In this statement, you must define the output data set that the external writer will use. The generalized format for the DD statement is:

//IEFRDER  DD  UNIT=device,LABEL=(,type),                          X
//             VOLUME=(,,,volcount),DSNAME=anyname,                X
//             DISP=(NEW,KEEP),DCB=(list of attributes),           X
//             UCS=(code[,FOLD][,VERIFY]),                         X
//             FCB=(image-id[,ALIGN]|[,VERIFY])

The ddname must be IEFRDER, as shown. The parameter requirements are as follows:

UNIT=device

This specifies the printer, tape, card punch, or DASD device on which the output data set is to be written.

LABEL=type

This describes a data set label, if one is needed (for tape data sets only). If this parameter is omitted, a standard tape label is used.

VOLUME=(,,,volcount)

Needed for tape data sets only, this parameter limits the number of tape volumes that this external writer can use during its entire operation.

DSNAME=anyname

This specifies a name for the output data set, so later steps in the procedure can refer to it. The data set name is required for the disposition of KEEP.

DISP=(NEW,KEEP)

The disposition of KEEP prevents deletion of the data set (tape and DASD only) at the end of the job step.

DCB=(list of attributes)

The DCB parameter specifies the characteristics of the output data set and the buffers. The BLKSIZE and LRECL subparameters are always required. The BUFL value, if you do not code it, is calculated from the BLKSIZE value. Other subparameter fields may be coded as needed; if they are not, the defaults are the QSAM default attributes. These are:

BUFNO—

Three buffers for the 2540 punch; two buffers for all other devices.

RECFM—

U-format, with no control characters.

TRTCH—

Odd parity, no data conversion, and no translation.

DEN—

Lowest density.

OPTCD—

Printer data checks are suppressed, and “select translate table” characters are printed as data. The IBM external writer does not support OPTCD=J, a printer dependent specification.

UCS=(code[,FOLD][,VERIFY])

This specifies the code for a universal character set (UCS) image to be loaded into the UCS buffer.

FOLD causes bits 0 and 1 to be ignored when comparing characters between the UCS and print line buffers, thereby allowing lowercase alphabetic characters to be printed (in uppercase) by an uppercase print chain or train.

VERIFY causes the specified UCS image to be printed for verification by the operator.

The UCS parameter is optional, and is valid only when the output device is a 1403, a 3211, or a 3203-5 printer.

FCB=(image-id[,ALIGN]|[,VERIFY])

This causes the specified forms control buffer (FCB) image to be loaded into the FCB. ALIGN and VERIFY are optional subparameters that allow the operator to align forms. In addition, VERIFY causes the specified FCB image to be printed for visual verification. The FCB parameter is valid only for a 3203-5, 3211, or 3800 printer; otherwise, it is ignored.