Help setting up my CDRW and my DVD Rom drive

QzarBaron · 02-04-2005, 09:24 PM

Ok here is the deal. I know my CDRW drive is /dev/hdc and my DVD drive is /dev/hdd. The problem is my cdrom symlink is set to /dev/hdd and my dvd symlink is set to /dev/hdd also. I tried creating a link called cdrw that would point to /dev/hdc and it would get erased every time I rebooted(and it also wouldn't work)

My fstab looks like this

Code:

/dev/hda7        swap             swap        defaults                0   0
/dev/hda5        /                ext3        defaults                1   1
/dev/hda6        /home            ext3        defaults                1   2
/dev/hda2        /mnt/win-c       ntfs        auto,ro,umask=000       1   0
/dev/hda8        /mnt/shared      vfat        auto,rw,umask=000       1   0
/dev/cdrw        /mnt/cdrom       iso9660     noauto,user,ro,unhide   0   0
/dev/dvd         /mnt/dvd         iso9600     noauto,user,ro,unhide   0   0
/dev/fd0         /mnt/floppy      auto        noauto,owner            0   0
devpts           /dev/pts         devpts      gid=5,mode=620          0   0
proc             /proc            proc        defaults                0   0

right now oddly enough I have 3 devices... cdrom(which points to my dvd drive), cdrw(which gives me an error which I will post at the end), and dvd(which points to nothing)

it's really odd.

the error I get when I try to run cdrw is:

mount: wrong fs type, bad option, bad supermount on /dev/cdrw... etc.

Any ideas?

tw001_tw · 02-04-2005, 11:11 PM

You know, I've always wondered why I get a /dev/cdrom after an install.

But I change my fstab to:
/dev/hdc - > /mnt/dvdburner
&
/dev/hdd -> /mnt/dvd
(i.e. - I don't use /dev/cdrom or /dev/dvd )

Maybe theres an advantage I am not getting from doing it this way. If there is,
I'de like to know. But so far, it works for me.
-tw

shilo · 02-05-2005, 12:09 PM

Hey guys. Are you using a 2.6.x kernel? Are you using UDEV? If so, you'll see this happen. The last optical drive gets the cdrom symlink. This is due to /etc/udev/scripts/make_extra_nodes.sh wqhich looks something likie this:

Code:

# If we can, add a default /dev/cdrom and /dev/dvd link:
#if /bin/ls -l /dev | grep -w cdrom 1> /dev/null 2> /dev/null ; then
#  ( cd $udev_root
#    /bin/ls -l * | grep -w cdrom | cut -f 2 -d : | cut -f 2 -d ' ' | while read optical_device ; do
#      # It has to be a cdrom.  Last one wins.
#      ln -sf $optical_device cdrom
#      # If it's a DVD, set that link as well:
#      if grep -i dvd /proc/ide/$optical_device/model 1> /dev/null 2> /dev/null ; then
#        ln -sf $optical_device dvd
#      fi
#    done
#    unset optical_device
#  )
#fi

Note that I have it all commented out. If you want solid naming of your devices, use udev rules. Create a file /etc/udev/rules.d/local.rules . You can google for how to write them, but here is mine if you want something to give you an idea how it's done: (hope it doesn't wrap. If it does, there are four lines, two commented out, and two that start with "BUS=")

Code:

# Optical Devices
# Added by Shilo 09/12/2004
BUS="ide", KERNEL="hdc", NAME="%k", SYMLINK="dvd dvdrw cdroms/dvdrw cdroms/cdrom0", GROUP="cdrom", MODE="0660"
BUS="ide", KERNEL="hdd", NAME="%k", SYMLINK="cdrom dvdrom cdroms/dvdrom cdroms/cdrom1", GROUP="cdrom", MODE="0660"

A quick guide:

BUS="ide" "Hey, Mr. UDEV. If you come across an IDE drive..."

KERNEL="hdc" "...who's kernel name is hdc..."

NAME="%k" "... I want you to make a device and name it the same as the kernel (/dev/hdc)."

SYMLINK="dvd dvdrw cdroms/dvdrw cdroms/cdrom0" "Please also make four symlinks to /dev/hdc. Call them /dev/dvd, /dev/dvdrw, /dev/cdroms/dvdrw, and /dev/cdroms/cdrom0."

GROUP="cdrom" "When you make this device and symlinks, please put them in the cdrom group..."

MODE="0660" "... and give them permissions 0660 (same as 660)."

You'll see that I have two optical drives. With my rule, each are assigned the symlinks that I want. As a note, I chose the symlinks that I did in order to make set up of some programs easier. Totem, gxine, most cd-players, etc look for things like /dev/dvd or /dev/cdrom by default. The old way of doing things was to manually make a symlink in /dev to the appropriate device. If you do that with udev, the symlinks are wiped out at reboot. Also, I like using the cdrom group with 660 permissions. Then, when I use k3b, I set it up to use a burning group, called cdrom. Just make sure that the users you want using the optical drives are in the cdrom group.

tw001_tw · 02-05-2005, 11:03 PM

shilo comes through again.
Great explination - thanks

-tw