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CA Datacom Core - 15.1
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INIT Data Area (Format Data Area)

Last update March 15, 2019

The INIT Data Area option formats one (or all) data area(s) in a database. It updates the first block with control information. This first block is subsequently updated when maintenance is performed. The block size used is the size specified for the area in the Directory (CXX) definition.

Performing an INIT on a data area has no performance benefit. It should only be done before the first load, and then only if needed. An INIT of an Index or data area clears the utility history for that area (see Type H - Utility Function History Report).

Note: When you specify VERIFY=YES, information in the control block is preserved instead of being lost. This history save and restore process presumes a successful completion and does not occur on all error conditions. For more information, see the description of VERIFY= in How to Use.

The following topics are discussed on this page:

When to Use

Use this function to allocate a new data area or data areas. A data area must be initialized before CA Datacom®/DB can use it. This is necessary only once for any data area unless you modify the block size to accommodate changes.

In Simplify mode, the function expects MUF to be enabled. This provides control and protection. If MUF is not enabled, this function should wait for MUF to enable. If you are required to execute the function without MUF enabled, for example if it is needed to allow restart to execute, the function must follow a function that can only run with MUF not enabled or it must follow a function to acknowledge MUF is not enabled, with SET OPTION1=MUF_NOT_ENABLED. It is possible (but we do not recommend) to use SET OPTION1=MUF_ENABLED_OR_DISABLED.

Data Set Name

CA Datacom®/DB saves the data set name of the area in the Directory (CXX) at the time of the INIT. The data set name is then available for reporting. It is also available for dynamic allocation.

Multivolume INITs

Depending on operating system requirements and operating system maximums, a data area can exist as one or more extents on one or more volumes, . If initializing an existing data set (DISP=SHR or DISP=OLD), CA Datacom®/DB formats all currently allocated tracks for use. If initializing a new data set (DISP=NEW), CA Datacom®/DB requests and formats the primary allocation only if one volume is provided. If multiple volumes are provided, CA Datacom®/DB requests secondary allocations until space has been allocated on the number of volumes specified. For a description of how the operating system handles secondary allocations, see your operating system JCL manual.

VOLUMES=4multivolumeINITs

If the keyword VOLUMES= is specified with a number value that is less than the number of volumes provided, the INIT function only initializes the number specified in the VOLUMES= keyword. For example, for a DD statement with VOL=SER=(VOL001,VOL002,VOL003), without the VOLUMES= keyword DBUTLTY initializes 1 to 16 extents on VOL001, 1 to 16 extents on VOL002, and 1 (or more) extents on VOL003. But with the VOLUMES= keyword set as VOLUMES=2, DBUTLTY initializes 1 to 16 extents on VOL001 and one (or more) extents on VOL002. Unused extent possibilities on VOL002 and VOL003 are available for dynamic extend.

Successful Execution Requirements and Controls

Environmental Requirements when MULTUSE=NO, Simplify NO, or MUF down

  • The database cannot be open for update anywhere.
  • The database cannot be open in any MUF for read.
  • The database cannot have any table in unloading status.

Environmental Requirements when MULTUSE=NO Simplify YES and MUF enabled

  • The database can be open for update but must have no users.

Environmental Controls when MULTUSE=NO, Simplify NO, or MUF down

  • The database is opened for update.
  • The utility has no knowledge about current ACCESS database or area status.
  • The utility sets no ACCESS database or area status.

Environmental Controls when MULTUSE=NO, Simplify YES, and MUF enabled

  • The database is opened for update if not already.
  • Areas is closed if open.
  • The utility executes with every ACCESS database or area status.
  • The utility sets protection to block other incompatible DBUTLTY functions.

Environmental Requirements when MULTUSE=YES

  • The database cannot be open for update in the connected MUF.
  • The database cannot be open for update in another MUF or Single User job.
  • The database cannot have any table in unloading status.
  • The database ACCESS must be set OPTIMIZE and WRITE/UTLTY.
  • The area ACCESS must be set WRITE/UTLTY.
  • The area can have no table in an open User Requirements Table.
  • The area cannot have any other MULTUSE=YES utility executing.
  • The area must be closed.
  • When MULTUSE=YES, this function is not allowed against a Data Sharing MUF if more than one is executing.

Environmental Controls when MULTUSE=YES

  • The database is opened by MUF for update.
  • The utility sets ACCESS area OFF (utility set).
  • The utility sets INIT executing this MUF this database or area.

How to Use

You can execute this command in either Single User or with the MUF active. Execute the DBUTLTY function using the following command format:

►►─ INIT AREA=a,DBID=n ─┬───────────────────────┬─────────────────────────────►
                        └─ ,VERIFY= ─┬─ NO ◄ ─┬─┘
                                     └─ YES ──┘

 ►─┬────────────────────────┬─┬──────────────────┬────────────────────────────►
   └─ ,MULTUSE= ─┬─ NO ◄ ─┬─┘ └─ OPTION1=REINIT ─┘
                 └─ YES ──┘
 ►─┬──────────────┬─────────────────────────────────────────────────────────►◄
   └─ ,VOLUMES=n ─┘

Command

  • INIT
    Invokes the function to format areas for CA Datacom®/DB use.

Required Keywords

  • AREA=
    Identifies the data area to be formatted.
    If you specify AREA=*DA (an asterisk followed by the uppercase letters DA), all data areas in the database are initialized.
    • Limits:
      DATACOM-NAME of the area in the specified database or *DA for all data areas in the database
    • Default:
      (No default)
  • ,DBID=
    Identifies the database containing the area that is to be initialized.
    • Limits:
      DATACOM-ID of the database
    • Default:
      (No default)

Optional Keywords

  • ,MULTUSE=
    (For area level DBUTLTY control only.) In support of area level DBUTLTY control, specifying MULTUSE=YES in the INIT function for a data area allows a single area in a database to be initialized with no disabling of the other areas in the database. When MULTUSE=YES, the function executes in a format that is a combination of MUF and Single User modes. The database involved must be able to be opened for update in the MUF address space. The area, however, must have no tables open. Once begun, the function does not allow other tasks to open any tables in the area being processed. Other tables in the database, but not in the area, may be open for read or update in the same MUF. The actual data set open is performed in the utility region, and the JCL requirements are applied to the utility region.

    The operating system performs the catalog portion of the DD statement DISP option when the DD statement is removed. This occurs at job step termination. Therefore, if you were to create a new data set with an INIT, do not expect the MUF to correctly open this area until after the step completes. This restricts the DBUTLTY functions that succeed when following a catalog change.
    When you specify or allow the default of MULTUSE=NO in the INIT function for data areas, the function executes completely in Single User mode.
    For more information about area level DBUTLTY control, see Area Level DBUTLTY Control.

    • Limits:
      NO or YES
    • Default:
      NO
  • ,OPTION1=
    You can specify REINIT (re-initialize) for the OPTION1= keyword during the initialization of a data area. Specifying OPTION1=REINIT requires that you also specify VERIFY=YES.
    When using REINIT, the data set is re-initialized with the same number of tracks that were in use before the INIT, and no additional tracks are found or added to the data set during the INIT. When REINIT is not specified, the INIT closes the data set for update, opens the data set for output (and honors current, complete JCL specifications), closes the data set for output, and then reopens the data set for update.
    Adding space to an index or data area is normally accomplished using an EXTEND function, but it can be done during an INIT function as well. A benefit of the OPTION1=REINIT for z/OS users is that REINIT allows unused volumes to be added to data sets that do not have to be removed before an INIT.
    For example, if you are not using SMS, you could INIT an area on 3 volumes and load the area. You might then manually uncatalog the area and recatalog it with an additional volume or volumes. Those additional volumes would be available for any dynamic extend for the area that was needed, but to prevent the INIT from forcing the use of the volumes that were added solely for the use of dynamic extend, you would need to manually uncatalog the area before another INIT and recatalog it without any additional volumes.
    • Limits:
      REINIT
    • Default:
      (No default)
  • ,VERIFY=
    If you do not specify the VERIFY= option, or if you specify VERIFY=NO (the default), an INIT opens the data set for output, builds a new control block, and initializes the extents.
    If you specify VERIFY=YES, an INIT opens the data set for update, reads and updates an existing control block, and initializes the extents.
    Because a new control block is always built with VERIFY=NO, specifying VERIFY=YES when the INIT is not for a new data set brings several benefits, including the following:
    • Because an existing control block is read and updated instead of a new one being built, the data area history (in the control block) documenting activities such as backups and loads is not lost. Data area history information can be a valuable aid when troubleshooting various problems. Note that on some error conditions, the history can be lost.
    • VERIFY=YES prevents the unintentional overlaying of important information because of a JCL error, such as writing over files in PRODuction status that should have been in TEST status, or the inadvertent overlaying of the Directory (CXX) or Log Area (LXX).
    Note: Even with VERIFY=YES specified, the last extent and the number of extents is lost during an initialize.

    You can specify both VERIFY=YES and DISP=NEW, but if you specify both the VERIFY=YES is ignored.

    • Limits:
      YES or NO
    • Default:
      NO
  • ,VOLUMES=n
    The n in VOLUMES=n is the maximum number of volumes to initialize. Without the VOLUMES= option, the number of volumes having specific VOLSER information is initialized. The VOLUMES= option allows more volumes to be catalogued as part of the data set and available to an EXTEND or dynamic EXTEND, while being effectively held in reserve without a specific allocation.
    For example, you could specify VOLUMES=3 when using an INIT to initialize an area that needs 3 volumes, intending to only initialize the space on 3 volumes. But the JCL could specify 6 specific volumes, for example:

    VOL=SER=(VOL001,VOL002,VOL003,VOL004,VOL005,VOL006)

    In this example, volumes 4/5/6 are therefore not allocated or used during the INIT but are available to a dynamic extend. In this case, the extra volumes would not need to be removed before another INIT.

    • Limits:
      the number n of volumes to be catalogued
    • Default:
      (No Default)

Example JCL

The following shows the command to initialize the data Area DEM for database 1.

 
Note: Use the following as a guide to prepare your JCL. The JCL statements are for example only. Lowercase letters in a statement indicate a value you must supply. Code all statements to your site and installation standards. The DDNAME is required to be the area name and 3 character DBID for those bases 001 through 999; the area name and 4 character DBID for those bases 1000 through 5000.
 //jobname    See the previous note and Required JCL.
 //       EXEC PGM=DBUTLTY,REGION=2M
 //STEPLIB    See the previous note and Required JCL.
 //CXX      DD DSN=cxx.data.set,DISP=SHR           Directory data set
 //aaannn (for bases 001-999) DD DSN=aaa.data.set,DISP=SHR Data area DEM data set bases 1-999
 //aaannnn (for bases 1000-5000) DD DSN=aaa.data.set,DISP=SHR    Data area DEM data set bases 1000-5000
 //SYSIN    DD *                                   Command Input
           INIT     AREA=DEM,DBID=1
 /*

Sample Report

Following is a sample report page. For an example report header, see Sample Report Headers.

Sample Report INIT Data Area

                    CONTROL CARD(S)
                    .........1.........2.........3.........4.........5.........6.........7.........8
                    INIT AREA=DEM,DBID=1
 
                    FUNCTION=INIT
                       AREA=DEM
                       DBID=1

This page of the report shows the following:

  • The command exactly as entered.
  • An analysis of keywords encountered and expected. Any errors found are flagged with a note in the left margin.
  • Any messages related to syntax processing.

                   DEM - STATUS INFORMATION
 
                   DEVICE TYPE -    3380
                   BLOCK LENGTH -  1,024
                   BLOCKS/TRACK -     31
                  
                   BLOCKS IN USE -         1
                   BLOCKS UNUSED -       154
                   TOTAL BLOCKS -        155
                   TOTAL TRACKS -          5
                   PERCENT FULL -          1

This page of the report shows messages indicating the status of the data area at successful completion of the initialization.

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