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Although the LaserDisc format was supplanted by DVD by the late 1990s, many LaserDisc titles are still highly coveted [39] by movie enthusiasts (for example, Disney's Song of the South which is unavailable in the US in any format, but was issued in Japan on LaserDisc.) This is largely because there are many films that are still only available ...
Laserdisc technology, using a transparent disc, [1] was invented by David Paul Gregg in 1958 (and patented in 1970 and 1990). [2] [3] By 1969 Philips had developed a videodisc in reflective mode, which has great advantages over the transparent mode. MCA and Philips decided to join their efforts. They first publicly demonstrated the videodisc in ...
Packet writing is a technology that allows optical discs to be used in a similar manner to a floppy disk. Packet writing can be used both with once-writeable media and rewriteable media. Several competing and incompatible packet writing disk formats have been developed, including DirectCD and InCD.
Media technologies vary, for example, M-DISC media uses a rock-like layer to retain data for longer than conventional recordable media. While being read-only compatible with existing DVD and Blu-ray drives, M-DISC media can only be written to using a stronger laser specifically made for this purpose, which is built into fewer optical drive models.
The compact disc is an evolution of LaserDisc technology, [10] where a focused laser beam is used that enables the high information density required for high-quality digital audio signals. Unlike the prior art by Optophonie and James Russell, the information on the disc is read from a reflective layer using a laser as a light source through a ...
It was the introduction of semiconductor lasers that provided the technology needed to make optical storage more practical in both storage density and cost terms. Prices fell to the point that they could be used in consumer products, leading to the 1978 introduction of the analog LaserDisc format.
The first laser disc, demonstrated in 1972, was the Laservision 12-inch video disc. The video signal was stored as an analog format like a video cassette. The first digitally recorded optical disc was a 5-inch audio compact disc (CD) in a read-only format created by Sony and Philips in 1975. [53]
Current optical data storage media, such as the CD and DVD store data as a series of reflective marks on an internal surface of a disc. In order to increase storage capacity, it is possible for discs to hold two or even more of these data layers, but their number is severely limited since the addressing laser interacts with every layer that it passes through on the way to and from the ...