Data destruction

Data in IT is considered to be a series of zeros and ones that are read by some technological process from the media  on which they placed. Depending on the way the data is stored, media can be   magnetic, optical, magneto-optical and electronic (mechanical are out of use nearly half a century).

Currently, the most popular devices for storing data are magnetic media - media that stores the data using different polarization of the magnetic data carrier. These types of media include hard drives, as the most common media, magnetic tapes and floppy disks. To fully understand what it means to delete data, and then the destruction of data, it is necessary to know how the data is stored on the medium.

Every magnetic medium consists of many magnetic "locations" - programmable units. These units are called magnetic dipoles. Electrical magnetic field produced by the writer (within hard drives popularly known as "the head") polarizes the range of magnetic locations. When the effect of magnetic field stops, programmable material retains its polarization which allows us to read that information again. If you wish to delete the order of magnetization - polarity of the dipole (which, in fact, is the data), we need to re-polarize the same magnetic units to other accidental or intentional order.

Magnetic locations are grouped into sectors that are the most commonly measured in MB or GB. Operating system manages the content of the magnetic locations. Algorithm that is used to write a content varies from one to another operating system - from one to another file system.  File system usually refers to the way the hard disk space is organized and the way in which the data is getting written on the disk. The operating system must know both this informations so it could even have an ability to read and write the data (organized in files). Manipulating the files, finding files on the disk and its content are the main tasks of the file system.

According to the above, it would be logical that when we delete the file, we delete the whole content (adress of the file and its contents). However, deletion would then last just as long as the writing. What we can conclude is that with the simple deletion of files, we delete just its adress but not the content itself. That content can be easily found later using the software that is available to everyone and represents no secret even for unskilled people.

Permanent deletion of data is possible to achieve in two ways:

1. By writing the new data over the existing locations (which isn't possible when the disk is damaged)

2. By demagnetization

Demagnetization is the process of data deletion using a strong magnetic field and it is used when it's necessary to destroy the data irreversibly. It is particularily convenient when used on damaged hard drives on which it is impossible to access the data to delete it.

Demagnetization is possible in almost all modern devices for storing digital data on a computer that operate using magnetic media: hard disk drives of any size (ATA, SATA, SAS, SCSI drives size 1.8 ", 2.5", 3.5 "), magnetic tapes (LTA, DLT)...

Why would you need a permanent data deletion?

• When some sensitive data is no longer needed, it must be protected from any attempt of reading it. Simple deletion of files leaves the contents of the medium with open possibility of recovery and access to your confidential information and sensitive data.

• If, for some reason, you need to take your drive with confidential data to repair/complaint, and want to be sure that the data from it will not get into the wrong hands, degauser is the right solution. All your data will be irreversibly destroyed without losing the warranty on the drive (remember many examples of celebrities whose personal data have "suddenly" appeared in public, with devastating consequences).

Process of demagnetization

In the process of demagnetization, strong magnetic forces which affect the disk have a much greater intensity than the ones used by the disk itself to erase or write the data. These forces are strong enough to replace and nullify the previously entered information.

Characteristic hysteresis curve of ferromagnetism is S-shaped, which describes the magnetization of ferromagnetic materials under the influence of an external magnetic field. Curve has this shape due to the routing of magnetic domains. When such a material is exposed to a magnetic field, magnetic domains are getting more and more oriented towards the external magnetic field. By reducing the erasing magnetic field, intensity of magnetic flux in the medium is reduced to a negligible value.