Hi Antonio, Thanks for your very quick reply, and your work on ddrescue and this list, of course.
> John Bokma wrote: >> rescued: 667650 kB, errsize: 4096 B, current rate: 0 B/s >> ipos: 667652 kB, errors: 1, average rate: 565 kB/s >> opos: 667652 kB, run time: 1.88 m, successful read: 52 s >> ago >> >> Based on what I've read those are most likely 2 blocks created by >> Track-At-Once: "two unreadable run-out blocks at the end of the track." > > I think so. > > >> Based on the above I calculate the size of the ISO image as: 32581 x >> 2048 = 667342848 It gets weirder, I go through my CDs in chronological order and now am at CDs written using "Nero". The calculated size seems to include the two unreadable run-out blocks since of the 4 or so CDs checked all have 2 unreadable blocks at the very end (4096B errsize). I have to check if this is actually the 150 'nulled' blocks + 2 unreadable ones. >> The rescued image, however, is 667650048 bytes; 307200 bytes larger, or >> 150 blocks. Is this also a side effect of Track At Once? >> >> Should I use the --size option (on both) to just grab the blocks as >> reported by isoinfo? > > I am no CD expert, but I remember to have read about some "150 lead-in > sectors". The CDs I ripped, so far seem to have those 150 sectors at the end, but: > If I were to store the iso images, I would store them complete > just in case I cut the wrong 150 sectors out of them. Yes, I am now convinced that this is /the best advice/. What I am going to do: rip each CD (the ones done, again) and if the last 2 blocks are unreadable: - check if the last 150 sectors are all null and (if not too much coding work) always check that the /last/ file falls entirely within the ripped image. And not worry too much about null sectors, etc. The images are not going to be burnt back to CD anyway. I want to store ~ 6 images with PAR2 (or similar) on DVDs and on a backup disk for archival purposes. It's quite a surprise that most CDs, ~14 years old read without a single problem. And the CDs that cause problems are mostly made by Sony (at first I joked "Only Sony", but I found a non-Sony one). I can actually see big holes (few mm) in the top layer. But no worries, because I have the damaged files on several working CDs. Thanks again, John _______________________________________________ Bug-ddrescue mailing list [email protected] https://lists.gnu.org/mailman/listinfo/bug-ddrescue
