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I have a HL-DT-ST DVD-RAM GH22NP20 DVD writer and I'm unable to read blank DVDs ( only Benq 16X DVD-R at hand ). Surprisingly enough, after I wrote some content on them with another drive I can read them with the initial one.

In dmesg I get messages like

cdrom: This disc doesn't have any tracks I recognize!
end_request: I/O error, dev sr0, sector 0
Buffer I/O error on device sr0, logical block 0
end_request: I/O error, dev sr0, sector 0

Does this happen because of a compatibility problem or due to a hardware fault?


Update: Nero under Windows works just fine, so it's probably a Linux issue.

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Do you have software that tries to automatically mount a disk when it's placed in the drive? A file manager maybe, or some part of your desktop environment? My linux is headless, so I can't help much further on those lines, except to say I have noauto in the /etc/fstab options field for my CD/DVD mount point.

If you ignore the message, are you still able to write to the blank disk?

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Well yes, possibly hal is trying to automount it. I usually burn with k3b and I'm unable to do so since no disk is detected. – Robert Munteanu Jul 24 '09 at 17:24
    
It could also be trying to mount it with a udf filesystem instead of iso9660 (or the other way around). – pgs Jul 24 '09 at 17:35
    
Mounting works fine, writing does not. – Robert Munteanu Jul 24 '09 at 17:49

The error messages you cite are expected.

Blank doesn't mean "filled with zeros"; it means there aren't any tracks at all. What you have looks like, to reads, a 0 length disk.

A nice upside to this is that you can easily get (data) CD images by just reading from the drive. If you burn a 30M image to a 700M CD and then

dd if=/dev/dvd of=foo.iso

foo.iso will be 30M, not 700M. You get only the data you care about; you don't need an image of the blank parts of the disk.

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up vote 0 down vote accepted

Considering the permissions on the disk device

rw-rw----+ 1 root disk 11, 0 2009-07-30 00:04 /dev/sr0

And the fact that I was not in the disk group it all makes sense now. A little usermod -G magic to add me back to the disk group made things get back to normal.


That being said, I can't for the life of me understand the error messages.

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