I pulled the IDE CD-ROM drive out of my main Linux box today and replaced it with a SCSI model, mostly because I like to keep a spare IDE CD-ROM drive loose and I had a couple of Toshiba 4X CD-ROM drives in my closet. I don’t use the CD-ROM drive in my Linux box very much, so a 4X is fine. Plus, making my Linux box into an all-SCSI system means I can compile out all the IDE support in my kernel if I ever feel ambitious.
I can never remember how to tell Linux I’ve swapped drives though. I’ve had to do this a number of times because not all my SCSI cards support bootable CDs, but all of my systems can boot off an IDE CD-ROM drive, so all too often I do my Linux install with an IDE drive.

The trick is to remember that SCSI CD-ROM devices are named srx, where x is a number. So when I installed a single SCSI CD-ROM, it became sr0.

So I went into /etc/fstab and found a line that looked like this:

/dev/cdrom /cdrom iso9660 defaults,ro,user,noauto 0 0

As far as I can tell, /dev/cdrom is a special device Debian creates during installation. I changed it to this:

/dev/sr0 /cdrom iso9660 defaults,ro,user,noauto 0 0

Now I can mount a cdrom from a command line with this command:

mount /cdrom