Older DVD drives can't read dual layer disks

There are some dual-layer movies that won't play on my DVD-ROM equipped G3 iBook. The G3 also won't mount a dual-layer Tiger DVD. Turns out this is probably an aging defect. Originally these drivers were supposed to be able to read dual-layer DVDs, but over time they may lose that ability -- I suspect the problem is exacerbated by changes in disk manufacturing:

Macintouch: iLife 06

Antonio Tejada

Sebastian Kempgen mentioned that "...the iLife 06 DVD requires a drive which can read double-layer discs. However, the DVD drives of older PowerMacs such as a G4 MDD cannot read double-layer discs - the Install DVD simply does not mount. ..."

That is plain and simply a faulty drive. Apple doesn't specify a dual-layer capable DVD drive because dual-layer discs are part of the core DVD specification: all DVD readers are required to be capable of reading them, without exception. Dual-layer DVDs are not a recent addition to the spec -- it's been there from the beginning. Only the ability to burn them yourself is new (and as with any burned disc, read compatibility of burned dual-layer discs is lower than that of pressed discs).

I have found that the DVD-ROM drives from G3s and G4s do not age well -- they lose the ability to read even remotely marginal discs, and even occasionally reject entirely suitable discs. That is likely the case here.