Re: DVD-R as backup medium: growisofs + udftools
Hi,
Joerg Schilling:
> > It is _impossible_ to do correct backups without additional disk space.
Giuseppe Corbelli:
> You say it is necessary to store star archives on a filesystem prior
> to backup?
It is possible to write archives as sessions
directly to multi-session media: DVD-R, DVD+R,
DVD-RW, CD-R, CD-RW.
As long as one knows the start addresses it
is easy to read the archives by help of dd.
This works for afio as well as for star.
Try for example:
find . | \
afio -oZ - | \
cdrskin -v dev=/dev/sr0 -multi -
The writer drive should be able to tell a
table of content:
cdrskin -v dev=/dev/sr0 -toc
With a 4 session DVD+R it should report
something like:
...
cdrskin: status 3 BURN_DISC_APPENDABLE "There is an incomplete disc in the drive"
...
Current: DVD+R
...
first: 1 last 4
track: 1 lba: 0 ( 0) 00:02:00 adr: 1 control: 4 mode: 1
track: 2 lba: 66112 ( 264448) 14:43:37 adr: 1 control: 4 mode: 1
track: 3 lba: 87744 ( 350976) 19:31:69 adr: 1 control: 4 mode: 1
track: 4 lba: 1663056 ( 6652224) 369:36:06 adr: 1 control: 4 mode: 1
track:lout lba: 1682640 ( 6730560) 373:57:15 adr: 1 control: 4 mode: -1
The lba values 0, 66112, 87744, 1663056 tell the
start addresses in 2048 byte blocks.
Like:
lba=66112
dd if=/dev/sr0 bs=2048 skip=$lba | afio -tv -
One problem is that my DVD-ROM drive does not tell
about all DVD tracks but at most issues a fake table
of content with an initial pseudo-session and the
last session.
So one should memorize the start addresses after burning.
Have a nice day :)
Thomas
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