Re: Writing Dual Layer DVD-RW using Linux
Hi,
me:
> > Unformatted DVD-RW need to be blanked before re-usal:
> > dvd+rw-format -blank=full /dev/hdc
Joerg Schilling:
> This is nonsense!
> Unformatted DVD-RW media may be used without special preparations.
Unused unformatted media: yes.
But my statement was about re-usal after previous
use for writing.
Unformatted DVD-RW written by growisofs or by
cdrskin may be left appendable or may be closed.
cdrecord always closes them.
cdrecord will not write to closed or to appendable
DVD-RW. (At least it did not when i tried it in
January 2007 with the then current version.)
But it will blank them and then be ready to re-use.
Joerg:
> Formatting puts them into the one of two possible packet writing modes.
> This specific mode: random accessible packet writing is typically
> les reliable.
It changes media profile from 14h to 13h and enables
feature 2Ch "Rigid Restricted Overwrite", where the
rigid restriction is that both write address and
write amount have to be aligned to 32 KiB. Such a drive
is allowed to _not_ implement read-modify-write emulation
of non-aligned data. (MMC-5, 5.3.22)
As profile 14h a DVD-RW can either write DAO (with pre-announced
size) or Incremental Streaming (with open-end size).
Both write types work only sequentially and not as random
access. Inremental Streaming allows to keep the media
appendable and to write further sessions to it.
Afaik, cdrecord only supports DAO currently.
growisofs supports both write types of profile 14h
and the write type of profile 13h. So does cdrskin.
me:
> > growisofs promises to do BD-RE.
Joerg:
> cdrecord does too!
Does it allow piping of a compressed (s)tar archive
on-the-fly ? With no size prediction ?
I could not test that with growisofs and BD-RE.
But if it is possible with the media at all (and
they look like that in the specs), then i expect
that growisofs will allow this piping.
Actually the features of profile 43h BD-RE make
hope that it is well suited to be supported as
block device by the operating system.
Just like with DVD-RAM.
Have a nice day :)
Thomas
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