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DVD recordable and DVD rewritable are a collection of optical disc formats that can be written to by a DVD recorder and by computers using a DVD writer. The "recordable" discs are write-once read-many (WORM) media, where as "rewritable" discs are able to be erased and rewritten. Data is written ('burned') to the disc by a laser, rather than the data being 'pressed' onto the disc during manufacture, like a DVD-ROM. Pressing is used in mass production, primarily for the distribution of home video.
DVD±R (also DVD+/-R, or "DVD plus/dash R") is a shorthand term for both DVD+R and DVD-R formats. Likewise, the term DVD±RW refers to both rewritable disc types, the DVD+RW and the DVD-RW. DVD±R/W (also written as, DVD±R/RW, DVD±R/±RW, DVD+/-RW, DVD±R(W) and other arbitrary ways) handles all common writable disc types, but not DVD-RAM.[1] A drive that supports writing to all these disc types including DVD-RAM (but not necessarily including cartridges or 8cm diameter discs) is referred to as a "Multi" recorder.[2]
Like CD-Rs, DVD recordable uses dye to store the data. During the burning of a single bit, the laser's intensity affects the reflective properties of the burned dye. By varying the laser intensity quickly, high density data is written in precise tracks. Since written tracks are made of darkened dye, the data side of a recordable DVD has a distinct color. Burned DVDs have a higher failure-to-read rate than pressed DVDs, due to differences in the reflective properties of dye compared to the aluminum substrate of pressed discs.
- ^ "DVD QA", Technology, Osta.
- ^ Understanding DVD - Physical Compatibility - Optical Storage Technology Association