# CD-RW

> compact disc format that can be erased and rewritten

**Wikidata**: [Q203638](https://www.wikidata.org/wiki/Q203638)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/CD-RW)  
**Source**: https://4ort.xyz/entity/cd-rw

## Summary  
CD‑RW (Compact Disc ReWritable) is a rewritable optical disc format introduced in 1997. It belongs to the compact disc family and can be erased and rewritten multiple times using a phase‑change alloy coating.

## Key Facts  
- **Introduced:** 1997 (publication date)【source】  
- **Format type:** Rewritable compact disc (CD‑RW)【source】  
- **Classification:** Instance of *product*; subclass of *compact disc*【source】  
- **Material composition:** Polycarbonate substrate with a coating of the phase‑change alloy AgInSbTe【source】  
- **Standard/alias:** Also known as “Orange Book” and “Compact Disc Eraseable”【source】  
- **Successors:** Followed by DVD‑RW and DVD+RW optical disc formats【source】  
- **Icon & image:** Icon – `https://commons.wikimedia.org/wiki/Special:FilePath/Cdwriter_unmount.png`; Example image – `https://commons.wikimedia.org/wiki/Special:FilePath/Philips_700MB_80min_CD-RW_20060724.jpg`【source】  
- **Wikidata description:** “compact disc format that can be erased and rewritten”【source】  
- **Wikipedia presence:** Article titled *CD‑RW* available in 12 languages (e.g., en, de, es, fr)【source】

## FAQs  
### Q: What does CD‑RW stand for?  
A: CD‑RW stands for **Compact Disc ReWritable**, a disc that can be erased and recorded again.  

### Q: When was the CD‑RW format released?  
A: The CD‑RW format was first published in **1997**.  

### Q: Which optical disc formats succeeded CD‑RW?  
A: CD‑RW was succeeded by the rewritable DVD formats **DVD‑RW** and **DVD+RW**.  

### Q: What material allows CD‑RW discs to be rewritten?  
A: CD‑RW discs use a **phase‑change alloy coating of AgInSbTe** applied to a polycarbonate base, enabling erasing and rewriting.  

### Q: Is CD‑RW part of the same family as regular CDs?  
A: Yes, CD‑RW is a **subclass of the compact disc** family, sharing the same physical dimensions but adding rewritable capability.  

## Why It Matters  
CD‑RW introduced a practical way to reuse optical media, reducing the need for disposable write‑once CDs and lowering storage costs for consumers and businesses. By employing a phase‑change alloy (AgInSbTe) that can be toggled between amorphous and crystalline states with laser heating, the format allowed data to be erased and rewritten many times without altering the disc’s physical structure. This capability paved the way for more flexible data backup strategies and influenced the design of later rewritable optical formats such as DVD‑RW and DVD+RW. Although newer storage technologies have largely supplanted optical media, CD‑RW remains a notable milestone in the evolution of removable digital storage, illustrating how material science and optical engineering combined to extend the lifespan of a ubiquitous format.  

## Notable For  
- **First rewritable CD standard** – introduced the “Orange Book” specification for rewritable optical discs.  
- **Phase‑change technology** – uses an AgInSbTe coating that can be repeatedly switched between states with a laser.  
- **Compatibility** – retains the physical dimensions of standard CDs, allowing use in existing CD drives (read‑only).  
- **Transition role** – served as the bridge between write‑once CDs and later rewritable DVD formats (DVD‑RW, DVD+RW).  
- **Broad recognition** – listed under multiple aliases (e.g., CD‑E, ECMA‑395) and referenced across 12 Wikipedia language editions.  

## Body  

### Overview  
CD‑RW (Compact Disc ReWritable) is an optical disc format that extends the original compact disc (CD) technology by adding the ability to erase and rewrite data. It is classified as a *product* and a *subclass of compact disc* in Wikidata. The format was officially published in **1997**.

### Technical Specifications  

- **Physical structure:** Identical diameter and thickness to standard CDs, built on a polycarbonate substrate.  
- **Rewritable layer:** Coated with a phase‑change alloy **AgInSbTe** (silver‑indium‑antimony‑tellurium). The alloy changes between amorphous and crystalline states when heated by a laser, enabling data erasure and rewriting.  
- **Standard identifiers:** Known by several aliases, including *Orange Book*, *Compact Disc Eraseable*, *CD‑E*, and *ECMA‑395*.  

### Historical Context  

- **Parent technology:** Derives from the broader *compact disc* family, which originated in **1979**.  
- **Predecessors and successors:** While CD‑RW follows the original CD format, it was later succeeded by rewritable DVD formats **DVD‑RW** and **DVD+RW**, reflecting the industry’s shift toward higher‑capacity optical media.  

### Materials and Manufacturing  

- **Substrate material:** Polycarbonate, providing structural integrity and optical clarity.  
- **Rewritable coating:** AgInSbTe, a phase‑change material that allows multiple rewrite cycles without physical degradation of the disc surface.  

### Adoption and Legacy  

- **Industry impact:** CD‑RW enabled users to reuse optical media, reducing waste and cost for data backup and distribution.  
- **Legacy:** Its rewritable technology informed the development of later optical standards, notably the DVD‑RW family, and contributed to the broader acceptance of reusable digital storage media.  

### References and Media  

- **Icon:** `https://commons.wikimedia.org/wiki/Special:FilePath/Cdwriter_unmount.png`  
- **Example image:** `https://commons.wikimedia.org/wiki/Special:FilePath/Philips_700MB_80min_CD-RW_20060724.jpg`  

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*All information presented above is drawn exclusively from the supplied source material.*

## References

1. Freebase Data Dumps. 2013
2. KBpedia
3. Wikibase TDKIV