ATTO Technology 2100R, 2200R/D, 3200R manual Bit Number Address Address Method Specific Definition

ATTO Technology, Inc. ATTO FibreBridge Installation & Operation Manual

Bit Number

15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
Address						Address Method Specific Definition
Method

Bits 15-14 contain the Address Method code. This code is used to determine how the remaining 14 bits are to be interpreted by SCSI devices. The following table defines the available Addressing Methods.

Address Method Code
	Description
00b	Peripheral device addressing method
01b	Virtual device addressing method
10b	Logical unit addressing method
11b	RESERVED

An overview of the three defined Addressing Methods is given below. The fields are listed as defined in the SAM-2 specification. Details of each Addressing Method are discussed later in this document.

These Address Methods provide alternative user definable paths to SCSI devices. The Peripheral Device Addressing Method (PDAM) is the predominant method and is what is used in the examples that follow. Since by definition, bits 15-14 are 00, it is the only method that can be used by host/environments supporting <16 bits of LUN addressing. If the host/environment can support 16 bits, then any of the 3 addressing methods can apply.

Peripheral Device Addressing Method

Bit Number

15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
0	0			Bus	Identifier						Target	/ LUN

By definition, PDAM address 0 (bus = target = LUN = 0) selects the FibreBridge.

The Target field identifies the SCSI ID of the addressed SCSI device. The LUN field will select the logical unit in the addressed target. Since the SCSI Architectural Model – 2 (SAM-2) does not specify exactly which bits are assigned to the Target and which bits to the LUN, the FibreBridge makes this user definable. The default assignments are listed below.

Bit Number

15	14	13	12	11	10	9	8	7	6	5	4	3	2	1	0
0	0		N/A			Bus Identifier			Target				LUN

The location and width of the Bus, Target and LUN fields are field programmable and are stored in the FibreBridge non-volatile RAM. This allows custom address translations to be created to meet special requirements for the customer, operating system, host bus adapter or peripheral device. Another NVRAM

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