First of all your /dev/sdb isn't partitioned. I am assuming this is the disk you want to mount.

WARNING: THIS WILL DESTROY ANY DATA ON YOUR TARGET DISK

Run sudo fdisk /dev/sdb

1. Press O and press Enter (creates a new table)

2. Press N and press Enter (creates a new partition)

3. Press P and press Enter (makes a primary partition)

4. Then press 1 and press Enter (creates it as the 1st partition)

5. Finally, press W (this will write any changes to disk)

Okay now you have a partition, now you need a filesystem.

6. Run sudo mkfs.ext4 /dev/sdb1

7. Now you can add it to fstab

   You need to add it to /etc/fstab use your favourite text editor

   Be careful with this file as it can quite easily cause your system not to boot.

   Add a line for the drive, the format would look like this.

   This assumes the partition is formatted as ext4 as per mkfs above

   #device        mountpoint             fstype    options  dump   fsck
   
   /dev/sdb1    /home/yourname/mydata    ext4    defaults    0    1
   

Then on the next reboot it will auto mount.

This web page has a lot of useful info on fstab

The GUI solution for me is gnome-disks

sudo gnome-disks

Then with the configuration button you can "edit mount options", feel free to give the destination of your mount point and it will be saved into the /etc/fstab automatically

Note: the nofail option that causes the system not to hang if this mount point is not available, could be useful in case of potential unreachable filesystem on boot such as USB, NFS, etc.

To set the drive to mount automatically each time you boot the computer

You’ll need to edit /etc/fstab:

Just press Ctrl+Alt+T on your keyboard to open Terminal. When it opens, run the command below.

gksudo gedit /etc/fstab

Add this line to the end:

/dev/sdaX /media/mydata ext4 defaults 0 0

Note: Make sure to replace the X with the right value for your situation.

Or you can use Storage Device Manager, from the software centre.

The fstab file lets the system know which drives to mount (or how to mount them, at least).

sudo edit /etc/fstab

then add a line like this one:

/dev/sdb1      /mydata   ext4   defaults   0   0

Of course, replace the values to suit your actual locations:

• /dev/sdb1 should be the device and partition for the disk you want to mount.
• /mydata is the place where you want to mount it.
• ext4 is the type of filesystem it's using. If you're not sure, issue the mount command without arguments when the drive is mounted (even if you mounted it manually), it will tell you the filesystem type. (in 12.04 you may simply type auto which determines the filesystem for you at launch)
• The other values (defaults 0 0) are OK like I show them.

If you want to learn more, you can read man fstab.

You could do it via /etc/fstab.

For example, if you add

/dev/hda2   /myfiles    ext2    defaults    0    0

It means that the device/partition located at /dev/hda2 will be mounted to /myfiles using the file system ext2, with default mount options and no dumping and no error-checking enabled.

If you are using FAT32 or NTFS file system using the following:

For NTFS:

/dev/sda3   /media/entertainment    ntfs-3g rw,auto,user,fmask=0111,dmask=0000,noatime,nodiratime   0   0
/dev/sda4   /media/other    ntfs-3g rw,auto,user,fmask=0111,dmask=0000,noatime,nodiratime   0   0

noatime and nodiratime are some optimizations. If you want you can remove them.

For FAT32 replace ntfs-3g with vfat.

fstab will help you for sure.

For those lazy and cautious ones who want to use a simple and self-explanatory GUI there is a tool called Storage Device Manager (pysdm). The tutorial here will do basically the same as other answers in this thread suggest to do, but the tool will accomplish it with a couple of clicks and no need to enter configurations manually into fstab config file.

sudo apt-get install pysdm(Ubuntu) or sudo yum install pysdm(Fedora)

Nothing should go wrong, but just in case, backup the fstab conf: sudo cp /etc/fstab /etc/fstab.old

Now run the Storage Device Manager and select your preferred partition, click "Assistant":

PySDM assistant settings for automounting EXT4 partition:

PySDM assistant for automounting NTFS partition:

Reboot and see that your drive gets automatically mounted now.

You can learn more about assistant settings from this article, as it explains the process in details and my answer is based on it.

UPDATE: pysdm has been removed from the Ubuntu archives (AskUbuntu page), sudo apt-get install pysdm does not work anymore.

Avoid using pysdm for now.

It's been removed from the Ubuntu archives for a reason:

please remove Pysdm from Ubuntu repositories. It is obsolete (not updated since June 2006 !!), buggy (https://bugs.launchpad.net/ubuntu/+source/pysdm) , doesn't handle UUIDs (which is now fstab standard in all supported Ubuntu versions !!!) and it has already been removed from Debian repositories.

If you do not want to partition or cannot afford to, you can use udisks to mount or unmount devices or disks. The UUID method is the most stable one as other ID methods can change if you rename your label for example.

udisks --mount /dev/sdb
udisks --mount /dev/disk/by-uuid/70439c63-de2c-4319-a832-0dee5ea05fc5
udisks --mount /dev/disk/by-label/HDD

It will in fact do the same as you would do by clicking the device on nautilus.

Just add it as a "startup application" to preform at login.

To unmount, (if you need to):

udisks --unmount /dev/sdb

Will do the same as clicking the unmount arrow in nautilus.

One disadvantage over the fstab method is the device will be mounted in /media/disk_label with no option to choose another mount-point.

One advantage is you do not need root access to mount or unmount the drive.

More info over different methods of auto-mounting : AutomaticallyMountPartitions