BD-RE is the erasable blu ray disc format. This type of media can also be referred to as a rewriteable format and is comparable to the CD-RW, DVD-RW, and DVD+RW formats except that the blu ray version provides more storage capacity and requires a blue laser to be able to record to the disc and read the disc.
This type of media is purchased blank. Information can be recorded to the disc but unlike the BD-R, this disc can be erased and reused.
There is a limit as to how many times the disc can be erased, but for most discs they can be reused a minimum of 1000 times, which for most cases is much more than is required during standard use. Some may be erasable for up to 10,000 times.
This format comes in the 8 cm (3.25 inches) diameter size and the 12 cm (4.75 inches) size. It can have one, two, or three layers that can store information. The three data layer disc is known as the XL disc, has the TL designation, and was introduced in 2010. The capacities of the various BD-RE discs are provided below:
The rewriteable or erasable layer of this type of disc is a phase change alloy. It is similar to what is used in CD-RWs, DVD-RWs, and DVD+RWs. The erasable CDs and DVDs have shown moderate to low stability respectively. Therefore, although manufacturers are claiming lifetimes of up to 200 years, it is speculated that at best these disc will only have moderate longevity. More scientific research is required in order to determine how stable these discs are relative to other optical disc media.
BD-REs should be stored in standard jewel cases in standard room temperature conditions. Cooler and drier (within reason) are better conditions for storage. Warm or hot and humid conditions should be avoided. Do not write on the surfaces of these discs. Do not place adhesive labels on these discs.
The erasable blu ray disc format is fairly new and provides very good storage capacity. However, due to the fact that it is not widely accepted in the marketplace at the moment, has a questionable stability, and is erasable, this format should not be used for the long-term storage of important digital files.