ABCs of z/OS System Programming Volume 3 - IBM Redbooks

3.29 EATTR JCL DD statement example
If an EATTR value is not specified for a data set, the
following default data set EATTR values are used:
The default behavior for VSAM data sets is OPT
The default behavior for non-VSAM data sets is NO
A DD statement defines a new data set
Example allocates 10,000 cylinders to the data set
When the CONTIG subparameter is coded, the system
allocates 10,000 contiguous cylinders on the volume
//DD2 DD DSNAME=XYZ12,DISP=(,KEEP),UNIT=SYSALLDA,
// VOLUME=SER=25143,SPACE=(CYL,(10000,100),,CONTIG),
// EATTR=OPT
Figure 3-32 JCL example using the EATTR parameter
Using the EATTR parameter
OPT is the default behavior for VSAM data sets if EATTR(OPT) is not specified. For
non-VSAM data sets the default is that the data set cannot have extended attribute DSCBs
and optionally reside in EAS. This is equivalent to specifying EATTR(NO) on the command.
EATTR JCL example
In Figure 3-32, the DD statement defines a new partitioned data set. The system allocates
10,000 cylinders to the data set, of which one hundred 256-byte records are for a directory.
When the CONTIG subparameter is coded, the system allocates 10 contiguous cylinders on
the volume. EATTR=OPT indicates that the data set might be created with extended
attributes. With this option, the data set can reside in the extended address space (EAS) of
the volume.
Note: The EATTR value has no effect for DISP=OLD processing, even for programs that
might open a data set for OUTPUT, INOUT, or OUTIN processing. The value on the EATTR
parameter is used for requests when the data set is newly created.
Chapter 3. Extended access volumes 101