DVD CDs (0.74 µm for DVD versus 1.6 µm for CD), accounting in part for DVD's increased storage capacity. In comparison, Blu-ray Disc, the successor to the DVD format, uses a wavelength of 405 nm (violet), and one dual-layer disc has a 50 GB storage capacity. Read and write speeds for the first DVD drives and players were 1,385 kB/s (1,353 KiB/s); this speed is usually called "1×". More recent models, at 18× or 20×, have 18 or 20 times that speed. Note that for CD drives, 1× means 153.6 kB/s (150 KiB/s), about one-ninth as swift. DVD-Video is a standard
Professional Disc Professional Disc Professional Disc (PFD) is a digital recording optical disc format introduced by Sony in 2003 primarily for XDCAM, its new tapeless camcorder system. It was one of the first optical formats to utilize a blue laser, which allowed for a higher density of data to be stored on optical media compared to infrared laser technology used in the CD and red laser technology used in the DVD format. PFD uses a 405 nm wavelength and a numerical aperture (NA) of 0.85 for the laser, allowing 23 GB of data to be stored on one 12 cm disc –