When using ANSI'74 or ANSI'85 file status codes, run-time system returns extended file status codes if the extended file status is more specific.
Extended file status codes are of the form:
9/nnn
where nnn is a numeric value that is the same as the numeric value of the corresponding run-time system error. For example, if an extended file status code of 9/029 is returned, run-time system error COBRT029 (Attempt to delete open file) provides more information about the cause.