files "vanished" from cd-rom

otoomet · 11-25-2004, 01:47 AM

Hi,

a couple of months ago a friend of mine saved some pictures on a cd. It worked well on all my linux computers.

Yesterday I wanted to add some more files to it (it is a multi-session cd). For my surprise, the cd showed up as empty. Well, not completely. xcdroast claimed that it has 2 audio tracks (there were 2 sessions from before).

I burned my files onto it, but cd seemed still to be empty. Well, I discovered that it is mounted with udf and not iso9660 fs. I remounted it manually using iso and voila -- now the last session showed up. But not the previous two.

Is there any way to make it clear to the system that all sessions are iso and not udf?

Best,

Ott

nukkel · 11-25-2004, 02:52 AM

There is a cool filesystem called "CDfs" that lets you mount a cd and then shows each tracks/sessions as a *file*. A .wav for audio tracks and a .iso for sessions. So you can "extract" whatever session you wish, by simply copying the corresponding file to a hard disk, and access the data on it by mounting it through a loop device, or by burning it to a new CD-R.

There are detailed examples on the website of CDfs:
http://www.elis.rug.ac.be/~ronsse/cdfs/cdfs.html

Keep in mind you'll have to compile and insmod it manually.

greets
nukkel

otoomet · 12-03-2004, 08:07 AM

cdfs seems interesting. But still, cannot I simplymount the CD so that everything appears as ISO filesystems? Currently, fstab has the line

Code:

/dev/cdrom              /mnt/cdrom              udf,iso9660 noauto,owner,kudzu,ro 0 0

What if I remove udf option? Are there a way to enforce iso9660 to be the preferred fs (man mount states it is the "default")? How can it be that computer "rethinks" what is the fs on a CD? Can the autodetection be improved somehow, e.g. by CD titles?

Best,

Ott

nukkel · 12-03-2004, 03:39 PM

What I did on my computer is use a seperate mount point to force a certain type. So I had e.g.

Code:

/dev/cdrom              /mnt/cdrom              auto       noauto,... 0 0
/dev/cdrom              /mnt/cd-tracks         cdfs        noauto,... 0 0
/dev/cdrom              /mnt/cd-udf              udf         noauto,... 0 0

Then I can choose the FS by mounting the corresponding directory.

I do not know if there is another way to enforce a preferred FS type, but this works for me, although I must admit it's a bit "messy"...

About improving the autodetection, I don't think that can be easily done. AFAIK, the system tries every FS in /etc/filesystems and /proc/filesystems, using some "magic" bytes on the boot sector of the device to see if it is of that type.
Maybe you could try to change the order of the FS types in /etc/filesystems?

Other than that, I can't tell much more.

hope you find a solution,
nukkel

otoomet · 12-12-2004, 07:58 AM

I (well, actually my brother) discovered the option 'session=' for mounting cd. The results are a bit strange, but I can access all my files. The cd has 4 sessions (0-3). When I mount with session=0, I get access to session 0. Session=1 gives both 0 and 1, session=2 -> 2 and session=3 ->3.

I was expecting that I get all the sessions by default mount, but, anyway, it is not a problem.

Thanks for suggestions!

Ott