IBM Magstar 3494 Demount Operations, Eject Operations, Audit Operations, Physical Mount Required

Physical Mount Required

The host requested a speci®c volser or speci®ed a category that was not designated as a ªFast-Readyº category. The volser needed to satisfy that the mount operation is not resident in the tape volume cache and must be recalled from the physical tape. The library manager directs the cartridge accessor to move the required physical volume to one of the 3590 tape drives managed by the VTS so the recall operation can be performed.

Demount Operations

The 3494 performs a physical demount operation whenever a volume is unloaded from a physical tape drive. A similar operation occurs for the virtual tape drives within a Virtual Tape Server. When a virtual volume is unloaded from a virtual tape drive, a logical demount operation is performed.

The following are two types of demount operations:

vA demount has been requested and the volume is currently at the tape drive.

For a physical demount, this operation is used to move a volume from a tape drive to a storage cell. When the volume is placed in the storage cell, the demount is considered complete.

For a logical demount, this operation updates the status of the virtual volume in the library manager database to indicate that it is no longer mounted. No physical movement of a volume is involved.

vA demount has been requested and the volume has not yet been mounted.

This operation is used to cancel a mount operation that has not been started. The library recognizes that since a demount request has been received for a mount that has not yet taken place, the host must not really want the mount to take place. Therefore, the demount request and the mount request cancel each other.

Eject Operations

An eject operation results in a physical cartridge being placed in a cell of an output facility in the library. The type of output facility may be either the Convenience Input¤Output Station or the High-Capacity output facility and is speci®ed by the host as part of the eject request. An eject request is considered complete when the speci®ed cartridge is placed in the cell of an output station. On completion, the speci®ed volume is removed from the library manager inventory.

Logical volumes managed by a Virtual Tape Server cannot be ejected from the library unless they are assigned to the Insert category or a category designated as a ªFast-Readyº category. Any host request to eject a logical volume not in the Insert category or a ªFast-Readyº category will fail. An ejected logical volume is removed from the library manager inventory.

Audit Operations

The purpose of an audit is to ensure (by using the vision system) that the physical cartridge associated with the volser speci®ed in the request is physically in the library where expected. If the volser speci®ed in the request is a physical volume that is in the library manager's inventory, the audit operation checks the external label of the cartridge in the storage cell speci®ed in the library manager database. It must match what is in the database. If the volume is mounted on a tape drive, the audit is held until the volume is demounted and returned to its storage cell.

56Magstar 3494 Tape Library Operator Guide