I tried burning a multi-session dvd-r, but when I try to mount it, I fail. The error message I get is:mount: wrong fs type, bad option, bad superblock on /dev/cdroms/cdrom0, or too many mounted file systemsSee http://lists.debian.org/cdwrite/2004/06/msg00083.html. A.Thanks, I missed it somehow, sorry. I see that it's in the kernel Bugzilla, bug #1930. I used the ide-scsi module, and I've got it mounted, but the files are corrupted. It appears that small files remain ok, but larger files appear truncated. The smallest file where this happened was about 33M, and is truncated to about 840k. It really is truncated: The data is the same as the initial part of the original file. On windows I do see the files correctly.
Sound like 'cruft' option is engaged. Quoting mount(8) manual page "... [cruft option] implies that a file cannot be larger than 16MB." Unless you specify it in mount command line, it most likely gets auto-engaged in your case on files larger than 2G-1 bytes. As for 2GB isofs limitation see http://lists.debian.org/cdwrite/2003/12/msg00101.html.
The udf discs are still unmountable.
Forget udf discs. UDF and multi-sessioning is "no go," not with mkisofs. As you can see yourself, the result is unexpected. A.