HD DVD May 2008, both companies announced they would stop manufacturing dual-compatibility drives. A few computer manufacturers (such as HP and Acer) sold computers with combination HD DVD/Blu-ray Disc drives. LG marketed a Blu-ray writer that also read HD DVD discs (but could not write to them). HD DVD competed primarily with Blu-ray Disc. Both formats were designed as successors to DVD, capable of higher quality video and audio playback, and of greater capacity when used to store video, audio, and computer data. Blu-ray Disc and HD DVD share most of the same methods of encoding media onto discs with each other,
Optical disc drive on personal computers was originally a batch-oriented task in that it required specialised authoring software to create an "image" of the data to record, and to record it to disc in the one session. This was acceptable for archival purposes, but limited the general convenience of CD-R and CD-RW discs as a removable storage medium. Packet writing is a scheme in which the recorder writes incrementally to disc in short bursts, or packets. Sequential packet writing fills the disc with packets from bottom up. To make it readable in CD-ROM and DVD-ROM drives, the disc can be "closed" at any