DLI, DBB, and BMP region types and GSAM

To access GSAM databases, IMS builds its DLI control blocks using PSB and DBD information from PSBLIB, DBDLIB and ACBLIB. The source of the PSB and DBD information depends on the region type.

For DLI offline batch regions, IMS obtains PSB and DBD information from PSBLIB and DBDLIB. For DBB offline batch regions, IMS database management obtains PSB and DBD information from ACBLIB. For online batch regions (BMPs), IMS builds its DLI control blocks with information from ACBLIB. If an application is scheduled in a BMP region and the PSB associated with the application contains one or more GSAM PCBs, IMS scheduling obtains PSB information from ACBLIB and PSBLIB. In this case, the PSB in ACBLIB and PSBLIB must be the same. GSAM database management does not obtain PSB and DBD information from ACBLIB. Instead, GSAM database management obtains PSB and DBD information from PSBLIB and DBDLIB.

When you initialize a DLI, DBB or BMP region using GSAM, you must include an //IMS DD and GSAM DD statements. When DBB or BMP regions are not using GSAM, //IMS DD statements do not need to be included. To load PSBs and DBDs and build GSAM control blocks, you must include an //IMS DD statement. In the following figure, an example of the //IMS DD statement with data sets that are larger than 65535 tracks is shown.

//STEP       EXEC     PGM=DFSRRC00,PARM=[BMP|DBB|DLI],...'
//STEPLIB    DD       DSN=executionlibrary-name,DISP=SHR
//           DD       DSN=pgmlib-name,DISP=SHR
//IMS        DD       DSN=psblib-name,DISP=SHR
//           DD       DSN=dbdlib-name,DISP=SHR
//IMSACB     DD       DSN=acblib-name,disp=shr (required for DBB)
//SYSPRINT   DD       SYSOUT=A
//SYSUDUMP   DD       SYSOUT=A
//ddnamex    DD       (add DD statements for required GSAM databases)
//ddnamex    DD       (add DD statements for non-GSAM IMS databases 
                      for DLI/DBB)
//ddnamex    DD       DSNTYPE=LARGE,...
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