On Dec 22, 2009, at 10:14 PM, John R Pierce <pierce at hogranch.com> wrote: > Ross Walker wrote: >> Also, for random IO the opposite is true, the rotational latency is >> significantly smaller on the inner tracks than the outer tracks, so >> random OPs perform better there. >> > > um, most all hard disks are CAV, so the rotational latency measured in > milliseconds is constant throughout the disk. usually 50% of a turn > is > the assumed mean rotational latency I think you might be confusing CAV with CLV of optical drives. http://en.m.wikipedia.org/wiki/Constant_Angular_Velocity -Ross