Re: Multisession DVD creation problem.

["Thomas Schmitt" <scdbackup gmx net>]

Hi,

Γιώργος Κωστόπουλος wrote:
>     1     1 Data   0          2161583    2161584         -1
>     2     2 Blank  2163632    2295103    131472       2048

This DVD+R has only one written session.
Is this the same to which you tried to let Brasero write a second session ?
(If so, then nothing seems to have happened at that burn attempt.)


> I really tried mounting, with various combinations

Well, that DVD+R is supposed to get mounted by its first and only session
and then to show the files of that first session.

Please show the mount commands which you use and possible error messages.
(Are any files missing in the mounted directory tree ?)


> Nowadays. I have to confess (using GUI utilities for this task for
> years(mostly K3b)), I don't remember a great deal of things! :-)

When you are tired of Brasero multisession experiments on DVD+R, we could
move the discussion to bug-xorriso gnu org and explore its possibilities
on the command line. :))


--------------------------------------------------------------------------
More technical dispute:

Joerg Schilling wrote:
> I recommend to use a DVD- for testing purposes. You can make it reusable if
> you call:
>        cdrecord blank=fast

This will work for DVD-RW but not for DVD-R.

The medium will not be capable of multisession afterwards, but only of
a single session (Disk-At-Once, DAO).

>         cdrecord blank=all

This will make the DVD-RW capable of multisession (write type Incremental).
The blanking run lasts as long as a write run for the complete medium.

The third possible "blank" state is called "Restricted Overwrite" and
is overwritable similar to DVD+RW and DVD-RAM. ("Restricted" means that
all write operations must be aligned to 32 KiB chunks and write full
32 KiB chunks.)
Achievable by
  dvd+rw-format -force /dev/sr0
or
  cdrskin -v dev=/dev/sr0 blank=format_overwrite
or
  xorriso -outdev /dev/sr0 -format as_needed

It can be used as read-write Linux block device by help of driver "pktcdvd"
which can be put onto a /dev/sr by program pktsetup(1).

But given my experience with Brasero and DVD+RW, the overwritable state
will not be usable for multisession by Brasero. (growisofs and xorriso
love to use it for that purpose.)


> If you like to mount older sessions from a multi session media, you need a
> special filesystem driver that is able to to this. Such a filesystem driver
> is not available on Linux.

For CD media, Linux offers mount option "session=[1...N]".
For DVD, BD, data files, or general block devices there is no "session="
but one may still use option "sbsector=[0...NNN]" which expects the block
number of the track start.

FreeBSD has mount option -s as equivalent of Linux "-o sbsector=".


> Such a number could be retrieved via "cdrecord -media-info".

Yes, or by xorriso command -toc.


> Interesting to see that Linux seems to have added the needed feature to 
> mount(1).

That must have been at least 13 years ago.
It might be as old as this comment in Linux fs/isofs/inode.c :
  "1994 Eberhard Mönkeberg - multi session handling."
Oldest mentioning i found is from 2005
  http://lkml.iu.edu/hypermail//linux/kernel/0508.1/1073.html
(This is about a bug fix in kernel 2.4.)


Have a nice day :)

Thomas