Degausser Information - Glossary

Below is a list of degausser / taper erasers terms.

1f: The lower operating frequency of a rotaing memory device. In a single density systems it corresponds to all clock and not data bits.

2f: The higher operating frequency of a rotaing memory device. In a double density systems it corresponds to clock and data bits in each bit cell.

Betacam: 1/2" tape format

Beta SP: Video tape format

Bit: As applied in magnetic recording, it represnts one recorded information cell ("bit" is a contraction of "Binary" and "Digit" to define a unit of information).

Bit density: Bits per unit length, are or volume of the recording medium; for example, the number of bits per square centimetre of magnetic tape.

Bit error rate (BER): The fraction of bits that are in error. BER = e/N where e is the number of errors and N is the total number of bits (corect bits plus erroneous bits).

Bit: shift Also called peak shift. A shift in the detected signal peak caused by the influence of a neighbouring flux transition.

BPS: Bits per second

Bulk eraser: a device for the erasure of recorded signals on magnetic media. A strong alternating magnetic field is used to remove the signal. Also known as a degausser.

Certification: The process during manufacture of detecting and removing from the diskette defects which may couse data errors.

Coercitivity: The strength with which magentic particles resist change. The amount of applied magnetic field (of opposite polarity) required to reduce magnetic induction to zero. The ease (or difficulty) by which magnetic media can be demagnetized. A tape with an oersted rating of 1800 might also be called a high coersivity tape.

Coercivity or Coercive Force: The field strength required to bring the flux density to zero in a magnetic material

Computer Reel: magnetic tape wound on a real; used to store computer data

Cookie: the coated circular diskette thyat has been punshed to its final shape, but has not been sealed in its jacket.

D1, D2: Digital Video Master Cassettes

DAT: Digital Audio Tape

dB: decibel

DCRS: Digital cassettes

Decibel: A dimensionless unit for expressing the ratio of two powers, or more usually voltages or currents, on a loge=arithmic scale. If A and B represents two voltages or currents the ratio A/B corresponds to 20 log A/B decibels. One decibel represents a ratio of approximately 1.1 to1 between A and B

Degauss: to demagnetize; for example, demagnetizing video tape to completely erase the data. To return the magnetisation in a media coating or in a head to a zero state by applying a decaying and alternating magnetic field

Degaussing: degaussing or demagnetizing describe the use of an external degausser or bulk eraser erase data from magentic media.

DDS: Digital Data Storage tape

Disk/Diskette: Removable magnetic media storage, usually 3.5" square

Diskette: A flexible, circular substrate made of polyester, coated on one or both sides with magnetic oxide, ands designed to re4ceive and store electrically coaded information for later retrieval.

DLT: Digital Linear tape, magnetic tape technology originally developed by Digital for its VAX line.

DVC Pro: Digital Video tape

D-VHS: Digital Video Home System

EP: Extra Pulse Caused by minor media defects of contaminants on a disk when DC biased.

Exabyte: Tape cartridge manufacturer

FCI: Flux changes per inch

Flippy: A diskette which has been certified on both sides to be 100 percent error-free and thus able to be "flipped" over for use on either side.

Floppy: The term used to describe a diskette's characteristic flexibility when free of its protective jacket

Flux: Lines of magnetic force

Formatted capacity: The maximum amount of data bytes that can be stored on the media

Gauss: A unit of measurement of magnetic flux density produced by a magnetic force (coils).Gauss is the amount of energy that is produced by a magnetic force (coils). Gauss is a measurement of coil strength.

Hard error: An error that is repeatable in the same track and sector location

HDD: Hard disk drive sometimes referred to as HD

Hi-8: High-density camcorder tape

High energy tape: magnetic tape having coercivity higher than 600 Oersteds

kBPS: Kilobits per second

Magnetic flux: The magnetic lines of force produced by a magnet for electric current

Magnetic field strength: The magnitude of a magnetic field vector, usually expressed in oersteds or ampere-turns per meter.

MMF: magnetomotive force The magnetic analogue of electromotive force, which, when due to a current in a coil, is proportional to the product of current in amperes and the number of turns.

MP: Missing Pulse. Caused by minor media defects or contaminants on the surface of a disk.

Maxwell: A unit of magnetic flux

Oersted: A cgs unit of magnetic field strength, symbol: Oe. Oersted is a measurement applied to magnetic media. Most of "today's" tapes have an energy level rating of 1800 oersted or higher.

Overwrite: Overwrite of an FMM (digital) recording with the two frequencies 1f amnd 2f is defined as the ratio of the original 1f (of half band edge signal) to that remaininbg after being overwritten with 2f (or band edge signal). Overwrite of 30 dB is considered adequate for proper system performance.

Pancake: tape spooled on a hub in a pancake shape

QIC: Quarter-Inch Cartridge Drive standard

Retentivity: The maximum value of the residual flux density corresponding to saturation flux density.

S-VHS: Super Home Video System

TK50/TK75: tapes for TK50/TK75 tape cartridge system

TPI: Tracks per inch

Track: That protion of a recorded surface available to one read/write head at each access position. Also an area of tape surface that coincides with the location of the recordrd magnetisation produced by one record gap. 
Travan: Type of data cartridge

U-matic: 3/4" tape format

VHS: Video Home System. VHS tapes are often used in consumer Video Cassette Recorders (VCRs) and in CCTV systems.

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