A digital video disk (DVD) is a common media format, and an external dual layer DVD burner allows computer users to create their own disks. Most DVD burners are able to burn dual layer disks, although information related to their speed and capacity is often in the smaller print features of the drive. A dual layer DVD is a specific type of DVD media that can accept two layers of information, effectively doubling its size. An external drive is a type of computer drive that operates outside a computer, typically connected via a cable.
DVD recorders were one of the dominant forms of home high-capacity recording media for many years. These drives generally burned disks with a capacity around 4.7 gigabytes, but the specific amount varied slightly based on the disk manufacturer and the burner model. Dual layer disks have two separate write surfaces; these multiple write areas bring their average capacity up to about 8.5 gigabytes per disk. As a result of the more specific tolerances of the dual burning process, the disks typically cost more than standard disks.
An external dual layer DVD burner features a laser that varies in intensity, allowing it to write on the different layers of a dual layer disk. When the laser is at the higher intensity, it will write on the deep layer and it will write on the shallow layer with the weaker. This variable laser function is common in most modern DVD burners and readers, allowing nearly any drive to read these disks.
A common external dual layer DVD burner is made of a normal internal component within a special type of enclosure. This enclosure has anchor points to hold the drive still while it is in operation. All of the connectors that are common inside a computer are present, but they attach to a special interface that sends their signal through one of several types of cables. Most drives are powered separately from the computer and have a power cord as well.
Most external drives have several advantages over standard internal computer drives, and an external dual layer DVD burner is no different. Since the drive is not permanently attached to a computer, it may outlast a desktop system or laptop. Its portability also allows users to bring it along when they need to use an unfamiliar system; this way, they have access to the drive's functions regardless of computer. Lastly, a typical external dual layer DVD burner is powered separately from the computer itself, so it may be powered off when not in use, saving electricity.