The Inquiry data for a logical library is unique. It does not report that it is a known real library type. Additionally, the device identification page uses a NAA type 6 format using the logical library unique serial number as part of the vendor specific extension. This provides a way for clients to uniquely identify a library regardless of which target port the device is presented on.

Serial numbers for logical libraries consist of 12 ascii numbers. The format is SSSSSSSSNNNN where:

• SSSSSSSS is the unique software serial number of the system

• NNNN is the number of the library partition within the system (0-9999)

If an Inquiry command is received from a host initiator on a lun that is not currently mapped to a logical library, Inquiry returns a response with the Peripheral Qualifier set to 011b and Peripheral Device Type set to 1fh. Lun mapping is established by an administrator using the GUI.

The Mode Sense (6) command supports the Element Address Assignment (1Dh) and Device Capabilities (1Fh) pages only.

Move Medium commands that do not involve a drive element complete much faster for a logical library than for a physical library.

Move Medium to/from drive elements cause real robotic activity in the physical library. The time required before completion of the move is reported depends on the Fast Load setting at the time the command is received (this setting is found under "Preferences" in the ACSLS GUI).

Move Medium commands to/from import export elements behave differently than a real library. These differences are described in Import/Export Elements.

Since a logical library does not contain a physical CAP, this command is supported for compatibility but always returns “success".

The format of the Primary Volume Tag Information field can be in one of four formats, 6 character, 8 character suffix, and 8 character prefix. The format to be used is an attribute of the logical library that can be set by the administrator using the GUI. This is described in detail under the VolTag field of the ReadElementStatus CDB in the SCSI Commands chapter.

The system presents each logical library as a separate LUN on one of the systems' fibre channel target ports. The system provides LUN masking by allowing only specified initiators access to logical libraries. Initiators are identified using their FC world wide port name (WWPN). Using the GUI, an administrator must establish a mapping between an initiator (I), a target port (T), and a LUN (L). These mappings are saved by the system so that the logical library will always be presented on the same target port and LUN for the initiator. Each initiator is given its own LUN space starting with LUN 0. It is important to note that logical libraries can appear on LUNs other than 0. The first library mapped to an initiator will be assigned LUN 0, the next (on the same target port) will be assigned LUN 1 and so on.

The Report LUNs command will report the LUNs available to the requesting initiator. The command response includes the LUN number for each logical library that has been mapped for the requesting initiator. The LUN numbers are not guaranteed to be consecutive.

Whenever a mapping change is made by an administrator using the GUI, the system raises the following unit attention to the affected initiator:

• Sense Key 6h (Unit Attention)

• ACS / ACSQ 3Fh / 0Eh (Report LUNS Data Has Changed)

Logical libraries use an FC-2 conforming transport that provides autosense. This means that sense data for a failed command is always returned with a Check Condition status in the command response and is never saved by the target. Therefore, Request Sense will always return Sense Data with a Sense Key set to No Sense and ASC/ASCQ fields set to 0. The Request Sense command still documents all the Sense Data that can be returned from the other commands.

The Reserve and Release commands are purposely not supported in ACSLS 8.2. Each logical library can be mapped to a maximum of one initiator. Therefore, every logical library is exclusively owned by a single initiator and Reserve/Release would have no meaning. These commands are rejected with CHECK_CONDITION.