/dev/cdrom* disappeared

ecko · Tux's lil' helper Joined: 04 Jul 2010 Posts: 102

Hello,

I seldom use cdrom/dvd device, but in the recent weeks I noticed that that the /dev/cdrom* and /dev/dvd links disappeared from the virtual filesystem. I then configured software with dev=/dev/hdc (mplayer, xine) or dev=1001,0,0 (cdrecord). It works, but it is now necessary to launch the software as root to access the data or play the movie, although the normal user belongs to the usual groups (audio cdrom video cdrw plugdev etc.). I don't use anything fancy (no automounter, I use fluxbox and the command line). What has “recently” changed (I have not used my cdrom drive for around a year) and what can I now do to access optical media as normal user?

I use gentoo (mostly) stable on amd64, vanilla-sources 2.6.35.5, udev-151-r4

Thanks for help,
ecko

NeddySeagoon · Posted: Wed Sep 22, 2010 7:37 pm Post subject:

ecko,

udev no longer makes /dev nodes for /dev/hd... you need to migrate to libata
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

ecko · Tux's lil' helper Joined: 04 Jul 2010 Posts: 102

Hi, thanks for the answer. Since this migration needs some time and care I'll do over the week-end and report problems if any. [By the way you say in you guide that it should be too late already (my system should not boot anymore). Yet I have all the /dev/hda nodes for my internal IDE hdd and my system is usable. Good that I did not find the problem too late; ]

NeddySeagoon · Posted: Wed Sep 22, 2010 8:46 pm Post subject:

ecko,

That means that you have an old udev - so this may not be your problem.
Most users find out about /dev/hd... going away when the system will not boot because the /dev/ node for the root filesystem is missing.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

ecko · Tux's lil' helper Joined: 04 Jul 2010 Posts: 102

Just to let now the end to people who might have found this page through a search engine: switching to libata solved the issue; /dev/cdrom is now again a valid link (to /dev/sr0)

But it is not necessary to switch from /dev/hda to /dev/sda in the /etc/fstab. One can use the labels and UUID. Say, one's system works or the disk has been mounted using a livecd, either as /dev/hda or /dev/sda. Then launch /sbin/e2label to set the label name

Example, on my disk, the /dev/hda1 contains the /boot directory, let's call it "Boot." /dev/hda3 contains the root, let's call it "Root."
(In this example I assume the old kernel config where hdxx is used instead of sdxx, but of course it works the same with both notations. I uses here the partition scheme of my disk, one must adapt the number to his partitions.)

NeddySeagoon · Posted: Fri Oct 22, 2010 9:10 pm Post subject:

ecko,

What do you use in grub.conf ?
Do you have an initrd ?
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

ecko · Tux's lil' helper Joined: 04 Jul 2010 Posts: 102

I don't use initrd (if someone can explain what I could gain using it if all the drivers required at boot are compiled inside the kernel).

NeddySeagoon · Posted: Sun Oct 24, 2010 2:13 pm Post subject:

ecko,

Hmm, you use the default root=, built into the kernel when its complied. It uses whatever it finds the local root filesystem on.
That will be the /dev/sda3 or whatever.

I thought you used root=LABEL=<root_fs_label> or maybe the UUID form.
I know the UUID form needs an initrd but I'm not sure about LABEL.

All you would gain from an initrd is to be able to mount root the same way as you identify partitions in /etc/fstab
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.