A Request to MMC WG from BDA

keiji_katata at post.pioneer.co.jp keiji_katata at post.pioneer.co.jp
Tue Jan 6 23:11:59 PST 2009


* From the T10 Reflector (t10 at t10.org), posted by:
* keiji_katata at post.pioneer.co.jp
*
Dear Bill,
BDA has a request to MMC6.
For Current/Maximum Capacity Descriptor of the READ FORMAT CAPACITIES command
there are two implementations on BD-R drive with a Blank BD-R disc. The 1st
implementation reports Data Area size as Spare Area included that is
specified
by BD-R specification. The reported value includes Inner Spare Area that host
never be able to Read/Write. The 2nd implementation reports User Data Area
size
that does not include the Inner Spare Area.
MMC5-BSR+INCITES=430.pdf on page 471
Table 468 ? Current/Maximum Capacity Descriptor for Unformatted or Blank
Media
BD-R: The number of sectors in all the data zones on the media.
MMC5 used a term "data zone" for two meanings. The 1st meaning is Data Zone
of
BD-RE/R that includes user data recordable area and spare area. The 2nd
meaning
is user data recordable area. These two usages allow these different
implementations of BD-R drives.
On the other hand MMC3/MMC4 specifies generic definition of Current/Maximum
Capacity Descriptor of the READ FORMAT CAPACITIES command as follows;
mmc3r10g.pdf Table 210 on page 201
01b Unformatted Media.
The reported value is for the maximum formatted capacity for this media. For
DDCD/CD-RW medium, the value reported is the maximum possible when using
Format
Type 10h.
mmc4r05a.pdf Table 416 on page 347
01b Unformatted Media.
The reported value is for the maximum formatted capacity for this media.
These two descriptions said that the original intention of this field
requests
to show the possible maximum recordable / readable capacity of a disc.
Fortunately Data Zone of CD/DVD does not include Spare Area. Then capacity of
all Data Zones of CD/DVD disc follows the original intention.
BDA concluded that two different implementations do not cause any trouble and
both implementations are reasonable. Therefore BDA would like to request to
MMC
WG that MMC6 may have a note that explains these two implementations of the
BD-R
writable drives as follows.
Note: There are two implementations for BD-R writable drive. One
implementation
reports a value that includes Inner Spare Area. Another implementation
reports a
value of the maximum user data recordable area. Host may use the third
descriptor values of Format Type 32h or READ TRACK INFORMATION Command
response
to obtain a maximum recordable capacity of the Blank BD-R disc.
I personally think that MMC6 may have same table with Table 210 of MMC3 to
explain this original intention and then explain each medium definitions.
Best regards,
Keiji Katata
PIONEER CORP.
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