Daniel, the BD layers are still at around .1mm if there are 1,2 or 8 layer is just a few microns , if I am not mistaken the deepest one is at .1mm

Yes the disk ids DS with HD DVD (or DVD) on one side and BD on the other. Mike talked about a triple type and asked if BD would be the issue. I was just pointing out that DL HD DVD and DL DVD cannot happen on one of these. It can be DL HD DEVD, DL DVD or one of each. In theory it could happen but either HD DVD or DVD players would need to be redefined to make sure the laser does not have issues with the BD layers.



in theory if that image was to scale it would just be showing .5mm-.7mm the 2l BD@.1mm should be OK. So a 2BDx2HD DVDx2DVD should in theory work (the same way as JVCs SS 2BDx2 DVD but the tolerance for the under layer (DVD in that case) in players must be good enough to play the disks (for JVCs BD/DVD I think it played well in 90% of players tested)

as for focus - dual players- I don't think it is an issue. For example the PS3 is a single lens OPU and it focuses IR to 1.2mm, red to .6mm and blue to .1. I think the biggest issue would be intelligence. How and how long would it take to determine what type of disk it is? what if someone makes (2x2)x2 disks (DL BD and DL HD DVD on the same side and DL DVD on the other) how will a dual player know to go with BD or HD DVD