• November 24, 2008

What is a Degausser?

Customers are always asking us: what is a degausser and do we need to use hard drive degaussing service?

Well, first let's start by explaining what a degausser is.  Basically, a degausser is a machine that changes the magnetic domain of magnetic data storage devices.  The magnetic domain is where the data is stored.   Examples of magnetic storage would be things like backup LTO and DLT tapes, VHS tapes, cassettes, reel to reel tapes and all types of hard drives. Compact Discs (CDs) are not magnetic storage because the data is stored on the disc with optics.   When the degausser is applied to these magnetic domains they are scrambled into random patterns.  This process renders the data that was stored in these magnetic domains unreadable.

Some generic magnetic storage devices can be reused after the degaussing process has taken place.  Reel-to-reel tape and VHS video cassettes and older media types are examples of these.  However these items are so old that saving them or reusing them is generally not a common practice because of the very limited storage capabilities.

For other forms of newer data storage like computer, laptop and server hard drives and some backup tapes degaussing renders the media completely unusable because of permanent damage to the storage system.  This happens because of damage to the special servo control data that is written onto the media at the factory by the manufacture.  Once the servo track is damaged, it can not be corrected.  Degaussing removes not only the stored data on the device but also removes the servo control data, and without the servo data the device is no longer able to determine where data is to be read or written on the magnetic media.

Here is a few definitions that you might hear if you are talking about a degausser:

Oersted - A unit of magnetic intensity equal to the intensity of a magnetic field in a vacuum.  How does that apply to a degausser? Oersted is a measurement applied to magnetic media. Most of "today's" tapes have an energy level rating of 1800 oersted or higher.  Hard drives can have an oersted rating up to 5000, which is the most powerful degausser in the commercial market.

Coercivity - The amount of applied magnetic field (of opposite polarity) required to reduce magnetic induction to zero.  How does that apply to a degausser? This is the ease (or difficulty) by which magnetic media can be demagnetized. A tape with an oersted rating of 1800 might also be called a high coercivity tape.

Something to think about is Oersted and Coercivity are often used interchangeably, which only makes things more confusing. Just remember that the newer the technology, the higher the oersteds needed to erase the item.

OK, now that you know all of the fun technical stuff regarding how a degausser works, let's talk about why anyone would ever need to use one.  Most of the time, it is because of a federal law that needs to be followed.    This usually applies to clearance level information like Classified or Top Secret.  In an attempt to protect the country's information, several different federal agencies have standards and procedures that have been written on how to handle the destruction of sensitive data.  Those standards involve the use of a degausser and then physical destruction of the unit.

OK, so why?  Well, some people do not understand that just destruction of the storage device technically does not remove the data. It just makes the device (tape or hard drive) unusable.  This means that even though the item has passed through a shredder, it still has data on the little pieces that can be recovered   We have read on many of our competitor's websites that after shredding the material was not recoverable which would be true, in some cases, depending on where the shredded hard drive was sent.  After shredding a hard drive, I strongly doubt that the guys at Geek Squad would not be able to retrieve the information.  However there are places that even the smallest pieces of shredded hard drive can be sent for data retrieval.  How is this possible?  Because the hard drives or tapes store the data using magnetics.  If you take a magnet and smash it on the ground, the magnet will break into the small pieces.  Each of these pieces is still magnetic and storage works the same.

With that said, most companies or organizations do not need to use hard drive degaussing for their data destruction needs.  Let me repeat what I said, most companies, organizations, and government agencies do not need to utilize a degausser.  This is because shredding is a perfectly fine application for destruction.  When you only have a handful of places that the shredded data can go for recovery, the idea of someone taking the shredded material and recovering it is a long-shot. If the data on the storage devices is classified, then the company or agency does not have any choice. They must use a degausser before the physical destruction takes place.  Another factor is that adding the degaussing service doubles the cost of the destruction process.

PC Recycler utilizes two types of degaussers to handle all types of media.  We can provide hard drive degaussing service on-site at your office or off-site at one of our facilities.

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