Reference
CD-ROM
Abbreviation for “Compact Disc Read
Only Memory.”
Reference
CD-R
Abbreviation for “Compact Disc Recordable.”
(2)Optical disks
An “optical disk” is a type of storage device that uses laser optics to read
and write data.
The characteristics and storage capacities of typical optical disks are summarized below.
Storage
device
Storage
media
CD-ROM
drive
CD-ROM
A read-only media. Due to its low
cost, CD-ROMs are widely used to
distribute software packages.
CD-R
drive
CD-R
A media that reads and writes data.
Data can only be written once, after
which the data becomes read-only.
Also referred to as a “write once, read
many disc.” Data that is recorded to a
CD-R can be read by CD-ROM devices.
CD-RW
drive
CD-RW
A media that reads and writes data.
Can be rewritten about 1,000 times.
DVDROM
drive
DVDROM
A read-only media that is widely used
to distribute movies and other largevolume video software.
DVDRAM
drive
DVDRAM
A media that reads and writes data.
Used to record large-volume video
from devices such as digital video
cameras.
DVD-R
drive
DVD-R
A media that reads and writes data.
Data can only be written once, after
which the data becomes read-only.
Data that is recorded to a DVD-R can
be read by DVD-ROM devices or
DVD players.
DVD-RW
drive
DVD-RW
A media that reads and writes data.
Can be rewritten about 1,000 times,
similar to a CD-RW.
Blu-ray
drive
Blu-ray
A media that reads and writes data.
The Blu-ray format was jointly developed by a consortium of nine companies including Sony and Panasonic.
Uses the same 12-cm diameter optical disc cartridges as CDs and DVDs.
Used as a large-capacity storage media for data such as video.
Reference
CD-RW
Abbreviation for “Compact Disc Rewritable.”
Reference
DVD-ROM
Abbreviation for “Digital Versatile Disc
Read-Only Memory.”
Reference
DVD-RAM
Abbreviation for “Digital Versatile Disc
Random Access Memory.”
Reference
DVD-R
Abbreviation for “Digital Versatile Disc
Recordable.”
Reference
DVD-RW
Abbreviation for “Digital Versatile Disc
Rewritable.”
Reference
Shelf life of optical discs
Data on optical discs is protected by a
thin resin protection layer on top of the
recording layer where data is stored.
Using an optical disc for many years
can result in deterioration of the protection layer and loss of the stored content.
197
Characteristics
* Approximate capacities as of May 2009.
Storage capacity
650MB
700MB
Single-sided,
single-layer:
4.7GB
Single-sided,
dual-layer: 8.5GB
* Capacities are
doubled for
double-sided
media
Single-sided,
single-layer:
25GB
Single-sided,
dual-layer: 50GB