SSC-3: mixing 4-byte vs. 8-byte commands inherent DI issue

Elliott, Robert (Server Storage) elliott at
Mon Feb 21 15:32:00 PST 2005

* From the T10 Reflector (t10 at, posted by:
* "Elliott, Robert (Server Storage)" <elliott at>
For block devices (SBC-2) the 4-byte LBA command is terminated in such a
situation. That might also be the right approach for tapes.
"4.4 Logical blocks
If a command is received that references or attempts to access a logical
block not within the capacity of the medium, the device server
terminates the command with CHECK CONDITION status with the sense key
set to ILLEGAL REQUEST and the additional sense code set to LOGICAL
BLOCK ADDRESS OUT OF RANGE. The command may be terminated before
processing or after the device server has transferred some or all of the
Rob Elliott, elliott at 
Hewlett-Packard Industry Standard Server Storage Advanced Technology 



	From: owner-t10 at [mailto:owner-t10 at] On Behalf Of
Kevin D Butt
	Sent: Monday, February 21, 2005 4:31 PM
	To: t10 at
	Subject: SSC-3: mixing 4-byte vs. 8-byte commands inherent DI

	I believe there is an inherent Data Integrity issue when mixing
4-byte commands with 8-byte commands.  I do not think that SSC-3
addresses this. 
	As an example, if we locate to 4-byte max + n then do a Read
Position with the short form we get only n (if implementation wraps the
value) or some other incomplete LBA. 
	Would you add this topic to SSC-3 WG agenda? 
	How do we address this issue of intermixing 4-byte and 8-byte
LBA value commands in SSC-3? 
	Kevin D. Butt
	Fibre Channel & SCSI Architect, IBM Tape Firmware, 
	6TYA, 9000 S. Rita Rd., Tucson, AZ  85744
	Tie-line 321; Office: 520-799-5280, Lab: 799-5751, Fax:
799-4138, Email: kdbutt at

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