Data Destroyer

Introduction

It is well-known that when Windows "deletes" a file it does not actually destroy the contents of the file but rather simply unlinks the file from the file directory system, leaving the contents of the file in the disk sectors. This data will remain there until the operating system re-uses those sectors when writing new data. Until the old data is overwritten (and this may take months or longer) it can be recovered by programs that read disk sectors directly, such as forensic software (so called because it is used to obtain evidence in criminal investigations and also in legal discovery).

James M. Rosenbaum argued, in "In Defense of the Delete Key", "that information which its author has attempted to delete should not be (as it is now) admissible as evidence against that person if that information is subsequently recovered." This argument has not been universally accepted.

In order to be sure that a deleted file really is deleted, gone for good, its contents never to be seen again, it is necessary to overwrite the data sectors of that file. This is what Data Destroyer does. It purges data in files, where "purge" means to destroy, to eliminate completely by overwriting, so that the data cannot be recovered by any means. Data Destroyer allows you to destroy the contents of a file by overwriting it several times (or many times) with random bytes, and with bytes with alternating bit patterns, before the file is deleted (i.e., unlinked).

Data Destroyer can purge:

a single file all files in a folder all files in a folder and all files in its subfolders a specified subset of files in a folder and (optionally) in its subfolders all files (as above) whose file dates are before a specified date all files in selected subfolders (or in selected subfolders of a folder)

When a file is purged the slack area is also purged. (The slack area is the space on the disk, if any, in the final cluster of sectors which follows the end of the contents of the file. This might contain data from a previous version of the file.)

This software checks for possible errors in user input, and is designed to minimize the chance of accidentally purging a file that you wish to keep. It is even possible, in a multiple-file purge operation, to confirm the operation on each file before it is purged.

Another feature of Data Destroyer is that you can get an estimate of the time required to perform a purge operation. Secure deletion of many files may require some hours, and if you did not have an estimate of the time needed before beginning the operation you might get worried, not knowing how long it still has to run.

Data Destroyer erases data from any writable magnetic storage medium, which includes hard drives, floppy disks, ZIP drive disks and memory sticks. It is not suitable for erasing data on CD-ROMs (unless writable). The program erases specified files only, and cannot be used to wipe an entire hard disk.

Next: Types of purge
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