How many layers do DVD9 discs have?

Answer by  mrandy (140)

DVD9 is dual layer disc technology. You need a special DVD burner for it, however most DVD players these days come with dual layer disc support. Such players are usually marked with "DVD-+R DL" or similar sign with letters "DL" in it.

Answer by  Alexey (31)

DVD9 discs have two layers, 4.5Gb each, on the same side of a disc. To burn DVD9 you need a dual-layer DVD writer.