Ross Walker wrote: > I think you might be confusing CAV with CLV of optical drives. > http://en.m.wikipedia.org/wiki/Constant_Angular_Velocity > no, I'm not. most HD's ('green drives' complicate this some) spin at a constant RPM, so the rotational latency is the same on the inner and outer tracks, an average of 1/2 turn, about 4mS for a 7200 rpm drive, and 2mS for a 15000rpm enterprise drive . However, the data rate changes. so the outer tracks have more data on them, which is read at a higher speed in megabytes/second