File and Record Locking
- Indexed files do not detect or acquire locks if they are opened for output. This is regardless of whether you specify the WITH LOCK phrase
- Relative and sequential files cannot be locked exclusively
- Files which are opened for input can detect record locks, although the RM/COBOL documentation states that they cannot. When the RM directive is set under this COBOL system, record locks can still be detected by files opened for input
- The first record in sequential files opened for input-output is locked whenever any other record in that file is locked