If you are impacted, you should take action A, B, or C before March 11. Otherwise, your system will not support the time zone change correctly in Java.

Actions

A	Remove the December set of PTFs to go back to the March set of PTFs which will allow your system to support the North America time zone change correctly. However, it will not support the Western Australia change. If you need Western Australia support and North America support, the February set of PTFs must be applied or choose Option C.
B	Install the February set of PTFs which will allow your system to support the time zone change correctly. Note: The system may not support the time zone updates correctly if it has the Java applications that explicitly set the user.timezone property value. Refer to the Note on Eastern Standard Time (EST) for more details.
C	If you cannot change the PTFs that are loaded on your system at this time, use the instructions listed below in the section i5/OS Daylight Saving Time Manual Instructions.

Regardless of which action you select, IBM recommends that all users apply the February set of PTFs at the next scheduled maintenance window to ensure that the system’s Java time zone support is the most current.

Note: If you are impacted by the problem discussed in the section Note on Eastern Standard Time (EST) before you apply the February PTF set, be aware that these PTFs might require all active Java virtual machines to be ended.

If you have not already done so, it is recommended you read the information posted on the Operating System Daylight Saving Time Web site.


Getting the Updates

You can use your service provider, the SNDPTFORD command, or Fix Central to get the necessary PTFs.

Click on the following link for Fix Central:

http://www.ibm.com/eserver/support/fixes/fixcentral/main/iseries/

Notes on Eastern Standard Time (EST) and Mountain Standard Time (MST)

Users with EST or MST Explicitly Set for the Java user.timezone Property Value

The February set of PTFs does not support the Daylight Saving Time rule change correctly if your system has the Java property user.timezone explicitly set to be EST (Eastern Standard Time) or MST (Mountain Standard Time).

The most common way this is set is in the /QIBM/UserData/Java400/SystemDefault.properties file. If you see an entry similar to user.timezone=EST, action is required.

In addition, IBM® WebSphere® Application Server users might have set the user.timezone Java system property when configuring their application server. In this case, the setting is found in the server.xml file for the application server.

The December set of PTFs introduced a difference for the EST and MST 3-character time zone identifiers defined by Java. Prior to this update, these values observed Daylight Saving Time. After these December updates, they do not observe Daylight Saving Time.

If you explicitly set user.timezone to EST (Eastern Standard Time) or MST (Mountain Standard Time), do one of the following actions:

o	If you are running V5R3 or later and have the QTIMZON system value set to QN0500EST3 or QN0700MST3, remove the user.timezone property and allow the system to use the default.
o	Update your configurations to use the Java long name form as soon as possible or your time information in Java will be incorrect by one hour.

To edit the system-wide Java properties file, run the following command:

EDTF STMF('/QIBM/UserData/Java400/SystemDefault.properties')

An example of an updated entry for Eastern Standard Time (observing Daylight Saving Time) follows:

user.timezone=America/New_York

An example of an updated entry for Mountain Standard Time (observing Daylight Saving Time) follows:

user.timezone=America/Denver

Important Note: You might also need to update the configurations for specific Java applications to use the Java long name form for the user.timezone property.

Java has moved away from the use of 3-letter time zone abbreviations. To avoid future issues caused by explicitly setting user.timezone to a 3-letter time zone abbreviation, you should remove the user.timezone property or you should update your setting of user.timezone to use the Java long name form.

Common Questions Relating to This Daylight Saving Time Update

Question 1: What if I run multiple WebSphere Application Server instances and have already set each of them to a different time zone?

Answer 1: Determine if any of them have the time zone value set to EST or MST. If so, change them to the new values listed. To change them, use the WebSphere Application Server administrative console to modify the Java Virtual Machine settings for the server in question.

Refer to the following Web site for additional information on WebSphere Application Server and its Daylight Saving Time support:

http://www.ibm.com/support/knowledgecenter/SSAW57_8.5.5/com.ibm.websphere.nd.doc/ae/trun_svr_timezones.html

Question 2: If the user follows the manual instruction to create the time zone objects, modifies the Java properties file, and puts the PTFs on later, are there any problems or actions they should do?

Answer 2: There should not be any problems. It is recommended that, after you have applied the latest PTFs, you remove the entry in the Java properties file so the system will go back to using the defaults (in the event that there are future Java changes).

Operating System Daylight Saving Time Manual Instructions

IBM recommends that all users apply the revised February set of PTFs. The instructions provided below are an alternative to the PTFs.

Note: All instructions and PTFs are provided as is, without warranty of any kind, express or implied.

Step 1: Decide what time zone you want the operating system to run in:

Atlantic Time
Eastern Time
Central Time
Mountain Time
Pacific Time
Alaska Time
Hawaii-Aleutian Time

Step 2: For each of these locations do the following:

1.

Create the QTIMZON object required (this is only for systems running V5R3 and V5R4). These changes will take effect right away. If you have applied any of the Daylight Saving Time updates, these TIMZON objects might already exist on your system. If so, there is no need to create them.

2.

Modify the Java settings for the system to indicate the time zone required. Important Notes: a. If you do not have at least the March/November set of PTFs installed (see General Information), the latest set for your release must be installed. Without some version of Java DST PTFs installed, Java will not observe the 2007 DST rules. b. If you have the March/November or later set of PTFs applied, change the Java properties file to set the new time values. Before the Java change will take effect, any Java virtual machine that is running must be restarted.

Sign on with a user profile that has QSECOFR authority. Refer to the following sections for the commands to use for your specific time zone.
Mountain Time For the Mountain time zone, do the following:

1.

Issue the following CL commands for the i5/OS time zone actions: QSYS/CRTTIMZON TIMZON(QN0700MST3) OFFSET(-420) STDNAME(*MSG) DSTNAME(*MSG) STDMSG(CPX0926) DSTMSG(CPX0927) MSGF(QCPFMSG) DSTSTR(*MAR *SUN 2 0200) DSTEND(*NOV *SUN 1 0200) TEXT('CREATED BY CUSTOMER') AUT(*USE) If you receive the error message CPF2112 - TIMZON already exists after running the previous command, run the following command: QSYS/CHGTIMZON TIMZON(QN0700MST3) OFFSET(-420) STDNAME(*MSG) DSTNAME(*MSG) STDMSG(CPX0926) DSTMSG(CPX0927) MSGF(QCPFMSG) DSTSTR(*MAR *SUN 2 0200) DSTEND(*NOV *SUN 1 0200) TEXT('CHANGED BY CUSTOMER') Then, run the following commands: QSYS/CHGOBJOWN OBJ(QSYS/QN0700MST3) OBJTYPE(*TIMZON) NEWOWN(QSYS) CUROWNAUT(*REVOKE) QSYS/CHGSYSVAL SYSVAL(QTIMZON) VALUE(QN0700MST3)

2.

To change the Java properties file, run the following CL command: QSYS/EDTF STMF('/QIBM/UserData/Java400/SystemDefault.properties') Add the following line to that file. Ensure it is the only user.timezone line in that file. This file is case-sensitive and must be typed exactly as shown: user.timezone=America/Denver Save the file and exit the editor.

Pacific Time For the Pacific time zone, do the following:

1.

Issue the following CL commands for the i5/OS time zone actions: QSYS/CRTTIMZON TIMZON(QN0800PST2) OFFSET(-480) STDNAME(*MSG) DSTNAME(*MSG) STDMSG(CPX092A) DSTMSG(CPX092B) MSGF(QCPFMSG) DSTSTR(*MAR *SUN 2 0200) DSTEND(*NOV *SUN 1 0200) TEXT('CREATED BY CUSTOMER') AUT(*USE) If you receive the error message CPF2112 - TIMZON already exists after running the previous command, run the following command: QSYS/CHGTIMZON TIMZON(QN0800PST2) OFFSET(-480) STDNAME(*MSG) DSTNAME(*MSG) STDMSG(CPX092A) DSTMSG(CPX092B) MSGF(QCPFMSG) DSTSTR(*MAR *SUN 2 0200) DSTEND(*NOV *SUN 1 0200) TEXT('CHANGED BY CUSTOMER') Then, run the following commands: QSYS/CHGOBJOWN OBJ(QSYS/QN0800PST2) OBJTYPE(*TIMZON) NEWOWN(QSYS) CUROWNAUT(*REVOKE) QSYS/CHGSYSVAL SYSVAL(QTIMZON) VALUE(QN0800PST2)

2.

To change the Java properties file, run the following CL command: QSYS/EDTF STMF('/QIBM/UserData/Java400/SystemDefault.properties') Add the following line to that file. Ensure it is the only user.timezone line in that file. This file is case-sensitive and must be typed exactly as shown: user.timezone=America/Los_Angeles Save the file and exit the editor.

Alaska Time For the Alaska time zone, do the following:

1.

Issue the following CL commands for the i5/OS time zone actions: QSYS/CRTTIMZON TIMZON(QN0900AST2) OFFSET(-540) STDNAME(*MSG) DSTNAME(*MSG) STDMSG(CPX092E) DSTMSG(CPX092F) MSGF(QCPFMSG) DSTSTR(*MAR *SUN 2 0200) DSTEND(*NOV *SUN 1 0200) TEXT('CREATED BY CUSTOMER') AUT(*USE) If you receive the error message CPF2112 - TIMZON already exists after running the previous command, run the following command: QSYS/CHGTIMZON TIMZON(QN0900AST2) OFFSET(-540) STDNAME(*MSG) DSTNAME(*MSG) STDMSG(CPX092E) DSTMSG(CPX092F) MSGF(QCPFMSG) DSTSTR(*MAR *SUN 2 0200) DSTEND(*NOV *SUN 1 0200) TEXT('CHANGED BY CUSTOMER') Then, run the following commands: QSYS/CHGOBJOWN OBJ(QSYS/QN0900AST2) OBJTYPE(*TIMZON) NEWOWN(QSYS) CUROWNAUT(*REVOKE) QSYS/CHGSYSVAL SYSVAL(QTIMZON) VALUE(QN0900AST2)

2.

To change the Java properties file, run the following CL command: QSYS/EDTF STMF('/QIBM/UserData/Java400/SystemDefault.properties') Add the following line to that file. Ensure it is the only user.timezone line in that file. This file is case-sensitive and must be typed exactly as shown: user.timezone=America/Anchorage Save the file and exit the editor.

Hawaii-Aleutian Time For the Hawaii-Aleutian time zone, do the following:

1.

Run the following CL commands for the operating system time zone actions: QSYS/CRTTIMZON TIMZON(QN1000HAS2) OFFSET(-600) STDNAME(*MSG) DSTNAME(*MSG) STDMSG(CPX0931) DSTMSG(CPX0932) MSGF(QCPFMSG) DSTSTR(*MAR *SUN 2 0200) DSTEND(*NOV *SUN 1 0200) TEXT('CREATED BY CUSTOMER') AUT(*USE) If you receive the error message CPF2112 - TIMZON already exists after running the previous command, run the following command: QSYS/CHGTIMZON TIMZON(QN1000HAS2) OFFSET(-600) STDNAME(*MSG) DSTNAME(*MSG) STDMSG(CPX0931) DSTMSG(CPX0932) MSGF(QCPFMSG) DSTSTR(*MAR *SUN 2 0200) DSTEND(*NOV *SUN 1 0200) TEXT('CHANGED BY CUSTOMER') Then, run the following commands: QSYS/CHGOBJOWN OBJ(QSYS/QN1000HAS2) OBJTYPE(*TIMZON) NEWOWN(QSYS) CUROWNAUT(*REVOKE) QSYS/CHGSYSVAL SYSVAL(QTIMZON) VALUE(QN1000HAS2)

2.

Change the Java properties file. Issue the following CL command: QSYS/EDTF STMF('/QIBM/UserData/Java400/SystemDefault.properties') Add the following line to that file. Ensure it is the only user.timezone line in that file. This file is case-sensitive and must be typed exactly as shown: user.timezone=America/Adak Save the file and exit the editor.