# DVD-R

> write-once, read-many form of DVD

**Wikidata**: [Q1071697](https://www.wikidata.org/wiki/Q1071697)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/DVD-R)  
**Source**: https://4ort.xyz/entity/dvd-r

## Summary
DVD-R is a "write once, read many" (WORM) form of Digital Versatile Disc that allows end users to record data. Unlike rewritable formats, information written to a DVD-R cannot be modified, making it a distinct class of DVD recordable media. Standard single-layer discs have a capacity of approximately 4.7 billion bytes.

## Key Facts
- **Classification:** DVD-R is a subclass of "DVD recordable" and operates on the "write once read many" (WORM) principle, meaning data cannot be altered once written.
- **Capacity:** The standard capacity for a single-layer (SL) DVD-R is 4,707,319,808 bytes (often marketed as 4.7 GB).
- **Structure:** A standard disc contains 2,298,496 sectors.
- **Appearance:** The recording surface of a DVD-R is characteristically purple.
- **Media Type:** It is a data storage device writable by end users, distinct from mass-produced read-only DVDs.
- **Identifiers:** The entity has a Freebase ID of `/m/024kj8` and a TDKIV term ID of `000000861`.

## FAQs
### Q: Can I erase or rewrite files on a DVD-R?
A: No. As a "write once read many" device, data written to a DVD-R is permanent and cannot be modified or erased.

### Q: What is the exact storage size of a standard DVD-R?
A: A standard DVD-R has a capacity of 4,707,319,808 bytes, which is organized into 2,298,496 sectors. Manufacturers often round this to 4.7 GB.

### Q: Why do DVD-R discs look purple?
A: The recording dye used in DVD-R media results in a distinct purple color on the disc's recording surface.

## Why It Matters
DVD-R represents a critical evolution in optical media technology, bridging the gap between read-only commercial media and the need for high-capacity, user-generated archival storage. By offering a "write once" solution, it provided a reliable method for data backup and distribution where data integrity is paramount; because the data cannot be modified after writing, the risk of accidental erasure or alteration is eliminated. This made it a standard for physical media distribution and long-term storage before cloud solutions became ubiquitous. The format standardized a capacity of roughly 4.7 GB, a significant increase over previous CD technology, allowing for the storage of larger files and higher-quality video content by end users.

## Notable For
- **Data Permanence:** Being a "write once" medium, it ensures that archived data remains unaltered, distinguishing it from rewritable formats like DVD-RW.
- **Specific Capacity:** It is notable for its specific sector count of 2,298,496, which dictates its real-world capacity of 4,707,319,808 bytes.
- **Visual Distinction:** The medium is physically distinguished by its purple recording surface.
- **User Writability:** It is a primary format within the "DVD recordable" class, enabling direct recording by consumers.

## Body
### Definition and Classification
DVD-R (Digital Versatile Disc-Recordable) is defined as a write-once, read-many (WORM) form of DVD. It falls under the broader class of **DVD recordable** devices, which encompass any Digital Versatile Disc writable by end users. The technology functions as a data storage device where information, once written, cannot be modified.

### Technical Specifications
The technical structure of a standard DVD-R is defined by precise capacity measurements and sector counts.
- **Total Capacity:** 4,707,319,808 bytes.
- **Sector Count:** 2,298,496 sectors.
- **Layers:** These specifications apply to the single-layer (SL) configuration.

While often referred to as 4.7 GB, the precise byte count highlights the distinction between decimal and binary measurement standards in storage media. Real-world capacity can vary slightly among different media manufacturers, though the sector count standard is widely observed.

### Physical Characteristics
The physical properties of the DVD-R include a distinct visual identifier.
- **Color:** The data layer of a DVD-R is purple.
- **Iconography:** The media type is represented by a specific icon (Human-gnome-dev-disc-dvdr.svg) in various computing interfaces.

## References

1. [Source](https://www.cdrom2go.com/blog/why-are-dvd-r-discs-purple)
2. [Understanding DVD - Disc Size, Configuration and Capacity](http://www.osta.org/technology/dvdqa/dvdqa6.htm)
3. Freebase Data Dumps. 2013
4. [Source](http://www.osta.org/technology/dvdqa/dvdqa6.htm)
5. Wikibase TDKIV