DVDs (Digital Versatile Discs) are compact discs designed to store a variety of data such as video, audio and multimedia files. Blank DVDs are similar to blank CDs but with a higher storage capacity, they can hold up to 13 times the information of a standard CD. The difference between R and RW is that DVD-R is a write-once recordable disc whereas the DVD-RW is a rewritable disc. Packs of blank DVDs are commonly supplied on a spindle or in a jewel case.
What are the differences?
DVD-R and DVD+R are both 120 mm in diameter with a thickness of 1.2 mm. The difference between DVD-R and DVD+R is primarily in the way they are formatted. The laser that exists within a DVD recorder uses a different technique to determine where the data is located on the disc. The DVD-R has marks that are positioned in the grooves however, the DVD+R instead measures the wobble frequency.
DVD-RAM (Random Access Memory) is used for the archival storage of data as it can hold a lot of data for a longer period of time without damage. It is also possible to write over a DVD-RAM more times than a re-writable disc.
Before writing anything to a DVD it should be formatted first. Formatting any disc will determine its compatibility with other devices. There are usually two options: mastered which will allow a DVD to be used in various external devices like a DVD player, and live file system which only allows the DVD to be used in the Windows operating system.
Common data storage capacities of a DVD are:
· 4.7 GB (Single sided / Single layer)
· 9.4 GB (Double sided / Single layer)
· 8.5 GB (Single sided / Dual layer)
· 17.1 GB (Double sided / Dual layer)
The speed a DVD writes information depends on the type and amount of data that is being transferred to the disc. The writing speed refers to how fast the data can be written from a hard drive to a DVD, which is not the same as real-time recording from a DVD video player. Some DVDs support speeds of up to 24x, however, a higher writing speed does result in a quicker disc burn but the quality may be lower.