Use the mount and umount commands.
This example mounts a CD drive:
# mount -r -t iso9660 /dev/scd0 /cdrom
-r means read-only; -t iso9660 is the filesystem type. /dev/scd0 is the name the kernel assigns to the device. /cdrom is the directory in which it is mounted. The /cdrom directory must already be present before you try to mount the disk.
To find the filesystem type, use the file command:
$ file - < /dev/scd0
/dev/stdin: ISO 9660 CD-ROM filesystem data 'Data1
You can omit the -r (read-only) flag when mounting a CD-ROM. It will complain, but it'll mount the disk anyway:
# mount -t iso9660 /dev/scd0 /cdrom
mount: block device /dev/scd0 is write-protected, mounting read-only
This mounts a floppy disk readable/writable:
# mount -w /dev/fd0 /floppy
The following command mounts a USB storage device. The noatime option should be used on rewritable media that have a limited number of rewrites, such as CD/DVD-RW and flash storage devices:
# mount -w -o noatime /dev/sda1 /memstick
To unmount the device, use:
# umount /memstick