z/OS DFSMS OAM Planning, Installation, and Storage Administration Guide for Tape Libraries
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Fast response for nonspecific mount requests

z/OS DFSMS OAM Planning, Installation, and Storage Administration Guide for Tape Libraries
SC23-6867-00

When a nonspecific mount is requested, data is written from the beginning of the tape, overwriting any existing data on the tape. Within a VTS system, a nonspecific mount request is satisfied by accessing the data fragment in the tape volume cache associated with the virtual volume selected by the library manager to satisfy the request. No recall of the data from the previous usage of the volume is performed because the fragment contains the label information needed by the host tape management software to validate the use of the volume for a nonspecific mount request. The system signals the host that the mount is complete when the fragment is accessed. The result is a very low mount response time because no physical movement or mounting of a cartridge is involved.

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