For input files
The device type you enter on the FILEDEF command indicates the
device from which you want records read. It can be DISK, TERMINAL,
READER (for input from real cards or virtual cards), or TAPn (for
tape). Using the above example, if your input file is to be read from
your virtual card reader, the FILEDEF command might be as follows:
filedef inputdd reader
Or,
if you were reading from a tape attached to your virtual machine at
virtual address 181 (TAP1):
filedef inputdd tap1