A steerable vacuum cleaner and a method to steer the vacuum is described. The outer peripheral side rotor is arranged such that a rotational axis thereof is coaxial with a rotational axis of the inner periphery side rotor. Identifying a process log filter rule associated with the entity can include identifying an entity property and determining at least one process log filter rule corresponding to the identified entity property. In some cases, a measure related to the voltage difference between the ground references is first determined, and then the powervoltage that is ultimately delivered to the device or component is adjusted or compensated based, at least in part, on the determined difference. In this recording medium, a groove track in the control data area is divided into a plurality of mark portions and space portions based on a frequency band of a recording RF signal.