"...Yamaha Europe has fired up a page with all the technical details, which new CRW2100x models use. Terms like Pure Phase Laser System, Partial CAV and Pure Phase Laser System explained there. Here is an interesting snip:

- Partial CAV
"...The CRW2100S drive uses CAV method in the inner portions as well as CLV method in the outer portions (Partial CAV) in order to enable up to 16X-speed writing. The drive will control the disc rotation speed to start writing at 12X speed in the inner portions, gradually accelerating up to 16X speed and maintaining 16X speed in the outer portions..."