Defines a dataset (file) for the step: ```jcl //INFILE DD DSN=PROD.TRANS.DAILY,DISP=SHR //OUTFILE DD DSN=PROD.TRANS.POSTED, // DISP=(NEW,CATLG,DELETE), // SPACE=(CYL,(50,10),RLSE), // DCB=(RECFM=FB,LRECL=200,BLKSIZE=0) //SYSOUT DD SYSOUT=* ```