Read-after-write check

A read-after-write check serves to detect recording errors when data is written to a disk. Because of the additional disk revolutions involved, this check significantly impairs system performance.

The user can activate a read-after-write check only for the current processing run, using either the WRCHK operand of the FILE/FCB macro or the WRITE-CHECK=*YES operand of the ADD-FILE-LINK command. This operand must be entered each time a read-afterwrite check is required, as it is not stored in the catalog entry.