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Carrier-To-Noise
Ratio (CNR)
The ratio of the root-mean-square (RMS)
power of a signal at a specified frequency to the RMS
power of the noise in a specified bandwidth, expressed in
decibels (dB).
CD-R
Compact Disc-Recordable.
C List
SCSI Term. This list shows the positions of
defects detected during the initialised data block
verification of the FORMAT UNIT command. This list is
generated internally by the IDD during execution of the
FORMAT UNIT command
Composite Head
The composite head is composed primarily of
a ferrite core with a wire coil and a glass-filled gap,
and the material used to bond the core to the slider.
Ferrite is a hard material which makes it difficult to
meet today's physical and electrical characteristics
required for higher areal densities. Conventional ferrite
heads, such as this, have reached the limits of their
performance with regard to the machining processes and
magnetic characteristics in the high-frequency domain.
Cross Talk Level
The ratio of the level of a spurious signal
generated by an adjacent track to the level of the signal
of that adjacent track.
Curie Point
The temperature at which the polarity of a
magnetic material is easily changed. Normally associated
with optical disk technology.
Curie Temperature
The temperature above which a magnetic
material loses its magnetic properties and can be easily
magnetised by an applied magnetic field.
Closed Loop
Servo System
A correction system in the form of a loop
that has no exit, exchanging information about changes in
the constitution of the storage medium (e.g.
temperature-related expansion) and of the drive mechanics
in a feedback method between a reference track on the
medium and the head positioning. In this way,
irregularities may be corrected more easily, which is of
advantage for data integrity and which, particularly with
smaller drives, renders higher data densities secure.
This feedback technology is frequently accompanied by the
use of linear or rotary voice coil actuator technology.
Constant
Density Recording
In this technique, data is recorded at a
density approximately constant on all tracks therefore,
outer tracks have a larger capacity and higher data
transfer rate. In conventional recording, the track
capacity is based on the innermost track.
CRC
Cyclic Redundancy Check : frequently used
error-checking (correctness of memory contents) in the
read/write head zone.
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