/HIGHWATER (default) /NOHIGHWATER Applies to Files-11 On-Disk Structure Level 2 (ODS-2) and Level 5 (ODS-5) disks only. Sets the file high-water mark (FHM) volume attribute, which guarantees that users cannot read data that they have not written. You cannot specify the /NOHIGHWATER qualifier for magnetic tape. The /NOHIGHWATER qualifier disables FHM for a disk volume.