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Re: dd: error reading '/dev/sr0': Input/output error




On Mon, 10 Dec 2018, Thomas Schmitt wrote:

> Date: Mon, 10 Dec 2018 02:45:43
> From: Thomas Schmitt <scdbackup@xxxxxxx>
> To: debian-user@xxxxxxxxxxxxxxxx
> Cc: mickydean@xxxxxxxxxxxxxx
> Subject: Re: dd: error reading '/dev/sr0': Input/output error
> Resent-Date: Mon, 10 Dec 2018 07:46:23 +0000 (UTC)
> Resent-From: debian-user@xxxxxxxxxxxxxxxx
>
> Hi,
>
> md wrote:
> > When copying a dvd to file on the harddrive, I'm getting [...]
> > MD> sudo dd if=/dev/sr0 of=/sdb1/movie.iso
> > 32596480 bytes (33 MB, 31 MiB) copied, 7.00018 s, 4.7 MB/s
> > dd: error reading '/dev/sr0': Input/output error
>
> Do you see fresh messages in the output of dmesg ?
> Like
>
>   Dec  2 13:56:33 ... kernel: [...] Sense Key : Medium Error [current]
>   Dec  2 13:56:33 ... kernel: [...] Info fld=0x69c0
>   Dec  2 13:56:33 ... kernel: [...] sr 2:0:0:0: [sr0]
>   Dec  2 13:56:33 ... kernel: [...] Add. Sense: Unrecovered read error
>   Dec  2 13:56:33 ... kernel: [...] sr 2:0:0:0: [sr0] CDB:
>   Dec  2 13:56:33 ... kernel: [...] Read(10): 28 00 00 00 69 b8 00 00 40 00
>
> What do you get from
>
>   xorriso -outdev /dev/sr0 \
>           -check_media use=outdev \
>           data_to=/sdb1/movie.udf \
>           --
>
> (It will at least show error messages directly.)
>
>
> Gene Heskett wrote:
> > Classic slow spinup.
>
> After 33 MiB of reading ?
>
> (We have a bug in the kernel since 2008 which prevents waiting for the
>  drive to become ready after automatic tray loading. But this causes
>  0 bytes of read result and lets dd end immediately.)
>
>
> > You can get a better dvd drive
>
> Read failures of decaying drives often show surprising success-or-error
> patterns. Depending on how idvdbackup accesses the drive, its doings
>  might be beneficial.
> But reading in
>
>   http://manpages.ubuntu.com/manpages/bionic/man1/dvdbackup.1.html
>   "-M, --mirror
>                  backup the whole DVD"
>
> i'd expect it to read sequentiall, like dd does.
>
> So more questions to md:
>
> - Does a second or third dd run yield success if no dvdbackup was run
>   inbetween ?
>
> - Does dvdbackup yield a complete set of files if you let it work
>   until it ends on its own ?
>
>
> Have a nice day :)
>
> Thomas
>
Why not prefix that dd command with a sudo udevadm settle command and
only allow the dd command to run on success case?

>

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