Perpendicular Recording

Perpendicular recording or perpendicular recording and perpendicular recording, also Perpendicular Magnetic Recording (PMR ) is a write process in magnetic disks. The effect was demonstrated in 1976 by ​​Professor Shun -ichi Iwasaki at Tohoku Institute of Technology in Japan at Tohoku University in Japan and 2005, first used commercially. At least since 2010 PMR represents the state of the hard disk technology.

Operation

In perpendicular recording, the magnetic moments are, each representing one logic bit, together with the used logical write process as PRML, not parallel to the surface of the data carrier ( longitudinal), but perpendicular thereto ( perpendicular ). Put it bluntly, the data will to some extent in depth. This results in a potentially much higher data density ( about three times as resistant); with the same surface so can accommodate more data.

Wherein the disks previously prevailing longitudinal recording technique allowed a maximum density of data 15 to 30 gigabits per square centimeter. It is limited by the superparamagnetic effect, which means that adjacent bits due to the proximity to adjacent bits change their magnetization ( data loss). Perpendicular recording allows, however, a data density of up to one terabit per square inch ( 155 gigabits per square centimeter).

The disadvantage is that the smaller white districts also have a shorter distance between the read-write head and the magnetic surface condition in order to write the data still and read. Therefore, this recording technique is technically more difficult to implement. The hard disk capacity can by this new recording equipment to the max. Tenfold increase. In addition, an increase in the read-write speed is the significantly higher density of data is reached, as the read head per turn read more data at the same number of revolutions, and thus the data rate increases. The method is now being applied in a modified form in the magnetic path and angle measuring systems to improve the measurement accuracy.

History

Floppy disks with extended recording density (English Extended Density (ED ) ), this recording method is used since the introduction in 1991 to put on a 3.5 "disk has a capacity of 2.88 MB ( FAT12 formatted ) or 4 MB ( unformatted ) accommodate, which is double the capacity of an ordinary, with longitudinal recording recordable, HD -3, 5 "floppy Selbiger size. However, further distribution did not find this disk.

In August 2005, Toshiba has delivered the first hard drive manufacturer a hard drive for the end user with this technique. This first published type is a 1.8 " hard drive with a storage capacity of 40 GB and a rotational speed of 4200 revolutions per minute.

In April 2006, Seagate has announced 7200.10 (750 GB ) and cheetah ( 15,000 min -1 and max. 300GB server drives) to use with the series Barracuda 15K.5 the new TMR heads, the read signal stronger than conventional GMR heads. provide