HD DVD HD DVD HD DVD (short for High Definition Digital Versatile Disc) is a discontinued high-density optical disc format for storing data and playback of high-definition video. Supported principally by Toshiba, HD DVD was envisioned to be the successor to the standard DVD format. On 19 February 2008, after a protracted format war with rival Blu-ray, Toshiba abandoned the format, announcing it would no longer manufacture HD DVD players and drives. The HD DVD Promotion Group was dissolved on March 28, 2008. The HD DVD physical disc specifications (but not the codecs) were still in use as the basis for the
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.