The IBM version of EPIO uses the input/output package IOPACK (Z300 in the CERN Program Library). DD names for the EPIO units are of the form
IOFILEnn nn = 1 to 99with
DCB=(RECFM=U,BLKSIZE=iiii)
The default version of EPIO does not allow concatenation of data sets but this can easily be changed by setting status word 25 to non-zero;
CALL EPSETW(LUN,25,1,IERR)
To access multiple logical units on the same physical unit
using "UNIT=AFF" requires a "CALL \Rind{EPRWND"}
in addition to EPDROP, so
that the unit is properly closed. The details for reading multifile
labelled tapes are in the description of EPREAD.