As we know, a file usually takes more than one cluster on a drive. When recording a file, clusters connect in a chain, wherein each cluster indicates the number of the next, comprising the following portion of this file.
In order to delete file permanently, we need to rewrite the contents of all the chain of clusters storing a selected file.
Deleting files in the good old FAT32 is open for research, as well as the system itself. You can easily manage clusters and point system, which clusters we use to record, like Terminator eraser software does.
However, the commercial essence of Microsoft closed full access to NTFS file system, making it a kind of a black box for developers. The system has control inputs and outputs, but hides its structure and control options.
Erasing files in NTFS is not as easy as in FAT32, as we can’t tell the system what clusters we need to rewrite. Guided by the idea of the main developers, NTFS, is committed to store information on the drive as long as possible.
It will automatically overwrite the old clusters, which, of course, won’t help in the main task of removing files, i.e. making them securely deleted.
Of course, in some situations eraser software can act in a flawed, but workable way. It records main files on a blank drive, and then completes the entire free space on a drive with trash...
Now, in Quality Mode of Terminator eraser software clusters will be securely overwritten as needed. This will work if operational files weren’t modified or overwritten while being used.
It’s a weird way, anyhow.