MediaCentre.CircumventingARccOS History

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07 June 2008, at 04:23 PM UTC by Gnome - ddrescue supercedes dd_rescue
Added lines 18-19:

Note: GNU ddrescue supercedes dd_rescue. See [[http://www.mail-archive.com/bug-ddrescue@gnu.org/msg00038.html]]
13 February 2008, at 03:54 PM UTC by Gnome - added ddrescue
Changed lines 5-6 from:
[@ dd_rescue -A -B 65536 -v /dev/dvd DVDBACKUP.iso @]
to:
[@ dd_rescue -A -B 2048 -v /dev/dvd DVDBACKUP.iso @]
Changed lines 9-13 from:
-B 65536 tells dd_rescue to skip forward a minimum of 64k when it encounters a bad sector

I guess there's a possibility that this may not work if some bad sectors are located close to real data, or if they're not 64k aligned. In this case, using a smaller value for -B should help at the cost of a slower backup.

Added: You may need to open the DVD initially with decss. Just start "mplayer dvd://1" then quit and run dd_rescue.
to:
-B 2048 tells dd_rescue to skip forward a minimum of 2k when it encounters a bad sector

Alternatively:

[@ ddrescue -n -b 2048 /dev/dvd DVDBACKUP.iso @]

2k is the DVD sector size.

Added:
You may need to open the DVD initially with decss. Just start "mplayer dvd://1" then quit and run dd_rescue.
Changed lines 11-13 from:
I guess there's a possibility that this may not work if some bad sectors are located close to real data, or if they're not 64k aligned. In this case, using a smaller value for -B should help at the cost of a slower backup.
to:
I guess there's a possibility that this may not work if some bad sectors are located close to real data, or if they're not 64k aligned. In this case, using a smaller value for -B should help at the cost of a slower backup.

Added: You may need to open the DVD initially with decss. Just start "mplayer dvd://1" then quit and run dd_rescue
.
Added lines 1-11:
[[http://en.wikipedia.org/wiki/ARccOS_Protection|ARccOS]] is a DVD copy protection mechanism which distributes bad sectors across the disc.

Can be trivially circumvented with [[http://www.garloff.de/kurt/linux/ddrescue/|dd_rescue]]:

[@ dd_rescue -A -B 65536 -v /dev/dvd DVDBACKUP.iso @]

This backs up the DVD in /dev/dvd to the file DVDBACKUP.iso
-A tells dd_rescue to zero-fill bad sectors
-B 65536 tells dd_rescue to skip forward a minimum of 64k when it encounters a bad sector

I guess there's a possibility that this may not work if some bad sectors are located close to real data, or if they're not 64k aligned. In this case, using a smaller value for -B should help at the cost of a slower backup.
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