Write Protection Model

keiji_katata at post.pioneer.co.jp keiji_katata at post.pioneer.co.jp
Tue Dec 21 18:05:02 PST 1999


* From the T10 Reflector (t10 at t10.org), posted by:
* keiji_katata at post.pioneer.co.jp
*



Hello Tokumitsu san,

I disagree with your comment. Because your definition can work only DVD-RAM
Ver.2.0. Why do DVD-RAM fellows have a tendency to ignore the generalizing?

But I must agree to the lack of description. I would like to add "If the
mounted medium does not have Write Protect functions, the corresponding
bits shall be set to zero. If ROM media is installed without cartridge,
CWP, PWP bits shall be set to zero. If DVD-RAM Ver.1.0 media is installed,
PWP bit shall be set to zero." into "8.2 Write Protect Feature and Related
Commands" section and "Read DVD Structure command, format code 0C0h"
section.
How do you think?

I have a question about combination of cartridge and ROM media. In my
proposal, even if ROM media is in the cartridge, CWP bit shall show as is.
But this is meaningless. I wonder system may be confused by CWP bit and
system may want to release the CWP of the cartridge to allow the writing on
the ROM media. So if the mounted media is not writable for the Logical Unit
originally, MSWI, CWP, PWP bits should be set to zero.
Which is better?

Best Regards.

Keiji Katata
PIONEER CORP.





to:   aiai at dsd.mei.co.jp, Keiji Katata/Pioneer
cc:   mtfuji2 at dt.wdc.com, mmc at dt.wdc.com, t10 at t10.org
Subject:  Re[2]: Write Protection Model




     Dear Katata-san,

     I am Kenji Tokumitsu of Hitachi.
     I cannot understand the commnet from Ai-san of MEI and your response
about
     the Write Protect Feature.

     So, I am sending my comment about the Write Protect Feature.

     The definition of the Write Protect Feature proposed by Pioneer looks
     strange.

     The definition is "This Feature shall indicates that the Logical Unit
can
     report the write protect status.".
     According to this definition, I think that the Current bit shall be
set to
     one when the Logical Unit can report write protect status, even if the
     Logical Unit cannot change the PWP status for mounted medium.
     But, there is a description that "the Current bit shall bet to zero if
the
     Logical Unit can not set/release the PWP status on the mounted media
     surface.", in the proposal.

     In case of DVD-RAM drive, the drive will support both 2.6GB DVD-RAM
media
     and 4.7GB DVD-RAM media. The Write Inhibit Flag is not exist on 2.6GB
DVD-
     RAM media. However, the drive can report write protect status for
2.6GB
     DVD-RAM media. So, the Current bit shall be set to one for 2.6GB
DVD-RAM
     media. But, according to the proposal of Pioneer, the Current bit
shall
     be set to zero for 2.6GB DVD-RAM media, because the PWP status of
2.6GB
     DVD-RAM media is not changeable.
     It looks strange.

     So, I think that the definition of the Write Protect Feature should be
     changed as follows.

     ----
        This Feature shall indicate that the Logical Unit is capable of
changing
        the PWP status. This Feature shall be applied to Random writable or
        Overwritable Logical Unit only.

        The READ DVD STRUCTURE Command with Format code C0h and FFh and the
SEND
        DVD STRUCTURE Command with Format Code C0h shall be supported.
     ----

     And the SPWP bit in Table 118 and the following descriptions are not
     necessary.

     ----
        The Supports PWP(SPWP) bit indicates that the Logical Unit supports
set/
        release PWP status. If SPWP bit is set to one, the SEND DVD
STRUCTURE
        Command with Format=C0h shall be supported.
     ----

     Best Regards,

     Kenji Tokumitsu



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