Wodim unable to write on DL DVD Drive

[Preston Hagar]

On Tue, Apr 2, 2013 at 7:24 PM, JD <jd1008 at gmail.com> wrote:

>
>
>>  $ /opt/schily/bin/mkisofs -iso-level 3 -print-size dvd.iso
>
> Setting input-charset to 'UTF-8' from locale.
> Total extents scheduled to be written = 2391761
> 2391761
>
> $ /opt/schily/bin/mkisofs -iso-level 4 -print-size dvd.iso
> Warning: Creating ISO-9660:1999 (version 2) filesystem.
> Warning: ISO-9660 filenames longer than 31 may cause buffer overflows in
> the OS.
>
> Setting input-charset to 'UTF-8' from locale.
> Total extents scheduled to be written = 2391762
> 2391762
>
> Why the difference in output?
>
>
>
My understanding (I'm not an expert on DVDs by any means) is that there was
an issue with ISO files larger than 4 GB in early version of cdrtools
(mkisofs, cdrecord, etc).  Since DVDS are 4.7 GB (or 4.4 GB or 4.3 GB
depending on who you ask and how), the 4 GB limit meant that most DVDs
could still be burned.  With dual layer DVD, blu ray, etc, that 4 GB limit
gets passed all the time.

Jorg Schilling (the cdrtools guy) wrote a fix for it using ISO-9600
muti-extent files, but some versions of the Linux kernel had a bug that
meant that his fix wouldn't work.  I think (not sure) that the bug has been
fixed in all newish versions of the kernel.  Because of that bug, cdrecord
and mkisofs still default to not useing the multi-extent file code since it
is more tested and works with more kernels (as long as the file is smaller
the 4 GB).  When the file is larger than 4 GB, you have to use the
-iso-level flag to make it use the multi-extent file code.


Clear as mud right?


Here is a little more rom the man page if it helps any:


-iso-level level
              Set the ISO-9660 conformance level. Valid numbers are 1..3
and 4.

              With level 1, files may only consist of one section and
filenames are restricted to 8.3 characters.

              With level 2, files may only consist of one section.

              With level 3, no restrictions (other than ISO-9660:1988) do
apply.  Starting with this level, mkisofs also allows files to be larger
than 4 GB by implementing ISO-9660 multi-extent files.

              With all ISO-9660 levels from 1..3, all filenames are
restricted to upper case letters, numbers and the underscore (_). The
maximum filename length is  restricted  to  31  characters,  the  directory
 nesting  level  is
              restricted to 8 and the maximum path length is limited to 255
characters.

              Level 4 officially does not exists but mkisofs maps it to
ISO-9660:1999 which is ISO-9660 version 2.

              With  level 4, an enhanced volume descriptor with version
number and file structure version number set to 2 is emitted.  There may be
more than 8 levels of directory nesting, there is no need for a file to
contain a dot
              and the dot has no more special meaning, file names do not
have version numbers, the maximum length for files and directory is raised
to 207.  If Rock Ridge is used, the maximum ISO-9660 name length is reduced
to 197.

              When creating Version 2 images, mkisofs emits an enhanced
volume descriptor which looks similar to a primary volume descriptor but is
slightly different. Be careful not to use broken software  to  make
 ISO-9660  images
              bootable by assuming a second PVD copy and patching this
putative PVD copy into an El Torito VD.



You might Google a little further on cdrtools, multi-extents and 4GB files.


Preston
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.ubuntu.com/archives/ubuntu-users/attachments/20130403/45c44e0c/attachment.html>