In linux, in order to access a filesystem (being anything from cd, floppy, hard disk, etc.) you need to "mount" it so that you can access it from your root filesystem.
Different distributions use different "mount points" which are places in your root filesystem that you can access your other filesystems. If you are from the MS Windows world, think of it as a your "My Computer", from there you can go to your floppy drive, hard disk, cdrom, etc.
Examples of mount points can be "/mnt/cdrom", "/cdrom" "/media/cdrom", etc.
You can mount your cd in one of two ways. Most distributions automatically set up your mount points and add them to a file so that they are ready to go when you need them. The file used is "/etc/fstab" which holds all your mountable partitions. For a distribution like Mandrake, you can "mount" your cdrom by placing the cd into the drive and typing in a console "mount /mnt/cdrom". At that point, you should hear the cd start to spin up, and you can access the files on there by "cd /mnt/cdrom". When finished, you must un-mount the cd with "umount /mnt/cdrom".
If the entry does not exist in your /etc/fstab file, then you can mount a filesystem as follows:
QUOTE
mount -t <fstype> <device> <mount point>
for example:
mount -t iso9660 /dev/cdrom /mnt/cdrom
The bottom example shows how to manually mount your cdrom to the /mnt/cdrom mount point. For more information on mounting, type "man mount" in your console to read the man page.
Mandrake requires you to use the cd because it is configured by default to install all files from the cd