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Data Storage Products Glossary

A, B, C, D, F, H, I, M, R, S, T, Y

Choose the first letter of the word from the list above to jump to the appropriate section of the glossary.

A

Areal Density

A measure of recording density calculated by multiplying bits per inch (bpi) by tracks per inch (tpi).

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B

Bit

The basic unit of storage for information in a computer system; a binary digit which can be either 0 or 1. Bits are represented by the presence or absence of changes in orientation of the magnetic domains along a track on the storage media.

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C 

Capacity

The amount of information, expressed in bytes that can be stored on a hard drive. Also known as storage capacity.

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D 

Defects

Irregularities inherent in thin-film magnetic layers that cause data to be recorded inaccurately. As track widths decrease, smaller defects can produce errors that would not otherwise cause on a wider track.

Disk Drive

The primary data storage device used by computers. Disk drives are used to record, store and retrieve digital information in a computer system.

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F

Format

To write a magnetic track pattern onto a disk surface, specifying the locations of the tracks and sectors. This information must exist on a disk before it can store data.

Form Factor

The industry standard that defines the physical and external dimensions of a particular device. Industry form factors are: 1.8", 2.5", 3.0", 3.5" and 5.25".

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H 

Hard Disk (HD)

A magnetically coated disk substrate, which spins inside a disk drive and is used as the storage medium for digital data.

Head

The tiny electromagnetic coil and metal pole used to create and read back magnetic patterns on the disk. Also known as a read/write head.

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I 

Inductive thin-film head

An electromechanical device that records (writes) on and retrieves (reads) data from the magnetic recording layer of the disk drive. Inductive heads read and write data using a conductive coil wrapped around a very small magnetic stylus.

Inductive thin-film media

Hard disks with recording surfaces optimized for use with inductive thin-film or ferrite recording heads.

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M 

Magneto-resistive (MR) head

Recording head that uses an inductive thin-film element to write data onto the media and a separate MR element to read the data.

Megabyte (MB)

One megabyte is approximately 1,000,000 bytes, capable of storing more than one million characters.

MR (magneto-resistive) head

Recording head that uses an inductive thin-film element to write data onto the media and a separate MR element to read the data.

MR (magneto-resistive) media

Hard disks with recording surfaces optimized for use with MR heads. MR media allows recording at higher areal densities than is typical for inductive media.

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R 

Read/Write head

Magnetic read/write heads are mounted on an actuator that resembles a record needle pickup arm and which positions the heads over the desired cylinder on the media.

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S 

Storage density

The compactness of data storage. Density is most commonly expressed by areal density (Mb/square inch) recorded on the surface of a single disk.

Substrate

The material underneath the magnetic coating of a disk. Common substrates include: aluminum or magnesium alloys for hard drives, glass for optical disks and Mylar for floppy disks.

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T 

Thin film

A type of coating allowing very thin layers of magnetic material used on hard disks and read/write heads. Hard disks with thin-film surfaces can store greater amounts of data.

Thin-film Head (TFH)

Currently, the most advanced type of magnetic recording head used to read and write information on disk drives. The two types of TFHs are inductive and the more advanced magneto-resistive.

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Y 

Yield

A measure of manufacturing efficiently; the percent of acceptable product obtained from a specific manufacturing process (es).

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