Attaching devices under GNU/Linux. Basically, any removable medium is accessible under a directory in the filesystem.
By convention, /mnt is used as the usual “mount point” (i.e. the point where stuff gets attached to the filesystem) for removable devices like floppy and CD/DVD drives.
So, in most systems, a CD's contents can be found under /mnt/cdrom. A floppy is usually mounted under /mnt/floppy