Re: dvd+rw burner

["Thomas Schmitt" <scdbackup@gmx.net>]

Hi,

Gene heskett wrote:
> on that same staples dvd+rw disk:
> xorriso -as cdrecord -v dev="$drive" fs=16m -eject "$image" 2>&1 | tee -i /tmp/xorriso.log
> apparently xorriso, which I had to install, completed normally but did take
> a long time closing, I'll send the log by PM

Summarizing the burn run:
The medium was not yet completely formatted.
The drive became ready for writing after 25 seconds of formatting.
The image was just 6 MB small and written within 7 seconds.
Then it lasted 144 seconds until the drive indicated that it was ready
for more activity.

I did not get this long waiting time on a fully formatted DVD+RW. But a
new one in an ASUS BW-16D1HT drive needed 86 seconds from end of writing
until the background formatting ended and the medium state could be
inquired by xorriso.
When i look at the writeable side of the DVD i see a narrow dull ring
surrounded by a broad shiny ring. So most of the DVD is still unformatted
and waits for a burn run with more data.

At the end of the xorriso run, the medium status was "closed".
With overwritable media this assessment of xorriso is an emulation of
the content state. "closed" means that there were non-zero data readable
in block 16 of the medium which do not look like an ISO 9660 filesystem
superblock. (xorriso has a strong tendency towards ISO 9660.)


> however, if the disk is re-inserted and:
> gene@coyote:~/AppImages$ xorriso -outdev /dev/sr1
> ...
> Media current: DVD+RW
> Media status : is blank
> Something definitely aglay with that disk. See line 190 of the log.

The log states:

  Media status : is written , is closed

That's not a good sign. This time there was no non-zero data readable from
block 16. This usually means that the read quality of the written medium
is very poor.

The dye of aged DVD+RW can sometimes be revived by exercises.
You could give the disk a few full burns with all zeros:

  dd if=/dev/zero bs=2048 count=2295104 | \
  xorriso -as cdrecord -v -nopad dev=/dev/sr1 -eject -

The last "-" means to read the image data from standard input into
which dd pours nearly 4483 MiB of data.
Option -nopad prevents adding of padding data which would not fit on the
DVD after dd sent the full capacity of 2295104 blocks.
The run is supposed to last about 15 minutes with 4x DVD+RW or 25 minutes
with 2.4x DVD+RW.

If such a run is successful, then the medium  be classified by xorriso
as "blank".
After a successful run with non-zero non-ISO 9660 data it will be
"closed".
After a successful run with an ISO 9660 filesystem image, e.g.
a debian*.iso, it will be "appendable".


Have a nice day :)

Thomas