MMC-4/6 Reference in SBC-2/3/4

Paul Suhler Paul.Suhler at
Wed Sep 10 13:07:16 PDT 2014

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At this week's CAP meeting, we realized that the following command CDBs each
have a bit marked as "Restricted for MMC-6."  However, *none* of these
commands appear in MMC-6.  These bits are restricted as far back as SBC-2,
where they are restricted for MMC-4:
READ(16) byte 14 bit 7
VERIFY(12) byte 10 bit 7
VERIFY(16) byte 14 bit 7
WRITE(16) byte 14 bit 7
WRITE AND VERIFY(12) byte 10 bit 7
WRITE AND VERIFY(16) byte 14 bit 7
There are three SBC commands with a bit restricted for MMC-4/6 that *do*
appear in MMC-4/6:  READ(12), VERIFY(10), and WRITE(12).
I am working on a proposal for which I would like to use that bit in the
READ(16) and WRITE(16) commands.  I suspect that in SBC-2 the bit was moved
into the six commands under the incorrect assumption that they would be used
in MMC-4, and they were simply carried forward in SBC-3 and -4 without being
If anyone knows why this bit was marked restricted a decade ago, then please
let me know.
Paul A. Suhler, PhD
Research Staff Member
HGST Research
paul.suhler at
o: 949-476-1180 x275448
m: 949-241-6443
3001 Daimler St.
Santa Ana, CA 92705-5812<<a href="">;

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