Do
not specify DCB parameters RECFM, LRECL, or BLKSIZE; the external
writer will allocate them with record format VB and a system-optimal
blocksize and logical record length. For trace data sets on disk,
we recommend a minimum of 10 cylinders (3390). Secondary extents are
ignored unless the NOWRAP option is specified when the external writer
is started. For example:
// EXEC PGM=IEFBR14
//TRACE DD DSN=SYS1.MVSS14.WAS390.CTRACE,UNIT=3390,VOL=SER=HPK19A,
// SPACE=(CYL,(20,0)),DISP=(NEW,CATLG),DCB=DSORG=PS