Clarification on 8 byte single level LUN format in SPI-4

Spalding, AlanC Alan_Spalding at adaptec.com
Tue Aug 27 11:28:33 PDT 2002


* From the T10 Reflector (t10 at t10.org), posted by:
* "Spalding, AlanC" <Alan_Spalding at adaptec.com>
*
Hi Guy,
My understanding is byte 1 in the SAM-2 LUN field is byte 5 in the L_Q IU.


George Penokie kindly confirmed this a number of months ago:

>>>begin snip
Alan,
Yes byte 1 in the LUN field is byte 5 in the L_Q IU.

Bye for now,
George Penokie

My question:
Also, one last question, this single level LUN field is defined as Byte 1
of the LUN structure in SAM-2, this would be Byte 5 of the SPI L_Q IU in
SPI-4, correct? (Logical Unit Number starts at Byte 4).
>>> end snip


Cheers
alan


-----Original Message-----
From: Kendall, Guy [mailto:gkendall at lsil.com]
Sent: Tuesday, August 27, 2002 10:09 AM
To: 't10 at t10.org'
Cc: Perucca, Nick
Subject: Clarification on 8 byte single level LUN format in SPI-4


* From the T10 Reflector (t10 at t10.org), posted by:
* "Kendall, Guy" <gkendall at lsil.com>
*
The SPI-4 L_Q contains an 8 byte LUN field where the MSB is sent first, and
the LSB sent last. SPI-4 references SAM-2 for the format of the 8 bytes. In
SAM-2 rev. 23, section 4.8, table 1 shows the format of the Single Level LUN
structure. Byte one shall contain the 8-bit LUN, and all other bytes shall
be zero.

I am looking for 100% clarification on which bytes in the SPI-4 table match
up with the SAM-2 table. I thought I understood this, but now it is in
question and I'm looking for clarification.

My question is, in the SPI-4 L_Q, does the MSB correspond to byte zero in
the Single Level LUN format in SAM-2, or to byte 7? Since the actual 8-bit
LUN is in byte one of the single level LUN structure, will this LUN byte be
sent out second or seventh of the 8 bytes?

Thanks,
Guy Kendall

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