Comments to MMC4 from CDs21 TWG3

Masaetsu Takahashi tak at shinyoko.ricoh.co.jp
Thu Feb 27 00:07:11 PST 2003


* From the T10 Reflector (t10 at t10.org), posted by:
* Masaetsu Takahashi <tak at shinyoko.ricoh.co.jp>
*
Dear all,

I would like to raise comments to the latest MMC4 draft (Rev. 1f) on 
behalf of CDs21 Solutions TWG3 (CD-R/RW industry group in Japan).
TWG3 has been studying how drive should treat unsupported media, for 
example, High Speed or Ultra Speed CD-RW media inserted into drives 
which do not support recording to those media. We have agreed to send 
the following comments to MMC group and would like to have them included 
in the next draft. Basic idea follows the MMC3 specs, but some 
clarifications and suggestions to error codes for related commands are 
proposed.

We appreciate your reviewing the comments and would like to discuss at 
the next MMC4 meeting.

Regards,
Masaetsu Takahashi

---------------------------------

Media recognition and Recording speed setting

(1) Recommendations to how to recognize media and how to set recording 
speed in general
1. Host should detect the media type by reading groove information
2. Host should detect the writing capabillity for inserted media
3. Host should set the write speed according to results of the step 1/2

(2) Recommendations to CD-RW case
1. Detect the media sub-type
Host should issue READ TOC/PMA/ATIP (Format=4) command.
Drive should response with appropriate ATIP information.
Host should interpret ATIP information and aquire the media sub-type.

2. Detect the writing capability of the drive
Host should issue GET CONFIGURATION command.
Drive should report;
    000Ah:    CD-RW Profile

If the inserted media is supported by drive, the following feature 
should be current (for example);

    0021h:    Incremental Streaming Writable Feature
    0023h:    Formattable Feature
    0026h:    Restricted Overwrite Feature
    002Dh:    CD Track at Once Feature
    002Eh:    CD Mastering Feature

Also, the supported media sub-type should be reported by;
    0037h:    CD-RW Media Write Support Feature

If the inserted media is not supported by drive, the following feature 
shall not be current;

    0021h:    Incremental Streaming Writable Feature
    0023h:    Formattable Feature
    0026h:    Restricted Overwrite Feature
    002Dh:    CD Track at Once Feature
    002Eh:    CD Mastering Feature

However, CD-RW Media Write Support Feature (0037h) should be reported so 
that host can know which media sub-type is supported by drive.
Host should report to user the reason why the inserted media could not 
be written ("unsupported media sub-type").

3. Set the write speed
If the steps 2 succeeded, then;
Host should issue GET PERFORMANCE command to get a list of possible 
write speed descriptors.
Drive should report the list of available speeds.
Host should set the appropriate writing speed according to the responses 
to GET PERFORMANCE, GET CONFIGRATION and READ TOC/PMA/ATIP commands.
Host should issue SET STREAMING command with appropiate speed.

(3) CD-RW legacy procedure (informative):
1. Detect the media sub-type
Host should issue READ TOC/PMA/ATIP (Format=4) command.
Drive should response with appropriate ATIP information.
Host should interpret ATIP information and aquire the media sub-type.

2. Detect the writing capability of the drive
Host should get writing capability of the drive through CD/DVD 
Capabilities and Mechanical Status Page (Page Code 2Ah).

3. Set the write speed
Host should get the list of available speeds through CD/DVD Capabilities 
and Mechanical Status Page (Page Code 2Ah).
Host should set the appropriate writing speed according to the responses 
to READ TOC/PMA/ATIP command.
Host should issue SET CD SPEED command with appropriate speed.

(4) Error reporting
4-1. TEST UNIT, READ TOC/PMA/ATIP, READ DISC INFORMATION and READ TRACK 
INFORMATION commands
These commands should work regardless of media sub-type even if the 
media is not supported by drive.

4-2. WRITE command
If the drive receive WRITE command to unsupported media sub-type, the 
drive should return error;
    5 30 05 CANNOT WRITE MEDIUM - INCOMPATIBLE FORMAT

4-3. READ command
If the drive receive READ command to unsupported blank media sub-type, 
drive should return error with "blank check 08/00/00" or "Illegal Mode 
for this Track 05/64/06".




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