Editing Optical disc (section)

====CD-ROM====

The [[CD-ROM]] format was developed by Sony and [[Philips]], introduced in 1984, as an extension of [[Compact Disc Digital Audio]] and adapted to hold any form of digital data. The same year, Sony demonstrated a [[LaserDisc]] data storage format, with a larger data capacity of 3.28&nbsp;GB.<ref>[https://www.youtube.com/watch?v=rbh1XP4kCT4 Japanese PCs (1984)] {{Webarchive|url=https://web.archive.org/web/20170707091011/https://www.youtube.com/watch?v=rbh1XP4kCT4 |date=2017-07-07 }} (14:24), ''[[Computer Chronicles]]''</ref>

In the late 1980s and early 1990s, Optex, Inc. of Rockville, MD, built an erasable optical digital video disc system {{US Patent|5,113,387}} using Electron Trapping Optical Media (ETOM){{US Patent|5,128,849}}. Although this technology was written up in Video Pro Magazine's December 1994 issue promising "the death of the tape", it was never marketed.

Magnetic disks found limited applications in storing the data in large amount. So, there was the need of finding some more data storing techniques. As a result, it was found that by using optical means large data storing devices can be made that in turn gave rise to the optical discs. The very first application of this kind was the compact disc (CD), which was used in audio systems.

Sony and Philips developed the first generation of the CDs in the mid-1980s with the complete specifications for these devices. With the help of this kind of technology the possibility of representing the analog signal into digital signal was exploited to a great level. For this purpose, the 16-bit samples of the analog signal were taken at the rate of [[44,100 Hz|44,100 samples per second]]. This sample rate was based on the [[Nyquist rate]] of 40,000 samples per second required to capture the audible frequency range to 20&nbsp;kHz without aliasing, with an additional tolerance to allow the use of less-than-perfect analog audio pre-filters to remove any higher frequencies.<ref>Hass, J. ''Introduction to Computer Music'', Indiana University CECM (retrieved 8 October 2014), Volume One, Chapter Five: Digital Audio.{{cite web|title=Chapter Five: Principles of Digital Audio|url=http://www.indiana.edu/~emusic/etext/digital_audio/chapter5_rate.shtml|url-status=dead|archive-url=https://web.archive.org/web/20140608134439/http://www.indiana.edu/%7Eemusic/etext/digital_audio/chapter5_rate.shtml|archive-date=2014-06-08|access-date=2014-10-08}}</ref> The first version of the standard allowed up to 74 minutes of music or 650&nbsp;MB of data storage.