Does a hard disk store more data than what is reported as free space?

[wacky_dm]

Hi,

I filled a 2tb external drive is filled to the brim (i.e with only 50mb or so of free space remaining), then proceeded to delete around 10GB of data from the drive. Then I wrote back 10GB of different data on the drive, leaving around 50mb of free space again. 

However, running Recuva now shows me that it can recover multiple files (without overwritten clusters) that amount to more than 3-4gb! How is this possible? Since the previous data was overwritten by the new data, the old data shouldnt be recoverable, unless there is some extra free space that the hard disk doesnt show?

DM

[Augeas]

In a normal scan Rcuva doesn't look at the disk but gets data from the Master File Table. All files are listed in the MFT, and although the records flagged as deleted in the MFT are reusable it is common for there to be more files listed in the MFT than are on the disk. Foe example fill a disk with 1,000 files of 100 mb each, delete them, then fill it with 500 files of 200 mb each. The disk will be full but the MFT, and Recuva, will show 500 deleted files addressing 500 x 100 mb of data. I would expect the deleted files to have a state of overwritten, as there is no real free space available, but I don't know the exact circumstances that shows free space in your case.