27-07-2012, 11:59 AM
GENERATION OF OPTICAL DISCS
GENERATION OF OPTICAL DISCS.ppt (Size: 2.15 MB / Downloads: 33)
INTRODUCTION
Invented by Philips in 1977, the Compact Disc (CD) was first commercially manufactured in 1982. The production process was further refined and by 1987, the introduction of the first inline machine heralded a new era of CD production.
Towards increasing the storage capacity of Optical Disks, Philips, Sony and SD alliance announced their intention of creating the Digital Video Disc in 1995. Today, both CDs and DVDs have become industry standards in storage, archival, transmission and distribution of data, software and entertainment.
Type of optical discs
Pre-recorded:-
These are discs which are manufactured with the data they are to contain. They can be read-from but no additional data can be added to them. Examples: CD, DVD.
Recordable:-
These discs, when manufactured, are blank and contain no data. Data can be written on to these discs only once. In other words, data once recorded can neither be erased nor over-written. Examples: CD-R, DVD-R, +R.
Re-writable:-Manufactured as blanks, these discs allow data to be written, erased and overwritten many times. Examples: CD-R, DVD-R, +RW.
First generation
first-generation disc formats were designed only to store digital data and were not initially capable of use as a digital video medium.
In First generation One example of high-density data storage capacity, achieved with an infrared laser, is 700 MB of net user data for a 12 cm compact disc.