The term Magnetic Media covers a wide range of products from audio and video tapes to computer diskettes and hard drives. Magnetic media come in a wide range of sizes but they all perform basically the same way. The surface of the material used for magnetic data recording is coated with a magnetically sensitive coating that can be easily magnetized to store information. By magnetizing this coating in a specific binary pattern (i.e. A=0001, B=0010, etc.), data is stored magnetically and can be re-read or retrieved over and over.
Degaussing or Erasing Data from Magnetic Media:Degaussing is a process where the media is exposed to a magnetic field that is powerful enough to erase, or demagnetize, the media whereby leaving it in a magnetically blank (or zero) state and the data erased. Properly applied, degaussing renders any previously stored data on magnetic media unreadable by computer or in a diagnostic laboratory. Magnetic media has a property called Coercivity, which is measured in Oersteds, that tells you how hard or how easy each tape or hard drive is to erase or to ensure it is brought back to its blank or zero state. The technical unit that is used to measure and communicate the amount of coercivity (coercive magnetic force) that is required to ensure complete erasure of a given magnetic media is the Oersted. Due to variations in materials magnetic media is comprised of, the amount of coercive magnetic force (Coercivity) that is required to degauss/erase it varies. The current NSA requirement for erasure of hard drives is a coercive magnetic force of 5000 Oersteds for hard drives and 2800 Oersteds for magnetic tape. This is nothing more than the rating of the coercive magnetic field force required to completely degauss/erase the information stored on magnetic media available today. Typically, metal recording materials, found in hard drive platters, take a much stronger magnetic field to erase than magnetic tape media. A degausser’s magnetic field strength is usually rated/measured in gauss. The gauss rating of a degausser’s magnetic field strength is not a one to one rating with the Oersted rating of the media being degaussed. A degausser producing a magnetic field strength of 5000 gauss will not erase a hard drive with a coercivity rating of 5000 Oersteds. The ratio is approximately 3:1, meaning the gauss rating of the degausser must be approximately 3 times the Coercivity rating of the media to be able to degauss the media to NSA standards. Media with a coercivity rating of 5000 Oersteds requires a degausser with a magnetic field rating of approximately 15000 Gauss for proper erasure. All hard drives have information (magnetic servo patterns) prerecorded on them at the factory and this information is also erased as a result of the degaussing process. Therefore, the hard drive is not re-usable after degaussing due to the factory recorded information being erased. Technically, it would be possible to return the hard drive to the manufacturer and have this essential information re-recorded on the drive but it wouldn’t be very practical.
- 1. Magnetic media is constantly changing (higher hard drive densities) and the Oersted ratings are increasing.
- 2. Purchase a degausser with a higher Gauss rating (15000+ gauss). The higher the gauss rating the longer the degausser will be able to meet increasing Coercivity ratings and remain capable of meeting future NSA standards.
- 3. Electro Magnetic Pulse (EMP) degaussers are capable of producing a much higher magnetic field than permanent magnetic degaussers and will be capable of meeting future degausser requirements far after the permanent magnetic units go out of date.
Longitudinal (L) and Perpendicular (P) Recording MethodsLongitudinal recording technology has been the norm for recording data on magnetic disks for years but this technology had become limited in the amount of data that could be recorded on a hard drive platter. For the longitudinal recording method, think of the data bits as dominos laid end-to-end, horizontally around the surface of a disk platter as an example of longitudinal recording technology. This is the method/technology that has been used for years to store data on magnetic disk media. In 2005, Hitachi developed the perpendicular recording technology which significantly increased the amount of data that can be recorded on hard drives. Rather than the dominos (data bits) being laid end-to-end, they are standing on edge (vertically) which means a significantly higher amount of dominos, or data, can be stored in the same amount of space on the disk platter. The perpendicular recording method not only significantly increased the data capacity of hard drives but also significantly increased the life span of the magnetic hard drive as we know it today. Also, as depicted above, the perpendicular recording technology requires a thicker recording surface on the disk platter which requires a significantly stronger magnetic field to erase the data when the media is degaussed. The magnetic field of the degausser must penetrate deeper into the disk. This increase in magnetic field strength requirement is why some of the older degaussers are approved for longitudinal disks only … they do not produce the magnetic field strength to meet the Oersted rating of the newer perpendicular recorded disks. *Both longitudinal and perpendicular disks will be available for a few more years and then the norm will become perpendicular and the longitudinal disks will be phased out.
Recommended Degausser for High Security Magnetic Media Destruction
105 Hard Drive Degausser
- NSA approved for both tape and hard drives
- NSA approved as meeting 5000 Oersted (Oe) rating for hard drives and 2800 Oe for tape media (NSA EPL only shows degaussers as meeting the 5000/2800 Oe rating)
- Approximately 13,330 Oe
- 2.5 times existing hard drive maximum coercivity rating
- Will not become outdated anytime soon
- ill degauss magnetic media many years into the future
- NSA approved for both Longitudinal and Perpendicular recording method
- Accommodates multiple tape formats within 1” X 6” X 4.3” (DLT, etc.)
- Weight: 128 lbs (compared with competitor models at 420 lbs)
- Dimensions: 19”H X 10”W X 26”D (more compact than competitor models
- Power: 110V/220V
- Unit automatically recognizes 110V/220V power (No option/upgrade necessary for 220V (includes 220V/50Hz))
- 110V - 8 amps, 220V – 4 amps • Cycle time – 45 sec +/-
Benefits of the 105 HD Electromagnetic Pulse Degausser
- Permanent magnets are not as strong as electromagnetic pulse (EMP) degaussers.
- EMP degaussers produce a much stronger magnetic pulse
- Allows sanitization of higher capacity hard drives and tapes
- 105-HD EMP degausser will not become obsolete anytime soon as HD capacities increase
- As media capacities continue to increase to several Terabytes most permanent magnets will become outdated
- Current permanent magnet degausser manufacturers will not guarantee erasure of 3TB hard drives.
- 105-HD is engineered to last and guaranteed to erase 3TB drives
- Given magnetic field strength it can be extrapolated the 105-HD should erase up to 10TB drives
- Permanent magnets cannot come close to this
- Capacitors in 105-HD will not diminish
- Capacitor storage ability will not diminish, even slightly, until after 100,000 hard drives have been degaussed.
- Competitors try and claim permanent magnets last much longer but that is simply not true.
Minimal Training Required (Plug & Play)
- 1. Turn Power Switch on
- 2. Shortly the green “Degauss Ready” light will appear
- 3. Place hard drive into top opening
- 4. Press “Start” button
- 5. In approximately 45 seconds the degauss cycle will complete and the hard drive will release through the opening at the bottom front of the unit.
- 6. Remove media and repeat as required
- Minimal Training Required (Plug & Play)