Can someone tell me if the following statements are fact or fiction...
1) After you overwrite data, there still remains a "ghost" of the original image so when erasing data, you must overwrite the sectors multiple times to "really" erase the data.
2) A low level format makes sure that no data can ever be retrieved from a hard drive.
I am writing a hard drive purging software that simply opens every free block of a drive and will write all "0"s into them and then all "1"s into them. To clear the the TOC entries without having to reformat, I create a large number of empty files in a hierarchical tree structure and then I delete those files once done. Is this a waste of time?