Fixed sense data valid bit and MMC-5

David Burg dburg at nero.com
Tue Feb 22 10:31:55 PST 2005


* From the T10 Reflector (t10 at t10.org), posted by:
* "David Burg" <dburg at nero.com>
*
Hello Doug,

Thanks for sharing this with us.

I think MMC5 should request the MMC devices to set the valid bit correctly.
My own software for instance trust this bit and will not work with devices
forgetting to set it.

Best regards,

David Burg

----------------------------------------------------------------
David Burg
Software Development,
InCD and Low Level Drivers Project Leader

Nero AG               phone: +49 (0)7248 911 862 (room line) Internal VoIP
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Im Stoeckmaedle 18    fax:   +49 (0)7248 928 299
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-----Original Message-----
From: owner-t10 at t10.org [mailto:owner-t10 at t10.org] On Behalf Of Douglas
Gilbert
Sent: Sunday, February 20, 2005 12:16 AM
To: t10 at t10.org
Subject: Fixed sense data valid bit and MMC-5

* From the T10 Reflector (t10 at t10.org), posted by:
* Douglas Gilbert <dougg at torque.net>
*
SPC-3 rev 21d states in section 4.5.3 on fixed format sense
data: "A VALID bit set to zero indicates that the INFORMATION
field is not defined in this standard or any other command
standard (see 3.1.18). A VALID bit set to one indicates the
INFORMATION field contains valid information as defined in
this standard or a command standard."

SBC-2 complies with this and disks that I test do indeed
set the VALID bit when they report a MEDIUM ERROR. However
I am seeing a CD/DVD combo drive report a MEDIUM ERROR
with an INFORMATION field set to a very likely lba but
the VALID bit is clear. Further, when I look at MMC-5 it
discusses reporting MEDIUM ERRORs and setting the INFORMATION
field but no mention of the VALID bit.

If the CD/DVD drive I am testing reflects common practice
(i.e. following MMC) then perhaps the statement in SPC-3
needs to be weakened or a note added. Perhaps MMC-5 could
make a statement about the VALID bit as well.

Doug Gilbert


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