I am aware of tools which write zeros or other useless data to fill up your harddrive, however so far all of the tools I have come across must fill up the entire harddrrive.
My understanding of the tools filling up the hard drive is so that when forensics attempt to recover, they only get the zero/useless data.
I am wondering if its possible to just fill up a part of the hard disk instead of the whole thing - This free space I want to fill was used space which contained my important files, so filling up only this part seems adequate.
I also have the problem that my OS files are on this same disk, so filling the whole disk with zero/useless data will cause me to lose my OS.
Does a tool exist? Is this a bad strategy?