Data Destroyer Disk Wipe is for wiping (a.k.a. purging) an entire hard disk (up to 20 GB in size), memory stick, floppy disk, etc., optionally with the exception of the top-level files and the files in selected top-level folders. It is a stand-alone version of the disk purge function contained in Hermetic Systems' program Data Destroyer.
To "purge" a file (on a disk or on any writeable magnetic medium) means to overwrite the data in the file many times (and then delete it) so that the data which was in the file cannot be recovered by any means. Several overwrites are required for security, since just one may leave electronic traces of the original data which can be detected by very sensitive equipment designed to do this.
If you wish to make sure that information which has been written to disk (such as financial data, company plans, proposals, etc.) can never be seen again after you remove it then you need a program with the capabilities of this one. Also, if you sell your old PC you may wish to make sure that all data is erased (permanently and irrecoverably) from the hard disk, including (for PCs running Windows 98) data in the swap file.
Beware of data removal programs that are claimed to delete files quickly. The only way data can be removed permanently is to overwrite it (on disk, not just in the disk cache) several times (not just once), and this takes time (more or less, depending on the speed of the hardware involved). Data Destroyer Disk Wipe provides an estimate of the time required to wipe a disk using a particular number of overwrites. If it seems that a particular disk wipe operation would take more time than is available, you can reduce the number of overwrites to be used, and thus the time for the disk wipe.