If your IMS system is already configured to use the IMS catalog, you enable the IMS management of ACBs without having to enable the IMS catalog at the same time.
If you have recently migrated to a new release of IMS, make sure that the IMS system is stable and running with the IMS catalog enabled.
In data-sharing environments, evaluate the impact of enabling IMS-managed ACBs on your current configuration. If all IMS systems in the data-sharing group share a single IMS catalog, the effect of enabling the IMS management of ACBs is similar to having all IMS systems share a single ACB library.
Make sure that the ACB libraries that you provide as input to the IMS Catalog Populate utility (DFS3PU00) contain all of the ACBs that are currently active in
the IMS system. The following catalog resources must be present
in one of the ACB libraries:
- DFSCD000
- DFSCP000
- DFSCP001
- DFSCX000
- DFSCPL00
Do not enable the IMS management of ACBs in the <CATALOG>
section of the
DFSDFxxx member until after the DFS3PU00 utility successfully creates the IMS
directory and loads it with the active ACBs. If necessary, you can explicitly specify
ACBMGMT=ACBLIB
in the <CATALOG>
section of the
DFSDFxxx PROCLIB member until the IMS directory is ready to be used. IMS will
issue message DFS7443E and terminate with a 0071 abend during IMS initialization if IMS managed ACBs
is enabled and one or more of the following required catalog resources is not present in the
directory: DFSCD000, DFSCP000, DFSCP001, DFSCX000 and DFSCPL00.
The default access level of the IMS catalog changes from ACCESS=READ
to
ACCESS=UPDATE
when the IMS management of ACBs is enabled. You can specify the access level explicitly in the <CATALOG>
section of the
DFSDFxxx member or change it later by using the UPDATE DB or
/START DB command.
Recommendations: Keep the DBD and PSB source statements and the ACB,
DBD, and PSB libraries intact until you are certain that you will
not need to fall back to the use of installation-managed ACBs.
Similarly,
do not delete from any JCL the DD statements that refer to the ACB,
DBD, or PSB libraries until you are certain that you will not need
to fall back.
If your IMS catalog is not already configured to use SMS-managed data sets, enable SMS-managed data sets now. The IMS catalog options for SMS-managed data sets are specified in the <CATALOG>
section
of the DFSDFxxx member.
To enable the IMS management of ACBs when you are already using the IMS catalog follow these steps:
- Optional:
Specify a high-level qualifier for the IMS directory data sets on the SYSDSHLQ parameter in a
CATDSHLQ DFSMDA macro statement.
When the SYSDSHLQ parameter is not specified in the dynamic allocation macro (DFSMDA)
statement, IMS derives the high-level qualifier for the directory data set, the boot strap data set,
and the staging data set from the data set name prefix of the IMS catalog database data sets.
-
Code the JCL and input control statements of the DFS3PU00
utility:
- On the EXEC parameter in the JCL for the DFS3PU00 utility, specify PSB DFSCP001 for update access to the IMS catalog or, if you need to delete and reload the IMS catalog, you can use the load PSB, DFSCPL00, instead, which directs the DFS3PU00 utility to update the IMS catalog in load mode.
- Specify one or more ACB libraries that contain the currently
active ACBs by using the IMSACBnn DD statements.
- Specify the
MANAGEDACBS=SETUP
control statement by using the SYSINP DD statement.
-
Run the DFS3PU00 utility to set up
the IMS catalog to manage ACBs. Make sure that you enabled the
IMS catalog and specified the options for the IMS catalog as necessary in CATALOG and CATALOGxxxx sections of the DFSDFxxx member before using the DFS3PU00 utility. Set
ACBMGMT=ACBLIB
in the CATALOG and CATALOGxxxx section of the DFSDFxxx member until
the IMS directory data sets are populated .
The DFS3PU00 utility inserts any new or modified instances of DBDs or PSBs into the IMS catalog and loads all ACBs into the IMS directory data sets, which are IMS-managed
system data sets that serve a similar purpose in the IMS system
as the ACB library data sets. After an ACB is added to the IMS
directory, the corresponding resources in the IMS catalog are
flagged as active.
-
For batch application programs,
add the IMS catalog and ACB management definitions to the batch
environment by either updating the execution JCL to reference the DFSDFxxx
PROCLIB member or by using the IMS Catalog Definition exit
routine (DFS3CDX0), which provides the definitions without requiring you to modify the JCL.
- In the
<CATALOG>
section of the DFSDFxxx member in the IMS.PROCLIB data set, specify ACBMGMT=CATALOG
.
- Restart all IMS systems that use the DFSDFxxx member
in which
ACBMGMT=CATALOG
is specified.
If you have utilities, tools, or
processes that continue to require the ACB, DBD, and PSB libraries, the library members must match
the resources that are flagged as active in the IMS catalog. To
generate matching libraries after IMS is managing the ACBs, use
the IMS Catalog Database Library utility (DFS3LU00).Consider
setting the CATALOG field of the RECON data set if you need DBRC to read DBD information from an IMS catalog registered with DBRC. You can set the CATALOG field by
using the CHANGE.RECON command. If you do not specify the field, DBRC reads DBD information from the
DBDLIB. For more information, see DBRC access to DBD information when IMS manages ACBs.