The M-DISC is an extremely durable and reliable storage medium that enables permanent data archiving. It is the only disc to have passed the stringent long-term archiving tests of the U.S. Department of Defense. Thanks to its patented stone-like material, data is literally engraved into the recording layer. This physical change in the medium allows the stored content to be archived for up to 1,000 years. The inorganic layer also ensures that no special precautions are needed during storage, as it is unaffected by temperature, humidity, or sunlight. M-DISC BD-R XL media can be written to and read by all Blu-ray BD-XL recorders.