Initial time zone setting

 

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During the initial startup, the i5/OS® operating system sets the initial time zone. This topic describes how the system determines the initial value for the time zone (QTIMZON) system value.

There is no shipped default value for the time zone (QTIMZON) system value. The time zone (QTIMZON) system value can be set in iSeries™ Navigator and from the IPL Options display during an attended initial program load (IPL).

To determine the initial value for the time zone (QTIMZON) system value, the operating system performs the following actions:

  1. Attempts to retrieve time zone from the QWCTIMZON data area

    During the IPL of an i5/OS software upgrade, the operating system will look for a data area named QWCTIMZON in the QSYS library. To create the data area before installation, see Setting the time zone before upgrading. If the data area is found, the following steps are taken:

    1. Attempts to find a time zone description object whose name matches the time zone description object named in the data area. If this step fails, proceed to 1.b.

    2. Attempts to find a time zone description object whose name is derived from the offset specified in the data area. This name consists of the letter Q, followed by an N if the offset is negative, or a P if the offset is positive; then it is followed by the offset hours and minutes; and finally by the letters UTCS. For example, if the offset specified in the data area is -06:00, the operating system attempts to find a time zone description named QN0600UTCS. Note that if the offset is zero, the character representing the sign (N or P) is omitted, and the name used is Q0000UTC. If this step fails, proceed to 1.c.

    3. Attempts to create a new time zone description whose name and offset match the information specified in the data area. This time zone description does not support DST. For example, if the data area specified is -05:15MYTIMEZONE, the operating system will attempt to create a time zone description named MYTIMEZONE with an offset of negative five hours and 15 minutes. If this step fails, proceed to 2.

  2. Attempts to retrieve time zone from the offset from UTC (QUTCOFFSET) system value

    If the data area QWCTIMZON does not exist, or the preceding steps fail, the operating system will attempt to use the value specified in the offset from UTC (QUTCOFFSET) system value. The following steps are performed:

    1. Attempts to find a time zone description object whose name is derived from the offset specified in the offset from UTC (QUTCOFFSET) system value. See 1.b for information about how this name is derived. If this step fails, proceed to 2.b.

    2. Attempts to create a new time zone description whose name was derived in the previous step 2.a and whose offset matches the information specified in the offset from UTC (QUTCOFFSET) system value. This time zone description will not support daylight saving time.

If all of the preceding steps fail, the time zone (QTIMZON) system value is not set. In iSeries Navigator, the time zone field is blank, and in the character-based interface, the time zone parameter is set to *N (not available). In addition, the offset from Coordinated Universal Time (UTC) is set to 0. Then, the system's local system time is set to the current UTC.

 

Parent topic:

Time zone
Related tasks
Setting the time zone before upgrading Setting the time zone during an attended IPL Offset from UTC was incorrectly set during i5/OS installation System time is incorrect and jobs are not running with the proper time
Related information
Date and time system values: Time zone Date and time system values: Offset from Coordinated Universal Time (UTC)