HD DVD-R is a recordable version of the HD DVD optical disc format. Like DVD-R, HD DVD-R is a write-once media and so written data cannot be erased from the disc. HD DVD-R comes in two variants; single layer, which can store up to 15GB of data and dual layer, which can store up to 30GB of data. At the current time (July 2007), HD DVD burners are in general, more scarcely used than their Blu-ray disc counterparts.
HD DVD-RAM is another writeable version of the HD DVD optical disc format.
