Software Write Protection

keiji_katata at post.pioneer.co.jp keiji_katata at post.pioneer.co.jp
Sun Sep 5 21:36:38 PDT 1999


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



Hello all,

I'm Keiji Katata of PIONEER. I would like to ask about Software Write
Protection. DVD Forum defines Write Protection function on re-writable
media. It is able to set or cleared by device.
1: SPC has SWP bit in Mode page 0Ah. It is recorded on device memory (not
on media).
2: SSC has persistent write protect (PERSWP) bit in Mode page 10h. It is
recorded on media. But this is SSC specific page.
3: MMC2 has SWPP bit in Mode page 1Dh. This is same as SWP of SPC.
4: In Hitach proposal, Fuji defines WIF (Write Inhibit Flag) in READ/SEND
DVD Structure command format 09h. It is recorded on media. But it is very
specific command for DVD.

What is the best way for MMC device? SSC is a kind of unique media. So it
is not good idea that MMC supports Mode page 10h. I can say same thing for
READ/SEND DVD Structure command. Other MMC media than DVD, it is hard to
support READ/SEND DVD Structure command.

My proposal is adding PERSWP in Mode page 1Dh. This is very similar bit
with SSC, but one point may be different. In the case of DVD-RAM V2.0, even
if Write Protect Notch of cartridge is set to write protected state, device
can change PERSWP on media. User can't protect the ECC block from writing
that has the WIF information. In SSC, how does the device work?

PS: Sorry to use the old t10 address.

Best Regards.


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