Over the years, optical drives have evolved to be compatible with a wide variety of formats, such as DVD-R and DVD+R. While most drives now incorporate all of the major formats, there are still some differences, such as dual-layer and single-layer drives.
DVD Layer Basics
Information on a DVD is stored on it by using a laser to etch microscopic pits on a layer. It is digital, which means that a pit translates to a "1," and a smooth surface translates to a "0."
A standard DVD can store up to 4.7 gigabytes of information (compared to a floppy disk, which can contain 1.44 megabytes). A gigabyte is 1,024 megabytes.
A DVD with multiple layers can contain twice as much space as a single layer drive--up to 8.5 gigabytes.
Not all single-layer drives can read a dual-layer disc, but a dual-layer drive can read almost all single-layer discs.
A dual-layer drive contains more complex internal components, so it will be more expensive than a comparable single-layer drive. Blank dual-layer discs are also more expensive than single-layer discs.
- Photo Credit Zedcor Wholly Owned/PhotoObjects.net/Getty Images
About Dual Layer DVDs
As the ability to burn DVD media becomes widely available, it is natural to have questions about the wide variety of formats....