Indexed addressing option

Indexed Addressing allows for host bus adapter (HBA) drivers that only use Peripheral Device addressing to access SCSI devices attached to the interface card. This is done by use of a table, which is indexed by sequential LUN values, indicating selected BUS:TARGET:LUN devices. It is not possible in this mode to address the interface card as an interface card unit directly. The table has the structure as shown in Table 22.

The maximum size of the table is equal to the number of buses times the number of targets per bus, less one initiator ID per bus, times the number of LUNs per target.

The index table can be manually edited. A method is also provided to perform SCSI device discovery, and fill the table in the order that SCSI devices are discovered on the SCSI buses.

Table 22 Indexed addressing table

FCP LUN Value

SCSI BUS:TARGET:LUN

 

 

0

0:0:0

 

 

1

0:1:0

 

 

2

0:2:0

 

 

3

0:3:0

 

 

4

0:4:0

 

 

5

0:5:0

 

 

6

0:6:0

 

 

 

(0:7:0 occupied by Initiator ID)

 

 

7

0:8:0

 

 

(...)

(...)

 

 

13

0:14:0

 

 

14

0:15:0

 

 

15

1:0:0

 

 

16

1:1:0

 

 

17

1:2:0

 

 

(...)

(...)

 

 

SCC addressing option

When an interface card device is configured to use SCSI interface card Commands (SCC) addressing, the unit is capable of responding as an interface card device to the FCP Initiator, or routing the FCP request to a specified BUS:TARGET:LUN. When a request using the Peripheral Device addressing method is received (an FCP command with the LUN field with bits 7 and 6 of byte 0 are set to 0), the unit routes the request to the internal processor, which acts on the command directly. When a request using the Logical Unit addressing method is received (bits 7 and 6 set to 10b), the request is routed to the BUS:TARGET:LUN as specified in the defined field.

Host systems using SCC addressing will typically do initial device discovery using the Peripheral Device addressing method. On issuing an INQUIRY command to the interface card, the host will receive the interface card Inquiry data, indicating the device type as a interface card device (Inquiry data indicates device type is 0xC). The host will then know, on this basis, that subsequent commands to interface card attached devices will use the Logical Unit addressing method.

The host can perform discovery by either walking through the BUS:TARGET:LUN values as would a standard SCSI driver, or by issuing a REPORT LUNS command. This command is sent to the interface card (using the Peripheral Device addressing method), and the interface card returns a table indicating