Another issue on time stamp setting

Takaharu Ai ai.takaharu at
Tue Mar 14 05:47:26 PST 2006

* From the T10 Reflector (t10 at, posted by:
* Takaharu Ai <ai.takaharu at>
Hello MMC members,
In the last WG meeting, we decided to revise the document according to
the comment on time stamp setting function in SEND DISC STRUCTURE
command. The comment was that the time was unique in the world and the
Media Type field setting in CDB was meaningless. After some discussion,
we agreed that the Media Type field could be ignored when the Format
field was set to 0Fh, i.e. Timestamp.
Now, we Panasonic have further comment on this issue.
The new issue is that the MMC does not define the lifetime of the set
time stamp. Our concern is that very old time stamp may be recorded on
the disc, if it is not renewed every time when it is necessary to be
For example, a DVD burning software A sets the time stamp every time
when it is necessary, and a BD burning software B does never set the
time stamp. If an user burns a DVD by using A software on Monday, and
exchange the disc to BD and burns it by using B software on Saturday. In
this case, the time stamp burned on the BD disc is Monday, although it
is Saturday.
So, we propose the drive should clear the stored time stamp upon the
disc ejecting. We think this is not necessary to be the mandatory action,
but at least it should be allowed.
Best Regards,
Harry Ai
Panasonic AVC Networks Company
Osaka, Japan
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