HVD

HVD

High Voltage Differential

HVD

(1) (High Voltage Differential) See SCSI and differential signaling.

(2) (Holographic Versatile Disc) A high-capacity optical disc from the HVD Forum (www.hvd-forum.org) that combines single beam holographic storage and DVD technologies to provide cartridge capacities reaching 1TB and beyond. Formed in 2005 as the HVD Alliance, the first HVD standards were released in 2007 for 100GB read-only (ECMA-378) and 200GB recordable (ECMA-377) formats.

HVD uses the conventional CD/DVD pit layer for addressing the disc, on top of which is the holographic recording layer. A red laser reads the addresses, while a green or blue laser reads and writes the holograms.

Single Beam Holography
Throughout the history of holographic storage research, two separate laser beams have been used to write the holograms at the intersecting point. Using Optware's Collinear Holography, HVD combines the two lasers into one lens, which reduces the size and cost of the mechanism. See holographic storage.

Layers in an HVD Disc