# compact disc

> digital optical disc data storage format

**Wikidata**: [Q34467](https://www.wikidata.org/wiki/Q34467)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Compact_disc)  
**Source**: https://4ort.xyz/entity/compact-disc

## Summary
The compact disc (CD) is a digital optical disc data storage format developed in 1979 by Philips and Sony. It stores up to 700 megabytes of data and was designed to replace vinyl records and cassette tapes for audio distribution.

## Key Facts
- Inception: 1979, developed by Philips Natuurkundig Laboratorium and Sony Group
- Storage capacity: 700 megabytes (MB)
- Physical format: 120mm diameter optical disc with digital data encoded in binary
- First audio CD released: 1982, using the Compact Disc Digital Audio format
- Creator: Philips Natuurkundig Laboratorium (Philips Research Lab)
- Replaces: vinyl records and phonograph records
- Followed by: DVD (Digital Versatile Disc)
- Instance of: physical media format, audio release format, product category
- Storage type: optical disc, machine-readable medium, computer storage media
- Museum of Modern Art work ID: 90095

## FAQs
### Q: What is a compact disc used for?
A: A compact disc is used to store and distribute digital data, primarily audio music, computer software, and video content. It replaced analog formats like vinyl records and cassette tapes.

### Q: How much data can a CD hold?
A: A standard compact disc can hold up to 700 megabytes of data, which translates to approximately 80 minutes of audio or thousands of digital files.

### Q: Who invented the compact disc?
A: The compact disc was co-developed by Philips (Netherlands) and Sony (Japan) in 1979, with significant contributions from engineer Kees Schouhamer Immink.

## Why It Matters
The compact disc revolutionized digital data storage and distribution when it was introduced in the early 1980s. It provided a durable, high-quality alternative to analog audio formats like vinyl records and cassette tapes, offering superior sound quality with no degradation from repeated playback. The CD's digital format enabled perfect copies and random access to tracks, transforming how people listened to music and stored data. Its success established optical disc technology as a dominant medium for physical media distribution throughout the 1990s and early 2000s, influencing the development of subsequent formats like DVD and Blu-ray. The CD also played a crucial role in the transition from analog to digital media, helping to standardize digital audio encoding and paving the way for modern digital music distribution.

## Notable For
- First widely successful digital optical storage format for consumer use
- Established the 120mm diameter standard that influenced all subsequent optical disc formats
- Enabled perfect digital copies without quality degradation
- Replaced vinyl records as the dominant music distribution format in the 1990s
- Pioneered the use of error correction technology in consumer optical media

## Body
### Development and Technology
The compact disc was developed through a collaboration between Philips and Sony in the late 1970s. The format uses a 1.2mm thick polycarbonate plastic substrate with a spiral track containing microscopic pits that represent binary data. A thin aluminum reflective layer and protective lacquer coating complete the disc structure. The CD operates using a 780nm wavelength laser to read the data encoded in the spiral track.

### Audio Format Specifications
The original Compact Disc Digital Audio format, introduced in 1982, uses Pulse Code Modulation (PCM) encoding at 16-bit resolution with a 44.1 kHz sampling rate. This provides a frequency response of 20 Hz to 20 kHz, covering the full range of human hearing. The Red Book standard defines the technical specifications for audio CDs, including track structure, error correction, and subcode information.

### Variations and Applications
Beyond audio, the CD format expanded to include CD-ROM for computer data storage, CD-R for recordable discs, and CD-RW for rewritable media. The Video CD (VCD) format enabled video playback, while CD+G added graphics capabilities. Specialized formats like Mini CD (80mm diameter) and business card CD offered alternative form factors for specific applications.

### Cultural Impact
The CD became the dominant music format throughout the 1990s, fundamentally changing music consumption patterns. Record stores transitioned from vinyl to CD displays, and consumers built digital music libraries. The format's durability and sound quality made it preferable to cassettes and vinyl for many users. CD sales peaked in the early 2000s before declining with the rise of digital downloads and streaming services.

### Technical Legacy
The CD's success established optical disc technology as a reliable storage medium, influencing the development of DVD, Blu-ray, and other optical formats. The 120mm diameter standard became the reference size for optical discs, and the error correction techniques developed for CD were adapted for subsequent formats. The CD also helped standardize digital audio encoding, contributing to the development of MP3 and other digital audio formats.

## Schema Markup
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  "@type": "Thing",
  "name": "compact disc",
  "description": "digital optical disc data storage format",
  "url": "https://en.wikipedia.org/wiki/Compact_disc",
  "sameAs": [
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## References

1. Google Product Taxonomy
2. Museum of Modern Art online collection
3. [Source](https://www.moma.org/collection/works/90095)
4. Freebase Data Dumps. 2013
5. BBC Things
6. YSO-Wikidata mapping project
7. Controlled Vocabulary for Dublin Core format
8. UMLS 2023
9. [Source](https://www.philips.com/a-w/research/technologies/cd/cd-family.html)
10. Quora
11. [Compact Disk | Home Wiki | Fandom](https://home.fandom.com/wiki/Compact_Disk)
12. National Library of Israel
13. KBpedia
14. [OpenAlex](https://docs.openalex.org/download-snapshot/snapshot-data-format)
15. Wikibase TDKIV