[QUOTE=Tyreksionibus;689846]Let’s suppose I have a DVD+R DL disk and I DO [U]NOT[/U] change the booktype to DVD-ROM. If the drive didn’t read it would it do that deliberately and ONLY because it is not a supported type (so would it be a virtual problem)? I thought DL disks needed a special laser. Is it right ? On some sites I have seen burning DL disks require 2 separate lasers, one for writing on the first reflective layer and the other for writing on the second hemi-reflective layer.[/QUOTE]
As G@M3FR3@K said all drives can read DL ROMs it’s in the DVDV Specs for players to support it.
Well it’s actually a bit of a “trick” to change the booktype to DVD-ROM. Actually what you’re doing is adding to the leadin track that is pre-recorded on -R discs (spath expalined this on here before).
The booktype is still what it is, but the second part in that leadin change it so some drives will think it’s a ROM but they still have to support the recordable format. I don’t think old drives/players that have no support for any -R discs can be fooled.
I never heard about a second laser needed for DL, if that was true then firmware that updated SL writers for DL would not be possible, so I it doesn’t sound reliable to me.