Considerations for IMS-managed ACBs environment

When the IMS management of ACBs is enabled, IMS reads database descriptors (DBDs) from the IMS catalog instead of from the DBD library that is specified in the IMS DD statement.

Refer to the following JCL examples when you prepare IMS HP Unload JCL to run an unload job in an IMS-managed ACBs environment. For more information about coding IMS HP Unload JCL, see Basic job control language.

Example 1: Specifying the DFSDF= parameter and DBRC=Y

//UNLOAD   EXEC FABHULU,                        
//              MBR=FABHURG1,DBD=USERDBD,DBRC=Y,
//              PARM1='DFSDF=CAT'               
//G.PROCLIB DD DSN=IMS.PROCLIB,DISP=SHR       
//DBSAMP01  DD DSN=DBSAMP01.DATA1,DISP=OLD      
//SYSUT2    DD DSN=DBSAMP01.UNLOAD,DISP=(NEW,PASS),
//             SPACE=(CYL,(20,10))

DFSDF=CAT parameter is specified on the EXEC statement. This parameter specifies the DFSDFCAT member that enables IMS-managed ACBs. The name of the IMS.PROCLIB data set in which the DFSDFCAT member exists is specified on the PROCLIB DD statement.

You must allocate the catalog partition definition data set when unloading a database with DBRC=NO. To do so, add the DFSHDBSC DD statement or the DFSMDA member with the TYPE=CATDBDEF statement.

Example 2: Using the IMS Catalog Definition exit routine

//UNLOAD   EXEC FABHULU,                       
//              MBR=FABHURG1,DBD=USERDBD,DBRC=Y
//G.STEPLIB DD                                 
//          DD                                 
//          DD DSN=user.DFS3CDX0,DISP=SHR      
//DBSAMP01  DD DSN=DBSAMP01.DATA1,DISP=OLD     
//SYSUT2    DD DSN=DBSAMP01.UNLOAD,DISP=(NEW,PASS),
//             SPACE=(CYL,(20,10))

The DFS3CDX0 exit routine must be bound into IMS.SDFSRESL or a concatenated library.

You must allocate the catalog partition definition data set when unloading a database with DBRC=NO. To do so, add the DFSHDBSC DD statement or the DFSMDA member with the TYPE=CATDBDEF statement.