DVD 9, DVD 5, Dual Layer DVD, what do these mean?
A list of general DVD formats.

DVD+R
DVD+Recordable defines a standard for recordable DVD drives and media defined by the DVDRW Alliance. Often called "plus R", the format is write once (compared to DVD+RW wich can be erased and rewritten). The single sided discs can hold 4,700,000,000 bytes (4.38 Gigabytes at 1024 bytes to the kilobyte) with double sided discs holding twice as much. There are no dual layer single sided recordable discs. This format competes with the DVD Forum DVD-R specification.



DVD+R DL
DVD+R DL or called DVD+R9 is a Dual Layer writeable DVD+R. The dual layered discs can hold 7.95 GB or around 8 540 000 000 bytes (called DVD-9) and a double sided dual layered disc 15.9 GB or around 17 080 000 000 bytes (called DVD-18).


DVD+RW
DVD+RW is a ReWriteable media format of the DVD+R standard.


DVD-10
DVD-10 is a double sided single layer DVD which can fit up to 9.4 GB or 8.7 computer GB. Video DVD, DVD-R/W and DVD+R/W supports this format.



DVD-18
DVD-18 is a double sided dual layer DVD which can fit up to 17 GB or 15.9 computer GB which some commercial video DVDs are using today (a DVD-18 is basicly four pressed plastic DVD-5s pressed together, they are not burned). Video DVD supports this format but DVD-R/W and DVD+R/W does not support this format.



DVD-5
DVD-5 is a single sided single layer DVD that stores up to about 4.7 GB = 4 700 000 000 bytes and that is 4.38 computer GigaBytes where 1 kilobyte is 1024 bytes(4 700 000 000B/1024 = about 4 589 843KB/1024 = about 4485MB/1024 = about 4.38GB) . Video DVD, DVD-R/W and DVD+R/W supports this format. Often referred to as "single sided, single layer".



DVD-9
DVD-9 is a single sided dual layer DVD which can fit up to 8.5 GB or 7.95 computer GB which many commercial video DVDs are using today (a DVD-9 is basicly two pressed plastic DVD-5s pressed together, they are not burned). Video DVD supports this format but DVD-R/W and DVD+R/W does not support this format.

DVD-R
DVD-Recordable defines a standard for recordable DVD drives and media defined by the DVD Forum. Often called "minus R", the format is write once (compared to DVD-RW wich can be erased and rewritten). The single sided discs can hold 4,700,000,000 bytes (4.38 Gigabytes at 1024 bytes to the kilobyte) with double sided discs holding twice as much. There are no dual layer single sided recordable discs. This format competes with the DVD+R format.


DVD-R DL
DVD-R DL or called DVD-R9 is a Dual Layer writeable DVD-R. The dual layered discs can hold 7.95 GB or around 8 540 000 000 bytes (called DVD-9) and a double sided dual layered disc 15.9 GB or around 17 080 000 000 bytes (called DVD-18).



DVD-RAM
A recordable format supported by the DVD Forum. It has superior recording features but it is not compatible with most DVD-ROM drives or DVD Video players. It works well when set up like a removable hard disk.


DVD-RW
DVD-RW is a ReWriteable media format of the DVD-R standard.