cannot mount my cdrom

[georgedelajungla]

Hi everybody
anyone could give me an advice on how to solve this problem?

I have Red Hat 7.2
I only have a LG CD-RW CED-8080B
When i click on the CD-ROM icon or try to mount it, I become the
following message:
"The device could not be mounted
mount: /dev/cdrom: unknown device"

I'm a novice in linux, but an expert tried to help me and couldn't solve the problem.
Waiting for your help. Best regards.

[Dolda2000]

Do you have the /dev/cdrom file? If you don't, run these commands:

su -
(Enter your root password)
ln -s hdc /dev/cdrom

[georgedelajungla]

thanks.
well, yes, it seem so, 'cause the answer was:

ln: '/dev/cdrom': the file exists

and now, should i send you the file?

[Dolda2000]

Certainly not. It's supposed to be the CD-ROM drive. Instead, check what these commands return:

ls -l /dev/cdrom
ls -lH /dev/cdrom
cat /etc/fstab

I must also say that "unknown device" seems like a strange error message. It's not a system standard one. Did you translate it from another language? Otherwise, could you check so that it is precisely that it says, and if it really is, please insert a CD into the drive and run "mount /dev/cdrom" and see what it says.

[georgedelajungla]

Yes and no :-O The error message is partially in another language (spanish), but not this 2 words; the complete and original message is:

No se pudo montar el dispositivo.
El mensaje de error fue:
mount: /dev/cdrom: unknown device

I guess you should also know that it's not a hardware problem, since i have on that computer Windows too, and in Windows i can use the cdrw perfectly.

your commands:

ls -l /dev/cdrom
returns
lrwxrwxrwx 1 root root 9 jun 17 14:34 /dev/cdrom -> /dev/scd0

ls -lH /dev/cdrom
returns
ls: Warning: the meaning of '-H' will change in the future to conform to POSIX.
Use '--si' for the old meaning.
lrwxrwxrwx 1 root root 9 jun 17 14:34 /dev/cdrom -> /dev/scd0

cat /etc/fstab
returns
LABEL=/ / ext3 defaults 1 1
LABEL=/boot /boot ext3 defaults 1 2
none /dev/pts devpts gid=5,mode=620 0 0
none /proc proc defaults 0 0
none /dev/shm tmpfs defaults 0 0
/dev/hdc3 swap swap defaults 0 0
/dev/cdrom /mnt/cdrom iso9660 noauto,owner,kudzu,ro 0 0
/dev/fd0 /mnt/floppy auto noauto,owner,kudzu 0 0

mount /dev/cdrom
returns
mount: /dev/cdrom: unknown device

what do you think?

[Dolda2000]

It would seem that your SCSI emulation isn't turned on properly. What physical device is your CD-ROM (ie. what place on which IDE bus does it have)?

I deleted the first of your duplicate posts. You didn't mind, did you?

[georgedelajungla]

no, i don't mind it at all; excuse me, i didn't want to send it twice ... and after i didn't know how to remove it

well, as i said, i'm a novice at linux but ... i don't understand why do i need SCSI emulation , since i don't have a scsi driver, but just IDE ones.

- I have a Hard Disk of 20 Gb (with Windows installed) as the master device
in the primary bus.
- I have a 2nd Hard Disk of 6 Gb (with Red Hat installed) as the master
device in the secondary bus.
- And I have the CDRW as the secondary device in the primary bus

Best,

[Dolda2000]

The reason you need SCSI emulation is because it is a CD burner. Don't get me wrong, Linux fully supports IDE burners and all, but there are no actual programs to burn to IDE burners. They all use the SCSI interface. Why there hasn't come any IDE burner programs for Linux, I don't know.

Anyway, check what the following commands return.

cat /proc/ide/hdb/driver
/sbin/lsmod
cat /proc/cmdline
cat /etc/modules.conf

hdb is the designation for the primary slave in Linux.
The last command needs to be run as root.

I didn't want to make you feel bad about posting twice, I just wanted to check so that everything was as I though.

[georgedelajungla]

ok, thanks for the explanation about scsi.
anyway, don't care, i don't want to burn cds with linux, just want to read them.

the commands:

cat /proc/ide/hdb/driver
returns
ide-scsi version 0.9

/sbin/lsmod
returns
Module Size Used by
es1370 27232 1 (autoclean)
gamesport 1840 0 (autoclean) [es1370]
soundcore 4208 4 (autoclean) [es1370]
binfmt_misc 6064 1
autofs 11232 0 (autoclean) (unused)
8139too 12640 0
ide-scsi 7872 0
scsi_mod 92208 1 (ide-scsi)
ext3 61936 2
jbd 38976 2 [ext3]

cat /proc/cmdline
returns
ro root=/dev/hdc2 hdb=ide-scsi

cat /etc/modules.conf
returns
alias parport_lowlevel parport_pc
alias eth0 8139too
alias sound-slot-0 es1370
post-install sound-slot-0 /bin/aumix-minimal - f /etc/.aumixrc -L >/dev/null 2>&1 || :
pre-remove sound-slot-0 /bin/aumix-minimal - f /etc/.aumixrc -S >/dev/null 2>&1 || :
alias char-major-81 bttv
You have new mail in /var/spool/mail/root

[Dolda2000]

Add these lines to your /etc/modules.conf, then reboot:

options ide-cd ignore=hdb
alias block-major-11 sr_mod
add above sr_mod ide-scsi

(And yes, there are ways to avoid a reboot - this is Linux, after all - but it's the easiest way for me to explain)