Comparison of popular optical data-storage systems

Comparison of popular optical data-storage systems

This article provides a Comparison of popular optical data-storage systems.

As of 2007 these are:

and their successors (formerly engaged in a format war):




In optical storage, three types of storage are usually recognized, and given customary abbreviations: read-only ("ROM"), Write once ("R") and read/writable ("RW", or for Blu-ray, "E" for "erasable"). Examples:

  • CD-ROM represents the CD format, in its pre-recorded "read only" use
  • DVD+R represents a DVD "+" disc which can be written once only
  • DVD-RW represents a DVD "-" disc which can be read or written many times
  • BR-E represents a Blu-ray disc which can be read or written many times.

In addition some of these media support MultiLevel Recording formats, for example dual layer (written as "DL"), and DVD also supports a "RAM" version (similar to RW), although this is not widely used in the popular consumer market.


DVD has three variants, known as "+", "-" and "RAM". For the purposes of this article, DVD+ and DVD- are considered together as "DVD"; they share many of the same characteristics. Differences are noted below.

DVD-RAM, which did not gain wide penetration of the consumer market, is discussed briefly in the same section but otherwise excluded from the article.

ROM formats are excluded; they perform rather like write-once "R" formats, without the capacity to write to the disc. Likewise other niche formats are excluded, such as GD-ROM (used by some Sega game consoles) and Ultra Density Optical and the like (commercial archiving storage rather than mass market).

Thus the article covers the following popular recordable formats: CD (CD-R, CD-RW); DVD (DVD±R, DVD±RW); HD DVD (); Blu-ray (BD-R, BD-E), and for all except CD, their respective dual- or multi-layer formats.


Although research into optical data storage has been ongoing for many decades, the first popular system was CD-ROM, introduced in 1982, adapted to data storage (the CD-ROM format) with the 1985 Yellow Book, and re-adapted as the first mass market optical storage medium with CD-R and CD-RW in 1988. Compact Disc is still the de facto standard for audio recordings, although its place for other multimedia recordings and optical data storage has largely been superseded by DVD.

DVD (initially an acronym of "Digital Video Disc", then backronymed as "Digital Versatile Disc" and officially just "DVD") was the mass market successor to CD. DVD was rolled out in 1996, again initially for video and audio. DVD recordable formats developed some time later: DRD- in late 1997 and DVD+ in 2002. Although DVD was initially intended to prevent a format war in fact one did arise between these two formats. It was resolved with both surviving however: DVD-R predominating for stand-alone DVD recorders and players, and (for computers) most DVD devices being engineered as dual format, to be compatible with both. As of 2007 DVD is the de facto standard for pre-recorded movies, and popular storage of data beyond the capacity of CD.

With the development of high definition television, and the popularization of broadband and digital storage of movies, a further format development took place, again giving rise to two camps: HD DVD and Blu-ray, based upon a switch from red to blue-violet laser and tighter engineering tolerances. As of 2007 both have significant releases in the pre-recorded movie sector, but they are still only commencing their roll-out for data storage and more general use, and have as yet made little impact on the global market for data storage. The result of this format war is not yet determined.

Technology comparisons


Optical device speeds are often quoted as a multiple of a "basic speed" for that type of device. Thus for CD, the basic speed is 150 kB/s, so a CD-recordable device may be quoted as "4x" or "6x" to indicate a speed of 600 kB/s and 900 kB/s respectively.

Typical values are:


Speed MB/s
1x 0.15
4x 0.6
24x 3.6
48x 7.2
52x 7.8


Speed MB/s CD equivalent
1x 1.32 9x
4x 5.28 36x
6x 7.93 54x
12x 15.85 --
16x 21.13 --


Speed MB/s DVD equivalent
1x 4.5 3x
2x 9.0 7x
4x 18.0 14x

sources: [3]

Also, these speeds are not constant, and are usually a measure of the maximum possible speed a drive can achieve.

Data Capacity

Filing systems

Copy protection systems

Optical technology used

Other information


Optical storage devices excluded from article

The following are examples of optical storage media excluded from this article:

  • Holographic data storage - either still in development, or available but generally only encountered in niche usage as of 2007.
  • Laserdisc - not used for recordable data storage in the computing world.
  • Optical jukebox - hold massive amounts of data on multiple discs allowing scalability into the petabyte range.

See also

External links

Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Comparison of analog and digital recording — This article compares the two ways in which sound is recorded and stored. Actual sound waves consist of continuous variations in air pressure. Representations of these signals can be recorded using either digital or analog techniques. An analog… …   Wikipedia

  • Data compression — Source coding redirects here. For the term in computer programming, see Source code. In computer science and information theory, data compression, source coding or bit rate reduction is the process of encoding information using fewer bits than… …   Wikipedia

  • Computers and Information Systems — ▪ 2009 Introduction Smartphone: The New Computer.       The market for the smartphone in reality a handheld computer for Web browsing, e mail, music, and video that was integrated with a cellular telephone continued to grow in 2008. According to… …   Universalium

  • Control Data Corporation — (CDC) was a supercomputer firm. For most of the 1960s, it built the fastest computers in the world by far, only losing that crown in the 1970s after Seymour Cray left the company to found Cray Research, Inc. (CRI). CDC was one of the nine major… …   Wikipedia

  • Early IBM disk storage — The invention of magnetic disk storage, pioneered by IBM in the 1950s, was a critical component of the computer revolution. This article surveys the major IBM computer disk drives introduced in the 1950s, 1960s and early 1970s. The basic… …   Wikipedia

  • HD DVD — Media type High density optical disc Encoding …   Wikipedia

  • Maglev — JR Maglev at Yamanashi, Japan test track in November 2005 …   Wikipedia

  • Carbon nanotube — Not to be confused with Carbon fiber. Part of a series of articles on Nanomaterials Fullerenes …   Wikipedia

  • Nanotechnology — Part of a series of articles on …   Wikipedia

  • Hydrogen economy — The hydrogen economy is a proposed system of delivering energy using hydrogen. The term hydrogen economy was coined by John Bockris during a talk he gave in 1970 at General Motors (GM) Technical Center.[1] Hydrogen advocates promote hydrogen as… …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”

We are using cookies for the best presentation of our site. Continuing to use this site, you agree with this.