MMC-2 Opcode Notes

Ralph Weber ralphoweber at
Wed Jan 6 14:18:04 PST 1999

* From the T10 Reflector (t10 at, posted by:
* Ralph Weber <ralphoweber at>
During the MMC-2 code import to SPC-2, I also found
two opcode notes worthy of consideration.

1) The use of 23h for READ FORMAT CAPACITIES conflicts with
a vendor specific usage of opcode 23h noted in SPC and SCSI-2.

2) The use of A7h for SET READ AHEAD conflicts with MOVE
MEDIUM ATTACHED thus prohibiting the use of MMC attached
medium changers.  I suspect that the MMC-2 working group
considered this possibility and accepted the restriction
knowing that MMC-2 includes its own attached medium changer



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