Magnetic Storage
Tape Data Recovery - Magnetic Storage
Magnetic storage or magnetic recording refers to storage of data on a magnetized medium. Magnetic storage media, mainly hard disks, are used to store computer data as well as audio and video signals. The term ‘magnetic storage’ is commonly associated with computing, whereas ‘magnetic recording’ refers to storing of audio and video signals.
Technology
Magnetic storage is a non-volatile memory. It can preserve the information even when the power supply is cut. The method uses different patterns of magnetization in a magnetizable material to store data. Information is accessed using one or more read/write heads.
There are two types of storage media: sequential access memory or random access memory. However, hard disks and modern linear serpentine tape drives do not precisely belong to either category. They have several parallel tracks across the width of the media and the read/write heads take time to switch between tracks and to scan within tracks.
Types of Magnetic recording
There are three types of magnetic recording: analog recording, digital recording and magneto-optical recording.
In analog recording, the magnetic materials used are tapes which are initially demagnetized. The remnant magnetization of the material depends on applied fields. The writing head magnetizes the tape with current that is proportional to the signal. As a result, magnetization distribution is achieved along the magnetic tape.
Digital recording does not create magnetization distribution. Instead it uses two stable magnetic states, +M and –M, on the hysteresis loop. Examples of digital recording devices are floppy disks and HDDs.
Magneto-optical recording uses optical read/write methods. When writing, magnetic medium is heated locally using a laser. It is then magnetized using a small magnetic field. The reading process is based on magneto-optical Kerr effect. Example of magneto-optical medium is Minidisc developed by Sony.
