areal density


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areal density

[‚er·ē·əl ′den·səd·ē]
(computer science)
The amount of data that can be stored on a unit area of the surface of a hard disk, floppy disk, or other storage device.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

areal density

The number of bits per square inch of storage surface. It typically refers to magnetic disk and tape, where the number of bits per inch (bpi) times the number of tracks per inch (tpi) yields the areal density.

Magnetic Disk - From 2K to 1T and Beyond
The areal density of disk storage has increased dramatically since IBM introduced the RAMAC hard disk computer in 1956. RAMAC had an areal density of two thousand bits per square inch, while current-day disks have reached and exceeded one terabit per square inch.

Magnetic Tape - From 6.7 to 201 Gb
Magnetic tape density increased by a factor of 30 in slightly more than a decade. In 2006, IBM debuted magnetic tape with a bit density of 6.7 gigabits per square inch (GbSI). In 2017, IBM and Sony introduced "sputtered media" tape with a density of 201 GbSI, resulting in a tape cartrdige that holds more than 300 terabytes. The sputtered media means that the magnetic particles on the tape are a fraction of the size of previous particles. See perpendicular recording, superparamagnetic limit, holographic storage and AFM.
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References in periodicals archive ?
Among its products we find a Level 2 solution with 58-59 mm thickness and an areal density of 125-130 kg/m2, and aLevel 3 with corresponding data of 79-80 mm and 157-162 kg/m2, both for standard temperature operations.
The areal density of copolymers (I) for HDPE*/PA6 microlayered samples determined by XPS.
The exact areal density at which the superparamagnetic effect occurs has been a moving target, subject to much scientific and engineering debate.
Toshiba achieved the world's first 100GB 2.5-inch HDD by establishing a new benchmark for areal density: 80-gigabits of data per square inch.
Implementation of new approaches in conventional MO recording shows promise in boosting areal density 10-fold.
These applications require ever-increasing amounts of storage capacity, giving rise to more narrow track pitches and smaller features to increase areal density, and the use of multidisc stacks to increase density within the same footprint.
Semiconductor memory chip density was used for processors, and the recording, or areal density, was used for disk drives.
In this regard, applying metallic meshes was found to be beneficial because of their low areal density. Fragmentation of centimeter-size hypervelocity projectiles on stand-alone metallic meshes was experimentally studied in [5, 6].
After in situ polymerization of PANI, the areal density of fibrous mat was increased from 0.140 mg [cm.sup.-2] to 0.144 mg [cm.sup.-2].
The drive has a greater areal density that offers 33% more capacity in the same 3.5-inch form factor at 24% lower watts-per-gigabyte than its predecessor.