Overrides

Start of change Normally, JCL specifications override data class specifications. However, the OVERRIDE SPACE attribute in the SMS data class allows you to specify whether the space attributes that are specified in the data class override corresponding attributes in the JCL. This exception applies to SPACE on the DD statements and also to dynamic allocation and IDCAMS DEFINE CLUSTER control statements. The OVERRIDE SPACE attribute value in the SMS data class can be YES or NO; the default is NO. End of change

When OVERRIDE SPACE takes the default value 'NO', explicit specification of SPACE on the DD statement overrides both the SPACE and the AVGREC values specified in the data class.

An ACS routine can override the data class that you specify on the DATACLAS parameter.

Attributes obtained with the LIKE and REFDD parameters override the corresponding attributes in the DATACLAS parameter except when the data class assigned specifies 'YES' for the OVERRIDE SPACE attribute.

When OVERRIDE SPACE data class attribute takes the value 'YES', the JCL SPACE parameters are replaced with the data class SPACE related attributes.

For Non-VSAM data sets, the following data class attributes are used to override the JCL space specifications:

AVGREC
AVGVAL
Primary quantity
Secondary quantity
Directory blocks (specify 0 for PS , non-zero for PO)

For VSAM data sets , the following data class attributes are used to override user specifications:

AVGREC
AVGVAL
Primary quantity
Secondary quantity
Cisize Data
%Freespace CI
%Freespace CA

However, depending on the Recfm, Cisize data, %freespace values can be ignored.