Comment 94 for bug 780117

Hi,

some technical comments to Nico Zanferrari's notes:

> (I always use a fresh standard live 32 bit USB key with the same DVD-RW)
> [...]
> - the "unreadable coasters" produced from other Ubuntu versions are seen as
> blank disk from standard brasero 12.10, and can be easily blanked with it.
> This is different from old versions of brasero that does not recognise it at
> all as a DVD medium.

If the DVD-RW was recorded with write type DAO and suffered the
found bug, then it might afterwards bear an unclosed session,
because the pre-announced amount of data was not sent to the
drive.
libburn qualifies such a medium as "unsuitable" but also offers
the opportunity to make it pretend being closed, so that it can
be blanked. (Current Brasero git does not bear the necessary
call burn_disc_pretend_full(), though.)

So it is not sure that this problem is caused by the bug of
october 2010.
Backporting the fix would be helpful to clarify this.

> - the bug (don't ask me why) is quite different on 12.10. Here sometimes you
> can have a readable DVD, but never on the first recording! It seems that
> it's somehow and sometimes able to record a second recording session on what
> it thinks it's a blank disk.

Theoretically two half sessions of the same size could fill
the pre-announced size of the DAO session. But it is hardly possible
that the result bears proper directories or file content.
The first block of each pair of 2 KB blocks was not written.
Any directory, that occupies more than one block, would become
damaged. Any data file that has more than one block would not
match its original on disk.

Again, backporting the fix and testing the effect would bring
more insight.

If it turns out that there was another bug which is gone in the
current git version of Brasero, then it would be worthwhile to
identify the changeset which solved that problem.

Have a nice day :)

Thomas