Re: Can t blank BD-RE disc?
- To: firstname.lastname@example.org
- Subject: Re: Can t blank BD-RE disc?
- From: "Thomas Schmitt" <email@example.com>
- Date: Sat, 13 Feb 2010 20:12:58 +0100
- Message-id: <firstname.lastname@example.org>
- In-reply-to: <20100213171140.GA12184@localhost.localdomain>
- References: <20100213171140.GA12184@localhost.localdomain>
> Once again, it seems xorriso is to the rescue:
I like your attitude towards xorriso, but in
this case there is a misunderstanding:
BD-RE do not get blanked like CD-RW or DVD-RW.
xorriso just tries to handle all media types
uniformly under the premise that ISO 9660
filesystems shall to be their content.
It presents BD-RE in a very similar way as BD-R
but that is an artificial emulation. The first
ISO 9660 session and the update "sessions" get
arranged on the random-access media in a
recognizable chain of mountable images.
This works with plain files or USB sticks, too.
So this is emulated:
> Media status : is written , is appendable
> Media summary: 1 session, 12075457 data blocks, 23.0g data, 25.1m free
Not much room to add more sessions, but it
would have worked.
> $ xorriso -dev /dev/sr1 -blank "deformat"
> [..about 15 seconds passes..]
> Media status : is blank
> Does such a short blanking time seem to be correct? It takes much
> longer to fully blank even a CD-RW disc, for example.
This just defaced the existing ISO 9660
filesystem PVD (a part of the equivalent of a
The 15 seconds were needed to read a few kB from
media, to replace two byte by 'X', and to write
the few kB back to media.
You will now get from:
dd if=/dev/sr1 bs=2048 skip=16 count=1 | \
od -c | \
0000000 001 C D X X 1 ...more bytes...
whereas you see in a valid ISO filesystem
0000000 001 C D 0 0 1 ...more bytes...
You may as well be brutal and bonk 64 kB of
zeros onto the start of the media:
dd if=/dev/zero of=/dev/sr1 bs=64K count=1
As you can see, you don't need a burn program
for BD-RE. They are just much too slow for normal
filesystems. The wear patterns of sequential
archivers or burn programs are more appropriate
Have a nice day :)