Whenever I delete a large set of files (multiple GB) I noticed that this doesn't free space as much as I would expect. My expectation is that if I delete a certain amount of data my free space will go up with the same amount.
However, if I delete 5GB of files, empty the trash and look at the free space on my hard disk, it hasn't gone up with 5GB. This happens both on Windows XP and on Windows 7.
So what happens with the space that the deleted files were taking in? Why is there no one-to-one relation between the amount of data deleted and the amount of free space reclaimed?