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Physical Mount Required
The host requested a specific volser or specified a category that was not
designated as a "Fast Ready" category. The volser needed to satisfy 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 a tape drive that the VTS
or TS7700 Virtualization Engine manages so that the recall operation can be
performed.
Demount Operations
The 3494 Tape Library 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 VTS or TS7700 Virtualization Engine. 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:
v A demount was 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.
v A demount was requested, but the volume has not been mounted.
This operation is used to cancel a mount operation that has not been started.
The library recognizes that because a demount request was received for a mount
that has not occurred, the host must not want the mount. Therefore, the two
requests cancel each other.
Eject Operations
An eject operation results in a physical cartridge being placed in a cell of an output
facility in the 3494 Tape Library. The type of output facility may be either the
convenience I/O station or the high-capacity output facility. The host specifies the
type of facility as part of the eject request. An eject request is considered complete
when the specified cartridge is placed in the cell of an output station. On
completion, the specified volume is removed from the Library Manager inventory.
Logical volumes that a VTS or TS7700 Virtualization Engine manages cannot be
ejected unless they are assigned to the Insert category or to a category designated
as "Fast Ready". Any host request to eject a logical volume not in the Insert
category or in a "Fast Ready" category will fail. An ejected logical volume is
removed from the Library Manager inventory.
Audit Operations
An audit uses the vision system to ensure that the physical cartridge associated
with the volser specified in the request is physically in the 3494 Tape Library
where expected. If the volser specified 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 specified 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.
If the volser specified is a logical volume in the Library Manager's inventory, the
Library Manager determines the physical volume on which the logical volume
resides and performs an audit of that physical volume. The audit operation is
Chapter 3. Operational Characteristics
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