Perpendicular Recording
Hard Drive Recovery - Perpendicular Recording
Perpendicular recording or perpendicular magnetic recording (PMR) refers to a technology for data recording on hard disks. PMR technology is capable of delivering more than triple the storage density of traditional longitudinal recording. Currently PMR is mostly used in hard drives.
Technology
Perpendicular recording enables higher storage densities by aligning the poles of the magnetic elements. The main advantage of this technology is that it can retain the magnetization of the medium despite thermal fluctuations caused by the super paramagnetic limit. This is because perpendicular recording uses higher coercivity material, as the head’s write field penetrates the medium more efficiently in the perpendicular geometry. A higher coercivity medium is inherently thermally more stable, as stability is proportional to the product of bit volume times the uniaxial anisotropy constant Ku, which in turn is higher for a material with a higher magnetic coercivity.
Popular Examples
Some of the popular examples of perpendicular recording devices are the Cheetah 15K.5 (up to 300 GB) and Barracuda 7200.10 (750 GB) from Seagate Technology; 20 GB Microdrive from Hitachi; a 200-GB hard drive from Toshiba, announced in June 2006; and WD Scorpio 2.5-inch (64 mm) hard drives from Western Digital. Several new products are also being introduced by major players.
Current hard disk technology with longitudinal recording has an estimated limit of 100 to 200 gigabit per square inch. This estimate is constantly changing, however. Perpendicular recording is predicted to allow information densities of up to around 1 Tbit/sq. inch. It is estimated that perpendicular writing technology will reach its limits and newer technologies such as HAMR or Patterned media recording will be required as alternate methods.
