Inconsistency between MMC-4, MMC-5, and MMC-6 on READ (12) opcode

Ralph Weber Ralph.Weber at wdc.com
Mon Mar 3 17:16:01 PST 2014


* From the T10 Reflector (t10 at t10.org), posted by:
* Ralph Weber <Ralph.Weber at wdc.com>
*
As described below, MMC-4 is violating an operation code requirement that has
been documented since SCSI-2 (see 7.2.1 in SCSI-2 r10L).
o Operation codes 2xh and 3xh are in operation code group 1 (i.e., 10 byte
CDBs).
o Group 5 is the correct choice for a 12 byte CDB (i.e., operation codes Axh
and Bxh).
I would further note that the READ(12) operation code in SBC is A8h, and the
the numeric operation codes list in SPC cites MMC-6 as having an optional
READ(12) command defined with operation code A8h.
It appears to me that MMC-4 had in incorrect operation code definition for
READ(12), which was corrected in MMC-5.
All the best,
.Ralph
________________________________________
From: owner-t10 at t10.org [owner-t10 at t10.org] on behalf of John Lohmeyer
[lohmeyer at t10.org]
Sent: Monday, March 03, 2014 5:52 PM
To: T10 Reflector
Subject: Inconsistency between MMC-4, MMC-5, and MMC-6 on READ (12)  opcode
* From the T10 Reflector (t10 at t10.org), posted by:
* John Lohmeyer <lohmeyer at t10.org>
*
I have added an agenda item to the CAP working group to consider what should
be done about an inconsistency between the READ (12) operation code in:
  Standard READ (12)
	   opcode
  MMC-4    28h
  MMC-5    A8h
  MMC-6    A8h
I would welcome opinions on how we should address this issue. Z JAN from
China says MMC-4 is correct and the other standards are in error.
John
--
John Lohmeyer		       Email: lohmeyer at t10.org
LSI Corp.		       Voice: +1-719-533-7560
4420 ArrowsWest Dr.		Cell: +1-719-338-1642
Colo Spgs, CO 80907
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