Sense Data, Unit Attention and Deferred Errors are maintained for each initiator. Mode Parameters are common to all initiators.

The untagged queuing model implemented by the drives guarantees that all commands are executed in strict order of receipt. Certain non-media access type commands, such as TEST UNIT READY, INQUIRY, REQUEST SENSE and REPORT LUNS, are implicitly allowed to queue-jump other media access type commands, such as REWIND.

The parallel SCSI drive supports the full command queuing model with a queue depth of 1 (necessary for connectivity purposes). The FC drive supports the basic queuing model with a queue depth of 4. See “Standard Inquiry Data format (LUN0)” on page 40 for details of the BQue and CmdQue bits which define this support.

Fibre Channel operation

NOTE: This applies only to Fibre Channel drives.

The following sections have information specific to Fibre Channel operation:

•“Fibre Channel Logical Unit Control mode page” on page 84

•“Fibre Channel Port Control mode page” on page 85

•“Vital Product Data pages” on page 44

Fibre Channel addressing

Before describing HP’s implementation of Fibre Channel addressing, the concepts of Names and Addresses need to be clarified.

Names

Names are 64-bit identifiers assigned permanently to the tape drive during manufacture. They are commonly referred to as World Wide Names since they must be guaranteed unique. The names are typically used for identifying the device to operating systems, since addresses are assigned dynamically. There at least eight different name formats distinguished by the Network Address Authority (NAA). Only one is used on HP Ultrium drives. This is the IEEE Registered Name (NNA=5) and has the following format:

This name is made up of three fields:

•NAA Identifier (4 bits). “5” indicates a IEEE Registered Name.

18 Interface Implementation