Media written in an incompatible format must be degaussed before it can be written to by a Benchmark DLT1 tape drive. Simply erasing the media in its original tape drive is not the same as degaussing, as the format itself will still be resident on the media. It is critical to degauss DLTtape™IV media thoroughly to eliminate all residual data. Although media that is inadequately degaussed may still be accepted by the DLT1, residual data will likely cause poor performance and high error rates.

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.