Re: [Bug-ddrescue] Reference to dvdisaster in manual

[Gadgetmind]

On 2017-11-20 15:29, address@hidden wrote:
> dvdisaster can only recover discs that generated ECC data for and not
> generic disks with read errors?!

That is also my reading.

A few years ago, I created a tool that used what's called a "CatWeasel" 
card in a PC to read raw MFM sectors off some damaged floppies, recover 
what it could of data (ignoring if required damaged sector headers), and 
then create an output file of what it had got along with "goodness" 
flags. I could then do multiple runs with different drivers and settings 
and merge the results of a few passes.

This didn't get all the data so I wrote a new tool that used the quality 
of the MFM interleaved clock bits to suggest which areas where bad and I 
could then use bad raw sectors from multiple runs, and if required brute 
force, to try and get a good CRC32.

I ended up getting every scrap of data off 15+ floppies that had been in 
my loft for 30 years but it did take three months of part-time coding!

A tool *could* use similar techniques for DVDs and perhaps merge good 
data after C2 from multiple runs to try and get good data to feed into 
C3 but dvdisaster doesn't seem to do this, so the good results story 
seems to be more good luck.