Question: what is dvd 5 and 9?
Answer: DVD-9 discs are one-sided, double layer recordable DVDs with a capacity of 8.5GB. The numbering after DVDs can be approximated to the capacity of the discs. For example DVD-5 discs can hold 4.7GB on a one-sided, single layer disc and DVD-18 can hold 17.4GB on a dual-side, dual-layer disc.