COBOL Manual for TNS/E Programs (H06.08+, J06.03+)

for a line sequential file:
outfile
is the file description file name of a file to open in OUTPUT mode, for write operations
only.
TIME LIMITS, SHARED, PROTECTED, EXCLUSIVE, sync, NO REWIND
are the same as described earlier for infile.
I-O
specifies that the file or files in i-o-file-description are being opened for reading
or writing.
i-o-file-description
for a sequential, relative, indexed, or queue file:
I-O mode is not supported for line sequential files.
iofile
is the file description file name of a file to open in I-O mode, for both read and write
operations.
TIME LIMITS, SHARED, PROTECTED, EXCLUSIVE, sync
are the same as described earlier for infile.
EXTEND
specifies that the file or files in extend-file-description are being opened for writing
additional data following any existing data.
extend-file-description
for a sequential, relative, indexed, or queue file:
378 Procedure Division Verbs