|
| 1) Introduction
of Optical Discs. |
| : |
Along with the technological and social development has come
an explosive amount |
| |
of data to deal with. As a result, devices used to store the
data are continuously required to be equipped with the following
features: |
|
 | High Capacity |
| High Reliability |
| Random Access |
| Treatment Easiness (Broad Compatibility) |
|
Optical discs was the result of the comprehensive
efforts to meet these requirements.
Optical disc technology has been applied extensively, first
in compact disc formats in 1982. Optical discs are divided into
three kinds based on the kind of information stored: audio,
video and data discs. Recently, however, these are incorporated
into one under the name of Multi-Media. Another way to classify
optical discs is to divide them into read-only, write-once and
rewritable discs. |
|
| Classification |
AUDIO |
VIDEO |
DATA |
Combined |
Remarks |
|
|
|
|
|
|
| Read Only |
CD-DA
DVD-AUDIO |
VIDEO CD
DVD-VIDEO |
CD-ROM
DVD-ROM |
CD-I
PHOTO CD
game CD |
LD |
| Write
Once |
CD-R,
DVD-R |
CD-R,
DVD-R |
CD-R,
DVD-R |
CD-R,
DVD-R |
WORM-OD |
| Rewritable |
CD-RW
DVD-RW/+RW
DVD-RAM |
CD-RW
DVD-RW/+RW
DVD-RAM |
CD-RW
DVD-RW/+RW
DVD-RAM |
CD-RW
DVD-RW/+RW
DVD-RAM |
MOD
PC-OD |
|
Note |
Usages of recordable
discs depend on their application. |
|
| |
| 2) Introduction of DVD |
| : |
Video CD and Laserdisc, the two existing formats of optical
discs for video images had not |
| |
been able to satisfy the needs of the market; Video CD couldn't
provide quality picture due to its limited capacity, and Laserdisc
was just too huge (30cm in diameter). Markets wanted a better
alternative that would accomodate a complete movie on a single
disc with laserdisc-level video resolution and high-quality
stereo sound. Of course, the alternative were to be small enough
for easy treatment. These growing market needs came at the same
time with the development of related technologies, including
MPEG-2 video coding, variable bit rate, modulation and demodulation,
error correction and shortwave laser. These finally led to the
development of DVD. |
