The capacity of optical secondary storage varies significantly depending on the type of disc used, ranging from hundreds of megabytes to over a hundred gigabytes.
Optical storage media, such as CDs, DVDs, and Blu-rays, are commonly used for storing various forms of digital data, including music, video, games, software, and data backups. Their capacity makes them suitable for distributing or archiving large files.
Based on common formats:
- CDs (Compact Discs): Primarily designed for audio, CDs can store approximately 700 megabytes (MB) of data.
- DVDs (Digital Versatile Discs): Offering significantly more capacity than CDs, standard single-layer DVDs can hold 4.7 gigabytes (GB). Dual-layer DVDs increase this capacity to about 8.5 GB.
- Blu-rays: Representing the high-capacity end of consumer optical media, single-layer Blu-ray discs store 25 GB. Dual-layer discs double this to 50 GB, and specialized formats like BDXL can hold 100 GB or even 128 GB.
Here is a summary of typical capacities:
| Optical Media Type | Approximate Capacity (Single Layer) | Approximate Capacity (Dual Layer / BDXL) | Common Usage Examples |
|---|---|---|---|
| CD | 700 MB | N/A | Music, Small Data Files |
| DVD | 4.7 GB | 8.5 - 9.4 GB | Standard Definition Video, Software |
| Blu-ray | 25 GB | 50 GB - 128 GB | High Definition Video, Games, Large Data |
These capacities highlight the evolution of optical storage, with each new format offering a substantial increase in storage space to accommodate larger and more complex digital content like high-definition movies and expansive video games.
