# CD-R

> compact disc format that can be written once and read arbitrarily many times

**Wikidata**: [Q420778](https://www.wikidata.org/wiki/Q420778)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/CD-R)  
**Source**: https://4ort.xyz/entity/cd-r

## Summary
CD-R (Compact Disc Recordable) is a digital optical disc format that can be written once and read arbitrarily many times. Introduced in 1988, it is a variation of the standard Compact Disc co-developed by Philips and Sony, allowing users to record data onto a disc rather than just reading pre-manufactured content.

## Key Facts
- **Entity Type:** Compact disc format; Subclass of compact disc and machine-readable medium.
- **Core Function:** Write Once, Read Many (WORM) capability; data can be written a single time but read arbitrarily many times.
- **Publication Date:** June 13, 1988.
- **Inventors:** Taiyo Yuden, Koninklijke Philips NV, and Sony Group.
- **Parent Format:** Compact Disc (incepted 1979).
- **Storage Capacity:** Up to 700 megabytes (MB) / approximately 80 minutes of audio (derived from parent format).
- **Physical Dimensions:** 120mm diameter (standard), 1.2mm thick polycarbonate plastic.
- **Technical Standard:** Part of the "Rainbow Books" standards; associated with the "Orange Book" and ECMA-394.
- **Aliases:** CD-Recordable, CD Write-Once, CD-WO, CD-WORM, CD+R, CDr, CD R, CD vierage, CD-Rohling.

## FAQs

### Q: What is the difference between a CD-R and a standard CD?
A: While a standard Compact Disc is pressed with pre-recorded data during manufacturing, a CD-R is a blank medium that allows data to be recorded onto it once by a user using a laser recorder.

### Q: Who developed the CD-R technology?
A: The format was developed by Taiyo Yuden, Koninklijke Philips NV, and Sony Group, following the establishment of the original Compact Disc standard.

### Q: Can a CD-R be erased and reused?
A: No, the format is defined by its ability to be written only once. Once data is recorded, it cannot be removed or overwritten, though more data can sometimes be added in multiple sessions if space remains.

### Q: When was the CD-R format introduced?
A: The format was officially published on June 13, 1988.

## Why It Matters
The CD-R represents a critical evolution in digital storage, transitioning optical media from a read-only distribution medium to a consumer-grade recording technology. By adapting the Compact Disc—originally designed by Philips and Sony to replace vinyl records—the CD-R democratized data archiving and audio mastering. It allowed users to create "perfect digital copies" of data and audio without the degradation associated with magnetic tape formats like cassettes. This capability transformed how individuals and businesses backed up data, distributed software, and compiled music, establishing a new standard for personal data storage before the rise of USB drives and cloud computing.

## Notable For
-   Being the primary recordable version of the world's first widely successful digital optical storage format.
-   Enabling "Write Once, Read Many" (WORM) functionality for consumer and archival purposes.
-   Maintaining the physical 120mm diameter standard established by the original Compact Disc.
-   Being governed by the "Orange Book" standard within the Rainbow Books specifications.
-   Having a vast global presence, with Wikipedia articles in over 30 languages including Japanese, German, French, and Chinese.

## Body

### Definition and Function
CD-R stands for Compact Disc Recordable. It is defined as a compact disc format that can be written once and read arbitrarily many times. It is a subclass of both the compact disc and the machine-readable medium. Unlike mass-produced CDs which are physically pressed with pits, CD-Rs use a photosensitive organic dye layer to record data. Once recorded, the disc behaves like a standard Compact Disc and can be read by most CD players and drives.

### Development and Invention
The CD-R format was a direct extension of the Compact Disc technology originally developed by Philips and Sony in 1979. While the Compact Disc was created to replace vinyl records and cassettes, the CD-R was developed to provide recordability.

-   **Inventors:** The technology is credited to **Taiyo Yuden**, **Koninklijke Philips NV**, and **Sony Group**.
-   **Timeline:** The format was formally published on **June 13, 1988**.
-   **Context:** This development occurred after the 1982 release of the first audio CD and alongside the evolution of other formats like CD-ROM.

### Technical Specifications
The CD-R adheres to the physical and logical standards established by the parent Compact Disc format to ensure compatibility.
-   **Physical Structure:** The discs utilize a 1.2mm thick polycarbonate plastic substrate. They typically follow the 120mm diameter standard, though variations like the Mini CD (80mm) and business card CD exist.
-   **Data Encoding:** Data is read using a 780nm wavelength laser. The recording process involves the laser heating the dye layer to create marks that simulate the "pits" found on a pressed disc.
-   **Capacity:** A standard disc holds up to **700 megabytes** of data, which translates to roughly 80 minutes of audio using the Compact Disc Digital Audio format (16-bit resolution, 44.1 kHz sampling rate).
-   **Standards:** The technical specifications are outlined in the **Orange Book** (part of the Rainbow Books series) and **ECMA-394**.

### Related Formats and Evolution
CD-R is part of a broader ecosystem of optical disc technologies:
-   **Parent:** It is a direct derivative of the **Compact Disc**.
-   **Counterparts:** It coexists with **CD-ROM** (read-only memory) and **CD-RW** (rewritable, which allows data to be erased and rewritten).
-   **Successors:** The technology paved the way for higher capacity recordable formats like DVD and Blu-ray, which inherited the 120mm form factor and similar recording principles.

### Identification and Identifiers
The entity is recognized across multiple knowledge bases and standards organizations:
-   **Wikidata ID:** Q15172 (via Compact Disc parent link) / specific CD-R entries exist.
-   **Encyclopædia Britannica ID:** topic/CD-Recordable-disc
-   **FOLDOC ID:** Compact+Disc+Recordable
-   **Microsoft Academic ID:** 2910943904 (discontinued)
-   **Art & Architecture Thesaurus ID:** 300266409

## References

1. [Source](https://www.edocpublish.com/resources-2/history-of-taiyo-yuden-cd-r/)
2. Freebase Data Dumps. 2013
3. YSO-Wikidata mapping project
4. KBpedia
5. Wikibase TDKIV