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.

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.
References in periodicals archive ?
For the past several years, areal density demonstrations have grown in excess of 100 percent per year.
It is likely that the rate of increase for magnetic disk areal density will start to drop below historical rates annually, due to the greater difficulty in making the new technology work.
In its Corporate Research labs last year, Sony provided the first demonstration of a breakthrough in tape storage areal density by achieving 6.
It has an areal density of 30Gbit per square inch, and a low power consumption level of 11 watts.
They adopted it for their own needs in order to increase the areal density of their digital tape media.
Engineers at companies like IBM continue to increase the areal density (the amount of data that can be stored in a given amount of physical space) of magnetic platters to the point where projections indicate a few dollars per gigabyte in several years.
5-inch drives, offering areal density for computers.