On Friday 17 March 2006 23:13, Joseph <[EMAIL PROTECTED]> wrote about 'Re: [gentoo-user] dd if=/dev/dvd of=backup.iso': > program k9copy didn't work for me and k3b stopped after copying 850Mb > dmesg showing a lot of errors: > hdc: media error (bad sector) status=0x51 SeekComplete Error > hdc: media error (bad sector) status=0x34 > > It could be that few disks had an error but I get similar error reading > commercial disk as well. So much for DVD enjoyment (very unreliable).
I get errors on commercial disks as well. Some are for copy protection. Some are just bad sectors than, when playing, the player skips. (2k is less than a frame; one bad sector doesn't even cause a skip most of the time.) I turn on 128 retrys, and ignore read errors for after that. I've never had trouble playing an iso ripped that way. DVDs absolutely SUCK as a backup solution. The data density is just too high for the media. If you want to back up more than 10G use tape (if you can ensure a clean environment) or USB/iSCSI/eATA/nfs attached storage. For pure, unadulterated, bit-by-bit copies, I can only suggest the tool(s) mentioned earlier in the thread that let you read multiple times, either from a single drive of multiple different drives (better), and combine them into a single .iso. Even dd w/ conv=noerror will give up after some point and write some data that may (or may not) be correct for that sector. -- "If there's one thing we've established over the years, it's that the vast majority of our users don't have the slightest clue what's best for them in terms of package stability." -- Gentoo Developer Ciaran McCreesh -- gentoo-user@gentoo.org mailing list
