Prevent Allow Medium Removal - 1Eh
What the Library Does With This Command
The library will prohibit movement of media to an Import/Export element when media removal has been prevented. MOVE MEDIUM commands requesting such a move will be rejected with a Check Condition indicating Medium Removal Prevented. This command does not control locking or unlocking of a mailbox. The library automatically locks mailboxes during robotic access, and unlocks them afterwards.
While media removal is prevented, importing of media can still occur. The medium removal setting does not persist across power cycles of the library.
Any initiator issuing this command to allow medium removal (Prevent set to 00b) will allow medium removal for all initiators. This is done to maintain compatibility with certain bridged environment behavior (e.g., Fibre Channel to Parallel SCSI).
The prevention of medium removal condition terminates after:
-
one of the following occurs for each I_T nexus that had previously prevented medium removal:
- successful completion of a PREVENT ALLOW MEDIUM REMOVAL command with the PREVENT field set to 00b; or
- an I_T nexus loss.
- a power on
- a hard reset
- a logical unit reset
Command Usage
In conjunction with keyed access to the physical library doors, this command can be used to secure the library against unauthorized removal of media.
Prevent Allow Medium Removal CDB Format
The PREVENT ALLOW MEDIUM REMOVAL CDB format is shown in the following table.
Table 1: PREVENT ALLOW MEDIUM REMOVAL CDB format
|
Bit Byte |
7 |
6 |
5 |
4 |
3 |
2 |
1 |
0 |
|
0 |
Op Code (1Eh) |
|||||||
|
1 |
Logical Unit Number |
Reserved |
||||||
|
2 |
Reserved |
|||||||
|
3 |
Reserved |
|||||||
|
4 |
Reserved |
Prevent |
||||||
|
5 |
Control |
|||||||
| Field | Description |
|---|---|
| Prevent |
This field controls medium removal as follows:
|
