Mode Sense 6 (1Ah)

The Mode Sense 6 command (1A) enables the library to report its operating mode parameters to the initiator. The initiator can request one page or all pages of the mode parameters.

The Mode Sense (6) command only supports the Element Address Assignment (1Dh) and Device Capabilities (1Fh) pages. A library can be dynamically changed by the administrator using the GUI. Such changes include:

increasing or decreasing the number of storage elements
increasing or decreasing the number of import / export elements
adding or removing drives

Whenever the administrator makes any of these changes, the system presents a Unit Attention to the client application with the following sense information:

Sense Key 6h (Unit Attention) ASC / ASCQ 2Ah / 01h (Mode Parameters Changed)

Upon receipt of this Unit Attention, the client application should re-configure the library by using information returned by the Mode Sense command.

Figure 3-12 Descriptor Block - Mode Sense 6 (1Ah)

Description of "Figure 3-12 Descriptor Block - Mode Sense 6 (1Ah)"

DBD (Disable Block Descriptors)

Set to 1 to indicate that block descriptor should not be returned.

Page Control

Defines the type of parameters to be returned for the Mode Sense command, values include:

0h (00b) = Current Values: The library returns the current parameter values. Since Mode Select is not supported, the current values will always be equal to the default values.
1h (01b) = Changeable Values: Not supported. The command terminates with Check Condition status and sense key of Illegal Request (5h) and ASC set to Invalid Field in CDB (24h).
2h (10b) = Default Values: The library returns the default values. Since Mode Select is not supported, the default values will always be equal to the current values.
3h (11b) = Saved Values: The library returns the saved values. Not supported. The command terminates with Check Condition status and sense key of Illegal Request (5h) and ASC set to Invalid Saving Parameters Not Supported (39h).

Page Code

Specifies which pages the library returns, including:

1Dh = Element Address Assignment page
1Fh = Device Capabilities page
3Fh = All pages (in the above order)

SubPage Code

Not supported.

Allocation Length

Specifies the length of the parameter list the library returns. The maximum length is 2Ch (44d) bytes.The length varies based on the Page Code selected:

4 bytes for the parameter list header (always present)
20 additional bytes for the Element Address Assignment page
20 additional bytes for the Device Capabilities page

The library transfers the number of bytes specified by the Allocation Length or the available Mode Sense data, whichever is less.

Mode Sense Parameter Header

Figure 3-13 Descriptor Block - Mode Sense Parameter Header

Description of "Figure 3-13 Descriptor Block - Mode Sense Parameter Header"

Mode Data Length: The bytes of parameter information available regardless of the allocation length. This value excludes the Mode Data Length byte, but includes three additional bytes (for Mode Sense 6-byte) or six additional bytes (for Mode Sense 10-byte) and the length of any mode pages that follow.
Block Descriptor Length: 00h = the library does not support block descriptors.

Element Address Assignment Page

Figure 3-14 Descriptor Block - Element Address Assignment Page

Description of "Figure 3-14 Descriptor Block - Element Address Assignment Page"

PS (Parameters Savable): Specifies that the library cannot save this page to non-volatile memory and returns a value of 0.
Page Code: Identifies the Element Address Assignment mode page and returns a value of 1Dh.
Parameter Length: Indicates the amount of element address data following this byte and returns a value of 12h.
First Medium Transport Element Address: Identifies the address of the robot and returns a value of 0h.
Number of Medium Transport Elements: Identifies the number of hands within the library and returns a value of 0001h.
First Storage Element Address: Identifies the starting address of the cartridge tape storage cells. The default starting address is 3E8h (100d).
Number of Storage Elements: The number of data cartridge cells in the library or partition. The total number of cartridge tape storage cells depends on how the library is configured.
First Import/Export Element Address: Identifies the address of the first Import/Export element. The default starting address is 000Ah (10d).
Number of Import/Export Elements: Identifies the total number of import/export cells.
First Data Transfer Element Address: Identifies the address of the first tape transport installed in the library. The default address is 1F4h (500d).
Number of Data Transfer Elements: Identifies the number of tape drives in the library, and the library returns the configured count.

Device Capabilities Page

DT — Data Transfer Element (drive)
I/E — Import/Export Element (CAP cells)
ST — Storage Element (cartridge storage cell)
MT — Medium transport (robot hand)

Figure 3-15 Descriptor Block - Device Capabilities Page

Description of "Figure 3-15 Descriptor Block - Device Capabilities Page"

PS (Parameters Savable): The library returns 0.
Page Code: 1Fh = The Device Capabilities mode page.
Page Length: 12h = 18 bytes of device capabilities data to follow.
StorDT: 1 = A tape drive can function as element storage.
StorI/E: 1 = A CAP cell can function as element storage.
StorST: 1 = A cartridge cell can function as element storage.
StorMT: 0 = The robot hand cannot function as element storage. You cannot use the robot as the source or destination of a move.
MT > DT, MT > I/E, MT > ST, MT > MT, ST > MT, I/E > MT, DT > MT: 0 = The robot hand (MT) cannot be the source or destination of a move.
ST > DT, ST > I/E, ST > ST, I/E > DT, I/E > I/E, I/E > ST, DT > DT, DT > I/E, DT > ST: 1 = Tape drives (DT), CAP cells (I/E), and cartridge cells (ST) are valid sources or destinations for a move.
All <> Parameters: 0 = The library does not support the exchange medium command.