Data Recovery Digest

A degausser is a piece of equipment that uses electromagnetics to delete data from magnetic media, like hard drives or tape. It got its name from Johann Gauss, a mathematician who studied electromagnetic fields. The process is also referred to as erasure.
Degaussing permanently removes any data that is stored on a device. It does this by changing the magnetic alignment of areas on the device called magnetic domains. It causes these domains to become completely random in pattern, meaning it is unable to process any data that was once stored on the device. Formatting a device or simply deleting the data on it manually doesn’t get rid of it permanently. It is still stored in the device’s history and can be accessed again using data recovery tools. Degaussing is a permanent data removal solution.
There are different types of degaussers, each rated depending on its magnetic field strength. This is measured in Gauss or Oersteds (after Hans Christian Oersted, who discovered the magnetic property of electricity). Magnetic media has a property called coercivity, measured in Oersteds, which represents how easy it is for the device to be erased. For everything to be fully deleted, the degausser’s field strength must be two or three times the coercivity of the device.
Using a degausser is efficient because they have very low error rates. They can also help cut costs as certain media will be able to continually be reused. Magnetic media can be tricky to dispose of (burning is toxic and they aren’t biodegradable), so using the drive multiple times is beneficial for the environment.
Using a degausser can also help you comply with the law. Some countries have strict guidelines about how to handle confidential information and will penalise if the data isn’t treated with care. Binning a hard drive with data on it is illegal – the data can easily be accessed and it pollutes the environment. Companies cannot risk being financially penalised or damaging customer trust, thus proper handling of the data is essential. This is where a degausser comes in, offering an effective way to securely remove any data stored on a device.
Depending on the type of media, degaussing can cause permanent damage to the storage device. Old media like VHS tapes and floppy disks can be reused after the process. However, modern hard drives and some tape backups will be unusable. This is because the process damages the random read/write head mechanism. Something called servo data is written onto the drive during manufacturing using special hardware and these patterns aren’t meant to be overwritten. However, degaussing removes such data, meaning that only with manufacturer-specific hardware will you be able to make the drive functioning again.
A variety of different organisations use degaussers. For example, defence organisations can erase confidential information or television broadcasters can use it to allow their tapes to be reused. Due to the specialised nature of a degausser, they are usually only something you find in use in businesses rather than the home.