In addition to the 3592 physical WORM tape support, Release 1.6 of the TS7700 Virtualization Engine provides support for logical WORM (for both the TS7740 and the TS7720). Refer to APAR OA28632 (z/OS V1R9 and above) for more information. If the TS7700 is a multi-cluster grid, all clusters in the grid must be at a release level that supports logical WORM for the TS7700 to be WORM enabled. To request a logical WORM volume, an outboard data class policy must be defined (at the library) requesting logical WORM. This data class must then be assigned through the ACS routines, for a logical WORM request. A logical volume will become WORM when it is first mounted and written from load point. A volume will not take on the WORM attribute if user data had already been written to the volume. As with the 3592 physical WORM tape support, any attempt by the host to modify a previously written user data record of a logical WORM volume will be failed by the TS7700. With the 3592 WORM tape support, a volume is designated as WORM through usage of special WORM media types (MEDIA6, MEDIA8, MEDIA10, or MEDIA12). A logical volume (MEDIA1 or MEDIA2) will be designated as WORM, not by the usage of a special WORM media type, but when it is first mounted and written from load point. Refer to z/OS DFSMS OAM Planning, Installation, and Storage Administration Guide for Tape Libraries for more information.