Too much information

Illustration by Loguy
Date:1 February 2010

Designers come up with new ways to soup-up disc drives to face the coming data crunch.
By Tyghe Trimble

Hard drives could reach their limits by 2015 unless researchers can find new ways to cram more information on to their disks. These drives use electrical pulses to create magnetic patterns on grains stored in rings on discs; when the discs spin, a scanner reads the patterns of electrical resistivity to retrieve the information.

The storage capacity of the hard drive has risen from less than 0,1 gigabits (Gb) per square inch to over 100 Gb per square inch (6,45 cm²) today. One breakthrough is “perpendicular recording”, which adds a bottom layer of magnetically weaker material to the disc, allowing it to store extra information. However, consumers’ need for more space to store videos, commercial information and experimental data is outpacing hard-drive development, so designers are seeking new ways to satisfy this growing appetite.

Three ways to deepen disc drive storage
Laser enhanced

¨ Heat-assisted magnetic recording uses a laser to heat a nanometre-size region on the disc at the moment when it is writing information. The heat enables the disc to cleanly store more information, and rapid cooling stabilises the written data and reduces interference later.

Two-dimensional rings
¨ Discs currently store data in independent concentric tracks, wasting some space. Designers are looking for ways to overlap the rings and still read data. If the read/write head could identify patterns when adjacent tracks interact, and pluck the correct data from the interaction, the storage potential of a disc would be increased.

Bit-patterning
¨ Magnetic grains could be stored in some organised way, such as in a series of 10-nanometre-wide magnetic islands etched into a disc by an electron beam. This would allow a much greater volume of information to be stored.

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