How can I backup Compact Disc media to ISO files on Ubuntu?

Problem: I created 3 DVD's filled with Windows system recovery disks in case I ever have a hardware problem and need to re-install Windows in order to run diagnostic tests. However, I don't want to worry about losing them, so I would like to make backups of the recovery disks as ISO images which I can store on an external hard drive.

A Google search revealed that I can do this using the dd (or "disk dump") unix command.

dd if=/dev/who-knows-where? of=/home/wdkrnls/x201-recovery-2011-09-30.iso

But the snag is that Ubuntu doesn't use the old convention of associating /dev/cdrom with the cd-rom drive. Instead Nautilus automagically creates /media/CD_ROM which is a directory, and not the drive itself. I tried to run dd anyways and got:

/bin/dd: reading '/media/CD_ROM/': is a directory 0+0 records in 0+0 records out 0 bytes (0 B) copied, 0.0158501 s, 0.0 kB/s

I tried running dmesg | tail and saw a reference to:

[215135.134164] sr 9:0:0:0: Attached scsi generic sg1 type 5

So I tried ls /dev/sg1, but there wasn't any file called that. Only my partitions show up with sudo fdisk -l, leaving me stumped as to what to try next.

Solution: I figured out I could solve my problem with brasero or k3b and so abandoned my exploration of Ubuntu's internals. Nevertheless, I still wouldn't mind knowing how I would use dd to accomplish the same task.

How would I solve my problem with dd?

Solution 1:

Load a CD in the drive so it mounts. Open a command line interface and type 'df -h'

This will display all the mounted drives in your system.

Mine displays the following.

foo@MyBoX:~$ df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/sda1             448G  308G  118G  73% /
none                  1.9G  768K  1.9G   1% /dev
none                  2.0G  2.2M  2.0G   1% /dev/shm
none                  2.0G  476K  2.0G   1% /var/run
none                  2.0G     0  2.0G   0% /var/lock
/dev/sdb1             459G   12G  424G   3% /mnt/work_files
/dev/mapper/udisks-luks-uuid-7cc81eaa-5df2-4005-984f-18304c43735b-uid1000
                      4.0G  2.1G  2.0G  52% /media/thumbdrive
/dev/sr0              231M  231M     0 100% /media/cdrom0

It shows my device as /dev/sr0. So I would use:

dd if=/dev/sr0 of=/home/foo/somedir/recovery.iso

I have used this many times to create CD and DVD backups. You can also mount the iso on a loopback file and use it as if it was a CD/DVD. Handy for games that run under wine or Crossover that require a play CD.