Modern Linux distributions use udev which automount partitions to the system. This is most notably seen with usb device that are the predominant hot swappable media. Internal hard drives, particularly drives that are used to boot the system, have their mount points defined in the fstab file. Fstab is automatically generated during the Debian/Ubuntu installation process. Occasionally you’ll want to add entries such as to automount samba shares or if you have Windows partitions on the hard drive; although Windows partitions will most likely be handled automatically by udev. You can mount iso images automatically using fstab; but this may be unnecessarily permanent, and a temporary
mount -t iso9660 cd.iso might simply be easier and more convenient.