G
LOSSARY
CD:
Short for compact disc, an optical disc storage format developed by Philips
and Sony.
CD Duplication:
The process of making one or more copies of a compact disc.
CD+G:
CD+Graphics. Audio, text and graphics used in the same application. This
type of disc is usually used for Karaoke machines.
CD-DA:
Compact Disc-Digital Audio. A CD-DA disc contains tracks with audio sec-
tors only. In 1982 Philips and Sony introduced the necessary technology
for storing digital audio signals on a compact disc, and introduced the CD-
Digital Audio.
CD-R [Disc]:
An acronym for compact disc-recordable which is a type of media
that allows you to record information using a CD Recorder.
CD-Recordable:
CD-Recordable technology allows production of CD-ROMs on
the desktop ('one-offs'). It requires a PC, a CD-R recorder or drive, appropri-
ate software, and 'recordable' media. The reduction of prices for this hard-
ware and software, and their ease of use, has helped the growth of CD-ROM
production in-house. The 'one-off' is very different from the mass- repro-
duced or 'hot-pressed' CDs. It is sold pre-grooved, in 63 or 74 minute capaci-
ties, and it involves a layered structure--with a sensitive chemical recording
layer, and almost always with a gold reflective layer. Once recorded, the CD-
R disc (one-off)performs in the same way as the mass-reproduced CDs.
CD-ROM:
Compact Disc-Read Only Memory. A standard for compact disc to be
used as a digital memory medium for personal computers. The specifica-
tions for CD-ROM were first defined in the Yellow Book.
CD-ROM Disc:
A CD-ROM disc contains only data sectors as defined in the
Yellow Book.
CD-ROM Drive:
A peripheral device attached to a computer which allows it to
read/play a CD-ROM disc. All CD-ROM players can also play back audio CDs,
but you need external headphones or speakers to hear them.
Compact Disc:
CD stands for compact disc which is a general term for all for-
mats of CD media. CD formats available on the market now include CD
Audio, CD-ROM, CD-ROMXA, Video CD, CD-I and others.
Compact Disc Formats:
During the last two decades several Compact
Disc formats were developed to serve different purposes and uses.
Starting with the CD-DA format in 1980, as a way to distribute high quality
music in a compact and convenient format, the first compact disc stan-
dard was formulated. Then, the idea of storing computer data on the same
media, more than 10 years ago, lead to a new format: the CD-ROM (along
with CD). In the last few years, the desire to store a whole new generation
of multimedia contents(audio, video, games, pictures etc.) demanded new
formats: CD-I,CD-XA, Photo-CD, Video-CD, CD+ etc. were invented.
Digital Audio:
Although digital audio can have a variety of sampling rates and
quantization, the Red Book specifies CD-Digital Audio as being sampled at
44.1KHz, and quantized at 16 bits/sample, for high quality stereo sound
(65,536 values).Therefore, sound of different quality, even if it is placed in
a CD, is not Red Book Digital Audio.
Digital Audio Extraction (DAE):
The process of copying CD-DA audio tracks digi-
tally from your CD-writer or another CD-ROM drive, to a hard disk or to a
recordable CD. Not all CD-ROM drives support this.
Disc Read Head-Disc Write Head:
Storage drives (magnetic and optical) have a
head or heads that float over the recorded area to read and write. Obviously,
CD-ROM drives have only a read head, which involves a low-intensity red
laser diode (a.k.a. infrared laser diode), lenses that focus the laser on the
track, and others that redirect the reflections to one of the photodiodes for
appropriate decoding. Some Write-Once and Rewritable optical drives
involve two heads (to write and read), while other drives, including CD-
Recordable, use only one head to do both--using a high-intensity blue argon
laser for the write function. For mass replication of CD-Audio, CD-ROM, and
DVDs, the glass master is produced by encoders that have special recording
heads.
Disc-At-Once (DAO):
A method of writing in which one or more tracks are writ-
ten in a single operation. The laser will not stop until the whole disc record-
ing is finished and the disc is closed - hence no no clicks between audio
tracks. Disc-at-Once has only been added/available with the recent genera-
tion of CD recorders and recent firmware upgrades.
1-800-237-6666
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