Defaults

If no REGION parameter is specified, the system uses the REGION parameter specified on each EXEC statement. If no EXEC statement REGION parameter is specified, the system uses a job step installation default specified at JES initialization.

If your installation does not change the IBM-supplied default limits in the IEALIMIT or IEFUSI exit routine modules, then specifying various values for the region size has the following results:

A value equal to 0K or 0M — gives the job all the storage available below and above 16 megabytes. The resulting size of the region below and above 16 megabytes is installation-dependent. When REGION=0K/0M is specified, the MEMLIMIT is set to NOLIMIT.
Note: This may cause storage problems. See the Considerations When Using the REGION parameter section for more information.
A value greater than 0K or 0M and less than or equal to 16,384K or 16M — establishes the size of the private area below 16 megabytes. If the region size specified is not available below 16 megabytes, the job step abnormally ends with an ABEND822. The extended region size is the default value of 32 megabytes.
A value greater than 16,384K or 16M and less than or equal to 32,768K or 32M — gives the job all the storage available below 16 megabytes. The resulting size of the region below 16 megabytes is installation-dependent. The extended region size is the default value of 32 megabytes.
A value greater than 32,768K or 32M and less than or equal to 2,096,128K or 2047M — gives the job all the storage available below 16 megabytes. The resulting size of the region below 16 megabytes is installation-dependent. The extended region size is the specified value. If the region size specified is not available above 16 megabytes, the job step receives any storage available above 16 megabytes, up to the requested amount, and the resulting size of the region above 16 megabytes is installation-dependent.