Last Updated on September 30, 2010 by Dave Farquhar
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
David Farquhar is a computer security professional, entrepreneur, and author. He started his career as a part-time computer technician in 1994, worked his way up to system administrator by 1997, and has specialized in vulnerability management since 2013. He invests in real estate on the side and his hobbies include O gauge trains, baseball cards, and retro computers and video games. A University of Missouri graduate, he holds CISSP and Security+ certifications. He lives in St. Louis with his family.
On all my Debian systems, /dev/cdrom is a symbolic link to the real CDROM. So I always just remove the link and relink it.
rm /dev/cdrom
ln -s /dev/sr0 /dev/cdrom
Then it’s right for the foreseeable future and I don’t have to mess with /etc/fstab (and automounters if you run such things; I don’t).
Note too that either way you do it, you need to make sure that the real CDROM device in /dev is owned by group “cdrom” and group-readable.