Re: Problems mounting DVD-RWs written with growisofs

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

Hi,

I see Andy showed up. He knows best what growisofs
does. :)

But my mail was already written when i noticed.
So anyway:

Marcus Roeckrath wrote:

> cdrecord dev=1,2,0 opensource_dvd70.iso
> and the DVD-RW was burned well, could be mounted and all data could be read 
> without any error.
> Why does the media contains correct size information after burning with 
> cdrecord but is unusable when burned with growisofs?

That was DAO recording while growisofs most probably
either used Incremental Streaming or Restricted Overwrite.


> But I uses a server based burning backend on my eisfair server 
> (webcdwriter/CDWserver) which depens on growisofs.

growisofs uses DAO on blank DVD-RW with option -dvd-compat

  growisofs -dvd-compat -Z ...

Blank profile 0014h can be achieved by

  dvd+rw-format -blank /dev/...

or
  cdrecord dev=/dev/... blank=fast

As Joerg stated, the fast-blanked media are not
suitable for the other recording mode which
allows multiple sessions on one media.
But for DAO they are ok.

DAO needs to know the data amount in advance.
growisofs can obtain this number if the image is
ISO 9660 or if the data come from a disk file.
It cannot do DAO with non-ISO-9660 from stdin.


So you have three options with DVD-RW:

- Blank media written in DAO mode.
  Option -dvd-compat or blanked with -blank=fast.

- Blank or appendable media written in
  Incremental Streaming mode.
  No option -dvd-compat and media blanked by
    dvd+rw-format -blank=full /dev/...

- Formatted DVD-RW. They do not get blanked but
  for once formatted by
     dvd+rw-format -force /dev/...
  From then on they can be overwritten. growisofs
  will warn of an eventual valid ISO image on media
  before overwriting it. If it refuses, use the
  secret weapon: option -use-the-force-luke


I tested DVD-RW with all those modes and by own
software. None of them could really convince me
to buy any further 4x DVD-RW.
On my hardware cdrecord had no better results than
others. It just failed at other days. So for short
time one could get such an impression.

But if DAO works for your hardware, then go for
growisofs -dvd-compat resp. for fast blanked media.
(If the service in question provides the data with
predictable size, that is.)


Have a nice day :)

Thomas