READ DISC STRUCTURE command

[takeshi_kohda at post.pioneer.co.jp]

* From the T10 Reflector (t10 at t10.org), posted by:
* takeshi_kohda at post.pioneer.co.jp
*
Dear Ai-san,

My previous comment was not correct.
The following sentence is described in READ DISC STRUCTURE command on page
582. (Fuji6 rev0.95)

"Note: This DISC STRUCTURE is generated by the logical unit rather than
read from the medium."

And the Format Code (FFh) works regardless of existence of a medium in the
drive.
So when a medium is not mounted in the drive, the Layer Number field is
definitely meaningless as you said.
In this sense, even if a medium is mounted in the drive, the Layer Number
field of Format Code FFh may or may not work.
I would like to confirm it in the next Mt. Fuji meeting.

Best regards,
---
Takeshi Kohda




2005/10/03 15:35, takeshi_kohda at post.pioneer.co.jp wrote:
>
> Dear Harry-san,
>
> > Also, Layer Number field in CDB for FFh is meaningless.
>
> I think the Layer Number field is meaningful if the Disc Structures prese
> nt
> in each layer is different.
> For example, a DVD OTP disc does not contain Physical Format Information
> on
> Layer 1 because there is no CDZ.
> But DVD PTP disc contains it on Layer 1 because CDZ is there.
> The list of returned structure may be different between Layer 0 and Layer
> 1.
>
> The change of the "Layer Number" field to the "Reserved" field is technic
> al
> change and therefore we need confirmation among members.
>
> Best regards,
> ---
> Takeshi Kohda
>
> 2005/09/30 17:16, Takaharu Ai <ai.takaharu at jp.panasonic.com> wrote:
> >
> > Hello Mt.Fuji members and MMC members,
> >
> >
> > We find one small problem on Mt.Fuji6 Rev 0.95.
> >
> > The problem is on READ DISC STRUCTURE command with Format code=FFh.
> > The current definition is;
> >
> >     The Format Code value of C0h through FFh are used to return media
> >     independent information. Regardless of the Sub-command field value
> >     in CDB, the same information is returned to the host.
> >
> > But the following contents of the Format Code value of FFh varies
> > according to Sub-command.
> >   - DISC STRUCTURE Data Length
> >   - Format Codes applicable to the specified Sub-command
> > Also, Layer Number field in CDB for FFh is meaningless.
> >
> >
> > So, we think the definition should be;
> >
> >     The Format Code value of C0h through FEh are used to return media
> >     independent information. Regardless of the Sub-command field value
> >     in CDB, the same information is returned to the host.
> >
> >     For Format Code value of FFh, supported Format Codes for the
> >     specific Sub-command and their length shall be returned according t
> o
> >     the Subcommand field value in CDB.
> >
> > And the Layer Number field for Format Code FFh should be Reserved.
> >
> >
> > Harry Ai
> > MSDC
> > Panasonic AVC Networks Company
> > Matsushita/Panasonic
> > Osaka, Japan
> >
> >
> >
>
>


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