[mythtv-users] DVD ISO playback problems: Invalid IFO

Seth Daniel mythtv.org at sethdaniel.org
Thu Jan 10 01:01:36 UTC 2008

On Wed, Jan 09, 2008 at 07:40:44PM -0500, Michael T. Dean wrote:
> On 01/09/2008 07:21 PM, Seth Daniel wrote:
> > On Wed, Jan 09, 2008 at 07:14:00PM -0500, Michael T. Dean wrote:
> > [...snip...]
> >   
> >> /me wonders why distros still use dd_rescue instead of ddrescue (and, if 
> >> installing dd_rescue, why they don't install dd_rhelp).
> > Well, Ubuntu (I'm running Hardy) has a package named 'ddrescue' which
> > installs a program named 'dd_rescue'.  It would appear that the binary
> > is the Garloff version.  
> >
> > $ dd_rescue
> > dd_rescue: (fatal): both input and output have to be specified!
> >
> > dd_rescue Version 1.13, garloff at suse.de, GNU GPL
> > ($Id: dd_rescue.c,v 1.55 2007/03/18 14:29:10 garloff Exp $)
> > dd_rescue copies data from one file (or block device) to another.
> > [...snip...]
> >   
> Yep.  Perhaps the MythBuntu guys would have some insight into why Ubuntu 
> uses dd_rescue (or enough pull to recommend a change--either including 
> dd_rhelp or, better, using ddrescue).

I just noticed this:

$ apt-cache -f search gddrescue
Description: the GNU data recovery tool
 it copies data from one file or block device (hard disc, cdrom, etc)
 to another, trying hard to rescue data in case of read errors.
 gddrescue does not truncate the output file if not asked to.
 So, every time you run it on the same output file,
 it tries to fill in the gaps.
 The basic operation of ddrescue is fully automatic.
 That is, you don't have to wait for an error, stop the program,
 read the log, run it in reverse mode, etc.
 If you use the logfile feature of ddrescue, the data is rescued
 very efficiently (only the needed blocks are read).
 Also you can interrupt the rescue at any time and resume it later
 at the same point.
 Automatic merging of backups: If you have two or more damaged
 copies of a file, cdrom, etc, and run ddrescue on all of them,
 one at a time, with the same output file, you will probably obtain
 a complete and error-free file. This is so because the probability
 of having damaged areas at the same places on different input files
 is very low. Using the logfile, only the needed blocks are read from
 the second and successive copies.
 The logfile is periodically saved to disc. So in case of a crash you
 can resume the rescue with little recopying. Also, the same logfile
 can be used for multiple commands that copy different areas of the
 file, and for multiple recovery attempts over different subsets.
 gddrescue aligns its I/O buffer to the sector size so that it can be
 used to read from raw devices. For efficiency reasons, also aligns it
 to the memory page size if page size is a multiple of sector size.

This seems like what you are talking about.

Up until today I had simply assumed it was a graphical frontend to 
dd_rescue.  :o) 

seth /\ sethdaniel.org

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