CDROM not recognised/opening after install

[Victor Warner]

I have a CD with Knoppix 3.4. Booting and running from the CD went/is fine. Can look and access files from the CD. The computer is a DELL Latitude 510/610. The CD is a removable.

Then did a harddisk install (sudo knoppix-installer). This also appeared to go fine. The computer then booted from hard disk with Knoppix.

However, whether logged in as root or as a user cannot access the CDThere is an icon on the desktop and it shows under Konqueror/devices.

From Konqueror/devices get the following message

"Mount:Special device /dev/cdrom does not exist. Please check that disk is entered correctly"

Also under Konqueror/devices have tried mounting drive and got the above message. Also eject fails.


Any help with this would be greatly appreciated.

Victor Warner

When clicking on desktop icon get the following message:

"Unable to run command specified. The file or folder file:/mnt/cdrom does not exist.

[raj1478]

When clicking on desktop icon get the following message:

"Unable to run command specified. The file or folder file:/mnt/cdrom does not exist.

Follow the following steps: -
1. Delete the shortcut of CDROM from the desktop.
2. Right click on the desktop, click on new and then CDROM.
3. Change the name to whatever you like, click on device tab, select "/dev/cdrom".
4. Click finish.

Try it.

Actually what happens that the link to CDROM on the desktop are to /mnt/cdrom directory, which in turn is a link to /mnt/auto/cdrom. But when the knoppix is installed on harddisk the mount point for the cdrom is at "/cdrom" ...

If unsuccessful try giving the command "mount /cdrom" at the command prompt....

Post the results...

[mr_ed]

First check your fs table to see whether the hd install made an entry for the CD drive. You don't have to be su to do this, just open a terminal window and type cat /etc/fstab or, if you have lots of partitions and hardware, less /etc/fstab (When you're done looking, close less by typing q)

Look for a line that starts out /dev/cdrom - there may also be others that start /dev/dvd and /dev/cdrom-something-else

If you see /dev/cdrom /cdrom iso9660 etcetera (which is how Knoppix set mine up) then that's the problem. Your CD drive isn't at /mnt/cdrom like it might be in other Linux distributions, it's at /cdrom.

If that's the problem, there are different ways to fix it. You can make applications look for the drive where Knoppix decided to mount it for you, or you can change where the thing mounts when you boot.

It's probably easiest to edit /etc/fstab so that the drive is where applications are looking for it. First, from here on, you'll need superpowers, so either su or be prepared to start every command with sudo

Then, to be on the safe side, make a copy of the file sorta like this: cp /etc/fstab /etc/fstab.bak Then open /etc/fstab and change the line /dev/cdrom /cdrom etcetera to /dev/cdrom /mnt/cdrom etcetera

When you're done editing, make sure /mnt/cdrom exists with ls /mnt/cdrom - if it's not there then mkdir /mnt/cdrom.

Just editing /etc/fstab doesn't make anything change until the system reads the file again, such as the next time you boot. There's a way to force it to be re-read, but if your cdrom line has the same options that mine does, then that won't work (unless you feel like editing the options, too).

Instead, just unmount the drive with umount /dev/cdrom and then remount it as type iso9660 with mount -t iso9660 /dev/cdrom /mnt/cdrom and you're done. Remember that you're still superuser, if you are, and decide whether to keep wearing that funny outfit or to change out of it by typing exit or ctrl-d

Now on the other hand ... maybe the hd install didn't write a line to your /etc/fstab for some bizarre reason. In that case, all it takes for a temporary fix is to use the mount command as before, and for a permanent fix add a line to /etc/fstab.

If you have to add the line, and you're not familiar with the options that typically go with cdroms, read the manual for the mount command by typing man mount (because man fstab is fairly useless) and write back to the forum. We'll fill you in on what Knoppix uses by default and why.

Good luck!

-- Ed

[mr_ed]

Or you can do what raj1478 says. I apologize, I was booted into Morphix when I wrote my first reply, and I didn't look closely enough at my Knoppix partition. Bad geek.

When I booted into Knoppix, I found I had a different problem. My /etc/fstab says /dev/cdrom /mnt/auto/cdrom ... which doesn't exist.

So if what raj1478 says doesn't work, tell us what the /dev/cdrom line says in your /etc/fstab.

-- Ed

[Victor Warner]

raj1478 and Ed,

Thank you both for your replies. As suggested I followed raj1478 suggestion (including runing the mount /cdrom command). But after do so I get the following message:

"Could not mount device. The reported error was: mount: special device /dev/cdrom does not exist"

The fstab file reads:

# /etc/fstab: filesystem table.
#
# filesystem mountpoint type options dump pass
/dev/hda1 / ext3 defaults,errors=remount-ro 0 1

proc /proc proc defaults 0 0
/dev/fd0 /floppy vfat defaults,user,noauto,showexec,umask=022 0 0
usbdevfs /proc/bus/usb usbdevfs defaults 0 0
sysfs /sys sysfs defaults 0 0
/dev/cdrom /cdrom iso9660 defaults,ro,user,noexec,noauto 0 0
/dev/dvd /dvd iso9660 defaults,ro,user,noexec,noauto 0 0
/dev/cdaudio /cdaudio iso9660 defaults,ro,user,noexec,noauto 0 0
# Added by KNOPPIX
/dev/hda2 none swap defaults 0 0
# Added by KNOPPIX
/dev/hda3 /mnt/hda3 vfat noauto,users,exec,umask=000 0 0

I can see there are 2 entries for the CDROM but was not sure want to edit or delete.

Victor Warner[/quote]

[mr_ed]

Aha. Yes. Mmmhmmm. Quick Watson, summon Sherlock Holmes!

Here's what I suspect - in fact, what I see in my own installation: Things Which Should Exist But Don't.

Try this: get an expanded directory listing for the relevant items: /dev/dvd, /dev/cdrom, /dvd, and /cdrom. That is, open a terminal window (don't need to sudo) and ls -l /dev/dvd and ls -l /dev/cdrom, and so on.

The ls -l command shows not just whether they exist, but also if they're symlinks - symbolic links, something rather like an enhanced version of a Windows shortcut. Symlinks stand out by having a lower-case L as the first letter on the line, and then at the end of the line the entry you're looking at has an arrow (->) that points to somewhere else.

If you find those, also do ls -l other-place

Each result should be one of 5 possibilities:

- if it doesn't exist, you'll get an error message
- if it's a directory, but empty, a message like total:0
- if it's a directory, not empty, the contents
- if it's a non-linked thing, the listing shows a regular entry with the thing at the right end of the line
- if it's a linked thing, you'll see that arrow

What you're looking for is things mentioned in /etc/fstab that don't actually exist, or things that are symlinked to something else that doesn't exist. In those cases, just changing the desktop shortcut won't fix the problem.

Keep us posted! And especially, if you get to feeling this is all a bit too much ummm, excitement thankyouverymuch, don't just walk away from Linux. There are other varieties that will surely be smoother. Let us know, okay?

-- Ed

[raj1478]

"Could not mount device. The reported error was: mount: special device /dev/cdrom does not exist"

I'm interested in knowing whether you have DVD drive or a CDROM Drive? What type of CD are you putting in the drive? A CDROM or DVD ROM?

The commands suggested above will help. I'll prefer you to give the following commands and post the result: -

1. ls -l /dev/cdrom
2. ls -l /dev/dvd

# /etc/fstab: filesystem table.
/dev/cdrom /cdrom iso9660 defaults,ro,user,noexec,noauto 0 0
/dev/dvd /dvd iso9660 defaults,ro,user,noexec,noauto 0 0

As I can see there are two entries in the fstab file. Try to follow the steps to make a new DVD ROM icon on the desktop, just to try something different and post the results.

Good Luck..

[Victor Warner]

raj1478 and Ed

Thank you for your further messages.

Here is the result of the ls command

sh-2.05b$ ls -l /dev/cdrom
ls: /dev/cdrom: No such file or directory
sh-2.05b$ ls -l /dev/dvd
lrwxrwxrwx 1 root root 10 Feb 12 14:01 /dev/dvd -> /dev/cdrom

I tried creating new DVD ROM but the error message was still the same (and tried several combinations

I have a CDROM, and I have tried different types of CDs, data CDs (such as original CDs provided by software suppliers, homemade one's) and original audio CDs. None of which I could access.

Victor Warner[/quote]

[raj1478]

sh-2.05b$ ls -l /dev/cdrom
ls: /dev/cdrom: No such file or directory
sh-2.05b$ ls -l /dev/dvd
lrwxrwxrwx 1 root root 10 Feb 12 14:01 /dev/dvd -> /dev/cdrom

There is the problem. You don't have the cdrom device in your /dev directory, and the symlink /dev/dvd is also pointing to it, that is why the second option of DVD icon is also not working.

The solutions to problem are a few: -

If I'm correct then there is file named MAKEDEV or MKDEVICE or something like this in the /dev directory. Try executing "<watever name you find> /dev/cdrom" and try again to mount the CDROM.

If unsuccessful then try to execute the command "MAKEDEV" without any arguments.

Post the results...

[Victor Warner]

raj1478

Thank you for message

In Konsole (as root) I typed the following as suggested and got the following results

1.
root@DELL:/dev# MAKEDEV /dev/cdrom
/sbin/MAKEDEV: don't know how to make device "/dev/cdrom"

2.
root@DELL:/dev# MAKEDEV
root@DELL:/dev#


I trried creating a new CD ROM device but still got the same error message

Victor Warner