
226 Introduction to the New Mainframe: z/VSE Basics
iomode is for INPUT or OUTPUT mode. If you are only reading from a file, code
INPUT. If you are only writing to it, code OUTPUT or EXTEND. If you are both
reading and writing, code I-O.
Others like filename, recordname, fieldname (nn in the example), fieldlength, and
type are also specified.
9.4.2 COBOL relationship between JCL and program files
Example 9-4 depicts the relationship between JCL statements and the files in a
COBOL program. By not referring to physical locations of data files in a program,
we achieve device independence. That is, we can change where the data
resides and what it ...