Invalid mirror definition table...refers to unknown or duplicate drive.
  Run PREPARE.

     Occurs on:  SFT I, SFT II, TTS.  This is an Abend error.

     Meaning:    This error indicates that the mirror definition table
                 has been corrupted and contains information on
                 nonexistent or duplicate drives.  The mirror definition
                 table contains the drive mirror assignments.  This
                 error message is displayed if two separate drives
                 defined in the mirror definition table claim the same
                 mirror drive or if a mirror assignment refers to a
                 drive that is not installed on the system.  Although
                 SFT I does not support disk mirroring, it still uses
                 the information in the mirror definition table.

     Cause:      The most probable cause of this error is that the
                 mirror definition table stored on the disk has been
                 overwritten by other information.

     Solution:   The PREPARE utility should be run to re-setup the disk
                 mirror assignments and rebuild the mirror definition
                 table. Even though SFT I does not support disk
                 mirroring, PREPARE should be run to repair the mirror
                 definition table.