First make sure your second hard disk is connected to the system (plugged in, in case it is an USB one).
Then issue following command:
For instance here I get following output:
/dev/sda1: LABEL="RM-CM-)servM-CM-) au systM-CM-(me" UUID="9A185F24185EFF27" TYPE="ntfs"
/dev/sda2: UUID="78D46329D462E938" TYPE="ntfs"
/dev/sda5: UUID="97df7ada-41af-4a97-80e8-7d46eba3f099" TYPE="ext4"
/dev/sda6: UUID="1d717df8-c2db-45ee-9b2e-f06e55ef4f13" TYPE="swap"
/dev/sda3: UUID="ce9a87aa-1748-4e3a-ac3d-dc782cae358d" TYPE="ext4"
/dev/sdb1: UUID="ADC0-969D" TYPE="vfat" LABEL="USBSLACKINS"
Then use a text editor as root to append this line at the end of /etc/fstab:
UUID=ADC0-969D /media auto noauto,user,rw 0 0
Of course replace ADC0-969D
with the output of blkid you will get for /dev/sdb1.
After that you will be able to mount the drive with :
But probably your system will detect it when you plug it in then mount it automatically.
If instead it is always attached to your computer, just delete "noauto," so it be automatically mounted at start-up.
Last word: you can replace /media with any existing mount point if you prefer.