Time schedule requests

A time schedule request is a statement in a TCO script that tells IMS to process a particular task at a specified time. A time schedule request also specifies which exit routine is scheduled and what data should be passed to the exit routine.

A time schedule request can specify:

A time schedule request either contains 16 bytes of data or refers to a variable-length message set that contains one or more single segment or multi-segment messages.

 The following figure shows two message sets and time schedule requests for broadcasting a message. The example also shows a scale to indicate the alignment of the fields.

 .........1.........2.........3.........4.........5.........6.........7.........8
 
 /BRO LTERM CTRL                                                        S00000001
 THE IMS TIME-CONTROLLED OPERATION IS UP.                                00000002
 *TIME      DFSTXIT0            S                       ****             00000003
 /BRO LTERM CTRL                                                        S00000004
 FIVE MINUTES HAVE ELAPSED SINCE STARTUP, AND TCO IS ACTIVE.             00000005
 *TIME      DFSTXIT0      0005  S                       ****             00000006
In this example, the first message set is: 
/BRO LTERM CTRL
THE IMS TIME-CONTROLLED OPERATION IS UP
The presence of the S in column 72 indicates the end of a segment and that the next segment is part of the same message. If there are any errors in this message set, the numbers will be added to the error message. The time schedule request indicates that this broadcast should take place as soon as the script is initialized.
The second message set in this example is: 
/BRO LTERM CTRL
FIVE MINUTES HAVE ELAPSED SINCE STARTUP, AND TCO IS ACTIVE
The associated time schedule request indicates that this message should be broadcast 5 minutes after the script is initialized.

Required fields for time schedule requests

The required fields for a time schedule request specify the following: the time you want the task to be performed, and to which exit routine to pass the script.

  • Columns 1-5 (ID) IDENTIFICATION

    Must contain the characters *TIME. All other requests are treated as message sets.

  • Columns 12-19 (NAME) USER EXIT ROUTINE NAME

    Must include the one- to eight-character name of the exit routine in the IMS.SDFSRESL data set. If the name has fewer than eight characters, it must be left-justified and padded to the right with blanks. NAME must begin in column 12.

Optional fields for time schedule requests

By specifying one or more optional fields, you can request tasks to be processed during IMS startup or at a specified time following startup. You can also specify for processing to start, stop for an interval, and then restart.

  • Columns 7-10 (HHMM) START TIME

    The time the task should start. A start time is required unless the request is for startup. Valid values for HH are 00 to 23, and valid values for MM are 00 to 59.

  • Columns 21-24 (HHMM) END TIME

    The time the task should end. Use this field only if you specify an interval time in columns 26-29. Otherwise, the field is ignored. This time must be a later time than the start time specified in columns 7-10. Valid values for HH are 00 to 23, and valid values for MM are 00 to 59.

    If you request multiple dispatching for a task, the end time also stops the multiple dispatching. If you do not specify an end time, multiple dispatching continues until the end of the day (2359).

  • Columns 26-29 (HHMM) INTERVAL TIME

    This field specifies the amount of time you want to defer a request. The interval time can be any time after the start time (or startup) to a time before this request is to be dispatched. Valid values for HH are 00 to 23, and valid values for MM are 00 to 59.

  • Column 31 (Flag) RESIDENT INDICATOR
    Specifies whether the exit routine is resident in memory. If you specify any request for an exit routine as resident, all requests use the resident copy. The options for this column are:
    Blank
    The exit routine is resident and paged in and out as required.
    D
    The exit routine is loaded each time a request is generated.

    There is an advantage and a disadvantage to specifying the exit routine as resident:

    • Advantage: the request is performed more quickly because the system does not have to load the routine each time it is needed to process a time schedule request.
    • Disadvantage: the resident copy is always used; IMS does not load a new copy. If you want to load a new copy of the exit routine, you must either change the resident indicator on the time schedule request statements to D, or reload the TCO script using DFSTCF LOAD.
  • Column 32 (Flag) DISPATCH INDICATOR
    Specifies when the request is dispatched (started). The options for this column are:
    Blank
    The request is dispatched each day at the start time specified in columns 7-10. The start time in columns 7-10 is required.
    O
    The request is dispatched the first day the script member is loaded. It is not dispatched again until the TCO script is reinitialized. A start time in columns 7-10 is required.
    S
    The request is dispatched as soon as the script member is initialized, either when IMS starts or when the script member is loaded. The start time, if specified in columns 7-10, is ignored.

    If you specify an interval time in columns 26-29, the request is delayed from startup before the request is scheduled. With the S option, the request is processed only once each time IMS is initialized or the script-member is reloaded.

  • Columns 33-35

    Reserved

  • Columns 56-71 MESSAGE FLAG

    This field includes 16 bytes of data to be passed to the exit routine, plus the time of day. You can choose any data, or you can leave the field blank. If you set this flag to ****, the previous message set, if any, is passed to the exit routine instead of the 16 bytes found in the time schedule request.

  • Columns 73-80 LINE NUMBER

    Sequence numbers for the requests. If IMS or the TCO Verification utility detects an error, the number found in columns 73-80 is included in the error message to help you to identify the cause of the error.

    Recommendation: Include sequence numbers for all commands and message sets.