Hard disk, unlike computer memory, is non volatile i.e. it stores the data even after the computer is switched off. That is why we use hard disk in our computer to store information and files. But sometimes it is required to delete a file from computer permanently so that no one can ever access that file. This is mainly the cause of concern when the file is of very important use and the computer is in public access. To stop the file from being accessed we often keep its backup over a personal storage medium like USB drive or CD ROM and copy it to the computer when required. And after the work is over we delete the file and think that it is gone permanently from the hard disk.
But in real case the files can be recovered even after it has been deleted from recycle bin using various data recovery software available in market. So, to keep the security you need to remove each and every trace of the existence of the file from the hard disk. This complex task can be done by using data eraser software. The data eraser wipe data from the hard disk completely and fill the traces of the existence of file with garbage value. Thus, even after using the file recovery software no one will be able to recover the file back. But use the wipe software carefully because if you delete a wrong file you cannot recover it back.
