Re: [Dvdrtools-users] problems reading back a burned dvd-r

[Volker Kuhlmann]

> i have a toshiba-1612 dvd-reader,
> and recently i bought a pioneer-105 dvd-rewriter.
> 
> i burned two imation dvd-r medias.. i don't know if they are 1x, 2x, or
> 4x medias, cdrecord successfully burned them at 2x.
> 
> now the problem is that these dvd-r medias can be read in the toshiba
> drive without problems, but they can't be read in the pioneer driver (
> in 50% of cases i'm unable to mount it, in the remaining 50% i mount it,
> but get an i/o error when i try to read them). in the toshiba drive

I had a similar experience, Sony DR?500U?? writer with 2.0c firmware,
Aterra DVD-R media, cdrecord-prodvd personal edition. The media doesn;t
say speed, but the internet says 2x. The first burnt fine at 2x, no
errors. Not even the dvd burner could read a single bit of it. The
second one at 1x died half way through with a media error.

Since then I found out that there's firmware 2.0f for the drive, which
among other things "fixes reliability issues", haha. The same setup
writes Verbatim DVD-RW and Apple DVD-R just fine.

It seems unlikely to me that cdrecord has an effect on this. The drive
is simply not able to burn that specific type of media. Wrong laser
power, whatever, who knows. Maybe a new manufacturer came up with new
media parameters which the drive simply didn't know about. The
technology is relatively new.

Check you have the newest firmware for your dvd burner, if you have
already, switch media. Dump the disks, they're coasters. There's
nothing wrong with your reader.

Btw, the Linux kernel has a most annoying "feature" of trying to read
past the end of the disk recording. cat /dev/cdrom has almost never in
kernel history given the correct amount of data back (some kernels have
paniced!). cdrecord -pad used to fix it, but now it's nowhere near
enough and I/O errors are usual and I've seen 50 blocks(!) before end
of media on CDs, probably the same number of blocks on DVDs (but their
blocks may be 8 or 16 times as large). Very annoying when you want to
verify your CDs with md5s of the iso image. Always append 2MB worth of
/dev/zero to the end of your iso file before writing.

Volker

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