Optical storage

Last updated

Writable optical data carriers Blank Recordable DVD-R Discs underside shallow focus.JPG
Writable optical data carriers

Optical storage refers to a class of data storage systems that use light to read or write data to an underlying optical media. Although a number of optical formats have been used over time, the most common examples are optical disks like the compact disc (CD) and DVD. Reading and writing methods have also varied over time, but most modern systems as of 2023 use lasers as the light source and use it both for reading and writing to the discs. [1] Britannica notes that it "uses low-power laser beams to record and retrieve digital (binary) data." [2] [3]

Contents

Overview

Optical storage is the storage of data on an optically readable medium. Data is recorded by making marks in a pattern that can be read back with the aid of light, usually a beam of laser light precisely focused on a spinning optical disc. An older example of optical storage that does not require the use of computers, is microform. There are other means of optically storing data and new methods are in development. An optical disc drive is a device in a computer that can read CD-ROMs or other optical discs, such as DVDs and Blu-ray discs. Optical storage differs from other data storage techniques that make use of other technologies such as magnetism, such as floppy disks and hard disks, or semiconductors, such as flash memory.

Optical storage in the form of discs grants the ability to record onto a compact disc in real time. Compact discs held many advantages over audio tape players, such as higher sound quality and the ability to play back digital sound. [4] Optical storage also gained importance for its green qualities and its efficiency with high energies. [5]

Optical storage can range from a single drive reading a single CD-ROM to multiple drives reading multiple discs such as an optical jukebox. Single CDs (compact discs) can hold around 700 MB (megabytes) and optical jukeboxes can hold much more. Single-layer DVDs can hold 4.7 GB, while dual-layered can hold 8.5 GB. This can be doubled to 9.4 GB and 17 GB by making the DVDs double-sided, with readable surfaces on both sides of the disc. HD DVDs were able to store 15 GB with a single-layer and 30 GB with a dual-layer. Blu-ray discs, which won the HDTV optical format war by defeating HD DVDs, can hold 25 GB for single-layer, 50 GB for dual-layer and up to 128 GB for quad-layer discs. Optical storage includes CDs and DVDs.

History

IBM was a leader in the development of optical storage systems for much of the early history of computing. In 1959, they installed the Automatic Language Translator, which used an optical disk holding 170,000 words and phrases in Russian and their translations in English. [6] In 1961/2, they introduced the IBM 1360, which used small photographic slides that were read using a conventional incandescent lamp as a light source and a photocell as a detector. A separate system wrote data to the slides using an electron gun, making it a read/write system. Fully expanded, the 1360 could hold about a half a terabit of data and allowed for semi-random access. [7] A similar 3rd party system was the Foto-Mem FM 390.

Various forms of optical media, mostly disk form, competed with magnetic recording through most of the 1960s and 70s, but never became widely used. It was the introduction of semiconductor lasers that provided the technology needed to make optical storage more practical in both storage density and cost terms. Prices fell to the point that they could be used in consumer products, leading to the 1978 introduction of the analog LaserDisc format. This was followed in August 1982 by the introduction of the digital audio audio/music CD, [8] which soon led to an effort to standardize data recording on this media. This was introduced in 1985 as the "Yellow Book", which became known as CD-ROM. [9]

In 1983, Philips introduced their early work on magneto-optical drive technology at an industry conference. This used a laser to warm the storage media so that it became susceptible to magnetic fields and an electromagnet, similar to the one in a hard drive, to write data by realigning the material within. It worked like a conventional optical drive during reads, with the laser operating at lower energy levels, too low to heat the disk. Rumors that IBM would use this in future versions of the IBM PC were common for a time, [10] but nothing ever came of this. Canon introduced a version packaged in a jacket similar to those used for the 3.5-inch floppy disk. Introduced in 1985, it found no major uses until 1988 when it was the centrepiece of the NeXT Computer. [11] Variations on this design were introduced through the 1990s but it never became very popular outside of Japan, although Sony's MiniDisc format saw some success. [12]

In 1988, the "Orange Book" added a write-once format, CD-WO, to the existing CD format. The media was compatible with existing CD drives, allowing music and data to be recorded and then read in any existing drive. Over time, this became known as CD-R. [9] In 1990, the Orange Book added magnetic-optical re-writable versions of the CD physical format, CD-MO, which differed from earlier MO systems primarily in that the disk was not enclosed in a jacket. This format saw little use. Continual improvements in drive and media led to the 1997 addition of the CD-RW format, which allowed disks to be written, erased and re-written. This format is incompatible with older CD drives, like CD-R, but read-only drives capable of reading CD-RW became common in the 2000s as CD-RW use proliferated.

Optical media took another large step with the 1996 introduction of DVD, which was to video what the CD was to music. Originally to be known as "digital video disc", the name changed before release to be "digital versatile disc" to indicate that it was also useful for computer storage. [13] Over time, DVDs followed a similar pattern as CDs; Pioneer introduced a write-once format in 1997 that could be read in existing DVD drives, DVD-R. [14] But a second write-once format DVD+R emerged in 2002, leading to a brief format war before dual format drives became common. A read-write format, DVD-RW, was introduced in 1999, but like earlier CDs it could not be read by "normal" DVD drives. Over time, improvements led to most newer DVD drives being able to read any of these media. [15]

Another technical improvement during this era was the introduction of higher-frequency semiconductor lasers operating in the blue and near ultraviolet spectrum. These shorter wavelengths, combined with improvements in the underlying media, allowed much more data to be stored on a disk. With the widespread introduction of high-definition television in the early 2000s, the need for a medium able to store the much larger higher-resolution video files became an issue, [16] leading to two competing standards, HD DVD and Blu-ray. The former could be produced on existing DVD production equipment but (initially) offered lower resolution video formats (and less data storage) while the later required new production equipment but offered 1080p support. Over time, Blu-ray won the resulting high-definition optical disc format war, with Toshiba announcing their withdrawal of HD DVD on February 19, 2008. This proved to be a Pyrrhic victory as the market quickly moved to streaming services. Blu-ray remains preferred to streaming services for its technical qualities, but has a tiny market share as of 2023. [17]

As of 2023, Blu-ray is the last major optical format to reach widespread use. The ever-increasing speed of broadband internet has replaced many of its roles as a distribution medium for media and video games, and the rapidly falling prices of Flash memory through the 2010s did the same in its archival role with read-write formats. A number of new technologies have been proposed as the basis for a new optical standard, but have not seen widespread use. These include:

The Optical Storage Technology Association (OSTA) was an international trade association formed to promote the use of recordable optical data storage technologies and products.

See also

Related Research Articles

<span class="mw-page-title-main">Compact disc</span> Digital optical disc data storage format

The compact disc (CD) is a digital optical disc data storage format that was co-developed by Philips and Sony to store and play digital audio recordings. The first compact disc was manufactured in August 1982, and was first released in Japan in October 1982 as Compact Disc Digital Audio. The CD was more compact than the LaserDisc (LD) developed in the 1970s. The CD gained rapid popularity in the 1990s. It quickly outsold all other audio formats in the United States by 1991, ending the market dominance of the cassette tape. By 2000, the CD accounted for 92.3% of the entire market share in regard to music sales. The CD is considered the last dominant audio format of the album era, as the rise of MP3, iTunes, cellular ringtones, and other downloadable music formats in the mid-2000s ended the decade-long dominance of the CD.

<span class="mw-page-title-main">CD-R</span> Recordable optical disc specification

CD-R is a digital optical disc storage format. A CD-R disc is a compact disc that can be only written once and can only be read designated/limited times.

<span class="mw-page-title-main">Disk storage</span> General category of storage mechanisms

Disk storage is a general category of storage mechanisms where data is recorded by various electronic, magnetic, optical, or mechanical changes to a surface layer of one or more rotating disks. A disk drive is a device implementing such a storage mechanism. Notable types are hard disk drives (HDD) containing one or more non-removable rigid platters, the floppy disk drive (FDD) and its removable floppy disk, and various optical disc drives (ODD) and associated optical disc media.

<span class="mw-page-title-main">Optical disc</span> Flat, usually circular disc that encodes binary data

An optical disc is a flat, usually disc-shaped object that stores information in the form of physical variations on its surface that can be read with the aid of a beam of light. Optical discs can be reflective, where the light source and detector are on the same side of the disc, or transmissive, where light shines through the disc to be detected on the other side.

<span class="mw-page-title-main">Optical disc drive</span> Type of computer disk storage drive

In computing, an optical disc drive is a disc drive that uses laser light or electromagnetic waves within or near the visible light spectrum as part of the process of reading or writing data to or from optical discs. Some drives can only read from certain discs, but recent drives can both read and record, also called burners or writers. Compact discs, DVDs, and Blu-ray discs are common types of optical media which can be read and recorded by such drives.

<span class="mw-page-title-main">Magneto-optical drive</span>

A magneto-optical drive is a kind of optical disc drive capable of writing and rewriting data upon a magneto-optical disc. 130 mm (5.25 in) and 90 mm (3.5 in) discs were the most common sizes. In 1983, just a year after the introduction of the compact disc, Kees Schouhamer Immink and Joseph Braat presented the first experiments with erasable magneto-optical compact discs during the 73rd AES Convention in Eindhoven. The technology was introduced commercially in 1985. Although optical, they normally appear as hard disk drives to an operating system and can be formatted with any file system. Magneto-optical drives were common in some countries, such as Japan, but have fallen into disuse.

<span class="mw-page-title-main">DVD-RAM</span> Variant of DVD designed with random access in mind

DVD-RAM is a DVD-based disc specification presented in 1996 by the DVD Forum, which specifies rewritable DVD-RAM media and the appropriate DVD writers. DVD-RAM media have been used in computers as well as camcorders and personal video recorders since 1998.

<span class="mw-page-title-main">Holographic Versatile Disc</span> Novel optical disc based on holography

The Holographic Versatile Disc (HVD) is an optical disc technology that was expected to store up to several terabytes of data on an optical disc 10 cm or 12 cm in diameter. Its development commenced in April 2004, but it never arrived due to lack of funding. The company responsible for HVD went bankrupt in 2010.

MultiLevel Recording was a technology originally developed by Optex Corporation and promoted by Calimetrics to increase the storage capacity of optical discs. It failed to establish itself on the market. Through a combination of proprietary media, recorder, reader and player modifications, Calimetrics proposed that ML could increase the capacity of a CD-ROM, CD-R or CD-RW to 2 GB, a single-layer DVD, DVD-R, DVD+R, DVD-RW, DVD+RW or DVD-RAM to 7.1 to 10 GB and a single-layer Blu-ray Disc (BD) to as much as 60 GB. An optionally integrated Digital Rights Management (DRM) system entitled MovieGuard was also suggested. An industry group called the ML Alliance was formed in 2000 to help commercialize ML technology. Members eventually included Calimetrics, TDK, Sanyo Semiconductor, Plextor, Matsushita Kotobuki Electronics, Mitsubishi Chemical Corporation, Verbatim, Teac and Yamaha.

The double-density compact disc (DDCD) is an optical disc technology developed by Sony and Philips using the same 780 nm laser wavelength as a compact disc. The format was announced in July 2000 and is defined by the Purple Book standard document. Unlike the compact-disc technology it is based on, DDCD was designed exclusively for data, with no audio capabilities.

<span class="mw-page-title-main">Professional Disc</span> Proprietary optical disc format developed by Sony for storing digital video

Professional Disc (PFD) is a digital recording optical disc format introduced by Sony in 2003 primarily for XDCAM, its tapeless camcorder system. It was one of the first optical formats to utilize a blue laser, which allowed for a higher density of data to be stored on optical media compared to infrared laser technology used in the CD and red laser technology used in the DVD format.

In computing, external storage refers to non-volatile (secondary) data storage outside a computer's own internal hardware, and thus can be readily disconnected and accessed elsewhere. Such storage devices may refer to removable media, compact flash drives, portable storage devices, or network-attached storage. Web-based cloud storage is the latest technology for external storage.

<span class="mw-page-title-main">DVD recordable</span> Recordable optical disk technology

DVD recordable and DVD rewritable are optical disc recording technologies. Both terms describe DVD optical discs that can be written to by a DVD recorder, whereas only 'rewritable' discs are able to erase and rewrite data. Data is written ('burned') to the disc by a laser, rather than the data being 'pressed' onto the disc during manufacture, like a DVD-ROM. Pressing is used in mass production, primarily for the distribution of home video.

<span class="mw-page-title-main">Optical disc recording technologies</span> List of technologies used to write to optical discs

Optical disc authoring requires a number of different optical disc recorder technologies working in tandem, from the optical disc media to the firmware to the control electronics of the optical disc drive.

<span class="mw-page-title-main">CD-RW</span> Optical disk technology

CD-RW is a digital optical disc storage format introduced in 1997. A CD-RW compact disc (CD-RWs) can be written, read, erased, and re-written.

<span class="mw-page-title-main">DVD</span> Optical disc format

The DVD is a digital optical disc data storage format. It was invented and developed in 1995 and first released on November 1, 1996, in Japan. The medium can store any kind of digital data and has been widely used to store video programs, software and other computer files. DVDs offer significantly higher storage capacity than compact discs (CD) while having the same dimensions. A standard single-layer DVD can store up to 4.7 GB of data, a dual-layer DVD up to 8.5 GB. Variants can store up to a maximum of 17.08 GB.

<span class="mw-page-title-main">HD DVD</span> Obsolete optical disc format

HD DVD is an obsolete high-density optical disc format for storing data and playback of high-definition video. Supported principally by Toshiba, HD DVD was envisioned to be the successor to the standard DVD format, but lost to Blu-ray, supported by Sony and others.

As of 2021, multiple consumer-oriented, optical-disk media formats are or were available:

The preservation of optical media is essential because it is a resource in libraries, and stores audio, video, and computer data to be accessed by patrons. While optical discs are generally more reliable and durable than older media types, environmental conditions and/or poor handling can result in lost information.

<span class="mw-page-title-main">CD-ROM</span> Pre-pressed compact disc containing computer data

A CD-ROM is a type of read-only memory consisting of a pre-pressed optical compact disc that contains data. Computers can read—but not write or erase—CD-ROMs. Some CDs, called enhanced CDs, hold both computer data and audio with the latter capable of being played on a CD player, while data is only usable on a computer.

References

  1. ↑ "Optical storage". IBM .
  2. ↑ "Optical storage". britannica.com.
  3. ↑ "What is optical storage?". optical media, such as compact discs (CDs) and DVDs.
  4. ↑ ,"Optical storage device",issued 1998-07-08
  5. ↑ Gu, Min; Li, Xiangping; Cao, Yaoyu (May 2014). "Optical storage arrays: a perspective for future big data storage". Light: Science & Applications. 3 (5): e177. doi: 10.1038/lsa.2014.58 . ISSN   2047-7538.
  6. ↑ Benjamins, Joh (2000). Hutchins, John (ed.). Gilbert W. King and the IBM-USAF Translator (PDF). Collection: Early Years in Machine Translation. ISBN   90-272-4586-X.
  7. ↑ Kuehler, J. D.; Kerby, H. Ray (1966). A photo-digital mass storage system. Proceedings of the November 7–10, 1966, fall joint computer conference. American Federation of Information Processing Societies. pp. 735–742.
  8. ↑ Benj Edwards (October 1, 2012). "The CD player turns 30". PCWorld. Retrieved November 9, 2016. On October 1, 1982, Sony ignited a digital audio revolution with the release of the world's first commercial compact disc player, the CDP-101 (above), in Japan.
  9. 1 2 "From disk to data: how CD-R immortalizes your data in plastic". InfoWorld . Vol. 16, no. 23. June 6, 1994. p. 88. Retrieved March 25, 2020.
  10. ↑ Erik Sandberg-Diment (March 31, 1985). "Is optical memory next from I. B. M.?". The New York Times .
  11. ↑ Thompson, Tom; Baran, Nick (November 1988). "The NeXT Computer". Byte. p. 158.
  12. ↑ "The story of the MiniDisc". Open Culture. June 23, 2021.
  13. ↑ "Backronym definition". Pcmag . Archived from the original on March 15, 2012.
  14. ↑ "History of Pioneer Corporation". Pioneer Corporation. Archived from the original on July 15, 2017. Retrieved December 6, 2019.
  15. ↑ "Notice to the DVD-RW Book Subscribers" (2004-02-25). www.dvdforum.org. Retrieved July 27, 2020. Important Notice to the subscribers of the DVD-RW Format Specifications Book Ver.1.2
  16. ↑ Evan Ramstad (April 8, 1998). "In HDTV Age, Successor to VCR Still Seems to Be a Long Way Off". online.wsj.com. Retrieved October 18, 2007.
  17. ↑ Williams, Mike (February 9, 2022). "6 Reasons Physical Media Beats Streaming". PC Magazine. Retrieved June 30, 2023.
  18. ↑ Kleiner, Kurt (May 17, 2006). "Ultraviolet LED may boost disc capacity". New Scientist. Retrieved April 18, 2022.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.