# Digital Multilayer Disk

> the fluorescent multilayer optical disc format

**Wikidata**: [Q2657272](https://www.wikidata.org/wiki/Q2657272)  
**Wikipedia**: [English](https://en.wikipedia.org/wiki/Digital_Multilayer_Disk)  
**Source**: https://4ort.xyz/entity/digital-multilayer-disk

## Summary
Digital Multilayer Disk (DMD) is a fluorescent multilayer optical disc format used for storing binary data. As a specific instance of the optical disc class, it utilizes the standard flat, circular medium design associated with laser-readable storage technologies.

## Key Facts
- **Definition:** A fluorescent multilayer optical disc format.
- **Aliases:** Disque numerique multicouches.
- **Classification:** Instance of "optical disc" (flat, usually circular disc encoding binary data).
- **Primary Function:** Physical data distribution and long-term archival (inherited from optical disc class).
- **Wikipedia Presence:** Titled "Digital Multilayer Disk" with articles in 5 languages (English, Spanish, French, Italian, Polish).
- **Identifiers:** Freebase ID `/m/04gb8z`; BabelNet ID `00059212n` (via Optical Disc class); Library of Congress ID `sh86004405` (via Optical Disc class).
- **Sitelink Count:** 5 (specific to DMD); 54 (for the parent class Optical Disc).

## FAQs
### Q: What exactly is a Digital Multilayer Disk?
A: It is an optical disc format characterized by its use of fluorescent multilayer technology. It is classified as a type of optical disc, which is a machine-readable medium used for data storage.

### Q: How is Digital Multilayer Disk related to standard optical discs?
A: Digital Multilayer Disk is a specific instance (or subclass) of the general "optical disc" category. While standard optical discs encode data as pits and lands read by lasers, the DMD is specifically defined by its fluorescent multilayer properties.

### Q: In which languages is information about Digital Multilayer Disk available?
A: According to structured data, the entity has Wikipedia language entries in English, Spanish, French, Italian, and Polish.

## Why It Matters
Digital Multilayer Disk represents a specialized evolution within the broader optical disc ecosystem. While standard optical discs like CDs and DVDs revolutionized data distribution through the use of physical pits and lands read by lasers, formats like DMD explore advanced structures—specifically fluorescent multilayers—to potentially increase storage density and efficiency. As a member of the optical disc family, it shares the medium's core advantages: it is a removable, durable solution that does not require power to retain data, making it relevant for physical data distribution and long-term archival storage where data integrity is critical.

## Notable For
- **Fluorescent Technology:** Being explicitly defined as a "fluorescent" multilayer format, distinguishing it from standard reflective optical disc technologies.
- **Multilayer Architecture:** Utilizing multiple layers for data storage, a technique shared with high-capacity formats aimed at exceeding single-layer limitations.
- **Classification:** Being a distinct instance of optical storage media, separate from but related to major families like CD, DVD, and Blu-ray.

## Body

### Definition and Classification
The Digital Multilayer Disk (DMD) is identified as a **fluorescent multilayer optical disc format**. It is structurally classified as an **optical disc**, a category of storage media defined as flat, usually circular discs that encode binary data. These discs are primarily used for physical data distribution and long-term archival.

As an optical disc, the DMD belongs to the subclass of:
- Optical storage
- Machine-readable media
- Computer storage media
- Removable media

### Technical Context
While specific technical specifications for DMD are derived from its class definition, the underlying technology of optical discs involves encoding binary data as microscopic pits and lands on the disc's surface. A low-power laser in an optical disc drive reflects off these features, and variations in reflected light are interpreted as binary data.

Standard optical discs, the family to which DMD belongs, typically possess the following physical characteristics:
- **Shape:** Circular disk.
- **Materials:** Typically constructed using a polycarbonate substrate, a reflective layer (such as aluminum or gold), and a protective lacquer coating.
- **Sizes:** While specific DMD dimensions are not detailed in the source, the standard for the class is 120 mm in diameter, with a 80 mm "mini" version also existing.

### Identifiers and Metadata
The entity "Digital Multilayer Disk" is tracked across various knowledge bases with the following properties:
- **Wikipedia Title:** Digital Multilayer Disk
- **Wikidata Description:** "the fluorescent multilayer optical disc format"
- **Aliases:** Disque numerique multicouches
- **Freebase ID:** `/m/04gb8z`
- **Sitelink Count:** 5 (across Wikipedia languages: en, es, fr, it, pl)

### Ecosystem and Usage
As an optical disc format, DMD is part of a technology ecosystem that includes:
- **Hardware:** Optical disc drives found in computers, game consoles, and dedicated players.
- **Usage Scenarios:** Read/write operations for data distribution and archival.
- **Unicode Representation:** The general category of optical disc is represented by the symbols 💿 and 🖸.

## References

1. Freebase Data Dumps. 2013