Optical Disc Archive Optical Disc Archive Optical Disc Archive is a storage technology that was introduced by the Sony Corporation. It uses removable cartridges, where each cartridge holds 12 optical discs. Each of the internal optical discs is similar to, but not compatible with, a Blu-ray disc. The latest version of the cartridge, that has a total capacity of about 3.3TB, uses discs that hold about 300GB each. The technology was publicly announced on 16 April 2012 during the NAB Show with the first units shipping in February 2013. Generation 2 of the Optical Disc Archive technology is scheduled for mid-2016. Generation 2
DVD-RAM The on-disc structure of DVD-RAM is closely related to hard disk and floppy disk technology, as it stores data in concentric tracks. DVD-RAMs can be accessed just like a hard or floppy disk and usually without any special software. DVD-RWs and DVD+RWs, on the other hand, store data in one long spiral track and require special packet reading/writing software to read and write data discs. Like magneto-optical (MO) technologies, DVD-RAM has numerous rectangles on the disc surface that define the boundaries of data sectors. However, DVD-RAM is not MO but a phase transition medium, similar to CD-RW, DVD-RW, or DVD+RW.