Virtual CD-ROM under linux

for mount:

1. rm -fr /dev/cdrom
2. ln /dev/loop7 /dev/cdrom
3. losetup /dev/loop7 /iso/file/path/filename.iso
4. mount /dev/cdrom /media/cdrom

for umount:

1. umount /media/cdrom
2. losetup -d /dev/loop7