I am pretty sure that when manufacturers post a certain size on a hard drive, it isn't completely accurate. They basically chop it off at the next round number. For instance, my hard drive on an old machine reads 30G on paper, but 27.7 effective. That is probably why you are getting the 114 on your drive.
As for the file explorer figure, you might be looking at a certain file system mount. Take a look at your fstab file and you will see the different mounts that you have, occupying space on each (that in theory will add up to your total hard drive space). To see capacity on all of them, type "df" at the command prompt.
Hope that helps.