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 ?
Table 2 gives the influence of the dimple central included angle on piston service life when the dimple area density was the same by taking the L-D2 area density as a criterion.
Densities were standardized by air space and interstitial area density as [[A.sub.A](Air)] and [[A.sub.A](int)], respectively [28].
Instead, we use the "more general notion" of interfacial area density [3].
Five sections of one tissue were randomly inspected 400 times, and the computer color magic image analysis system (CMIAS) was used to quantitatively analyze the expression of CSE and SUR-2 proteins by measuring the area density (area density = area of positive hits/total area x 100) (21).
The leaf area density was assumed from the values obtained by Tota et al.
The first row of each column in the table of area densitometry revealed the average area density (intensity) (mean AD) in all six selected segments of rotating scanned Scheimpflug images, as shown in Figure 2, and were obtained with the threshold set at 0%.
The calculated average oil film thickness mentioned in this paper for textured surface area is the average separation for the two components: average separation for the textured part of the surface times the texturing area density combined with the average separation for the plateau (nontextured) part of the surface times the plateau area density.
By analyzing a series of depletion scenarios (see below) the central tendency ([[bar.X].sub.1]) of the efficiency of fishing nets for each studied species was calculated and used in the swept area density calculations.
Tenders are invited for Wire Bpvlz 70 Mmsq Ty-16-505-911-76 Braid Surface Area Density Above 95%
Agglomeration effects are observed in all four countries, but they were noticeably stronger in India and strongest in China, especially with regard to area density. Human capital is strongly associated with earnings in all four countries.
To assess the microvessel density, highly vascularised foci ('hot spots') after immuno-staining with CD34 were quantified for number of vessels per square millimetre and for vascular surface area density.
Leaf area index (LAI) and Leaf area density (LAD) is an indicator used to study the thermal conversion of the trees with its environment [13].

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