Re: xorriso -close off doesn't work?

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

Hi,

i sent this reply yesterday ongly to Zhang Weiwu by mistake.
So now for the list:

> $ xorriso -dev /dev/sr0 -blank as_needed -close off -as mkisofs
> -exclude-list .exclude.lst .
> ...
> almustafa@jamaica:~$ dvd+rw-mediainfo /dev/sr0
> ...
>  Mounted Media:         1Ah, DVD+RW
> ...
>  Disc status:           complete
>  Number of Sessions:    1
>  State of Last Session: complete
>  Number of Tracks:      1
>  BG Format Status:      complete
> ...
>  formatted:  2295104*2048=4700372992
>  26h(0):    2295104*2048=4700372992
> ...
> READ CAPACITY:          2295104*2048=4700372992
> 
> It seem to suggest the media is closed. 

A DVD+RW cannot be closed on media level. It always bears a single
formatted track which can grow with further writes but never shrinks.

The media listed is fully formatted up to maximum capacity.
Formatting happens automatically in background while writing. If the
written area comes near the end of the media then formatting gets
completed. 
dvd+rw-mediainfo will not tell you the size of the ISO image.
It is entirely focused on the MMC aspects of the media.

If you run 
  xorriso -outdev /dev/sr0 -toc
then you should get reported something like
  ...
  Media current: DVD+RW
  Media product: MKM/A02/48 , Mitsubishi Kagaku Media Co.
  Media status : is written , is appendable
  TOC layout   : Idx ,  sbsector ,       Size , Volume Id
  ISO session  :   1 ,         0 ,    597722s , ISOIMAGE
  Media summary: 1 session, 597722 data blocks, 1167m data, 3315m free
  Media nwa    : 597728s


xorriso's DVD+RW multi-session emulation is the same on DVD+RW, DVD-RAM,
BD-RE, data files on disk, or USB sticks. It differs from the real
multi-session writing as described by MMC for CD, DVD-R, DVD+R, and BD-R.
Nevertheless it has the same effect on the mountable images.

xorriso is considering DVD+RW as closed if their first 64 kB are not
all zero but also are not the beginning of an ISO-9660 filesystem.

xorriso -blank as_needed overwrites the first 64 kB by either all zeros
if it was no ISO 9660, or it devalues the ISO 9660 filesystem by a small
change that defaces the Primary Volume Descriptor. (This defacing can be
revoked by writing back the PVD Standard Identifier text "CD001" into
bytes 32769 to 32773 of the ISO image.)
These content states are considered "blank" and xorriso will overwrite
them by a new ISO image.

If a valid ISO image exists, then the media is considered "appendable"
and xorriso will add sessions to it rather than overwriting it from
scratch.


Have a nice day :)

Thomas