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 maximum speed (56× for CDs or around 18× in the case of DVDs) at which drives can operate. Current optical drives use either a "tray-loading" mechanism, where the disc is loaded onto a motorized or manually operated tray, or a "slot-loading" mechanism, where the disc is slid into a slot and drawn in by motorized rollers. With both types of mechanism, if a CD or DVD is left in the drive after the computer is turned off, the disc cannot be ejected using the normal eject mechanism of the drive. However, tray-loading drives account for this situation by providing a