It appears that the storage space on my iPhone4S is not adding up to 16GB. I know 16GB is just the theoretical storage space, but currently, the total space seems too far away. Here's a screenshot of the storage status of my phone:
As you can see, 1.8 + 11.6 = 13.4GB. Where did the other 2GB go? Is this normal? Or are there residual files left on my iPhone that can't be cleaned up properly? I'm running out of space and so this means a lot to me.