DVD Explained

DVD -- Originally an acronym for Digital Versatile Disc (or Digital Video Disc). A family of optical disc formats used both for prerecorded content, especially movies, and as recordable media for consumer devices and computers (that is, DVD-ROM, DVD-R, DVD-RW, DVD-RAM). A family of data format standards for video, audio, and data storage (that is, DVD-Video and DVD-Audio) for consumer electronics products and computers. DVD discs are the same diameter as CD discs (120mm. or 12 cm, in diameter), and most formats hold 4.7 GB (actually billion bytes) of data on a side. A smaller size 

mini-DVD disc is also used, especially in camcorders.

Mini-DVD -- A smaller-diameter DVD disc format, especially for use in portable camcorders. The disc diameter is 8cm (80mm), compared to 120mm (12cm) for full-size DVD discs.

Single-sided disc -- A DVD disc with data on one side. The second side is typically used for a label, like a CD disc. The storage capacity of DVD formats is 4.7 GB (actually billion bytes) per side. Also called DVD-5. See also double-sided disc, dual-layer disc.

Double-sided disc -- A DVD disc with both sides used for data storage (unlike a manufactured DVD-Video or CD Audio disc with one side used for the label). Often used to distribute two versions of a commercial movie, with a widescreen version on one side and a standard 4:3 aspect ration on the other. With both sides, the storage capacity doubles from 4.7 to 9.4 GB (actually billion bytes). Also called DVD-10. See also dual-layer disc.

Dual-layer disc -- A DVD disc with two layers of data on a side, accessed by refocusing the laser beam through the top layer to read the second layer. Often used to distribute a commercial title that is too long for a single-sided DVD while avoiding the need to continue the movie on a second disc. With the second layer, the storage capacity almost doubles from 4.7 to 8.5 GB (actually billion bytes). Also called DVD-9. See also double-sided disc.

DVD-5 -- Single-sized DVD disc format, with a storage capacity of 4.7GB (actually billion bytes).

DVD-9 -- Dual-layer DVD disc format, with a storage capacity of 8.5GB (actually billion bytes).

DVD-10 -- Double-sided DVD disc format, with a storage capacity of 9.4GB (actually billion bytes).

DLT -- Acronym for Digital Linear Tape. A half-inch magnetic tape format used extensively for computer file backup and retrieval. Commonly used for transferring premastered DVD productions to a replication facility for manufacturing.