Pentagon Uses Rewrite Program To Protect Data--And Hard DrivesPentagon Uses Rewrite Program To Protect Data--And Hard Drives

The Department of Defense has developed new computer disposal procedures that require data-erasing software programs to overwrite secret data on computers that are going to be donated or sold. An agency employee secures the data, without destroying the hard drive, by overwriting it with a series of meaningless information in binary code patterns of "ones" and "zeros."

Using a rewrite program to mask data stored on the hard drive is much more effective than just deleting it, says Emily Geneva Finan, a technology project leader for BountySystems Inc., a managed service provider. Finan says a former BountySystems employee deleted several files and programs from his company-issued notebook computer after he quit his job. To recover the erased programs, BountySystems sent the hard drive to data recovery company Ontrack Data International Inc., and was able to retrieve some of the deleted documents. "If the employee had run a rewrite program, we wouldn't have been able to get anything back," says Finan.

While it is possible for data to exist on some parts of the hard drive even after using rewrite software, the physical make-up of disk drives makes it less likely to hold on to bits of data after a rewrite, says Jim Reinert, director of business development at Ontrack. "There might be remnants of data off to the side of the track in the disk drive, but the density and tolerance inside disk drives has become so small and tight, there's less chance of data being left on the drives," Reinert says.

Overwriting a hard drive once, as opposed to doing several rewrites, is sufficient to mask the data, Reinert says. But that may be true for some companies, but not when working on government projects. Nancy Bogart, a tech staffer with ITT Avionics, a government contractor, says her department overwrites government disk drives about eight times. "Using the right kind of technology, someone could read something on a disk several rewrites deep," Bogart says. "You have to decide how much of a risk it is for you not to overwrite. Someone with the right technology might be interested in that information," she adds.