[k3b] [Bug 387765] K3b says that blu-ray ISO is not recognizable

[Thomas Schmitt]

https://bugs.kde.org/show_bug.cgi?id=387765

--- Comment #13 from Thomas Schmitt <scdbackup at gmx.net> ---
Hi,

the main riddle now is why the image is not copied to medium after
the warning has been accepted and overridden by the user.

@Leslie:
I propose you create some dummy image file and make test with CDemu
whether K3B accepts it for burning. The dummy could be e.g. a compressed
tar archive. Maybe you can read and verify it from CDemu after the
burn run looks successful.

-------------------------------------------------------------------------

> "sudo mount -t udf -o loop file.iso /mnt/imagemiso" [...] worked after
> I restart my computer.

If the ones say that it is not an ISO 9660 but mount can mount it as UDF,
then there remains only one explanation: It is an UDF without ISO 9660
superblock. Quite exotic and not deserving the name file.iso but rather
file.udf.
(I only have UDFs from mkisofs and Microsoft Inc. DVDs. They all have
 ISO 9660 superblocks.)

What do you get from
  mount -o loop -t iso9660 file.iso /mnt/imagemiso
?
If this refuses then we really have such an UDF.


Userland programmers are surprised:

I am trying to decipher the magic number definition of "file" for
ISO and UDF at e.g.
 
https://sources.debian.org/src/file/1:5.32-1/magic/Magdir/filesystems/?hl=1952#L1937
It looks like the UDF/ISO 9660 distinction by "NSR0" is done only
after a "CDROM Filesystem" was detected by the signature of an ISO 9660
superblock. (The latter starts the former by
  >0    use     cdrom
See man 5 magic, pseudo-types "use" and "name".)

K3B, too, seems to regard UDF as an extension to ISO 9660.


> dd: invalid number: “”

Something did not work with my proposal to determine the byte number
12 bytes before file end. Maybe you could compute it by hand and insert it
into the command line
  dd bs=1 skip=$start count=12 if=file.iso | od -c

Well, since mount -t udf works, my NRG theory loses its probability.


Have a nice day :)

Thomas

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