Hey all,
I am having issues with my cd-rom setup on RH Linux 7.2 After installing RH onto my box, I have been unable to mount any cdrom into it. I have looked into different forums, all suggesting different things, none working. The error I get from dmesg is as follows when I mount the drive using
mount -t iso9660 /dev/scd0 /mnt/cdrom


ide-scsi: hdc: unsupported command in request queue (0)
end_request: I/O error, dev 16:00 (hdc), sector 64
isofs_read_super: bread failed, dev=16:00, iso_blknum=16, block=32

The command completes but an error message of "No medium found" appears

mount: block device /dev/scd0 is write-protected, mounting read-only
mount: No medium found

I tried using /mnt/cdrom but that maps to /dev/hdc which gives me the error
mount: wrong fs type, bad option, bad superblock on /dev/hdc,
or too many mounted file systems
(could this be the IDE device where you in fact use
ide-scsi so that sr0 or sda or so is needed?)

I then made the symlink to /dev/scd0 on /dev/cdrom and still no luck. I get the same message of No medium found

I've also ran depmod -ae resulting in no change when I run the mount commands.

Also I've checked to make sure that scsi support is installed and it is.

The specs on the system are:
1 DAC960 RAID controller ( 5 drives, 1 of which is a spare ) total HD size ~ 100GB
1 50x cdrom
1 floppy
512 MB RAM ( ECC registered)

the cdrom is connected to the mainboard which looks like it's an EIDE controller but I am probably wrong.

Any comments or suggestions would be appreciated.

thanks
Michael Nguyen

Why do you need scsi emulation on your IDE cd-rom? If the emulation is turned on on /dev/hdc then system is no longer aware that there is /dev/hdc exists on the system that's why you get
mount: wrong fs type, bad option, bad superblock on /dev/hdc

It seems that your cdrom isn't handling being an emulated scsi device. Turning off SCSI emulation is the easiest. If its not a burner, you really don't need it. Open up lilo.conf or grub.conf and edit out the line: "append hdc=ide-scsi". Then re-run lilo or grub. This will make the cdrom device turn back into a regular IDE device that is moutable as /dev/hdc.

Cheers,

Finegan

Just a bit of clarification to fin's post: if you are using grub you don't have to rerun it. Try also removing ide-scsi module
/sbin/rmmod ide-scsi

I've turned off ide-scsi mod using rmmod ide-scsi. I removed from my grub.conf file hdc=ide-scsi

still no go

Here's my grub.conf file:

# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that
# all kernel and initrd paths are relative to /boot/, eg.
# root (hd0,0)
# kernel /vmlinuz-version ro root=/dev/rd/c0d0p2
# initrd /initrd-version.img
#boot=/dev/rd/c0d0
default=0
timeout=10
splashimage=(hd0,0)/grub/splash.xpm.gz
password --md5 $1$NapÒ.iTÀ$jWKTQIqkXJrodR6rnoTUj.
title Red Hat Linux (2.4.7-10)
root (hd0,0)
kernel /vmlinuz-2.4.7-10 ro root=/dev/rd/c0d0p2
initrd /initrd-2.4.7-10.img

what does /sbin/lsmod look like?

Module Size Used by
ide-cd 27072 0 (autoclean)
vfat 9584 0 (autoclean)
umsdos 26112 0 (autoclean)
msdos 5360 0 (autoclean) [umsdos]
fat 32384 0 (autoclean) [vfat umsdos msdos]
sr_mod 15360 0 (autoclean)
cdrom 28512 0 (autoclean) [ide-cd sr_mod]
ufs 55232 0 (autoclean)
sg 28608 1 (autoclean)
parport_pc 14768 1 (autoclean)
lp 6416 0 (autoclean)
parport 25600 1 (autoclean) [parport_pc lp]
autofs 11520 0 (autoclean)
nfsd 70720 8 (autoclean)
lockd 52880 1 (autoclean) [nfsd]
sunrpc 64688 1 (autoclean) [nfsd lockd]
eepro100 17664 1
st 26240 0
ext3 64624 2
jbd 40992 2 [ext3]
aic7xxx 114544 1
DAC960 57760 4
sd_mod 11584 0 (unused)
scsi_mod 95664 5 [sr_mod sg st aic7xxx sd_mod]

/sbin/rmmod sr_mod

what does this mod do? I did a modinfo on sr_mod and nothing useful to me was returned. I don't want to remove this mod if it will affect the other scsi devices on the system. ( ie the RAID-5 drives)

Thanks for your help

http://suiling.princeton.edu/users/linux/cdwriting.txt
It pertains to /dev/scd*, which obviously you don't need, you are trying to get rid off scsi emulation, right?

I'm trying to get the cdrom to work. I can eject it, but I can't mount any CD. I have a RAID Array connected to a DAC960 SCSI card and a tape drive attached to a SCSI card as well. The cdrom and floppy are attached to the main board's ide connectors.
Hope that helps...

ok removed the module sr_mod and the cdrom still won't mount. I still receive the No medium found message.

mount /dev/hdc /mnt/cdrom/
mount: block device /dev/hdc is write-protected, mounting read-only
mount: No medium found
[root@opus root]# mount /dev/hdc /mnt/cdrom/
mount: block device /dev/hdc is write-protected, mounting read-only
mount: No medium found
[root@opus root]# mount /dev/hdc /mnt/cdrom/
mount: block device /dev/hdc is write-protected, mounting read-only
mount: No medium found
[root@opus root]# mount /mnt/cdrom
mount: No medium found
[root@opus root]# mount /dev/cdrom /mnt/cdrom/
mount: block device /dev/cdrom is write-protected, mounting read-only
mount: No medium found
[root@opus root]#

Any other suggestions?

if anyone knows a solution i am having the exact same problem. i'm not using ide-scsi at all and can mount one drive but not the other....VERY VERY strange. please help!!

I had the same problem and here is how I fixed it. I went in to /etc/fstab and chaged to look like this
/dev/scd0 /mnt/cdrom iso9660 noauto,user,ro 0 0
then I used this to link every thing: ln -sf /dev/scd0 /mnt/cdrom
and then like magic every thing worked let me know if that helped.??
I also chmoded /dev/scd0 to 777 cause it was only rw rw try that