Hello Kay,
For some reason, the mailing list ate your message twice. I quote it below.
Kay Diederichs wrote:
Dear Antonio,
I have been trying to recover, using ddrescue 1.21-rc2, data from a CD
burnt in 2002. After trying 6 different CD drives, I got 99.9% of data
back, but ended up with 32 remaining errors (65536 lost bytes, affecting
several files). This was using the -d -r3 -b2048 options, and the
process took several hours. In the last hours there was little reduction
of errors so I thought that the affected files were lost.
However, I could quickly and painlessly recover this same CD after
trying (in dispair) the dvdisaster 0.79.5 tool, by enabling the "Read
and analyze raw sectors" under "Preferences"/"Read attempts". The
visualization that dvdisaster provides showed up to a few hundred
recovered C2 errors in the damaged range of the CD, but not even the
read speed decreased much. I have now all my files back.
So, do you think it would be possible to enable, in ddrescue, the
correction of C2 errors if the drive supports it? Or is there a
workaround using, say, hdparm to issue a ATA-passthrough command or the
like?
My CD drive is a "HL-DT-ST DVDRAM GH22NS50", and I don't think this is a
special nor expensive drive.
thank you,
Kay
First of all, I am glad that you recovered all your files. :-)
I think that there is no need to add correction of C2 errors to ddrescue
because there is already a specialized free tool that corrects them;
dvdisaster.
I think the best thing I can do is to document in the manual that
dvdisaster may be a better option than ddrescue for recovering data from
CDs because dvdisaster can read and analyze raw CD sectors, which
ddrescue can't.
Best regards,
Antonio.
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