Editing Optical disc (section)

===Fourth-generation===
The following formats go beyond the current third-generation discs and have the potential to hold more than one terabyte (1 [[Terabyte|TB]]) of data and at least some are meant for cold [[computer data storage|data storage]] in [[data centers]]:<ref>{{Cite web |title=Sony Everspan Optical Disc Data Archive System Ready For IoT |url=http://www.hughsnews.ca/sony-everspan-optical-disc-data-archive-system-ready-for-iot-0056191 |access-date=2023-03-02 |website=www.hughsnews.ca |archive-date=2023-06-05 |archive-url=https://web.archive.org/web/20230605104244/http://www.hughsnews.ca/sony-everspan-optical-disc-data-archive-system-ready-for-iot-0056191 |url-status=live }}</ref>{{dubious|date=May 2020}}
* [[Archival Disc]]
* [[Holographic Versatile Disc]]
Announced but not released:
* [[LS-R]]
* Protein-coated disc
* [[Stacked Volumetric Optical Disc]]
* 5D DVD
* [[3D optical data storage]] (not a single technology, examples are [[Hyper CD-ROM]] and [[Fluorescent Multilayer Disc]])

In 2004, development of the [[Holographic Versatile Disc]] (HVD) commenced, which promised the storage of several terabytes of data per disc. However, development stagnated towards the late 2000s due to lack of funding.

In 2006, it was reported that Japanese researchers developed ultraviolet ray lasers with a wavelength of 210 nanometers, which would enable a higher [[bit]] density than Blu-ray discs.<ref>{{Cite web |last=Kleiner |first=Kurt |date=17 May 2006 |title=Ultraviolet LED may boost disc capacity |url=https://www.newscientist.com/article/dn9183-ultraviolet-led-may-boost-disc-capacity/ |access-date=2022-04-18 |website=New Scientist |language=en-US |archive-date=2022-04-18 |archive-url=https://web.archive.org/web/20220418211948/https://www.newscientist.com/article/dn9183-ultraviolet-led-may-boost-disc-capacity/ |url-status=live }}</ref> As of 2022, no updates on that project have been reported.