In Linux computer, we have a simple tool to create CD or DVD .ISO file. This is very helpfull to backup your CD and DVD into ISO images:
To make an ISO from your CD/DVD, place the media in your drive but do not mount it. If it automounts, unmount it.
$ dd if=/dev/dvd of=mydvd.iso
$ dd if=/dev/cdrom of=mycd.iso
for scsi cdrom:
$ dd if=/dev/scd0 of=mycd.iso
And if you wanna make an ISO from files on your hard drive, create a directory which holds the files you want. Then use the mkisofs command.
mkisofs -o /tmp/mycd.iso /tmp/directory/
This results in a file called cd.iso in folder /tmp which contains all the files and directories in /tmp/directory/.
For more info, see the man pages for mkisofs, losetup, and dd, or see the CD-Writing-HOWTO at http://www.tldp.org. Enjoy Linux!!