Using DD statements

A DFSORT job always requires DD statements after the EXEC statement. DD: statements fall into two categories

System DD statements (discussed in detail in System DD statements)
Program DD statements (discussed in detail in Program DD statements).

System DD statements, and some program DD statements, are usually supplied automatically when you use a cataloged procedure. Others you must always supply yourself.

The DD statement parameters, the conditions under which they are required, and the default values, are summarized in Table 1. The subparameters of the DCB parameter (a DD statement parameter) are described similarly in Table 2.

Note:

Performance is enhanced if the LRECL subparameter of the DCB is accurately specified for variable-length records. The maximum input record length you can specify for your particular configuration is given in Data set notes and limitations.
When using DFSORT applications, FREE=CLOSE cannot be used on any DD statements except DFSPARM.

Table 1. DD Statement Parameters Used by DFSORT
DD Statement Parameters Used by DFSORTParameter	When Required	Parameter Values	Default Value
{AMP \| BUFSP}	When password-protected VSAM data sets are used and the password is supplied through E18, E38, or E39.	Minimum buffer pool value given when creating the data set.	None.
DCB	Required when 7-track tape is used; for input on tape without standard labels; and when the default values are not applicable.	Specifies information used to fill the data control block (DCB) associated with the data set.	(See separate subparameters in Table 2.)
DISP	When the default value is not applicable.	Indicates the status and disposition of the data set.	The system assumes (NEW, DELETE).
DSNAME or DSN	When the DD statement defines a labeled input data set (for example, SORTIN), or when the data set being created is to be kept or cataloged (for example, SORTOUT), or passed to another step.	Specifies the fully qualified or temporary name of the data set.	The system assigns a unique name.
LABEL	When the default value is not applicable.	Specifies information about labeling and retention for the data set.	The system assumes standard labeling.
SPACE	When the DD statement defines a new data set on disk.	Specifies the amount of space needed to contain the data set.	See z/OS MVS JCL Reference.
UNIT	When the input data set is neither cataloged nor passed or when the data set is being created.	Specifies (symbolically or actually) the type and quantity of I/O units required by the data set.	See z/OS MVS JCL Reference.
VOLUME or VOL	When the input data set is neither cataloged nor passed, for multireel input or when the output data set is on disk and is to be kept or cataloged.	Specifies information used to identify the volume or volumes occupied by the data set.	See z/OS MVS JCL Reference.

Table 2. DCB Subparameters Used by DFSORT
DCB Subparameters Used by DFSORTSubparameter	Condition When Required	Subparameter Values	Default Value
BUFOFF	When processing data in ASCII format.	Specifies the length of the buffer offset or specifies that the buffer offset is the block length indicator.
DEN	When the data set is located on a 7-track tape unit.	Specifies the density at which the tape was recorded.	800 bpi
OPTCD	When processing data in ASCII format.	Specifies that the tape processed is in ASCII format.
TRTCH	When the data set is located on a tape device with IDRC and system IDRC is not used.	Specifies whether data set is compacted.	System default option.
BLKSIZE ^1,²	When the DCB parameter is required and the default value is not suitable except on SORTWKdd statements.	Specifies the maximum length (in bytes) of the physical records in the data set.	For old data sets, the value in the data set label. For new output data sets, appropriate values based on the input data set or RECORD statement values. Unless SDB=NO is in effect, Blockset uses the system-determined optimum block size when the output data set block size is zero. Applications which require a specific output data set block size should be changed to specify that block size EXPLICITY. No default if input on unlabeled tape or BLP or NSL specified.
LRECL ^2,³		Specifies the maximum length (in bytes) of the logical records in the data set.
RECFM		Specifies the format of the records in the data set.