Does NEC 2510a will be able to burn DVD+RW DL when media comes ?

I want to buy a NEC 2510a next week, and I wonder if I will be able to use DVD+RW DL 8 gigabytes (if that will exists, but I'm sure yes) as a big floppy or tape recorder to store safety backups ?

Well, even if they were to create a dual layer +RW I very much doubt the 2510a will be able to write to it. MAYBE with a firmware upgrade, but, I'd not count on this at all. To answer your question, though, yes, if you could theoretically write to a dual layer rewritable you could use it for backups.

First search for discussions on DVD+RW DL on the forum menu. Or read what Mod M. Spath has said about it.

It will be extremely unlikely to see DVD+RW DL media being sold at affordable cost actually. Has anyone bought more than 1,000 32x CD-RW media for personal use? DVD+RW DL will have an even harder time, even if made commercial.

Verbatim has already said that we will not never see DVD+RW DL because they do not succeed to catch up 18% of index of reflection for being read without difficulty.