Data Destruction and Degaussing

A recent letter written by the United States Government Accounting Office states that resell of properly degaussed data tapes present a very low security risk. Click here to read this letter

There are typically two ways to make sure data on tape cannot be recovered. One is to degauss the media and the other is to re-write over the existing data, full length, and every bit position. Degaussing is a process that reverses the polarity of the magnetic particles. This process erases data and servo tracks, in the event the tapes being erased use servo track technology. Media products such as 3480, 3490e, DLT, SDLT can be degaussed and the media reused. However, 3590, LTO, 9840 and 9940 cartridges cannot be degaussed without destroying the servo track(s). For these media types Recertification requires data destruction using modern methods which do not destroy the servo tracks. See technical information below

Your media needs to go through degaussing or data eradication before disposal.
Do not just throw them away. Data should be destroyed for many reasons:

• Increase data security.
• Eliminate viruses and/or corrupt data
• Conform to privacy and storage laws
• Restore many types of media back to their original condition
• Improve recording performance
• Save money by recycling or reusing media
• Achieve tape drive and cartridge compatibility

Is my data SAFE??
All data is destroyed using cartridge and drive manufacturer approved processes prior to ever being read or written to. This insures the security and confidentiality of the data. Data Destruction Certificates and Confidentiality/Non-Disclosure Agreements are available at no charge. We guarantee the security and confidentiality of your data. We handle tens of thousands of pieces of media each month.
Conforming to new laws and regulations:
Degaussing magnetic media (specifically magnetic tape media) is the approved method of data destruction. Re-formatting your tapes is not good enough.

• Health Insurance Portability and Accountability Act (HIPAA)
• Sarnanes-Oxley Act (corporate reporting and auditing practices)
• Gramm-Leach-Bliley Act (Financial Services Modernization Act)
• USA Patriot Act (Bank Security Act)
• Homeland Security Information Sharing Act (Federal agencies security information)
• Other regulatory agencies concerned with Data Destruction (FDA,SEC,Utility Commission, etc.)

Why do most companies not degauss their own media?
MONEY! Most companies do not want the added cost of expensive equipment and additional labor costs to degauss their own media. By handling thousands of pieces each month, we are able to provide an easy and economical way for companies to reduce costs and increase their backup performance

Technical Information Regarding Data Destruction (For Tapes with Servo Tracks)

How we destroy data on 9840,9940, LTO, 3590 and other media with servo tracks

All of the above-mentioned tapes contain magnetic reference tracks which are pre-written by the media manufacturer. Without these servo tracks the tape drive cannot function correctly. Bulk erasing one of these data cartridges will erase all of the servo tracks, and make the cartridge completely unusable.

Erasing the data tracks, but not the servo tracks

The goal in erasing tape, therefore, is to eliminate the data, but not the servo tracks. To make the tracks on tape visible, liquids containing tiny magnetic particles can be used as highlighters. A small section of a tape is shown above. The checkered pattern servo track is surrounded by data tracks. There are several servo tracks on a tape, with the data tracks between the servo tracks. A correctly designed erase head erases all the data tracks but none of the servo tracks. The custom erase head in the MP-9940 covers the entire width of the tape and has small gaps where the servo tracks are located. All data tracks are erased in a single pass, but the servo tracks are left untouched. The picture below shows a section of an erased tape. After erasure all data tracks have been removed but the servo tracks remain.

Erasing the data entirely

Data recovery centers have become quite sophisticated. In many instances they are able to recover data that has been accidentally, or in some cases intentionally, overwritten or erased. Even when data have been erased to a point where the tape drive cannot recover it, a recovery center may still be able to read the tape data.

Most users want their “erased” data to be entirely unrecoverable. To test our ability to erase the data we wrote a constant signal on tape, one which is easy to detect during a subsequent read operation. The peak in the middle of the graph (below) is clearly visible, showing the constant signal that was written. The horizontal scale at the bottom of the graph shows this peak at 1*106 Hz, or at 1 MHz. The smaller peaks to the right at 2, 3, 4, and 5 MHz are harmonics of the first peak. The scale of the graph is logarithmic, so the peaks appear much smaller than they would be if they were shown on a linear scale.

Using the MP-9840 eraser, the test data are erased in a single pass in the same manner used to erase user data. Since a known signal was written, it is now possible to specifically search for this signal.

The read operation of the erased tape shows that the previously recorded test signal of 1 MHz is not detectable. The amplitude of several random noise peaks exceeds the amplitude of any signal at 1 MHz. This means that the data are entirely erased and not recoverable even with the most sophisticated methods. In fact, when reading a new tape that has never been recorded the results are identical to the above graph. A tape erased by the MP-9840 Eraser is indistinguishable from a new tape.

As good as new

It is important to erase the data with a high strength magnetic field, but this does not mean that this field should be as strong as possible. An overly strong or otherwise incorrect erase field can alter the characteristics of the tape. Sophisticated tape drives may still write on these tapes without reporting any write errors. However, the probability of a write or read failure increases with changes in the tape characteristics. Unless the failure rate is extremely high a data center may not even notice this increased failure rate. It would take a controlled and long-lasting test to detect a statistically relevant difference in the failure rates between new and erased tapes.

Any increase of the failure rate, however slight, is still undesirable. The erased tapes must carry the identical characteristics as new tapes. Fortunately there is a reliable method to guarantee that erased and new tapes are identical without having to test thousands of tapes: a signal with a constant frequency is written on tape. When the tape is read, the amplitude of this fundamental signal and the amplitudes of the harmonics of the signal are measured. The ratio of the amplitudes is known as “harmonic distortion.” A change in the harmonic distortion of the tape after erasing it would indicate a change of the tape characteristics, and therefore would imply a reduction in the quality of the erased tape.

The graph below shows a side-by-side comparison of the harmonics of a new tape and an erased tape. The amplitudes of the fundamental frequency and of the harmonics are identical, showing that the harmonic distortion remains unchanged.

Comparison between a new tape on the left and an erased tape on the right. The harmonic distortion for both tapes is identical, demonstrating that the erasure has not altered the characteristics of the tape

Erasing a tape involves more than distorting the recorded data in order to prevent a tape drive from recovering the data. We need to be sure that the data—and only the data—are entirely removed, leaving the servo tracks untouched. We also need to be confident that the tape characteristics remain unchanged by the erasing process. When done properly, no data should be recoverable from the erased tapes. The servo tracks should remain intact and the tape characteristics remain unchanged.

Technical Info About Degaussing (Erasing) Magnetic Media

Detailed technical information on how we degauss magnetic tape

An alternating current (AC) bulk eraser (degausser) is used for complete erasure of data and other signals on magnetic media. Degaussing is a process where magnetic media is exposed to a powerful alternating magnetic field. Degaussing removes any previously written data leaving the media in a magnetically randomized (blank) state.
The degausser must subject the media to an alternating magnetic field of sufficient intensity to saturate the media and then by slowly withdrawing or reducing the field the magnetic media is left in a magnetically neutral state. o erase recorded data it is necessary for the strength of the degaussing field to be greater in value than the coercivity of the magnetic media. Simply stated coercivity is the magnetic field strength rated in oersteds (Oe) required to change the magnetic orientation of the magnetic material. Check with knowledgeable dealers or degausser manufacturers to identify degausser models that meet your requirements. Examples of typical coercivities for computer magnetic tapes and disks are shown in table Below.

Data is typically not lost until its level has been decreased 65% to 75% (or more) below its original saturation recording signal level dependent upon the drive system.

A complete erasure level for most users is considered to be 60 dB below the original signal level – this of course depends on user requirements. A 60 dB signal decrease equates to reducing the signal to one tenth of one percent of its original value.

Magnetic media products that have factory prerecorded magnetic servo patterns should not be degaussed. Degaussing would erase the factory written magnetic servo signals and leave the media unusable. For all other magnetic media (without magnetic servo signals) after proper degaussing the quality of subsequent data recording should be unchanged or even improved.

It is very important to understand and follow the degausser’s operating instructions. This is especially important for manual units where the operator controls the media’s movement through the degaussing field. For higher coercivity media four passes are often recommended – two passes with a 90 degree rotation for the second pass and then repeat the process with the media turned upside-down. Of course these and other important operating considerations will vary with the type power and construction of the individual degausser models.

Information taken from the Quantum website:

The primary component of magnetic media that affects degaussing is “coercivity”. Coercivity is measured in ‘Oersteds’, and is the measure of how easily the media is magnetized, or de-magnetized. Media with higher coercivity ratings allow much higher data capacities, and require more magnetic energy to de-magnetize the media.

While most older magnetic media technologies have coercivity ratings of well below 750 Oersteds, and many of today’s technologies are rated up to 1500 Oersteds, DLTtape™IV media is rated at 1850 Oersteds. The degaussing equipment being used must have an Oersted rating at least equal to, and preferably two to three times greater than, the coercivity rating of the media being degaussed. For this reason, degaussing equipment that is designed for lower coercivity tapes, or was built before the new high coercivity tapes were introduced, can not be expected to degauss DLTtape™IV media effectively. Many manufacturers of degaussers do not specify the exact Oersted rating of their equipment. Rather, they specify what equipment to use for specific media types. Specific procedures for degaussing your media should be included with your degaussing equipment.

Information taken from the HP website:

Why will DLT1 not overwrite DLT 4000 format media unless I degauss the media?

DLT 4000 format written by DLT 4000/7000/8000 drives "saturates" the media magnetically more than the thin film/MR head used in DLT1. It is possible that in the course of overwriting, some of the residual DLT 4000 format will interfere with the new DLT1 format, causing higher error rates or inability to read the new DLT1 format. Degaussing is a process of "randomizing" the magnetic particles (or dipoles) that are embedded in the media formulation -- effectively restoring the media to a "virgin" state. Degaussing is also sometimes called bulk erasing. Erasing a tape is not the same as degaussing as the format itself will still be resident on the tape.