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To understand how perpendicular recording has changed hard disk storage and increased storage capacities, you first need to understand conventional, longitudinal recording.
Longitudinal Recording
As indicated by the name, longitudinal recording is a method of recording data to a hard disk drive (HDD) in such a way that (de telle sorte que)
the data bits are aligned horizontally in relation tothe drive's spinning platter, which is parallel to the surface of the disk. Essentially, you are recording on a magnetic material, where bits (a collection of magnetized particles) are laid out end-to-end (de bout en bout
). Longitudinal recording is the actual (reelles) method of how the bits are recorded on disk platters. The direction of this magnetic charge is horizontal to the media,meaning the north and south poles of the magnetized particles are lined parallel to the surface of the disk.
Longitudinal recording has been the standard method (méthode standard
) of recording for more than 50 years — the first commercial hard drive was introduced in 1956. Over the years we have seen many technological changes to longitudinal recording, which have resulted in higher-capacity drives.We've moved from 5.25 inch drives to 2.5 inch drives; the number of platters and heads have been reduced all the while increasing areal density (which is the amount of data per square inch of media).  With all of these changes however, the need to physically change the way data was written to the drive, was also being considered to reach (pour atteindre) higher storage capacities.
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Image Source: Hitachi Global Storage Technologies - Perpendicular Recording

Storage capacity with longitudinal recording was largely increased by decreasing the size of the magnetic grains thatmake-up data bits. As the magnetic grains became smaller, more data could then be stored on the disk. Unfortunately, magnetic grains have their limits. By continuing to shrink (à diminuer
) them, the point where data integrity would be compromised was on the horizon. This effect is called the superparamagnetic effect (effets).

Perpendicular Recording

Realizing the limits of packing smallermagnetic grains was heading towards occurrences of superparamagnetism, manufacturers still needed a way to pack more data onto each drive. Perpendicular recording differs from (diffère de) longitudinal recording in that data bits are aligned vertically (not horizontally) — or perpendicular to the disk, which allows for additional room on a disk to pack more data, thus, enabling higher recordingdensities. It is widely believed that with perpendicular recording, the superparamagnetism barrier can be pushed further back allowing for continued growth in the areal density of the media for some time.

Image Source: Hitachi Global Storage Technologies - Perpendicular Recording

Hitachi believes this recording technology, in time, can result in a 3.5-inch disk drive capable of storing anentire terabyte of data. Not only will perpendicular recording have an effect on desktop storage, but on consumer devices as well, which is a major driving force in storage sales. Smaller drives (1.8 inch), like those used in the popular Apple iPod will also grow in capacity .  in due time, we will see (en temps voulu, nous verrons)the iPod and similar devices offer 90GB of storage and higher.Alternatively (Alternativement), it could be used to produce much thinner and slimmer high capacity hard drives for consumer devices. Where you can store 4,000 on some of the higher-end MP3 players today; image being able to store 40,000 songs on one.
Perpendicular recording technology however will not start and stop with changing the way data bits are aligned. Much like the growth in capacity with...