Hard Drive Erasers

What Is a Hard Drive Eraser? How Do HD Erasers Work?

Many computer users believe that when they drag a file into the trash and then empty the trash on their desktop, that file has been deleted. In fact, the actual data itself has not been deleted – only the path to access that data. There are three ways in which to get rid of data on your computer hard drive: degaussing the hard drive, physically destroying the HD, or erasing the drive using a hard drive eraser.

Whereas degaussers erase magnetic media by resetting the magnetic charge of the hard drive to a neutral state, thus erasing the data, hard drive erasers employ software that overwrites the drive. Technically speaking, there is no actual “erasure” happening – however, if a drive is overwritten enough times, the underlying data will become indecipherable. The more times a drive is overwritten, the more difficult it becomes to forensically restore any of the original data from the drive.

Overwrite software generally overwrites a drive anywhere from one time, to three times, to up to 35 times. Depending upon the size of the drive and the number of overwrites configured, this process could take multiple hours or even days.

Because the HD eraser actually interfaces with the drive, hard drives must be functioning in order to be erased by an erasing unit. In addition, overwriting programs skip over any bad blocks on the drive.

What is Secure Erase? How Does Secure Erase Work?

Most ATA interface computer hard drives manufactured after 2001 with capacities greater than 15 GB come preinstalled with an NSA-compliant security erasure program called Secure Erase. The Secure Erase protocol was designed by the National Institutes of Standards and Technology (NIST) and provides top secret erasure of a computer hard drive to NSA specification.

Concerned about the threat of a virus that might trigger mass HD erasures, NIST specified that Secure Erase be installed on hard drives as a security measure but yet disabled for the average user. There are now hard drive erasers available that activate Secure Erase. Once enabled, the drive is erased to NSA specification (NIST 800-88 4 and 800-14). Secure Erase is compliant with the following laws: the Health Insurance Portability and Accountability Act (HIPAA), Gramm-Leach-Bliley Act (GLBA), Fair and Accurate Credit Transactions Act (FACTA), Federal Information Security Management Act (FISMA), Personal Information Protection and Electronic Documents Act (PIPEDA), and the Sarbanes-Oxley Act.

Many units will default to a Department of Defense secure overwrite program (5220.22-M) if a hard drive was not factory installed with Secure Erase. In addition, Secure Erase will overwrite even bad sectors of a hard drive, which most overwrite programs do not.

Do Hard Drive Erasers Work?

Hard drive erasers can provide total data security, but the quality of erasure and the level to which the information will be unrecoverable lies in how many times the software has overwritten the drive. If you are using a free software overwrite program that overwrites the drive only one time, then much of that information may actually be recoverable by a computer forensic data recovery specialist. However, if the drive has been completely overwritten eight times or more, as per Department of Defense specification, then it has been erased to government specification and the data is likely unrecoverable, even by a computer forensic expert.

Can I Erase and Reuse My Computer Hard Drive?

If you need to reuse your hard drive, erasing the drive before redeploying is the best way to go.

Hard drives come preinstalled with manufacturer-recorded servo tracks. If these servo tracks are erased, such as with degaussing, the HDD loses its ability to interface with the computer thus cannot be reused. Some examples of media with servo tracks are computer hard drives, LTO, Travan (ADR, SLR), AIT, Magstar 3590, and StorageTek 9840 and 9940.

A hard drive eraser will permit you to completely erase the recorded data from the media, but it does not erase the servo data, so you can reuse the drive, thus potentially saving your company thousands of dollars.

Does One Type of HD Eraser Work on All Hard Drives?

Many hard drive erasers interface either with IDE/SATA drives or SCSI drives but not both. In certain instances, one unit will provide adapters that will erase both IDE/SATA and SCSI drives. Machines that handle SAS drives will generally also erase IDE/SATA drives with adapters but not SCSI drives. Many erasers also handle laptop drives and Flash media with special adapters. Before purchasing or renting an eraser, be sure to get a unit capable of erasing all of your media, including the proper adapters.

How Long Does It Take To Erase a Hard Drive?

A hard drive eraser overwrites the entire hard drive multiple times. Thus, the larger the drive, the longer the overwrite process will take. It is much faster to erase a 50GB HDD than a 500GB HDD.

Secure Erase utilizes a low frequency one-pass overwrite and is thus much faster and more secure than simple overwrite software.

How Do I Erase a Solid State Hard Drive (SSHD)?

Several types of newer hard drives employ solid state memory as opposed to a disk. Solid state drives cannot be degaussed because they are not magnetic media. A one-pass secure overwrite is recommended for a SSHD, such as Secure Erase. However, the best way to be assured of security erasure of a solid state drive is to physically destroy the drive using an industrial shredder.

Looking To Rent Hard Drive Erasers?

Many different types of hard drive erasers are available not only for rental for weekly or monthly periods, but also available for purchase used.