The difference: There’s DVD+R, DVD+RW, DVD-R, DVD-RW, and even DVD-ROM!
Let’s first start with the most obvious difference: some have R and some have RW. The “R” stands for recordable, while the “W” stands for rewriteable.
The main difference between DVD-R and DVD-RW, or DVD+R and DVD+RW is that the R disc formats can only be written to once, and then it is only readable and can’t be erased for the rest of its digital life. While RW discs are can be written to and erased many times, they are both readable and writeable.
“R” discs are perfect if they are only needed to be written to once, such as giving some files to a friend or transferring them between PCs. “RW” discs have their strength in the ability to be used many times over, which is great for routine system backups, etc. And naturally, the RW discs are slightly more expensive than the R discs, but you’ll have to decide if the trade offs are worth the money.
Now, onto the difference between DVD-R and DVD+R. As I just described above, DVD-R & DVD-RW are sister discs, the difference being one is writeable once, while the other is writeable multiple times. The same thing is true for DVD+R & DVD+RW.
But what’s the difference between the plus and minus?
On “minus“ discs (-R, -RW) can only be written to in one layer on the discs surface.
(+R, +RW): These discs can be written to in multiple layers, giving them slightly better and more disc storage than the “minus“ format. Because of this additional capacity, they are slightly more expensive than “minus“ discs.
The last clarification: the difference between DVD-ROM and DVD+RW, or the other DVD formats I mentioned above. The DVD-ROM drive can only read DVDs, while the other DVD drives can read and write data to DVDs.
All above apply to CD's.
What is the difference between DVD and CD?
The capacity.
DVD is a high capacity multimedia data storage medium. It can accommodate a complete movie on a single disc, content rich multimedia or very high quality multi-channel audio.
DVD disks can hold many times the data that a CD can.
CDs can hold around 650 megabytes (MB). DVDs can hold 4.7 gigabytes (GB) or about 4,700 MB.
Hope it helps
As of storage of your data, please read other users opinion.