Hehe.. it's a standard dual-layer disc. They've been making them for years. 99% of DVDs (movies, etc) produced today are dual-layer. Ever notice about halfway through a movie, it seems to pause for a split-second, then keep playing? That's the layer skip. That's also how they're able to encode over three hours of full-screen video on a single disc. Take a DVD of a TV show, for example. Each disc typically contains four episodes. That's two per layer, so each layer of the disc only contains roughtly 1.5 hours of video, maintaining high quality while still able to fit four or even five episodes on a single disc.
There's no flipping of the disc involved anymore.. the types of discs that required flipping were basically two single-layers in one disc (one on each side). The new ones are dual-layer.. two layers PER SIDE of the disc. The laser is able to focus itself "through" one of the layers to read the second layer. In fact, it's possible to have as many as four layers on one disc, if it's double-sided, dual-layer, two layers per side. It's rare, but it's been done.
Imagine two pieces of tracing paper stacked on top of each other. Each one containing a different picture. It's quite easy to see through the top piece of paper to see the image on the second, without having to remove the top piece (i.e. "flipping the disc").
Your reply couldn't have been any more blatent! Well put.
