Re: How to verify newly burned disc
Hi,
On Tue, 29 Jun 2021 12:08:13 +0200
"Thomas Schmitt" <scdbackup@gmx.net> wrote:
(...)
>
> > For data-discs I finally found a recipe that seems to
> > work in the archives of debianforum.de :
> > $ wc -c whatever.iso
> > 8237400064 whatever.iso
> > $ dd if=/dev/sr0 | head -c 8237400064 | md5sum
>
> Yes. See also the FAQ about Debian ISO images:
> https://www.debian.org/CD/faq/#verify
>
> The trick is to curb the reader to the size of the ISO image for which
> you know the checksum.
> The ISO images themselves contain a data field with their filesystem
> size. This may or may not be the size of the ISO image file.
> So it is better to record both, image size and checksum for the purpose
> of later verification.
thanks for the detailed explanation.
I managed to wrap these commands in a little script, so now I can do this
with a single command, I think this wil do the trick for my purpose.
> > Unfortunately there is apparently no way to control the reading
> > speed here, so maybe one should be careful with these Pioneer
> > drives :)
>
> You would need a filter program which takes care not to read more than
> ~ 20 MB/s. Then the drive slows down automatically.
>
> (It is not decided who is at fault with the BD-RE cracks: Pioneer or
> Verbatim or both ...)
I see, that does not sound trivial, at least to me :)
Fortunately there seems to be no danger with the Asus drive here, it does
not sound like it is spinning unreasonably fast when when using dd, so I
think it should be save just to skip this step.
> > So, does anyone know about a way to verify the integrity of burned
> > audio-CDs?
>
> Success is normally judged by playing the CD on the intended player
> device, which in most cases is not the CD burner.
>
>
> Difficulties are to be expected if you want to verify the burn success
> by audio data comparison:
>
(...)
Ok, I thought so. Checking success by listening to the CD playing on my
stereo will be good enough, I guess. And I`ll just assume that if data
discs are ok the same will be true for audio-CDs.
So far the Asus managed to pass all tests, so probably I should just be
grateful to all the transcendental authorities that guided my hand when I
picked that carton from the shelf :)
Thanks again for your patience, and have a nice day :-)
Michael
.-.. .. ...- . .-.. --- -. --. .- -. -.. .--. .-. --- ... .--. . .-.
Compassion -- that's the one things no machine ever had. Maybe it's
the one thing that keeps men ahead of them.
-- McCoy, "The Ultimate Computer", stardate 4731.3
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