DVD recordable higher-capacity formats like Blu-ray and HD DVD. A double-layer DVD+RW specification was approved in March 2006 with a capacity of 8.5 GB. However, manufacturing support for these rewritable dual-layer discs did not materialize due to costs and expected competition from newer and higher-capacity formats like Blu-ray and HD DVD. DVD recordable DVD recordable and DVD rewritable are optical disc recording technologies. DVD optical disc formats that can be recorded by a DVD recorder, (written, “burned”), either write once or rewritable (write multiple times) format written by laser, as compared to DVD-ROM, which is technically mass-produced by pressing, primarily for the
Optical disc corresponding disc player. For computer data backup and physical data transfer, optical discs such as CDs and DVDs are gradually being replaced with faster, smaller solid-state devices, especially the USB flash drive. This trend is expected to continue as USB flash drives continue to increase in capacity and drop in price. Additionally, music purchased or shared over the Internet has significantly reduced the number of audio CDs sold annually. The first recorded historical use of an optical disc was in 1884 when Alexander Graham Bell, Chichester Bell and Charles Sumner Tainter recorded sound on a glass disc using a beam